block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-23 08:11:50 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-11-15 21:15:54 +09:00
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zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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2026-03-23 08:11:50 +01:00
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2026-03-27 05:32:45 +09:00
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|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-11-15 21:15:54 +09:00
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|
zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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|
2026-03-23 08:11:50 +01:00
|
|
|
|
2026-03-27 05:32:45 +09:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-11-15 21:15:54 +09:00
|
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|
|
zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
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|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-11-15 21:15:54 +09:00
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zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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2026-03-23 08:11:50 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
|
|
|
|
2026-03-27 05:32:45 +09:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-11-15 21:15:54 +09:00
|
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|
zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
|
|
|
|
2026-03-23 08:11:50 +01:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
|
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|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
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2026-04-14 10:17:50 +02:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-04-14 10:17:48 +02:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-04-14 10:17:51 +02:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
|
|
|
|
2026-04-14 10:17:50 +02:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
|
|
|
|
2026-04-14 10:17:50 +02:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
|
|
|
|
2026-03-27 05:32:45 +09:00
|
|
|
|
|
|
|
|
|
|
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-04-14 10:17:51 +02:00
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|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
|
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-04-14 10:17:51 +02:00
|
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2026-03-27 05:32:45 +09:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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|
|
|
2026-04-14 10:17:51 +02:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-04-14 10:17:51 +02:00
|
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|
2026-04-14 10:17:50 +02:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
|
|
|
|
2026-04-14 10:17:51 +02:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-04-14 10:17:51 +02:00
|
|
|
|
2026-04-14 10:17:50 +02:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
|
|
|
|
2026-04-14 10:17:51 +02:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-23 08:11:49 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-23 08:11:49 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-23 08:11:49 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-23 08:11:49 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-20 23:49:23 -08:00
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2026-03-23 08:11:49 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-23 08:11:49 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-23 08:11:49 +01:00
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2026-04-14 10:17:51 +02:00
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2026-03-23 08:11:49 +01:00
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2026-03-27 05:32:45 +09:00
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2026-03-23 08:11:49 +01:00
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2026-04-14 10:17:50 +02:00
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2026-03-23 08:11:49 +01:00
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2026-04-14 10:17:51 +02:00
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2026-03-23 08:11:49 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-23 08:11:49 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-23 08:11:50 +01:00
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2026-02-24 06:21:44 -08:00
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2026-03-23 08:11:50 +01:00
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2026-02-24 06:21:44 -08:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-11-19 15:22:34 -08:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-02-24 06:21:44 -08:00
|
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|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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2026-04-14 10:17:51 +02:00
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|
zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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|
|
|
2026-04-14 10:17:51 +02:00
|
|
|
|
zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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2026-04-14 10:17:50 +02:00
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zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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2026-04-14 10:17:51 +02:00
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|
zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-04-14 10:17:49 +02:00
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|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
|
|
|
|
2026-04-14 10:17:49 +02:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
|
|
|
|
zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-11-05 06:22:38 +09:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-04-14 10:17:51 +02:00
|
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|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-04-14 10:17:51 +02:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-11-05 06:22:38 +09:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-07-31 20:07:45 +09:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
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zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-02-24 06:21:44 -08:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
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2026-02-21 17:06:51 -08:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-12-15 23:21:06 +08:00
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2026-03-27 05:32:45 +09:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-11-15 21:15:54 +09:00
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zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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2026-03-23 08:11:50 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-11-15 21:15:54 +09:00
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2026-03-27 05:32:45 +09:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-12-15 23:21:06 +08:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
|
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|
|
|
|
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|
2025-11-15 21:15:54 +09:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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|
zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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2025-11-15 21:15:54 +09:00
|
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|
zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
|
|
|
|
2025-11-15 21:15:54 +09:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-23 08:11:50 +01:00
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2026-04-14 10:17:46 +02:00
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2026-04-14 10:17:47 +02:00
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2026-03-23 08:11:50 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-02-24 06:21:45 -08:00
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|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-12-15 23:21:06 +08:00
|
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|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-23 08:11:50 +01:00
|
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|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
|
|
|
|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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|
|
2025-11-15 21:15:54 +09:00
|
|
|
|
zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
|
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|
block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2026-03-27 05:32:45 +09:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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2025-11-15 21:15:54 +09:00
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zloop: introduce the ordered_zone_append configuration parameter
The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-15 21:15:55 +09:00
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2026-03-23 08:11:50 +01:00
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block: new zoned loop block device driver
The zoned loop block device driver allows a user to create emulated
zoned block devices using one regular file per zone as backing storage.
Compared to null_blk or scsi_debug, it has the advantage of allowing
emulating large zoned devices without requiring the same amount of
memory as the capacity of the emulated device. Furthermore, zoned
devices emulated with this driver can be re-started after a host reboot
without any loss of the state of the device zones, which is something
that null_blk and scsi_debug do not support.
This initial implementation is simple and does not support zone resource
limits. That is, a zoned loop block device limits for the maximum number
of open zones and maximum number of active zones is always 0.
This driver can be either compiled in-kernel or as a module, named
"zloop". Compilation of this driver depends on the block layer support
for zoned block device (CONFIG_BLK_DEV_ZONED must be set).
Using the zloop driver to create and delete zoned block devices is
done by writing commands to the zoned loop control character device file
(/dev/zloop-control). Creating a device is done with:
$ echo "add [options]" > /dev/zloop-control
The options available for the "add" operation cat be listed by reading
the zloop-control device file:
$ cat /dev/zloop-control
add id=%d,capacity_mb=%u,zone_size_mb=%u,zone_capacity_mb=%u,conv_zones=%u,base_dir=%s,nr_queues=%u,queue_depth=%u
remove id=%d
The options available allow controlling the zoned device total
capacity, zone size, zone capactity of sequential zones, total number
of conventional zones, base directory for the zones backing file, number
of I/O queues and the maximum queue depth of I/O queues.
Deleting a device is done using the "remove" command:
$ echo "remove id=0" > /dev/zloop-control
This implementation passes various tests using zonefs and fio (t/zbd
tests) and provides a state machine for zone conditions that is
compliant with the T10 ZBC and NVMe ZNS specifications.
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20250407075222.170336-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07 16:52:21 +09:00
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