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linux/fs/btrfs
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Anand Jain c1310fc7ab btrfs: scan device in non-exclusive mode 
commit 50d281fc43 upstream.

This fixes mkfs/mount/check failures due to race with systemd-udevd
scan.

During the device scan initiated by systemd-udevd, other user space
EXCL operations such as mkfs, mount, or check may get blocked and result
in a "Device or resource busy" error. This is because the device
scan process opens the device with the EXCL flag in the kernel.

Two reports were received:

 - btrfs/179 test case, where the fsck command failed with the -EBUSY
   error

 - LTP pwritev03 test case, where mkfs.vfs failed with
   the -EBUSY error, when mkfs.vfs tried to overwrite old btrfs filesystem
   on the device.

In both cases, fsck and mkfs (respectively) were racing with a
systemd-udevd device scan, and systemd-udevd won, resulting in the
-EBUSY error for fsck and mkfs.

Reproducing the problem has been difficult because there is a very
small window during which these userspace threads can race to
acquire the exclusive device open. Even on the system where the problem
was observed, the problem occurrences were anywhere between 10 to 400
iterations and chances of reproducing decreases with debug printk()s.

However, an exclusive device open is unnecessary for the scan process,
as there are no write operations on the device during scan. Furthermore,
during the mount process, the superblock is re-read in the below
function call chain:

  btrfs_mount_root
   btrfs_open_devices
    open_fs_devices
     btrfs_open_one_device
       btrfs_get_bdev_and_sb

So, to fix this issue, removes the FMODE_EXCL flag from the scan
operation, and add a comment.

The case where mkfs may still write to the device and a scan is running,
the btrfs signature is not written at that time so scan will not
recognize such device.

Reported-by: Sherry Yang <sherry.yang@oracle.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202303170839.fdf23068-oliver.sang@intel.com
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2023-04-05 11:24:59 +02:00
..
tests btrfs: remove pointless and double ulist frees in error paths of qgroup tests 2022-11-26 09:24:32 +01:00
acl.c overlayfs update for 5.15 2021-09-02 09:21:27 -07:00
async-thread.c btrfs: fix memory ordering between normal and ordered work functions 2021-11-25 09:48:46 +01:00
async-thread.h Btrfs: fix crash during unmount due to race with delayed inode workers 2020-03-23 17:01:51 +01:00
backref.c btrfs: fix resolving backrefs for inline extent followed by prealloc 2023-01-12 11:58:50 +01:00
backref.h btrfs: sink iterator parameter to btrfs_ioctl_logical_to_ino 2022-12-08 11:28:38 +01:00
block-group.c btrfs: fix percent calculation for bg reclaim message 2023-03-17 08:48:47 +01:00
block-group.h btrfs: fix space cache corruption and potential double allocations 2022-09-05 10:30:12 +02:00
block-rsv.c btrfs: introduce mount option rescue=ignorebadroots 2020-12-08 15:53:41 +01:00
block-rsv.h btrfs: Remove __ prefix from btrfs_block_rsv_release 2020-03-23 17:01:55 +01:00
btrfs_inode.h btrfs: put initial index value of a directory in a constant 2022-08-31 17:16:35 +02:00
check-integrity.c btrfs: rename btrfs_bio to btrfs_io_context 2022-07-21 21:24:32 +02:00
check-integrity.h btrfs: remove btrfsic_submit_bh() 2020-03-23 17:01:39 +01:00
compression.c btrfs: remove unused parameter nr_pages in add_ra_bio_pages() 2022-04-20 09:34:04 +02:00
compression.h btrfs: rework btrfs_decompress_buf2page() 2021-08-23 13:19:04 +02:00
ctree.c btrfs: fix lockdep splat with reloc root extent buffers 2022-09-05 10:30:12 +02:00
ctree.h btrfs: fix space cache corruption and potential double allocations 2022-09-05 10:30:12 +02:00
delalloc-space.c btrfs: convert count_max_extents() to use fs_info->max_extent_size 2022-08-31 17:16:34 +02:00
delalloc-space.h btrfs: make btrfs_delalloc_reserve_space take btrfs_inode 2020-07-27 12:55:36 +02:00
delayed-inode.c btrfs: add ro compat flags to inodes 2021-08-23 13:19:09 +02:00
delayed-inode.h btrfs: make btrfs_delayed_update_inode take btrfs_inode 2020-12-08 15:54:10 +01:00
delayed-ref.c btrfs: fix lock inversion problem when doing qgroup extent tracing 2021-07-22 15:50:07 +02:00
delayed-ref.h btrfs: add additional parameters to btrfs_init_tree_ref/btrfs_init_data_ref 2022-07-12 16:34:50 +02:00
dev-replace.c btrfs: add info when mount fails due to stale replace target 2022-08-31 17:16:46 +02:00
dev-replace.h btrfs: zoned: mark block groups to copy for device-replace 2021-02-09 02:46:07 +01:00
dir-item.c btrfs: unify lookup return value when dir entry is missing 2021-10-07 22:06:32 +02:00
discard.c btrfs: hold block group refcount during async discard 2023-03-10 09:39:56 +01:00
discard.h btrfs: cleanup btrfs_discard_update_discardable usage 2020-12-08 15:54:02 +01:00
disk-io.c btrfs: do not abort transaction on failure to write log tree when syncing log 2023-01-24 07:22:46 +01:00
disk-io.h btrfs: make thaw time super block check to also verify checksum 2023-01-12 11:59:20 +01:00
export.c btrfs: fix type of parameter generation in btrfs_get_dentry 2022-11-10 18:15:38 +01:00
export.h btrfs: fix type of parameter generation in btrfs_get_dentry 2022-11-10 18:15:38 +01:00
extent-io-tree.h btrfs: use fixed width int type for extent_state::state 2020-12-08 15:54:13 +01:00
extent-tree.c btrfs: always report error in run_one_delayed_ref() 2023-01-24 07:22:42 +01:00
extent_io.c btrfs: fix lockdep splat with reloc root extent buffers 2022-09-05 10:30:12 +02:00
extent_io.h btrfs: fix qgroup reserve overflow the qgroup limit 2022-04-13 20:59:23 +02:00
extent_map.c btrfs: rename btrfs_bio to btrfs_io_context 2022-07-21 21:24:32 +02:00
extent_map.h btrfs: remove extent_map::bdev 2019-11-18 23:43:44 +01:00
file-item.c btrfs: make search_csum_tree return 0 if we get -EFBIG 2022-04-08 14:23:58 +02:00
file.c btrfs: do not BUG_ON() on ENOMEM when dropping extent items for a range 2022-12-31 13:14:47 +01:00
free-space-cache.c btrfs: dump extra info if one free space cache has more bitmaps than it should 2022-10-26 12:35:44 +02:00
free-space-cache.h btrfs: zoned: track unusable bytes for zones 2021-02-09 02:46:03 +01:00
free-space-tree.c btrfs: fix invalid delayed ref after subvolume creation failure 2022-07-12 16:34:50 +02:00
free-space-tree.h btrfs: rename btrfs_block_group_cache 2019-11-18 17:51:51 +01:00
inode-item.c btrfs: locking: rip out path->leave_spinning 2020-12-08 15:54:02 +01:00
inode.c btrfs: remove root argument from btrfs_unlink_inode() 2022-09-05 10:30:09 +02:00
ioctl.c btrfs: fix race between quota disable and quota assign ioctls 2023-04-05 11:24:59 +02:00
Kconfig btrfs: disable build on platforms having page size 256K 2021-06-22 14:11:57 +02:00
locking.c btrfs: fix lockdep splat with reloc root extent buffers 2022-09-05 10:30:12 +02:00
locking.h btrfs: fix lockdep splat with reloc root extent buffers 2022-09-05 10:30:12 +02:00
lzo.c btrfs: prevent copying too big compressed lzo segment 2022-03-02 11:48:07 +01:00
Makefile btrfs: initial fsverity support 2021-08-23 13:19:09 +02:00
misc.h btrfs: use correct header for div_u64 in misc.h 2021-09-07 14:29:50 +02:00
ordered-data.c btrfs: zoned: fix double counting of split ordered extent 2021-09-07 14:30:41 +02:00
ordered-data.h btrfs: remove uptodate parameter from btrfs_dec_test_first_ordered_pending 2021-08-23 13:19:02 +02:00
orphan.c btrfs: replace GPL boilerplate by SPDX -- sources 2018-04-12 16:29:51 +02:00
print-tree.c btrfs: print the actual offset in btrfs_root_name 2021-01-07 17:25:05 +01:00
print-tree.h btrfs: print the actual offset in btrfs_root_name 2021-01-07 17:25:05 +01:00
props.c btrfs: props: change how empty value is interpreted 2021-06-22 14:11:58 +02:00
props.h btrfs: delete unused function btrfs_set_prop_trans 2019-04-29 19:02:54 +02:00
qgroup.c btrfs: fix race between quota disable and quota assign ioctls 2023-04-05 11:24:59 +02:00
qgroup.h btrfs: fix lock inversion problem when doing qgroup extent tracing 2021-07-22 15:50:07 +02:00
raid56.c btrfs: raid56: properly handle the error when unable to find the missing stripe 2022-11-26 09:24:31 +01:00
raid56.h btrfs: rename btrfs_bio to btrfs_io_context 2022-07-21 21:24:32 +02:00
rcu-string.h btrfs: replace strncpy() with strscpy() 2023-01-12 11:59:05 +01:00
reada.c btrfs: rename btrfs_bio to btrfs_io_context 2022-07-21 21:24:32 +02:00
ref-verify.c btrfs: stop doing GFP_KERNEL memory allocations in the ref verify tool 2021-08-23 13:19:00 +02:00
ref-verify.h btrfs: ref-verify: Use btrfs_ref to refactor btrfs_ref_tree_mod() 2019-04-29 19:02:49 +02:00
reflink.c btrfs: fix unexpected error path when reflinking an inline extent 2022-04-08 14:23:11 +02:00
reflink.h Btrfs: move all reflink implementation code into its own file 2020-03-23 17:01:54 +01:00
relocation.c btrfs: fix lockdep splat with reloc root extent buffers 2022-09-05 10:30:12 +02:00
root-tree.c btrfs: fix silent failure when deleting root reference 2022-08-31 17:16:46 +02:00
scrub.c btrfs: scrub: try to fix super block errors 2022-10-26 12:35:44 +02:00
send.c btrfs: send: limit number of clones and allocated memory size 2023-03-03 11:45:52 +01:00
send.h btrfs: send: avoid copying file data 2020-10-07 12:13:17 +02:00
space-info.c btrfs: extend locking to all space_info members accesses 2022-04-08 14:23:02 +02:00
space-info.h btrfs: rip out btrfs_space_info::total_bytes_pinned 2021-06-22 14:55:25 +02:00
struct-funcs.c btrfs: add special case to setget helpers for 64k pages 2021-08-23 13:18:58 +02:00
subpage.c btrfs: subpage: fix a potential use-after-free in writeback helper 2021-08-23 13:19:05 +02:00
subpage.h btrfs: subpage: fix writeback which does not have ordered extent 2021-08-23 13:19:04 +02:00
super.c btrfs: make thaw time super block check to also verify checksum 2023-01-12 11:59:20 +01:00
sysfs.c btrfs: sysfs: normalize the error handling branch in btrfs_init_sysfs() 2022-12-02 17:41:12 +01:00
sysfs.h btrfs: split and refactor btrfs_sysfs_remove_devices_dir 2020-10-07 12:12:21 +02:00
transaction.c btrfs: make send work with concurrent block group relocation 2022-03-16 14:23:46 +01:00
transaction.h btrfs: do not start relocation until in progress drops are done 2022-03-08 19:12:54 +01:00
tree-checker.c btrfs: tree-checker: check for overlapping extent items 2022-09-05 10:30:12 +02:00
tree-checker.h btrfs: get fs_info from eb in btrfs_check_chunk_valid 2019-04-29 19:02:39 +02:00
tree-defrag.c btrfs: fix an error handling path in btrfs_defrag_leaves() 2023-01-12 11:59:08 +01:00
tree-log.c btrfs: do not abort transaction on failure to write log tree when syncing log 2023-01-24 07:22:46 +01:00
tree-log.h btrfs: pass the dentry to btrfs_log_new_name() instead of the inode 2022-08-31 17:16:36 +02:00
tree-mod-log.c btrfs: fix race when picking most recent mod log operation for an old root 2021-04-20 19:27:17 +02:00
tree-mod-log.h btrfs: add and use helper to get lowest sequence number for the tree mod log 2021-04-19 17:25:17 +02:00
ulist.c btrfs: replace GPL boilerplate by SPDX -- sources 2018-04-12 16:29:51 +02:00
ulist.h btrfs: replace GPL boilerplate by SPDX -- headers 2018-04-12 16:29:46 +02:00
uuid-tree.c btrfs: remove unnecessary casts in printk 2020-12-08 15:53:52 +01:00
verity.c btrfs: fix transaction handle leak after verity rollback failure 2021-09-17 19:29:41 +02:00
volumes.c btrfs: scan device in non-exclusive mode 2023-04-05 11:24:59 +02:00
volumes.h btrfs: zoned: initialize device's zone info for seeding 2022-11-16 09:58:27 +01:00
xattr.c btrfs: check if root is readonly while setting security xattr 2022-08-31 17:16:46 +02:00
xattr.h btrfs: cleanup btrfs_setxattr_trans and drop transaction parameter 2019-04-29 19:02:44 +02:00
zlib.c btrfs: zlib: zero-initialize zlib workspace 2023-02-14 19:17:56 +01:00
zoned.c btrfs: use kvcalloc in btrfs_get_dev_zone_info 2022-12-02 17:41:12 +01:00
zoned.h btrfs: zoned: revive max_zone_append_bytes 2022-08-31 17:16:34 +02:00
zstd.c Revert "btrfs: compression: drop kmap/kunmap from zstd" 2021-10-29 13:02:50 +02:00