2005-09-09 13:10:27 -07:00
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2008-11-26 12:03:54 +01:00
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2005-09-09 13:10:27 -07:00
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fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2010-05-25 15:06:07 +02:00
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2005-09-09 13:10:27 -07:00
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driver core: add devname module aliases to allow module on-demand auto-loading
This adds:
alias: devname:<name>
to some common kernel modules, which will allow the on-demand loading
of the kernel module when the device node is accessed.
Ideally all these modules would be compiled-in, but distros seems too
much in love with their modularization that we need to cover the common
cases with this new facility. It will allow us to remove a bunch of pretty
useless init scripts and modprobes from init scripts.
The static device node aliases will be carried in the module itself. The
program depmod will extract this information to a file in the module directory:
$ cat /lib/modules/2.6.34-00650-g537b60d-dirty/modules.devname
# Device nodes to trigger on-demand module loading.
microcode cpu/microcode c10:184
fuse fuse c10:229
ppp_generic ppp c108:0
tun net/tun c10:200
dm_mod mapper/control c10:235
Udev will pick up the depmod created file on startup and create all the
static device nodes which the kernel modules specify, so that these modules
get automatically loaded when the device node is accessed:
$ /sbin/udevd --debug
...
static_dev_create_from_modules: mknod '/dev/cpu/microcode' c10:184
static_dev_create_from_modules: mknod '/dev/fuse' c10:229
static_dev_create_from_modules: mknod '/dev/ppp' c108:0
static_dev_create_from_modules: mknod '/dev/net/tun' c10:200
static_dev_create_from_modules: mknod '/dev/mapper/control' c10:235
udev_rules_apply_static_dev_perms: chmod '/dev/net/tun' 0666
udev_rules_apply_static_dev_perms: chmod '/dev/fuse' 0666
A few device nodes are switched to statically allocated numbers, to allow
the static nodes to work. This might also useful for systems which still run
a plain static /dev, which is completely unsafe to use with any dynamic minor
numbers.
Note:
The devname aliases must be limited to the *common* and *single*instance*
device nodes, like the misc devices, and never be used for conceptually limited
systems like the loop devices, which should rather get fixed properly and get a
control node for losetup to talk to, instead of creating a random number of
device nodes in advance, regardless if they are ever used.
This facility is to hide the mess distros are creating with too modualized
kernels, and just to hide that these modules are not compiled-in, and not to
paper-over broken concepts. Thanks! :)
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Cc: Ian Kent <raven@themaw.net>
Signed-Off-By: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-05-20 18:07:20 +02:00
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2005-09-09 13:10:27 -07:00
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2006-12-06 20:33:20 -08:00
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2005-09-09 13:10:27 -07:00
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2006-01-16 22:14:28 -08:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-01-16 22:14:28 -08:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:54 -07:00
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2005-09-09 13:10:27 -07:00
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2006-12-06 20:33:17 -08:00
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2005-09-09 13:10:27 -07:00
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2009-04-14 10:54:53 +09:00
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2005-09-09 13:10:27 -07:00
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fuse: support writable mmap
Quoting Linus (3 years ago, FUSE inclusion discussions):
"User-space filesystems are hard to get right. I'd claim that they
are almost impossible, unless you limit them somehow (shared
writable mappings are the nastiest part - if you don't have those,
you can reasonably limit your problems by limiting the number of
dirty pages you accept through normal "write()" calls)."
Instead of attempting the impossible, I've just waited for the dirty page
accounting infrastructure to materialize (thanks to Peter Zijlstra and
others). This nicely solved the biggest problem: limiting the number of pages
used for write caching.
Some small details remained, however, which this largish patch attempts to
address. It provides a page writeback implementation for fuse, which is
completely safe against VM related deadlocks. Performance may not be very
good for certain usage patterns, but generally it should be acceptable.
It has been tested extensively with fsx-linux and bash-shared-mapping.
Fuse page writeback design
--------------------------
fuse_writepage() allocates a new temporary page with GFP_NOFS|__GFP_HIGHMEM.
It copies the contents of the original page, and queues a WRITE request to the
userspace filesystem using this temp page.
The writeback is finished instantly from the MM's point of view: the page is
removed from the radix trees, and the PageDirty and PageWriteback flags are
cleared.
For the duration of the actual write, the NR_WRITEBACK_TEMP counter is
incremented. The per-bdi writeback count is not decremented until the actual
write completes.
On dirtying the page, fuse waits for a previous write to finish before
proceeding. This makes sure, there can only be one temporary page used at a
time for one cached page.
This approach is wasteful in both memory and CPU bandwidth, so why is this
complication needed?
The basic problem is that there can be no guarantee about the time in which
the userspace filesystem will complete a write. It may be buggy or even
malicious, and fail to complete WRITE requests. We don't want unrelated parts
of the system to grind to a halt in such cases.
Also a filesystem may need additional resources (particularly memory) to
complete a WRITE request. There's a great danger of a deadlock if that
allocation may wait for the writepage to finish.
Currently there are several cases where the kernel can block on page
writeback:
- allocation order is larger than PAGE_ALLOC_COSTLY_ORDER
- page migration
- throttle_vm_writeout (through NR_WRITEBACK)
- sync(2)
Of course in some cases (fsync, msync) we explicitly want to allow blocking.
So for these cases new code has to be added to fuse, since the VM is not
tracking writeback pages for us any more.
As an extra safetly measure, the maximum dirty ratio allocated to a single
fuse filesystem is set to 1% by default. This way one (or several) buggy or
malicious fuse filesystems cannot slow down the rest of the system by hogging
dirty memory.
With appropriate privileges, this limit can be raised through
'/sys/class/bdi/<bdi>/max_ratio'.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 00:54:41 -07:00
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2005-09-09 13:10:27 -07:00
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2006-01-16 22:14:28 -08:00
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2005-09-09 13:10:27 -07:00
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2006-01-16 22:14:28 -08:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:52 -07:00
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2008-11-14 10:38:53 +11:00
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2006-06-25 05:48:52 -07:00
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2006-04-10 22:54:58 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:59 -07:00
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2006-04-11 21:16:09 +02:00
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2006-04-10 22:54:59 -07:00
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2006-04-11 21:16:09 +02:00
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2006-04-10 22:54:59 -07:00
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2006-04-11 21:16:09 +02:00
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2006-04-10 22:54:59 -07:00
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2006-04-11 21:16:09 +02:00
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2006-04-10 22:54:59 -07:00
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2006-06-25 05:48:50 -07:00
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2006-04-10 22:54:59 -07:00
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2006-04-11 21:16:09 +02:00
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2006-04-10 22:54:58 -07:00
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2006-04-11 21:16:09 +02:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:52 -07:00
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2006-04-11 21:16:09 +02:00
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2005-09-09 13:10:27 -07:00
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2006-04-11 21:16:09 +02:00
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2005-09-09 13:10:27 -07:00
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2009-04-14 10:54:53 +09:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:52 -07:00
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2007-10-16 23:31:00 -07:00
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2006-06-25 05:48:52 -07:00
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2007-10-16 23:31:00 -07:00
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2006-06-25 05:48:52 -07:00
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2005-09-09 13:10:27 -07:00
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2006-02-04 23:27:40 -08:00
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2006-04-11 21:16:09 +02:00
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2006-06-25 05:48:52 -07:00
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2006-02-04 23:27:40 -08:00
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2009-04-14 10:54:53 +09:00
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2006-02-04 23:27:40 -08:00
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2008-02-06 01:38:39 -08:00
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2009-07-01 17:28:41 -07:00
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2008-02-06 01:38:39 -08:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:53 -07:00
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2006-01-16 22:14:26 -08:00
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2006-06-25 05:48:50 -07:00
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2006-02-04 23:27:40 -08:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2008-12-02 14:49:42 +01:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:50 -07:00
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2006-01-16 22:14:31 -08:00
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2006-06-25 05:48:54 -07:00
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2006-01-16 22:14:31 -08:00
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2006-06-25 05:48:50 -07:00
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2009-07-01 17:28:41 -07:00
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2006-06-25 05:48:50 -07:00
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2009-07-01 17:28:41 -07:00
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2009-04-14 10:54:52 +09:00
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2009-07-09 14:52:32 +02:00
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2007-10-16 23:30:59 -07:00
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2006-06-25 05:48:50 -07:00
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2008-02-06 01:38:39 -08:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:50 -07:00
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2008-11-26 12:03:54 +01:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:54 -07:00
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2008-12-02 14:49:42 +01:00
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2006-06-25 05:48:54 -07:00
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2005-09-09 13:10:39 -07:00
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2008-12-02 14:49:42 +01:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:54 -07:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:54 -07:00
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2007-10-16 23:31:04 -07:00
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2006-06-25 05:48:54 -07:00
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2006-06-25 05:48:50 -07:00
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2006-06-25 05:48:54 -07:00
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2006-06-25 05:48:50 -07:00
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2007-10-16 23:31:04 -07:00
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2006-06-25 05:48:50 -07:00
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2005-09-09 13:10:27 -07:00
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2007-10-16 23:31:04 -07:00
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2006-06-25 05:48:54 -07:00
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2007-10-16 23:31:04 -07:00
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2006-06-25 05:48:54 -07:00
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2007-10-16 23:31:04 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2008-11-26 12:03:55 +01:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:31 -07:00
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2005-09-09 13:10:27 -07:00
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2005-09-09 13:10:39 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2009-04-14 10:54:53 +09:00
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2005-09-09 13:10:27 -07:00
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2008-11-26 12:03:55 +01:00
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2008-02-06 01:38:39 -08:00
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2009-07-01 17:28:41 -07:00
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2008-02-06 01:38:39 -08:00
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2009-07-01 17:28:41 -07:00
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2009-04-14 10:54:52 +09:00
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2009-07-09 14:52:32 +02:00
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2008-02-06 01:38:39 -08:00
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2008-11-26 12:03:55 +01:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:31 -07:00
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2008-11-26 12:03:55 +01:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2008-11-26 12:03:55 +01:00
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2005-09-09 13:10:27 -07:00
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2008-11-26 12:03:55 +01:00
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2005-09-09 13:10:27 -07:00
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2008-11-26 12:03:55 +01:00
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2005-09-09 13:10:27 -07:00
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2008-11-26 12:03:55 +01:00
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2005-09-09 13:10:27 -07:00
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2009-04-14 10:54:53 +09:00
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2005-09-09 13:10:27 -07:00
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fuse: support writable mmap
Quoting Linus (3 years ago, FUSE inclusion discussions):
"User-space filesystems are hard to get right. I'd claim that they
are almost impossible, unless you limit them somehow (shared
writable mappings are the nastiest part - if you don't have those,
you can reasonably limit your problems by limiting the number of
dirty pages you accept through normal "write()" calls)."
Instead of attempting the impossible, I've just waited for the dirty page
accounting infrastructure to materialize (thanks to Peter Zijlstra and
others). This nicely solved the biggest problem: limiting the number of pages
used for write caching.
Some small details remained, however, which this largish patch attempts to
address. It provides a page writeback implementation for fuse, which is
completely safe against VM related deadlocks. Performance may not be very
good for certain usage patterns, but generally it should be acceptable.
It has been tested extensively with fsx-linux and bash-shared-mapping.
Fuse page writeback design
--------------------------
fuse_writepage() allocates a new temporary page with GFP_NOFS|__GFP_HIGHMEM.
It copies the contents of the original page, and queues a WRITE request to the
userspace filesystem using this temp page.
The writeback is finished instantly from the MM's point of view: the page is
removed from the radix trees, and the PageDirty and PageWriteback flags are
cleared.
For the duration of the actual write, the NR_WRITEBACK_TEMP counter is
incremented. The per-bdi writeback count is not decremented until the actual
write completes.
On dirtying the page, fuse waits for a previous write to finish before
proceeding. This makes sure, there can only be one temporary page used at a
time for one cached page.
This approach is wasteful in both memory and CPU bandwidth, so why is this
complication needed?
The basic problem is that there can be no guarantee about the time in which
the userspace filesystem will complete a write. It may be buggy or even
malicious, and fail to complete WRITE requests. We don't want unrelated parts
of the system to grind to a halt in such cases.
Also a filesystem may need additional resources (particularly memory) to
complete a WRITE request. There's a great danger of a deadlock if that
allocation may wait for the writepage to finish.
Currently there are several cases where the kernel can block on page
writeback:
- allocation order is larger than PAGE_ALLOC_COSTLY_ORDER
- page migration
- throttle_vm_writeout (through NR_WRITEBACK)
- sync(2)
Of course in some cases (fsync, msync) we explicitly want to allow blocking.
So for these cases new code has to be added to fuse, since the VM is not
tracking writeback pages for us any more.
As an extra safetly measure, the maximum dirty ratio allocated to a single
fuse filesystem is set to 1% by default. This way one (or several) buggy or
malicious fuse filesystems cannot slow down the rest of the system by hogging
dirty memory.
With appropriate privileges, this limit can be raised through
'/sys/class/bdi/<bdi>/max_ratio'.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 00:54:41 -07:00
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2008-11-26 12:03:55 +01:00
|
|
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|
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|
|
|
|
fuse: support writable mmap
Quoting Linus (3 years ago, FUSE inclusion discussions):
"User-space filesystems are hard to get right. I'd claim that they
are almost impossible, unless you limit them somehow (shared
writable mappings are the nastiest part - if you don't have those,
you can reasonably limit your problems by limiting the number of
dirty pages you accept through normal "write()" calls)."
Instead of attempting the impossible, I've just waited for the dirty page
accounting infrastructure to materialize (thanks to Peter Zijlstra and
others). This nicely solved the biggest problem: limiting the number of pages
used for write caching.
Some small details remained, however, which this largish patch attempts to
address. It provides a page writeback implementation for fuse, which is
completely safe against VM related deadlocks. Performance may not be very
good for certain usage patterns, but generally it should be acceptable.
It has been tested extensively with fsx-linux and bash-shared-mapping.
Fuse page writeback design
--------------------------
fuse_writepage() allocates a new temporary page with GFP_NOFS|__GFP_HIGHMEM.
It copies the contents of the original page, and queues a WRITE request to the
userspace filesystem using this temp page.
The writeback is finished instantly from the MM's point of view: the page is
removed from the radix trees, and the PageDirty and PageWriteback flags are
cleared.
For the duration of the actual write, the NR_WRITEBACK_TEMP counter is
incremented. The per-bdi writeback count is not decremented until the actual
write completes.
On dirtying the page, fuse waits for a previous write to finish before
proceeding. This makes sure, there can only be one temporary page used at a
time for one cached page.
This approach is wasteful in both memory and CPU bandwidth, so why is this
complication needed?
The basic problem is that there can be no guarantee about the time in which
the userspace filesystem will complete a write. It may be buggy or even
malicious, and fail to complete WRITE requests. We don't want unrelated parts
of the system to grind to a halt in such cases.
Also a filesystem may need additional resources (particularly memory) to
complete a WRITE request. There's a great danger of a deadlock if that
allocation may wait for the writepage to finish.
Currently there are several cases where the kernel can block on page
writeback:
- allocation order is larger than PAGE_ALLOC_COSTLY_ORDER
- page migration
- throttle_vm_writeout (through NR_WRITEBACK)
- sync(2)
Of course in some cases (fsync, msync) we explicitly want to allow blocking.
So for these cases new code has to be added to fuse, since the VM is not
tracking writeback pages for us any more.
As an extra safetly measure, the maximum dirty ratio allocated to a single
fuse filesystem is set to 1% by default. This way one (or several) buggy or
malicious fuse filesystems cannot slow down the rest of the system by hogging
dirty memory.
With appropriate privileges, this limit can be raised through
'/sys/class/bdi/<bdi>/max_ratio'.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 00:54:41 -07:00
|
|
|
|
|
|
|
|
|
2008-11-26 12:03:55 +01:00
|
|
|
|
fuse: support writable mmap
Quoting Linus (3 years ago, FUSE inclusion discussions):
"User-space filesystems are hard to get right. I'd claim that they
are almost impossible, unless you limit them somehow (shared
writable mappings are the nastiest part - if you don't have those,
you can reasonably limit your problems by limiting the number of
dirty pages you accept through normal "write()" calls)."
Instead of attempting the impossible, I've just waited for the dirty page
accounting infrastructure to materialize (thanks to Peter Zijlstra and
others). This nicely solved the biggest problem: limiting the number of pages
used for write caching.
Some small details remained, however, which this largish patch attempts to
address. It provides a page writeback implementation for fuse, which is
completely safe against VM related deadlocks. Performance may not be very
good for certain usage patterns, but generally it should be acceptable.
It has been tested extensively with fsx-linux and bash-shared-mapping.
Fuse page writeback design
--------------------------
fuse_writepage() allocates a new temporary page with GFP_NOFS|__GFP_HIGHMEM.
It copies the contents of the original page, and queues a WRITE request to the
userspace filesystem using this temp page.
The writeback is finished instantly from the MM's point of view: the page is
removed from the radix trees, and the PageDirty and PageWriteback flags are
cleared.
For the duration of the actual write, the NR_WRITEBACK_TEMP counter is
incremented. The per-bdi writeback count is not decremented until the actual
write completes.
On dirtying the page, fuse waits for a previous write to finish before
proceeding. This makes sure, there can only be one temporary page used at a
time for one cached page.
This approach is wasteful in both memory and CPU bandwidth, so why is this
complication needed?
The basic problem is that there can be no guarantee about the time in which
the userspace filesystem will complete a write. It may be buggy or even
malicious, and fail to complete WRITE requests. We don't want unrelated parts
of the system to grind to a halt in such cases.
Also a filesystem may need additional resources (particularly memory) to
complete a WRITE request. There's a great danger of a deadlock if that
allocation may wait for the writepage to finish.
Currently there are several cases where the kernel can block on page
writeback:
- allocation order is larger than PAGE_ALLOC_COSTLY_ORDER
- page migration
- throttle_vm_writeout (through NR_WRITEBACK)
- sync(2)
Of course in some cases (fsync, msync) we explicitly want to allow blocking.
So for these cases new code has to be added to fuse, since the VM is not
tracking writeback pages for us any more.
As an extra safetly measure, the maximum dirty ratio allocated to a single
fuse filesystem is set to 1% by default. This way one (or several) buggy or
malicious fuse filesystems cannot slow down the rest of the system by hogging
dirty memory.
With appropriate privileges, this limit can be raised through
'/sys/class/bdi/<bdi>/max_ratio'.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 00:54:41 -07:00
|
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|
2005-09-09 13:10:27 -07:00
|
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|
2006-06-25 05:48:53 -07:00
|
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|
2005-09-09 13:10:27 -07:00
|
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2006-04-10 22:54:55 -07:00
|
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2006-06-25 05:48:53 -07:00
|
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:53 -07:00
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2005-09-09 13:10:27 -07:00
|
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:53 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2005-09-09 13:10:27 -07:00
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2010-05-25 15:06:07 +02:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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|
2010-05-25 15:06:07 +02:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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|
2006-01-16 22:14:28 -08:00
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|
2005-09-09 13:10:27 -07:00
|
|
|
|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2010-05-25 15:06:07 +02:00
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fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
|
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|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
|
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2010-05-25 15:06:07 +02:00
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|
|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
|
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2010-05-25 15:06:07 +02:00
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|
|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-01-16 22:14:28 -08:00
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2005-09-09 13:10:27 -07:00
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2010-05-25 15:06:07 +02:00
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2010-05-25 15:06:07 +02:00
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2005-09-09 13:10:27 -07:00
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2010-05-25 15:06:07 +02:00
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2006-01-16 22:14:28 -08:00
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2005-09-09 13:10:27 -07:00
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2010-05-25 15:06:07 +02:00
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2005-09-09 13:10:27 -07:00
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2010-05-25 15:06:07 +02:00
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2010-05-25 15:06:07 +02:00
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2008-11-26 12:03:54 +01:00
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2005-09-09 13:10:27 -07:00
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2010-05-25 15:06:07 +02:00
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2005-09-09 13:10:27 -07:00
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2008-11-26 12:03:54 +01:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:54 -07:00
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2005-09-09 13:10:27 -07:00
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2008-12-02 14:49:42 +01:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:54 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:54 -07:00
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2010-05-25 15:06:07 +02:00
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2008-12-02 14:49:42 +01:00
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2006-06-25 05:48:54 -07:00
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2010-05-25 15:06:07 +02:00
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2006-06-25 05:48:54 -07:00
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2010-05-25 15:06:07 +02:00
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2006-06-25 05:48:54 -07:00
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2010-05-25 15:06:07 +02:00
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2006-06-25 05:48:54 -07:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:53 -07:00
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2005-09-09 13:10:27 -07:00
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2010-05-25 15:06:07 +02:00
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2005-09-09 13:10:27 -07:00
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2006-01-06 00:19:40 -08:00
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2006-04-10 22:54:55 -07:00
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2006-04-10 22:54:53 -07:00
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2006-06-25 05:48:54 -07:00
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2006-04-10 22:54:53 -07:00
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2005-09-09 13:10:27 -07:00
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2006-01-16 22:14:34 -08:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:54 -07:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:54 -07:00
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2010-05-25 15:06:07 +02:00
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2006-06-25 05:48:54 -07:00
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2005-09-09 13:10:27 -07:00
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2006-01-16 22:14:31 -08:00
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2006-01-16 22:14:31 -08:00
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2005-09-09 13:10:27 -07:00
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2006-01-06 00:19:40 -08:00
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2010-05-25 15:06:07 +02:00
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2006-01-06 00:19:40 -08:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2010-05-25 15:06:07 +02:00
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2006-01-06 00:19:40 -08:00
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2010-05-25 15:06:07 +02:00
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2006-01-06 00:19:40 -08:00
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2010-05-25 15:06:07 +02:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2007-10-16 23:31:05 -07:00
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2005-09-09 13:10:27 -07:00
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2007-10-16 23:31:05 -07:00
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2005-09-09 13:10:27 -07:00
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2006-01-16 22:14:31 -08:00
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2006-01-16 22:14:31 -08:00
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2006-06-25 05:48:54 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2010-05-25 15:06:07 +02:00
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2008-11-26 12:03:55 +01:00
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2009-01-26 15:00:59 +01:00
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2008-11-26 12:03:55 +01:00
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2009-01-26 15:00:59 +01:00
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2008-11-26 12:03:55 +01:00
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2009-01-26 15:00:59 +01:00
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2008-11-26 12:03:55 +01:00
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2009-01-26 15:00:59 +01:00
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2008-11-26 12:03:55 +01:00
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2009-01-26 15:00:59 +01:00
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2008-11-26 12:03:55 +01:00
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2009-05-31 11:13:57 -04:00
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2010-02-05 12:08:31 +01:00
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2009-05-31 11:13:57 -04:00
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2009-12-30 18:37:13 +08:00
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2009-05-31 11:13:57 -04:00
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2009-12-30 18:37:13 +08:00
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2009-05-31 11:13:57 -04:00
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2010-02-05 12:08:31 +01:00
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2009-05-31 11:13:57 -04:00
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2009-12-30 18:37:13 +08:00
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2009-05-31 11:13:57 -04:00
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2009-12-30 18:37:13 +08:00
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2009-05-31 11:13:57 -04:00
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2008-11-26 12:03:55 +01:00
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2008-11-26 12:03:55 +01:00
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2009-05-31 11:13:57 -04:00
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2008-11-26 12:03:55 +01:00
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2009-01-26 15:00:59 +01:00
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2008-11-26 12:03:55 +01:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:54 -07:00
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2005-09-09 13:10:27 -07:00
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fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2005-09-09 13:10:27 -07:00
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fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2005-09-09 13:10:27 -07:00
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2008-11-26 12:03:55 +01:00
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fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2008-11-26 12:03:55 +01:00
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2005-09-09 13:10:27 -07:00
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2008-11-26 12:03:55 +01:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2006-01-16 22:14:41 -08:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:53 -07:00
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2006-04-10 22:54:55 -07:00
|
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|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2006-04-10 22:54:55 -07:00
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2006-01-16 22:14:25 -08:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:54 -07:00
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fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2006-06-25 05:48:54 -07:00
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2006-01-16 22:14:31 -08:00
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2005-09-09 13:10:27 -07:00
|
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|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
|
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|
2010-05-25 15:06:07 +02:00
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2006-04-10 22:54:55 -07:00
|
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|
|
2005-09-09 13:10:27 -07:00
|
|
|
|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:53 -07:00
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2005-09-09 13:10:27 -07:00
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2006-06-25 05:48:53 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
|
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|
2005-09-09 13:10:27 -07:00
|
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|
|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
|
|
|
|
2005-09-09 13:10:27 -07:00
|
|
|
|
|
|
|
|
|
|
|
|
|
|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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|
|
|
2010-05-25 15:06:07 +02:00
|
|
|
|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2010-05-25 15:06:07 +02:00
|
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|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2010-05-25 15:06:07 +02:00
|
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|
|
|
|
|
|
|
|
|
|
|
|
fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:50 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:50 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2006-04-10 22:54:50 -07:00
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2006-06-25 05:48:54 -07:00
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2006-04-10 22:54:50 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-01-16 22:14:41 -08:00
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2006-04-10 22:54:55 -07:00
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2006-01-16 22:14:41 -08:00
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2005-09-09 13:10:27 -07:00
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2008-12-02 14:49:42 +01:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-01-16 22:14:41 -08:00
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2006-06-25 05:48:53 -07:00
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2006-01-16 22:14:41 -08:00
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2006-01-16 22:14:42 -08:00
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2006-01-16 22:14:41 -08:00
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2008-12-02 14:49:42 +01:00
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2006-01-16 22:14:41 -08:00
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2006-01-16 22:14:42 -08:00
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2006-06-25 05:48:53 -07:00
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2006-01-16 22:14:41 -08:00
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2006-01-16 22:14:42 -08:00
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2006-04-10 22:54:55 -07:00
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2006-01-16 22:14:42 -08:00
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2008-11-26 12:03:54 +01:00
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2006-04-10 22:54:55 -07:00
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2006-01-16 22:14:42 -08:00
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2006-01-16 22:14:41 -08:00
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2006-06-25 05:48:53 -07:00
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2006-01-16 22:14:41 -08:00
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2006-04-10 22:54:55 -07:00
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2006-01-16 22:14:41 -08:00
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2006-06-25 05:48:50 -07:00
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2006-01-16 22:14:41 -08:00
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2006-06-25 05:48:50 -07:00
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2006-04-10 22:54:52 -07:00
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2006-01-16 22:14:41 -08:00
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2006-04-10 22:54:55 -07:00
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2006-01-16 22:14:41 -08:00
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2009-04-14 10:54:53 +09:00
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2006-01-16 22:14:41 -08:00
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2009-04-14 10:54:53 +09:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2005-09-09 13:10:31 -07:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:55 -07:00
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2006-06-25 05:48:51 -07:00
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2006-04-10 22:54:52 -07:00
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2006-01-16 22:14:35 -08:00
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2005-09-09 13:10:27 -07:00
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2009-04-14 10:54:53 +09:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:52 -07:00
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2006-04-10 22:54:56 -07:00
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2006-04-10 22:54:52 -07:00
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2006-03-28 01:56:42 -08:00
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2005-09-09 13:10:27 -07:00
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2006-09-30 23:28:47 -07:00
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2010-05-25 15:06:07 +02:00
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2006-09-30 23:28:47 -07:00
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fuse: support splice() writing to fuse device
Allow userspace filesystem implementation to use splice() to write to
the fuse device. The semantics of using splice() are:
1) buffer the message header and data in a temporary pipe
2) with a *single* splice() call move the message from the temporary pipe
to the fuse device
The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer. It will
also allow zero copy moving of pages.
One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header. But the length of
the data transferred into the temporary pipe may not be known in
advance. The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):
struct fuse_out_header out;
iov.iov_base = &out;
iov.iov_len = sizeof(struct fuse_out_header);
vmsplice(pip[1], &iov, 1, 0);
len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
/* retrospectively modify the header: */
out.len = len + sizeof(struct fuse_out_header);
splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);
This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.
Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2010-05-25 15:06:06 +02:00
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2005-09-09 13:10:27 -07:00
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2006-04-10 22:54:52 -07:00
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2005-09-09 13:10:27 -07:00
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2009-04-14 10:54:53 +09:00
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2005-09-09 13:10:27 -07:00
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2007-07-20 10:11:58 +09:00
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2005-09-09 13:10:27 -07:00
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