Commit Graph

3119 Commits

Author SHA1 Message Date
Christoph Hellwig
c977eb1065 xfs: split xfs_bmap_btalloc_nullfb
Split xfs_bmap_btalloc_nullfb into one function for filestream allocations
and one for everything else that share a few helpers.  This dramatically
simplifies the control flow.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-04-23 07:11:41 +10:00
Christoph Hellwig
8b90a33f47 xfs: don't try to use the filestream allocator for metadata allocations
xfs_bmap_btalloc_nullfb has two entirely different control flows when
using the filestream allocator vs the regular one, but it get the
conditionals wrong and ends up mixing the two for metadata allocations.
Fix this by adding a missing userdata check and slight refactoring.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-04-14 19:37:42 +10:00
Linus Torvalds
5166701b36 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
 "The first vfs pile, with deep apologies for being very late in this
  window.

  Assorted cleanups and fixes, plus a large preparatory part of iov_iter
  work.  There's a lot more of that, but it'll probably go into the next
  merge window - it *does* shape up nicely, removes a lot of
  boilerplate, gets rid of locking inconsistencie between aio_write and
  splice_write and I hope to get Kent's direct-io rewrite merged into
  the same queue, but some of the stuff after this point is having
  (mostly trivial) conflicts with the things already merged into
  mainline and with some I want more testing.

  This one passes LTP and xfstests without regressions, in addition to
  usual beating.  BTW, readahead02 in ltp syscalls testsuite has started
  giving failures since "mm/readahead.c: fix readahead failure for
  memoryless NUMA nodes and limit readahead pages" - might be a false
  positive, might be a real regression..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  missing bits of "splice: fix racy pipe->buffers uses"
  cifs: fix the race in cifs_writev()
  ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
  kill generic_file_buffered_write()
  ocfs2_file_aio_write(): switch to generic_perform_write()
  ceph_aio_write(): switch to generic_perform_write()
  xfs_file_buffered_aio_write(): switch to generic_perform_write()
  export generic_perform_write(), start getting rid of generic_file_buffer_write()
  generic_file_direct_write(): get rid of ppos argument
  btrfs_file_aio_write(): get rid of ppos
  kill the 5th argument of generic_file_buffered_write()
  kill the 4th argument of __generic_file_aio_write()
  lustre: don't open-code kernel_recvmsg()
  ocfs2: don't open-code kernel_recvmsg()
  drbd: don't open-code kernel_recvmsg()
  constify blk_rq_map_user_iov() and friends
  lustre: switch to kernel_sendmsg()
  ocfs2: don't open-code kernel_sendmsg()
  take iov_iter stuff to mm/iov_iter.c
  process_vm_access: tidy up a bit
  ...
2014-04-12 14:49:50 -07:00
Kirill A. Shutemov
f1820361f8 mm: implement ->map_pages for page cache
filemap_map_pages() is generic implementation of ->map_pages() for
filesystems who uses page cache.

It should be safe to use filemap_map_pages() for ->map_pages() if
filesystem use filemap_fault() for ->fault().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ning Qu <quning@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:35:53 -07:00
Linus Torvalds
d15e03104e xfs: update for 3.15-rc1
The main changes in the XFS tree for 3.15-rc1 are:
 
         - O_TMPFILE support
         - allowing AIO+DIO writes beyond EOF
         - FALLOC_FL_COLLAPSE_RANGE support for fallocate syscall and XFS
           implementation
         - FALLOC_FL_ZERO_RANGE support for fallocate syscall and XFS
           implementation
         - IO verifier cleanup and rework
         - stack usage reduction changes
         - vm_map_ram NOIO context fixes to remove lockdep warings
         - various bug fixes and cleanups
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.12 (GNU/Linux)
 
 iQIcBAABAgAGBQJTPykMAAoJEK3oKUf0dfod/KoP/jKQwzQPdtT8EtAu5vENh9AO
 55zwCDXXFjCNIGIFPkrUBQbbARVAqhLZn3vuLUUhqtRRELdgJy/yFKZ37MPd8bhU
 dKetivEB192Jcd6Sn74vsOsNLm1u9mJqbQ1aothz0TiOrkkWFZlz4Otu36MZRHN3
 9WgZXWSxr6I/hYHGyCorJWZ5ISs0XD3vR5dYXYeZChbTpTxlCT4X/YgUtW4WH/Tq
 y4gG0fKfwr9KK07/LXuQgUuZGU8vwVuNNsXPhqh+FZ39SLD2Ea83h46Hzf/+vVNI
 kCIyYN1y40uBWczmwAptVEnUwhpGK8PzNrhKwTZICDtuct9sikf7c+o0aEE9lcqo
 8IBt0Dy4l7BQVFSZOjYo5Jw5a8jAbkh47zru31HxogEVqafdz80iWB12JagOOnXM
 v/McvDvZMyfgGckih32FM4G7ElvTYgGai5/3dLhfMuhc4/DdwcBOF1yHmFmnjhWO
 QRsQxLdefUtP3MfMYKaJHM6v2wE1S2l0owgp+HdPluNiOUmH/fqFq1WpHxqqeRPz
 nuHF8oYlxaZP5WAarz6Yf1/twIeZJ1rTD8np8uocvMqQJzMYJgrQyH+xJqjJaITR
 iveQcEoRB8D7/fXMGDdcjZYE2fG4l4JE2kuh97k5NZw76e3v2YXSGh0kd9WqR1uN
 t07joLRQKR2pJuSmuD5E
 =uSkJ
 -----END PGP SIGNATURE-----

Merge tag 'xfs-for-linus-3.15-rc1' of git://oss.sgi.com/xfs/xfs

Pull xfs update from Dave Chinner:
 "There are a couple of new fallocate features in this request - it was
  decided that it was easiest to push them through the XFS tree using
  topic branches and have the ext4 support be based on those branches.
  Hence you may see some overlap with the ext4 tree merge depending on
  how they including those topic branches into their tree.  Other than
  that, there is O_TMPFILE support, some cleanups and bug fixes.

  The main changes in the XFS tree for 3.15-rc1 are:

   - O_TMPFILE support
   - allowing AIO+DIO writes beyond EOF
   - FALLOC_FL_COLLAPSE_RANGE support for fallocate syscall and XFS
     implementation
   - FALLOC_FL_ZERO_RANGE support for fallocate syscall and XFS
     implementation
   - IO verifier cleanup and rework
   - stack usage reduction changes
   - vm_map_ram NOIO context fixes to remove lockdep warings
   - various bug fixes and cleanups"

* tag 'xfs-for-linus-3.15-rc1' of git://oss.sgi.com/xfs/xfs: (34 commits)
  xfs: fix directory hash ordering bug
  xfs: extra semi-colon breaks a condition
  xfs: Add support for FALLOC_FL_ZERO_RANGE
  fs: Introduce FALLOC_FL_ZERO_RANGE flag for fallocate
  xfs: inode log reservations are still too small
  xfs: xfs_check_page_type buffer checks need help
  xfs: avoid AGI/AGF deadlock scenario for inode chunk allocation
  xfs: use NOIO contexts for vm_map_ram
  xfs: don't leak EFSBADCRC to userspace
  xfs: fix directory inode iolock lockdep false positive
  xfs: allocate xfs_da_args to reduce stack footprint
  xfs: always do log forces via the workqueue
  xfs: modify verifiers to differentiate CRC from other errors
  xfs: print useful caller information in xfs_error_report
  xfs: add xfs_verifier_error()
  xfs: add helper for updating checksums on xfs_bufs
  xfs: add helper for verifying checksums on xfs_bufs
  xfs: Use defines for CRC offsets in all cases
  xfs: skip pointless CRC updates after verifier failures
  xfs: Add support FALLOC_FL_COLLAPSE_RANGE for fallocate
  ...
2014-04-04 15:50:08 -07:00
Linus Torvalds
24e7ea3bea Major changes for 3.14 include support for the newly added ZERO_RANGE
and COLLAPSE_RANGE fallocate operations, and scalability improvements
 in the jbd2 layer and in xattr handling when the extended attributes
 spill over into an external block.
 
 Other than that, the usual clean ups and minor bug fixes.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.22 (GNU/Linux)
 
 iQIcBAABCAAGBQJTPbD2AAoJENNvdpvBGATwDmUQANSfGYIQazB8XKKgtNTMiG/Y
 Ky7n1JzN9lTX/6nMsqQnbfCweLRmxqpWUBuyKDRHUi8IG0/voXSTFsAOOgz0R15A
 ERRRWkVvHixLpohuL/iBdEMFHwNZYPGr3jkm0EIgzhtXNgk5DNmiuMwvHmCY27kI
 kdNZIw9fip/WRNoFLDBGnLGC37aanoHhCIbVlySy5o9LN1pkC8BgXAYV0Rk19SVd
 bWCudSJEirFEqWS5H8vsBAEm/ioxTjwnNL8tX8qms6orZ6h8yMLFkHoIGWPw3Q15
 a0TSUoMyav50Yr59QaDeWx9uaPQVeK41wiYFI2rZOnyG2ts0u0YXs/nLwJqTovgs
 rzvbdl6cd3Nj++rPi97MTA7iXK96WQPjsDJoeeEgnB0d/qPyTk6mLKgftzLTNgSa
 ZmWjrB19kr6CMbebMC4L6eqJ8Fr66pCT8c/iue8wc4MUHi7FwHKH64fqWvzp2YT/
 +165dqqo2JnUv7tIp6sUi1geun+bmDHLZFXgFa7fNYFtcU3I+uY1mRr3eMVAJndA
 2d6ASe/KhQbpVnjKJdQ8/b833ZS3p+zkgVPrd68bBr3t7gUmX91wk+p1ct6rUPLr
 700F+q/pQWL8ap0pU9Ht/h3gEJIfmRzTwxlOeYyOwDseqKuS87PSB3BzV3dDunSU
 DrPKlXwIgva7zq5/S0Vr
 =4s1Z
 -----END PGP SIGNATURE-----

Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "Major changes for 3.14 include support for the newly added ZERO_RANGE
  and COLLAPSE_RANGE fallocate operations, and scalability improvements
  in the jbd2 layer and in xattr handling when the extended attributes
  spill over into an external block.

  Other than that, the usual clean ups and minor bug fixes"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (42 commits)
  ext4: fix premature freeing of partial clusters split across leaf blocks
  ext4: remove unneeded test of ret variable
  ext4: fix comment typo
  ext4: make ext4_block_zero_page_range static
  ext4: atomically set inode->i_flags in ext4_set_inode_flags()
  ext4: optimize Hurd tests when reading/writing inodes
  ext4: kill i_version support for Hurd-castrated file systems
  ext4: each filesystem creates and uses its own mb_cache
  fs/mbcache.c: doucple the locking of local from global data
  fs/mbcache.c: change block and index hash chain to hlist_bl_node
  ext4: Introduce FALLOC_FL_ZERO_RANGE flag for fallocate
  ext4: refactor ext4_fallocate code
  ext4: Update inode i_size after the preallocation
  ext4: fix partial cluster handling for bigalloc file systems
  ext4: delete path dealloc code in ext4_ext_handle_uninitialized_extents
  ext4: only call sync_filesystm() when remounting read-only
  fs: push sync_filesystem() down to the file system's remount_fs()
  jbd2: improve error messages for inconsistent journal heads
  jbd2: minimize region locked by j_list_lock in jbd2_journal_forget()
  jbd2: minimize region locked by j_list_lock in journal_get_create_access()
  ...
2014-04-04 15:39:39 -07:00
Johannes Weiner
91b0abe36a mm + fs: store shadow entries in page cache
Reclaim will be leaving shadow entries in the page cache radix tree upon
evicting the real page.  As those pages are found from the LRU, an
iput() can lead to the inode being freed concurrently.  At this point,
reclaim must no longer install shadow pages because the inode freeing
code needs to ensure the page tree is really empty.

Add an address_space flag, AS_EXITING, that the inode freeing code sets
under the tree lock before doing the final truncate.  Reclaim will check
for this flag before installing shadow pages.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Metin Doslu <metin@citusdata.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ozgun Erdogan <ozgun@citusdata.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03 16:21:01 -07:00
Dave Chinner
a6cf33bc56 Merge branch 'xfs-bug-fixes-for-3.15-3' into for-next 2014-04-04 08:07:35 +11:00
Mark Tinguely
c88547a811 xfs: fix directory hash ordering bug
Commit f5ea1100 ("xfs: add CRCs to dir2/da node blocks") introduced
in 3.10 incorrectly converted the btree hash index array pointer in
xfs_da3_fixhashpath(). It resulted in the the current hash always
being compared against the first entry in the btree rather than the
current block index into the btree block's hash entry array. As a
result, it was comparing the wrong hashes, and so could misorder the
entries in the btree.

For most cases, this doesn't cause any problems as it requires hash
collisions to expose the ordering problem. However, when there are
hash collisions within a directory there is a very good probability
that the entries will be ordered incorrectly and that actually
matters when duplicate hashes are placed into or removed from the
btree block hash entry array.

This bug results in an on-disk directory corruption and that results
in directory verifier functions throwing corruption warnings into
the logs. While no data or directory entries are lost, access to
them may be compromised, and attempts to remove entries from a
directory that has suffered from this corruption may result in a
filesystem shutdown.  xfs_repair will fix the directory hash
ordering without data loss occuring.

[dchinner: wrote useful a commit message]

cc: <stable@vger.kernel.org>
Reported-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-04-04 07:10:49 +11:00
Dan Carpenter
805eeb8e04 xfs: extra semi-colon breaks a condition
There were some extra semi-colons here which mean that we return true
unintentionally.

Fixes: a49935f200 ('xfs: xfs_check_page_type buffer checks need help')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-04-04 06:56:30 +11:00
Al Viro
0a64bc2c04 xfs_file_buffered_aio_write(): switch to generic_perform_write()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-04-01 23:19:36 -04:00
Al Viro
5cb6c6c7eb generic_file_direct_write(): get rid of ppos argument
always equal to &iocb->ki_pos.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-04-01 23:19:35 -04:00
Al Viro
fcacafd269 kill the 5th argument of generic_file_buffered_write()
same story - it's &iocb->ki_pos in all cases

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-04-01 23:19:34 -04:00
Al Viro
5d826c847b new helper: readlink_copy()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-04-01 23:19:15 -04:00
Theodore Ts'o
02b9984d64 fs: push sync_filesystem() down to the file system's remount_fs()
Previously, the no-op "mount -o mount /dev/xxx" operation when the
file system is already mounted read-write causes an implied,
unconditional syncfs().  This seems pretty stupid, and it's certainly
documented or guaraunteed to do this, nor is it particularly useful,
except in the case where the file system was mounted rw and is getting
remounted read-only.

However, it's possible that there might be some file systems that are
actually depending on this behavior.  In most file systems, it's
probably fine to only call sync_filesystem() when transitioning from
read-write to read-only, and there are some file systems where this is
not needed at all (for example, for a pseudo-filesystem or something
like romfs).

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: linux-fsdevel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Cc: Jan Kara <jack@suse.cz>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Anders Larsen <al@alarsen.net>
Cc: Phillip Lougher <phillip@squashfs.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Cc: Petr Vandrovec <petr@vandrovec.name>
Cc: xfs@oss.sgi.com
Cc: linux-btrfs@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Cc: codalist@coda.cs.cmu.edu
Cc: linux-ext4@vger.kernel.org
Cc: linux-f2fs-devel@lists.sourceforge.net
Cc: fuse-devel@lists.sourceforge.net
Cc: cluster-devel@redhat.com
Cc: linux-mtd@lists.infradead.org
Cc: jfs-discussion@lists.sourceforge.net
Cc: linux-nfs@vger.kernel.org
Cc: linux-nilfs@vger.kernel.org
Cc: linux-ntfs-dev@lists.sourceforge.net
Cc: ocfs2-devel@oss.oracle.com
Cc: reiserfs-devel@vger.kernel.org
2014-03-13 10:14:33 -04:00
Dave Chinner
fe986f9d88 Merge branch 'xfs-O_TMPFILE-support' into for-next
Conflicts:
	fs/xfs/xfs_trans_resv.c
	- fix for XFS_INODE_CLUSTER_SIZE macro removal
2014-03-13 19:14:43 +11:00
Dave Chinner
5f44e4c185 Merge branch 'xfs-bug-fixes-for-3.15-2' into for-next 2014-03-13 19:13:05 +11:00
Dave Chinner
49ae4b97d7 Merge branch 'xfs-verifier-cleanup' into for-next 2014-03-13 19:12:33 +11:00
Dave Chinner
730357a5cb Merge branch 'xfs-stack-fixes' into for-next 2014-03-13 19:12:13 +11:00
Dave Chinner
b6db0551fd Merge branch 'xfs-collapse-range' into for-next 2014-03-13 19:11:06 +11:00
Lukas Czerner
376ba31314 xfs: Add support for FALLOC_FL_ZERO_RANGE
Introduce new FALLOC_FL_ZERO_RANGE flag for fallocate. This has the same
functionality as xfs ioctl XFS_IOC_ZERO_RANGE.

We can also preallocate blocks past EOF in the same was as with
fallocate. Flag FALLOC_FL_KEEP_SIZE will cause the inode size to remain
the same even if we preallocate blocks past EOF.

It uses the same code to zero range as it is used by the
XFS_IOC_ZERO_RANGE ioctl.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-13 19:07:58 +11:00
Dave Chinner
fe4c224aa1 xfs: inode log reservations are still too small
Back in commit 23956703 ("xfs: inode log reservations are too
small"), the reservation size was increased to take into account the
difference in size between the in-memory BMBT block headers and the
on-disk BMDR headers. This solved a transaction overrun when logging
the inode size.

Recently, however, we've seen a number of these same overruns on
kernels with the above fix in it. All of them have been by 4 bytes,
so we must still not be accounting for something correctly.

Through inspection it turns out the above commit didn't take into
account everything it should have. That is, it only accounts for a
single log op_hdr structure, when it can actually require up to four
op_hdrs - one for each region (log iovec) that is formatted. These
regions are the inode log format header, the inode core, and the two
forks that can be held in the literal area of the inode.

This means we are not accounting for 36 bytes of log space that the
transaction can use, and hence when we get inodes in certain formats
with particular fragmentation patterns we can overrun the
transaction. Fix this by adding the correct accounting for log
op_headers in the transaction.

Tested-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 16:19:14 +11:00
Dave Chinner
a49935f200 xfs: xfs_check_page_type buffer checks need help
xfs_aops_discard_page() was introduced in the following commit:

  xfs: truncate delalloc extents when IO fails in writeback

... to clean up left over delalloc ranges after I/O failure in
->writepage(). generic/224 tests for this scenario and occasionally
reproduces panics on sub-4k blocksize filesystems.

The cause of this is failure to clean up the delalloc range on a
page where the first buffer does not match one of the expected
states of xfs_check_page_type(). If a buffer is not unwritten,
delayed or dirty&mapped, xfs_check_page_type() stops and
immediately returns 0.

The stress test of generic/224 creates a scenario where the first
several buffers of a page with delayed buffers are mapped & uptodate
and some subsequent buffer is delayed. If the ->writepage() happens
to fail for this page, xfs_aops_discard_page() incorrectly skips
the entire page.

This then causes later failures either when direct IO maps the range
and finds the stale delayed buffer, or we evict the inode and find
that the inode still has a delayed block reservation accounted to
it.

We can easily fix this xfs_aops_discard_page() failure by making
xfs_check_page_type() check all buffers, but this breaks
xfs_convert_page() more than it is already broken. Indeed,
xfs_convert_page() wants xfs_check_page_type() to tell it if the
first buffers on the pages are of a type that can be aggregated into
the contiguous IO that is already being built.

xfs_convert_page() should not be writing random buffers out of a
page, but the current behaviour will cause it to do so if there are
buffers that don't match the current specification on the page.
Hence for xfs_convert_page() we need to:

	a) return "not ok" if the first buffer on the page does not
	match the specification provided to we don't write anything;
	and
	b) abort it's buffer-add-to-io loop the moment we come
	across a buffer that does not match the specification.

Hence we need to fix both xfs_check_page_type() and
xfs_convert_page() to work correctly with pages that have mixed
buffer types, whilst allowing xfs_aops_discard_page() to scan all
buffers on the page for a type match.

Reported-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 16:19:14 +11:00
Brian Foster
e480a72397 xfs: avoid AGI/AGF deadlock scenario for inode chunk allocation
The inode chunk allocation path can lead to deadlock conditions if
a transaction is dirtied with an AGF (to fix up the freelist) for
an AG that cannot satisfy the actual allocation request. This code
path is written to try and avoid this scenario, but it can be
reproduced by running xfstests generic/270 in a loop on a 512b fs.

An example situation is:
- process A attempts an inode allocation on AG 3, modifies
  the freelist, fails the allocation and ultimately moves on to
  AG 0 with the AG 3 AGF held
- process B is doing a free space operation (i.e., truncate) and
  acquires the AG 0 AGF, waits on the AG 3 AGF
- process A acquires the AG 0 AGI, waits on the AG 0 AGF (deadlock)

The problem here is that process A acquired the AG 3 AGF while
moving on to AG 0 (and releasing the AG 3 AGI with the AG 3 AGF
held). xfs_dialloc() makes one pass through each of the AGs when
attempting to allocate an inode chunk. The expectation is a clean
transaction if a particular AG cannot satisfy the allocation
request. xfs_ialloc_ag_alloc() is written to support this through
use of the minalignslop allocation args field.

When using the agi->agi_newino optimization, we attempt an exact
bno allocation request based on the location of the previously
allocated chunk. minalignslop is set to inform the allocator that
we will require alignment on this chunk, and thus to not allow the
request for this AG if the extra space is not available. Suppose
that the AG in question has just enough space for this request, but
not at the requested bno. xfs_alloc_fix_freelist() will proceed as
normal as it determines the request should succeed, and thus it is
allowed to modify the agf. xfs_alloc_ag_vextent() ultimately fails
because the requested bno is not available. In response, the caller
moves on to a NEAR_BNO allocation request for the same AG. The
alignment is set, but the minalignslop field is never reset. This
increases the overall requirement of the request from the first
attempt. If this delta is the difference between allocation success
and failure for the AG, xfs_alloc_fix_freelist() rejects this
request outright the second time around and causes the allocation
request to unnecessarily fail for this AG.

To address this situation, reset the minalignslop field immediately
after use and prevent it from leaking into subsequent requests.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 16:19:14 +11:00
Dave Chinner
ae687e58b3 xfs: use NOIO contexts for vm_map_ram
When we map pages in the buffer cache, we can do so in GFP_NOFS
contexts. However, the vmap interfaces do not provide any method of
communicating this information to memory reclaim, and hence we get
lockdep complaining about it regularly and occassionally see hangs
that may be vmap related reclaim deadlocks. We can also see these
same problems from anywhere where we use vmalloc for a large buffer
(e.g. attribute code) inside a transaction context.

A typical lockdep report shows up as a reclaim state warning like so:

[14046.101458] =================================
[14046.102850] [ INFO: inconsistent lock state ]
[14046.102850] 3.14.0-rc4+ #2 Not tainted
[14046.102850] ---------------------------------
[14046.102850] inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
[14046.102850] kswapd0/14 [HC0[0]:SC0[0]:HE1:SE1] takes:
[14046.102850]  (&xfs_dir_ilock_class){++++?+}, at: [<791a04bb>] xfs_ilock+0xff/0x16a
[14046.102850] {RECLAIM_FS-ON-W} state was registered at:
[14046.102850]   [<7904cdb1>] mark_held_locks+0x81/0xe7
[14046.102850]   [<7904d390>] lockdep_trace_alloc+0x5c/0xb4
[14046.102850]   [<790c2c28>] kmem_cache_alloc_trace+0x2b/0x11e
[14046.102850]   [<790ba7f4>] vm_map_ram+0x119/0x3e6
[14046.102850]   [<7914e124>] _xfs_buf_map_pages+0x5b/0xcf
[14046.102850]   [<7914ed74>] xfs_buf_get_map+0x67/0x13f
[14046.102850]   [<7917506f>] xfs_attr_rmtval_set+0x396/0x4d5
[14046.102850]   [<7916e8bb>] xfs_attr_leaf_addname+0x18f/0x37d
[14046.102850]   [<7916ed9e>] xfs_attr_set_int+0x2f5/0x3e8
[14046.102850]   [<7916eefc>] xfs_attr_set+0x6b/0x74
[14046.102850]   [<79168355>] xfs_xattr_set+0x61/0x81
[14046.102850]   [<790e5b10>] generic_setxattr+0x59/0x68
[14046.102850]   [<790e4c06>] __vfs_setxattr_noperm+0x58/0xce
[14046.102850]   [<790e4d0a>] vfs_setxattr+0x8e/0x92
[14046.102850]   [<790e4ddd>] setxattr+0xcf/0x159
[14046.102850]   [<790e5423>] SyS_lsetxattr+0x88/0xbb
[14046.102850]   [<79268438>] sysenter_do_call+0x12/0x36

Now, we can't completely remove these traces - mainly because
vm_map_ram() will do GFP_KERNEL allocation and that generates the
above warning before we get into the reclaim code, but we can turn
them all into false positive warnings.

To do that, use the method that DM and other IO context code uses to
avoid this problem: there is a process flag to tell memory reclaim
not to do IO that we can set appropriately. That prevents GFP_KERNEL
context reclaim being done from deep inside the vmalloc code in
places we can't directly pass a GFP_NOFS context to. That interface
has a pair of wrapper functions: memalloc_noio_save() and
memalloc_noio_restore().

Adding them around vm_map_ram and the vzalloc call in
kmem_alloc_large() will prevent deadlocks and most lockdep reports
for this issue. Also, convert the vzalloc() call in
kmem_alloc_large() to use __vmalloc() so that we can pass the
correct gfp context to the data page allocation routine inside
__vmalloc() so that it is clear that GFP_NOFS context is important
to this vmalloc call.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 16:19:14 +11:00
Dave Chinner
ac75a1f7a4 xfs: don't leak EFSBADCRC to userspace
While the verifier routines may return EFSBADCRC when a buffer has
a bad CRC, we need to translate that to EFSCORRUPTED so that the
higher layers treat the error appropriately and we return a
consistent error to userspace. This fixes a xfs/005 regression.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-03-07 16:19:14 +11:00
Linus Torvalds
8d7531825c Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull filesystem fixes from Jan Kara:
 "Notification, writeback, udf, quota fixes

  The notification patches are (with one exception) a fallout of my
  fsnotify rework which went into -rc1 (I've extented LTP to cover these
  cornercases to avoid similar breakage in future).

  The UDF patch is a nasty data corruption Al has recently reported,
  the revert of the writeback patch is due to possibility of violating
  sync(2) guarantees, and a quota bug can lead to corruption of quota
  files in ocfs2"

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fsnotify: Allocate overflow events with proper type
  fanotify: Handle overflow in case of permission events
  fsnotify: Fix detection whether overflow event is queued
  Revert "writeback: do not sync data dirtied after sync start"
  quota: Fix race between dqput() and dquot_scan_active()
  udf: Fix data corruption on file type conversion
  inotify: Fix reporting of cookies for inotify events
2014-02-27 10:37:22 -08:00
Dave Chinner
93a8614e3a xfs: fix directory inode iolock lockdep false positive
The change to add the IO lock to protect the directory extent map
during readdir operations has cause lockdep to have a heart attack
as it now sees a different locking order on inodes w.r.t. the
mmap_sem because readdir has a different ordering to write().

Add a new lockdep class for directory inodes to avoid this false
positive.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 16:51:39 +11:00
Dave Chinner
a1358aa3d3 xfs: allocate xfs_da_args to reduce stack footprint
The struct xfs_da_args used to pass directory/attribute operation
information to the lower layers is 128 bytes in size and is
allocated on the stack. Dynamically allocate them to reduce the
stack footprint of directory operations.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 16:51:26 +11:00
Dave Chinner
f876e44603 xfs: always do log forces via the workqueue
Log forces can occur deep in the call chain when we have relatively
little stack free. Log forces can also happen at close to the call
chain leaves (e.g. xfs_buf_lock()) and hence we can trigger IO from
places where we really don't want to add more stack overhead.

This stack overhead occurs because log forces do foreground CIL
pushes (xlog_cil_push_foreground()) rather than waking the
background push wq and waiting for the for the push to complete.
This foreground push was done to avoid confusing the CFQ Io
scheduler when fsync()s were issued, as it has trouble dealing with
dependent IOs being issued from different process contexts.

Avoiding blowing the stack is much more critical than performance
optimisations for CFQ, especially as we've been recommending against
the use of CFQ for XFS since 3.2 kernels were release because of
it's problems with multi-threaded IO workloads.

Hence convert xlog_cil_push_foreground() to move the push work
to the CIL workqueue. We already do the waiting for the push to
complete in xlog_cil_force_lsn(), so there's nothing else we need to
modify to make this work.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 16:40:42 +11:00
Eric Sandeen
ce5028cfe3 xfs: modify verifiers to differentiate CRC from other errors
Modify all read & write verifiers to differentiate
between CRC errors and other inconsistencies.

This sets the appropriate error number on bp->b_error,
and then calls xfs_verifier_error() if something went
wrong.  That function will issue the appropriate message
to the user.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 15:23:10 +11:00
Eric Sandeen
db9355c296 xfs: print useful caller information in xfs_error_report
xfs_error_report used to just print the hex address of the caller;
%pF will give us something more human-readable.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 15:21:37 +11:00
Eric Sandeen
ca23f8fdd6 xfs: add xfs_verifier_error()
We want to distinguish between corruption, CRC errors,
etc.  In addition, the full stack trace on verifier errors
seems less than helpful; it looks more like an oops than
corruption.

Create a new function to specifically alert the user to
verifier errors, which can differentiate between
EFSCORRUPTED and CRC mismatches.  It doesn't dump stack
unless the xfs error level is turned up high.

Define a new error message (EFSBADCRC) to clearly identify
CRC errors.  (Defined to EBADMSG, bad message)

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 15:21:07 +11:00
Eric Sandeen
f1dbcd7e38 xfs: add helper for updating checksums on xfs_bufs
Many/most callers of xfs_update_cksum() pass bp->b_addr and
BBTOB(bp->b_length) as the first 2 args.  Add a helper
which can just accept the bp and the crc offset, and work
it out on its own, for brevity.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 15:18:23 +11:00
Eric Sandeen
5158217058 xfs: add helper for verifying checksums on xfs_bufs
Many/most callers of xfs_verify_cksum() pass bp->b_addr and
BBTOB(bp->b_length) as the first 2 args.  Add a helper
which can just accept the bp and the crc offset, and work
it out on its own, for brevity.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 15:17:27 +11:00
Eric Sandeen
533b81c875 xfs: Use defines for CRC offsets in all cases
Some calls to crc functions used useful #defines,
others used awkward offsetof() constructs.

Switch them all to #define to make things a bit cleaner.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 15:15:27 +11:00
Eric Sandeen
e0d2c23a25 xfs: skip pointless CRC updates after verifier failures
Most write verifiers don't update CRCs after the verifier
has failed and the buffer has been marked in error.  These
two didn't, but should.

Add returns to the verifier failure block, since the buffer
won't be written anyway.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 15:14:31 +11:00
Namjae Jeon
e1d8fb88a6 xfs: Add support FALLOC_FL_COLLAPSE_RANGE for fallocate
This patch implements fallocate's FALLOC_FL_COLLAPSE_RANGE for XFS.

The semantics of this flag are following:
1) It collapses the range lying between offset and length by removing any data
   blocks which are present in this range and than updates all the logical
   offsets of extents beyond "offset + len" to nullify the hole created by
   removing blocks. In short, it does not leave a hole.
2) It should be used exclusively. No other fallocate flag in combination.
3) Offset and length supplied to fallocate should be fs block size aligned
   in case of xfs and ext4.
4) Collaspe range does not work beyond i_size.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-24 10:58:19 +11:00
Linus Torvalds
645ceee885 Merge branch 'xfs-fixes-for-3.14-rc4' of git://oss.sgi.com/xfs/xfs
Pull xfs fixes from Dave Chinner:
 "This is the first pull request I've had to do for you, so I'm still
  sorting things out.  The reason I'm sending this and not Ben should be
  obvious from the first commit below - SGI has stepped down from the
  XFS maintainership role.  As such, I'd like to take another
  opportunity to thank them for their many years of effort maintaining
  XFS and supporting the XFS community that they developed from the
  ground up.

  So I haven't had time to work things like signed tags into my
  workflows yet, so this is just a repo branch I'm asking you to pull
  from.  And yes, I named the branch -rc4 because I wanted the fixes in
  rc4, not because the branch was for merging into -rc3.  Probably not
  right, either.

  Anyway, I should have everything sorted out by the time the next merge
  window comes around.  If there's anything that you don't like in the
  pull req, feel free to flame me unmercifully.

  The changes are fixes for recent regressions and important thinkos in
  verification code:

        - a log vector buffer alignment issue on ia32
        - timestamps on truncate got mangled
        - primary superblock CRC validation fixes and error message
          sanitisation"

* 'xfs-fixes-for-3.14-rc4' of git://oss.sgi.com/xfs/xfs:
  xfs: limit superblock corruption errors to actual corruption
  xfs: skip verification on initial "guess" superblock read
  MAINTAINERS: SGI no longer maintaining XFS
  xfs: xfs_sb_read_verify() doesn't flag bad crcs on primary sb
  xfs: ensure correct log item buffer alignment
  xfs: ensure correct timestamp updates from truncate
2014-02-22 08:26:01 -08:00
Jan Kara
0dc83bd30b Revert "writeback: do not sync data dirtied after sync start"
This reverts commit c4a391b53a. Dave
Chinner <david@fromorbit.com> has reported the commit may cause some
inodes to be left out from sync(2). This is because we can call
redirty_tail() for some inode (which sets i_dirtied_when to current time)
after sync(2) has started or similarly requeue_inode() can set
i_dirtied_when to current time if writeback had to skip some pages. The
real problem is in the functions clobbering i_dirtied_when but fixing
that isn't trivial so revert is a safer choice for now.

CC: stable@vger.kernel.org # >= 3.13
Signed-off-by: Jan Kara <jack@suse.cz>
2014-02-22 02:02:28 +01:00
Dave Chinner
027f185e66 Merge remote-tracking branch 'xfs-async-aio-extend' into for-next 2014-02-20 15:16:39 +11:00
Dave Chinner
b678573e29 Merge branch 'xfs-fixes-for-3.15' into for-next 2014-02-20 15:16:09 +11:00
Eric Sandeen
5ef11eb070 xfs: limit superblock corruption errors to actual corruption
Today, if

xfs_sb_read_verify
  xfs_sb_verify
    xfs_mount_validate_sb

detects superblock corruption, it'll be extremely noisy, dumping
2 stacks, 2 hexdumps, etc.

This is because we call XFS_CORRUPTION_ERROR in xfs_mount_validate_sb
as well as in xfs_sb_read_verify.

Also, *any* errors in xfs_mount_validate_sb which are not corruption
per se; things like too-big-blocksize, bad version, bad magic, v1 dirs,
rw-incompat etc - things which do not return EFSCORRUPTED - will
still do the whole XFS_CORRUPTION_ERROR spew when xfs_sb_read_verify
sees any error at all.  And it suggests to the user that they
should run xfs_repair, even if the root cause of the mount failure
is a simple incompatibility.

I'll submit that the probably-not-corrupted errors don't warrant
this much noise, so this patch removes the warning for anything
other than EFSCORRUPTED returns, and replaces the lower-level
XFS_CORRUPTION_ERROR with an xfs_notice().

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-19 15:39:35 +11:00
Eric Sandeen
daba5427da xfs: skip verification on initial "guess" superblock read
When xfs_readsb() does the very first read of the superblock,
it makes a guess at the length of the buffer, based on the
sector size of the underlying storage.  This may or may
not match the filesystem sector size in sb_sectsize, so
we can't i.e. do a CRC check on it; it might be too short.

In fact, mounting a filesystem with sb_sectsize larger
than the device sector size will cause a mount failure
if CRCs are enabled, because we are checksumming a length
which exceeds the buffer passed to it.

So always read twice; the first time we read with NULL
buffer ops to skip verification; then set the proper
read length, hook up the proper verifier, and give it
another go.

Once we are sure that we've got the right buffer length,
we can also use bp->b_length in the xfs_sb_read_verify,
rather than the less-trusted on-disk sectorsize for
secondary superblocks.  Before this we ran the risk of
passing junk to the crc32c routines, which didn't always
handle extreme values.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-19 15:39:16 +11:00
Eric Sandeen
7a01e707a3 xfs: xfs_sb_read_verify() doesn't flag bad crcs on primary sb
My earlier commit 10e6e65 deserves a layer or two of brown paper
bags.  The logic in that commit means that a CRC failure on the
primary superblock will *never* result in an error return.

Hopefully this fixes it, so that we always return the error
if it's a primary superblock, otherwise only if the filesystem
has CRCs enabled.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2014-02-19 15:33:05 +11:00
Dave Chinner
3895e51f6d xfs: ensure correct log item buffer alignment
On 32 bit platforms, the log item vector headers are not 64 bit
aligned or sized. hence if we don't take care to align them
correctly or pad the buffer appropriately for 8 byte alignment, we
can end up with alignment issues when accessing the user buffer
directly as a structure.

To solve this, simply pad the buffer headers to 64 bit offset so
that the data section is always 8 byte aligned.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reported-by: Michael L. Semon <mlsemon35@gmail.com>
Tested-by: Michael L. Semon <mlsemon35@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-10 10:37:18 +11:00
Christoph Hellwig
fe60a8a091 xfs: ensure correct timestamp updates from truncate
The VFS doesn't set the proper ATTR_CTIME and ATTR_MTIME values for
truncate, so filesystems have to manually add them.  The
introduction of xfs_setattr_time accidentally broke this special
case an caused a regression in generic/313.  Fix this by removing
the local mask variable in xfs_setattr_size so that we only have a
single place to keep the attribute information.

cc: <stable@vger.kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-10 10:35:22 +11:00
Christoph Hellwig
9862f62fab xfs: allow appending aio writes
XFS can easily support appending aio writes by ensuring we always allocate
blocks as unwritten extents when performing direct I/O writes and only
converting them to written extents at I/O completion.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-10 10:28:04 +11:00
Christoph Hellwig
d531d91d69 xfs: always use unwritten extents for direct I/O writes
To allow aio writes beyond i_size we need to create unwritten extents for
newly allocated blocks, similar to how we already do inside i_size.

Instead of adding another special case we now use unwritten extents
unconditionally.  This also marks the end of directly allocation data
extents in all of XFS - we now always use either delalloc or unwritten
extents.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-10 10:27:43 +11:00
Al Viro
d311d79de3 fix O_SYNC|O_APPEND syncing the wrong range on write()
It actually goes back to 2004 ([PATCH] Concurrent O_SYNC write support)
when sync_page_range() had been introduced; generic_file_write{,v}() correctly
synced
	pos_after_write - written .. pos_after_write - 1
but generic_file_aio_write() synced
	pos_before_write .. pos_before_write + written - 1
instead.  Which is not the same thing with O_APPEND, obviously.
A couple of years later correct variant had been killed off when
everything switched to use of generic_file_aio_write().

All users of generic_file_aio_write() are affected, and the same bug
has been copied into other instances of ->aio_write().

The fix is trivial; the only subtle point is that generic_write_sync()
ought to be inlined to avoid calculations useless for the majority of
calls.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-02-09 15:18:09 -05:00