linux.git/fs/xfs, branch v5.1

xfs: serialize unaligned dio writes against all other dio writes

2019-03-26T15:37:55+00:00

XFS applies more strict serialization constraints to unaligned
direct writes to accommodate things like direct I/O layer zeroing,
unwritten extent conversion, etc. Unaligned submissions acquire the
exclusive iolock and wait for in-flight dio to complete to ensure
multiple submissions do not race on the same block and cause data
corruption.

This generally works in the case of an aligned dio followed by an
unaligned dio, but the serialization is lost if I/Os occur in the
opposite order. If an unaligned write is submitted first and
immediately followed by an overlapping, aligned write, the latter
submits without the typical unaligned serialization barriers because
there is no indication of an unaligned dio still in-flight. This can
lead to unpredictable results.

To provide proper unaligned dio serialization, require that such
direct writes are always the only dio allowed in-flight at one time
for a particular inode. We already acquire the exclusive iolock and
drain pending dio before submitting the unaligned dio. Wait once
more after the dio submission to hold the iolock across the I/O and
prevent further submissions until the unaligned I/O completes. This
is heavy handed, but consistent with the current pre-submission
serialization for unaligned direct writes.

Signed-off-by: Brian Foster 
Reviewed-by: Allison Henderson 
Reviewed-by: Dave Chinner 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

xfs: prohibit fstrim in norecovery mode

2019-03-25T15:03:29+00:00

The xfs fstrim implementation uses the free space btrees to find free
space that can be discarded.  If we haven't recovered the log, the bnobt
will be stale and we absolutely *cannot* use stale metadata to zap the
underlying storage.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Eric Sandeen

xfs: always init bma in xfs_bmapi_write

2019-03-19T15:16:54+00:00

Always init the tp/ip fields of bma in xfs_bmapi_write so that the
bmapi_finish at the bottom never trips over null transaction or inode
pointers.

Coverity-id: 1443964
Signed-off-by: Darrick J. Wong 
Reviewed-by: Brian Foster

xfs: fix btree scrub checking with regards to root-in-inode

2019-03-19T15:16:41+00:00

In xchk_btree_check_owner, we can be passed a null buffer pointer.  This
should only happen for the root of a root-in-inode btree type, but we
should program defensively in case the btree cursor state ever gets
screwed up and we get a null buffer anyway.

Coverity-id: 1438713
Signed-off-by: Darrick J. Wong 
Reviewed-by: Brian Foster

xfs: dabtree scrub needs to range-check level

2019-03-19T15:16:21+00:00

Make sure scrub's dabtree iterator function checks that we're not
going deeper in the stack than our cursor permits.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Brian Foster

xfs: don't trip over uninitialized buffer on extent read of corrupted inode

2019-03-17T22:21:49+00:00

We've had rather rare reports of bmap btree block corruption where
the bmap root block has a level count of zero. The root cause of the
corruption is so far unknown. We do have verifier checks to detect
this form of on-disk corruption, but this doesn't cover a memory
corruption variant of the problem. The latter is a reasonable
possibility because the root block is part of the inode fork and can
reside in-core for some time before inode extents are read.

If this occurs, it leads to a system crash such as the following:

 BUG: unable to handle kernel paging request at ffffffff00000221
 PF error: [normal kernel read fault]
 ...
 RIP: 0010:xfs_trans_brelse+0xf/0x200 [xfs]
 ...
 Call Trace:
  xfs_iread_extents+0x379/0x540 [xfs]
  xfs_file_iomap_begin_delay+0x11a/0xb40 [xfs]
  ? xfs_attr_get+0xd1/0x120 [xfs]
  ? iomap_write_begin.constprop.40+0x2d0/0x2d0
  xfs_file_iomap_begin+0x4c4/0x6d0 [xfs]
  ? __vfs_getxattr+0x53/0x70
  ? iomap_write_begin.constprop.40+0x2d0/0x2d0
  iomap_apply+0x63/0x130
  ? iomap_write_begin.constprop.40+0x2d0/0x2d0
  iomap_file_buffered_write+0x62/0x90
  ? iomap_write_begin.constprop.40+0x2d0/0x2d0
  xfs_file_buffered_aio_write+0xe4/0x3b0 [xfs]
  __vfs_write+0x150/0x1b0
  vfs_write+0xba/0x1c0
  ksys_pwrite64+0x64/0xa0
  do_syscall_64+0x5a/0x1d0
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

The crash occurs because xfs_iread_extents() attempts to release an
uninitialized buffer pointer as the level == 0 value prevented the
buffer from ever being allocated or read. Change the level > 0
assert to an explicit error check in xfs_iread_extents() to avoid
crashing the kernel in the event of localized, in-core inode
corruption.

Signed-off-by: Brian Foster 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

Merge tag 'xfs-5.1-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

2019-03-15T20:55:30+00:00

Pull xfs cleanups from Darrick Wong:
 "Here's a few more cleanups that trickled in for the merge window.

  It's all fixes for static checker complaints and slowly unwinding
  typedef usage. The four patches here have gone through a few days
  worth of fstest runs with no new problems observed.

  Summary:

   - Fix some clang/smatch/sparse warnings about uninitialized
     variables.

   - Clean up some typedef usage"

* tag 'xfs-5.1-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: clean up xfs_dir2_leaf_addname
  xfs: zero initialize highstale and lowstale in xfs_dir2_leaf_addname
  xfs: clean up xfs_dir2_leafn_add
  xfs: Zero initialize highstale and lowstale in xfs_dir2_leafn_add

xfs: clean up xfs_dir2_leaf_addname

2019-03-12T16:19:38+00:00

Remove typedefs and consolidate local variable initialization.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Allison Henderson 
Reviewed-by: Bill O'Donnell

xfs: zero initialize highstale and lowstale in xfs_dir2_leaf_addname

2019-03-10T18:41:31+00:00

Smatch complains about the following:

fs/xfs/libxfs/xfs_dir2_leaf.c:848 xfs_dir2_leaf_addname() error:
uninitialized symbol 'lowstale'.

fs/xfs/libxfs/xfs_dir2_leaf.c:849 xfs_dir2_leaf_addname() error:
uninitialized symbol 'highstale'.

I don't think there's any incorrect behavior associated with the
uninitialized variable, but as the author of the previous zero-init
patch points out, it's best not to be passing around pointers to
uninitialized stack areas.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Nathan Chancellor 
Reviewed-by: Allison Henderson 
Reviewed-by: Bill O'Donnell

xfs: clean up xfs_dir2_leafn_add

2019-03-08T22:24:43+00:00

Remove typedefs and consolidate local variable initialization.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Nick Desaulniers