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  1. 07 5月, 2020 1 次提交
  3. 27 3月, 2020 1 次提交
  5. 12 3月, 2020 2 次提交
  7. 03 3月, 2020 2 次提交
  9. 27 1月, 2020 5 次提交
  11. 19 11月, 2019 3 次提交
  13. 11 11月, 2019 1 次提交
  15. 30 10月, 2019 1 次提交
  17. 28 10月, 2019 1 次提交
  19. 07 10月, 2019 1 次提交
  21. 27 9月, 2019 1 次提交
  23. 27 8月, 2019 2 次提交
    • D
      xfs: add kmem_alloc_io() · f8f9ee47
      由 Dave Chinner 提交于 
      Memory we use to submit for IO needs strict alignment to the
underlying driver contraints. Worst case, this is 512 bytes. Given
that all allocations for IO are always a power of 2 multiple of 512
bytes, the kernel heap provides natural alignment for objects of
these sizes and that suffices.

Until, of course, memory debugging of some kind is turned on (e.g.
red zones, poisoning, KASAN) and then the alignment of the heap
objects is thrown out the window. Then we get weird IO errors and
data corruption problems because drivers don't validate alignment
and do the wrong thing when passed unaligned memory buffers in bios.

TO fix this, introduce kmem_alloc_io(), which will guaranteeat least
512 byte alignment of buffers for IO, even if memory debugging
options are turned on. It is assumed that the minimum allocation
size will be 512 bytes, and that sizes will be power of 2 mulitples
of 512 bytes.

Use this everywhere we allocate buffers for IO.

This no longer fails with log recovery errors when KASAN is enabled
due to the brd driver not handling unaligned memory buffers:

# mkfs.xfs -f /dev/ram0 ; mount /dev/ram0 /mnt/test
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
      f8f9ee47
    • T
      fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. · 707e0dda
      由 Tetsuo Handa 提交于 
      Since no caller is using KM_NOSLEEP and no callee branches on KM_SLEEP,
we can remove KM_NOSLEEP and replace KM_SLEEP with 0.
Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
      707e0dda
  25. 29 6月, 2019 6 次提交
  27. 12 6月, 2019 1 次提交
  29. 19 2月, 2019 1 次提交
  31. 12 2月, 2019 2 次提交
    • B
      xfs: distinguish between inobt and finobt magic values · 8473fee3
      由 Brian Foster 提交于 
      The inode btree verifier code is shared between the inode btree and
free inode btree because the underlying metadata formats are
essentially equivalent. A side effect of this is that the verifier
cannot determine whether a particular btree block should have an
inobt or finobt magic value.

This logic allows an unfortunate xfs_repair bug to escape detection
where certain level > 0 nodes of the finobt are stamped with inobt
magic by xfs_repair finobt reconstruction. This is fortunately not a
severe problem since the inode btree magic values do not contribute
to any changes in kernel behavior, but we do need a means to detect
and prevent this problem in the future.

Add a field to xfs_buf_ops to store the v4 and v5 superblock magic
values expected by a particular verifier. Add a helper to check an
on-disk magic value against the value expected by the verifier. Call
the helper from the shared [f]inobt verifier code for magic value
verification. This ensures that the inode btree blocks each have the
appropriate magic value based on specific tree type and superblock
version.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
      8473fee3
    • B
      xfs: clarify documentation for the function to reverify buffers · 75d02303
      由 Brian Foster 提交于 
      Improve the documentation around xfs_buf_ensure_ops, which is the
function that is responsible for cleaning up the b_ops state of buffers
that go through xrep_findroot_block but don't match anything.  Rename
the function to xfs_buf_reverify.

[darrick: this started off as bfoster mods of a previous patch of mine,
but the renaming part is now this separate patch.]
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NBrian Foster <bfoster@redhat.com>
      75d02303
  33. 04 2月, 2019 2 次提交
    • D
      xfs: set buffer ops when repair probes for btree type · add46b3b
      由 Darrick J. Wong 提交于 
      In xrep_findroot_block, we work out the btree type and correctness of a
given block by calling different btree verifiers on root block
candidates.  However, we leave the NULL b_ops while ->verify_read
validates the block, which means that if the verifier calls
xfs_buf_verifier_error it'll crash on the null b_ops.  Fix it to set
b_ops before calling the verifier and unsetting it if the verifier
fails.

Furthermore, improve the documentation around xfs_buf_ensure_ops, which
is the function that is responsible for cleaning up the b_ops state of
buffers that go through xrep_findroot_block but don't match anything.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
      add46b3b
    • B
      xfs: end sync buffer I/O properly on shutdown error · 465fa17f
      由 Brian Foster 提交于 
      As of commit e339dd8d ("xfs: use sync buffer I/O for sync delwri
queue submission"), the delwri submission code uses sync buffer I/O
for sync delwri I/O. Instead of waiting on async I/O to unlock the
buffer, it uses the underlying sync I/O completion mechanism.

If delwri buffer submission fails due to a shutdown scenario, an
error is set on the buffer and buffer completion never occurs. This
can cause xfs_buf_delwri_submit() to deadlock waiting on a
completion event.

We could check the error state before waiting on such buffers, but
that doesn't serialize against the case of an error set via a racing
I/O completion. Instead, invoke I/O completion in the shutdown case
regardless of buffer I/O type.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
      465fa17f
  35. 30 12月, 2018 1 次提交
  37. 18 10月, 2018 3 次提交
    • B
      xfs: clear ail delwri queued bufs on unmount of shutdown fs · efc3289c
      由 Brian Foster 提交于 
      In the typical unmount case, the AIL is forced out by the unmount
sequence before the xfsaild task is stopped. Since AIL items are
removed on writeback completion, this means that the AIL
->ail_buf_list delwri queue has been drained. This is not always
true in the shutdown case, however.

It's possible for buffers to sit on a delwri queue for a period of
time across submission attempts if said items are locked or have
been relogged and pinned since first added to the queue. If the
attempt to log such an item results in a log I/O error, the error
processing can shutdown the fs, remove the item from the AIL, stale
the buffer (dropping the LRU reference) and clear its delwri queue
state. The latter bit means the buffer will be released from a
delwri queue on the next submission attempt, but this might never
occur if the filesystem has shutdown and the AIL is empty.

This means that such buffers are held indefinitely by the AIL delwri
queue across destruction of the AIL. Aside from being a memory leak,
these buffers can also hold references to in-core perag structures.
The latter problem manifests as a generic/475 failure, reproducing
the following asserts at unmount time:

  XFS: Assertion failed: atomic_read(&pag->pag_ref) == 0,
	file: fs/xfs/xfs_mount.c, line: 151
  XFS: Assertion failed: atomic_read(&pag->pag_ref) == 0,
	file: fs/xfs/xfs_mount.c, line: 132

To prevent this problem, clear the AIL delwri queue as a final step
before xfsaild() exit. The !empty state should never occur in the
normal case, so add an assert to catch unexpected problems going
forward.

[dgc: add comment explaining need for xfs_buf_delwri_cancel() after
 calling xfs_buf_delwri_submit_nowait().]
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>
      efc3289c
    • D
      xfs: fix use-after-free race in xfs_buf_rele · 37fd1678
      由 Dave Chinner 提交于 
      When looking at a 4.18 based KASAN use after free report, I noticed
that racing xfs_buf_rele() may race on dropping the last reference
to the buffer and taking the buffer lock. This was the symptom
displayed by the KASAN report, but the actual issue that was
reported had already been fixed in 4.19-rc1 by commit e339dd8d
("xfs: use sync buffer I/O for sync delwri queue submission").

Despite this, I think there is still an issue with xfs_buf_rele()
in this code:

        release = atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock);
        spin_lock(&bp->b_lock);
        if (!release) {
.....

If two threads race on the b_lock after both dropping a reference
and one getting dropping the last reference so release = true, we
end up with:

CPU 0				CPU 1
atomic_dec_and_lock()
				atomic_dec_and_lock()
				spin_lock(&bp->b_lock)
spin_lock(&bp->b_lock)
<spins>
				<release = true bp->b_lru_ref = 0>
				<remove from lists>
				freebuf = true
				spin_unlock(&bp->b_lock)
				xfs_buf_free(bp)
<gets lock, reading and writing freed memory>
<accesses freed memory>
spin_unlock(&bp->b_lock) <reads/writes freed memory>

IOWs, we can't safely take bp->b_lock after dropping the hold
reference because the buffer may go away at any time after we
drop that reference. However, this can be fixed simply by taking the
bp->b_lock before we drop the reference.

It is safe to nest the pag_buf_lock inside bp->b_lock as the
pag_buf_lock is only used to serialise against lookup in
xfs_buf_find() and no other locks are held over or under the
pag_buf_lock there. Make this clear by documenting the buffer lock
orders at the top of the file.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com
Signed-off-by: NDave Chinner <david@fromorbit.com>
      37fd1678
    • D
      xfs: always assign buffer verifiers when one is provided · 1aff5696
      由 Darrick J. Wong 提交于 
      If a caller supplies buffer ops when trying to read a buffer and the
buffer doesn't already have buf ops assigned, ensure that the ops are
assigned to the buffer and the verifier is run on that buffer.

Note that current XFS code is careful to assign buffer ops after a
xfs_{trans_,}buf_read call in which ops were not supplied.  However, we
should apply ops defensively in case there is ever a coding mistake; and
an upcoming repair patch will need to be able to read a buffer without
assigning buf ops.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Chinner <david@fromorbit.com>
      1aff5696
  39. 12 8月, 2018 1 次提交
  41. 12 7月, 2018 2 次提交