Commit Graph

218 Commits

Author SHA1 Message Date
Dave Chinner 12eba65b28 xfs: Improve metadata buffer reclaim accountability
The buffer cache shrinker frees more than just the xfs_buf slab
objects - it also frees the pages attached to the buffers. Make sure
the memory reclaim code accounts for this memory being freed
correctly, similar to how the inode shrinker accounts for pages
freed from the page cache due to mapping invalidation.

We also need to make sure that the mm subsystem knows these are
reclaimable objects. We provide the memory reclaim subsystem with a
a shrinker to reclaim xfs_bufs, so we should really mark the slab
that way.

We also have a lot of xfs_bufs in a busy system, spread them around
like we do inodes.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-03-27 08:32:54 -07:00
Darrick J. Wong e83cf875d6 xfs: xfs_buf_corruption_error should take __this_address
Add a xfs_failaddr_t parameter to this function so that callers can
potentially pass in (and therefore report) the exact point in the code
where we decided that a metadata buffer was corrupt.  This enables us to
wire it up to checking functions that have to run outside of verifiers.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-03-12 07:58:12 -07:00
Darrick J. Wong 8d57c21600 xfs: add a function to deal with corrupt buffers post-verifiers
Add a helper function to get rid of buffers that we have decided are
corrupt after the verifiers have run.  This function is intended to
handle metadata checks that can't happen in the verifiers, such as
inter-block relationship checking.  Note that we now mark the buffer
stale so that it will not end up on any LRU and will be purged on
release.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-03-12 07:58:12 -07:00
Christoph Hellwig 13b1f811b1 xfs: ratelimit xfs_buf_ioerror_alert messages
Use printk_ratelimit() to limit the amount of messages printed from
xfs_buf_ioerror_alert.  Without that a failing device causes a large
number of errors that doesn't really help debugging the underling
issue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-03-02 20:55:51 -08:00
Darrick J. Wong 93baa55af1 xfs: improve error message when we can't allocate memory for xfs_buf
If xfs_buf_get_map can't allocate enough memory for the buffer it's
trying to create, it'll cough up an error about not being able to
allocate "pagesn".  That's not particularly helpful (and if we're really
out of memory the message is very spammy) so change the message to tell
us how many pages were actually requested, and ratelimit it too.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-03-02 20:55:50 -08:00
Darrick J. Wong cdbcf82b86 xfs: fix xfs_buf_ioerror_alert location reporting
Instead of passing __func__ to the error reporting function, let's use
the return address builtins so that the messages actually tell you which
higher level function called the buffer functions.  This was previously
true for the xfs_buf_read callers, but not for the xfs_trans_read_buf
callers.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-01-26 14:32:27 -08:00
Darrick J. Wong 2842b6db3d xfs: make xfs_buf_get_uncached return an error code
Convert xfs_buf_get_uncached() to return numeric error codes like most
everywhere else in xfs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-01-26 14:32:26 -08:00
Darrick J. Wong 4ed8e27b4f xfs: make xfs_buf_read_map return an error code
Convert xfs_buf_read_map() to return numeric error codes like most
everywhere else in xfs.  This involves moving the open-coded logic that
reports metadata IO read / corruption errors and stales the buffer into
xfs_buf_read_map so that the logic is all in one place.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-01-26 14:32:26 -08:00
Darrick J. Wong 3848b5f670 xfs: make xfs_buf_get_map return an error code
Convert xfs_buf_get_map() to return numeric error codes like most
everywhere else in xfs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-01-26 14:32:25 -08:00
Darrick J. Wong 32dff5e5d1 xfs: make xfs_buf_alloc return an error code
Convert _xfs_buf_alloc() to return numeric error codes like most
everywhere else in xfs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-01-26 14:32:25 -08:00
Carlos Maiolino 377bcd5f3b xfs: Remove kmem_zone_free() wrapper
We can remove it now, without needing to rework the KM_ flags.

Use kmem_cache_free() directly.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-11-18 08:40:44 -08:00
Carlos Maiolino aaf54eb8bc xfs: Remove kmem_zone_destroy() wrapper
Use kmem_cache_destroy directly

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-11-18 08:40:44 -08:00
Carlos Maiolino b1231760e4 xfs: Remove slab init wrappers
Remove kmem_zone_init() and kmem_zone_init_flags() together with their
specific KM_* to SLAB_* flag wrappers.

Use kmem_cache_create() directly.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-11-18 08:40:43 -08:00
Joe Perches cf085a1b5d xfs: Correct comment tyops -> typos
Just fix the typos checkpatch notices...

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-11-10 10:21:57 -08:00
Christoph Hellwig 2123ef8510 xfs: simplify setting bio flags
Stop using the deprecated bio_set_op_attrs helper, and use a single
argument to xfs_buf_ioapply_map for the operation and flags.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-10-29 09:50:12 -07:00
Christoph Hellwig 25a409572b xfs: mark xfs_buf_free static
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-10-28 08:37:54 -07:00
Bill O'Donnell 3219e8cf0d xfs: assure zeroed memory buffers for certain kmem allocations
Guarantee zeroed memory buffers for cases where potential memory
leak to disk can occur. In these cases, kmem_alloc is used and
doesn't zero the buffer, opening the possibility of information
leakage to disk.

Use existing infrastucture (xfs_buf_allocate_memory) to obtain
the already zeroed buffer from kernel memory.

This solution avoids the performance issue that would occur if a
wholesale change to replace kmem_alloc with kmem_zalloc was done.

Signed-off-by: Bill O'Donnell <billodo@redhat.com>
[darrick: fix bitwise complaint about kmflag_mask]
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-10-06 15:39:06 -07:00
Denis Efremov 14ed868807 xfs: remove unlikely() from WARN_ON() condition
"unlikely(WARN_ON(x))" is excessive. WARN_ON() already uses unlikely()
internally.

Link: http://lkml.kernel.org/r/20190829165025.15750-7-efremov@linux.com
Signed-off-by: Denis Efremov <efremov@linux.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-26 10:10:30 -07:00
Dave Chinner f8f9ee4794 xfs: add kmem_alloc_io()
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: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-08-26 17:43:15 -07:00
Tetsuo Handa 707e0ddaf6 fs: xfs: Remove KM_NOSLEEP and KM_SLEEP.
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: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-08-26 12:06:22 -07:00
Eric Sandeen 250d4b4c40 xfs: remove unused header files
There are many, many xfs header files which are included but
unneeded (or included twice) in the xfs code, so remove them.

nb: xfs_linux.h includes about 9 headers for everyone, so those
explicit includes get removed by this.  I'm not sure what the
preference is, but if we wanted explicit includes everywhere,
a followup patch could remove those xfs_*.h includes from
xfs_linux.h and move them into the files that need them.
Or it could be left as-is.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-28 19:30:43 -07:00
Christoph Hellwig dbd329f1e4 xfs: add struct xfs_mount pointer to struct xfs_buf
We need to derive the mount pointer from a buffer in a lot of place.
Add a direct pointer to short cut the pointer chasing.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-28 19:27:29 -07:00
Christoph Hellwig 8124b9b601 xfs: remove the b_io_length field in struct xfs_buf
This field is now always idential to b_length.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-28 19:27:28 -07:00
Christoph Hellwig 0564501ff5 xfs: remove unused buffer cache APIs
Now that the log code uses bios directly we can drop various special
cases in the buffer cache code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-28 19:27:27 -07:00
Christoph Hellwig 72945d86dd xfs: make mem_to_page available outside of xfs_buf.c
Rename the function to kmem_to_page and move it to kmem.h together
with our kmem_large allocator that may either return kmalloced or
vmalloc pages.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-28 19:27:19 -07:00
Darrick J. Wong 5467b34bd1 xfs: move xfs_ino_geometry to xfs_shared.h
The inode geometry structure isn't related to ondisk format; it's
support for the mount structure.  Move it to xfs_shared.h.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2019-06-28 19:25:35 -07:00
Christoph Hellwig f9a196ee5a xfs: merge xfs_buf_zero and xfs_buf_iomove
xfs_buf_zero is the only caller of xfs_buf_iomove.  Remove support
for copying from or to the buffer in xfs_buf_iomove and merge the
two functions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-12 08:59:59 -07:00
Darrick J. Wong 15baadf72c xfs: fix xfs_buf magic number endian checks
Create a separate magic16 check function so that we don't run afoul of
static checkers.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2019-02-18 09:38:41 -08:00
Brian Foster 8473fee340 xfs: distinguish between inobt and finobt magic values
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: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-02-11 16:07:01 -08:00
Brian Foster 75d0230314 xfs: clarify documentation for the function to reverify buffers
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: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Brian Foster <bfoster@redhat.com>
2019-02-11 16:07:01 -08:00
Darrick J. Wong add46b3b02 xfs: set buffer ops when repair probes for btree type
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: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2019-02-03 14:03:59 -08:00
Brian Foster 465fa17f4a xfs: end sync buffer I/O properly on shutdown error
As of commit e339dd8d8b ("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: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-02-03 14:03:06 -08:00
Julia Lawall 89be677b6b xfs: xfs_buf: drop useless LIST_HEAD
Drop LIST_HEAD where the variable it declares has never
been used.

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier x;
@@
- LIST_HEAD(x);
  ... when != x
// </smpl>

Fixes: 26f1fe858f ("xfs: reduce lock hold times in buffer writeback")
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-12-29 10:47:34 -08:00
Brian Foster efc3289cf8 xfs: clear ail delwri queued bufs on unmount of shutdown fs
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: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-18 17:21:49 +11:00
Dave Chinner 37fd167824 xfs: fix use-after-free race in xfs_buf_rele
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 e339dd8d8b
("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: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com
Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-18 17:21:29 +11:00
Darrick J. Wong 1aff5696f3 xfs: always assign buffer verifiers when one is provided
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: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-18 17:20:30 +11:00
Eric Sandeen fa6c668d80 xfs: remove b_last_holder & associated macros
The old lock tracking infrastructure in xfs using the b_last_holder
field seems to only be useful if you can get into the system with a
debugger; it seems that the existing tracepoints would be the way to
go these days, and this old infrastructure can be removed.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-08-12 08:37:31 -07:00
Brian Foster bb00b6f1e2 xfs: kill __xfs_buf_submit_common()
Now that there is only one caller, fold the common submission helper
into __xfs_buf_submit().

Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-11 22:26:35 -07:00
Brian Foster 6af88cda00 xfs: combine [a]sync buffer submission apis
The buffer I/O submission path consists of separate function calls
per type. The buffer I/O type is already controlled via buffer
state (XBF_ASYNC), however, so there is no real need for separate
submission functions.

Combine the buffer submission functions into a single function that
processes the buffer appropriately based on XBF_ASYNC. Retain an
internal helper with a conditional wait parameter to continue to
support batched !XBF_ASYNC submission/completion required by delwri
queues.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-11 22:26:35 -07:00
Brian Foster e339dd8d8b xfs: use sync buffer I/O for sync delwri queue submission
If a delwri queue occurs of a buffer that sits on a delwri queue
wait list, the queue sets _XBF_DELWRI_Q without changing the state
of ->b_list. This occurs, for example, if another thread beats the
current delwri waiter thread to the buffer lock after I/O
completion. Once the waiter acquires the lock, it removes the buffer
from the wait list and leaves a buffer with _XBF_DELWRI_Q set but
not populated on a list. This results in a lost buffer submission
and in turn can result in assert failures due to _XBF_DELWRI_Q being
set on buffer reclaim or filesystem lockups if the buffer happens to
cover an item in the AIL.

This problem has been reproduced by repeated iterations of xfs/305
on high CPU count (28xcpu) systems with limited memory (~1GB). Dirty
dquot reclaim races with an xfsaild push of a separate dquot backed
by the same buffer such that the buffer sits on the reclaim wait
list at the time xfsaild attempts to queue it. Since the latter
dquot has been flush locked but the underlying buffer not submitted
for I/O, the dquot pins the AIL and causes the filesystem to
livelock.

This race is essentially made possible by the buffer lock cycle
involved with waiting on a synchronous delwri queue submission.
Close the race by using synchronous buffer I/O for respective delwri
queue submission. This means the buffer remains locked across the
I/O and so is inaccessible from other contexts while in the
intermediate wait list state. The sync buffer I/O wait mechanism is
factored into a helper such that sync delwri buffer submission and
serialization are batched operations.

Designed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-11 22:26:34 -07:00
Brian Foster eaebb515f1 xfs: refactor buffer submission into a common helper
Sync and async buffer submission both do generally similar things
with a couple odd exceptions. Refactor the core buffer submission
code into a common helper to isolate buffer submission from
completion handling of synchronous buffer I/O.

This patch does not change behavior. It is a step towards support
for using synchronous buffer I/O via synchronous delwri queue
submission.

Designed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-11 22:26:34 -07:00
Dave Chinner 4a2d01b076 xfs: xfs_reflink_convert_cow() memory allocation deadlock
xfs_reflink_convert_cow() manipulates the incore extent list
in GFP_KERNEL context in the IO submission path whilst holding
locked pages under writeback. This is a memory reclaim deadlock
vector. This code is not in a transaction, so any memory allocations
it makes aren't protected via the memalloc_nofs_save() context that
transactions carry.

Hence we need to run this call under memalloc_nofs_save() context to
prevent potential memory allocations from being run as GFP_KERNEL
and deadlocking.

Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-06-08 10:07:51 -07:00
Dave Chinner 0b61f8a407 xfs: convert to SPDX license tags
Remove the verbose license text from XFS files and replace them
with SPDX tags. This does not change the license of any of the code,
merely refers to the common, up-to-date license files in LICENSES/

This change was mostly scripted. fs/xfs/Makefile and
fs/xfs/libxfs/xfs_fs.h were modified by hand, the rest were detected
and modified by the following command:

for f in `git grep -l "GNU General" fs/xfs/` ; do
	echo $f
	cat $f | awk -f hdr.awk > $f.new
	mv -f $f.new $f
done

And the hdr.awk script that did the modification (including
detecting the difference between GPL-2.0 and GPL-2.0+ licenses)
is as follows:

$ cat hdr.awk
BEGIN {
	hdr = 1.0
	tag = "GPL-2.0"
	str = ""
}

/^ \* This program is free software/ {
	hdr = 2.0;
	next
}

/any later version./ {
	tag = "GPL-2.0+"
	next
}

/^ \*\// {
	if (hdr > 0.0) {
		print "// SPDX-License-Identifier: " tag
		print str
		print $0
		str=""
		hdr = 0.0
		next
	}
	print $0
	next
}

/^ \* / {
	if (hdr > 1.0)
		next
	if (hdr > 0.0) {
		if (str != "")
			str = str "\n"
		str = str $0
		next
	}
	print $0
	next
}

/^ \*/ {
	if (hdr > 0.0)
		next
	print $0
	next
}

// {
	if (hdr > 0.0) {
		if (str != "")
			str = str "\n"
		str = str $0
		next
	}
	print $0
}

END { }
$

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-06-06 14:17:53 -07:00
Dave Chinner b027d4c97b xfs: don't retry xfs_buf_find on XBF_TRYLOCK failure
When looking at an event trace recently, I noticed that non-blocking
buffer lookup attempts would fail on cached locked buffers and then
run the slow cache-miss path. This means we are doing an xfs_buf
allocation, lookup and free unnecessarily every time we avoid
blocking on a locked buffer.

Fix this by changing _xfs_buf_find() to return an error status to
the caller to indicate that we failed the lock attempt rather than
just returning a NULL. This allows the higher level code to
discriminate between a cache miss and an cache hit that we failed to
lock.

This also allows us to return a -EFSCORRUPTED state if we are asked
to look up a block number outside the range of the filesystem in
_xfs_buf_find(), which moves us one step closer to being able to
handle such errors in a more graceful manner at the higher levels.

Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-05-09 10:04:00 -07:00
Dave Chinner 8925a3dc47 xfs: make xfs_buf_incore out of line
Move xfs_buf_incore out of line and make it the only way to look up
a buffer in the buffer cache from outside the buffer cache. Convert
the external users of _xfs_buf_find() to xfs_buf_incore() and make
_xfs_buf_find() static.

Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: actually rename xfs_incore -> xfs_buf_incore]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-05-09 10:04:00 -07:00
Eric Sandeen a1f69417c6 xfs: non-scrub - remove unused function parameters
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-04-09 10:23:42 -07:00
Vratislav Bendel 19957a1816 xfs: Correctly invert xfs_buftarg LRU isolation logic
Due to an inverted logic mistake in xfs_buftarg_isolate()
the xfs_buffers with zero b_lru_ref will take another trip
around LRU, while isolating buffers with non-zero b_lru_ref.

Additionally those isolated buffers end up right back on the LRU
once they are released, because b_lru_ref remains elevated.

Fix that circuitous route by leaving them on the LRU
as originally intended.

Signed-off-by: Vratislav Bendel <vbendel@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-03-11 20:27:56 -07:00
Carlos Maiolino 643c8c05e7 Use list_head infra-structure for buffer's log items list
Now that buffer's b_fspriv has been split, just replace the current
singly linked list of xfs_log_items, by the list_head infrastructure.

Also, remove the xfs_log_item argument from xfs_buf_resubmit_failed_buffers(),
there is no need for this argument, once the log items can be walked
through the list_head in the buffer.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: minor style cleanups]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-01-29 07:27:22 -08:00
Darrick J. Wong c219b01579 xfs: clarify units in the failed metadata io message
If a metadata IO error happens, we report the location of the failed IO
request in units of daddrs.  However, the printk message misleads people
into thinking that the units are fs blocks, so fix the reported units.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2018-01-09 15:18:07 -08:00
Darrick J. Wong 9c712a1346 xfs: dump the first 128 bytes of any corrupt buffer
Increase the corrupt buffer dump to the first 128 bytes since v5
filesystems have larger block headers than before.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2018-01-08 10:54:47 -08:00