Christoph Hellwig complained about the following soft lockup warning
when running scrub after generic/175 when preemption is disabled and
slub debugging is enabled:
watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [xfs_scrub:161]
Modules linked in:
irq event stamp: 41692326
hardirqs last enabled at (41692325): [<ffffffff8232c3b7>] _raw_0
hardirqs last disabled at (41692326): [<ffffffff81001c5a>] trace0
softirqs last enabled at (41684994): [<ffffffff8260031f>] __do_e
softirqs last disabled at (41684987): [<ffffffff81127d8c>] irq_e0
CPU: 3 PID: 16189 Comm: xfs_scrub Not tainted 5.4.0-rc3+ #30
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.124
RIP: 0010:_raw_spin_unlock_irqrestore+0x39/0x40
Code: 89 f3 be 01 00 00 00 e8 d5 3a e5 fe 48 89 ef e8 ed 87 e5 f2
RSP: 0018:ffffc9000233f970 EFLAGS: 00000286 ORIG_RAX: ffffffffff3
RAX: ffff88813b398040 RBX: 0000000000000286 RCX: 0000000000000006
RDX: 0000000000000006 RSI: ffff88813b3988c0 RDI: ffff88813b398040
RBP: ffff888137958640 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffea00042b0c00
R13: 0000000000000001 R14: ffff88810ac32308 R15: ffff8881376fc040
FS: 00007f6113dea700(0000) GS:ffff88813bb80000(0000) knlGS:00000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6113de8ff8 CR3: 000000012f290000 CR4: 00000000000006e0
Call Trace:
free_debug_processing+0x1dd/0x240
__slab_free+0x231/0x410
kmem_cache_free+0x30e/0x360
xchk_ag_btcur_free+0x76/0xb0
xchk_ag_free+0x10/0x80
xchk_bmap_iextent_xref.isra.14+0xd9/0x120
xchk_bmap_iextent+0x187/0x210
xchk_bmap+0x2e0/0x3b0
xfs_scrub_metadata+0x2e7/0x500
xfs_ioc_scrub_metadata+0x4a/0xa0
xfs_file_ioctl+0x58a/0xcd0
do_vfs_ioctl+0xa0/0x6f0
ksys_ioctl+0x5b/0x90
__x64_sys_ioctl+0x11/0x20
do_syscall_64+0x4b/0x1a0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
If preemption is disabled, all metadata buffers needed to perform the
scrub are already in memory, and there are a lot of records to check,
it's possible that the scrub thread will run for an extended period of
time without sleeping for IO or any other reason. Then the watchdog
timer or the RCU stall timeout can trigger, producing the backtrace
above.
To fix this problem, call cond_resched() from the scrub thread so that
we back out to the scheduler whenever necessary.
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Teach online scrub how to check the filesystem summary counters. We use
the incore delalloc block counter along with the incore AG headers to
compute expected values for fdblocks, icount, and ifree, and then check
that the percpu counter is within a certain threshold of the expected
value. This is done to avoid having to freeze or otherwise lock the
filesystem, which means that we're only checking that the counters are
fairly close, not that they're exactly correct.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
The forthcoming summary counter patch races with regular filesystem
activity to compute rough expected values for the counters. This design
was chosen to avoid having to freeze the entire filesystem to check the
counters, but while that's running we'd prefer to minimize background
reclamation activity to reduce the perturbations to the incore free
block count. Therefore, provide a way for scrubbers to disable
background posteof and cowblock reclamation.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Only certain functions actually change the contents of an
xfs_owner_info; the rest can accept a const struct pointer. This will
enable us to save stack space by hoisting static owner info types to
be const global variables.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Now that we've shortened everything, fix up all the indentation and
whitespace problems. There are no functional changes.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Shorten the name of the online fsck context structure. Whitespace
damage will be fixed by a subsequent patch. There are no functional
changes.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Shorten all the metadata checking xfs_scrub_ prefixes to xchk_. After
this, the only xfs_scrub* symbols are the ones that pertain to both
scrub and repair. Whitespace damage will be fixed in a subsequent
patch. There are no functional changes.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
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>
For repairs, we need to reserve at least as many blocks as we think
we're going to need to rebuild the data structure, and we're going to
need some helpers to roll transactions while maintaining locks on the AG
headers so that other threads cannot wander into the middle of a repair.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Grab and hold the per-AG data across a scrub run whenever relevant.
This helps us avoid repeated trips through rcu and the radix tree
in the repair code.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
This function is basically a generic AGFL block iterator, so promote it
to libxfs ahead of online repair wanting to use it.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
In normal operation, the XFS convention is to take an inode's iolock
and then allocate a transaction. However, when scrubbing parent inodes
this is inverted -- we allocated the transaction to do the scrub, and
now we're trying to grab the parent's iolock. This can lead to ABBA
deadlocks: some thread grabbed the parent's iolock and is waiting for
space for a transaction while our parent scrubber is sitting on a
transaction trying to get the parent's iolock.
Therefore, convert all iolock attempts to use trylock; if that fails,
they can use the existing mechanisms to back off and try again.
The ABBA deadlock didn't happen with a non-repair scrub because the
transactions don't reserve any space, but repair scrubs require
reservation in order to update metadata. However, any other concurrent
metadata update (e.g. directory create in the parent) could also induce
this deadlock with the parent scrubber.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Replace the quota scrubber's open-coded data fork scrubber with a
redirected call to the bmapbtd scrubber. This strengthens the quota
scrub to include all the cross-referencing that it does.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Don't bother looking for cross-referencing problems if the metadata is
already corrupt or we've already found a cross-referencing problem.
Since we added a helper function for flags testing, convert existing
users to use it.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Since the transaction allocation helper is about to become more complex,
move it to common.c and remove the redundant parameters.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Now that we no longer do raw inode buffer scrubbing, the bp parameter is
no longer used anywhere we're dealing with an inode, so remove it and
all the useless NULL parameters that go with it.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Whenever we load a buffer, explicitly re-call the structure verifier to
ensure that memory isn't corrupting things.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
When scrubbing various btrees, we should cross-reference the records
with the reverse mapping btree and ensure that traversing the btree
finds the same number of blocks that the rmapbt thinks are owned by
that btree.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Create some helper functions that we'll use later to deal with problems
we might encounter while cross referencing metadata with other metadata.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
There were ad-hoc checks for some scrub types but not others;
mark each scrub type with ... it's type, and use that to validate
the allowed and/or required input fields.
Moving these checks out of xfs_scrub_setup_ag_header makes it
a thin wrapper, so unwrap it in the process.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
[darrick: add xfs_ prefix to enum, check scrub args after checking type]
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
There are two ways to scrub an inode -- calling xfs_iget and checking
the raw inode core, or by loading the inode cluster buffer and checking
the on-disk contents directly. The second method is only useful if
_iget fails the verifiers; when this is the case, sc->ip is NULL and
calling the tracepoint will cause a system crash.
Therefore, pass the raw inode number directly into the _preen and
_warning functions.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Perform some quick sanity testing of the disk quota information.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Perform simple tests of the realtime bitmap and summary.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Scrub parent pointers, sort of. For directories, we can ride the
'..' entry up to the parent to confirm that there's at most one
dentry that points back to this directory.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Create the infrastructure to scrub symbolic link data.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Scrub the hash tree, keys, and values in an extended attribute structure.
Refactor the attribute code to use the transaction if the caller supplied
one to avoid buffer deadocks.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Scrub the hash tree and all the entries in a directory.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Scrub an individual inode's block mappings to make sure they make sense.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Plumb in the pieces necessary to check the refcount btree. If rmap is
available, check the reference count by performing an interval query
against the rmapbt.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Check the reverse mapping records to make sure that the contents
make sense.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Check the records of the inode btrees to make sure that the values
make sense given the inode records themselves.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Check the extent records free space btrees to ensure that the values
look sane.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Check the block references in the AGF and AGFL headers to make sure
they make sense.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Ensure that the geometry presented in the backup superblocks matches
the primary superblock so that repair can recover the filesystem if
that primary gets corrupted.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Add some helpers to enable us to lock an AG's headers, create btree
cursors for all btrees in that allocation group, and clean up
afterwards.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Create helper functions to record crc and corruption problems, and
deal with any other runtime errors that arise.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Create a probe scrubber with id 0. This will be used by xfs_scrub to
probe the kernel's abilities to scrub (and repair) the metadata. We do
this by validating the ioctl inputs from userspace, preparing the
filesystem for a scrub (or a repair) operation, and immediately
returning to userspace. Userspace can use the returned errno and
structure state to decide (in broad terms) if scrub/repair are
supported by the running kernel.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Darrick J. Wong