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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Since all verification errors also mark the buffer as having an error,
we can combine these two calls. Later we'll add a xfs_failaddr_t
parameter to promote the idea of reporting corruption errors and the
address of the failing check to enable better debugging reports.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
percpu_counter_init failure path doesn't clean up &btp->bt_lru list.
Call list_lru_destroy in that error path. Similarly register_shrinker
error path is not handled.
While it is unlikely to trigger these error path, it is not impossible
especially the later might fail with large NUMAs. Let's handle the
failure to make the code more robust.
Noticed-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-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>
Move the error injection tag names into a libxfs header so that we can
share it between kernel and userspace.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Fix an unused variable warning on non-DEBUG builds introduced by
commit 7561d27e90 ("xfs: buffer lru reference count error injection
tag").
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>
XFS uses a fixed reference count for certain types of buffers in the
internal LRU cache. These reference counts dictate how aggressively
certain buffers are reclaimed vs. others. While the reference counts
implements priority across different buffer types, all buffers
(other than uncached buffers) are typically cached for at least one
reclaim cycle.
We've had at least one bug recently that has been hidden by a
released buffer sitting around in the LRU. Users hitting the problem
were able to reproduce under enough memory pressure to cause
aggressive reclaim in a particular window of time.
To support future xfstests cases, add an error injection tag to
hardcode the buffer reference count to zero. When enabled, this
bypasses caching of associated buffers and facilitates test cases
that depend on this behavior.
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>
Variable total_nr_pages is being initialized and then updated with
the same value, this latter assignment is redundant and can be
removed. Cleans up clang build warning:
Value stored to 'total_nr_pages' during its initialization is never read
Signed-off-by: Colin Ian King <colin.king@canonical.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>
* Media error handling support in the Block Translation Table (BTT)
driver is reworked to address sleeping-while-atomic locking and
memory-allocation-context conflicts.
* The dax_device lookup overhead for xfs and ext4 is moved out of the
iomap hot-path to a mount-time lookup.
* A new 'ecc_unit_size' sysfs attribute is added to advertise the
read-modify-write boundary property of a persistent memory range.
* Preparatory fix-ups for arm and powerpc pmem support are included
along with other miscellaneous fixes.
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Merge tag 'libnvdimm-for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm from Dan Williams:
"A rework of media error handling in the BTT driver and other updates.
It has appeared in a few -next releases and collected some late-
breaking build-error and warning fixups as a result.
Summary:
- Media error handling support in the Block Translation Table (BTT)
driver is reworked to address sleeping-while-atomic locking and
memory-allocation-context conflicts.
- The dax_device lookup overhead for xfs and ext4 is moved out of the
iomap hot-path to a mount-time lookup.
- A new 'ecc_unit_size' sysfs attribute is added to advertise the
read-modify-write boundary property of a persistent memory range.
- Preparatory fix-ups for arm and powerpc pmem support are included
along with other miscellaneous fixes"
* tag 'libnvdimm-for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (26 commits)
libnvdimm, btt: fix format string warnings
libnvdimm, btt: clean up warning and error messages
ext4: fix null pointer dereference on sbi
libnvdimm, nfit: move the check on nd_reserved2 to the endpoint
dax: fix FS_DAX=n BLOCK=y compilation
libnvdimm: fix integer overflow static analysis warning
libnvdimm, nd_blk: remove mmio_flush_range()
libnvdimm, btt: rework error clearing
libnvdimm: fix potential deadlock while clearing errors
libnvdimm, btt: cache sector_size in arena_info
libnvdimm, btt: ensure that flags were also unchanged during a map_read
libnvdimm, btt: refactor map entry operations with macros
libnvdimm, btt: fix a missed NVDIMM_IO_ATOMIC case in the write path
libnvdimm, nfit: export an 'ecc_unit_size' sysfs attribute
ext4: perform dax_device lookup at mount
ext2: perform dax_device lookup at mount
xfs: perform dax_device lookup at mount
dax: introduce a fs_dax_get_by_bdev() helper
libnvdimm, btt: check memory allocation failure
libnvdimm, label: fix index block size calculation
...
The ->iomap_begin() operation is a hot path, so cache the
fs_dax_get_by_host() result at mount time to avoid the incurring the
hash lookup overhead on a per-i/o basis.
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This way we don't need a block_device structure to submit I/O. The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open. Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).
For the actual I/O path all that we need is the gendisk, which exists
once per block device. But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.
Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
- Avoid quotacheck deadlocks
- Fix transaction overflows when bunmapping fragmented files
- Refactor directory readahead
- Allow admin to configure if ASSERT is fatal
- Improve transaction usage detail logging during overflows
- Minor cleanups
- Don't leak log items when the log shuts down
- Remove double-underscore typedefs
- Various preparation for online scrubbing
- Introduce new error injection configuration sysfs knobs
- Refactor dq_get_next to use extent map directly
- Fix problems with iterating the page cache for unwritten data
- Implement SEEK_{HOLE,DATA} via iomap
- Refactor XFS to use iomap SEEK_HOLE and SEEK_DATA
- Don't use MAXPATHLEN to check on-disk symlink target lengths
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Merge tag 'xfs-4.13-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull XFS updates from Darrick Wong:
"Here are some changes for you for 4.13. For the most part it's fixes
for bugs and deadlock problems, and preparation for online fsck in
some future merge window.
- Avoid quotacheck deadlocks
- Fix transaction overflows when bunmapping fragmented files
- Refactor directory readahead
- Allow admin to configure if ASSERT is fatal
- Improve transaction usage detail logging during overflows
- Minor cleanups
- Don't leak log items when the log shuts down
- Remove double-underscore typedefs
- Various preparation for online scrubbing
- Introduce new error injection configuration sysfs knobs
- Refactor dq_get_next to use extent map directly
- Fix problems with iterating the page cache for unwritten data
- Implement SEEK_{HOLE,DATA} via iomap
- Refactor XFS to use iomap SEEK_HOLE and SEEK_DATA
- Don't use MAXPATHLEN to check on-disk symlink target lengths"
* tag 'xfs-4.13-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (48 commits)
xfs: don't crash on unexpected holes in dir/attr btrees
xfs: rename MAXPATHLEN to XFS_SYMLINK_MAXLEN
xfs: fix contiguous dquot chunk iteration livelock
xfs: Switch to iomap for SEEK_HOLE / SEEK_DATA
vfs: Add iomap_seek_hole and iomap_seek_data helpers
vfs: Add page_cache_seek_hole_data helper
xfs: remove a whitespace-only line from xfs_fs_get_nextdqblk
xfs: rewrite xfs_dq_get_next_id using xfs_iext_lookup_extent
xfs: Check for m_errortag initialization in xfs_errortag_test
xfs: grab dquots without taking the ilock
xfs: fix semicolon.cocci warnings
xfs: Don't clear SGID when inheriting ACLs
xfs: free cowblocks and retry on buffered write ENOSPC
xfs: replace log_badcrc_factor knob with error injection tag
xfs: convert drop_writes to use the errortag mechanism
xfs: remove unneeded parameter from XFS_TEST_ERROR
xfs: expose errortag knobs via sysfs
xfs: make errortag a per-mountpoint structure
xfs: free uncommitted transactions during log recovery
xfs: don't allow bmap on rt files
...
Pull core block/IO updates from Jens Axboe:
"This is the main pull request for the block layer for 4.13. Not a huge
round in terms of features, but there's a lot of churn related to some
core cleanups.
Note this depends on the UUID tree pull request, that Christoph
already sent out.
This pull request contains:
- A series from Christoph, unifying the error/stats codes in the
block layer. We now use blk_status_t everywhere, instead of using
different schemes for different places.
- Also from Christoph, some cleanups around request allocation and IO
scheduler interactions in blk-mq.
- And yet another series from Christoph, cleaning up how we handle
and do bounce buffering in the block layer.
- A blk-mq debugfs series from Bart, further improving on the support
we have for exporting internal information to aid debugging IO
hangs or stalls.
- Also from Bart, a series that cleans up the request initialization
differences across types of devices.
- A series from Goldwyn Rodrigues, allowing the block layer to return
failure if we will block and the user asked for non-blocking.
- Patch from Hannes for supporting setting loop devices block size to
that of the underlying device.
- Two series of patches from Javier, fixing various issues with
lightnvm, particular around pblk.
- A series from me, adding support for write hints. This comes with
NVMe support as well, so applications can help guide data placement
on flash to improve performance, latencies, and write
amplification.
- A series from Ming, improving and hardening blk-mq support for
stopping/starting and quiescing hardware queues.
- Two pull requests for NVMe updates. Nothing major on the feature
side, but lots of cleanups and bug fixes. From the usual crew.
- A series from Neil Brown, greatly improving the bio rescue set
support. Most notably, this kills the bio rescue work queues, if we
don't really need them.
- Lots of other little bug fixes that are all over the place"
* 'for-4.13/block' of git://git.kernel.dk/linux-block: (217 commits)
lightnvm: pblk: set line bitmap check under debug
lightnvm: pblk: verify that cache read is still valid
lightnvm: pblk: add initialization check
lightnvm: pblk: remove target using async. I/Os
lightnvm: pblk: use vmalloc for GC data buffer
lightnvm: pblk: use right metadata buffer for recovery
lightnvm: pblk: schedule if data is not ready
lightnvm: pblk: remove unused return variable
lightnvm: pblk: fix double-free on pblk init
lightnvm: pblk: fix bad le64 assignations
nvme: Makefile: remove dead build rule
blk-mq: map all HWQ also in hyperthreaded system
nvmet-rdma: register ib_client to not deadlock in device removal
nvme_fc: fix error recovery on link down.
nvmet_fc: fix crashes on bad opcodes
nvme_fc: Fix crash when nvme controller connection fails.
nvme_fc: replace ioabort msleep loop with completion
nvme_fc: fix double calls to nvme_cleanup_cmd()
nvme-fabrics: verify that a controller returns the correct NQN
nvme: simplify nvme_dev_attrs_are_visible
...
This is a purely mechanical patch that removes the private
__{u,}int{8,16,32,64}_t typedefs in favor of using the system
{u,}int{8,16,32,64}_t typedefs. This is the sed script used to perform
the transformation and fix the resulting whitespace and indentation
errors:
s/typedef\t__uint8_t/typedef __uint8_t\t/g
s/typedef\t__uint/typedef __uint/g
s/typedef\t__int\([0-9]*\)_t/typedef int\1_t\t/g
s/__uint8_t\t/__uint8_t\t\t/g
s/__uint/uint/g
s/__int\([0-9]*\)_t\t/__int\1_t\t\t/g
s/__int/int/g
/^typedef.*int[0-9]*_t;$/d
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reclaim during quotacheck can lead to deadlocks on the dquot flush
lock:
- Quotacheck populates a local delwri queue with the physical dquot
buffers.
- Quotacheck performs the xfs_qm_dqusage_adjust() bulkstat and
dirties all of the dquots.
- Reclaim kicks in and attempts to flush a dquot whose buffer is
already queud on the quotacheck queue. The flush succeeds but
queueing to the reclaim delwri queue fails as the backing buffer is
already queued. The flush unlock is now deferred to I/O completion
of the buffer from the quotacheck queue.
- The dqadjust bulkstat continues and dirties the recently flushed
dquot once again.
- Quotacheck proceeds to the xfs_qm_flush_one() walk which requires
the flush lock to update the backing buffers with the in-core
recalculated values. It deadlocks on the redirtied dquot as the
flush lock was already acquired by reclaim, but the buffer resides
on the local delwri queue which isn't submitted until the end of
quotacheck.
This is reproduced by running quotacheck on a filesystem with a
couple million inodes in low memory (512MB-1GB) situations. This is
a regression as of commit 43ff2122e6 ("xfs: on-stack delayed write
buffer lists"), which removed a trylock and buffer I/O submission
from the quotacheck dquot flush sequence.
Quotacheck first resets and collects the physical dquot buffers in a
delwri queue. Then, it traverses the filesystem inodes via bulkstat,
updates the in-core dquots, flushes the corrected dquots to the
backing buffers and finally submits the delwri queue for I/O. Since
the backing buffers are queued across the entire quotacheck
operation, dquot reclaim cannot possibly complete a dquot flush
before quotacheck completes.
Therefore, quotacheck must submit the buffer for I/O in order to
cycle the flush lock and flush the dirty in-core dquot to the
buffer. Add a delwri queue buffer push mechanism to submit an
individual buffer for I/O without losing the delwri queue status and
use it from quotacheck to avoid the deadlock. This restores
quotacheck behavior to as before the regression was introduced.
Reported-by: Martin Svec <martin.svec@zoner.cz>
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>
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Merge tag 'v4.12-rc5' into for-4.13/block
We've already got a few conflicts and upcoming work depends on some of the
changes that have gone into mainline as regression fixes for this series.
Pull in 4.12-rc5 to resolve these conflicts and make it easier on down stream
trees to continue working on 4.13 changes.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace bi_error with a new bi_status to allow for a clear conversion.
Note that device mapper overloaded bi_error with a private value, which
we'll have to keep arround at least for now and thus propagate to a
proper blk_status_t value.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
The 0-day kernel test robot reports assertion failures on
!CONFIG_SMP kernels due to failed spin_is_locked() checks. As it
turns out, spin_is_locked() is hardcoded to return zero on
!CONFIG_SMP kernels and so this function cannot be relied on to
verify spinlock state in this configuration.
To avoid this problem, replace the associated asserts with lockdep
variants that do the right thing regardless of kernel configuration.
Drop the one assert that checks for an unlocked lock as there is no
suitable lockdep variant for that case. This moves the spinlock
checks from XFS debug code to lockdep, but generally provides the
same level of protection.
Reported-by: kbuild test robot <fengguang.wu@intel.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>
We've had user reports of unmount hangs in xfs_wait_buftarg() that
analysis shows is due to btp->bt_io_count == -1. bt_io_count
represents the count of in-flight asynchronous buffers and thus
should always be >= 0. xfs_wait_buftarg() waits for this value to
stabilize to zero in order to ensure that all untracked (with
respect to the lru) buffers have completed I/O processing before
unmount proceeds to tear down in-core data structures.
The value of -1 implies an I/O accounting decrement race. Indeed,
the fact that xfs_buf_ioacct_dec() is called from xfs_buf_rele()
(where the buffer lock is no longer held) means that bp->b_flags can
be updated from an unsafe context. While a user-level reproducer is
currently not available, some intrusive hacks to run racing buffer
lookups/ioacct/releases from multiple threads was used to
successfully manufacture this problem.
Existing callers do not expect to acquire the buffer lock from
xfs_buf_rele(). Therefore, we can not safely update ->b_flags from
this context. It turns out that we already have separate buffer
state bits and associated serialization for dealing with buffer LRU
state in the form of ->b_state and ->b_lock. Therefore, replace the
_XBF_IN_FLIGHT flag with a ->b_state variant, update the I/O
accounting wrappers appropriately and make sure they are used with
the correct locking. This ensures that buffer in-flight state can be
modified at buffer release time without racing with modifications
from a buffer lock holder.
Fixes: 9c7504aa72 ("xfs: track and serialize in-flight async buffers against unmount")
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Libor Pechacek <lpechacek@suse.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
- various code cleanups
- introduce GETFSMAP ioctl
- various refactoring
- avoid dio reads past eof
- fix memory corruption and other errors with fragmented directory blocks
- fix accidental userspace memory corruptions
- publish fs uuid in superblock
- make fstrim terminatable
- fix race between quotaoff and in-core inode creation
- Avoid use-after-free when finishing up w/ buffer heads
- Reserve enough space to handle bmap tree resizing during cow remap
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Merge tag 'xfs-4.12-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull xfs updates from Darrick Wong:
"Here are the XFS changes for 4.12. The big new feature for this
release is the new space mapping ioctl that we've been discussing
since LSF2016, but other than that most of the patches are larger bug
fixes, memory corruption prevention, and other cleanups.
Summary:
- various code cleanups
- introduce GETFSMAP ioctl
- various refactoring
- avoid dio reads past eof
- fix memory corruption and other errors with fragmented directory blocks
- fix accidental userspace memory corruptions
- publish fs uuid in superblock
- make fstrim terminatable
- fix race between quotaoff and in-core inode creation
- avoid use-after-free when finishing up w/ buffer heads
- reserve enough space to handle bmap tree resizing during cow remap"
* tag 'xfs-4.12-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (53 commits)
xfs: fix use-after-free in xfs_finish_page_writeback
xfs: reserve enough blocks to handle btree splits when remapping
xfs: wait on new inodes during quotaoff dquot release
xfs: update ag iterator to support wait on new inodes
xfs: support ability to wait on new inodes
xfs: publish UUID in struct super_block
xfs: Allow user to kill fstrim process
xfs: better log intent item refcount checking
xfs: fix up quotacheck buffer list error handling
xfs: remove xfs_trans_ail_delete_bulk
xfs: don't use bool values in trace buffers
xfs: fix getfsmap userspace memory corruption while setting OF_LAST
xfs: fix __user annotations for xfs_ioc_getfsmap
xfs: corruption needs to respect endianess too!
xfs: use NULL instead of 0 to initialize a pointer in xfs_ioc_getfsmap
xfs: use NULL instead of 0 to initialize a pointer in xfs_getfsmap
xfs: simplify validation of the unwritten extent bit
xfs: remove unused values from xfs_exntst_t
xfs: remove the unused XFS_MAXLINK_1 define
xfs: more do_div cleanups
...
kmem_zalloc_large and _xfs_buf_map_pages use memalloc_noio_{save,restore}
API to prevent from reclaim recursion into the fs because vmalloc can
invoke unconditional GFP_KERNEL allocations and these functions might be
called from the NOFS contexts. The memalloc_noio_save will enforce
GFP_NOIO context which is even weaker than GFP_NOFS and that seems to be
unnecessary. Let's use memalloc_nofs_{save,restore} instead as it
should provide exactly what we need here - implicit GFP_NOFS context.
Link: http://lkml.kernel.org/r/20170306131408.9828-6-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Nikolay Borisov <nborisov@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The quotacheck error handling of the delwri buffer list assumes the
resident buffers are locked and doesn't clear the _XBF_DELWRI_Q flag
on the buffers that are dequeued. This can lead to assert failures
on buffer release and possibly other locking problems.
Move this code to a delwri queue cancel helper function to
encapsulate the logic required to properly release buffers from a
delwri queue. Update the helper to clear the delwri queue flag and
call it from quotacheck.
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>
Update the .c files that depend on these APIs.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
blk_get_backing_dev_info() is now a simple dereference. Remove that
function and simplify some code around that.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
If we try to allocate memory pages to back an xfs_buf that we're trying
to read, it's possible that we'll be so short on memory that the page
allocation fails. For a blocking read we'll just wait, but for
readahead we simply dump all the pages we've collected so far.
Unfortunately, after dumping the pages we neglect to clear the
_XBF_PAGES state, which means that the subsequent call to xfs_buf_free
thinks that b_pages still points to pages we own. It then double-frees
the b_pages pages.
This results in screaming about negative page refcounts from the memory
manager, which xfs oughtn't be triggering. To reproduce this case,
mount a filesystem where the size of the inodes far outweighs the
availalble memory (a ~500M inode filesystem on a VM with 300MB memory
did the trick here) and run bulkstat in parallel with other memory
eating processes to put a huge load on the system. The "check summary"
phase of xfs_scrub also works for this purpose.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Contained in this update:
- DAX PMD vaults via iomap infrastructure
- Direct-io support in iomap infrastructure
- removal of now-redundant XFS inode iolock, replaced with VFS i_rwsem
- synchronisation with fixes and changes in userspace libxfs code
- extent tree lookup helpers
- lots of little corruption detection improvements to verifiers
- optimised CRC calculations
- faster buffer cache lookups
- deprecation of barrier/nobarrier mount options - we always use
REQ_FUA/REQ_FLUSH where appropriate for data integrity now
- cleanups to speculative preallocation
- miscellaneous minor bug fixes and cleanups
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Merge tag 'xfs-for-linus-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs
Pull xfs updates from Dave Chinner:
"There is quite a varied bunch of stuff in this update, and some of it
you will have already merged through the ext4 tree which imported the
dax-4.10-iomap-pmd topic branch from the XFS tree.
There is also a new direct IO implementation that uses the iomap
infrastructure. It's much simpler, faster, and has lower IO latency
than the existing direct IO infrastructure.
Summary:
- DAX PMD faults via iomap infrastructure
- Direct-io support in iomap infrastructure
- removal of now-redundant XFS inode iolock, replaced with VFS
i_rwsem
- synchronisation with fixes and changes in userspace libxfs code
- extent tree lookup helpers
- lots of little corruption detection improvements to verifiers
- optimised CRC calculations
- faster buffer cache lookups
- deprecation of barrier/nobarrier mount options - we always use
REQ_FUA/REQ_FLUSH where appropriate for data integrity now
- cleanups to speculative preallocation
- miscellaneous minor bug fixes and cleanups"
* tag 'xfs-for-linus-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (63 commits)
xfs: nuke unused tracepoint definitions
xfs: use GPF_NOFS when allocating btree cursors
xfs: use xfs_vn_setattr_size to check on new size
xfs: deprecate barrier/nobarrier mount option
xfs: Always flush caches when integrity is required
xfs: ignore leaf attr ichdr.count in verifier during log replay
xfs: use rhashtable to track buffer cache
xfs: optimise CRC updates
xfs: make xfs btree stats less huge
xfs: don't cap maximum dedupe request length
xfs: don't allow di_size with high bit set
xfs: error out if trying to add attrs and anextents > 0
xfs: don't crash if reading a directory results in an unexpected hole
xfs: complain if we don't get nextents bmap records
xfs: check for bogus values in btree block headers
xfs: forbid AG btrees with level == 0
xfs: several xattr functions can be void
xfs: handle cow fork in xfs_bmap_trace_exlist
xfs: pass state not whichfork to trace_xfs_extlist
xfs: Move AGI buffer type setting to xfs_read_agi
...
There is no reason anymore for not issuing device integrity
operations when teh filesystem requires ordering or data integrity
guarantees. We should always issue cache flushes and FUA writes
where necessary and let the underlying storage optimise them as
necessary for correct integrity operation.
Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
On filesystems with a lot of metadata and in metadata intensive workloads
xfs_buf_find() is showing up at the top of the CPU cycles trace. Most of
the CPU time is spent on CPU cache misses while traversing the rbtree.
As the buffer cache does not need any kind of ordering, but fast lookups
a hashtable is the natural data structure to use. The rhashtable
infrastructure provides a self-scaling hashtable implementation and
allows lookups to proceed while the table is going through a resize
operation.
This reduces the CPU-time spent for the lookups to 1/3 even for small
filesystems with a relatively small number of cached buffers, with
possibly much larger gains on higher loaded filesystems.
[dchinner: reduce minimum hash size to an acceptable size for large
filesystems with many AGs with no active use.]
[dchinner: remove stale rbtree asserts.]
[dchinner: use xfs_buf_map for compare function argument.]
[dchinner: make functions static.]
[dchinner: remove redundant comments.]
Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly. Where applicable this also drops usage of the
bio_set_op_attrs wrapper.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
xfs_wait_buftarg() waits for all pending I/O, drains the ioend
completion workqueue and walks the LRU until all buffers in the cache
have been released. This is traditionally an unmount operation` but the
mechanism is also reused during filesystem freeze.
xfs_wait_buftarg() invokes drain_workqueue() as part of the quiesce,
which is intended more for a shutdown sequence in that it indicates to
the queue that new operations are not expected once the drain has begun.
New work jobs after this point result in a WARN_ON_ONCE() and are
otherwise dropped.
With filesystem freeze, however, read operations are allowed and can
proceed during or after the workqueue drain. If such a read occurs
during the drain sequence, the workqueue infrastructure complains about
the queued ioend completion work item and drops it on the floor. As a
result, the buffer remains on the LRU and the freeze never completes.
Despite the fact that the overall buffer cache cleanup is not necessary
during freeze, fix up this operation such that it is safe to invoke
during non-unmount quiesce operations. Replace the drain_workqueue()
call with flush_workqueue(), which runs a similar serialization on
pending workqueue jobs without causing new jobs to be dropped. This is
safe for unmount as unmount independently locks out new operations by
the time xfs_wait_buftarg() is invoked.
cc: <stable@vger.kernel.org>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The buffer I/O accounting mechanism tracks async buffers under I/O. As
an optimization, the buffer I/O count is incremented only once on the
first async I/O for a given hold cycle of a buffer and decremented once
the buffer is released to the LRU (or freed).
xfs_buf_ioacct_dec() has an ASSERT() check for an XBF_ASYNC buffer, but
we have one or two corner cases where a buffer can be submitted for I/O
multiple times via different methods in a single hold cycle. If an async
I/O occurs first, the I/O count is incremented. If a sync I/O occurs
before the hold count drops, XBF_ASYNC is cleared by the time the I/O
count is decremented.
Remove the async assert check from xfs_buf_ioacct_dec() as this is a
perfectly valid scenario. For the purposes of I/O accounting, we really
only care about the buffer async state at I/O submission time.
Discovered-and-analyzed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Changes in this update:
o generic iomap based IO path infrastructure
o generic iomap based fiemap implementation
o xfs iomap based Io path implementation
o buffer error handling fixes
o tracking of in flight buffer IO for unmount serialisation
o direct IO and DAX io path separation and simplification
o shortform directory format definition changes for wider platform compatibility
o various buffer cache fixes
o cleanups in preparation for rmap merge
o error injection cleanups and fixes
o log item format buffer memory allocation restructuring to prevent rare OOM
reclaim deadlocks
o sparse inode chunks are now fully supported.
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Merge tag 'xfs-for-linus-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs
Pull xfs updates from Dave Chinner:
"The major addition is the new iomap based block mapping
infrastructure. We've been kicking this about locally for years, but
there are other filesystems want to use it too (e.g. gfs2). Now it
is fully working, reviewed and ready for merge and be used by other
filesystems.
There are a lot of other fixes and cleanups in the tree, but those are
XFS internal things and none are of the scale or visibility of the
iomap changes. See below for details.
I am likely to send another pull request next week - we're just about
ready to merge some new functionality (on disk block->owner reverse
mapping infrastructure), but that's a huge chunk of code (74 files
changed, 7283 insertions(+), 1114 deletions(-)) so I'm keeping that
separate to all the "normal" pull request changes so they don't get
lost in the noise.
Summary of changes in this update:
- generic iomap based IO path infrastructure
- generic iomap based fiemap implementation
- xfs iomap based Io path implementation
- buffer error handling fixes
- tracking of in flight buffer IO for unmount serialisation
- direct IO and DAX io path separation and simplification
- shortform directory format definition changes for wider platform
compatibility
- various buffer cache fixes
- cleanups in preparation for rmap merge
- error injection cleanups and fixes
- log item format buffer memory allocation restructuring to prevent
rare OOM reclaim deadlocks
- sparse inode chunks are now fully supported"
* tag 'xfs-for-linus-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (53 commits)
xfs: remove EXPERIMENTAL tag from sparse inode feature
xfs: bufferhead chains are invalid after end_page_writeback
xfs: allocate log vector buffers outside CIL context lock
libxfs: directory node splitting does not have an extra block
xfs: remove dax code from object file when disabled
xfs: skip dirty pages in ->releasepage()
xfs: remove __arch_pack
xfs: kill xfs_dir2_inou_t
xfs: kill xfs_dir2_sf_off_t
xfs: split direct I/O and DAX path
xfs: direct calls in the direct I/O path
xfs: stop using generic_file_read_iter for direct I/O
xfs: split xfs_file_read_iter into buffered and direct I/O helpers
xfs: remove s_maxbytes enforcement in xfs_file_read_iter
xfs: kill ioflags
xfs: don't pass ioflags around in the ioctl path
xfs: track and serialize in-flight async buffers against unmount
xfs: exclude never-released buffers from buftarg I/O accounting
xfs: don't reset b_retries to 0 on every failure
xfs: remove extraneous buffer flag changes
...
Newly allocated XFS metadata buffers are added to the LRU once the hold
count is released, which typically occurs after I/O completion. There is
no other mechanism at current that tracks the existence or I/O state of
a new buffer. Further, readahead I/O tends to be submitted
asynchronously by nature, which means the I/O can remain in flight and
actually complete long after the calling context is gone. This means
that file descriptors or any other holds on the filesystem can be
released, allowing the filesystem to be unmounted while I/O is still in
flight. When I/O completion occurs, core data structures may have been
freed, causing completion to run into invalid memory accesses and likely
to panic.
This problem is reproduced on XFS via directory readahead. A filesystem
is mounted, a directory is opened/closed and the filesystem immediately
unmounted. The open/close cycle triggers a directory readahead that if
delayed long enough, runs buffer I/O completion after the unmount has
completed.
To address this problem, add a mechanism to track all in-flight,
asynchronous buffers using per-cpu counters in the buftarg. The buffer
is accounted on the first I/O submission after the current reference is
acquired and unaccounted once the buffer is returned to the LRU or
freed. Update xfs_wait_buftarg() to wait on all in-flight I/O before
walking the LRU list. Once in-flight I/O has completed and the workqueue
has drained, all new buffers should have been released onto the LRU.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
The upcoming buftarg I/O accounting mechanism maintains a count of
all buffers that have undergone I/O in the current hold-release
cycle. Certain buffers associated with core infrastructure (e.g.,
the xfs_mount superblock buffer, log buffers) are never released,
however. This means that accounting I/O submission on such buffers
elevates the buftarg count indefinitely and could lead to lockup on
unmount.
Define a new buffer flag to explicitly exclude buffers from buftarg
I/O accounting. Set the flag on the superblock and associated log
buffers.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
