Skip to content

K
Kernel

openeuler / Kernel
1 年多 前同步成功

通知 8
Star 0
Fork 0
K
Kernel
切换分支/标签
  1. 07 5月, 2020 5 次提交
  3. 19 3月, 2020 1 次提交
  5. 27 1月, 2020 1 次提交
  7. 17 1月, 2020 3 次提交
  9. 19 12月, 2019 1 次提交
  11. 19 11月, 2019 1 次提交
  13. 08 11月, 2019 1 次提交
  15. 27 8月, 2019 1 次提交
  17. 29 6月, 2019 7 次提交
  19. 15 4月, 2019 1 次提交
  21. 21 11月, 2018 1 次提交
  23. 29 9月, 2018 2 次提交
    • B
      xfs: refactor xfs_buf_log_item reference count handling · 95808459
      由 Brian Foster 提交于 
      The xfs_buf_log_item structure has a reference counter with slightly
tricky semantics. In the common case, a buffer is logged and
committed in a transaction, committed to the on-disk log (added to
the AIL) and then finally written back and removed from the AIL. The
bli refcount covers two potentially overlapping timeframes:

 1. the bli is held in an active transaction
 2. the bli is pinned by the log

The caveat to this approach is that the reference counter does not
purely dictate the lifetime of the bli. IOW, when a dirty buffer is
physically logged and unpinned, the bli refcount may go to zero as
the log item is inserted into the AIL. Only once the buffer is
written back can the bli finally be freed.

The above semantics means that it is not enough for the various
refcount decrementing contexts to release the bli on decrement to
zero. xfs_trans_brelse(), transaction commit (->iop_unlock()) and
unpin (->iop_unpin()) must all drop the associated reference and
make additional checks to determine if the current context is
responsible for freeing the item.

For example, if a transaction holds but does not dirty a particular
bli, the commit may drop the refcount to zero. If the bli itself is
clean, it is also not AIL resident and must be freed at this time.
The same is true for xfs_trans_brelse(). If the transaction dirties
a bli and then aborts or an unpin results in an abort due to a log
I/O error, the last reference count holder is expected to explicitly
remove the item from the AIL and release it (since an abort means
filesystem shutdown and metadata writeback will never occur).

This leads to fairly complex checks being replicated in a few
different places. Since ->iop_unlock() and xfs_trans_brelse() are
nearly identical, refactor the logic into a common helper that
implements and documents the semantics in one place. This patch does
not change behavior.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>
      95808459
    • B
      xfs: don't unlock invalidated buf on aborted tx commit · d9183105
      由 Brian Foster 提交于 
      xfstests generic/388,475 occasionally reproduce assertion failures
in xfs_buf_item_unpin() when the final bli reference is dropped on
an invalidated buffer and the buffer is not locked as it is expected
to be. Invalidated buffers should remain locked on transaction
commit until the final unpin, at which point the buffer is removed
from the AIL and the bli is freed since stale buffers are not
written back.

The assert failures are associated with filesystem shutdown,
typically due to log I/O errors injected by the test. The
problematic situation can occur if the shutdown happens to cause a
race between an active transaction that has invalidated a particular
buffer and an I/O error on a log buffer that contains the bli
associated with the same (now stale) buffer.

Both transaction and log contexts acquire a bli reference. If the
transaction has already invalidated the buffer by the time the I/O
error occurs and ends up aborting due to shutdown, the transaction
and log hold the last two references to a stale bli. If the
transaction cancel occurs first, it treats the buffer as non-stale
due to the aborted state: the bli reference is dropped and the
buffer is released/unlocked. The log buffer I/O error handling
eventually calls into xfs_buf_item_unpin(), drops the final
reference to the bli and treats it as stale. The buffer wasn't left
locked by xfs_buf_item_unlock(), however, so the assert fails and
the buffer is double unlocked. The latter problem is mitigated by
the fact that the fs is shutdown and no further damage is possible.

->iop_unlock() of an invalidated buffer should behave consistently
with respect to the bli refcount, regardless of aborted state. If
the refcount remains elevated on commit, we know the bli is awaiting
an unpin (since it can't be in another transaction) and will be
handled appropriately on log buffer completion. If the final bli
reference of an invalidated buffer is dropped in ->iop_unlock(), we
can assume the transaction has aborted because invalidation implies
a dirty transaction. In the non-abort case, the log would have
acquired a bli reference in ->iop_pin() and prevented bli release at
->iop_unlock() time. In the abort case the item must be freed and
buffer unlocked because it wasn't pinned by the log.

Rework xfs_buf_item_unlock() to simplify the currently circuitous
and duplicate logic and leave invalidated buffers locked based on
bli refcount, regardless of aborted state. This ensures that a
pinned, stale buffer is always found locked when eventually
unpinned.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>
      d9183105
  25. 09 6月, 2018 1 次提交
  27. 07 6月, 2018 1 次提交
    • D
      xfs: convert to SPDX license tags · 0b61f8a4
      由 Dave Chinner 提交于 
      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: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
      0b61f8a4
  29. 10 5月, 2018 3 次提交
  31. 12 3月, 2018 1 次提交
  33. 29 1月, 2018 3 次提交
  35. 02 9月, 2017 4 次提交
  37. 23 8月, 2017 2 次提交