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| author | Dave Chinner <dchinner@redhat.com> | 2012-03-22 09:15:11 +0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-02-15 23:20:10 +0400 |
| commit | 1c7a9417edf13a32244bba86cf8197073ebad9a7 (patch) | |
| tree | f59b4fb1f804d5bff67c29f77b98b11759e18e51 | |
| parent | 609365b9ea77703c6be6e3cae5d5f31fa54fef90 (diff) | |
| download | linux-1c7a9417edf13a32244bba86cf8197073ebad9a7.tar.xz | |
xfs: Account log unmount transaction correctly
commit 3948659e30808fbaa7673bbe89de2ae9769e20a7 upstream.
There have been a few reports of this warning appearing recently:
XFS (dm-4): xlog_space_left: head behind tail
tail_cycle = 129, tail_bytes = 20163072
GH cycle = 129, GH bytes = 20162880
The common cause appears to be lots of freeze and unfreeze cycles,
and the output from the warnings indicates that we are leaking
around 8 bytes of log space per freeze/unfreeze cycle.
When we freeze the filesystem, we write an unmount record and that
uses xlog_write directly - a special type of transaction,
effectively. What it doesn't do, however, is correctly account for
the log space it uses. The unmount record writes an 8 byte structure
with a special magic number into the log, and the space this
consumes is not accounted for in the log ticket tracking the
operation. Hence we leak 8 bytes every unmount record that is
written.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | fs/xfs/xfs_log.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 34817adf4b9e..10ca5e56351e 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -653,8 +653,9 @@ xfs_log_unmount_write(xfs_mount_t *mp) .lv_iovecp = ®, }; - /* remove inited flag */ + /* remove inited flag, and account for space used */ tic->t_flags = 0; + tic->t_curr_res -= sizeof(magic); error = xlog_write(log, &vec, tic, &lsn, NULL, XLOG_UNMOUNT_TRANS); /* |