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| author | Junichi Nomura <j-nomura@ce.jp.nec.com> | 2015-11-06 03:47:23 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-11-06 04:34:48 +0100 |
| commit | aa750fd71c242dba02ee2034e15fbd7d0cdb2461 (patch) | |
| tree | e050f066844b2e18c2618f57376ab9d576a23b54 /fs | |
| parent | mm/compaction.c: add an is_via_compact_memory() helper (diff) | |
| download | linux-aa750fd71c242dba02ee2034e15fbd7d0cdb2461.tar.xz linux-aa750fd71c242dba02ee2034e15fbd7d0cdb2461.zip | |
mm/filemap.c: make global sync not clear error status of individual inodes
filemap_fdatawait() is a function to wait for on-going writeback to
complete but also consume and clear error status of the mapping set during
writeback.
The latter functionality is critical for applications to detect writeback
error with system calls like fsync(2)/fdatasync(2).
However filemap_fdatawait() is also used by sync(2) or FIFREEZE ioctl,
which don't check error status of individual mappings.
As a result, fsync() may not be able to detect writeback error if events
happen in the following order:
Application System admin
----------------------------------------------------------
write data on page cache
Run sync command
writeback completes with error
filemap_fdatawait() clears error
fsync returns success
(but the data is not on disk)
This patch adds filemap_fdatawait_keep_errors() for call sites where
writeback error is not handled so that they don't clear error status.
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: Fengguang Wu <fengguang.wu@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/fs-writeback.c | 7 | ||||
| -rw-r--r-- | fs/sync.c | 7 |
2 files changed, 12 insertions, 2 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 7378169e90be..206a68b1db1a 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -2149,7 +2149,12 @@ static void wait_sb_inodes(struct super_block *sb) iput(old_inode); old_inode = inode; - filemap_fdatawait(mapping); + /* + * We keep the error status of individual mapping so that + * applications can catch the writeback error using fsync(2). + * See filemap_fdatawait_keep_errors() for details. + */ + filemap_fdatawait_keep_errors(mapping); cond_resched(); diff --git a/fs/sync.c b/fs/sync.c index fbc98ee62044..4ec430ae2b0d 100644 --- a/fs/sync.c +++ b/fs/sync.c @@ -86,7 +86,12 @@ static void fdatawrite_one_bdev(struct block_device *bdev, void *arg) static void fdatawait_one_bdev(struct block_device *bdev, void *arg) { - filemap_fdatawait(bdev->bd_inode->i_mapping); + /* + * We keep the error status of individual mapping so that + * applications can catch the writeback error using fsync(2). + * See filemap_fdatawait_keep_errors() for details. + */ + filemap_fdatawait_keep_errors(bdev->bd_inode->i_mapping); } /* |