dio_fsync_thread must call filemap_fdatawrite() before file->f_op->fsync().
Otherwise:
8,0 6 82 0.003095587 12328 D WS 441706496 + 512 [ploop19054]
8,0 6 83 0.003103726 12328 D WS 441707008 + 512 [ploop19054]
8,0 6 84 0.003108627 12328 D WS 441707520 + 512 [ploop19054]
8,0 6 85 0.003113176 12328 D WS 441708032 + 512 [ploop19054]
...
8,0 6 102 0.003149386 1299 D WS 3950526248 + 24 [jbd2/dm-1-8]
...
8,0 6 103 0.003305550 0 C WS 441706496 + 512 [0]
8,0 6 104 0.003458057 0 C WS 441707008 + 512 [0]
8,0 6 105 0.003608325 0 C WS 441707520 + 512 [0]
8,0 6 106 0.003758297 0 C WS 441708032 + 512 [0]
8,0 6 107 0.003794543 0 C WS 3950526248 + 24 [0]
And if the node crashes (or reboot happens) after last dispatch, journal data
may come to the disk while user bulk data -- not. The result would be ploop
image corruption.
The patch re-arranges the sequence of calls to make it safe and natural (the
same way as in vfs_fsync_range()).
Signed-off-by: Maxim Patlasov <mpatla...@parallels.com>
---
drivers/block/ploop/io_direct.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/block/ploop/io_direct.c b/drivers/block/ploop/io_direct.c
index babc940..c18d2f0 100644
--- a/drivers/block/ploop/io_direct.c
+++ b/drivers/block/ploop/io_direct.c
@@ -735,14 +735,13 @@ static int dio_fsync_thread(void * data)
spin_unlock_irq(&plo->lock);
/* filemap_fdatawrite() has been made already */
+ filemap_fdatawait(io->files.mapping);
err = 0;
if (io->files.file->f_op->fsync)
err = io->files.file->f_op->FOP_FSYNC(io->files.file,
0);
- filemap_fdatawait(io->files.mapping);
-
/* Do we need to invalidate page cache? Not really,
* because we use it only to create full new pages,
* which we overwrite completely. Probably, we should
--
1.9.3
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