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| author | Dave Chinner <dchinner@redhat.com> | 2010-06-09 04:37:18 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-06-09 05:12:44 +0400 |
| commit | 0b5649278e39a068aaf91399941bab1b4a4a3cc2 (patch) | |
| tree | 3fd2c782385137f5b135c07149de772e207fdaf8 /fs/nilfs2/dat.c | |
| parent | 8d7458daea2a6809d32418bf489b949d23de99ea (diff) | |
| download | linux-0b5649278e39a068aaf91399941bab1b4a4a3cc2.tar.xz | |
writeback: pay attention to wbc->nr_to_write in write_cache_pages
If a filesystem writes more than one page in ->writepage, write_cache_pages
fails to notice this and continues to attempt writeback when wbc->nr_to_write
has gone negative - this trace was captured from XFS:
wbc_writeback_start: towrt=1024
wbc_writepage: towrt=1024
wbc_writepage: towrt=0
wbc_writepage: towrt=-1
wbc_writepage: towrt=-5
wbc_writepage: towrt=-21
wbc_writepage: towrt=-85
This has adverse effects on filesystem writeback behaviour. write_cache_pages()
needs to terminate after a certain number of pages are written, not after a
certain number of calls to ->writepage are made. This is a regression
introduced by 17bc6c30cf6bfffd816bdc53682dd46fc34a2cf4 ("vfs: Add
no_nrwrite_index_update writeback control flag"), but cannot be reverted
directly due to subsequent bug fixes that have gone in on top of it.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/nilfs2/dat.c')
0 files changed, 0 insertions, 0 deletions