diff options
| author | Artem Bityutskiy <Artem.Bityutskiy@nokia.com> | 2009-02-02 18:33:49 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-02-17 09:46:17 -0800 |
| commit | 7d120e20744a6a8d9dc3a3342bf9c385c44a3aaf (patch) | |
| tree | 53b3acb00b9f5611dfbab28efff5455698754571 /mm | |
| parent | c7e66cfbd26497e27a33a54d93d116095fc25512 (diff) | |
write-back: fix nr_to_write counter
commit dcf6a79dda5cc2a2bec183e50d829030c0972aaa upstream.
Commit 05fe478dd04e02fa230c305ab9b5616669821dd3 introduced some
@wbc->nr_to_write breakage.
It made the following changes:
1. Decrement wbc->nr_to_write instead of nr_to_write
2. Decrement wbc->nr_to_write _only_ if wbc->sync_mode == WB_SYNC_NONE
3. If synced nr_to_write pages, stop only if if wbc->sync_mode ==
WB_SYNC_NONE, otherwise keep going.
However, according to the commit message, the intention was to only make
change 3. Change 1 is a bug. Change 2 does not seem to be necessary,
and it breaks UBIFS expectations, so if needed, it should be done
separately later. And change 2 does not seem to be documented in the
commit message.
This patch does the following:
1. Undo changes 1 and 2
2. Add a comment explaining change 3 (it very useful to have comments
in _code_, not only in the commit).
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Acked-by: Nick Piggin <npiggin@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page-writeback.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 3831bab33180..345b5f7abb7b 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -985,13 +985,22 @@ continue_unlock: } } - if (wbc->sync_mode == WB_SYNC_NONE) { + if (wbc->nr_to_write > 0) wbc->nr_to_write--; - if (wbc->nr_to_write <= 0) { - done = 1; - break; - } + else if (wbc->sync_mode == WB_SYNC_NONE) { + /* + * We stop writing back only if we are not + * doing integrity sync. In case of integrity + * sync we have to keep going because someone + * may be concurrently dirtying pages, and we + * might have synced a lot of newly appeared + * dirty pages, but have not synced all of the + * old dirty pages. + */ + done = 1; + break; } + if (wbc->nonblocking && bdi_write_congested(bdi)) { wbc->encountered_congestion = 1; done = 1; |