The patch titled writeback: fix nr_to_write counter has been added to the -mm tree. Its filename is writeback-fix-nr_to_write-counter.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: writeback: fix nr_to_write counter From: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx> Commit 05fe478dd04e02fa230c305ab9b5616669821dd3 ("mm: write_cache_pages integrity fix") introduced some @wbc->nr_to_write breakage. Here is the change from the commit: >--- a/mm/page-writeback.c >+++ b/mm/page-writeback.c >@@ -963,8 +963,10 @@ retry: > } > } > > if (--nr_to_write <= 0) > done = 1; > if (wbc->sync_mode == WB_SYNC_NONE) { > if (--wbc->nr_to_write <= 0) > done = 1; > } > if (wbc->nonblocking && bdi_write_congested(bdi)) { > wbc->encountered_congestion = 1; > done = 1 > } 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@xxxxxxxxx> Acked-by: Nick Piggin <npiggin@xxxxxxx> Cc: Dave Kleikamp <shaggy@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page-writeback.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff -puN mm/page-writeback.c~writeback-fix-nr_to_write-counter mm/page-writeback.c --- a/mm/page-writeback.c~writeback-fix-nr_to_write-counter +++ a/mm/page-writeback.c @@ -1051,13 +1051,22 @@ continue_unlock: } } - if (wbc->sync_mode == WB_SYNC_NONE) { - wbc->nr_to_write--; - if (wbc->nr_to_write <= 0) { - done = 1; - break; - } + if (nr_to_write > 0) + nr_to_write--; + 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; _ Patches currently in -mm which might be from Artem.Bityutskiy@xxxxxxxxx are origin.patch linux-next.patch writeback-fix-nr_to_write-counter.patch reiser4-vfs-add-super_operationssync_inodes-2.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html