On Tue, 20 Apr 2010 12:41:53 +1000 Dave Chinner <david@xxxxxxxxxxxxx> wrote: > 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 > Bug. AFAIT it's a regression introduced by : commit 17bc6c30cf6bfffd816bdc53682dd46fc34a2cf4 : Author: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> : AuthorDate: Thu Oct 16 10:09:17 2008 -0400 : Commit: Theodore Ts'o <tytso@xxxxxxx> : CommitDate: Thu Oct 16 10:09:17 2008 -0400 : : vfs: Add no_nrwrite_index_update writeback control flag I suggest that what you do here is remove the local `nr_to_write' from write_cache_pages() and go back to directly using wbc->nr_to_write within the loop. And thus we restore the convention that if the fs writes back more than a single page, it subtracts (nr_written - 1) from wbc->nr_to_write. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
