From: Eric Sandeen Date: Sat, 28 Oct 2006 17:38:27 +0000 (-0700) Subject: [PATCH] jbd: journal_dirty_data re-check for unmapped buffers X-Git-Tag: v2.6.19-rc4~65 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f58a74dca88d48b0669609b4957f3dd757bdc898;p=pandora-kernel.git [PATCH] jbd: journal_dirty_data re-check for unmapped buffers When running several fsx's and other filesystem stress tests, we found cases where an unmapped buffer was still being sent to submit_bh by the ext3 dirty data journaling code. I saw this happen in two ways, both related to another thread doing a truncate which would unmap the buffer in question. Either we would get into journal_dirty_data with a bh which was already unmapped (although journal_dirty_data_fn had checked for this earlier, the state was not locked at that point), or it would get unmapped in the middle of journal_dirty_data when we dropped locks to call sync_dirty_buffer. By re-checking for mapped state after we've acquired the bh state lock, we should avoid these races. If we find a buffer which is no longer mapped, we essentially ignore it, because journal_unmap_buffer has already decided that this buffer can go away. I've also added tracepoints in these two cases, and made a couple other tracepoint changes that I found useful in debugging this. Signed-off-by: Eric Sandeen Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed