path: root/mm/filemap.c
diff options
authorHisashi Hifumi <>2008-09-02 14:35:40 -0700
committerLinus Torvalds <>2008-09-02 19:21:37 -0700
commit6ccfa806a9cfbbf1cd43d5b6aa47ef2c0eb518fd (patch)
treedd3f17e1aebc802b147627a4151add363f39b77c /mm/filemap.c
parent344c790e3821dac37eb742ddd0b611a300f78b9a (diff)
VFS: fix dio write returning EIO when try_to_release_page fails
Dio write returns EIO when try_to_release_page fails because bh is still referenced. The patch commit 3f31fddfa26b7594b44ff2b34f9a04ba409e0f91 Author: Mingming Cao <> Date: Fri Jul 25 01:46:22 2008 -0700 jbd: fix race between free buffer and commit transaction was merged into 2.6.27-rc1, but I noticed that this patch is not enough to fix the race. I did fsstress test heavily to 2.6.27-rc1, and found that dio write still sometimes got EIO through this test. The patch above fixed race between freeing buffer(dio) and committing transaction(jbd) but I discovered that there is another race, freeing buffer(dio) and ext3/4_ordered_writepage. : background_writeout() ->write_cache_pages() ->ext3_ordered_writepage() walk_page_buffers() -> take a bh ref block_write_full_page() -> unlock_page : <- end_page_writeback : <- race! (dio write->try_to_release_page fails) walk_page_buffers() ->release a bh ref ext3_ordered_writepage holds bh ref and does unlock_page remaining taking a bh ref, so this causes the race and failure of try_to_release_page. To fix this race, I used the approach of falling back to buffered writes if try_to_release_page() fails on a page. [ cleanups] Signed-off-by: Hisashi Hifumi <> Cc: Chris Mason <> Cc: Jan Kara <> Cc: Mingming Cao <> Cc: Zach Brown <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'mm/filemap.c')
1 files changed, 9 insertions, 2 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 54e96865085..876bc595d0f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2129,13 +2129,20 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
* After a write we want buffered reads to be sure to go to disk to get
* the new data. We invalidate clean cached page from the region we're
* about to write. We do this *before* the write so that we can return
- * -EIO without clobbering -EIOCBQUEUED from ->direct_IO().
+ * without clobbering -EIOCBQUEUED from ->direct_IO().
if (mapping->nrpages) {
written = invalidate_inode_pages2_range(mapping,
pos >> PAGE_CACHE_SHIFT, end);
- if (written)
+ /*
+ * If a page can not be invalidated, return 0 to fall back
+ * to buffered write.
+ */
+ if (written) {
+ if (written == -EBUSY)
+ return 0;
goto out;
+ }
written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs);