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authorChris Mason <mason@suse.com>2006-02-01 03:06:47 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-01 08:53:26 -0800
commitd62b1b87a7d1c3a21dddabed4251763090be3182 (patch)
tree52d563a2af8bde77c9e4638e3636c8cd3bb0c01e /fs/reiserfs/journal.c
parentec191574b9c3cb7bfb95e4f803b63f7c8dc52690 (diff)
downloadop-kernel-dev-d62b1b87a7d1c3a21dddabed4251763090be3182.zip
op-kernel-dev-d62b1b87a7d1c3a21dddabed4251763090be3182.tar.gz
[PATCH] resierfs: fix reiserfs_invalidatepage race against data=ordered
After a transaction has closed but before it has finished commit, there is a window where data=ordered mode requires invalidatepage to pin pages instead of freeing them. This patch fixes a race between the invalidatepage checks and data=ordered writeback, and it also adds a check to the reiserfs write_ordered_buffers routines to write any anonymous buffers that were dirtied after its first writeback loop. That bug works like this: proc1: transaction closes and a new one starts proc1: write_ordered_buffers starts processing data=ordered list proc1: buffer A is cleaned and written proc2: buffer A is dirtied by another process proc2: File is truncated to zero, page A goes through invalidatepage proc2: reiserfs_invalidatepage sees dirty buffer A with reiserfs journal head, pins it proc1: write_ordered_buffers frees the journal head on buffer A At this point, buffer A stays dirty forever Signed-off-by: Chris Mason <mason@suse.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/reiserfs/journal.c')
-rw-r--r--fs/reiserfs/journal.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index 2d04efb..bc8fe96 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -877,6 +877,19 @@ static int write_ordered_buffers(spinlock_t * lock,
if (!buffer_uptodate(bh)) {
ret = -EIO;
}
+ /* ugly interaction with invalidatepage here.
+ * reiserfs_invalidate_page will pin any buffer that has a valid
+ * journal head from an older transaction. If someone else sets
+ * our buffer dirty after we write it in the first loop, and
+ * then someone truncates the page away, nobody will ever write
+ * the buffer. We're safe if we write the page one last time
+ * after freeing the journal header.
+ */
+ if (buffer_dirty(bh) && unlikely(bh->b_page->mapping == NULL)) {
+ spin_unlock(lock);
+ ll_rw_block(WRITE, 1, &bh);
+ spin_lock(lock);
+ }
put_bh(bh);
cond_resched_lock(lock);
}
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