3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kent Overstreet <k...@daterainc.com>

commit faa5673617656ee58369a3cfe4a312cfcdc59c81 upstream.

The journal replay code starts by finding something that looks like a
valid journal entry, then it does a binary search over the unchecked
region of the journal for the journal entries with the highest sequence
numbers.

Trouble is, the logic was wrong - journal_read_bucket() returns true if
it found journal entries we need, but if the range of journal entries
we're looking for loops around the end of the journal - in that case
journal_read_bucket() could return true when it hadn't found the highest
sequence number we'd seen yet, and in that case the binary search did
the wrong thing. Whoops.

Signed-off-by: Kent Overstreet <k...@daterainc.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/md/bcache/journal.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -182,9 +182,14 @@ bsearch:
                pr_debug("starting binary search, l %u r %u", l, r);
 
                while (l + 1 < r) {
+                       seq = list_entry(list->prev, struct journal_replay,
+                                        list)->j.seq;
+
                        m = (l + r) >> 1;
+                       read_bucket(m);
 
-                       if (read_bucket(m))
+                       if (seq != list_entry(list->prev, struct journal_replay,
+                                             list)->j.seq)
                                l = m;
                        else
                                r = m;


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to