bcache: Fix an infinite loop in journal replay

When running with multiple cache devices, if one of the devices has a completely
empty journal but we'd already found some journal entries on a previosu device
we'd go into an infinite loop.

Change-Id: I1dcdc0d738192746de28f40e8b08825b0dea5e2b
Signed-off-by: Kent Overstreet <kmo@daterainc.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
index ead001c9bed8..fe080ad0e558 100644
--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -190,9 +190,12 @@ int bch_journal_read(struct cache_set *c, struct list_head *list)
                         if (read_bucket(l))
                                 goto bsearch;
 
-                if (list_empty(list))
+                /* no journal entries on this device? */
+                if (l == ca->sb.njournal_buckets)
                         continue;
 bsearch:
+                BUG_ON(list_empty(list));
+
                 /* Binary search */
                 m = l;
                 r = find_next_bit(bitmap, ca->sb.njournal_buckets, l + 1);