[PATCH 4.19 125/271] bcache: check CACHE_SET_IO_DISABLE bit in bch_journal()

From: Greg Kroah-Hartman
Date: Thu Jul 25 2019 - 11:02:13 EST

[ Upstream commit 383ff2183ad16a8842d1fbd9dd3e1cbd66813e64 ]

When too many I/O errors happen on cache set and CACHE_SET_IO_DISABLE
bit is set, bch_journal() may continue to work because the journaling
bkey might be still in write set yet. The caller of bch_journal() may
believe the journal still work but the truth is in-memory journal write
set won't be written into cache device any more. This behavior may
introduce potential inconsistent metadata status.

This patch checks CACHE_SET_IO_DISABLE bit at the head of bch_journal(),
if the bit is set, bch_journal() returns NULL immediately to notice
caller to know journal does not work.

Signed-off-by: Coly Li <colyli@xxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/md/bcache/journal.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
index f880e5eba8dd..8d4d63b51553 100644
--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -810,6 +810,10 @@ atomic_t *bch_journal(struct cache_set *c,
struct journal_write *w;
atomic_t *ret;

+ /* No journaling if CACHE_SET_IO_DISABLE set already */
+ if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &c->flags)))
+ return NULL;
if (!CACHE_SYNC(&c->sb))
return NULL;