[PATCH AUTOSEL 5.1 168/219] bcache: check CACHE_SET_IO_DISABLE in allocator code

Sasha Levin
2019-07-15T15:01:56Z

From: Coly Li <colyli@suse.de>

[ Upstream commit e775339e1ae1205b47d94881db124c11385e597c ]

If CACHE_SET_IO_DISABLE of a cache set flag is set by too many I/O
errors, currently allocator routines can still continue allocate
space which may introduce inconsistent metadata state.

This patch checkes CACHE_SET_IO_DISABLE bit in following allocator
routines,
- bch_bucket_alloc()
- __bch_bucket_alloc_set()
Once CACHE_SET_IO_DISABLE is set on cache set, the allocator routines
may reject allocation request earlier to avoid potential inconsistent
metadata.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/md/bcache/alloc.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index f8986effcb50..6f776823b9ba 100644
--- a/drivers/md/bcache/alloc.c
+++ b/drivers/md/bcache/alloc.c
@@ -393,6 +393,11 @@ long bch_bucket_alloc(struct cache *ca, unsigned int reserve, bool wait)
struct bucket *b;
long r;

+
+ /* No allocation if CACHE_SET_IO_DISABLE bit is set */
+ if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &ca->set->flags)))
+ return -1;
+
/* fastpath */
if (fifo_pop(&ca->free[RESERVE_NONE], r) ||
fifo_pop(&ca->free[reserve], r))
@@ -484,6 +489,10 @@ int __bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve,
{
int i;

+ /* No allocation if CACHE_SET_IO_DISABLE bit is set */
+ if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &c->flags)))
+ return -1;
+
lockdep_assert_held(&c->bucket_lock);
BUG_ON(!n || n > c->caches_loaded || n > MAX_CACHES_PER_SET);

--
2.20.1