linux-kernel - [PATCH 4.19 124/271] bcache: check CACHE_SET_IO

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Message-Id: <20190724191705.898378775@linuxfoundation.org>
Date:   Wed, 24 Jul 2019 21:19:53 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Coly Li <colyli@...e.de>,
        Jens Axboe <axboe@...nel.dk>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 124/271] bcache: check CACHE_SET_IO_DISABLE in allocator code

[ 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@...e.de>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.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 de85b3af3b39..9c3beb1e382b 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 > 8);
 
-- 
2.20.1