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authorJoe Thornber <ejt@redhat.com>2014-03-03 15:46:42 +0000
committerMike Snitzer <snitzer@redhat.com>2014-03-05 15:26:58 -0500
commit18adc57779866ba451237dccca2ebf019be2fa20 (patch)
treea0f3a9d473fd433b7ffd5a7160ee55ad6d2ffd62
parent3e1a0699095803e53072699a4a1485af7744601d (diff)
downloadlinux-18adc57779866ba451237dccca2ebf019be2fa20.tar.gz
dm thin: fix deadlock in __requeue_bio_list
The spin lock in requeue_io() was held for too long, allowing deadlock. Don't worry, due to other issues addressed in the following "dm thin: fix noflush suspend IO queueing" commit, this code was never called. Fix this by taking the spin lock for a much shorter period of time. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
-rw-r--r--drivers/md/dm-thin.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 38a063f7afa4..f39876dd307d 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -369,14 +369,18 @@ struct dm_thin_endio_hook {
struct dm_thin_new_mapping *overwrite_mapping;
};
-static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
+static void requeue_bio_list(struct thin_c *tc, struct bio_list *master)
{
struct bio *bio;
struct bio_list bios;
+ unsigned long flags;
bio_list_init(&bios);
+
+ spin_lock_irqsave(&tc->pool->lock, flags);
bio_list_merge(&bios, master);
bio_list_init(master);
+ spin_unlock_irqrestore(&tc->pool->lock, flags);
while ((bio = bio_list_pop(&bios))) {
struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
@@ -391,12 +395,9 @@ static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
static void requeue_io(struct thin_c *tc)
{
struct pool *pool = tc->pool;
- unsigned long flags;
- spin_lock_irqsave(&pool->lock, flags);
- __requeue_bio_list(tc, &pool->deferred_bios);
- __requeue_bio_list(tc, &pool->retry_on_resume_list);
- spin_unlock_irqrestore(&pool->lock, flags);
+ requeue_bio_list(tc, &pool->deferred_bios);
+ requeue_bio_list(tc, &pool->retry_on_resume_list);
}
static void error_retry_list(struct pool *pool)