From dde5abee12327d59f968bbfc8151e1b04082a2c4 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Thu, 16 Sep 2010 16:17:03 -0400 Subject: Btrfs: check cache->caching_ctl before returning if caching has started With the free space disk caching we can mark the block group as started with the caching, but we don't have a caching ctl. This can race with anybody else who tries to get the caching ctl before we cache (this is very hard to do btw). So instead check to see if cache->caching_ctl is set, and if not return NULL. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/extent-tree.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 9a325e465ad9..5c9ef3ac25e1 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -242,6 +242,12 @@ get_caching_control(struct btrfs_block_group_cache *cache) return NULL; } + /* We're loading it the fast way, so we don't have a caching_ctl. */ + if (!cache->caching_ctl) { + spin_unlock(&cache->lock); + return NULL; + } + ctl = cache->caching_ctl; atomic_inc(&ctl->count); spin_unlock(&cache->lock); -- cgit