Commit e64860aa authored by Josef Bacik's avatar Josef Bacik Committed by Chris Mason
Browse files

Btrfs: don't return true in releasepage unless we actually freed the eb

I noticed while looking at an extent_buffer race that we will
unconditionally return 1 if we get down to release_extent_buffer after
clearing the tree ref.  However we can easily race in here and get a ref on
the eb and not actually free the eb.  So make release_extent_buffer return 1
if it free'd the eb and 0 if not so we can be a little kinder to the vm.
Signed-off-by: default avatarJosef Bacik <>
parent a98cdb85
......@@ -4300,7 +4300,7 @@ static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
/* Expects to have eb->eb_lock already held */
static void release_extent_buffer(struct extent_buffer *eb, gfp_t mask)
static int release_extent_buffer(struct extent_buffer *eb, gfp_t mask)
WARN_ON(atomic_read(&eb->refs) == 0);
if (atomic_dec_and_test(&eb->refs)) {
......@@ -4321,9 +4321,11 @@ static void release_extent_buffer(struct extent_buffer *eb, gfp_t mask)
btrfs_release_extent_buffer_page(eb, 0);
call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
return 1;
return 0;
void free_extent_buffer(struct extent_buffer *eb)
......@@ -4962,7 +4964,6 @@ int try_release_extent_buffer(struct page *page, gfp_t mask)
return 0;
release_extent_buffer(eb, mask);
return 1;
return release_extent_buffer(eb, mask);
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment