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. Thanks,
Signed-off-by: Josef Bacik <[email protected]> --- fs/btrfs/extent_io.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 7926e1e..b778fc2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -4319,7 +4319,7 @@ 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)) { @@ -4340,9 +4340,11 @@ 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; + return 1; } spin_unlock(&eb->refs_lock); + + return 0; } void free_extent_buffer(struct extent_buffer *eb) @@ -4981,7 +4983,6 @@ int try_release_extent_buffer(struct page *page, gfp_t mask) spin_unlock(&eb->refs_lock); return 0; } - release_extent_buffer(eb, mask); - return 1; + return release_extent_buffer(eb, mask); } -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
