[PATCH v2 3/3] btrfs: fix sparse lock context warnings

[Omar Sandoval <osandov@osandov.com>]

Fix several sparse warnings that can easily be addressed with context
annotations. These annotations also provide some sort of documentation for the
internal helper functions.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
---
 fs/btrfs/extent-tree.c      | 1 +
 fs/btrfs/extent_io.c        | 2 +-
 fs/btrfs/free-space-cache.c | 1 +
 fs/btrfs/locking.c          | 1 +
 4 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 3efe1c3..281f30f 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6387,6 +6387,7 @@ static struct btrfs_block_group_cache *
 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
 		   struct btrfs_free_cluster *cluster,
 		   int delalloc)
+__acquires(&cluster->refill_lock)
 {
 	struct btrfs_block_group_cache *used_bg;
 	bool locked = false;
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index af0359d..cc6b1fc 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4775,8 +4775,8 @@ static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
 	__free_extent_buffer(eb);
 }
 
-/* Expects to have eb->eb_lock already held */
 static int release_extent_buffer(struct extent_buffer *eb)
+__releases(&eb->refs_lock)
 {
 	WARN_ON(atomic_read(&eb->refs) == 0);
 	if (atomic_dec_and_test(&eb->refs)) {
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 2b0a627..41c6cd5 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1838,6 +1838,7 @@ static struct btrfs_free_space_op free_space_op = {
 
 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
 			      struct btrfs_free_space *info)
+__must_hold(&ctl->tree_lock)
 {
 	struct btrfs_free_space *bitmap_info;
 	struct btrfs_block_group_cache *block_group = NULL;
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 5665d21..47bdc2c 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -222,6 +222,7 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb)
  * blocking readers or writers
  */
 void btrfs_tree_lock(struct extent_buffer *eb)
+__acquires(&eb->lock)
 {
 again:
 	wait_event(eb->read_lock_wq, atomic_read(&eb->blocking_readers) == 0);
-- 
2.1.1