[PATCH 09/43] btrfs: handle NULL roots in btrfs_put/btrfs_grab_fs_root

Josef Bacik
2020-01-17T21:26:26Z

We want to use this for dropping all roots, and in some error cases we
may not have a root, so handle this to make the cleanup code easier.
Make btrfs_grab_fs_root the same so we can use it in cases where the
root may not exist (like the quota root).

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/disk-io.h | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 7aa1c7a3a115..8add2e14aab1 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -88,6 +88,8 @@ struct btrfs_root *btrfs_alloc_dummy_root(struct btrfs_fs_info *fs_info);
*/
static inline struct btrfs_root *btrfs_grab_fs_root(struct btrfs_root *root)
{
+ if (!root)
+ return NULL;
if (refcount_inc_not_zero(&root->refs))
return root;
return NULL;
@@ -95,6 +97,8 @@ static inline struct btrfs_root *btrfs_grab_fs_root(struct btrfs_root *root)

static inline void btrfs_put_fs_root(struct btrfs_root *root)
{
+ if (!root)
+ return;
if (refcount_dec_and_test(&root->refs))
kfree(root);
}
--
2.24.1