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| author | Nikolay Borisov <nborisov@suse.com> | 2018-08-15 18:26:52 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-12-17 14:51:30 +0100 |
| commit | 5c623d334a4f7f270de223cde2a3f3b743023e2a (patch) | |
| tree | 6392b12ed09d4bb8a11955cb270cae551d7cec3c | |
| parent | e5bba0b0f843e047ca025b53f1dcfa7e6bd05d86 (diff) | |
| download | linux-5c623d334a4f7f270de223cde2a3f3b743023e2a.tar.gz | |
btrfs: Remove needless tree locking in iterate_inode_extrefs
In iterate_inode_exrefs the eb is cloned via btrfs_clone_extent_buffer which creates a private extent buffer with the dummy flag set and ref count of 1. Then this buffer is locked for reading and its ref count is incremented by 1. Finally it's fed to the passed iterate_irefs_t function. The actual iterate call back is inode_to_path (coming from paths_from_inode) which feeds the eb to btrfs_ref_to_path. In this final function the passed eb is only read by first assigning it to the local eb variable. This variable is only modified in the case another eb was referenced from the passed path that is eb != eb_in check triggers. Considering this there is no point in locking the cloned eb in iterate_inode_refs since it's never being modified and is not published anywhere. Furthermore the cloned eb is completely fine having its ref count be 1. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/backref.c | 5 |
1 files changed, 0 insertions, 5 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 65f327b34cfb..4a15f87dbbb4 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -2079,10 +2079,6 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, ret = -ENOMEM; break; } - extent_buffer_get(eb); - - btrfs_tree_read_lock(eb); - btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); btrfs_release_path(path); item_size = btrfs_item_size_nr(eb, slot); @@ -2103,7 +2099,6 @@ static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, cur_offset += btrfs_inode_extref_name_len(eb, extref); cur_offset += sizeof(*extref); } - btrfs_tree_read_unlock_blocking(eb); free_extent_buffer(eb); offset++; |