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| author | Ingo Molnar <mingo@kernel.org> | 2015-06-02 09:05:42 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-06-02 09:05:42 +0300 |
| commit | f407a8258610169cd8e975dba7f0b2824562014c (patch) | |
| tree | 6c87b2d168a4665411a9e16b9f481599f2db25bc /fs/btrfs/backref.c | |
| parent | 960d447b94b22ceba286917056871d1dac8da697 (diff) | |
| parent | c46a024ea5eb0165114dbbc8c82c29b7bcf66e71 (diff) | |
| download | linux-f407a8258610169cd8e975dba7f0b2824562014c.tar.xz | |
Merge branch 'linus' into sched/core, to resolve conflict
Conflicts:
arch/sparc/include/asm/topology_64.h
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'fs/btrfs/backref.c')
| -rw-r--r-- | fs/btrfs/backref.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 9de772ee0031..614aaa1969bd 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -880,6 +880,8 @@ static int __add_keyed_refs(struct btrfs_fs_info *fs_info, * indirect refs to their parent bytenr. * When roots are found, they're added to the roots list * + * NOTE: This can return values > 0 + * * FIXME some caching might speed things up */ static int find_parent_nodes(struct btrfs_trans_handle *trans, @@ -1198,6 +1200,19 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans, return ret; } +/** + * btrfs_check_shared - tell us whether an extent is shared + * + * @trans: optional trans handle + * + * btrfs_check_shared uses the backref walking code but will short + * circuit as soon as it finds a root or inode that doesn't match the + * one passed in. This provides a significant performance benefit for + * callers (such as fiemap) which want to know whether the extent is + * shared but do not need a ref count. + * + * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error. + */ int btrfs_check_shared(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, u64 root_objectid, u64 inum, u64 bytenr) @@ -1226,11 +1241,13 @@ int btrfs_check_shared(struct btrfs_trans_handle *trans, ret = find_parent_nodes(trans, fs_info, bytenr, elem.seq, tmp, roots, NULL, root_objectid, inum); if (ret == BACKREF_FOUND_SHARED) { + /* this is the only condition under which we return 1 */ ret = 1; break; } if (ret < 0 && ret != -ENOENT) break; + ret = 0; node = ulist_next(tmp, &uiter); if (!node) break; |