diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-05-23 11:14:10 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-05-23 11:14:10 -0700 |
| commit | 7ce14f6ff26460819345fe8495cf2dd6538b7cdc (patch) | |
| tree | 23fb69457c5f2c3b80aebf2a7351b57d87426c6d /fs/btrfs/backref.c | |
| parent | cf539cbd8a81e12880735a0912de8b99f46c84fd (diff) | |
| parent | 153c35b6cccc0c72de9fae06c8e2c8b2c47d79d4 (diff) | |
Merge branch 'for-linus-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
"I fixed up a regression from 4.0 where conversion between different
raid levels would sometimes bail out without converting.
Filipe tracked down a race where it was possible to double allocate
chunks on the drive.
Mark has a fix for fiemap. All three will get bundled off for stable
as well"
* 'for-linus-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: fix regression in raid level conversion
Btrfs: fix racy system chunk allocation when setting block group ro
btrfs: clear 'ret' in btrfs_check_shared() loop
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; |