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authorJosef Bacik <jbacik@fb.com>2014-09-11 00:20:45 +0400
committerChris Mason <clm@fb.com>2014-09-18 00:38:24 +0400
commitdc046b10c8b7d4f40befe457acb82340bf8b0699 (patch)
tree2659e92649b19df4cd54a65eabd34f961f8d57f8 /fs/btrfs/backref.h
parent78a017a2c92df9b571db0a55a016280f9019c65e (diff)
downloadlinux-dc046b10c8b7d4f40befe457acb82340bf8b0699.tar.xz
Btrfs: make fiemap not blow when you have lots of snapshots
We have been iterating all references for each extent we have in a file when we do fiemap to see if it is shared. This is fine when you have a few clones or a few snapshots, but when you have 5k snapshots suddenly fiemap just sits there and stares at you. So add btrfs_check_shared which will use the backref walking code but will short circuit as soon as it finds a root or inode that doesn't match the one we currently have. This makes fiemap on my testbox go from looking at me blankly for a day to spitting out actual output in a reasonable amount of time. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs/backref.h')
-rw-r--r--fs/btrfs/backref.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index 86fc20fec282..2a1ac6bfc724 100644
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -71,6 +71,9 @@ int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
u64 start_off, struct btrfs_path *path,
struct btrfs_inode_extref **ret_extref,
u64 *found_off);
+int btrfs_check_shared(struct btrfs_trans_handle *trans,
+ struct btrfs_fs_info *fs_info, u64 root_objectid,
+ u64 inum, u64 bytenr);
int __init btrfs_prelim_ref_init(void);
void btrfs_prelim_ref_exit(void);