btrfs: fiemap: preallocate ulists for btrfs_check_shared
btrfs_check_shared looks up parents of a given extent and uses ulists
for that. These are allocated and freed repeatedly. Preallocation in the
caller will avoid the overhead and also allow us to use the GFP_KERNEL
as it is happens before the extent locks are taken.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 982152d..89116afd 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1465,12 +1465,11 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
*
* Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
*/
-int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr)
+int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
+ struct ulist *roots, struct ulist *tmp)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_trans_handle *trans;
- struct ulist *tmp = NULL;
- struct ulist *roots = NULL;
struct ulist_iterator uiter;
struct ulist_node *node;
struct seq_list elem = SEQ_LIST_INIT(elem);
@@ -1481,12 +1480,8 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr)
.share_count = 0,
};
- tmp = ulist_alloc(GFP_NOFS);
- roots = ulist_alloc(GFP_NOFS);
- if (!tmp || !roots) {
- ret = -ENOMEM;
- goto out;
- }
+ ulist_init(roots);
+ ulist_init(tmp);
trans = btrfs_attach_transaction(root);
if (IS_ERR(trans)) {
@@ -1527,8 +1522,8 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr)
up_read(&fs_info->commit_root_sem);
}
out:
- ulist_free(tmp);
- ulist_free(roots);
+ ulist_release(roots);
+ ulist_release(tmp);
return ret;
}