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Diffstat (limited to 'fs/btrfs/backref.c')
-rw-r--r--fs/btrfs/backref.c76
1 files changed, 58 insertions, 18 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 9de772ee0031..802fabb30e15 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -250,8 +250,12 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
* the first item to check. But sometimes, we may enter it with
* slot==nritems. In that case, go to the next leaf before we continue.
*/
- if (path->slots[0] >= btrfs_header_nritems(path->nodes[0]))
- ret = btrfs_next_old_leaf(root, path, time_seq);
+ if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
+ if (time_seq == (u64)-1)
+ ret = btrfs_next_leaf(root, path);
+ else
+ ret = btrfs_next_old_leaf(root, path, time_seq);
+ }
while (!ret && count < total_refs) {
eb = path->nodes[0];
@@ -291,7 +295,10 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
eie = NULL;
}
next:
- ret = btrfs_next_old_item(root, path, time_seq);
+ if (time_seq == (u64)-1)
+ ret = btrfs_next_item(root, path);
+ else
+ ret = btrfs_next_old_item(root, path, time_seq);
}
if (ret > 0)
@@ -334,6 +341,8 @@ static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
if (path->search_commit_root)
root_level = btrfs_header_level(root->commit_root);
+ else if (time_seq == (u64)-1)
+ root_level = btrfs_header_level(root->node);
else
root_level = btrfs_old_root_level(root, time_seq);
@@ -343,7 +352,12 @@ static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
}
path->lowest_level = level;
- ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq);
+ if (time_seq == (u64)-1)
+ ret = btrfs_search_slot(NULL, root, &ref->key_for_search, path,
+ 0, 0);
+ else
+ ret = btrfs_search_old_slot(root, &ref->key_for_search, path,
+ time_seq);
/* root node has been locked, we can release @subvol_srcu safely here */
srcu_read_unlock(&fs_info->subvol_srcu, index);
@@ -491,7 +505,9 @@ static int __add_missing_keys(struct btrfs_fs_info *fs_info,
BUG_ON(!ref->wanted_disk_byte);
eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
0);
- if (!eb || !extent_buffer_uptodate(eb)) {
+ if (IS_ERR(eb)) {
+ return PTR_ERR(eb);
+ } else if (!extent_buffer_uptodate(eb)) {
free_extent_buffer(eb);
return -EIO;
}
@@ -507,7 +523,7 @@ static int __add_missing_keys(struct btrfs_fs_info *fs_info,
}
/*
- * merge two lists of backrefs and adjust counts accordingly
+ * merge backrefs and adjust counts accordingly
*
* mode = 1: merge identical keys, if key is set
* FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
@@ -535,9 +551,9 @@ static void __merge_refs(struct list_head *head, int mode)
ref2 = list_entry(pos2, struct __prelim_ref, list);
+ if (!ref_for_same_block(ref1, ref2))
+ continue;
if (mode == 1) {
- if (!ref_for_same_block(ref1, ref2))
- continue;
if (!ref1->parent && ref2->parent) {
xchg = ref1;
ref1 = ref2;
@@ -572,8 +588,8 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
struct list_head *prefs, u64 *total_refs,
u64 inum)
{
+ struct btrfs_delayed_ref_node *node;
struct btrfs_delayed_extent_op *extent_op = head->extent_op;
- struct rb_node *n = &head->node.rb_node;
struct btrfs_key key;
struct btrfs_key op_key = {0};
int sgn;
@@ -583,12 +599,7 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
spin_lock(&head->lock);
- n = rb_first(&head->ref_root);
- while (n) {
- struct btrfs_delayed_ref_node *node;
- node = rb_entry(n, struct btrfs_delayed_ref_node,
- rb_node);
- n = rb_next(n);
+ list_for_each_entry(node, &head->ref_list, list) {
if (node->seq > seq)
continue;
@@ -880,6 +891,13 @@ 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
+ *
+ * If time_seq is set to (u64)-1, it will not search delayed_refs, and behave
+ * much like trans == NULL case, the difference only lies in it will not
+ * commit root.
+ * The special case is for qgroup to search roots in commit_transaction().
+ *
* FIXME some caching might speed things up
*/
static int find_parent_nodes(struct btrfs_trans_handle *trans,
@@ -918,6 +936,9 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
path->skip_locking = 1;
}
+ if (time_seq == (u64)-1)
+ path->skip_locking = 1;
+
/*
* grab both a lock on the path and a lock on the delayed ref head.
* We need both to get a consistent picture of how the refs look
@@ -932,9 +953,10 @@ again:
BUG_ON(ret == 0);
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
- if (trans && likely(trans->type != __TRANS_DUMMY)) {
+ if (trans && likely(trans->type != __TRANS_DUMMY) &&
+ time_seq != (u64)-1) {
#else
- if (trans) {
+ if (trans && time_seq != (u64)-1) {
#endif
/*
* look if there are updates for this ref queued and lock the
@@ -1032,7 +1054,10 @@ again:
eb = read_tree_block(fs_info->extent_root,
ref->parent, 0);
- if (!eb || !extent_buffer_uptodate(eb)) {
+ if (IS_ERR(eb)) {
+ ret = PTR_ERR(eb);
+ goto out;
+ } else if (!extent_buffer_uptodate(eb)) {
free_extent_buffer(eb);
ret = -EIO;
goto out;
@@ -1198,6 +1223,19 @@ 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 +1264,13 @@ 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;
generated by cgit (git 2.34.1) at 2024-05-28 03:47:04 +0000