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btrfs: backref: Add special time_seq == (u64)-1 case for 

btrfs_find_all_roots().

Allow btrfs_find_all_roots() to skip all delayed_ref_head lock and tree
lock to do tree search.

This is important for later qgroup implement which will call
find_all_roots() after fs trees are committed.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
steinar/wifi_calib_4_9_kernel
Qu Wenruo 2015-04-16 14:54:50 +08:00 committed by Chris Mason
parent 3b7d00f99c
commit 21633fc603
1 changed files with 29 additions and 6 deletions
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35
fs/btrfs/backref.c
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@ -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);
@ -879,6 +893,11 @@ static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
*
* 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,
@ -917,6 +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
@ -931,9 +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