It's good to have a helper instead of having all get-root details
open-coded.
The new helper locks (if necessary) and sets root node of the path.
There is no functional change in this commit.
Signed-off-by: Liu Bo <bo....@linux.alibaba.com>
---
fs/btrfs/ctree.c | 112 +++++++++++++++++++++++++++++++++----------------------
1 file changed, 67 insertions(+), 45 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index a96d308c51b8..399839df7a8f 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2598,6 +2598,72 @@ int btrfs_find_item(struct btrfs_root *fs_root, struct
btrfs_path *path,
return 0;
}
+static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root
*root,
+ struct btrfs_path *p,
+ int write_lock_level)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct extent_buffer *b;
+ int root_lock;
+ int level = 0;
+
+ /*
+ * we try very hard to do read locks on the root
+ */
+ root_lock = BTRFS_READ_LOCK;
+
+ if (p->search_commit_root) {
+ /*
+ * the commit roots are read only so we always do read locks
+ */
+ if (p->need_commit_sem)
+ down_read(&fs_info->commit_root_sem);
+ b = root->commit_root;
+ extent_buffer_get(b);
+ level = btrfs_header_level(b);
+ if (p->need_commit_sem)
+ up_read(&fs_info->commit_root_sem);
+ if (!p->skip_locking)
+ btrfs_tree_read_lock(b);
+
+ goto out;
+ }
+
+ if (p->skip_locking) {
+ b = btrfs_root_node(root);
+ level = btrfs_header_level(b);
+ goto out;
+ }
+
+ /*
+ * we don't know the level of the root node until we actually
+ * have it read locked
+ */
+ b = btrfs_read_lock_root_node(root);
+ level = btrfs_header_level(b);
+ if (level > write_lock_level)
+ goto out;
+
+ /*
+ * whoops, must trade for write lock
+ */
+ btrfs_tree_read_unlock(b);
+ free_extent_buffer(b);
+ b = btrfs_lock_root_node(root);
+ root_lock = BTRFS_WRITE_LOCK;
+ /*
+ * the level might have changed, check again
+ */
+ level = btrfs_header_level(b);
+
+out:
+ p->nodes[level] = b;
+ if (!p->skip_locking)
+ p->locks[level] = root_lock;
+ return b;
+}
+
+
/*
* btrfs_search_slot - look for a key in a tree and perform necessary
* modifications to preserve tree invariants.
@@ -2634,7 +2700,6 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
int err;
int level;
int lowest_unlock = 1;
- int root_lock;
/* everything at write_lock_level or lower must be write locked */
int write_lock_level = 0;
u8 lowest_level = 0;
@@ -2672,50 +2737,7 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
again:
prev_cmp = -1;
- /*
- * we try very hard to do read locks on the root
- */
- root_lock = BTRFS_READ_LOCK;
- level = 0;
- if (p->search_commit_root) {
- /*
- * the commit roots are read only
- * so we always do read locks
- */
- if (p->need_commit_sem)
- down_read(&fs_info->commit_root_sem);
- b = root->commit_root;
- extent_buffer_get(b);
- level = btrfs_header_level(b);
- if (p->need_commit_sem)
- up_read(&fs_info->commit_root_sem);
- if (!p->skip_locking)
- btrfs_tree_read_lock(b);
- } else {
- if (p->skip_locking) {
- b = btrfs_root_node(root);
- level = btrfs_header_level(b);
- } else {
- /* we don't know the level of the root node
- * until we actually have it read locked
- */
- b = btrfs_read_lock_root_node(root);
- level = btrfs_header_level(b);
- if (level <= write_lock_level) {
- /* whoops, must trade for write lock */
- btrfs_tree_read_unlock(b);
- free_extent_buffer(b);
- b = btrfs_lock_root_node(root);
- root_lock = BTRFS_WRITE_LOCK;
-
- /* the level might have changed, check again */
- level = btrfs_header_level(b);
- }
- }
- }
- p->nodes[level] = b;
- if (!p->skip_locking)
- p->locks[level] = root_lock;
+ b = btrfs_search_slot_get_root(root, p, write_lock_level);
while (b) {
level = btrfs_header_level(b);
--
1.8.3.1
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