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-rw-r--r--fs/btrfs/backref.c14
-rw-r--r--fs/btrfs/backref.h3
-rw-r--r--fs/btrfs/ctree.c21
-rw-r--r--fs/btrfs/ctree.h3
-rw-r--r--fs/btrfs/relocation.c7
5 files changed, 33 insertions, 15 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index b7d54efb4728..a4a809efc92f 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -3196,12 +3196,14 @@ static int handle_direct_tree_backref(struct btrfs_backref_cache *cache,
* We still need to do a tree search to find out the parents. This is for
* TREE_BLOCK_REF backref (keyed or inlined).
*
+ * @trans: Transaction handle.
* @ref_key: The same as @ref_key in handle_direct_tree_backref()
* @tree_key: The first key of this tree block.
* @path: A clean (released) path, to avoid allocating path every time
* the function get called.
*/
-static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache,
+static int handle_indirect_tree_backref(struct btrfs_trans_handle *trans,
+ struct btrfs_backref_cache *cache,
struct btrfs_path *path,
struct btrfs_key *ref_key,
struct btrfs_key *tree_key,
@@ -3315,7 +3317,7 @@ static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache,
* If we know the block isn't shared we can avoid
* checking its backrefs.
*/
- if (btrfs_block_can_be_shared(root, eb))
+ if (btrfs_block_can_be_shared(trans, root, eb))
upper->checked = 0;
else
upper->checked = 1;
@@ -3363,11 +3365,13 @@ out:
* links aren't yet bi-directional. Needs to finish such links.
* Use btrfs_backref_finish_upper_links() to finish such linkage.
*
+ * @trans: Transaction handle.
* @path: Released path for indirect tree backref lookup
* @iter: Released backref iter for extent tree search
* @node_key: The first key of the tree block
*/
-int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
+int btrfs_backref_add_tree_node(struct btrfs_trans_handle *trans,
+ struct btrfs_backref_cache *cache,
struct btrfs_path *path,
struct btrfs_backref_iter *iter,
struct btrfs_key *node_key,
@@ -3467,8 +3471,8 @@ int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
* offset means the root objectid. We need to search
* the tree to get its parent bytenr.
*/
- ret = handle_indirect_tree_backref(cache, path, &key, node_key,
- cur);
+ ret = handle_indirect_tree_backref(trans, cache, path,
+ &key, node_key, cur);
if (ret < 0)
goto out;
}
diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index 1616e3e3f1e4..71d535e03dca 100644
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -540,7 +540,8 @@ static inline void btrfs_backref_panic(struct btrfs_fs_info *fs_info,
bytenr);
}
-int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
+int btrfs_backref_add_tree_node(struct btrfs_trans_handle *trans,
+ struct btrfs_backref_cache *cache,
struct btrfs_path *path,
struct btrfs_backref_iter *iter,
struct btrfs_key *node_key,
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index da519c1b6ad0..617d4827eec2 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -367,7 +367,8 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
/*
* check if the tree block can be shared by multiple trees
*/
-int btrfs_block_can_be_shared(struct btrfs_root *root,
+int btrfs_block_can_be_shared(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
struct extent_buffer *buf)
{
/*
@@ -376,11 +377,21 @@ int btrfs_block_can_be_shared(struct btrfs_root *root,
* not allocated by tree relocation, we know the block is not shared.
*/
if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
- buf != root->node && buf != root->commit_root &&
+ buf != root->node &&
(btrfs_header_generation(buf) <=
btrfs_root_last_snapshot(&root->root_item) ||
- btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
- return 1;
+ btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) {
+ if (buf != root->commit_root)
+ return 1;
+ /*
+ * An extent buffer that used to be the commit root may still be
+ * shared because the tree height may have increased and it
+ * became a child of a higher level root. This can happen when
+ * snapshotting a subvolume created in the current transaction.
+ */
+ if (btrfs_header_generation(buf) == trans->transid)
+ return 1;
+ }
return 0;
}
@@ -415,7 +426,7 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
* are only allowed for blocks use full backrefs.
*/
- if (btrfs_block_can_be_shared(root, buf)) {
+ if (btrfs_block_can_be_shared(trans, root, buf)) {
ret = btrfs_lookup_extent_info(trans, fs_info, buf->start,
btrfs_header_level(buf), 1,
&refs, &flags);
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9419f4e37a58..ff40acd63a37 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -540,7 +540,8 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
struct extent_buffer **cow_ret, u64 new_root_objectid);
-int btrfs_block_can_be_shared(struct btrfs_root *root,
+int btrfs_block_can_be_shared(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
struct extent_buffer *buf);
int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, int level, int slot);
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 9951a0caf5bb..c6d4bb8cbe29 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -466,6 +466,7 @@ static bool handle_useless_nodes(struct reloc_control *rc,
* cached.
*/
static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
+ struct btrfs_trans_handle *trans,
struct reloc_control *rc, struct btrfs_key *node_key,
int level, u64 bytenr)
{
@@ -499,8 +500,8 @@ static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
/* Breadth-first search to build backref cache */
do {
- ret = btrfs_backref_add_tree_node(cache, path, iter, node_key,
- cur);
+ ret = btrfs_backref_add_tree_node(trans, cache, path, iter,
+ node_key, cur);
if (ret < 0) {
err = ret;
goto out;
@@ -2803,7 +2804,7 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans,
/* Do tree relocation */
rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
- node = build_backref_tree(rc, &block->key,
+ node = build_backref_tree(trans, rc, &block->key,
block->level, block->bytenr);
if (IS_ERR(node)) {
err = PTR_ERR(node);