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-rw-r--r--fs/btrfs/extent-tree.c23
1 files changed, 22 insertions, 1 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 78ad31a59e59..36a3c973fda1 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3323,6 +3323,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
if (last_ref && btrfs_header_generation(buf) == trans->transid) {
struct btrfs_block_group *cache;
+ bool must_pin = false;
if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
ret = check_ref_cleanup(trans, buf->start);
@@ -3340,7 +3341,27 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
goto out;
}
- if (btrfs_is_zoned(fs_info)) {
+ /*
+ * If this is a leaf and there are tree mod log users, we may
+ * have recorded mod log operations that point to this leaf.
+ * So we must make sure no one reuses this leaf's extent before
+ * mod log operations are applied to a node, otherwise after
+ * rewinding a node using the mod log operations we get an
+ * inconsistent btree, as the leaf's extent may now be used as
+ * a node or leaf for another different btree.
+ * We are safe from races here because at this point no other
+ * node or root points to this extent buffer, so if after this
+ * check a new tree mod log user joins, it will not be able to
+ * find a node pointing to this leaf and record operations that
+ * point to this leaf.
+ */
+ if (btrfs_header_level(buf) == 0) {
+ read_lock(&fs_info->tree_mod_log_lock);
+ must_pin = !list_empty(&fs_info->tree_mod_seq_list);
+ read_unlock(&fs_info->tree_mod_log_lock);
+ }
+
+ if (must_pin || btrfs_is_zoned(fs_info)) {
btrfs_redirty_list_add(trans->transaction, buf);
pin_down_extent(trans, cache, buf->start, buf->len, 1);
btrfs_put_block_group(cache);