btrfs: handle ENOMEM in btrfs_alloc_tree_block
This is one of the first places to give out when memory is tight. Handle
it properly rather than with a BUG_ON.
Also fix the comment about the return value, which is an ERR_PTR, not
NULL, on error.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 6f420c8..0ec8e22 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7546,7 +7546,7 @@
* returns the key for the extent through ins, and a tree buffer for
* the first block of the extent through buf.
*
- * returns the tree buffer or NULL.
+ * returns the tree buffer or an ERR_PTR on error.
*/
struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
@@ -7557,6 +7557,7 @@
struct btrfs_key ins;
struct btrfs_block_rsv *block_rsv;
struct extent_buffer *buf;
+ struct btrfs_delayed_extent_op *extent_op;
u64 flags = 0;
int ret;
u32 blocksize = root->nodesize;
@@ -7577,13 +7578,14 @@
ret = btrfs_reserve_extent(root, blocksize, blocksize,
empty_size, hint, &ins, 0, 0);
- if (ret) {
- unuse_block_rsv(root->fs_info, block_rsv, blocksize);
- return ERR_PTR(ret);
- }
+ if (ret)
+ goto out_unuse;
buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
- BUG_ON(IS_ERR(buf)); /* -ENOMEM */
+ if (IS_ERR(buf)) {
+ ret = PTR_ERR(buf);
+ goto out_free_reserved;
+ }
if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
if (parent == 0)
@@ -7593,9 +7595,11 @@
BUG_ON(parent > 0);
if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
- struct btrfs_delayed_extent_op *extent_op;
extent_op = btrfs_alloc_delayed_extent_op();
- BUG_ON(!extent_op); /* -ENOMEM */
+ if (!extent_op) {
+ ret = -ENOMEM;
+ goto out_free_buf;
+ }
if (key)
memcpy(&extent_op->key, key, sizeof(extent_op->key));
else
@@ -7610,13 +7614,24 @@
extent_op->level = level;
ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
- ins.objectid,
- ins.offset, parent, root_objectid,
- level, BTRFS_ADD_DELAYED_EXTENT,
- extent_op, 0);
- BUG_ON(ret); /* -ENOMEM */
+ ins.objectid, ins.offset,
+ parent, root_objectid, level,
+ BTRFS_ADD_DELAYED_EXTENT,
+ extent_op, 0);
+ if (ret)
+ goto out_free_delayed;
}
return buf;
+
+out_free_delayed:
+ btrfs_free_delayed_extent_op(extent_op);
+out_free_buf:
+ free_extent_buffer(buf);
+out_free_reserved:
+ btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
+out_unuse:
+ unuse_block_rsv(root->fs_info, block_rsv, blocksize);
+ return ERR_PTR(ret);
}
struct walk_control {