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Commit 67b7859e authored by Omar Sandoval's avatar Omar Sandoval Committed by Chris Mason
Browse files

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: default avatarOmar Sandoval <osandov@osandov.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.cz>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 1b984508

fs/btrfs/extent-tree.c

+28 −13
Original line number Original line Diff line number Diff line
@@ -7546,7 +7546,7 @@ static void unuse_block_rsv(struct btrfs_fs_info *fs_info, 
 * returns the key for the extent through ins, and a tree buffer for

 * returns the key for the extent through ins, and a tree buffer for

 * the first block of the extent through buf.

 * 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 extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,

					struct btrfs_root *root,

					struct btrfs_root *root,
@@ -7557,6 +7557,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, 
	struct btrfs_key ins;

	struct btrfs_key ins;

	struct btrfs_block_rsv *block_rsv;

	struct btrfs_block_rsv *block_rsv;

	struct extent_buffer *buf;

	struct extent_buffer *buf;

	struct btrfs_delayed_extent_op *extent_op;

	u64 flags = 0;

	u64 flags = 0;

	int ret;

	int ret;

	u32 blocksize = root->nodesize;

	u32 blocksize = root->nodesize;
@@ -7577,13 +7578,14 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, 




	ret = btrfs_reserve_extent(root, blocksize, blocksize,

	ret = btrfs_reserve_extent(root, blocksize, blocksize,

				   empty_size, hint, &ins, 0, 0);

				   empty_size, hint, &ins, 0, 0);

	if (ret) {

	if (ret)

		unuse_block_rsv(root->fs_info, block_rsv, blocksize);

		goto out_unuse;

		return ERR_PTR(ret);

	}





	buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);

	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 (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {

		if (parent == 0)

		if (parent == 0)
@@ -7593,9 +7595,11 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, 
		BUG_ON(parent > 0);

		BUG_ON(parent > 0);





	if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {

	if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {

		struct btrfs_delayed_extent_op *extent_op;

		extent_op = btrfs_alloc_delayed_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)

		if (key)

			memcpy(&extent_op->key, key, sizeof(extent_op->key));

			memcpy(&extent_op->key, key, sizeof(extent_op->key));

		else

		else
@@ -7610,13 +7614,24 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, 
		extent_op->level = level;

		extent_op->level = level;





		ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,

		ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,

					ins.objectid,

						 ins.objectid, ins.offset,

					ins.offset, parent, root_objectid,

						 parent, root_objectid, level,

					level, BTRFS_ADD_DELAYED_EXTENT,

						 BTRFS_ADD_DELAYED_EXTENT,

						 extent_op, 0);

						 extent_op, 0);

		BUG_ON(ret); /* -ENOMEM */

		if (ret)

			goto out_free_delayed;

	}

	}

	return buf;

	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 {

struct walk_control {