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Commit 5662344b authored by Tsutomu Itoh's avatar Tsutomu Itoh Committed by Chris Mason
Browse files

Btrfs: fix error check of btrfs_lookup_dentry() 



Clean up btrfs_lookup_dentry() to never return NULL, but PTR_ERR(-ENOENT)
instead. This keeps the return value convention consistent.

Callers who use btrfs_lookup_dentry() require a trivial update.

create_snapshot() in particular looks like it can also lose a BUG_ON(!inode)
which is not really needed - there seems less harm in returning ENOENT to
userspace at that point in the stack than there is to crash the machine.

Signed-off-by: default avatarTsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 78357766

fs/btrfs/inode.c

+11 −4
Original line number Diff line number Diff line
@@ -4992,7 +4992,7 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry) 
		return ERR_PTR(ret);



	if (location.objectid == 0)

		return NULL;

		return ERR_PTR(-ENOENT);



	if (location.type == BTRFS_INODE_ITEM_KEY) {

		inode = btrfs_iget(dir->i_sb, &location, root, NULL);
@@ -5056,10 +5056,17 @@ static void btrfs_dentry_release(struct dentry *dentry) 
static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,

				   unsigned int flags)

{

	struct dentry *ret;

	struct inode *inode;



	ret = d_splice_alias(btrfs_lookup_dentry(dir, dentry), dentry);

	return ret;

	inode = btrfs_lookup_dentry(dir, dentry);

	if (IS_ERR(inode)) {

		if (PTR_ERR(inode) == -ENOENT)

			inode = NULL;

		else

			return ERR_CAST(inode);

	}



	return d_splice_alias(inode, dentry);

}



unsigned char btrfs_filetype_table[] = {

fs/btrfs/ioctl.c

+10 −3
Original line number Diff line number Diff line
@@ -393,6 +393,7 @@ static noinline int create_subvol(struct inode *dir, 
	struct btrfs_root *new_root;

	struct btrfs_block_rsv block_rsv;

	struct timespec cur_time = CURRENT_TIME;

	struct inode *inode;

	int ret;

	int err;

	u64 objectid;
@@ -554,8 +555,14 @@ static noinline int create_subvol(struct inode *dir, 
	if (err && !ret)

		ret = err;



	if (!ret)

		d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));

	if (!ret) {

		inode = btrfs_lookup_dentry(dir, dentry);

		if (IS_ERR(inode)) {

			ret = PTR_ERR(inode);

			goto out;

		}

		d_instantiate(dentry, inode);

	}

out:

	btrfs_subvolume_release_metadata(root, &block_rsv, qgroup_reserved);

	return ret;
@@ -643,7 +650,7 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir, 
		ret = PTR_ERR(inode);

		goto fail;

	}

	BUG_ON(!inode);



	d_instantiate(dentry, inode);

	ret = 0;

fail: