Commit b307f06d authored by David Sterba's avatar David Sterba
Browse files

btrfs: simplify generation check in btrfs_get_dentry 



Callers that pass non-zero generation always want to perform the
generation check, we can simply encode that in one parameter and drop
check_generation. Add function documentation.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 63a7cb13

fs/btrfs/export.c

+17 −6
Original line number Diff line number Diff line
@@ -57,9 +57,20 @@ static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len, 
	return type;

}



/*

 * Read dentry of inode with @objectid from filesystem root @root_objectid.

 *

 * @sb:             the filesystem super block

 * @objectid:       inode objectid

 * @root_objectid:  object id of the subvolume root where to look up the inode

 * @generation:     optional, if not zero, verify that the found inode

 *                  generation matches

 *

 * Return dentry alias for the inode, otherwise an error. In case the

 * generation does not match return ESTALE.

 */

struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,

				u64 root_objectid, u64 generation,

				int check_generation)

				u64 root_objectid, u64 generation)

{

	struct btrfs_fs_info *fs_info = btrfs_sb(sb);

	struct btrfs_root *root;
@@ -77,7 +88,7 @@ struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, 
	if (IS_ERR(inode))

		return ERR_CAST(inode);



	if (check_generation && generation != inode->i_generation) {

	if (generation != 0 && generation != inode->i_generation) {

		iput(inode);

		return ERR_PTR(-ESTALE);

	}
@@ -106,7 +117,7 @@ static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh, 
	objectid = fid->parent_objectid;

	generation = fid->parent_gen;



	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);

	return btrfs_get_dentry(sb, objectid, root_objectid, generation);

}



static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
@@ -128,7 +139,7 @@ static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh, 
	root_objectid = fid->root_objectid;

	generation = fid->gen;



	return btrfs_get_dentry(sb, objectid, root_objectid, generation, 1);

	return btrfs_get_dentry(sb, objectid, root_objectid, generation);

}



struct dentry *btrfs_get_parent(struct dentry *child)
@@ -188,7 +199,7 @@ struct dentry *btrfs_get_parent(struct dentry *child) 


	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {

		return btrfs_get_dentry(fs_info->sb, key.objectid,

					found_key.offset, 0, 0);

					found_key.offset, 0);

	}



	return d_obtain_alias(btrfs_iget(fs_info->sb, key.objectid, root));

fs/btrfs/export.h

+1 −2
Original line number Diff line number Diff line
@@ -19,8 +19,7 @@ struct btrfs_fid { 
} __attribute__ ((packed));



struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,

				u64 root_objectid, u64 generation,

				int check_generation);

				u64 root_objectid, u64 generation);

struct dentry *btrfs_get_parent(struct dentry *child);



#endif

fs/btrfs/ioctl.c

+1 −1
Original line number Diff line number Diff line
@@ -3274,7 +3274,7 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file, 


			dentry = btrfs_get_dentry(fs_info->sb,

					BTRFS_FIRST_FREE_OBJECTID,

					vol_args2->subvolid, 0, 0);

					vol_args2->subvolid, 0);

			if (IS_ERR(dentry)) {

				err = PTR_ERR(dentry);

				goto out_drop_write;