Commit b307f06d authored by David Sterba's avatar David Sterba

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
......@@ -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));
......
......@@ -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
......@@ -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;
......
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