From b307f06d37ca12495e4cfff8d456cd92f045f947 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Tue, 18 Oct 2022 16:06:38 +0200 Subject: [PATCH] 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: Josef Bacik Signed-off-by: David Sterba --- fs/btrfs/export.c | 23 +++++++++++++++++------ fs/btrfs/export.h | 3 +-- fs/btrfs/ioctl.c | 2 +- 3 files changed, 19 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c index fab7eb76e53b..a51a5dfa737c 100644 --- a/fs/btrfs/export.c +++ b/fs/btrfs/export.c @@ -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)); diff --git a/fs/btrfs/export.h b/fs/btrfs/export.h index 5afb7ca42828..eba6bc4f5a61 100644 --- a/fs/btrfs/export.h +++ b/fs/btrfs/export.h @@ -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 diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 5ba2e810dc6e..a482739c1d82 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -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; -- 2.11.0