diff options
author | Eric W. Biederman <ebiederm@xmission.com> | 2015-05-14 00:09:29 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-07-21 20:10:10 +0300 |
commit | b6a80c2dd807e4f6a18d914b1731b8253a8c0728 (patch) | |
tree | 22127e146989f9f478d8c01357c46cbc1effa3de /fs/kernfs/dir.c | |
parent | 594c980a9aea06a8243e41a59c1adbb39b21c46b (diff) | |
download | linux-b6a80c2dd807e4f6a18d914b1731b8253a8c0728.tar.xz |
kernfs: Add support for always empty directories.
commit ea015218f2f7ace2dad9cedd21ed95bdba2886d7 upstream.
Add a new function kernfs_create_empty_dir that can be used to create
directory that can not be modified.
Update the code to use make_empty_dir_inode when reporting a
permanently empty directory to the vfs.
Update the code to not allow adding to permanently empty directories.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/kernfs/dir.c')
-rw-r--r-- | fs/kernfs/dir.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 345b35fd329d..470b29e396ab 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -592,6 +592,9 @@ int kernfs_add_one(struct kernfs_node *kn) goto out_unlock; ret = -ENOENT; + if (parent->flags & KERNFS_EMPTY_DIR) + goto out_unlock; + if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent)) goto out_unlock; @@ -783,6 +786,38 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, return ERR_PTR(rc); } +/** + * kernfs_create_empty_dir - create an always empty directory + * @parent: parent in which to create a new directory + * @name: name of the new directory + * + * Returns the created node on success, ERR_PTR() value on failure. + */ +struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, + const char *name) +{ + struct kernfs_node *kn; + int rc; + + /* allocate */ + kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR, KERNFS_DIR); + if (!kn) + return ERR_PTR(-ENOMEM); + + kn->flags |= KERNFS_EMPTY_DIR; + kn->dir.root = parent->dir.root; + kn->ns = NULL; + kn->priv = NULL; + + /* link in */ + rc = kernfs_add_one(kn); + if (!rc) + return kn; + + kernfs_put(kn); + return ERR_PTR(rc); +} + static struct dentry *kernfs_iop_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) @@ -1254,7 +1289,8 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, mutex_lock(&kernfs_mutex); error = -ENOENT; - if (!kernfs_active(kn) || !kernfs_active(new_parent)) + if (!kernfs_active(kn) || !kernfs_active(new_parent) || + (new_parent->flags & KERNFS_EMPTY_DIR)) goto out; error = 0; |