From bbe6a7c899e7f265c5a6d01a178336a405e98ed6 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 14 Nov 2023 18:52:42 -0500 Subject: bch2_ioctl_subvolume_destroy(): fix locking make it use user_path_locked_at() to get the normal directory protection for modifications, as well as stable ->d_parent and ->d_name in victim Signed-off-by: Al Viro --- fs/bcachefs/fs-ioctl.c | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-) diff --git a/fs/bcachefs/fs-ioctl.c b/fs/bcachefs/fs-ioctl.c index 5a39bcb597a3..c5ab5a2dc9be 100644 --- a/fs/bcachefs/fs-ioctl.c +++ b/fs/bcachefs/fs-ioctl.c @@ -453,33 +453,36 @@ static long bch2_ioctl_subvolume_create(struct bch_fs *c, struct file *filp, static long bch2_ioctl_subvolume_destroy(struct bch_fs *c, struct file *filp, struct bch_ioctl_subvolume arg) { + const char __user *name = (void __user *)(unsigned long)arg.dst_ptr; struct path path; struct inode *dir; + struct dentry *victim; int ret = 0; if (arg.flags) return -EINVAL; - ret = user_path_at(arg.dirfd, - (const char __user *)(unsigned long)arg.dst_ptr, - LOOKUP_FOLLOW, &path); - if (ret) - return ret; + victim = user_path_locked_at(arg.dirfd, name, &path); + if (IS_ERR(victim)) + return PTR_ERR(victim); - if (path.dentry->d_sb->s_fs_info != c) { + if (victim->d_sb->s_fs_info != c) { ret = -EXDEV; goto err; } - - dir = path.dentry->d_parent->d_inode; - - ret = __bch2_unlink(dir, path.dentry, true); - if (ret) + if (!d_is_positive(victim)) { + ret = -ENOENT; goto err; - - fsnotify_rmdir(dir, path.dentry); - d_delete(path.dentry); + } + dir = d_inode(path.dentry); + ret = __bch2_unlink(dir, victim, true); + if (!ret) { + fsnotify_rmdir(dir, victim); + d_delete(victim); + } + inode_unlock(dir); err: + dput(victim); path_put(&path); return ret; } -- cgit v1.2.3