From cfaf86ab6ccdf0acf47ebe474a4a844114bc0e10 Mon Sep 17 00:00:00 2001 From: Ian Kent Date: Thu, 24 Nov 2016 08:03:42 +1100 Subject: autofs: use path_is_mountpoint() to fix unreliable d_mountpoint() checks If an automount mount is clone(2)ed into a file system that is propagation private, when it later expires in the originating namespace, subsequent calls to autofs ->d_automount() for that dentry in the original namespace will return ELOOP until the mount is umounted in the cloned namespace. Now that a struct path is available where needed use path_is_mountpoint() instead of d_mountpoint() so we don't get false positives when checking if a dentry is a mount point in the current namespace. Link: http://lkml.kernel.org/r/20161011053418.27645.15241.stgit@pluto.themaw.net Signed-off-by: Ian Kent Cc: Al Viro Cc: Eric W. Biederman Cc: Omar Sandoval Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- fs/autofs4/root.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'fs/autofs4/root.c') diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 0e9881552881..9355608cb495 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -123,7 +123,7 @@ static int autofs4_dir_open(struct inode *inode, struct file *file) * it. */ spin_lock(&sbi->lookup_lock); - if (!d_mountpoint(dentry) && simple_empty(dentry)) { + if (!path_is_mountpoint(&file->f_path) && simple_empty(dentry)) { spin_unlock(&sbi->lookup_lock); return -ENOENT; } @@ -372,15 +372,15 @@ static struct vfsmount *autofs4_d_automount(struct path *path) /* * If the dentry is a symlink it's equivalent to a directory - * having d_mountpoint() true, so there's no need to call back - * to the daemon. + * having path_is_mountpoint() true, so there's no need to call + * back to the daemon. */ if (d_really_is_positive(dentry) && d_is_symlink(dentry)) { spin_unlock(&sbi->fs_lock); goto done; } - if (!d_mountpoint(dentry)) { + if (!path_is_mountpoint(path)) { /* * It's possible that user space hasn't removed directories * after umounting a rootless multi-mount, although it @@ -434,7 +434,7 @@ static int autofs4_d_manage(const struct path *path, bool rcu_walk) /* The daemon never waits. */ if (autofs4_oz_mode(sbi)) { - if (!d_mountpoint(dentry)) + if (!path_is_mountpoint(path)) return -EISDIR; return 0; } @@ -463,7 +463,7 @@ static int autofs4_d_manage(const struct path *path, bool rcu_walk) if (ino->flags & AUTOFS_INF_WANT_EXPIRE) return 0; - if (d_mountpoint(dentry)) + if (path_is_mountpoint(path)) return 0; inode = d_inode_rcu(dentry); if (inode && S_ISLNK(inode->i_mode)) @@ -490,7 +490,7 @@ static int autofs4_d_manage(const struct path *path, bool rcu_walk) * we can avoid needless calls ->d_automount() and avoid * an incorrect ELOOP error return. */ - if ((!d_mountpoint(dentry) && !simple_empty(dentry)) || + if ((!path_is_mountpoint(path) && !simple_empty(dentry)) || (d_really_is_positive(dentry) && d_is_symlink(dentry))) status = -EISDIR; } -- cgit v1.2.3