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 <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 0e98815..9355608 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -123,7 +123,7 @@
* 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 @@
/*
* 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 @@
/* 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 @@
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 @@
* 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;
}