From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Tue, 25 Oct 2011 11:59:47 +0000 (+0200)
Subject: VFS: Fix the remaining automounter semantics regressions
X-Git-Tag: firefly_0821_release~7541^2~2432
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=6c36547293e6c46fe5df46e5e1b9ce9babb9eb37;p=firefly-linux-kernel-4.4.55.git

VFS: Fix the remaining automounter semantics regressions

commit 815d405ceff0d6964683f033e18b9b23a88fba87 upstream.

The concensus seems to be that system calls such as stat() etc should
not trigger an automount.  Neither should the l* versions.

This patch therefore adds a LOOKUP_AUTOMOUNT flag to tag those lookups
that _should_ trigger an automount on the last path element.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
[ Edited to leave out the cases that are already covered by LOOKUP_OPEN,
  LOOKUP_DIRECTORY and LOOKUP_CREATE - all of which also fundamentally
  force automounting for their own reasons   - Linus ]

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/fs/namespace.c b/fs/namespace.c
index 304a55d0aa82..537dd96bea08 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1758,7 +1758,7 @@ static int do_loopback(struct path *path, char *old_name,
 		return err;
 	if (!old_name || !*old_name)
 		return -EINVAL;
-	err = kern_path(old_name, LOOKUP_FOLLOW, &old_path);
+	err = kern_path(old_name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &old_path);
 	if (err)
 		return err;
 
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index ce40e5c568ba..858d31be29c8 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2793,7 +2793,7 @@ static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
 		goto out_put_mnt_ns;
 
 	ret = vfs_path_lookup(root_mnt->mnt_root, root_mnt,
-			export_path, LOOKUP_FOLLOW, nd);
+			export_path, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, nd);
 
 	nfs_referral_loop_unprotect();
 	put_mnt_ns(ns_private);
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index b34bdb25490c..10b6be3ca280 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -355,7 +355,7 @@ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
 	 * resolution (think about autofs) and thus deadlocks could arise.
 	 */
 	if (cmds == Q_QUOTAON) {
-		ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW, &path);
+		ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
 		if (ret)
 			pathp = ERR_PTR(ret);
 		else