[131/262] VFS: Fix the remaining automounter semantics regressions

From: Greg KH
Date: Thu Nov 10 2011 - 00:03:49 EST


3.0-stable review patch. If anyone has any objections, please let me know.

------------------


From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>

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@xxxxxxxxxx>
[ 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@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
fs/namespace.c | 2 +-
fs/nfs/super.c | 2 +-
fs/quota/quota.c | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)

--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1758,7 +1758,7 @@ static int do_loopback(struct path *path
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;

--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2793,7 +2793,7 @@ static struct dentry *nfs_follow_remote_
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);
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -355,7 +355,7 @@ SYSCALL_DEFINE4(quotactl, unsigned int,
* 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


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