From: Ian Kent <ikent@redhat.com>
Date: Wed, 18 Mar 2009 16:04:56 +0900
Subject: [fs] autofs4: track uid and gid of last mount requester
Message-id: 20090318070456.9081.88327.stgit@zeus.themaw.net
O-Subject: [RHEL 5.4 PATCH 1/5] autofs4 - track uid and gid of last mount requester
Bugzilla: 452120
RH-Acked-by: Jeff Layton <jlayton@redhat.com>

From: Ian Kent <raven@themaw.net>

This patch is the first of four patches needed to addresses bug 452120.

Patch to track the uid and gid of the last process to request a mount
for on an autofs dentry.

Signed-off-by: Ian Kent <raven@themaw.net>

diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index d599c69..d39c197 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -65,6 +65,9 @@ struct autofs_info {
 	unsigned long last_used;
 	atomic_t count;
 
+	uid_t uid;
+	gid_t gid;
+
 	mode_t	mode;
 	size_t	size;
 
diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c
index 1b700d1..7ced5fc 100644
--- a/fs/autofs4/inode.c
+++ b/fs/autofs4/inode.c
@@ -53,6 +53,8 @@ struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
 		atomic_set(&ino->count, 0);
 	}
 
+	ino->uid = 0;
+	ino->gid = 0;
 	ino->mode = mode;
 	ino->last_used = jiffies;
 
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
index 73ce14b..cc30919 100644
--- a/fs/autofs4/waitq.c
+++ b/fs/autofs4/waitq.c
@@ -453,6 +453,40 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
 
 	status = wq->status;
 
+	/*
+	 * For direct and offset mounts we need to track the requester's
+	 * uid and gid in the dentry info struct. This is so it can be
+	 * supplied, on request, by the misc device ioctl interface.
+	 * This is needed during daemon resatart when reconnecting
+	 * to existing, active, autofs mounts. The uid and gid (and
+	 * related string values) may be used for macro substitution
+	 * in autofs mount maps.
+	 */
+	if (!status) {
+		struct autofs_info *ino;
+		struct dentry *de = NULL;
+
+		/* direct mount or browsable map */
+		ino = autofs4_dentry_ino(dentry);
+		if (!ino) {
+			/* If not lookup actual dentry used */
+			de = d_lookup(dentry->d_parent, &dentry->d_name);
+			if (de)
+				ino = autofs4_dentry_ino(de);
+		}
+
+		/* Set mount requester */
+		if (ino) {
+			spin_lock(&sbi->fs_lock);
+			ino->uid = wq->uid;
+			ino->gid = wq->gid;
+			spin_unlock(&sbi->fs_lock);
+		}
+
+		if (de)
+			dput(de);
+	}
+
 	/* Are we the last process to need status? */
 	mutex_lock(&sbi->wq_mutex);
 	if (!--wq->wait_ctr)