From f2cdc67f79a780abd0c5b53efaf15c4f003ec89c Mon Sep 17 00:00:00 2001
From: Erez Zadok <ezk@cs.sunysb.edu>
Date: Thu, 21 May 2009 21:02:31 -0400
Subject: [PATCH] Unionfs: lock base inode mutex around lookup_one_len

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
---
 fs/unionfs/commonfops.c |  2 +-
 fs/unionfs/copyup.c     |  4 ++--
 fs/unionfs/lookup.c     |  4 ++--
 fs/unionfs/union.h      | 11 +++++++++++
 fs/unionfs/whiteout.c   |  8 ++++----
 5 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c
index e9dc23c5478..f1d66b3ca55 100644
--- a/fs/unionfs/commonfops.c
+++ b/fs/unionfs/commonfops.c
@@ -62,7 +62,7 @@ retry:
 		pr_debug("unionfs: trying to rename %s to %s\n",
 			 dentry->d_name.name, name);
 
-		tmp_dentry = lookup_one_len(name, lower_dentry->d_parent,
+		tmp_dentry = lookup_lck_len(name, lower_dentry->d_parent,
 					    nlen);
 		if (IS_ERR(tmp_dentry)) {
 			err = PTR_ERR(tmp_dentry);
diff --git a/fs/unionfs/copyup.c b/fs/unionfs/copyup.c
index 3d0c0ca0bec..c43cc7f133c 100644
--- a/fs/unionfs/copyup.c
+++ b/fs/unionfs/copyup.c
@@ -778,7 +778,7 @@ begin:
 
 	if (child_dentry != dentry) {
 		/* lookup child in the underlying file system */
-		lower_dentry = lookup_one_len(childname, lower_parent_dentry,
+		lower_dentry = lookup_lck_len(childname, lower_parent_dentry,
 					      childnamelen);
 		if (IS_ERR(lower_dentry))
 			goto out;
@@ -787,7 +787,7 @@ begin:
 		 * Is the name a whiteout of the child name ?  lookup the
 		 * whiteout child in the underlying file system
 		 */
-		lower_dentry = lookup_one_len(name, lower_parent_dentry,
+		lower_dentry = lookup_lck_len(name, lower_parent_dentry,
 					      strlen(name));
 		if (IS_ERR(lower_dentry))
 			goto out;
diff --git a/fs/unionfs/lookup.c b/fs/unionfs/lookup.c
index 9d887ac5ff9..6361541a5ce 100644
--- a/fs/unionfs/lookup.c
+++ b/fs/unionfs/lookup.c
@@ -50,7 +50,7 @@ struct dentry *__lookup_one(struct dentry *base, struct vfsmount *mnt,
 		  * it's safe to call lookup_one_len (which doesn't take a
 		  * vfsmount).
 		  */
-		dentry = lookup_one_len(name, base, strlen(name));
+		dentry = lookup_lck_len(name, base, strlen(name));
 		if (new_mnt)
 			*new_mnt = mntget(lower_nd.path.mnt);
 		break;
@@ -469,7 +469,7 @@ struct dentry *unionfs_lookup_full(struct dentry *dentry,
 		if (!S_ISDIR(lower_dir_dentry->d_inode->i_mode))
 			goto out; /* XXX: should be BUG_ON */
 		/* XXX: do we need to cross bind mounts here? */
-		lower_dentry = lookup_one_len(name, lower_dir_dentry, namelen);
+		lower_dentry = lookup_lck_len(name, lower_dir_dentry, namelen);
 		if (IS_ERR(lower_dentry)) {
 			err = PTR_ERR(lower_dentry);
 			goto out;
diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
index 1b2b86f4acf..1a05f63c5f9 100644
--- a/fs/unionfs/union.h
+++ b/fs/unionfs/union.h
@@ -553,6 +553,17 @@ static inline void unlock_dir(struct dentry *dir)
 	dput(dir);
 }
 
+/* lock base inode mutex before calling lookup_one_len */
+static inline struct dentry *lookup_lck_len(const char *name,
+					    struct dentry *base, int len)
+{
+	struct dentry *d;
+	mutex_lock(&base->d_inode->i_mutex);
+	d = lookup_one_len(name, base, len);
+	mutex_unlock(&base->d_inode->i_mutex);
+	return d;
+}
+
 static inline struct vfsmount *unionfs_mntget(struct dentry *dentry,
 					      int bindex)
 {
diff --git a/fs/unionfs/whiteout.c b/fs/unionfs/whiteout.c
index a55684d98ae..626006a3735 100644
--- a/fs/unionfs/whiteout.c
+++ b/fs/unionfs/whiteout.c
@@ -101,7 +101,7 @@ struct dentry *lookup_whiteout(const char *name, struct dentry *lower_parent)
 	}
 
 	/* check if whiteout exists in this branch: lookup .wh.foo */
-	wh_dentry = lookup_one_len(whname, lower_parent, strlen(whname));
+	wh_dentry = lookup_lck_len(whname, lower_parent, strlen(whname));
 	if (IS_ERR(wh_dentry)) {
 		err = PTR_ERR(wh_dentry);
 		goto out;
@@ -311,7 +311,7 @@ int create_whiteout(struct dentry *dentry, int start)
 		}
 
 		lower_wh_dentry =
-			lookup_one_len(name, lower_dentry->d_parent,
+			lookup_lck_len(name, lower_dentry->d_parent,
 				       dentry->d_name.len + UNIONFS_WHLEN);
 		if (IS_ERR(lower_wh_dentry))
 			continue;
@@ -334,7 +334,7 @@ int create_whiteout(struct dentry *dentry, int start)
 		if (!err)
 			err = vfs_create(lower_dir_dentry->d_inode,
 					 lower_wh_dentry,
-					 ~current->fs->umask & S_IRUGO,
+					 current_umask() & S_IRUGO,
 					 &nd);
 		unlock_dir(lower_dir_dentry);
 		dput(lower_wh_dentry);
@@ -397,7 +397,7 @@ static int do_delete_whiteouts(struct dentry *dentry, int bindex,
 
 			strlcpy(p, cursor->name, PATH_MAX - UNIONFS_WHLEN);
 			lower_dentry =
-				lookup_one_len(name, lower_dir_dentry,
+				lookup_lck_len(name, lower_dir_dentry,
 					       cursor->namelen +
 					       UNIONFS_WHLEN);
 			if (IS_ERR(lower_dentry)) {
-- 
2.34.1