[PATCH] fs: take dcache_lock inside __d_path

[Christoph Hellwig <hch@lst.de>]

All callers take dcache_lock just around the call to __d_path, so
take the lock into it in preparation of getting rid of dcache_lock.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/dcache.c
===================================================================
--- linux-2.6.orig/fs/dcache.c	2010-10-06 20:44:25.196003402 +0200
+++ linux-2.6/fs/dcache.c	2010-10-06 20:44:42.945004378 +0200
@@ -1994,7 +1994,7 @@ global_root:
  * Returns a pointer into the buffer or an error code if the
  * path was too long.
  *
- * "buflen" should be positive. Caller holds the dcache_lock.
+ * "buflen" should be positive.
  *
  * If path is not reachable from the supplied root, then the value of
  * root is changed (without modifying refcounts).
@@ -2006,10 +2006,12 @@ char *__d_path(const struct path *path,
 	int error;
 
 	prepend(&res, &buflen, "\0", 1);
+	spin_lock(&dcache_lock);
 	error = prepend_path(path, root, &res, &buflen);
+	spin_lock(&dcache_lock);
+
 	if (error)
 		return ERR_PTR(error);
-
 	return res;
 }
 
Index: linux-2.6/fs/seq_file.c
===================================================================
--- linux-2.6.orig/fs/seq_file.c	2010-10-06 20:44:25.189003821 +0200
+++ linux-2.6/fs/seq_file.c	2010-10-06 20:47:19.098003890 +0200
@@ -462,9 +462,7 @@ int seq_path_root(struct seq_file *m, st
 	if (size) {
 		char *p;
 
-		spin_lock(&dcache_lock);
 		p = __d_path(path, root, buf, size);
-		spin_unlock(&dcache_lock);
 		res = PTR_ERR(p);
 		if (!IS_ERR(p)) {
 			char *end = mangle_path(buf, p, esc);
Index: linux-2.6/security/apparmor/path.c
===================================================================
--- linux-2.6.orig/security/apparmor/path.c	2010-10-06 20:44:25.218003402 +0200
+++ linux-2.6/security/apparmor/path.c	2010-10-06 20:44:42.951004029 +0200
@@ -72,10 +72,8 @@ static int d_namespace_path(struct path
 		path_get(&root);
 	}
 
-	spin_lock(&dcache_lock);
 	tmp = root;
 	res = __d_path(path, &tmp, buf, buflen);
-	spin_unlock(&dcache_lock);
 
 	*name = res;
 	/* handle error conditions - and still allow a partial path to
Index: linux-2.6/security/tomoyo/realpath.c
===================================================================
--- linux-2.6.orig/security/tomoyo/realpath.c	2010-10-06 20:44:25.210004100 +0200
+++ linux-2.6/security/tomoyo/realpath.c	2010-10-06 20:44:42.953004029 +0200
@@ -127,10 +127,8 @@ char *tomoyo_realpath_from_path(struct p
 		/* If we don't have a vfsmount, we can't calculate. */
 		if (!path->mnt)
 			break;
-		spin_lock(&dcache_lock);
 		/* go to whatever namespace root we are under */
 		pos = __d_path(path, &ns_root, buf, buf_len);
-		spin_unlock(&dcache_lock);
 		/* Prepend "/proc" prefix if using internal proc vfs mount. */
 		if (!IS_ERR(pos) && (path->mnt->mnt_flags & MNT_INTERNAL) &&
 		    (path->mnt->mnt_sb->s_magic == PROC_SUPER_MAGIC)) {