---

yaml --- r: 339343 b: refs/heads/master c: b8a2df6 h: refs/heads/master i: 339341: 7bcfd1d 339339: 05d9432 339335: 09f0aa1 339327: 03f752c v: v3
git-mirror · Nov 19, 2012 · 1e25a39 · 1e25a39
1 parent 675d230
commit 1e25a39
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Showing 2 changed files with 10 additions and 4 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d19e19de48aa0b90c56cd93c8a46ebac46273429
+refs/heads/master: b8a2df6a5b576d04f78f54abf254c283527d8bbc
diff --git a/trunk/kernel/cgroup.c b/trunk/kernel/cgroup.c
@@ -2657,9 +2657,15 @@ static int cgroup_create_file(struct dentry *dentry, umode_t mode,
 		inc_nlink(inode);
 		inc_nlink(dentry->d_parent->d_inode);
 
-		/* start with the directory inode held, so that we can
-		 * populate it without racing with another mkdir */
-		mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
+		/*
+		 * Control reaches here with cgroup_mutex held.
+		 * @inode->i_mutex should nest outside cgroup_mutex but we
+		 * want to populate it immediately without releasing
+		 * cgroup_mutex.  As @inode isn't visible to anyone else
+		 * yet, trylock will always succeed without affecting
+		 * lockdep checks.
+		 */
+		WARN_ON_ONCE(!mutex_trylock(&inode->i_mutex));
 	} else if (S_ISREG(mode)) {
 		inode->i_size = 0;
 		inode->i_fop = &cgroup_file_operations;