Patch "Re: [PATCH 3.10 14/46] d_walk() might skip too much" has been added to the 3.10-stable tree

This is a note to let you know that I've just added the patch titled

    Re: [PATCH 3.10 14/46] d_walk() might skip too much

to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
d_walk-might-skip-too-much.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Date: Sat, 13 Jun 2015 19:01:31 +0300
Subject: Re: [PATCH 3.10 14/46] d_walk() might skip too much
From: Jari Ruusu <[email protected]>

From: Jari Ruusu <[email protected]>

When Al Viro's VFS deadlock fix "deal with deadlock in d_walk()" was backported to 3.10.y 3.4.y and 3.2.y stable kernel brances, the deadlock fix was copied to 3 different places. Later, a bug in that code was discovered. Al Viro's fix involved fixing only one part of code in mainline kernel. That fix is called "d_walk() might skip too much".

3.10.y 3.4.y and 3.2.y stable kernel brances need that later fix copied to 3 different places. Greg Kroah-Hartman included Al Viro's "d_walk() might skip too much" fix only once in 3.10.80 kernel, leaving 2 more places without a fix.

The patch below was not written by me. I only applied Al Viro's "d_walk() might skip too much" fix 2 more times to 3.10.80 kernel, and cheched that the fixes went to correct places. With this patch applied, all 3 places that I am aware of 3.10.y stable branch are now fixed.

---
 fs/dcache.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

@@ -1053,13 +1053,13 @@ ascend:
 		/* might go back up the wrong parent if we have had a rename. */
 		if (!locked && read_seqretry(&rename_lock, seq))
 			goto rename_retry;
-		next = child->d_child.next;
-		while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED)) {
+		/* go into the first sibling still alive */
+		do {
+			next = child->d_child.next;
 			if (next == &this_parent->d_subdirs)
 				goto ascend;
 			child = list_entry(next, struct dentry, d_child);
-			next = next->next;
-		}
+		} while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
 		rcu_read_unlock();
 		goto resume;
 	}

@@ -2977,13 +2977,13 @@ ascend:
 		/* might go back up the wrong parent if we have had a rename. */
 		if (!locked && read_seqretry(&rename_lock, seq))
 			goto rename_retry;
-		next = child->d_child.next;
-		while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED)) {
+		/* go into the first sibling still alive */
+		do {
+			next = child->d_child.next;
 			if (next == &this_parent->d_subdirs)
 				goto ascend;
 			child = list_entry(next, struct dentry, d_child);
-			next = next->next;
-		}
+		} while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
 		rcu_read_unlock();
 		goto resume;
 	}

Patches currently in stable-queue which might be from [email protected] are

queue-3.10/d_walk-might-skip-too-much.patch