Commit 8ba64dc3 authored May 31, 2015 by Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs fix from Al Viro:
 "Off-by-one in d_walk()/__dentry_kill() race fix.

  It's very hard to hit; possible in the same conditions as the original
  bug, except that you need the skipped branch to contain all the
  remaining evictables, so that the d_walk()-calling loop in
  d_invalidate() decides there's nothing more to do and doesn't go for
  another pass - otherwise that next pass will sweep the sucker.

  So it's not too urgent, but seeing that the fix is obvious and the
  original commit has spread into all -stable branches..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  d_walk() might skip too much

parents 36a8b9a7 2159184e

fs/dcache.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -1239,13 +1239,13 @@ ascend:
		/* might go back up the wrong parent if we have had a rename. */
		if (need_seqretry(&rename_lock, seq))
		goto rename_retry;
		/* go into the first sibling still alive */
		do {
		next = child->d_child.next;
		while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED)) {
		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;
		}

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