From b93e0acc5001b80153cb0c7efcdcc53cc56aac4a Mon Sep 17 00:00:00 2001 From: Jari Ruusu Date: Sat, 13 Jun 2015 19:01:31 +0300 Subject: d_walk() might skip too much 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. Signed-off-by: Jari Ruusu Cc: Willy Tarreau Signed-off-by: Greg Kroah-Hartman --- fs/dcache.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'fs') diff --git a/fs/dcache.c b/fs/dcache.c index e2800926ae05..38c4a302fab4 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -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; } -- cgit v1.2.3