[3.19.y-ckt stable] Patch "d_walk() might skip too much" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Tue Jul 7 00:10:49 UTC 2015
This is a note to let you know that I have just added a patch titled
d_walk() might skip too much
to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue
This patch is scheduled to be released in version 3.19.8-ckt3.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From ffb35a40254af3d5a6f28d5c27d63df691dd55b0 Mon Sep 17 00:00:00 2001
From: Al Viro <viro at zeniv.linux.org.uk>
Date: Thu, 28 May 2015 23:09:19 -0400
Subject: d_walk() might skip too much
commit 2159184ea01e4ae7d15f2017e296d4bc82d5aeb0 upstream.
when we find that a child has died while we'd been trying to ascend,
we should go into the first live sibling itself, rather than its sibling.
Off-by-one in question had been introduced in "deal with deadlock in
d_walk()" and the fix needs to be backported to all branches this one
has been backported to.
Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
fs/dcache.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index e368d4f..aa8ff8d 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1094,13 +1094,13 @@ ascend:
/* might go back up the wrong parent if we have had a rename. */
if (need_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;
}
--
1.9.1
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