This is a note to let you know that I've just added the patch titled
ceph: fix race during filling readdir cache
to the 4.4-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:
ceph-fix-race-during-filling-readdir-cache.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From af5e5eb574776cdf1b756a27cc437bff257e22fe Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zyan@xxxxxxxxxx>
Date: Fri, 26 Feb 2016 16:27:13 +0800
Subject: ceph: fix race during filling readdir cache
From: Yan, Zheng <zyan@xxxxxxxxxx>
commit af5e5eb574776cdf1b756a27cc437bff257e22fe upstream.
Readdir cache uses page cache to save dentry pointers. When adding
dentry pointers to middle of a page, we need to make sure the page
already exists. Otherwise the beginning part of the page will be
invalid pointers.
Signed-off-by: Yan, Zheng <zyan@xxxxxxxxxx>
Cc: Nikolay Borisov <kernel@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ceph/inode.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1358,15 +1358,20 @@ static int fill_readdir_cache(struct ino
if (!ctl->page || pgoff != page_index(ctl->page)) {
ceph_readdir_cache_release(ctl);
- ctl->page = grab_cache_page(&dir->i_data, pgoff);
+ if (idx == 0)
+ ctl->page = grab_cache_page(&dir->i_data, pgoff);
+ else
+ ctl->page = find_lock_page(&dir->i_data, pgoff);
if (!ctl->page) {
ctl->index = -1;
- return -ENOMEM;
+ return idx == 0 ? -ENOMEM : 0;
}
/* reading/filling the cache are serialized by
* i_mutex, no need to use page lock */
unlock_page(ctl->page);
ctl->dentries = kmap(ctl->page);
+ if (idx == 0)
+ memset(ctl->dentries, 0, PAGE_CACHE_SIZE);
}
if (req->r_dir_release_cnt == atomic64_read(&ci->i_release_count) &&
Patches currently in stable-queue which might be from zyan@xxxxxxxxxx are
queue-4.4/ceph-fix-race-during-filling-readdir-cache.patch
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