4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Yan, Zheng <z...@redhat.com>
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 <z...@redhat.com>
Cc: Nikolay Borisov <ker...@kyup.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
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) &&
