diff options
| author | Yan, Zheng <zyan@redhat.com> | 2016-02-26 16:27:13 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-10-07 15:23:42 +0200 |
| commit | f0006eda8e69571fcd8bd657d9c89f30e211e038 (patch) | |
| tree | 647c6a8a885f6e4bbf6aa8159a7c9fc5f4857139 /fs/ceph/inode.c | |
| parent | 9ec153066b081132edb59998c7030f1fb1bd62a8 (diff) | |
ceph: fix race during filling readdir cache
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@redhat.com>
Cc: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/ceph/inode.c')
| -rw-r--r-- | fs/ceph/inode.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index 498dcfa2dcdb..d98536c8abfc 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -1358,15 +1358,20 @@ static int fill_readdir_cache(struct inode *dir, struct dentry *dn, 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) && |