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| author | Yan, Zheng <zyan@redhat.com> | 2016-02-26 16:27:13 +0800 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2016-03-25 18:51:53 +0100 |
| commit | af5e5eb574776cdf1b756a27cc437bff257e22fe (patch) | |
| tree | c96a1b12b10744491f89d19ac1bfe21f6a519747 /fs/ceph | |
| parent | 89f081730c49a1d3b46359aa0054e6b3b80f47e4 (diff) | |
| download | lwn-af5e5eb574776cdf1b756a27cc437bff257e22fe.tar.gz lwn-af5e5eb574776cdf1b756a27cc437bff257e22fe.zip | |
ceph: fix race during filling readdir cache
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>
Diffstat (limited to 'fs/ceph')
| -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 cec68a6e20df..495decfc4b34 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -1349,15 +1349,20 @@ 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) && |