ceph: hung on ceph fscache invalidate in some cases

In some cases I'm on my ceph client cluster I'm seeing hunk kernel tasks in
the invalidate page code path. This is due to the fact that we don't check if
the page is marked as cache before calling fscache_wait_on_page_write().

This is the log from the hang

INFO: task XXXXXX:12034 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 ...
Call Trace:
[<ffffffff81568d09>] schedule+0x29/0x70
[<ffffffffa01d4cbd>] __fscache_wait_on_page_write+0x6d/0xb0 [fscache]
[<ffffffff81083520>] ? add_wait_queue+0x60/0x60
[<ffffffffa029a3e9>] ceph_invalidate_fscache_page+0x29/0x50 [ceph]
[<ffffffffa027df00>] ceph_invalidatepage+0x70/0x190 [ceph]
[<ffffffff8112656f>] ? delete_from_page_cache+0x5f/0x70
[<ffffffff81133cab>] truncate_inode_page+0x8b/0x90
[<ffffffff81133ded>] truncate_inode_pages_range.part.12+0x13d/0x620
[<ffffffff8113431d>] truncate_inode_pages_range+0x4d/0x60
[<ffffffff811343b5>] truncate_inode_pages+0x15/0x20
[<ffffffff8119bbf6>] evict+0x1a6/0x1b0
[<ffffffff8119c3f3>] iput+0x103/0x190
 ...

Signed-off-by: Milosz Tanski <milosz@adfin.com>
Reviewed-by: Sage Weil <sage@inktank.com>

diff --git a/fs/ceph/cache.c b/fs/ceph/cache.c
index 6bfe65e0b03831280b0e66e96d616be9ee55e6b1..360b622b0be035e8e6b7a10c9e01d02024246e94 100644 (file)
--- a/fs/ceph/cache.c
+++ b/fs/ceph/cache.c
@@ -324,6 +324,9 @@ void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
 {
        struct ceph_inode_info *ci = ceph_inode(inode);
 
+       if (!PageFsCache(page))
+               return;
+
        fscache_wait_on_page_write(ci->fscache, page);
        fscache_uncache_page(ci->fscache, page);
 }