ceph: take i_mutex before getting Fw cap
There is deadlock as illustrated bellow. The fix is taking i_mutex
before getting Fw cap reference.
write truncate MDS
--------------------- -------------------- --------------
get Fw cap
lock i_mutex
lock i_mutex (blocked)
request setattr.size ->
<- revoke Fw cap
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index f956310..da0f9b8 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2052,6 +2052,13 @@
goto out;
}
+ /* finish pending truncate */
+ while (ci->i_truncate_pending) {
+ spin_unlock(&ci->i_ceph_lock);
+ __ceph_do_pending_vmtruncate(inode, !(need & CEPH_CAP_FILE_WR));
+ spin_lock(&ci->i_ceph_lock);
+ }
+
if (need & CEPH_CAP_FILE_WR) {
if (endoff >= 0 && endoff > (loff_t)ci->i_max_size) {
dout("get_cap_refs %p endoff %llu > maxsize %llu\n",
@@ -2073,12 +2080,6 @@
}
have = __ceph_caps_issued(ci, &implemented);
- /*
- * disallow writes while a truncate is pending
- */
- if (ci->i_truncate_pending)
- have &= ~CEPH_CAP_FILE_WR;
-
if ((have & need) == need) {
/*
* Look at (implemented & ~have & not) so that we keep waiting