ceph: renew caps for read/write if mds session got killed.

When mds session gets killed, read/write operation may hang.
Client waits for Frw caps, but mds does not know what caps client
wants. To recover this, client sends an open request to mds. The
request will tell mds what caps client wants.

Signed-off-by: Yan, Zheng <zyan@redhat.com>

1 files changed, 33 insertions, 10 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index cfaeef1..fab93c6 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2317,7 +2317,7 @@ again:
 
 	/* make sure file is actually open */
 	file_wanted = __ceph_caps_file_wanted(ci);
-	if ((file_wanted & need) == 0) {
+	if ((file_wanted & need) != need) {
 		dout("try_get_cap_refs need %s file_wanted %s, EBADF\n",
 		     ceph_cap_string(need), ceph_cap_string(file_wanted));
 		*err = -EBADF;
@@ -2412,12 +2412,26 @@ again:
 			goto out_unlock;
 		}
 
-		if (!__ceph_is_any_caps(ci) &&
-		    ACCESS_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN) {
-			dout("get_cap_refs %p forced umount\n", inode);
-			*err = -EIO;
-			ret = 1;
-			goto out_unlock;
+		if (ci->i_ceph_flags & CEPH_I_CAP_DROPPED) {
+			int mds_wanted;
+			if (ACCESS_ONCE(mdsc->fsc->mount_state) ==
+			    CEPH_MOUNT_SHUTDOWN) {
+				dout("get_cap_refs %p forced umount\n", inode);
+				*err = -EIO;
+				ret = 1;
+				goto out_unlock;
+			}
+			mds_wanted = __ceph_caps_mds_wanted(ci);
+			if ((mds_wanted & need) != need) {
+				dout("get_cap_refs %p caps were dropped"
+				     " (session killed?)\n", inode);
+				*err = -ESTALE;
+				ret = 1;
+				goto out_unlock;
+			}
+			if ((mds_wanted & file_wanted) ==
+			    (file_wanted & (CEPH_CAP_FILE_RD|CEPH_CAP_FILE_WR)))
+				ci->i_ceph_flags &= ~CEPH_I_CAP_DROPPED;
 		}
 
 		dout("get_cap_refs %p have %s needed %s\n", inode,
@@ -2487,7 +2501,7 @@ int ceph_get_caps(struct ceph_inode_info *ci, int need, int want,
 			if (err == -EAGAIN)
 				continue;
 			if (err < 0)
-				return err;
+				ret = err;
 		} else {
 			ret = wait_event_interruptible(ci->i_cap_wq,
 					try_get_cap_refs(ci, need, want, endoff,
@@ -2496,8 +2510,15 @@ int ceph_get_caps(struct ceph_inode_info *ci, int need, int want,
 				continue;
 			if (err < 0)
 				ret = err;
-			if (ret < 0)
-				return ret;
+		}
+		if (ret < 0) {
+			if (err == -ESTALE) {
+				/* session was killed, try renew caps */
+				ret = ceph_renew_caps(&ci->vfs_inode);
+				if (ret == 0)
+					continue;
+			}
+			return ret;
 		}
 
 		if (ci->i_inline_version != CEPH_INLINE_NONE &&
@@ -3226,6 +3247,8 @@ retry:
 
 	if (target < 0) {
 		__ceph_remove_cap(cap, false);
+		if (!ci->i_auth_cap)
+			ci->i_ceph_flags |= CEPH_I_CAP_DROPPED;
 		goto out_unlock;
 	}