ceph: clean up handle_cap_grant, handle_caps wrt session mutex

Drop session mutex unconditionally in handle_cap_grant, and do the
check_caps from the handle_cap_grant helper.  This avoids using a magic
return value.

Also avoid using a flag variable in the IMPORT case and call
check_caps at the appropriate point.

Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 25 insertions, 32 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 782848632e81..d9e860ff9f3a 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2195,18 +2195,19 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
  * Handle a cap GRANT message from the MDS.  (Note that a GRANT may
  * actually be a revocation if it specifies a smaller cap set.)
  *
- * caller holds s_mutex.
+ * caller holds s_mutex and i_lock, we drop both.
+ *
  * return value:
  *  0 - ok
  *  1 - check_caps on auth cap only (writeback)
  *  2 - check_caps (ack revoke)
  */
-static int handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
-                            struct ceph_mds_session *session,
-                            struct ceph_cap *cap,
-                            struct ceph_buffer *xattr_buf)
+static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
+                             struct ceph_mds_session *session,
+                             struct ceph_cap *cap,
+                             struct ceph_buffer *xattr_buf)
         __releases(inode->i_lock)
-
+        __releases(session->s_mutex)
 {
         struct ceph_inode_info *ci = ceph_inode(inode);
         int mds = session->s_mds;
@@ -2216,7 +2217,7 @@ static int handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
         u64 size = le64_to_cpu(grant->size);
         u64 max_size = le64_to_cpu(grant->max_size);
         struct timespec mtime, atime, ctime;
-        int reply = 0;
+        int check_caps = 0;
         int wake = 0;
         int writeback = 0;
         int revoked_rdcache = 0;
@@ -2329,10 +2330,10 @@ static int handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
                 if ((used & ~newcaps) & CEPH_CAP_FILE_BUFFER)
                         writeback = 1; /* will delay ack */
                 else if (dirty & ~newcaps)
-                        reply = 1;     /* initiate writeback in check_caps */
+                        check_caps = 1;  /* initiate writeback in check_caps */
                 else if (((used & ~newcaps) & CEPH_CAP_FILE_CACHE) == 0 ||
                            revoked_rdcache)
-                        reply = 2;     /* send revoke ack in check_caps */
+                        check_caps = 2;     /* send revoke ack in check_caps */
                 cap->issued = newcaps;
                 cap->implemented |= newcaps;
         } else if (cap->issued == newcaps) {
@@ -2361,7 +2362,14 @@ static int handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
                 ceph_queue_invalidate(inode);
         if (wake)
                 wake_up(&ci->i_cap_wq);
-        return reply;
+
+        if (check_caps == 1)
+                ceph_check_caps(ci, CHECK_CAPS_NODELAY|CHECK_CAPS_AUTHONLY,
+                                session);
+        else if (check_caps == 2)
+                ceph_check_caps(ci, CHECK_CAPS_NODELAY, session);
+        else
+                mutex_unlock(&session->s_mutex);
 }
 
 /*
@@ -2622,9 +2630,7 @@ void ceph_handle_caps(struct ceph_mds_session *session,
         u64 cap_id;
         u64 size, max_size;
         u64 tid;
-        int check_caps = 0;
         void *snaptrace;
-        int r;
 
         dout("handle_caps from mds%d\n", mds);
 
@@ -2669,8 +2675,9 @@ void ceph_handle_caps(struct ceph_mds_session *session,
         case CEPH_CAP_OP_IMPORT:
                 handle_cap_import(mdsc, inode, h, session,
                                   snaptrace, le32_to_cpu(h->snap_trace_len));
-                check_caps = 1; /* we may have sent a RELEASE to the old auth */
-                goto done;
+                ceph_check_caps(ceph_inode(inode), CHECK_CAPS_NODELAY,
+                                session);
+                goto done_unlocked;
         }
 
         /* the rest require a cap */
@@ -2687,19 +2694,8 @@ void ceph_handle_caps(struct ceph_mds_session *session,
         switch (op) {
         case CEPH_CAP_OP_REVOKE:
         case CEPH_CAP_OP_GRANT:
-                r = handle_cap_grant(inode, h, session, cap, msg->middle);
-                if (r == 1) {
-                        ceph_check_caps(ceph_inode(inode),
-                                        CHECK_CAPS_NODELAY|CHECK_CAPS_AUTHONLY,
-                                        session);
-                        session = NULL;
-                } else if (r == 2) {
-                        ceph_check_caps(ceph_inode(inode),
-                                        CHECK_CAPS_NODELAY,
-                                        session);
-                        session = NULL;
-                }
-                break;
+                handle_cap_grant(inode, h, session, cap, msg->middle);
+                goto done_unlocked;
 
         case CEPH_CAP_OP_FLUSH_ACK:
                 handle_cap_flush_ack(inode, tid, h, session, cap);
@@ -2716,11 +2712,8 @@ void ceph_handle_caps(struct ceph_mds_session *session,
         }
 
 done:
-        if (session)
-                mutex_unlock(&session->s_mutex);
-
-        if (check_caps)
-                ceph_check_caps(ceph_inode(inode), CHECK_CAPS_NODELAY, NULL);
+        mutex_unlock(&session->s_mutex);
+done_unlocked:
         if (inode)
                 iput(inode);
         return;