orangefs: have ..._clean_interrupted_...() wait for copy to/from daemon

* turn all those list_del(&op->list) into list_del_init()
* don't pick ops that are already given up in control device
  ->read()/->write_iter().
* have orangefs_clean_interrupted_operation() notice if op is currently
  being copied to/from daemon (by said ->read()/->write_iter()) and
  wait for that to finish.
* when we are done copying to/from daemon and find that it had been
  given up while we were doing that, wake the waiting ..._clean_interrupted_...

As the result, we are guaranteed that orangefs_clean_interrupted_operation(op)
doesn't return until nobody else can see op.  Moreover, we don't need to play
with op refcounts anymore.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>

3 files changed, 21 insertions, 23 deletions

diff --git a/fs/orangefs/devorangefs-req.c b/fs/orangefs/devorangefs-req.c
index 89c282afeb29..f7914f5d296f 100644
--- a/fs/orangefs/devorangefs-req.c
+++ b/fs/orangefs/devorangefs-req.c
@@ -58,9 +58,9 @@ static struct orangefs_kernel_op_s *orangefs_devreq_remove_op(__u64 tag)
                                  next,
                                  &htable_ops_in_progress[index],
                                  list) {
-                if (op->tag == tag && !op_state_purged(op)) {
+                if (op->tag == tag && !op_state_purged(op) &&
+                    !op_state_given_up(op)) {
                         list_del_init(&op->list);
-                        get_op(op); /* increase ref count. */
                         spin_unlock(&htable_ops_in_progress_lock);
                         return op;
                 }
@@ -133,7 +133,7 @@ restart:
                 __s32 fsid;
                 /* This lock is held past the end of the loop when we break. */
                 spin_lock(&op->lock);
-                if (unlikely(op_state_purged(op))) {
+                if (unlikely(op_state_purged(op) || op_state_given_up(op))) {
                         spin_unlock(&op->lock);
                         continue;
                 }
@@ -199,13 +199,12 @@ restart:
          */
         if (op_state_in_progress(cur_op) || op_state_serviced(cur_op)) {
                 gossip_err("orangefs: ERROR: Current op already queued.\n");
-                list_del(&cur_op->list);
+                list_del_init(&cur_op->list);
                 spin_unlock(&cur_op->lock);
                 spin_unlock(&orangefs_request_list_lock);
                 return -EAGAIN;
         }
         list_del_init(&cur_op->list);
-        get_op(op);
         spin_unlock(&orangefs_request_list_lock);
 
         spin_unlock(&cur_op->lock);
@@ -230,7 +229,7 @@ restart:
         if (unlikely(op_state_given_up(cur_op))) {
                 spin_unlock(&cur_op->lock);
                 spin_unlock(&htable_ops_in_progress_lock);
-                op_release(cur_op);
+                complete(&cur_op->waitq);
                 goto restart;
         }
 
@@ -242,7 +241,6 @@ restart:
         orangefs_devreq_add_op(cur_op);
         spin_unlock(&cur_op->lock);
         spin_unlock(&htable_ops_in_progress_lock);
-        op_release(cur_op);
 
         /* The client only asks to read one size buffer. */
         return MAX_DEV_REQ_UPSIZE;
@@ -258,10 +256,12 @@ error:
         if (likely(!op_state_given_up(cur_op))) {
                 set_op_state_waiting(cur_op);
                 list_add(&cur_op->list, &orangefs_request_list);
+                spin_unlock(&cur_op->lock);
+        } else {
+                spin_unlock(&cur_op->lock);
+                complete(&cur_op->waitq);
         }
-        spin_unlock(&cur_op->lock);
         spin_unlock(&orangefs_request_list_lock);
-        op_release(cur_op);
         return -EFAULT;
 }
 
@@ -405,11 +405,11 @@ wakeup:
                 put_cancel(op);
         } else if (unlikely(op_state_given_up(op))) {
                 spin_unlock(&op->lock);
+                complete(&op->waitq);
         } else {
                 set_op_state_serviced(op);
                 spin_unlock(&op->lock);
         }
-        op_release(op);
         return ret;
 
 Efault:
diff --git a/fs/orangefs/orangefs-kernel.h b/fs/orangefs/orangefs-kernel.h
index 1d20eadaefd8..7d0c8b3afc7e 100644
--- a/fs/orangefs/orangefs-kernel.h
+++ b/fs/orangefs/orangefs-kernel.h
@@ -259,7 +259,7 @@ static inline void set_op_state_purged(struct orangefs_kernel_op_s *op)
 {
         spin_lock(&op->lock);
         if (unlikely(op_is_cancel(op))) {
-                list_del(&op->list);
+                list_del_init(&op->list);
                 spin_unlock(&op->lock);
                 put_cancel(op);
         } else {
diff --git a/fs/orangefs/waitqueue.c b/fs/orangefs/waitqueue.c
index d980240b0fa7..3f9e43066444 100644
--- a/fs/orangefs/waitqueue.c
+++ b/fs/orangefs/waitqueue.c
@@ -208,15 +208,20 @@ static void orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s
          * Called with op->lock held.
          */
         op->op_state |= OP_VFS_STATE_GIVEN_UP;
-
-        if (op_state_waiting(op)) {
+        /* from that point on it can't be moved by anybody else */
+        if (list_empty(&op->list)) {
+                /* caught copying to/from daemon */
+                BUG_ON(op_state_serviced(op));
+                spin_unlock(&op->lock);
+                wait_for_completion(&op->waitq);
+        } else if (op_state_waiting(op)) {
                 /*
                  * upcall hasn't been read; remove op from upcall request
                  * list.
                  */
                 spin_unlock(&op->lock);
                 spin_lock(&orangefs_request_list_lock);
-                list_del(&op->list);
+                list_del_init(&op->list);
                 spin_unlock(&orangefs_request_list_lock);
                 gossip_debug(GOSSIP_WAIT_DEBUG,
                              "Interrupted: Removed op %p from request_list\n",
@@ -225,23 +230,16 @@ static void orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s
                 /* op must be removed from the in progress htable */
                 spin_unlock(&op->lock);
                 spin_lock(&htable_ops_in_progress_lock);
-                list_del(&op->list);
+                list_del_init(&op->list);
                 spin_unlock(&htable_ops_in_progress_lock);
                 gossip_debug(GOSSIP_WAIT_DEBUG,
                              "Interrupted: Removed op %p"
                              " from htable_ops_in_progress\n",
                              op);
-        } else if (!op_state_serviced(op)) {
+        } else {
                 spin_unlock(&op->lock);
                 gossip_err("interrupted operation is in a weird state 0x%x\n",
                            op->op_state);
-        } else {
-                /*
-                 * It is not intended for execution to flow here,
-                 * but having this unlock here makes sparse happy.
-                 */
-                gossip_err("%s: can't get here.\n", __func__);
-                spin_unlock(&op->lock);
         }
         reinit_completion(&op->waitq);
 }