ceph: eliminate ceph_async_iput()

Now that we don't need to hold session->s_mutex or the snap_rwsem when
calling ceph_check_caps, we can eliminate ceph_async_iput and just use
normal iput calls.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/caps.c

@@ -3142,8 +3142,7 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
 	if (complete_capsnap)
 		wake_up_all(&ci->i_cap_wq);
 	while (put-- > 0) {
-		/* avoid calling iput_final() in osd dispatch threads */
-		ceph_async_iput(inode);
+		iput(inode);
 	}
 }
 
@@ -4131,8 +4130,7 @@ void ceph_handle_caps(struct ceph_mds_session *session,
 	mutex_unlock(&session->s_mutex);
 done_unlocked:
 	ceph_put_string(extra_info.pool_ns);
-	/* avoid calling iput_final() in mds dispatch threads */
-	ceph_async_iput(inode);
+	iput(inode);
 	return;
 
 flush_cap_releases:
@@ -4174,8 +4172,7 @@ void ceph_check_delayed_caps(struct ceph_mds_client *mdsc)
 			spin_unlock(&mdsc->cap_delay_lock);
 			dout("check_delayed_caps on %p\n", inode);
 			ceph_check_caps(ci, 0, NULL);
-			/* avoid calling iput_final() in tick thread */
-			ceph_async_iput(inode);
+			iput(inode);
 			spin_lock(&mdsc->cap_delay_lock);
 		}
 	}

fs/ceph/inode.c

@@ -1566,8 +1566,7 @@ static int readdir_prepopulate_inodes_only(struct ceph_mds_request *req,
 			unlock_new_inode(in);
 		}
 
-		/* avoid calling iput_final() in mds dispatch threads */
-		ceph_async_iput(in);
+		iput(in);
 	}
 
 	return err;
@@ -1764,13 +1763,11 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
 		if (ret < 0) {
 			pr_err("ceph_fill_inode badness on %p\n", in);
 			if (d_really_is_negative(dn)) {
-				/* avoid calling iput_final() in mds
-				 * dispatch threads */
 				if (in->i_state & I_NEW) {
 					ihold(in);
 					discard_new_inode(in);
 				}
-				ceph_async_iput(in);
+				iput(in);
 			}
 			d_drop(dn);
 			err = ret;
@@ -1783,7 +1780,7 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
 			if (ceph_security_xattr_deadlock(in)) {
 				dout(" skip splicing dn %p to inode %p"
 				     " (security xattr deadlock)\n", dn, in);
-				ceph_async_iput(in);
+				iput(in);
 				skipped++;
 				goto next_item;
 			}
@@ -1834,25 +1831,6 @@ bool ceph_inode_set_size(struct inode *inode, loff_t size)
 	return ret;
 }
 
-/*
- * Put reference to inode, but avoid calling iput_final() in current thread.
- * iput_final() may wait for reahahead pages. The wait can cause deadlock in
- * some contexts.
- */
-void ceph_async_iput(struct inode *inode)
-{
-	if (!inode)
-		return;
-	for (;;) {
-		if (atomic_add_unless(&inode->i_count, -1, 1))
-			break;
-		if (queue_work(ceph_inode_to_client(inode)->inode_wq,
-			       &ceph_inode(inode)->i_work))
-			break;
-		/* queue work failed, i_count must be at least 2 */
-	}
-}
-
 void ceph_queue_inode_work(struct inode *inode, int work_bit)
 {
 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);

fs/ceph/mds_client.c

@@ -824,14 +824,13 @@ void ceph_mdsc_release_request(struct kref *kref)
 		ceph_msg_put(req->r_reply);
 	if (req->r_inode) {
 		ceph_put_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
-		/* avoid calling iput_final() in mds dispatch threads */
-		ceph_async_iput(req->r_inode);
+		iput(req->r_inode);
 	}
 	if (req->r_parent) {
 		ceph_put_cap_refs(ceph_inode(req->r_parent), CEPH_CAP_PIN);
-		ceph_async_iput(req->r_parent);
+		iput(req->r_parent);
 	}
-	ceph_async_iput(req->r_target_inode);
+	iput(req->r_target_inode);
 	if (req->r_dentry)
 		dput(req->r_dentry);
 	if (req->r_old_dentry)
@@ -845,7 +844,7 @@ void ceph_mdsc_release_request(struct kref *kref)
 		 */
 		ceph_put_cap_refs(ceph_inode(req->r_old_dentry_dir),
 				  CEPH_CAP_PIN);
-		ceph_async_iput(req->r_old_dentry_dir);
+		iput(req->r_old_dentry_dir);
 	}
 	kfree(req->r_path1);
 	kfree(req->r_path2);
@@ -960,8 +959,7 @@ static void __unregister_request(struct ceph_mds_client *mdsc,
 	}
 
 	if (req->r_unsafe_dir) {
-		/* avoid calling iput_final() in mds dispatch threads */
-		ceph_async_iput(req->r_unsafe_dir);
+		iput(req->r_unsafe_dir);
 		req->r_unsafe_dir = NULL;
 	}
 
@@ -1132,7 +1130,7 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
 		cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
 	if (!cap) {
 		spin_unlock(&ci->i_ceph_lock);
-		ceph_async_iput(inode);
+		iput(inode);
 		goto random;
 	}
 	mds = cap->session->s_mds;
@@ -1141,9 +1139,7 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
 	     cap == ci->i_auth_cap ? "auth " : "", cap);
 	spin_unlock(&ci->i_ceph_lock);
 out:
-	/* avoid calling iput_final() while holding mdsc->mutex or
-	 * in mds dispatch threads */
-	ceph_async_iput(inode);
+	iput(inode);
 	return mds;
 
 random:
@@ -1546,9 +1542,7 @@ int ceph_iterate_session_caps(struct ceph_mds_session *session,
 		spin_unlock(&session->s_cap_lock);
 
 		if (last_inode) {
-			/* avoid calling iput_final() while holding
-			 * s_mutex or in mds dispatch threads */
-			ceph_async_iput(last_inode);
+			iput(last_inode);
 			last_inode = NULL;
 		}
 		if (old_cap) {
@@ -1582,7 +1576,7 @@ int ceph_iterate_session_caps(struct ceph_mds_session *session,
 	session->s_cap_iterator = NULL;
 	spin_unlock(&session->s_cap_lock);
 
-	ceph_async_iput(last_inode);
+	iput(last_inode);
 	if (old_cap)
 		ceph_put_cap(session->s_mdsc, old_cap);
 
@@ -1722,8 +1716,7 @@ static void remove_session_caps(struct ceph_mds_session *session)
 			spin_unlock(&session->s_cap_lock);
 
 			inode = ceph_find_inode(sb, vino);
-			 /* avoid calling iput_final() while holding s_mutex */
-			ceph_async_iput(inode);
+			iput(inode);
 
 			spin_lock(&session->s_cap_lock);
 		}
@@ -4369,8 +4362,7 @@ static void handle_lease(struct ceph_mds_client *mdsc,
 
 out:
 	mutex_unlock(&session->s_mutex);
-	/* avoid calling iput_final() in mds dispatch threads */
-	ceph_async_iput(inode);
+	iput(inode);
 	return;
 
 bad:

fs/ceph/quota.c

@@ -74,8 +74,7 @@ void ceph_handle_quota(struct ceph_mds_client *mdsc,
 		            le64_to_cpu(h->max_files));
 	spin_unlock(&ci->i_ceph_lock);
 
-	/* avoid calling iput_final() in dispatch thread */
-	ceph_async_iput(inode);
+	iput(inode);
 }
 
 static struct ceph_quotarealm_inode *
@@ -247,8 +246,7 @@ static struct ceph_snap_realm *get_quota_realm(struct ceph_mds_client *mdsc,
 
 		ci = ceph_inode(in);
 		has_quota = __ceph_has_any_quota(ci);
-		/* avoid calling iput_final() while holding mdsc->snap_rwsem */
-		ceph_async_iput(in);
+		iput(in);
 
 		next = realm->parent;
 		if (has_quota || !next)
@@ -383,8 +381,7 @@ static bool check_quota_exceeded(struct inode *inode, enum quota_check_op op,
 			pr_warn("Invalid quota check op (%d)\n", op);
 			exceeded = true; /* Just break the loop */
 		}
-		/* avoid calling iput_final() while holding mdsc->snap_rwsem */
-		ceph_async_iput(in);
+		iput(in);
 
 		next = realm->parent;
 		if (exceeded || !next)

fs/ceph/snap.c

@@ -677,15 +677,13 @@ static void queue_realm_cap_snaps(struct ceph_snap_realm *realm)
 		if (!inode)
 			continue;
 		spin_unlock(&realm->inodes_with_caps_lock);
-		/* avoid calling iput_final() while holding
-		 * mdsc->snap_rwsem or in mds dispatch threads */
-		ceph_async_iput(lastinode);
+		iput(lastinode);
 		lastinode = inode;
 		ceph_queue_cap_snap(ci);
 		spin_lock(&realm->inodes_with_caps_lock);
 	}
 	spin_unlock(&realm->inodes_with_caps_lock);
-	ceph_async_iput(lastinode);
+	iput(lastinode);
 
 	dout("queue_realm_cap_snaps %p %llx done\n", realm, realm->ino);
 }
@@ -839,9 +837,7 @@ static void flush_snaps(struct ceph_mds_client *mdsc)
 		ihold(inode);
 		spin_unlock(&mdsc->snap_flush_lock);
 		ceph_flush_snaps(ci, &session);
-		/* avoid calling iput_final() while holding
-		 * session->s_mutex or in mds dispatch threads */
-		ceph_async_iput(inode);
+		iput(inode);
 		spin_lock(&mdsc->snap_flush_lock);
 	}
 	spin_unlock(&mdsc->snap_flush_lock);
@@ -982,14 +978,12 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc,
 			ceph_get_snap_realm(mdsc, realm);
 			ceph_put_snap_realm(mdsc, oldrealm);
 
-			/* avoid calling iput_final() while holding
-			 * mdsc->snap_rwsem or mds in dispatch threads */
-			ceph_async_iput(inode);
+			iput(inode);
 			continue;
 
 skip_inode:
 			spin_unlock(&ci->i_ceph_lock);
-			ceph_async_iput(inode);
+			iput(inode);
 		}
 
 		/* we may have taken some of the old realm's children. */

fs/ceph/super.h

@@ -988,8 +988,6 @@ extern int ceph_inode_holds_cap(struct inode *inode, int mask);
 extern bool ceph_inode_set_size(struct inode *inode, loff_t size);
 extern void __ceph_do_pending_vmtruncate(struct inode *inode);
 
-extern void ceph_async_iput(struct inode *inode);
-
 void ceph_queue_inode_work(struct inode *inode, int work_bit);
 
 static inline void ceph_queue_vmtruncate(struct inode *inode)