Merge tag 'afs-fixes-20171124' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull AFS fixes from David Howells:

 - Make AFS file locking work again.

 - Don't write to a page that's being written out, but wait for it to
   complete.

 - Do d_drop() and d_add() in the right places.

 - Put keys on error paths.

 - Remove some redundant code.

* tag 'afs-fixes-20171124' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: remove redundant assignment of dvnode to itself
  afs: cell: Remove unnecessary code in afs_lookup_cell
  afs: Fix signal handling in some file ops
  afs: Fix some dentry handling in dir ops and missing key_puts
  afs: Make afs_write_begin() avoid writing to a page that's being stored
  afs: Fix file locking

fs/afs/cell.c

@@ -207,13 +207,8 @@ struct afs_cell *afs_lookup_cell(struct afs_net *net,
 		rcu_read_lock();
 		cell = afs_lookup_cell_rcu(net, name, namesz);
 		rcu_read_unlock();
-		if (!IS_ERR(cell)) {
-			if (excl) {
-				afs_put_cell(net, cell);
-				return ERR_PTR(-EEXIST);
-			}
+		if (!IS_ERR(cell))
 			goto wait_for_cell;
-		}
 	}
 
 	/* Assume we're probably going to create a cell and preallocate and

fs/afs/dir.c

@@ -765,6 +765,8 @@ static void afs_vnode_new_inode(struct afs_fs_cursor *fc,
 	if (fc->ac.error < 0)
 		return;
 
+	d_drop(new_dentry);
+
 	inode = afs_iget(fc->vnode->vfs_inode.i_sb, fc->key,
 			 newfid, newstatus, newcb, fc->cbi);
 	if (IS_ERR(inode)) {
@@ -775,9 +777,7 @@ static void afs_vnode_new_inode(struct afs_fs_cursor *fc,
 		return;
 	}
 
-	d_instantiate(new_dentry, inode);
-	if (d_unhashed(new_dentry))
-		d_rehash(new_dentry);
+	d_add(new_dentry, inode);
 }
 
 /*
@@ -818,6 +818,8 @@ static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 		ret = afs_end_vnode_operation(&fc);
 		if (ret < 0)
 			goto error_key;
+	} else {
+		goto error_key;
 	}
 
 	key_put(key);
@@ -972,7 +974,7 @@ static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 	struct afs_fs_cursor fc;
 	struct afs_file_status newstatus;
 	struct afs_callback newcb;
-	struct afs_vnode *dvnode = dvnode = AFS_FS_I(dir);
+	struct afs_vnode *dvnode = AFS_FS_I(dir);
 	struct afs_fid newfid;
 	struct key *key;
 	int ret;
@@ -1006,6 +1008,8 @@ static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 		ret = afs_end_vnode_operation(&fc);
 		if (ret < 0)
 			goto error_key;
+	} else {
+		goto error_key;
 	}
 
 	key_put(key);
@@ -1053,7 +1057,7 @@ static int afs_link(struct dentry *from, struct inode *dir,
 	if (afs_begin_vnode_operation(&fc, dvnode, key)) {
 		if (mutex_lock_interruptible_nested(&vnode->io_lock, 1) < 0) {
 			afs_end_vnode_operation(&fc);
-			return -ERESTARTSYS;
+			goto error_key;
 		}
 
 		while (afs_select_fileserver(&fc)) {
@@ -1071,6 +1075,8 @@ static int afs_link(struct dentry *from, struct inode *dir,
 		ret = afs_end_vnode_operation(&fc);
 		if (ret < 0)
 			goto error_key;
+	} else {
+		goto error_key;
 	}
 
 	key_put(key);
@@ -1130,6 +1136,8 @@ static int afs_symlink(struct inode *dir, struct dentry *dentry,
 		ret = afs_end_vnode_operation(&fc);
 		if (ret < 0)
 			goto error_key;
+	} else {
+		goto error_key;
 	}
 
 	key_put(key);
@@ -1180,7 +1188,7 @@ static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
 		if (orig_dvnode != new_dvnode) {
 			if (mutex_lock_interruptible_nested(&new_dvnode->io_lock, 1) < 0) {
 				afs_end_vnode_operation(&fc);
-				return -ERESTARTSYS;
+				goto error_key;
 			}
 		}
 		while (afs_select_fileserver(&fc)) {
@@ -1199,14 +1207,9 @@ static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
 			goto error_key;
 	}
 
-	key_put(key);
-	_leave(" = 0");
-	return 0;
-
 error_key:
 	key_put(key);
 error:
-	d_drop(new_dentry);
 	_leave(" = %d", ret);
 	return ret;
 }

fs/afs/internal.h

@@ -430,6 +430,16 @@ struct afs_volume {
 	u8			name[AFS_MAXVOLNAME + 1]; /* NUL-padded volume name */
 };
 
+enum afs_lock_state {
+	AFS_VNODE_LOCK_NONE,		/* The vnode has no lock on the server */
+	AFS_VNODE_LOCK_WAITING_FOR_CB,	/* We're waiting for the server to break the callback */
+	AFS_VNODE_LOCK_SETTING,		/* We're asking the server for a lock */
+	AFS_VNODE_LOCK_GRANTED,		/* We have a lock on the server */
+	AFS_VNODE_LOCK_EXTENDING,	/* We're extending a lock on the server */
+	AFS_VNODE_LOCK_NEED_UNLOCK,	/* We need to unlock on the server */
+	AFS_VNODE_LOCK_UNLOCKING,	/* We're telling the server to unlock */
+};
+
 /*
  * AFS inode private data
  */
@@ -454,18 +464,16 @@ struct afs_vnode {
 #define AFS_VNODE_ZAP_DATA	3		/* set if vnode's data should be invalidated */
 #define AFS_VNODE_DELETED	4		/* set if vnode deleted on server */
 #define AFS_VNODE_MOUNTPOINT	5		/* set if vnode is a mountpoint symlink */
-#define AFS_VNODE_LOCKING	6		/* set if waiting for lock on vnode */
-#define AFS_VNODE_READLOCKED	7		/* set if vnode is read-locked on the server */
-#define AFS_VNODE_WRITELOCKED	8		/* set if vnode is write-locked on the server */
-#define AFS_VNODE_UNLOCKING	9		/* set if vnode is being unlocked on the server */
-#define AFS_VNODE_AUTOCELL	10		/* set if Vnode is an auto mount point */
-#define AFS_VNODE_PSEUDODIR	11		/* set if Vnode is a pseudo directory */
+#define AFS_VNODE_AUTOCELL	6		/* set if Vnode is an auto mount point */
+#define AFS_VNODE_PSEUDODIR	7 		/* set if Vnode is a pseudo directory */
 
 	struct list_head	wb_keys;	/* List of keys available for writeback */
 	struct list_head	pending_locks;	/* locks waiting to be granted */
 	struct list_head	granted_locks;	/* locks granted on this file */
 	struct delayed_work	lock_work;	/* work to be done in locking */
-	struct key		*unlock_key;	/* key to be used in unlocking */
+	struct key		*lock_key;	/* Key to be used in lock ops */
+	enum afs_lock_state	lock_state : 8;
+	afs_lock_type_t		lock_type : 8;
 
 	/* outstanding callback notification on this file */
 	struct afs_cb_interest	*cb_interest;	/* Server on which this resides */
@@ -843,6 +851,7 @@ extern void afs_clear_permits(struct afs_vnode *);
 extern void afs_cache_permit(struct afs_vnode *, struct key *, unsigned int);
 extern void afs_zap_permits(struct rcu_head *);
 extern struct key *afs_request_key(struct afs_cell *);
+extern int afs_check_permit(struct afs_vnode *, struct key *, afs_access_t *);
 extern int afs_permission(struct inode *, int);
 extern void __exit afs_clean_up_permit_cache(void);
 

fs/afs/rotate.c

@@ -46,8 +46,7 @@ bool afs_begin_vnode_operation(struct afs_fs_cursor *fc, struct afs_vnode *vnode
 		return false;
 	}
 
-	if (test_bit(AFS_VNODE_READLOCKED, &vnode->flags) ||
-	    test_bit(AFS_VNODE_WRITELOCKED, &vnode->flags))
+	if (vnode->lock_state != AFS_VNODE_LOCK_NONE)
 		fc->flags |= AFS_FS_CURSOR_CUR_ONLY;
 	return true;
 }
@@ -117,7 +116,7 @@ static void afs_busy(struct afs_volume *volume, u32 abort_code)
 	case VSALVAGING:	m = "being salvaged";	break;
 	default:		m = "busy";		break;
 	}
-	
+
 	pr_notice("kAFS: Volume %u '%s' is %s\n", volume->vid, volume->name, m);
 }
 
@@ -438,24 +437,67 @@ bool afs_select_current_fileserver(struct afs_fs_cursor *fc)
 
 	_enter("");
 
-	if (!cbi) {
-		fc->ac.error = -ESTALE;
+	switch (fc->ac.error) {
+	case SHRT_MAX:
+		if (!cbi) {
+			fc->ac.error = -ESTALE;
+			fc->flags |= AFS_FS_CURSOR_STOP;
+			return false;
+		}
+
+		fc->cbi = afs_get_cb_interest(vnode->cb_interest);
+
+		read_lock(&cbi->server->fs_lock);
+		alist = rcu_dereference_protected(cbi->server->addresses,
+						  lockdep_is_held(&cbi->server->fs_lock));
+		afs_get_addrlist(alist);
+		read_unlock(&cbi->server->fs_lock);
+		if (!alist) {
+			fc->ac.error = -ESTALE;
+			fc->flags |= AFS_FS_CURSOR_STOP;
+			return false;
+		}
+
+		fc->ac.alist = alist;
+		fc->ac.addr  = NULL;
+		fc->ac.start = READ_ONCE(alist->index);
+		fc->ac.index = fc->ac.start;
+		fc->ac.error = 0;
+		fc->ac.begun = false;
+		goto iterate_address;
+
+	case 0:
+	default:
+		/* Success or local failure.  Stop. */
 		fc->flags |= AFS_FS_CURSOR_STOP;
+		_leave(" = f [okay/local %d]", fc->ac.error);
 		return false;
-	}
 
-	read_lock(&cbi->server->fs_lock);
-	alist = afs_get_addrlist(cbi->server->addresses);
-	read_unlock(&cbi->server->fs_lock);
-	if (!alist) {
-		fc->ac.error = -ESTALE;
+	case -ECONNABORTED:
 		fc->flags |= AFS_FS_CURSOR_STOP;
+		_leave(" = f [abort]");
 		return false;
+
+	case -ENETUNREACH:
+	case -EHOSTUNREACH:
+	case -ECONNREFUSED:
+	case -ETIMEDOUT:
+	case -ETIME:
+		_debug("no conn");
+		goto iterate_address;
 	}
 
-	fc->ac.alist = alist;
-	fc->ac.error = 0;
-	return true;
+iterate_address:
+	/* Iterate over the current server's address list to try and find an
+	 * address on which it will respond to us.
+	 */
+	if (afs_iterate_addresses(&fc->ac)) {
+		_leave(" = t");
+		return true;
+	}
+
+	afs_end_cursor(&fc->ac);
+	return false;
 }
 
 /*

fs/afs/security.c

@@ -284,8 +284,8 @@ void afs_cache_permit(struct afs_vnode *vnode, struct key *key,
  * permitted to be accessed with this authorisation, and if so, what access it
  * is granted
  */
-static int afs_check_permit(struct afs_vnode *vnode, struct key *key,
-			    afs_access_t *_access)
+int afs_check_permit(struct afs_vnode *vnode, struct key *key,
+		     afs_access_t *_access)
 {
 	struct afs_permits *permits;
 	bool valid = false;

fs/afs/server_list.c

@@ -17,7 +17,7 @@ void afs_put_serverlist(struct afs_net *net, struct afs_server_list *slist)
 {
 	int i;
 
-	if (refcount_dec_and_test(&slist->usage)) {
+	if (slist && refcount_dec_and_test(&slist->usage)) {
 		for (i = 0; i < slist->nr_servers; i++) {
 			afs_put_cb_interest(net, slist->servers[i].cb_interest);
 			afs_put_server(net, slist->servers[i].server);

fs/afs/write.c

@@ -119,6 +119,11 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 	}
 
 	if (f != t) {
+		if (PageWriteback(page)) {
+			trace_afs_page_dirty(vnode, tracepoint_string("alrdy"),
+					     page->index, priv);
+			goto flush_conflicting_write;
+		}
 		if (to < f || from > t)
 			goto flush_conflicting_write;
 		if (from < f)