autofs4: use helper functions for active list handling

Define some simple helper functions for adding and deleting entries on the
active (and unhashed) dentry list.
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Sage Weil <sage@newdream.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Yehuda Saheh <yehuda@newdream.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/autofs4/autofs_i.h

@@ -75,6 +75,8 @@ struct autofs_info {
 	struct completion expire_complete;
 
 	struct list_head active;
+	int active_count;
+
 	struct list_head expiring;
 
 	struct autofs_sb_info *sbi;

fs/autofs4/inode.c

@@ -49,6 +49,7 @@ struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
 		ino->dentry = NULL;
 		ino->size = 0;
 		INIT_LIST_HEAD(&ino->active);
+		ino->active_count = 0;
 		INIT_LIST_HEAD(&ino->expiring);
 		atomic_set(&ino->count, 0);
 	}

fs/autofs4/root.c

@@ -72,6 +72,38 @@ const struct inode_operations autofs4_dir_inode_operations = {
 	.rmdir		= autofs4_dir_rmdir,
 };
 
+static void autofs4_add_active(struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+	if (ino) {
+		spin_lock(&sbi->lookup_lock);
+		if (!ino->active_count) {
+			if (list_empty(&ino->active))
+				list_add(&ino->active, &sbi->active_list);
+		}
+		ino->active_count++;
+		spin_unlock(&sbi->lookup_lock);
+	}
+	return;
+}
+
+static void autofs4_del_active(struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+	if (ino) {
+		spin_lock(&sbi->lookup_lock);
+		ino->active_count--;
+		if (!ino->active_count) {
+			if (!list_empty(&ino->active))
+				list_del_init(&ino->active);
+		}
+		spin_unlock(&sbi->lookup_lock);
+	}
+	return;
+}
+
 static int autofs4_dir_open(struct inode *inode, struct file *file)
 {
 	struct dentry *dentry = file->f_path.dentry;
@@ -513,9 +545,7 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
 		dentry->d_fsdata = ino;
 		ino->dentry = dentry;
 
-		spin_lock(&sbi->lookup_lock);
-		list_add(&ino->active, &sbi->active_list);
-		spin_unlock(&sbi->lookup_lock);
+		autofs4_add_active(dentry);
 
 		d_instantiate(dentry, NULL);
 	}
@@ -624,10 +654,7 @@ static int autofs4_dir_symlink(struct inode *dir,
 	if (!ino)
 		return -ENOMEM;
 
-	spin_lock(&sbi->lookup_lock);
-	if (!list_empty(&ino->active))
-		list_del_init(&ino->active);
-	spin_unlock(&sbi->lookup_lock);
+	autofs4_del_active(dentry);
 
 	ino->size = strlen(symname);
 	cp = kmalloc(ino->size + 1, GFP_KERNEL);
@@ -775,10 +802,7 @@ static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 	if (!ino)
 		return -ENOMEM;
 
-	spin_lock(&sbi->lookup_lock);
-	if (!list_empty(&ino->active))
-		list_del_init(&ino->active);
-	spin_unlock(&sbi->lookup_lock);
+	autofs4_del_active(dentry);
 
 	inode = autofs4_get_inode(dir->i_sb, ino);
 	if (!inode) {