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>

3 files changed, 38 insertions, 11 deletions

diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index 8f7cdde41733..f3cf151a59e3 100644
--- a/fs/autofs4/autofs_i.h
+++ b/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;
diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c
index 69c8142da838..4670a7818eac 100644
--- a/fs/autofs4/inode.c
+++ b/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);
         }
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index b96a3c57359d..67d8d962168d 100644
--- a/fs/autofs4/root.c
+++ b/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) {