autofs4 - remove autofs4_lock

The autofs4_lock introduced by the rcu-walk changes has unnecessarily
broad scope. The locking is better handled by the per-autofs super
block lookup_lock.

Signed-off-by: Ian Kent <raven@themaw.net>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/autofs4/autofs_i.h

@@ -61,8 +61,6 @@ do {							\
 		current->pid, __func__, ##args);	\
 } while (0)
 
-extern spinlock_t autofs4_lock;
-
 /* Unified info structure.  This is pointed to by both the dentry and
    inode structures.  Each file in the filesystem has an instance of this
    structure.  It holds a reference to the dentry, so dentries are never

fs/autofs4/expire.c

@@ -92,10 +92,11 @@ done:
 static struct dentry *get_next_positive_subdir(struct dentry *prev,
 						struct dentry *root)
 {
+	struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
 	struct list_head *next;
 	struct dentry *p, *q;
 
-	spin_lock(&autofs4_lock);
+	spin_lock(&sbi->lookup_lock);
 
 	if (prev == NULL) {
 		spin_lock(&root->d_lock);
@@ -112,7 +113,7 @@ again:
 start:
 	if (next == &root->d_subdirs) {
 		spin_unlock(&p->d_lock);
-		spin_unlock(&autofs4_lock);
+		spin_unlock(&sbi->lookup_lock);
 		dput(prev);
 		return NULL;
 	}
@@ -129,7 +130,7 @@ start:
 	dget_dlock(q);
 	spin_unlock(&q->d_lock);
 	spin_unlock(&p->d_lock);
-	spin_unlock(&autofs4_lock);
+	spin_unlock(&sbi->lookup_lock);
 
 	dput(prev);
 
@@ -142,13 +143,14 @@ start:
 static struct dentry *get_next_positive_dentry(struct dentry *prev,
 						struct dentry *root)
 {
+	struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
 	struct list_head *next;
 	struct dentry *p, *ret;
 
 	if (prev == NULL)
 		return dget(root);
 
-	spin_lock(&autofs4_lock);
+	spin_lock(&sbi->lookup_lock);
 relock:
 	p = prev;
 	spin_lock(&p->d_lock);
@@ -160,7 +162,7 @@ again:
 
 			if (p == root) {
 				spin_unlock(&p->d_lock);
-				spin_unlock(&autofs4_lock);
+				spin_unlock(&sbi->lookup_lock);
 				dput(prev);
 				return NULL;
 			}
@@ -190,7 +192,7 @@ again:
 	dget_dlock(ret);
 	spin_unlock(&ret->d_lock);
 	spin_unlock(&p->d_lock);
-	spin_unlock(&autofs4_lock);
+	spin_unlock(&sbi->lookup_lock);
 
 	dput(prev);
 
@@ -459,13 +461,13 @@ found:
 	ino->flags |= AUTOFS_INF_EXPIRING;
 	init_completion(&ino->expire_complete);
 	spin_unlock(&sbi->fs_lock);
-	spin_lock(&autofs4_lock);
+	spin_lock(&sbi->lookup_lock);
 	spin_lock(&expired->d_parent->d_lock);
 	spin_lock_nested(&expired->d_lock, DENTRY_D_LOCK_NESTED);
 	list_move(&expired->d_parent->d_subdirs, &expired->d_u.d_child);
 	spin_unlock(&expired->d_lock);
 	spin_unlock(&expired->d_parent->d_lock);
-	spin_unlock(&autofs4_lock);
+	spin_unlock(&sbi->lookup_lock);
 	return expired;
 }
 

fs/autofs4/root.c

@@ -23,8 +23,6 @@
 
 #include "autofs_i.h"
 
-DEFINE_SPINLOCK(autofs4_lock);
-
 static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
 static int autofs4_dir_unlink(struct inode *,struct dentry *);
 static int autofs4_dir_rmdir(struct inode *,struct dentry *);
@@ -125,15 +123,15 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
 	 * autofs file system so just let the libfs routines handle
 	 * it.
 	 */
-	spin_lock(&autofs4_lock);
+	spin_lock(&sbi->lookup_lock);
 	spin_lock(&dentry->d_lock);
 	if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
 		spin_unlock(&dentry->d_lock);
-		spin_unlock(&autofs4_lock);
+		spin_unlock(&sbi->lookup_lock);
 		return -ENOENT;
 	}
 	spin_unlock(&dentry->d_lock);
-	spin_unlock(&autofs4_lock);
+	spin_unlock(&sbi->lookup_lock);
 
 out:
 	return dcache_dir_open(inode, file);
@@ -171,7 +169,6 @@ static struct dentry *autofs4_lookup_active(struct dentry *dentry)
 	const unsigned char *str = name->name;
 	struct list_head *p, *head;
 
-	spin_lock(&autofs4_lock);
 	spin_lock(&sbi->lookup_lock);
 	head = &sbi->active_list;
 	list_for_each(p, head) {
@@ -204,14 +201,12 @@ static struct dentry *autofs4_lookup_active(struct dentry *dentry)
 			dget_dlock(active);
 			spin_unlock(&active->d_lock);
 			spin_unlock(&sbi->lookup_lock);
-			spin_unlock(&autofs4_lock);
 			return active;
 		}
 next:
 		spin_unlock(&active->d_lock);
 	}
 	spin_unlock(&sbi->lookup_lock);
-	spin_unlock(&autofs4_lock);
 
 	return NULL;
 }
@@ -226,7 +221,6 @@ static struct dentry *autofs4_lookup_expiring(struct dentry *dentry)
 	const unsigned char *str = name->name;
 	struct list_head *p, *head;
 
-	spin_lock(&autofs4_lock);
 	spin_lock(&sbi->lookup_lock);
 	head = &sbi->expiring_list;
 	list_for_each(p, head) {
@@ -259,14 +253,12 @@ static struct dentry *autofs4_lookup_expiring(struct dentry *dentry)
 			dget_dlock(expiring);
 			spin_unlock(&expiring->d_lock);
 			spin_unlock(&sbi->lookup_lock);
-			spin_unlock(&autofs4_lock);
 			return expiring;
 		}
 next:
 		spin_unlock(&expiring->d_lock);
 	}
 	spin_unlock(&sbi->lookup_lock);
-	spin_unlock(&autofs4_lock);
 
 	return NULL;
 }
@@ -603,12 +595,12 @@ static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
 
 	dir->i_mtime = CURRENT_TIME;
 
-	spin_lock(&autofs4_lock);
-	autofs4_add_expiring(dentry);
+	spin_lock(&sbi->lookup_lock);
+	__autofs4_add_expiring(dentry);
 	spin_lock(&dentry->d_lock);
 	__d_drop(dentry);
 	spin_unlock(&dentry->d_lock);
-	spin_unlock(&autofs4_lock);
+	spin_unlock(&sbi->lookup_lock);
 
 	return 0;
 }
@@ -677,20 +669,17 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
 	if (!autofs4_oz_mode(sbi))
 		return -EACCES;
 
-	spin_lock(&autofs4_lock);
 	spin_lock(&sbi->lookup_lock);
 	spin_lock(&dentry->d_lock);
 	if (!list_empty(&dentry->d_subdirs)) {
 		spin_unlock(&dentry->d_lock);
 		spin_unlock(&sbi->lookup_lock);
-		spin_unlock(&autofs4_lock);
 		return -ENOTEMPTY;
 	}
 	__autofs4_add_expiring(dentry);
-	spin_unlock(&sbi->lookup_lock);
 	__d_drop(dentry);
 	spin_unlock(&dentry->d_lock);
-	spin_unlock(&autofs4_lock);
+	spin_unlock(&sbi->lookup_lock);
 
 	if (sbi->version < 5)
 		autofs_clear_leaf_automount_flags(dentry);

fs/autofs4/waitq.c

@@ -197,12 +197,12 @@ rename_retry:
 
 	seq = read_seqbegin(&rename_lock);
 	rcu_read_lock();
-	spin_lock(&autofs4_lock);
+	spin_lock(&sbi->fs_lock);
 	for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
 		len += tmp->d_name.len + 1;
 
 	if (!len || --len > NAME_MAX) {
-		spin_unlock(&autofs4_lock);
+		spin_unlock(&sbi->fs_lock);
 		rcu_read_unlock();
 		if (read_seqretry(&rename_lock, seq))
 			goto rename_retry;
@@ -218,7 +218,7 @@ rename_retry:
 		p -= tmp->d_name.len;
 		strncpy(p, tmp->d_name.name, tmp->d_name.len);
 	}
-	spin_unlock(&autofs4_lock);
+	spin_unlock(&sbi->fs_lock);
 	rcu_read_unlock();
 	if (read_seqretry(&rename_lock, seq))
 		goto rename_retry;