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>

4 files changed, 20 insertions, 31 deletions

diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index 54f923792728..475f9c597cb7 100644
--- a/fs/autofs4/autofs_i.h
+++ b/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
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index bc482e07b925..450f529a4eae 100644
--- a/fs/autofs4/expire.c
+++ b/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;
 }
 
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index ebbfa0ce6d7b..96804a17bbd0 100644
--- a/fs/autofs4/root.c
+++ b/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);
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
index 56010056b2e6..25435987d6ae 100644
--- a/fs/autofs4/waitq.c
+++ b/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;