NFSv4: Fix lookup revalidate of regular files

[sfrench/cifs-2.6.git] / fs / super.c

diff --git a/fs/super.c b/fs/super.c
index 7429588d6b4922574f05d43cbfbc6b5ad01ab648..f3a8c008e16430be1ba08d9f575c1df9faeb0f0a 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -981,58 +981,42 @@ void emergency_thaw_all(void)
        }
 }
 
-/*
- * Unnamed block devices are dummy devices used by virtual
- * filesystems which don't use real block-devices.  -- jrs
- */
-
 static DEFINE_IDA(unnamed_dev_ida);
-static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
-/* Many userspace utilities consider an FSID of 0 invalid.
- * Always return at least 1 from get_anon_bdev.
- */
-static int unnamed_dev_start = 1;
 
+/**
+ * get_anon_bdev - Allocate a block device for filesystems which don't have one.
+ * @p: Pointer to a dev_t.
+ *
+ * Filesystems which don't use real block devices can call this function
+ * to allocate a virtual block device.
+ *
+ * Context: Any context.  Frequently called while holding sb_lock.
+ * Return: 0 on success, -EMFILE if there are no anonymous bdevs left
+ * or -ENOMEM if memory allocation failed.
+ */
 int get_anon_bdev(dev_t *p)
 {
        int dev;
-       int error;
 
- retry:
-       if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0)
-               return -ENOMEM;
-       spin_lock(&unnamed_dev_lock);
-       error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev);
-       if (!error)
-               unnamed_dev_start = dev + 1;
-       spin_unlock(&unnamed_dev_lock);
-       if (error == -EAGAIN)
-               /* We raced and lost with another CPU. */
-               goto retry;
-       else if (error)
-               return -EAGAIN;
-
-       if (dev >= (1 << MINORBITS)) {
-               spin_lock(&unnamed_dev_lock);
-               ida_remove(&unnamed_dev_ida, dev);
-               if (unnamed_dev_start > dev)
-                       unnamed_dev_start = dev;
-               spin_unlock(&unnamed_dev_lock);
-               return -EMFILE;
-       }
-       *p = MKDEV(0, dev & MINORMASK);
+       /*
+        * Many userspace utilities consider an FSID of 0 invalid.
+        * Always return at least 1 from get_anon_bdev.
+        */
+       dev = ida_alloc_range(&unnamed_dev_ida, 1, (1 << MINORBITS) - 1,
+                       GFP_ATOMIC);
+       if (dev == -ENOSPC)
+               dev = -EMFILE;
+       if (dev < 0)
+               return dev;
+
+       *p = MKDEV(0, dev);
        return 0;
 }
 EXPORT_SYMBOL(get_anon_bdev);
 
 void free_anon_bdev(dev_t dev)
 {
-       int slot = MINOR(dev);
-       spin_lock(&unnamed_dev_lock);
-       ida_remove(&unnamed_dev_ida, slot);
-       if (slot < unnamed_dev_start)
-               unnamed_dev_start = slot;
-       spin_unlock(&unnamed_dev_lock);
+       ida_free(&unnamed_dev_ida, MINOR(dev));
 }
 EXPORT_SYMBOL(free_anon_bdev);
 
@@ -1040,7 +1024,6 @@ int set_anon_super(struct super_block *s, void *data)
 {
        return get_anon_bdev(&s->s_dev);
 }
-
 EXPORT_SYMBOL(set_anon_super);
 
 void kill_anon_super(struct super_block *sb)
@@ -1049,7 +1032,6 @@ void kill_anon_super(struct super_block *sb)
        generic_shutdown_super(sb);
        free_anon_bdev(dev);
 }
-
 EXPORT_SYMBOL(kill_anon_super);
 
 void kill_litter_super(struct super_block *sb)
@@ -1058,7 +1040,6 @@ void kill_litter_super(struct super_block *sb)
                d_genocide(sb->s_root);
        kill_anon_super(sb);
 }
-
 EXPORT_SYMBOL(kill_litter_super);
 
 static int ns_test_super(struct super_block *sb, void *data)