1 files changed, 29 insertions, 22 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 36c38f48a4ed..19f5f153ddb8 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -900,7 +900,10 @@ void bd_set_size(struct block_device *bdev, loff_t size)
 }
 EXPORT_SYMBOL(bd_set_size);
 
-static int do_open(struct block_device *bdev, struct file *file)
+static int __blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags,
+                        int for_part);
+
+static int do_open(struct block_device *bdev, struct file *file, int for_part)
 {
         struct module *owner = NULL;
         struct gendisk *disk;
@@ -944,25 +947,21 @@ static int do_open(struct block_device *bdev, struct file *file)
                         ret = -ENOMEM;
                         if (!whole)
                                 goto out_first;
-                        ret = blkdev_get(whole, file->f_mode, file->f_flags);
+                        BUG_ON(for_part);
+                        ret = __blkdev_get(whole, file->f_mode, file->f_flags, 1);
                         if (ret)
                                 goto out_first;
                         bdev->bd_contains = whole;
-                        mutex_lock(&whole->bd_mutex);
-                        whole->bd_part_count++;
                         p = disk->part[part - 1];
                         bdev->bd_inode->i_data.backing_dev_info =
                            whole->bd_inode->i_data.backing_dev_info;
                         if (!(disk->flags & GENHD_FL_UP) || !p || !p->nr_sects) {
-                                whole->bd_part_count--;
-                                mutex_unlock(&whole->bd_mutex);
                                 ret = -ENXIO;
                                 goto out_first;
                         }
                         kobject_get(&p->kobj);
                         bdev->bd_part = p;
                         bd_set_size(bdev, (loff_t) p->nr_sects << 9);
-                        mutex_unlock(&whole->bd_mutex);
                 }
         } else {
                 put_disk(disk);
@@ -975,13 +974,11 @@ static int do_open(struct block_device *bdev, struct file *file)
                         }
                         if (bdev->bd_invalidated)
                                 rescan_partitions(bdev->bd_disk, bdev);
-                } else {
-                        mutex_lock(&bdev->bd_contains->bd_mutex);
-                        bdev->bd_contains->bd_part_count++;
-                        mutex_unlock(&bdev->bd_contains->bd_mutex);
                 }
         }
         bdev->bd_openers++;
+        if (for_part)
+                bdev->bd_part_count++;
         mutex_unlock(&bdev->bd_mutex);
         unlock_kernel();
         return 0;
@@ -1002,7 +999,8 @@ out:
         return ret;
 }
 
-int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags)
+static int __blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags,
+                        int for_part)
 {
         /*
          * This crockload is due to bad choice of ->open() type.
@@ -1017,9 +1015,13 @@ int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags)
         fake_file.f_dentry = &fake_dentry;
         fake_dentry.d_inode = bdev->bd_inode;
 
-        return do_open(bdev, &fake_file);
+        return do_open(bdev, &fake_file, for_part);
 }
 
+int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags)
+{
+        return __blkdev_get(bdev, mode, flags, 0);
+}
 EXPORT_SYMBOL(blkdev_get);
 
 static int blkdev_open(struct inode * inode, struct file * filp)
@@ -1039,7 +1041,7 @@ static int blkdev_open(struct inode * inode, struct file * filp)
         if (bdev == NULL)
                 return -ENOMEM;
 
-        res = do_open(bdev, filp);
+        res = do_open(bdev, filp, 0);
         if (res)
                 return res;
 
@@ -1053,14 +1055,18 @@ static int blkdev_open(struct inode * inode, struct file * filp)
         return res;
 }
 
-int blkdev_put(struct block_device *bdev)
+static int __blkdev_put(struct block_device *bdev, int for_part)
 {
         int ret = 0;
         struct inode *bd_inode = bdev->bd_inode;
         struct gendisk *disk = bdev->bd_disk;
+        struct block_device *victim = NULL;
 
         mutex_lock(&bdev->bd_mutex);
         lock_kernel();
+        if (for_part)
+                bdev->bd_part_count--;
+
         if (!--bdev->bd_openers) {
                 sync_blockdev(bdev);
                 kill_bdev(bdev);
@@ -1068,10 +1074,6 @@ int blkdev_put(struct block_device *bdev)
         if (bdev->bd_contains == bdev) {
                 if (disk->fops->release)
                         ret = disk->fops->release(bd_inode, NULL);
-        } else {
-                mutex_lock(&bdev->bd_contains->bd_mutex);
-                bdev->bd_contains->bd_part_count--;
-                mutex_unlock(&bdev->bd_contains->bd_mutex);
         }
         if (!bdev->bd_openers) {
                 struct module *owner = disk->fops->owner;
@@ -1085,17 +1087,22 @@ int blkdev_put(struct block_device *bdev)
                 }
                 bdev->bd_disk = NULL;
                 bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
-                if (bdev != bdev->bd_contains) {
-                        blkdev_put(bdev->bd_contains);
-                }
+                if (bdev != bdev->bd_contains)
+                        victim = bdev->bd_contains;
                 bdev->bd_contains = NULL;
         }
         unlock_kernel();
         mutex_unlock(&bdev->bd_mutex);
         bdput(bdev);
+        if (victim)
+                __blkdev_put(victim, 1);
         return ret;
 }
 
+int blkdev_put(struct block_device *bdev)
+{
+        return __blkdev_put(bdev, 0);
+}
 EXPORT_SYMBOL(blkdev_put);
 
 static int blkdev_close(struct inode * inode, struct file * filp)