[PATCH] bdev: fix ->bd_part_count leak

[powerpc.git] / fs / block_dev.c

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 36c38f4..f3c3a44 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -900,7 +900,11 @@ 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 __blkdev_put(struct block_device *bdev, int for_part);
+
+static int do_open(struct block_device *bdev, struct file *file, int for_part)
 {
        struct module *owner = NULL;
        struct gendisk *disk;
@@ -917,7 +921,7 @@ static int do_open(struct block_device *bdev, struct file *file)
        }
        owner = disk->fops->owner;
 
-       mutex_lock(&bdev->bd_mutex);
+       mutex_lock_nested(&bdev->bd_mutex, for_part);
        if (!bdev->bd_openers) {
                bdev->bd_disk = disk;
                bdev->bd_contains = bdev;
@@ -944,25 +948,21 @@ 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 +975,11 @@ 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;
@@ -990,7 +988,7 @@ out_first:
        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);
+               __blkdev_put(bdev->bd_contains, 1);
        bdev->bd_contains = NULL;
        put_disk(disk);
        module_put(owner);
@@ -1002,7 +1000,8 @@ 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 +1016,13 @@ 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 +1042,7 @@ 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 +1056,18 @@ 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);
+       mutex_lock_nested(&bdev->bd_mutex, for_part);
        lock_kernel();
+       if (for_part)
+               bdev->bd_part_count--;
+
        if (!--bdev->bd_openers) {
                sync_blockdev(bdev);
                kill_bdev(bdev);
@@ -1068,10 +1075,6 @@ 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 +1088,22 @@ 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)