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Commit 14238819 authored by Anand Jain's avatar Anand Jain Committed by Chris Mason
Browse files

btrfs: do not background blkdev_put() 



At the end of unmount/dev-delete, if the device exclusive open is not
actually closed, then there might be a race with another program in
the userland who is trying to open the device in exclusive mode and
it may fail for eg:
      unmount /btrfs; fsck /dev/x
      btrfs dev del /dev/x /btrfs; fsck /dev/x
so here background blkdev_put() is not a choice

Signed-off-by: default avatarAnand Jain <Anand.Jain@oracle.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 28b737f6

fs/btrfs/volumes.c

+19 −8
Original line number Diff line number Diff line
@@ -834,10 +834,6 @@ static void __free_device(struct work_struct *work) 
	struct btrfs_device *device;



	device = container_of(work, struct btrfs_device, rcu_work);



	if (device->bdev)

		blkdev_put(device->bdev, device->mode);



	rcu_string_free(device->name);

	kfree(device);

}
@@ -852,6 +848,17 @@ static void free_device(struct rcu_head *head) 
	schedule_work(&device->rcu_work);

}



static void btrfs_close_bdev(struct btrfs_device *device)

{

	if (device->bdev && device->writeable) {

		sync_blockdev(device->bdev);

		invalidate_bdev(device->bdev);

	}



	if (device->bdev)

		blkdev_put(device->bdev, device->mode);

}



static void btrfs_close_one_device(struct btrfs_device *device)

{

	struct btrfs_fs_devices *fs_devices = device->fs_devices;
@@ -870,10 +877,7 @@ static void btrfs_close_one_device(struct btrfs_device *device) 
	if (device->missing)

		fs_devices->missing_devices--;



	if (device->bdev && device->writeable) {

		sync_blockdev(device->bdev);

		invalidate_bdev(device->bdev);

	}

	btrfs_close_bdev(device);



	new_device = btrfs_alloc_device(NULL, &device->devid,

					device->uuid);
@@ -1932,6 +1936,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid) 
		btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);

	}



	btrfs_close_bdev(device);



	call_rcu(&device->rcu, free_device);



	num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
@@ -2025,6 +2031,9 @@ void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info, 
		/* zero out the old super if it is writable */

		btrfs_scratch_superblocks(srcdev->bdev, srcdev->name->str);

	}



	btrfs_close_bdev(srcdev);



	call_rcu(&srcdev->rcu, free_device);



	/*
@@ -2080,6 +2089,8 @@ void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info, 
	 * the device_list_mutex lock.

	 */

	btrfs_scratch_superblocks(tgtdev->bdev, tgtdev->name->str);



	btrfs_close_bdev(tgtdev);

	call_rcu(&tgtdev->rcu, free_device);

}