Re: [PATCH 7/9] fs: add a method to shut down the file system

Jan Kara
2023-05-08T13:01:42Z

On Fri 05-05-23 13:51:30, Christoph Hellwig wrote:
> Add a new ->shutdown super operation that can be used to tell the file
> system to shut down, and call it from newly created holder ops when the
> block device under a file system shuts down.
>
> This only covers the main block device for "simple" file systems using
> get_tree_bdev / mount_bdev. File systems their own get_tree method
> or opening additional devices will need to set up their own
> blk_holder_ops.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> fs/super.c | 21 +++++++++++++++++++--
> include/linux/fs.h | 1 +
> 2 files changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/fs/super.c b/fs/super.c
> index 012ce140080375..f127589700ab25 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -1206,6 +1206,22 @@ int get_tree_keyed(struct fs_context *fc,
> EXPORT_SYMBOL(get_tree_keyed);
>
> #ifdef CONFIG_BLOCK
> +static void fs_mark_dead(struct block_device *bdev)
> +{
> + struct super_block *sb;
> +
> + sb = get_super(bdev);
> + if (!sb)
> + return;
> +
> + if (sb->s_op->shutdown)
> + sb->s_op->shutdown(sb);
> + drop_super(sb);
> +}
> +
> +static const struct blk_holder_ops fs_holder_ops = {
> + .mark_dead = fs_mark_dead,
> +};
>
> static int set_bdev_super(struct super_block *s, void *data)
> {
> @@ -1248,7 +1264,8 @@ int get_tree_bdev(struct fs_context *fc,
> if (!fc->source)
> return invalf(fc, "No source specified");
>
> - bdev = blkdev_get_by_path(fc->source, mode, fc->fs_type, NULL);
> + bdev = blkdev_get_by_path(fc->source, mode, fc->fs_type,
> + &fs_holder_ops);
> if (IS_ERR(bdev)) {
> errorf(fc, "%s: Can't open blockdev", fc->source);
> return PTR_ERR(bdev);
> @@ -1333,7 +1350,7 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
> if (!(flags & SB_RDONLY))
> mode |= FMODE_WRITE;
>
> - bdev = blkdev_get_by_path(dev_name, mode, fs_type, NULL);
> + bdev = blkdev_get_by_path(dev_name, mode, fs_type, &fs_holder_ops);
> if (IS_ERR(bdev))
> return ERR_CAST(bdev);
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 21a98168085641..cf3042641b9b30 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1932,6 +1932,7 @@ struct super_operations {
> struct shrink_control *);
> long (*free_cached_objects)(struct super_block *,
> struct shrink_control *);
> + void (*shutdown)(struct super_block *sb);
> };
>
> /*
> --
> 2.39.2
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR