Commit 9c0cc9c7 authored by Jeffle Xu's avatar Jeffle Xu Committed by Gao Xiang
Browse files

erofs: add 'fsid' mount option 



Introduce 'fsid' mount option to enable on-demand read sementics, in
which case, erofs will be mounted from data blobs. Users could specify
the name of primary data blob by this mount option.

Signed-off-by: default avatarJeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220425122143.56815-22-jefflexu@linux.alibaba.com


Acked-by: default avatarChao Yu <chao@kernel.org>
Tested-by: default avatarZichen Tian <tianzichen@kuaishou.com>
Tested-by: default avatarJia Zhu <zhujia.zj@bytedance.com>
Tested-by: default avatarYan Song <yansong.ys@antgroup.com>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent c665b394

fs/erofs/super.c

+30 −1
Original line number Diff line number Diff line
@@ -372,6 +372,8 @@ static int erofs_read_superblock(struct super_block *sb) 


	if (erofs_sb_has_ztailpacking(sbi))

		erofs_info(sb, "EXPERIMENTAL compressed inline data feature in use. Use at your own risk!");

	if (erofs_is_fscache_mode(sb))

		erofs_info(sb, "EXPERIMENTAL fscache-based on-demand read feature in use. Use at your own risk!");

out:

	erofs_put_metabuf(&buf);

	return ret;
@@ -400,6 +402,7 @@ enum { 
	Opt_dax,

	Opt_dax_enum,

	Opt_device,

	Opt_fsid,

	Opt_err

};
@@ -424,6 +427,7 @@ static const struct fs_parameter_spec erofs_fs_parameters[] = { 
	fsparam_flag("dax",             Opt_dax),

	fsparam_enum("dax",		Opt_dax_enum, erofs_dax_param_enums),

	fsparam_string("device",	Opt_device),

	fsparam_string("fsid",		Opt_fsid),

	{}

};
@@ -519,6 +523,16 @@ static int erofs_fc_parse_param(struct fs_context *fc, 
		}

		++ctx->devs->extra_devices;

		break;

	case Opt_fsid:

#ifdef CONFIG_EROFS_FS_ONDEMAND

		kfree(ctx->opt.fsid);

		ctx->opt.fsid = kstrdup(param->string, GFP_KERNEL);

		if (!ctx->opt.fsid)

			return -ENOMEM;

#else

		errorfc(fc, "fsid option not supported");

#endif

		break;

	default:

		return -ENOPARAM;

	}
@@ -643,6 +657,7 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) 


	sb->s_fs_info = sbi;

	sbi->opt = ctx->opt;

	ctx->opt.fsid = NULL;

	sbi->devs = ctx->devs;

	ctx->devs = NULL;
@@ -730,6 +745,11 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc) 


static int erofs_fc_get_tree(struct fs_context *fc)

{

	struct erofs_fs_context *ctx = fc->fs_private;



	if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && ctx->opt.fsid)

		return get_tree_nodev(fc, erofs_fc_fill_super);



	return get_tree_bdev(fc, erofs_fc_fill_super);

}
@@ -779,6 +799,7 @@ static void erofs_fc_free(struct fs_context *fc) 
	struct erofs_fs_context *ctx = fc->fs_private;



	erofs_free_dev_context(ctx->devs);

	kfree(ctx->opt.fsid);

	kfree(ctx);

}
@@ -819,6 +840,9 @@ static void erofs_kill_sb(struct super_block *sb) 


	WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);



	if (erofs_is_fscache_mode(sb))

		generic_shutdown_super(sb);

	else

		kill_block_super(sb);



	sbi = EROFS_SB(sb);
@@ -829,6 +853,7 @@ static void erofs_kill_sb(struct super_block *sb) 
	fs_put_dax(sbi->dax_dev);

	erofs_fscache_unregister_cookie(&sbi->s_fscache);

	erofs_fscache_unregister_fs(sb);

	kfree(sbi->opt.fsid);

	kfree(sbi);

	sb->s_fs_info = NULL;

}
@@ -978,6 +1003,10 @@ static int erofs_show_options(struct seq_file *seq, struct dentry *root) 
		seq_puts(seq, ",dax=always");

	if (test_opt(opt, DAX_NEVER))

		seq_puts(seq, ",dax=never");

#ifdef CONFIG_EROFS_FS_ONDEMAND

	if (opt->fsid)

		seq_printf(seq, ",fsid=%s", opt->fsid);

#endif

	return 0;

}

fs/erofs/sysfs.c

+2 −2
Original line number Diff line number Diff line
@@ -205,8 +205,8 @@ int erofs_register_sysfs(struct super_block *sb) 


	sbi->s_kobj.kset = &erofs_root;

	init_completion(&sbi->s_kobj_unregister);

	err = kobject_init_and_add(&sbi->s_kobj, &erofs_sb_ktype, NULL,

				   "%s", sb->s_id);

	err = kobject_init_and_add(&sbi->s_kobj, &erofs_sb_ktype, NULL, "%s",

			erofs_is_fscache_mode(sb) ? sbi->opt.fsid : sb->s_id);

	if (err)

		goto put_sb_kobj;

	return 0;