On 9/14/22 6:50 PM, Jia Zhu wrote:
> Introduce 'domain_id' mount option to enable shared domain sementics.
> In which case, the related cookie is shared if two mountpoints in the
> same domain have the same data blob. Users could specify the name of
> domain by this mount option.
>
> Signed-off-by: Jia Zhu <zhujia.zj@xxxxxxxxxxxxx>
Could you please move this patch to the end of this patch set, so that
once the "domain_id" mount option is visible to users, this feature
really works?
> ---
> fs/erofs/internal.h | 1 +
> fs/erofs/super.c | 17 +++++++++++++++++
> fs/erofs/sysfs.c | 19 +++++++++++++++++--
> 3 files changed, 35 insertions(+), 2 deletions(-)
>
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index aa71eb65e965..2d129c6b3027 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -76,6 +76,7 @@ struct erofs_mount_opts {
> #endif
> unsigned int mount_opt;
> char *fsid;
> + char *domain_id;
> };
Indeed we can add @domain_id field into struct erofs_mount_opts in prep
for the following implementation of the domain_id feature. IOW, the
above change can be folded into patch 4, just like what [1] does.
[1]
https://github.com/torvalds/linux/commit/c6be2bd0a5dd91f98d6b5d2df2c79bc32993352c#diff-eee5fb30f4e83505af808386e84c953266d2fd2e76b6e66cb94cf6e849881240R77
>
> struct erofs_dev_context {
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 7aa57dcebf31..856758ee4869 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -440,6 +440,7 @@ enum {
> Opt_dax_enum,
> Opt_device,
> Opt_fsid,
> + Opt_domain_id,
> Opt_err
> };
>
> @@ -465,6 +466,7 @@ static const struct fs_parameter_spec erofs_fs_parameters[] = {
> fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
> fsparam_string("device", Opt_device),
> fsparam_string("fsid", Opt_fsid),
> + fsparam_string("domain_id", Opt_domain_id),
> {}
> };
>
> @@ -568,6 +570,16 @@ static int erofs_fc_parse_param(struct fs_context *fc,
> return -ENOMEM;
> #else
> errorfc(fc, "fsid option not supported");
> +#endif
> + break;
> + case Opt_domain_id:
> +#ifdef CONFIG_EROFS_FS_ONDEMAND
> + kfree(ctx->opt.domain_id);
> + ctx->opt.domain_id = kstrdup(param->string, GFP_KERNEL);
> + if (!ctx->opt.domain_id)
> + return -ENOMEM;
> +#else
> + errorfc(fc, "domain_id option not supported");
> #endif
> break;
> default:
> @@ -695,6 +707,7 @@ 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;
> + ctx->opt.domain_id = NULL;
> sbi->devs = ctx->devs;
> ctx->devs = NULL;
>
> @@ -834,6 +847,7 @@ static void erofs_fc_free(struct fs_context *fc)
>
> erofs_free_dev_context(ctx->devs);
> kfree(ctx->opt.fsid);
> + kfree(ctx->opt.domain_id);
> kfree(ctx);
> }
>
> @@ -887,6 +901,7 @@ static void erofs_kill_sb(struct super_block *sb)
> fs_put_dax(sbi->dax_dev, NULL);
> erofs_fscache_unregister_fs(sb);
> kfree(sbi->opt.fsid);
> + kfree(sbi->opt.domain_id);
> kfree(sbi);
> sb->s_fs_info = NULL;
> }
> @@ -1040,6 +1055,8 @@ static int erofs_show_options(struct seq_file *seq, struct dentry *root)
> #ifdef CONFIG_EROFS_FS_ONDEMAND
> if (opt->fsid)
> seq_printf(seq, ",fsid=%s", opt->fsid);
> + if (opt->domain_id)
> + seq_printf(seq, ",domain_id=%s", opt->domain_id);
> #endif
> return 0;
> }
> diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c
> index c1383e508bbe..341fb43ad587 100644
> --- a/fs/erofs/sysfs.c
> +++ b/fs/erofs/sysfs.c
> @@ -201,12 +201,27 @@ static struct kobject erofs_feat = {
> int erofs_register_sysfs(struct super_block *sb)
> {
> struct erofs_sb_info *sbi = EROFS_SB(sb);
> + char *name;
> + char *str = NULL;
> int err;
>
> + if (erofs_is_fscache_mode(sb)) {
> + if (sbi->opt.domain_id) {
> + str = kasprintf(GFP_KERNEL, "%s,%s", sbi->opt.domain_id,
> + sbi->opt.fsid);
> + if (!str)
> + return -ENOMEM;
> + name = str;
> + } else {
> + name = sbi->opt.fsid;
> + }
> + } else {
> + name = sb->s_id;
> + }
> 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",
> - erofs_is_fscache_mode(sb) ? sbi->opt.fsid : sb->s_id);
> + err = kobject_init_and_add(&sbi->s_kobj, &erofs_sb_ktype, NULL, "%s", name);
> + kfree(str);
> if (err)
> goto put_sb_kobj;
> return 0;
--
Thanks,
Jingbo
