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: Jeffle Xu <[email protected]>
Reviewed-by: Gao Xiang <[email protected]>
Tested-by: Zichen Tian <[email protected]>
Tested-by: Jia Zhu <[email protected]>
---
fs/erofs/super.c | 31 ++++++++++++++++++++++++++++++-
fs/erofs/sysfs.c | 4 ++--
2 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index f68ba929100d..4a623630e1c4 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -371,6 +371,8 @@ 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;
@@ -399,6 +401,7 @@ enum {
Opt_dax,
Opt_dax_enum,
Opt_device,
+ Opt_fsid,
Opt_err
};
@@ -423,6 +426,7 @@ 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),
{}
};
@@ -518,6 +522,16 @@ 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;
}
@@ -604,6 +618,7 @@ 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;
@@ -690,6 +705,11 @@ 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);
}
@@ -739,6 +759,7 @@ 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);
}
@@ -779,7 +800,10 @@ static void erofs_kill_sb(struct super_block *sb)
WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
- kill_block_super(sb);
+ if (erofs_is_fscache_mode(sb))
+ generic_shutdown_super(sb);
+ else
+ kill_block_super(sb);
sbi = EROFS_SB(sb);
if (!sbi)
@@ -789,6 +813,7 @@ 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;
}
@@ -938,6 +963,10 @@ 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;
}
diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c
index f3babf1e6608..c1383e508bbe 100644
--- a/fs/erofs/sysfs.c
+++ b/fs/erofs/sysfs.c
@@ -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;
--
2.27.0