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]>
---
fs/erofs/super.c | 48 ++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 42 insertions(+), 6 deletions(-)
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index a5e4de60a0d8..292b4a70ce19 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -398,6 +398,7 @@ enum {
Opt_dax,
Opt_dax_enum,
Opt_device,
+ Opt_fsid,
Opt_err
};
@@ -422,6 +423,7 @@ 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),
{}
};
@@ -517,6 +519,16 @@ 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;
}
@@ -597,9 +609,14 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_op = &erofs_sops;
- if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
- erofs_err(sb, "failed to set erofs blksize");
- return -EINVAL;
+ if (erofs_is_fscache_mode(sb)) {
+ sb->s_blocksize = EROFS_BLKSIZ;
+ sb->s_blocksize_bits = LOG_BLOCK_SIZE;
+ } else {
+ if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
+ erofs_err(sb, "failed to set erofs blksize");
+ return -EINVAL;
+ }
}
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
@@ -608,7 +625,7 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
sb->s_fs_info = sbi;
sbi->opt = ctx->opt;
- sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev, &sbi->dax_part_off);
+ ctx->opt.fsid = NULL;
sbi->devs = ctx->devs;
ctx->devs = NULL;
@@ -625,6 +642,8 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
err = super_setup_bdi(sb);
if (err)
return err;
+ } else {
+ sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev, &sbi->dax_part_off);
}
err = erofs_read_superblock(sb);
@@ -684,6 +703,11 @@ 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);
}
@@ -733,6 +757,7 @@ 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);
}
@@ -773,7 +798,10 @@ 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)
@@ -783,6 +811,7 @@ 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;
}
@@ -884,7 +913,10 @@ static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
struct erofs_sb_info *sbi = EROFS_SB(sb);
- u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
+ u64 id = 0;
+
+ if (!erofs_is_fscache_mode(sb))
+ id = huge_encode_dev(sb->s_bdev->bd_dev);
buf->f_type = sb->s_magic;
buf->f_bsize = EROFS_BLKSIZ;
@@ -929,6 +961,10 @@ 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;
}
--
2.27.0