On 9/2/22 6:53 PM, Jia Zhu wrote:
> Several erofs filesystems can belong to one domain, and data blobs can
> be shared among these erofs filesystems of same domain.
>
> Users could specify domain_id mount option to create or join into a domain.
>
> Signed-off-by: Jia Zhu <zhujia.zj@xxxxxxxxxxxxx>
> ---
> fs/erofs/fscache.c | 73 +++++++++++++++++++++++++++++++++++++++++++++
> fs/erofs/internal.h | 12 ++++++++
> fs/erofs/super.c | 10 +++++--
> 3 files changed, 93 insertions(+), 2 deletions(-)
>
> diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
> index 439dd3cc096a..c01845808ede 100644
> --- a/fs/erofs/fscache.c
> +++ b/fs/erofs/fscache.c
> @@ -559,12 +559,27 @@ int erofs_fscache_register_cookie(struct super_block *sb,
> void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache)
> {
> struct erofs_fscache *ctx = *fscache;
> + struct erofs_domain *domain;
>
> if (!ctx)
> return;
> + domain = ctx->domain;
> + if (domain) {
> + mutex_lock(&domain->mutex);
> + /* Cookie is still in use */
> + if (atomic_read(&ctx->anon_inode->i_count) > 1) {
> + iput(ctx->anon_inode);
> + mutex_unlock(&domain->mutex);
> + return;
> + }
> + iput(ctx->anon_inode);
> + kfree(ctx->name);
> + mutex_unlock(&domain->mutex);
> + }
>
> fscache_unuse_cookie(ctx->cookie, NULL, NULL);
> fscache_relinquish_cookie(ctx->cookie, false);
> + erofs_fscache_domain_put(domain);
> ctx->cookie = NULL;
>
> iput(ctx->inode);
> @@ -609,3 +624,61 @@ void erofs_fscache_unregister_fs(struct super_block *sb)
> sbi->volume = NULL;
> sbi->domain = NULL;
> }
> +
> +static int erofs_fscache_domain_init_cookie(struct super_block *sb,
> + struct erofs_fscache **fscache, char *name, bool need_inode)
> +{
> + int ret;
> + struct inode *inode;
> + struct erofs_fscache *ctx;
> + struct erofs_sb_info *sbi = EROFS_SB(sb);
> + struct erofs_domain *domain = sbi->domain;
> +
> + ret = erofs_fscache_register_cookie(sb, &ctx, name, need_inode);
> + if (ret)
> + return ret;
> +
> + ctx->name = kstrdup(name, GFP_KERNEL);
> + if (!ctx->name)
> + return -ENOMEM;
Shall we clean up the above registered cookie in the error path?
> +
> + inode = new_inode(erofs_pseudo_mnt->mnt_sb);
> + if (!inode) {
> + kfree(ctx->name);
> + return -ENOMEM;
> + }
Ditto.
> +
> + ctx->domain = domain;
> + ctx->anon_inode = inode;
> + inode->i_private = ctx;
> + erofs_fscache_domain_get(domain);
> + *fscache = ctx;
> + return 0;
> +}
> +
> +int erofs_domain_register_cookie(struct super_block *sb,
> + struct erofs_fscache **fscache, char *name, bool need_inode)
> +{
> + int err;
> + struct inode *inode;
> + struct erofs_fscache *ctx;
> + struct erofs_sb_info *sbi = EROFS_SB(sb);
> + struct erofs_domain *domain = sbi->domain;
> + struct super_block *psb = erofs_pseudo_mnt->mnt_sb;
> +
> + mutex_lock(&domain->mutex);
What is domain->mutex used for?
> + list_for_each_entry(inode, &psb->s_inodes, i_sb_list) {
> + ctx = inode->i_private;
> + if (!ctx)
> + continue;
> + if (!strcmp(ctx->name, name)) {
> + *fscache = ctx;
> + igrab(inode);
> + mutex_unlock(&domain->mutex);
> + return 0;
> + }
> + }
> + err = erofs_fscache_domain_init_cookie(sb, fscache, name, need_inode);
> + mutex_unlock(&domain->mutex);
> + return err;
> +}
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 2790c93ffb83..efa4f4ad77cc 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -110,6 +110,9 @@ struct erofs_domain {
> struct erofs_fscache {
> struct fscache_cookie *cookie;
> struct inode *inode;
> + struct inode *anon_inode;
Why can't we reuse @inode for anon_inode?
> + struct erofs_domain *domain;
> + char *name;
> };
>
> struct erofs_sb_info {
> @@ -625,6 +628,9 @@ int erofs_fscache_register_domain(struct super_block *sb);
> int erofs_fscache_register_cookie(struct super_block *sb,
> struct erofs_fscache **fscache,
> char *name, bool need_inode);
> +int erofs_domain_register_cookie(struct super_block *sb,
> + struct erofs_fscache **fscache,
> + char *name, bool need_inode);
> void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache);
>
> extern const struct address_space_operations erofs_fscache_access_aops;
> @@ -646,6 +652,12 @@ static inline int erofs_fscache_register_cookie(struct super_block *sb,
> {
> return -EOPNOTSUPP;
> }
> +static inline int erofs_domain_register_cookie(struct super_block *sb,
> + struct erofs_fscache **fscache,
> + char *name, bool need_inode)
> +{
> + return -EOPNOTSUPP;
> +}
>
> static inline void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache)
> {
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 667a78f0ee70..11c5ba84567c 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -245,8 +245,12 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
> }
>
> if (erofs_is_fscache_mode(sb)) {
> - ret = erofs_fscache_register_cookie(sb, &dif->fscache,
> - dif->path, false);
> + if (sbi->opt.domain_id)
> + ret = erofs_domain_register_cookie(sb, &dif->fscache, dif->path,
> + false);
> + else
> + ret = erofs_fscache_register_cookie(sb, &dif->fscache, dif->path,
> + false);
> if (ret)
> return ret;
> } else {
> @@ -726,6 +730,8 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
> err = erofs_fscache_register_domain(sb);
> if (err)
> return err;
> + err = erofs_domain_register_cookie(sb, &sbi->s_fscache,
> + sbi->opt.fsid, true);
> } else {
> err = erofs_fscache_register_fs(sb);
> if (err)
--
Thanks,
Jingbo
