On 9/14/22 6:50 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 | 89 +++++++++++++++++++++++++++++++++++++++++++--
> fs/erofs/internal.h | 4 +-
> 2 files changed, 89 insertions(+), 4 deletions(-)
>
> diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
> index 4e0a441afb7d..e9ae1ee963e2 100644
> --- a/fs/erofs/fscache.c
> +++ b/fs/erofs/fscache.c
> @@ -7,6 +7,7 @@
> #include "internal.h"
>
> static DEFINE_MUTEX(erofs_domain_list_lock);
> +static DEFINE_MUTEX(erofs_domain_cookies_lock);
> static LIST_HEAD(erofs_domain_list);
> static struct vfsmount *erofs_pseudo_mnt;
>
> @@ -504,7 +505,6 @@ static int erofs_fscache_init_domain(struct super_block *sb)
>
> domain->volume = sbi->volume;
> refcount_set(&domain->ref, 1);
> - mutex_init(&domain->mutex);
This needs to be folded into patch 4.
> list_add(&domain->list, &erofs_domain_list);
> return 0;
> out:
> @@ -534,8 +534,8 @@ static int erofs_fscache_register_domain(struct super_block *sb)
> return err;
> }
>
> -struct erofs_fscache *erofs_fscache_register_cookie(struct super_block *sb,
> - char *name, bool need_inode)
> +struct erofs_fscache *erofs_fscache_acquire_cookie(struct super_block *sb,
> + char *name, bool need_inode)
> {
> struct fscache_volume *volume = EROFS_SB(sb)->volume;
> struct erofs_fscache *ctx;
> @@ -585,13 +585,96 @@ struct erofs_fscache *erofs_fscache_register_cookie(struct super_block *sb,
> return ERR_PTR(ret);
> }
>
> +static
> +struct erofs_fscache *erofs_fscache_domain_init_cookie(struct super_block *sb,
> + char *name, bool need_inode)
> +{
> + struct inode *inode;
> + struct erofs_fscache *ctx;
> + struct erofs_sb_info *sbi = EROFS_SB(sb);
> + struct erofs_domain *domain = sbi->domain;
> +
> + ctx = erofs_fscache_acquire_cookie(sb, name, need_inode);
> + if (IS_ERR(ctx))
> + return ctx;
> +
> + ctx->name = kstrdup(name, GFP_KERNEL);
> + if (!ctx->name)
> + return ERR_PTR(-ENOMEM);
The previously registered erofs_fscache needs to be cleaned up in the
error path.
> +
> + inode = new_inode(erofs_pseudo_mnt->mnt_sb);
> + if (!inode) {
> + kfree(ctx->name);
> + return ERR_PTR(-ENOMEM);
> + }
Ditto.
> +
> + ctx->domain = domain;
> + ctx->anon_inode = inode;
> + inode->i_private = ctx;
> + erofs_fscache_domain_get(domain);
> + return ctx;
> +}
> +
> +static
> +struct erofs_fscache *erofs_domain_register_cookie(struct super_block *sb,
> + char *name, bool need_inode)
> +{
> + 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(&erofs_domain_cookies_lock);
> + list_for_each_entry(inode, &psb->s_inodes, i_sb_list) {
> + ctx = inode->i_private;
> + if (!ctx)
> + continue;
> + if (ctx->domain == domain && !strcmp(ctx->name, name)) {
> + igrab(inode);
> + mutex_unlock(&erofs_domain_cookies_lock);
> + return ctx;
> + }
> + }
> + ctx = erofs_fscache_domain_init_cookie(sb, name, need_inode);
> + mutex_unlock(&erofs_domain_cookies_lock);
> + return ctx;
> +}
> +
> +struct erofs_fscache *erofs_fscache_register_cookie(struct super_block *sb,
> + char *name, bool need_inode)
> +{
> + struct erofs_sb_info *sbi = EROFS_SB(sb);
> +
> + if (sbi->opt.domain_id)
> + return erofs_domain_register_cookie(sb, name, need_inode);
> + else
> + return erofs_fscache_acquire_cookie(sb, name, need_inode);
> +}
> +
> void erofs_fscache_unregister_cookie(struct erofs_fscache *ctx)
> {
> + struct erofs_domain *domain;
> +
> if (!ctx)
> return;
> + domain = ctx->domain;
> + if (domain) {
> + mutex_lock(&erofs_domain_cookies_lock);
> + /* Cookie is still in use */
> + if (atomic_read(&ctx->anon_inode->i_count) > 1) {
> + iput(ctx->anon_inode);
> + mutex_unlock(&erofs_domain_cookies_lock);
> + return;
> + }
> + iput(ctx->anon_inode);
> + kfree(ctx->name);
> + mutex_unlock(&erofs_domain_cookies_lock);
mutex_lock(&erofs_domain_cookies_lock);
drop = atomic_read(&ctx->anon_inode->i_count) == 1;
iput(ctx->anon_inode);
mutex_unlock(&erofs_domain_cookies_lock);
if (!drop)
return;
> + }
> > fscache_unuse_cookie(ctx->cookie, NULL, NULL);
> fscache_relinquish_cookie(ctx->cookie, false);
> + erofs_fscache_domain_put(domain);
> ctx->cookie = NULL;
fscache_unuse_cookie(ctx->cookie, NULL, NULL);
fscache_relinquish_cookie(ctx->cookie, false);
erofs_fscache_domain_put(domain);
kfree(ctx->name);
>
> iput(ctx->inode);
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 4dd0b545755a..8a6f94b27a23 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -101,7 +101,6 @@ struct erofs_sb_lz4_info {
>
> struct erofs_domain {
> refcount_t ref;
> - struct mutex mutex;
> struct list_head list;
> struct fscache_volume *volume;
> char *domain_id;
> @@ -110,6 +109,9 @@ struct erofs_domain {
> struct erofs_fscache {
> struct fscache_cookie *cookie;
> struct inode *inode;
> + struct inode *anon_inode;
> + struct erofs_domain *domain;
> + char *name;
> };
>
> struct erofs_sb_info {
--
Thanks,
Jingbo
