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 <[email protected]> --- fs/erofs/fscache.c | 90 ++++++++++++++++++++++++++++++++++++++++++++- fs/erofs/internal.h | 3 ++ 2 files changed, 91 insertions(+), 2 deletions(-) diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c index ff8382df493e..8873a093cf7b 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; @@ -527,8 +528,8 @@ 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; @@ -577,14 +578,99 @@ 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) +{ + int err; + struct inode *inode; + struct erofs_fscache *ctx; + struct erofs_domain *domain = EROFS_SB(sb)->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) { + err = -ENOMEM; + goto out; + } + + inode = new_inode(erofs_pseudo_mnt->mnt_sb); + if (!inode) { + kfree(ctx->name); + err = -ENOMEM; + goto out; + } + + ctx->domain = domain; + ctx->anon_inode = inode; + inode->i_private = ctx; + refcount_inc(&domain->ref); + return ctx; +out: + fscache_unuse_cookie(ctx->cookie, NULL, NULL); + fscache_relinquish_cookie(ctx->cookie, false); + if (need_inode) + iput(ctx->inode); + kfree(ctx); + return ERR_PTR(err); +} + +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_domain *domain = EROFS_SB(sb)->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 || ctx->domain != domain || strcmp(ctx->name, name)) + continue; + 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) +{ + if (EROFS_SB(sb)->opt.domain_id) + return erofs_domain_register_cookie(sb, name, need_inode); + return erofs_fscache_acquire_cookie(sb, name, need_inode); +} + void erofs_fscache_unregister_cookie(struct erofs_fscache *ctx) { + bool drop; + struct erofs_domain *domain; + if (!ctx) return; + domain = ctx->domain; + if (domain) { + 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); iput(ctx->inode); + kfree(ctx->name); kfree(ctx); } diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h index 88c1a46867b3..8a6f94b27a23 100644 --- a/fs/erofs/internal.h +++ b/fs/erofs/internal.h @@ -109,6 +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 { -- 2.20.1
