Re: [External] Re: [PATCH V3 6/6] erofs: Support sharing cookies in the same domain
From: Jia Zhu
Date: Thu Sep 15 2022 - 03:27:22 EST
在 2022/9/15 14:53, JeffleXu 写道:
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.
Thanks.
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.
Thanks for catching this. I'll fix it in next version.
+
+ 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;
This code style is more intuitive, I'll revise it, thanks.
+ }
> 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 {