Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:38037 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753603AbcEIWEf (ORCPT ); Mon, 9 May 2016 18:04:35 -0400 From: Andreas Gruenbacher To: Alexander Viro Cc: Andreas Gruenbacher , Christoph Hellwig , "Theodore Ts'o" , Andreas Dilger , "J. Bruce Fields" , Jeff Layton , Trond Myklebust , Anna Schumaker , Dave Chinner , linux-ext4@vger.kernel.org, xfs@oss.sgi.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-api@vger.kernel.org Subject: [PATCH v21 13/22] vfs: Cache richacl in struct inode Date: Tue, 10 May 2016 00:02:46 +0200 Message-Id: <1462831375-23017-14-git-send-email-agruenba@redhat.com> In-Reply-To: <1462831375-23017-1-git-send-email-agruenba@redhat.com> References: <1462831375-23017-1-git-send-email-agruenba@redhat.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Cache richacls in struct inode so that this doesn't have to be done individually in each filesystem. This is similar to POSIX ACLs. Signed-off-by: Andreas Gruenbacher --- fs/inode.c | 13 +++++--- fs/richacl.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 5 ++- include/linux/richacl.h | 11 +++++++ 4 files changed, 105 insertions(+), 5 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index e937039..2d4e1ad 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -180,8 +180,11 @@ int inode_init_always(struct super_block *sb, struct inode *inode) inode->i_private = NULL; inode->i_mapping = mapping; INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */ -#ifdef CONFIG_FS_POSIX_ACL - inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; +#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL) + inode->i_acl = ACL_NOT_CACHED; +# if defined(CONFIG_FS_POSIX_ACL) + inode->i_default_acl = ACL_NOT_CACHED; +# endif #endif #ifdef CONFIG_FSNOTIFY @@ -237,17 +240,19 @@ void __destroy_inode(struct inode *inode) atomic_long_dec(&inode->i_sb->s_remove_count); } -#ifdef CONFIG_FS_POSIX_ACL +#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL) if (inode->i_acl && !is_uncached_acl(inode->i_acl)) base_acl_put(inode->i_acl); +# if defined(CONFIG_FS_POSIX_ACL) if (inode->i_default_acl && !is_uncached_acl(inode->i_default_acl)) base_acl_put(inode->i_default_acl); +# endif #endif this_cpu_dec(nr_inodes); } EXPORT_SYMBOL(__destroy_inode); -#ifdef CONFIG_FS_POSIX_ACL +#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL) struct base_acl *__get_cached_acl(struct base_acl **p) { struct base_acl *base_acl; diff --git a/fs/richacl.c b/fs/richacl.c index 8971ead..b2a03c1 100644 --- a/fs/richacl.c +++ b/fs/richacl.c @@ -20,6 +20,87 @@ #include #include +void set_cached_richacl(struct inode *inode, struct richacl *acl) +{ + struct base_acl *old; + + old = xchg(&inode->i_acl, &richacl_get(acl)->a_base); + if (!is_uncached_acl(old)) + base_acl_put(old); +} +EXPORT_SYMBOL_GPL(set_cached_richacl); + +void forget_cached_richacl(struct inode *inode) +{ + __forget_cached_acl(&inode->i_acl); +} +EXPORT_SYMBOL_GPL(forget_cached_richacl); + +struct richacl *get_richacl(struct inode *inode) +{ + struct base_acl *sentinel, *base_acl; + struct richacl *acl; + + if (!IS_RICHACL(inode)) + return NULL; + + /* + * The sentinel is used to detect when another operation like + * set_cached_richacl() or forget_cached_richacl() races with + * get_richacl(). + * It is guaranteed that is_uncached_acl(sentinel) is true. + */ + + base_acl = __get_cached_acl(&inode->i_acl); + if (!is_uncached_acl(base_acl)) + return richacl(base_acl); + + sentinel = uncached_acl_sentinel(current); + + /* + * If the ACL isn't being read yet, set our sentinel. Otherwise, the + * current value of the ACL will not be ACL_NOT_CACHED and so our own + * sentinel will not be set; another task will update the cache. We + * could wait for that other task to complete its job, but it's easier + * to just call ->get_acl to fetch the ACL ourself. (This is going to + * be an unlikely race.) + */ + if (cmpxchg(&inode->i_acl, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) + /* fall through */ ; + + /* + * Normally, the ACL returned by ->get_richacl will be cached. + * A filesystem can prevent that by calling + * forget_cached_richacl(inode) in ->get_richacl. + * + * If the filesystem doesn't have a ->get_richacl function at all, + * we'll just create the negative cache entry. + */ + if (!inode->i_op->get_richacl) { + set_cached_richacl(inode, NULL); + return NULL; + } + + acl = inode->i_op->get_richacl(inode); + if (IS_ERR(acl)) { + /* + * Remove our sentinel so that we don't block future attempts + * to cache the ACL. + */ + cmpxchg(&inode->i_acl, sentinel, ACL_NOT_CACHED); + return acl; + } + + /* + * Cache the result, but only if our sentinel is still in place. + */ + richacl_get(acl); + if (unlikely(cmpxchg(&inode->i_acl, sentinel, &acl->a_base) != sentinel)) + richacl_put(acl); + return acl; +} +EXPORT_SYMBOL_GPL(get_richacl); + /** * richacl_alloc - allocate a richacl * @count: number of entries diff --git a/include/linux/fs.h b/include/linux/fs.h index ec0bd11..8730825 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -588,6 +588,7 @@ struct base_acl { }; }; struct posix_acl; +struct richacl; #define ACL_NOT_CACHED ((void *)(-1)) static inline struct base_acl * @@ -618,9 +619,11 @@ struct inode { kgid_t i_gid; unsigned int i_flags; -#if defined(CONFIG_FS_POSIX_ACL) +#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL) struct base_acl *i_acl; +# if defined(CONFIG_FS_POSIX_ACL) struct base_acl *i_default_acl; +# endif #endif const struct inode_operations *i_op; diff --git a/include/linux/richacl.h b/include/linux/richacl.h index 35a5bcb..3e05c94 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -70,6 +70,17 @@ richacl_put(struct richacl *acl) base_acl_put(&acl->a_base); } +static inline struct richacl * +richacl(struct base_acl *base_acl) +{ + BUILD_BUG_ON(offsetof(struct richacl, a_base) != 0); + return container_of(base_acl, struct richacl, a_base); +} + +extern void set_cached_richacl(struct inode *, struct richacl *); +extern void forget_cached_richacl(struct inode *); +extern struct richacl *get_richacl(struct inode *); + /** * richace_is_owner - check if @ace is an OWNER@ entry */ -- 2.5.5