Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:40795 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753566AbcEIWEV (ORCPT ); Mon, 9 May 2016 18:04:21 -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, Andreas Dilger Subject: [PATCH v21 11/22] vfs: Cache base_acl objects in inodes Date: Tue, 10 May 2016 00:02:44 +0200 Message-Id: <1462831375-23017-12-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: POSIX ACLs and richacls are both objects allocated by kmalloc() with a reference count which are freed by kfree_rcu(). An inode can either cache an access and a default POSIX ACL, or a richacl (richacls do not have default acls). To allow an inode to cache either of the two kinds of acls, introduce a new base_acl type and convert i_acl and i_default_acl to that type. In most cases, the vfs then doesn't care which kind of acl an inode caches (if any). Signed-off-by: Andreas Gruenbacher Cc: Andreas Dilger --- drivers/staging/lustre/lustre/llite/llite_lib.c | 2 +- fs/9p/acl.c | 8 +-- fs/f2fs/acl.c | 4 +- fs/inode.c | 32 +++++++++++- fs/jffs2/acl.c | 6 ++- fs/namei.c | 33 ++++++------ fs/nfs/nfs3acl.c | 14 ++--- fs/posix_acl.c | 69 +++++++------------------ fs/richacl.c | 4 +- include/linux/fs.h | 41 +++++++++++++-- include/linux/posix_acl.h | 21 ++++---- include/linux/richacl.h | 9 ++-- 12 files changed, 139 insertions(+), 104 deletions(-) diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c index 6d6bb33..6084093 100644 --- a/drivers/staging/lustre/lustre/llite/llite_lib.c +++ b/drivers/staging/lustre/lustre/llite/llite_lib.c @@ -1074,7 +1074,7 @@ void ll_clear_inode(struct inode *inode) } #ifdef CONFIG_FS_POSIX_ACL else if (lli->lli_posix_acl) { - LASSERT(atomic_read(&lli->lli_posix_acl->a_refcount) == 1); + LASSERT(base_acl_refcount(&lli->lli_posix_acl->a_base) == 1); LASSERT(!lli->lli_remote_perms); posix_acl_release(lli->lli_posix_acl); lli->lli_posix_acl = NULL; diff --git a/fs/9p/acl.c b/fs/9p/acl.c index 2d94e94..8bf700f 100644 --- a/fs/9p/acl.c +++ b/fs/9p/acl.c @@ -87,14 +87,14 @@ int v9fs_get_acl(struct inode *inode, struct p9_fid *fid) static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type) { - struct posix_acl *acl; + struct base_acl *base_acl; /* * 9p Always cache the acl value when * instantiating the inode (v9fs_inode_from_fid) */ - acl = get_cached_acl(inode, type); - BUG_ON(is_uncached_acl(acl)); - return acl; + base_acl = get_cached_acl(inode, type); + BUG_ON(is_uncached_acl(base_acl)); + return posix_acl(base_acl); } struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type) diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c index 6f1fdda..cd40777 100644 --- a/fs/f2fs/acl.c +++ b/fs/f2fs/acl.c @@ -267,7 +267,7 @@ static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl, sizeof(struct posix_acl_entry); clone = kmemdup(acl, size, flags); if (clone) - atomic_set(&clone->a_refcount, 1); + base_acl_init(&clone->a_base); } return clone; } @@ -279,7 +279,7 @@ static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p) umode_t mode = *mode_p; int not_equiv = 0; - /* assert(atomic_read(acl->a_refcount) == 1); */ + /* assert(base_acl_refcount(&acl->a_base) == 1); */ FOREACH_ACL_ENTRY(pa, acl, pe) { switch(pa->e_tag) { diff --git a/fs/inode.c b/fs/inode.c index 4202aac..e937039 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -239,14 +239,42 @@ void __destroy_inode(struct inode *inode) #ifdef CONFIG_FS_POSIX_ACL if (inode->i_acl && !is_uncached_acl(inode->i_acl)) - posix_acl_release(inode->i_acl); + base_acl_put(inode->i_acl); if (inode->i_default_acl && !is_uncached_acl(inode->i_default_acl)) - posix_acl_release(inode->i_default_acl); + base_acl_put(inode->i_default_acl); #endif this_cpu_dec(nr_inodes); } EXPORT_SYMBOL(__destroy_inode); +#ifdef CONFIG_FS_POSIX_ACL +struct base_acl *__get_cached_acl(struct base_acl **p) +{ + struct base_acl *base_acl; + + for (;;) { + rcu_read_lock(); + base_acl = rcu_dereference(*p); + if (!base_acl || is_uncached_acl(base_acl) || + atomic_inc_not_zero(&base_acl->ba_refcount)) + break; + rcu_read_unlock(); + cpu_relax(); + } + rcu_read_unlock(); + return base_acl; +} + +void __forget_cached_acl(struct base_acl **p) +{ + struct base_acl *old; + + old = xchg(p, ACL_NOT_CACHED); + if (!is_uncached_acl(old)) + base_acl_put(old); +} +#endif + static void i_callback(struct rcu_head *head) { struct inode *inode = container_of(head, struct inode, i_rcu); diff --git a/fs/jffs2/acl.c b/fs/jffs2/acl.c index bc2693d..6c11909 100644 --- a/fs/jffs2/acl.c +++ b/fs/jffs2/acl.c @@ -292,13 +292,15 @@ int jffs2_init_acl_post(struct inode *inode) int rc; if (inode->i_default_acl) { - rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl); + rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, + posix_acl(inode->i_default_acl)); if (rc) return rc; } if (inode->i_acl) { - rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl); + rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, + posix_acl(inode->i_acl)); if (rc) return rc; } diff --git a/fs/namei.c b/fs/namei.c index 858ed96..2b1bf71 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -258,25 +258,28 @@ void putname(struct filename *name) static int check_acl(struct inode *inode, int mask) { #ifdef CONFIG_FS_POSIX_ACL - struct posix_acl *acl; - if (mask & MAY_NOT_BLOCK) { - acl = get_cached_acl_rcu(inode, ACL_TYPE_ACCESS); - if (!acl) + struct base_acl *base_acl; + + base_acl = rcu_dereference(inode->i_acl); + if (!base_acl) return -EAGAIN; /* no ->get_acl() calls in RCU mode... */ - if (is_uncached_acl(acl)) + if (is_uncached_acl(base_acl)) return -ECHILD; - return posix_acl_permission(inode, acl, mask & ~MAY_NOT_BLOCK); - } - - acl = get_acl(inode, ACL_TYPE_ACCESS); - if (IS_ERR(acl)) - return PTR_ERR(acl); - if (acl) { - int error = posix_acl_permission(inode, acl, mask); - posix_acl_release(acl); - return error; + return posix_acl_permission(inode, posix_acl(base_acl), + mask & ~MAY_NOT_BLOCK); + } else { + struct posix_acl *acl; + + acl = get_acl(inode, ACL_TYPE_ACCESS); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl) { + int error = posix_acl_permission(inode, acl, mask); + posix_acl_release(acl); + return error; + } } #endif diff --git a/fs/nfs/nfs3acl.c b/fs/nfs/nfs3acl.c index 720d92f5..2b70944 100644 --- a/fs/nfs/nfs3acl.c +++ b/fs/nfs/nfs3acl.c @@ -16,28 +16,28 @@ * caching get_acl results in a race-free way. See fs/posix_acl.c:get_acl() * for explanations. */ -static void nfs3_prepare_get_acl(struct posix_acl **p) +static void nfs3_prepare_get_acl(struct base_acl **p) { - struct posix_acl *sentinel = uncached_acl_sentinel(current); + struct base_acl *sentinel = uncached_acl_sentinel(current); if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) { /* Not the first reader or sentinel already in place. */ } } -static void nfs3_complete_get_acl(struct posix_acl **p, struct posix_acl *acl) +static void nfs3_complete_get_acl(struct base_acl **p, struct posix_acl *acl) { - struct posix_acl *sentinel = uncached_acl_sentinel(current); + struct base_acl *sentinel = uncached_acl_sentinel(current); /* Only cache the ACL if our sentinel is still in place. */ posix_acl_dup(acl); - if (cmpxchg(p, sentinel, acl) != sentinel) + if (cmpxchg(p, sentinel, &acl->a_base) != sentinel) posix_acl_release(acl); } -static void nfs3_abort_get_acl(struct posix_acl **p) +static void nfs3_abort_get_acl(struct base_acl **p) { - struct posix_acl *sentinel = uncached_acl_sentinel(current); + struct base_acl *sentinel = uncached_acl_sentinel(current); /* Remove our sentinel upon failure. */ cmpxchg(p, sentinel, ACL_NOT_CACHED); diff --git a/fs/posix_acl.c b/fs/posix_acl.c index db1fb0f..e202e79 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -21,7 +21,7 @@ #include #include -static struct posix_acl **acl_by_type(struct inode *inode, int type) +static inline struct base_acl **acl_by_type(struct inode *inode, int type) { switch (type) { case ACL_TYPE_ACCESS: @@ -33,51 +33,23 @@ static struct posix_acl **acl_by_type(struct inode *inode, int type) } } -struct posix_acl *get_cached_acl(struct inode *inode, int type) +struct base_acl *get_cached_acl(struct inode *inode, int type) { - struct posix_acl **p = acl_by_type(inode, type); - struct posix_acl *acl; - - for (;;) { - rcu_read_lock(); - acl = rcu_dereference(*p); - if (!acl || is_uncached_acl(acl) || - atomic_inc_not_zero(&acl->a_refcount)) - break; - rcu_read_unlock(); - cpu_relax(); - } - rcu_read_unlock(); - return acl; + return __get_cached_acl(acl_by_type(inode, type)); } EXPORT_SYMBOL(get_cached_acl); -struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) -{ - return rcu_dereference(*acl_by_type(inode, type)); -} -EXPORT_SYMBOL(get_cached_acl_rcu); - void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl) { - struct posix_acl **p = acl_by_type(inode, type); - struct posix_acl *old; + struct base_acl **p = acl_by_type(inode, type); + struct base_acl *old; - old = xchg(p, posix_acl_dup(acl)); + old = xchg(p, &posix_acl_dup(acl)->a_base); if (!is_uncached_acl(old)) - posix_acl_release(old); + base_acl_put(old); } EXPORT_SYMBOL(set_cached_acl); -static void __forget_cached_acl(struct posix_acl **p) -{ - struct posix_acl *old; - - old = xchg(p, ACL_NOT_CACHED); - if (!is_uncached_acl(old)) - posix_acl_release(old); -} - void forget_cached_acl(struct inode *inode, int type) { __forget_cached_acl(acl_by_type(inode, type)); @@ -93,25 +65,24 @@ EXPORT_SYMBOL(forget_all_cached_acls); struct posix_acl *get_acl(struct inode *inode, int type) { - void *sentinel; - struct posix_acl **p; + struct base_acl **p = acl_by_type(inode, type); + struct base_acl *sentinel, *base_acl; struct posix_acl *acl; + if (!IS_POSIXACL(inode)) + return NULL; + /* * The sentinel is used to detect when another operation like * set_cached_acl() or forget_cached_acl() races with get_acl(). * It is guaranteed that is_uncached_acl(sentinel) is true. */ - acl = get_cached_acl(inode, type); - if (!is_uncached_acl(acl)) - return acl; - - if (!IS_POSIXACL(inode)) - return NULL; + base_acl = __get_cached_acl(p); + if (!is_uncached_acl(base_acl)) + return posix_acl(base_acl); sentinel = uncached_acl_sentinel(current); - p = acl_by_type(inode, type); /* * If the ACL isn't being read yet, set our sentinel. Otherwise, the @@ -151,7 +122,7 @@ struct posix_acl *get_acl(struct inode *inode, int type) * Cache the result, but only if our sentinel is still in place. */ posix_acl_dup(acl); - if (unlikely(cmpxchg(p, sentinel, acl) != sentinel)) + if (unlikely(cmpxchg(p, sentinel, &acl->a_base) != sentinel)) posix_acl_release(acl); return acl; } @@ -163,7 +134,7 @@ EXPORT_SYMBOL(get_acl); void posix_acl_init(struct posix_acl *acl, int count) { - atomic_set(&acl->a_refcount, 1); + base_acl_init(&acl->a_base); acl->a_count = count; } EXPORT_SYMBOL(posix_acl_init); @@ -196,7 +167,7 @@ posix_acl_clone(const struct posix_acl *acl, gfp_t flags) sizeof(struct posix_acl_entry); clone = kmemdup(acl, size, flags); if (clone) - atomic_set(&clone->a_refcount, 1); + base_acl_init(&clone->a_base); } return clone; } @@ -418,7 +389,7 @@ static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p) umode_t mode = *mode_p; int not_equiv = 0; - /* assert(atomic_read(acl->a_refcount) == 1); */ + /* assert(base_acl_refcount(&acl->a_base) == 1); */ FOREACH_ACL_ENTRY(pa, acl, pe) { switch(pa->e_tag) { @@ -473,7 +444,7 @@ static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode) struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; struct posix_acl_entry *pa, *pe; - /* assert(atomic_read(acl->a_refcount) == 1); */ + /* assert(base_acl_refcount(&acl->a_base) == 1); */ FOREACH_ACL_ENTRY(pa, acl, pe) { switch(pa->e_tag) { diff --git a/fs/richacl.c b/fs/richacl.c index cb0ef3f..8971ead 100644 --- a/fs/richacl.c +++ b/fs/richacl.c @@ -31,7 +31,7 @@ richacl_alloc(int count, gfp_t gfp) struct richacl *acl = kzalloc(size, gfp); if (acl) { - atomic_set(&acl->a_refcount, 1); + base_acl_init(&acl->a_base); acl->a_count = count; } return acl; @@ -50,7 +50,7 @@ richacl_clone(const struct richacl *acl, gfp_t gfp) if (dup) { memcpy(dup, acl, size); - atomic_set(&dup->a_refcount, 1); + base_acl_init(&dup->a_base); } return dup; } diff --git a/include/linux/fs.h b/include/linux/fs.h index 16d2380..c569117 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -581,17 +581,23 @@ static inline void mapping_allow_writable(struct address_space *mapping) #define i_size_ordered_init(inode) do { } while (0) #endif +struct base_acl { + union { + atomic_t ba_refcount; + struct rcu_head ba_rcu; + }; +}; struct posix_acl; #define ACL_NOT_CACHED ((void *)(-1)) -static inline struct posix_acl * +static inline struct base_acl * uncached_acl_sentinel(struct task_struct *task) { return (void *)task + 1; } static inline bool -is_uncached_acl(struct posix_acl *acl) +is_uncached_acl(struct base_acl *acl) { return (long)acl & 1; } @@ -612,9 +618,9 @@ struct inode { kgid_t i_gid; unsigned int i_flags; -#ifdef CONFIG_FS_POSIX_ACL - struct posix_acl *i_acl; - struct posix_acl *i_default_acl; +#if defined(CONFIG_FS_POSIX_ACL) + struct base_acl *i_acl; + struct base_acl *i_default_acl; #endif const struct inode_operations *i_op; @@ -3128,4 +3134,29 @@ static inline bool dir_relax(struct inode *inode) extern bool path_noexec(const struct path *path); extern void inode_nohighmem(struct inode *inode); +static inline void base_acl_get(struct base_acl *acl) +{ + if (acl) + atomic_inc(&acl->ba_refcount); +} + +static inline void base_acl_put(struct base_acl *acl) +{ + if (acl && atomic_dec_and_test(&acl->ba_refcount)) + kfree_rcu(acl, ba_rcu); +} + +static inline void base_acl_init(struct base_acl *acl) +{ + atomic_set(&acl->ba_refcount, 1); +} + +static inline int base_acl_refcount(struct base_acl *acl) +{ + return atomic_read(&acl->ba_refcount); +} + +extern struct base_acl *__get_cached_acl(struct base_acl **); +extern void __forget_cached_acl(struct base_acl **); + #endif /* _LINUX_FS_H */ diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h index 5b5a80c..daf84fa 100644 --- a/include/linux/posix_acl.h +++ b/include/linux/posix_acl.h @@ -43,10 +43,7 @@ struct posix_acl_entry { }; struct posix_acl { - union { - atomic_t a_refcount; - struct rcu_head a_rcu; - }; + struct base_acl a_base; /* must be first, see posix_acl_release() */ unsigned int a_count; struct posix_acl_entry a_entries[0]; }; @@ -61,8 +58,7 @@ struct posix_acl { static inline struct posix_acl * posix_acl_dup(struct posix_acl *acl) { - if (acl) - atomic_inc(&acl->a_refcount); + base_acl_get(&acl->a_base); return acl; } @@ -72,10 +68,16 @@ posix_acl_dup(struct posix_acl *acl) static inline void posix_acl_release(struct posix_acl *acl) { - if (acl && atomic_dec_and_test(&acl->a_refcount)) - kfree_rcu(acl, a_rcu); + BUILD_BUG_ON(offsetof(struct posix_acl, a_base) != 0); + base_acl_put(&acl->a_base); } +static inline struct posix_acl * +posix_acl(struct base_acl *base_acl) +{ + BUILD_BUG_ON(offsetof(struct posix_acl, a_base) != 0); + return container_of(base_acl, struct posix_acl, a_base); +} /* posix_acl.c */ @@ -99,8 +101,7 @@ extern int posix_acl_create(struct inode *, umode_t *, struct posix_acl **, extern int simple_set_acl(struct inode *, struct posix_acl *, int); extern int simple_acl_create(struct inode *, struct inode *); -struct posix_acl *get_cached_acl(struct inode *inode, int type); -struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type); +struct base_acl *get_cached_acl(struct inode *inode, int type); void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl); void forget_cached_acl(struct inode *inode, int type); void forget_all_cached_acls(struct inode *inode); diff --git a/include/linux/richacl.h b/include/linux/richacl.h index be9fb65..35a5bcb 100644 --- a/include/linux/richacl.h +++ b/include/linux/richacl.h @@ -31,7 +31,7 @@ struct richace { }; struct richacl { - atomic_t a_refcount; + struct base_acl a_base; /* must be first, see richacl_put() */ unsigned int a_owner_mask; unsigned int a_group_mask; unsigned int a_other_mask; @@ -56,8 +56,7 @@ struct richacl { static inline struct richacl * richacl_get(struct richacl *acl) { - if (acl) - atomic_inc(&acl->a_refcount); + base_acl_get(&acl->a_base); return acl; } @@ -67,8 +66,8 @@ richacl_get(struct richacl *acl) static inline void richacl_put(struct richacl *acl) { - if (acl && atomic_dec_and_test(&acl->a_refcount)) - kfree(acl); + BUILD_BUG_ON(offsetof(struct richacl, a_base) != 0); + base_acl_put(&acl->a_base); } /** -- 2.5.5