From patchwork Wed Nov 16 15:17:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 13045398 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92270C4321E for ; Wed, 16 Nov 2022 15:17:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233561AbiKPPRe (ORCPT ); Wed, 16 Nov 2022 10:17:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233424AbiKPPRc (ORCPT ); Wed, 16 Nov 2022 10:17:32 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F4704FF8B; Wed, 16 Nov 2022 07:17:31 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id F2CE261E83; Wed, 16 Nov 2022 15:17:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9CA1EC433D7; Wed, 16 Nov 2022 15:17:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668611850; bh=p23e5m8DB+OKwKhVmD1O6yeNHkOhWzyyqsVD65vSeBI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p0HQqOExoOnjBN1V8PkV04km2Y9lGdedL8CkqrITCb/VFyvbRXCXPbPhoxgJqh/G1 /48k+c/B41BxHsbc4m9N98fSkWBzEu9Eq3LDsmEyZOREfTw1PHLV6VuV2r9YoLQvxH /QHAjsu/I0r/PCrF0Z5WnvjbZtlf5WPathtxXailBPUEOIiOZS1M3ehgVpZr79WoF7 +ZN39A23hWVkcul/OO2mOh6ghaIAniyZ0gwUjj8QsQmyD46cLMsB9C1HhKOIjMWYat biLuw5WRkfVzZBGk3FsVhTUwsAGSKtKCofKdO9VEMRnrteEcSLi5xnsINyUaymcWr3 SiL554x2Bg59A== From: Jeff Layton To: linux-fsdevel@vger.kernel.org Cc: linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-cifs@vger.kernel.org, chuck.lever@oracle.com, viro@zeniv.linux.org.uk, hch@lst.de Subject: [PATCH 1/7] filelock: add a new locks_inode_context accessor function Date: Wed, 16 Nov 2022 10:17:20 -0500 Message-Id: <20221116151726.129217-2-jlayton@kernel.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221116151726.129217-1-jlayton@kernel.org> References: <20221116151726.129217-1-jlayton@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org There are a number of places in the kernel that are accessing the inode->i_flctx field without smp_load_acquire. This is required to ensure that the caller doesn't see a partially-initialized structure. Add a new accessor function for it to make this clear. Signed-off-by: Jeff Layton Reviewed-by: Christoph Hellwig --- fs/locks.c | 20 ++++++++++---------- include/linux/fs.h | 14 ++++++++++++++ 2 files changed, 24 insertions(+), 10 deletions(-) diff --git a/fs/locks.c b/fs/locks.c index 9ccf89b6c95d..07436328dd0a 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -175,7 +175,7 @@ locks_get_lock_context(struct inode *inode, int type) struct file_lock_context *ctx; /* paired with cmpxchg() below */ - ctx = smp_load_acquire(&inode->i_flctx); + ctx = locks_inode_context(inode); if (likely(ctx) || type == F_UNLCK) goto out; @@ -194,7 +194,7 @@ locks_get_lock_context(struct inode *inode, int type) */ if (cmpxchg(&inode->i_flctx, NULL, ctx)) { kmem_cache_free(flctx_cache, ctx); - ctx = smp_load_acquire(&inode->i_flctx); + ctx = locks_inode_context(inode); } out: trace_locks_get_lock_context(inode, type, ctx); @@ -891,7 +891,7 @@ posix_test_lock(struct file *filp, struct file_lock *fl) void *owner; void (*func)(void); - ctx = smp_load_acquire(&inode->i_flctx); + ctx = locks_inode_context(inode); if (!ctx || list_empty_careful(&ctx->flc_posix)) { fl->fl_type = F_UNLCK; return; @@ -1483,7 +1483,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) new_fl->fl_flags = type; /* typically we will check that ctx is non-NULL before calling */ - ctx = smp_load_acquire(&inode->i_flctx); + ctx = locks_inode_context(inode); if (!ctx) { WARN_ON_ONCE(1); goto free_lock; @@ -1588,7 +1588,7 @@ void lease_get_mtime(struct inode *inode, struct timespec64 *time) struct file_lock_context *ctx; struct file_lock *fl; - ctx = smp_load_acquire(&inode->i_flctx); + ctx = locks_inode_context(inode); if (ctx && !list_empty_careful(&ctx->flc_lease)) { spin_lock(&ctx->flc_lock); fl = list_first_entry_or_null(&ctx->flc_lease, @@ -1634,7 +1634,7 @@ int fcntl_getlease(struct file *filp) int type = F_UNLCK; LIST_HEAD(dispose); - ctx = smp_load_acquire(&inode->i_flctx); + ctx = locks_inode_context(inode); if (ctx && !list_empty_careful(&ctx->flc_lease)) { percpu_down_read(&file_rwsem); spin_lock(&ctx->flc_lock); @@ -1823,7 +1823,7 @@ static int generic_delete_lease(struct file *filp, void *owner) struct file_lock_context *ctx; LIST_HEAD(dispose); - ctx = smp_load_acquire(&inode->i_flctx); + ctx = locks_inode_context(inode); if (!ctx) { trace_generic_delete_lease(inode, NULL); return error; @@ -2563,7 +2563,7 @@ void locks_remove_posix(struct file *filp, fl_owner_t owner) * posix_lock_file(). Another process could be setting a lock on this * file at the same time, but we wouldn't remove that lock anyway. */ - ctx = smp_load_acquire(&inode->i_flctx); + ctx = locks_inode_context(inode); if (!ctx || list_empty(&ctx->flc_posix)) return; @@ -2684,7 +2684,7 @@ bool vfs_inode_has_locks(struct inode *inode) struct file_lock_context *ctx; bool ret; - ctx = smp_load_acquire(&inode->i_flctx); + ctx = locks_inode_context(inode); if (!ctx) return false; @@ -2865,7 +2865,7 @@ void show_fd_locks(struct seq_file *f, struct file_lock_context *ctx; int id = 0; - ctx = smp_load_acquire(&inode->i_flctx); + ctx = locks_inode_context(inode); if (!ctx) return; diff --git a/include/linux/fs.h b/include/linux/fs.h index d6cb42b7e91c..092673178e13 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1187,6 +1187,13 @@ extern void show_fd_locks(struct seq_file *f, struct file *filp, struct files_struct *files); extern bool locks_owner_has_blockers(struct file_lock_context *flctx, fl_owner_t owner); + +static inline struct file_lock_context * +locks_inode_context(const struct inode *inode) +{ + return smp_load_acquire(&inode->i_flctx); +} + #else /* !CONFIG_FILE_LOCKING */ static inline int fcntl_getlk(struct file *file, unsigned int cmd, struct flock __user *user) @@ -1327,6 +1334,13 @@ static inline bool locks_owner_has_blockers(struct file_lock_context *flctx, { return false; } + +static inline struct file_lock_context * +locks_inode_context(const struct inode *inode) +{ + return NULL; +} + #endif /* !CONFIG_FILE_LOCKING */ static inline struct inode *file_inode(const struct file *f)