From patchwork Fri Mar 27 23:27:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frank van der Linden X-Patchwork-Id: 11463291 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4335281 for ; Fri, 27 Mar 2020 23:27:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 227272073B for ; Fri, 27 Mar 2020 23:27:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="AO5p3cvF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727048AbgC0X1d (ORCPT ); Fri, 27 Mar 2020 19:27:33 -0400 Received: from smtp-fw-4101.amazon.com ([72.21.198.25]:2074 "EHLO smtp-fw-4101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726937AbgC0X1c (ORCPT ); Fri, 27 Mar 2020 19:27:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1585351652; x=1616887652; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=WAV7q+SsqyVjidgxV50ppb2t+UvXzpobe+1ztvalcnY=; b=AO5p3cvFE+7TJd5+HhhcimdGSpNHdCkNtV38CEdFIpMRXh7xCJB+DUeg nAHLXjDAlzud1s/6SoptfCaPoUSICC734hwdAID63ojw8NKK2zt8CbAfj T+mNt+jdAwB1cA6qyUrSn5FWRF2511gHFYtalYYsgclgySkC1U4knZIrH Y=; IronPort-SDR: HDRBX7jIUbximG1vNCLAFlceLmCyCWidEVBA+gYy5s2fKz5/e6uWruoDgbVGjxzqo6Y6RhCBfj Z875MZ+D+nkw== X-IronPort-AV: E=Sophos;i="5.72,314,1580774400"; d="scan'208";a="23245172" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2a-1c1b5cdd.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-4101.iad4.amazon.com with ESMTP; 27 Mar 2020 23:27:18 +0000 Received: from EX13MTAUWA001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2a-1c1b5cdd.us-west-2.amazon.com (Postfix) with ESMTPS id D0847A2346; Fri, 27 Mar 2020 23:27:17 +0000 (UTC) Received: from EX13D13UWA004.ant.amazon.com (10.43.160.251) by EX13MTAUWA001.ant.amazon.com (10.43.160.58) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Fri, 27 Mar 2020 23:27:17 +0000 Received: from EX13MTAUWC001.ant.amazon.com (10.43.162.135) by EX13D13UWA004.ant.amazon.com (10.43.160.251) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 27 Mar 2020 23:27:17 +0000 Received: from dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com (172.23.141.97) by mail-relay.amazon.com (10.43.162.232) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Fri, 27 Mar 2020 23:27:17 +0000 Received: by dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com (Postfix, from userid 6262777) id 31167DEFAE; Fri, 27 Mar 2020 23:27:17 +0000 (UTC) From: Frank van der Linden To: , , CC: Frank van der Linden , , Al Viro Subject: [PATCH v2 01/11] xattr: break delegations in {set,remove}xattr and add _locked versions Date: Fri, 27 Mar 2020 23:27:07 +0000 Message-ID: <20200327232717.15331-2-fllinden@amazon.com> X-Mailer: git-send-email 2.16.6 In-Reply-To: <20200327232717.15331-1-fllinden@amazon.com> References: <20200327232717.15331-1-fllinden@amazon.com> MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org set/removexattr on an exported filesystem should break NFS delegations. This is true in general, but also for the upcoming support for RFC 8726 (NFSv4 extended attribute support). Make sure that they do. Additonally, they need to grow a _locked variant, since the NFS server code will call this with i_rwsem held. It needs to do that in fh_lock to be able to atomically provide the before and after change attributes. Cc: stable@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: Al Viro Signed-off-by: Frank van der Linden --- fs/xattr.c | 84 +++++++++++++++++++++++++++++++++++++++---- include/linux/xattr.h | 2 ++ 2 files changed, 79 insertions(+), 7 deletions(-) diff --git a/fs/xattr.c b/fs/xattr.c index 90dd78f0eb27..f2854570d411 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -204,10 +204,22 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, return error; } - +/** + * __vfs_setxattr_locked: set an extended attribute while holding the inode + * lock + * + * @dentry - object to perform setxattr on + * @name - xattr name to set + * @value - value to set @name to + * @size - size of @value + * @flags - flags to pass into filesystem operations + * @delegated_inode - on return, will contain an inode pointer that + * a delegation was broken on, NULL if none. + */ int -vfs_setxattr(struct dentry *dentry, const char *name, const void *value, - size_t size, int flags) +__vfs_setxattr_locked(struct dentry *dentry, const char *name, + const void *value, size_t size, int flags, + struct inode **delegated_inode) { struct inode *inode = dentry->d_inode; int error; @@ -216,15 +228,40 @@ vfs_setxattr(struct dentry *dentry, const char *name, const void *value, if (error) return error; - inode_lock(inode); error = security_inode_setxattr(dentry, name, value, size, flags); if (error) goto out; + error = try_break_deleg(inode, delegated_inode); + if (error) + goto out; + error = __vfs_setxattr_noperm(dentry, name, value, size, flags); out: + return error; +} +EXPORT_SYMBOL_GPL(__vfs_setxattr_locked); + +int +vfs_setxattr(struct dentry *dentry, const char *name, const void *value, + size_t size, int flags) +{ + struct inode *inode = dentry->d_inode; + struct inode *delegated_inode = NULL; + int error; + +retry_deleg: + inode_lock(inode); + error = __vfs_setxattr_locked(dentry, name, value, size, flags, + &delegated_inode); inode_unlock(inode); + + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } return error; } EXPORT_SYMBOL_GPL(vfs_setxattr); @@ -378,8 +415,18 @@ __vfs_removexattr(struct dentry *dentry, const char *name) } EXPORT_SYMBOL(__vfs_removexattr); +/** + * __vfs_removexattr_locked: set an extended attribute while holding the inode + * lock + * + * @dentry - object to perform setxattr on + * @name - name of xattr to remove + * @delegated_inode - on return, will contain an inode pointer that + * a delegation was broken on, NULL if none. + */ int -vfs_removexattr(struct dentry *dentry, const char *name) +__vfs_removexattr_locked(struct dentry *dentry, const char *name, + struct inode **delegated_inode) { struct inode *inode = dentry->d_inode; int error; @@ -388,11 +435,14 @@ vfs_removexattr(struct dentry *dentry, const char *name) if (error) return error; - inode_lock(inode); error = security_inode_removexattr(dentry, name); if (error) goto out; + error = try_break_deleg(inode, delegated_inode); + if (error) + goto out; + error = __vfs_removexattr(dentry, name); if (!error) { @@ -401,12 +451,32 @@ vfs_removexattr(struct dentry *dentry, const char *name) } out: + return error; +} +EXPORT_SYMBOL_GPL(__vfs_removexattr_locked); + +int +vfs_removexattr(struct dentry *dentry, const char *name) +{ + struct inode *inode = dentry->d_inode; + struct inode *delegated_inode = NULL; + int error; + +retry_deleg: + inode_lock(inode); + error = __vfs_removexattr_locked(dentry, name, &delegated_inode); inode_unlock(inode); + + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } + return error; } EXPORT_SYMBOL_GPL(vfs_removexattr); - /* * Extended attribute SET operations */ diff --git a/include/linux/xattr.h b/include/linux/xattr.h index 6dad031be3c2..3a71ad716da5 100644 --- a/include/linux/xattr.h +++ b/include/linux/xattr.h @@ -51,8 +51,10 @@ ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t); ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size); int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int); int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int); +int __vfs_setxattr_locked(struct dentry *, const char *, const void *, size_t, int, struct inode **); int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int); int __vfs_removexattr(struct dentry *, const char *); +int __vfs_removexattr_locked(struct dentry *, const char *, struct inode **); int vfs_removexattr(struct dentry *, const char *); ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);