From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C81F7C43381 for ; Wed, 20 Feb 2019 10:26:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 96FEA2147C for ; Wed, 20 Feb 2019 10:26:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550658366; bh=lu2eN7JfhMjLIWNkWCthhunCnSaF+YsFvZBjv4FkZ/k=; h=Subject:To:From:Date:List-ID:From; b=Udixxp4oSa3EIbKMkCB2hNVH4pL0gaznhVyeJgHHtjdS3Q2zirrqb7e+a2E1GF2KD 2wHLNKfb+jVm4di+Ef90LGUECoJKGcE9rjmTprTmiJxXrAGFVoCv9QgBPSHl8vC4WZ wGL8lQxyWGQ5IQm/pBqOrMnpxVP+O7x1cU+KhSoE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726760AbfBTK0F (ORCPT ); Wed, 20 Feb 2019 05:26:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:47562 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726283AbfBTK0F (ORCPT ); Wed, 20 Feb 2019 05:26:05 -0500 Received: from localhost (unknown [195.134.171.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6C18F2146E; Wed, 20 Feb 2019 10:26:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550658364; bh=lu2eN7JfhMjLIWNkWCthhunCnSaF+YsFvZBjv4FkZ/k=; h=Subject:To:From:Date:From; b=UZFFzbG7n1d+DWioWJxKOXqfX3TBxekAlJhK487FNviO+PUYcLqDBEV/rcoYoSPyw vBTyz498Qq4F/b+Kv1Y1x2sqpzY4j8s1rxk9yq7vD8mC+RakcBwa/lEzhxMa2A5qc1 wbZAFWlLzqRJkJ8uWTciY7EFR9FOOWmz4XUTO/Fw= Subject: patch "staging: erofs: fix race of initializing xattrs of a inode at the" added to staging-testing To: gaoxiang25@huawei.com, gregkh@linuxfoundation.org, stable@vger.kernel.org, yuchao0@huawei.com From: Date: Wed, 20 Feb 2019 11:25:58 +0100 Message-ID: <155065835813052@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled staging: erofs: fix race of initializing xattrs of a inode at the to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-testing branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will be merged to the staging-next branch sometime soon, after it passes testing, and the merge window is open. If you have any questions about this process, please let me know. >From 62dc45979f3f8cb0ea67302a93bff686f0c46c5a Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Mon, 18 Feb 2019 15:19:04 +0800 Subject: staging: erofs: fix race of initializing xattrs of a inode at the same time In real scenario, there could be several threads accessing xattrs of the same xattr-uninitialized inode, and init_inode_xattrs() almost at the same time. That's actually an unexpected behavior, this patch closes the race. Fixes: b17500a0fdba ("staging: erofs: introduce xattr & acl support") Cc: # 4.19+ Reviewed-by: Chao Yu Signed-off-by: Gao Xiang Signed-off-by: Greg Kroah-Hartman --- drivers/staging/erofs/internal.h | 11 ++++++--- drivers/staging/erofs/xattr.c | 41 ++++++++++++++++++++++---------- 2 files changed, 37 insertions(+), 15 deletions(-) diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h index 3a27c255950b..e3bfde00c7d2 100644 --- a/drivers/staging/erofs/internal.h +++ b/drivers/staging/erofs/internal.h @@ -327,12 +327,17 @@ static inline erofs_off_t iloc(struct erofs_sb_info *sbi, erofs_nid_t nid) return blknr_to_addr(sbi->meta_blkaddr) + (nid << sbi->islotbits); } -#define inode_set_inited_xattr(inode) (EROFS_V(inode)->flags |= 1) -#define inode_has_inited_xattr(inode) (EROFS_V(inode)->flags & 1) +/* atomic flag definitions */ +#define EROFS_V_EA_INITED_BIT 0 + +/* bitlock definitions (arranged in reverse order) */ +#define EROFS_V_BL_XATTR_BIT (BITS_PER_LONG - 1) struct erofs_vnode { erofs_nid_t nid; - unsigned int flags; + + /* atomic flags (including bitlocks) */ + unsigned long flags; unsigned char data_mapping_mode; /* inline size in bytes */ diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c index 8c48b0ab31fd..f716ab0446e5 100644 --- a/drivers/staging/erofs/xattr.c +++ b/drivers/staging/erofs/xattr.c @@ -44,18 +44,25 @@ static inline void xattr_iter_end_final(struct xattr_iter *it) static int init_inode_xattrs(struct inode *inode) { + struct erofs_vnode *const vi = EROFS_V(inode); struct xattr_iter it; unsigned int i; struct erofs_xattr_ibody_header *ih; struct super_block *sb; struct erofs_sb_info *sbi; - struct erofs_vnode *vi; bool atomic_map; + int ret = 0; - if (likely(inode_has_inited_xattr(inode))) + /* the most case is that xattrs of this inode are initialized. */ + if (test_bit(EROFS_V_EA_INITED_BIT, &vi->flags)) return 0; - vi = EROFS_V(inode); + if (wait_on_bit_lock(&vi->flags, EROFS_V_BL_XATTR_BIT, TASK_KILLABLE)) + return -ERESTARTSYS; + + /* someone has initialized xattrs for us? */ + if (test_bit(EROFS_V_EA_INITED_BIT, &vi->flags)) + goto out_unlock; /* * bypass all xattr operations if ->xattr_isize is not greater than @@ -68,13 +75,16 @@ static int init_inode_xattrs(struct inode *inode) if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) { errln("xattr_isize %d of nid %llu is not supported yet", vi->xattr_isize, vi->nid); - return -ENOTSUPP; + ret = -ENOTSUPP; + goto out_unlock; } else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) { if (unlikely(vi->xattr_isize)) { DBG_BUGON(1); - return -EIO; /* xattr ondisk layout error */ + ret = -EIO; + goto out_unlock; /* xattr ondisk layout error */ } - return -ENOATTR; + ret = -ENOATTR; + goto out_unlock; } sb = inode->i_sb; @@ -83,8 +93,10 @@ static int init_inode_xattrs(struct inode *inode) it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize); it.page = erofs_get_inline_page(inode, it.blkaddr); - if (IS_ERR(it.page)) - return PTR_ERR(it.page); + if (IS_ERR(it.page)) { + ret = PTR_ERR(it.page); + goto out_unlock; + } /* read in shared xattr array (non-atomic, see kmalloc below) */ it.kaddr = kmap(it.page); @@ -97,7 +109,8 @@ static int init_inode_xattrs(struct inode *inode) sizeof(uint), GFP_KERNEL); if (vi->xattr_shared_xattrs == NULL) { xattr_iter_end(&it, atomic_map); - return -ENOMEM; + ret = -ENOMEM; + goto out_unlock; } /* let's skip ibody header */ @@ -114,7 +127,8 @@ static int init_inode_xattrs(struct inode *inode) if (IS_ERR(it.page)) { kfree(vi->xattr_shared_xattrs); vi->xattr_shared_xattrs = NULL; - return PTR_ERR(it.page); + ret = PTR_ERR(it.page); + goto out_unlock; } it.kaddr = kmap_atomic(it.page); @@ -127,8 +141,11 @@ static int init_inode_xattrs(struct inode *inode) } xattr_iter_end(&it, atomic_map); - inode_set_inited_xattr(inode); - return 0; + set_bit(EROFS_V_EA_INITED_BIT, &vi->flags); + +out_unlock: + clear_and_wake_up_bit(EROFS_V_BL_XATTR_BIT, &vi->flags); + return ret; } /* -- 2.20.1