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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F244C433FE for ; Tue, 12 Apr 2022 04:26:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345806AbiDLE2R (ORCPT ); Tue, 12 Apr 2022 00:28:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51522 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345813AbiDLE2K (ORCPT ); Tue, 12 Apr 2022 00:28:10 -0400 Received: from mail105.syd.optusnet.com.au (mail105.syd.optusnet.com.au [211.29.132.249]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2C95A329A0 for ; Mon, 11 Apr 2022 21:25:53 -0700 (PDT) Received: from dread.disaster.area (pa49-186-233-190.pa.vic.optusnet.com.au [49.186.233.190]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id 70D8E10C7C14; Tue, 12 Apr 2022 14:25:47 +1000 (AEST) Received: from discord.disaster.area ([192.168.253.110]) by dread.disaster.area with esmtp (Exim 4.92.3) (envelope-from ) id 1ne865-00Gh2K-So; Tue, 12 Apr 2022 14:25:45 +1000 Received: from dave by discord.disaster.area with local (Exim 4.95) (envelope-from ) id 1ne865-009NrI-Rg; Tue, 12 Apr 2022 14:25:45 +1000 From: Dave Chinner To: linux-xfs@vger.kernel.org Cc: allison.henderson@oracle.com Subject: [PATCH 01/10] xfs: avoid empty xattr transaction when attrs are inline Date: Tue, 12 Apr 2022 14:25:34 +1000 Message-Id: <20220412042543.2234866-2-david@fromorbit.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412042543.2234866-1-david@fromorbit.com> References: <20220412042543.2234866-1-david@fromorbit.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.4 cv=VuxAv86n c=1 sm=1 tr=0 ts=6254ff4b a=bHAvQTfMiaNt/bo4vVGwyA==:117 a=bHAvQTfMiaNt/bo4vVGwyA==:17 a=z0gMJWrwH1QA:10 a=20KFwNOVAAAA:8 a=z6sQ9X07RN1rA8HuyEwA:9 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Dave Chinner generic/642 triggered a reproducable assert failure in xlog_cil_commit() that resulted from a xfs_attr_set() committing an empty but dirty transaction. When the CIL is empty and this occurs, xlog_cil_commit() tries a background push and this triggers a "pushing an empty CIL" assert. XFS: Assertion failed: !list_empty(&cil->xc_cil), file: fs/xfs/xfs_log_cil.c, line: 1274 Call Trace: xlog_cil_commit+0xa5a/0xad0 __xfs_trans_commit+0xb8/0x330 xfs_trans_commit+0x10/0x20 xfs_attr_set+0x3e2/0x4c0 xfs_xattr_set+0x8d/0xe0 __vfs_setxattr+0x6b/0x90 __vfs_setxattr_noperm+0x76/0x220 __vfs_setxattr_locked+0xdf/0x100 vfs_setxattr+0x94/0x170 setxattr+0x110/0x200 path_setxattr+0xbf/0xe0 __x64_sys_setxattr+0x2b/0x30 do_syscall_64+0x35/0x80 The problem is related to the breakdown of attribute addition in xfs_attr_set_iter() and how it is called from deferred operations. When we have a pure leaf xattr insert, we add the xattr to the leaf and set the next state to XFS_DAS_FOUND_LBLK and return -EAGAIN. This requeues the xattr defered work, rolls the transaction and runs xfs_attr_set_iter() again. This then checks the xattr for being remote (it's not) and whether a replace op is being done (this is a create op) and if neither are true it returns without having done anything. xfs_xattri_finish_update() then unconditionally sets the transaction dirty, and the deferops finishes and returns to __xfs_trans_commit() which sees the transaction dirty and tries to commit it by calling xlog_cil_commit(). The transaction is empty, and then the assert fires if this happens when the CIL is empty. This patch addresses the structure of xfs_attr_set_iter() that requires re-entry on leaf add even when nothing will be done. This gets rid of the trailing empty transaction and so doesn't trigger the XFS_TRANS_DIRTY assignment in xfs_xattri_finish_update() incorrectly. Addressing that is for a different patch. Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_attr.c | 39 +++++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 20 deletions(-) diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c index 48b7e7efbb30..b3d918195160 100644 --- a/fs/xfs/libxfs/xfs_attr.c +++ b/fs/xfs/libxfs/xfs_attr.c @@ -315,6 +315,7 @@ xfs_attr_leaf_addname( { struct xfs_da_args *args = attr->xattri_da_args; struct xfs_inode *dp = args->dp; + enum xfs_delattr_state next_state = XFS_DAS_UNINIT; int error; if (xfs_attr_is_leaf(dp)) { @@ -335,37 +336,35 @@ xfs_attr_leaf_addname( * when we come back, we'll be a node, so we'll fall * down into the node handling code below */ - trace_xfs_attr_set_iter_return( - attr->xattri_dela_state, args->dp); - return -EAGAIN; + error = -EAGAIN; + goto out; } - - if (error) - return error; - - attr->xattri_dela_state = XFS_DAS_FOUND_LBLK; + next_state = XFS_DAS_FOUND_LBLK; } else { error = xfs_attr_node_addname_find_attr(attr); if (error) return error; + next_state = XFS_DAS_FOUND_NBLK; error = xfs_attr_node_addname(attr); - if (error) - return error; - - /* - * If addname was successful, and we dont need to alloc or - * remove anymore blks, we're done. - */ - if (!args->rmtblkno && - !(args->op_flags & XFS_DA_OP_RENAME)) - return 0; + } + if (error) + return error; - attr->xattri_dela_state = XFS_DAS_FOUND_NBLK; + /* + * We need to commit and roll if we need to allocate remote xattr blocks + * or perform more xattr manipulations. Otherwise there is nothing more + * to do and we can return success. + */ + if (args->rmtblkno || + (args->op_flags & XFS_DA_OP_RENAME)) { + attr->xattri_dela_state = next_state; + error = -EAGAIN; } +out: trace_xfs_attr_leaf_addname_return(attr->xattri_dela_state, args->dp); - return -EAGAIN; + return error; } /* -- 2.35.1