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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 AD329C433E0 for ; Fri, 5 Jun 2020 16:25:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D7782074B for ; Fri, 5 Jun 2020 16:25:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Z0yIXMLs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726068AbgFEQZD (ORCPT ); Fri, 5 Jun 2020 12:25:03 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:38265 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726039AbgFEQZC (ORCPT ); Fri, 5 Jun 2020 12:25:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591374300; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=lCmkxymm6xnKjnDSaGxLPoG8GrGLgWHvHPmz6UGUhIw=; b=Z0yIXMLs27JPxE4pQC8yL27rAcg/lBPhhGNz+83ofE2C5N/jGXKg5Grp0dqEO/e49+9Llp 2a6LmBxbJ0D3p0uCf4PNB5+upLvJeVTqRxgjzWdVRMpaFbY17SDlosWd3drWRhu636TXpY 2WPtIbBe45i0n8lL4ZgO0gRLE070Nak= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-201-n-1Zt2PXMmSdUeBxjcQ5nQ-1; Fri, 05 Jun 2020 12:24:55 -0400 X-MC-Unique: n-1Zt2PXMmSdUeBxjcQ5nQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DEBCD835B4A; Fri, 5 Jun 2020 16:24:54 +0000 (UTC) Received: from bfoster (dhcp-41-2.bos.redhat.com [10.18.41.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7022D891C2; Fri, 5 Jun 2020 16:24:54 +0000 (UTC) Date: Fri, 5 Jun 2020 12:24:52 -0400 From: Brian Foster To: Dave Chinner Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH 13/30 V2] xfs: handle buffer log item IO errors directly Message-ID: <20200605162452.GA23747@bfoster> References: <20200604074606.266213-1-david@fromorbit.com> <20200604074606.266213-14-david@fromorbit.com> <20200605013238.GA2040@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200605013238.GA2040@dread.disaster.area> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Fri, Jun 05, 2020 at 11:32:38AM +1000, Dave Chinner wrote: > > From: Dave Chinner > > Currently when a buffer with attached log items has an IO error > it called ->iop_error for each attched log item. These all call > xfs_set_li_failed() to handle the error, but we are about to change > the way log items manage buffers. hence we first need to remove the > per-item dependency on buffer handling done by xfs_set_li_failed(). > > We already have specific buffer type IO completion routines, so move > the log item error handling out of the generic error handling and > into the log item specific functions so we can implement per-type > error handling easily. > > This requires a more complex return value from the error handling > code so that we can take the correct action the failure handling > requires. This results in some repeated boilerplate in the > functions, but that can be cleaned up later once all the changes > cascade through this code. > > Signed-off-by: Dave Chinner > --- > V2: fix buffer retry selection logic braino. > Looks good: Reviewed-by: Brian Foster > fs/xfs/xfs_buf_item.c | 214 +++++++++++++++++++++++++++++++++----------------- > 1 file changed, 144 insertions(+), 70 deletions(-) > > diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c > index 09bfe9c52dbdb..f80fc5bd3bffa 100644 > --- a/fs/xfs/xfs_buf_item.c > +++ b/fs/xfs/xfs_buf_item.c > @@ -986,21 +986,24 @@ xfs_buf_do_callbacks_fail( > spin_unlock(&ailp->ail_lock); > } > > +/* > + * Decide if we're going to retry the write after a failure, and prepare > + * the buffer for retrying the write. > + */ > static bool > -xfs_buf_iodone_callback_error( > +xfs_buf_ioerror_fail_without_retry( > struct xfs_buf *bp) > { > struct xfs_mount *mp = bp->b_mount; > static ulong lasttime; > static xfs_buftarg_t *lasttarg; > - struct xfs_error_cfg *cfg; > > /* > * If we've already decided to shutdown the filesystem because of > * I/O errors, there's no point in giving this a retry. > */ > if (XFS_FORCED_SHUTDOWN(mp)) > - goto out_stale; > + return true; > > if (bp->b_target != lasttarg || > time_after(jiffies, (lasttime + 5*HZ))) { > @@ -1011,91 +1014,114 @@ xfs_buf_iodone_callback_error( > > /* synchronous writes will have callers process the error */ > if (!(bp->b_flags & XBF_ASYNC)) > - goto out_stale; > - > - trace_xfs_buf_item_iodone_async(bp, _RET_IP_); > - > - cfg = xfs_error_get_cfg(mp, XFS_ERR_METADATA, bp->b_error); > + return true; > + return false; > +} > > - /* > - * If the write was asynchronous then no one will be looking for the > - * error. If this is the first failure of this type, clear the error > - * state and write the buffer out again. This means we always retry an > - * async write failure at least once, but we also need to set the buffer > - * up to behave correctly now for repeated failures. > - */ > - if (!(bp->b_flags & (XBF_STALE | XBF_WRITE_FAIL)) || > - bp->b_last_error != bp->b_error) { > - bp->b_flags |= (XBF_WRITE | XBF_DONE | XBF_WRITE_FAIL); > - bp->b_last_error = bp->b_error; > - if (cfg->retry_timeout != XFS_ERR_RETRY_FOREVER && > - !bp->b_first_retry_time) > - bp->b_first_retry_time = jiffies; > +static bool > +xfs_buf_ioerror_retry( > + struct xfs_buf *bp, > + struct xfs_error_cfg *cfg) > +{ > + if ((bp->b_flags & (XBF_STALE | XBF_WRITE_FAIL)) && > + bp->b_last_error == bp->b_error) > + return false; > > - xfs_buf_ioerror(bp, 0); > - xfs_buf_submit(bp); > - return true; > - } > + bp->b_flags |= (XBF_WRITE | XBF_DONE | XBF_WRITE_FAIL); > + bp->b_last_error = bp->b_error; > + if (cfg->retry_timeout != XFS_ERR_RETRY_FOREVER && > + !bp->b_first_retry_time) > + bp->b_first_retry_time = jiffies; > + return true; > +} > > - /* > - * Repeated failure on an async write. Take action according to the > - * error configuration we have been set up to use. > - */ > +/* > + * Account for this latest trip around the retry handler, and decide if > + * we've failed enough times to constitute a permanent failure. > + */ > +static bool > +xfs_buf_ioerror_permanent( > + struct xfs_buf *bp, > + struct xfs_error_cfg *cfg) > +{ > + struct xfs_mount *mp = bp->b_mount; > > if (cfg->max_retries != XFS_ERR_RETRY_FOREVER && > ++bp->b_retries > cfg->max_retries) > - goto permanent_error; > + return true; > if (cfg->retry_timeout != XFS_ERR_RETRY_FOREVER && > time_after(jiffies, cfg->retry_timeout + bp->b_first_retry_time)) > - goto permanent_error; > + return true; > > /* At unmount we may treat errors differently */ > if ((mp->m_flags & XFS_MOUNT_UNMOUNTING) && mp->m_fail_unmount) > - goto permanent_error; > - > - /* > - * Still a transient error, run IO completion failure callbacks and let > - * the higher layers retry the buffer. > - */ > - xfs_buf_do_callbacks_fail(bp); > - xfs_buf_ioerror(bp, 0); > - xfs_buf_relse(bp); > - return true; > + return true; > > - /* > - * Permanent error - we need to trigger a shutdown if we haven't already > - * to indicate that inconsistency will result from this action. > - */ > -permanent_error: > - xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR); > -out_stale: > - xfs_buf_stale(bp); > - bp->b_flags |= XBF_DONE; > - trace_xfs_buf_error_relse(bp, _RET_IP_); > return false; > } > > -static inline bool > -xfs_buf_had_callback_errors( > +/* > + * On a sync write or shutdown we just want to stale the buffer and let the > + * caller handle the error in bp->b_error appropriately. > + * > + * If the write was asynchronous then no one will be looking for the error. If > + * this is the first failure of this type, clear the error state and write the > + * buffer out again. This means we always retry an async write failure at least > + * once, but we also need to set the buffer up to behave correctly now for > + * repeated failures. > + * > + * If we get repeated async write failures, then we take action according to the > + * error configuration we have been set up to use. > + * > + * Multi-state return value: > + * > + * XBF_IOERROR_FINISH: clear IO error retry state and run callback completions > + * XBF_IOERROR_DONE: resubmitted immediately, do not run any completions > + * XBF_IOERROR_FAIL: transient error, run failure callback completions and then > + * release the buffer > + */ > +enum { > + XBF_IOERROR_FINISH, > + XBF_IOERROR_DONE, > + XBF_IOERROR_FAIL, > +}; > + > +static int > +xfs_buf_iodone_error( > struct xfs_buf *bp) > { > + struct xfs_mount *mp = bp->b_mount; > + struct xfs_error_cfg *cfg; > > - /* > - * If there is an error, process it. Some errors require us to run > - * callbacks after failure processing is done so we detect that and take > - * appropriate action. > - */ > - if (bp->b_error && xfs_buf_iodone_callback_error(bp)) > - return true; > + if (xfs_buf_ioerror_fail_without_retry(bp)) > + goto out_stale; > + > + trace_xfs_buf_item_iodone_async(bp, _RET_IP_); > + > + cfg = xfs_error_get_cfg(mp, XFS_ERR_METADATA, bp->b_error); > + if (xfs_buf_ioerror_retry(bp, cfg)) { > + xfs_buf_ioerror(bp, 0); > + xfs_buf_submit(bp); > + return XBF_IOERROR_DONE; > + } > > /* > - * Successful IO or permanent error. Either way, we can clear the > - * retry state here in preparation for the next error that may occur. > + * Permanent error - we need to trigger a shutdown if we haven't already > + * to indicate that inconsistency will result from this action. > */ > - bp->b_last_error = 0; > - bp->b_retries = 0; > - bp->b_first_retry_time = 0; > - return false; > + if (xfs_buf_ioerror_permanent(bp, cfg)) { > + xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR); > + goto out_stale; > + } > + > + /* Still considered a transient error. Caller will schedule retries. */ > + return XBF_IOERROR_FAIL; > + > +out_stale: > + xfs_buf_stale(bp); > + bp->b_flags |= XBF_DONE; > + trace_xfs_buf_error_relse(bp, _RET_IP_); > + return XBF_IOERROR_FINISH; > } > > static void > @@ -1122,6 +1148,15 @@ xfs_buf_item_done( > xfs_buf_rele(bp); > } > > +static inline void > +xfs_buf_clear_ioerror_retry_state( > + struct xfs_buf *bp) > +{ > + bp->b_last_error = 0; > + bp->b_retries = 0; > + bp->b_first_retry_time = 0; > +} > + > /* > * Inode buffer iodone callback function. > */ > @@ -1129,9 +1164,22 @@ void > xfs_buf_inode_iodone( > struct xfs_buf *bp) > { > - if (xfs_buf_had_callback_errors(bp)) > + if (bp->b_error) { > + int ret = xfs_buf_iodone_error(bp); > + > + if (ret == XBF_IOERROR_FINISH) > + goto finish_iodone; > + if (ret == XBF_IOERROR_DONE) > + return; > + ASSERT(ret == XBF_IOERROR_FAIL); > + xfs_buf_do_callbacks_fail(bp); > + xfs_buf_ioerror(bp, 0); > + xfs_buf_relse(bp); > return; > + } > > +finish_iodone: > + xfs_buf_clear_ioerror_retry_state(bp); > xfs_buf_item_done(bp); > xfs_iflush_done(bp); > xfs_buf_ioend_finish(bp); > @@ -1144,9 +1192,22 @@ void > xfs_buf_dquot_iodone( > struct xfs_buf *bp) > { > - if (xfs_buf_had_callback_errors(bp)) > + if (bp->b_error) { > + int ret = xfs_buf_iodone_error(bp); > + > + if (ret == XBF_IOERROR_FINISH) > + goto finish_iodone; > + if (ret == XBF_IOERROR_DONE) > + return; > + ASSERT(ret == XBF_IOERROR_FAIL); > + xfs_buf_do_callbacks_fail(bp); > + xfs_buf_ioerror(bp, 0); > + xfs_buf_relse(bp); > return; > + } > > +finish_iodone: > + xfs_buf_clear_ioerror_retry_state(bp); > /* a newly allocated dquot buffer might have a log item attached */ > xfs_buf_item_done(bp); > xfs_dquot_done(bp); > @@ -1163,9 +1224,22 @@ void > xfs_buf_iodone( > struct xfs_buf *bp) > { > - if (xfs_buf_had_callback_errors(bp)) > + if (bp->b_error) { > + int ret = xfs_buf_iodone_error(bp); > + > + if (ret == XBF_IOERROR_FINISH) > + goto finish_iodone; > + if (ret == XBF_IOERROR_DONE) > + return; > + ASSERT(ret == XBF_IOERROR_FAIL); > + xfs_buf_do_callbacks_fail(bp); > + xfs_buf_ioerror(bp, 0); > + xfs_buf_relse(bp); > return; > + } > > +finish_iodone: > + xfs_buf_clear_ioerror_retry_state(bp); > xfs_buf_item_done(bp); > xfs_buf_ioend_finish(bp); > } >