From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from tyo162.gate.nec.co.jp ([114.179.232.162]:38535 "EHLO tyo162.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752800AbdBCH4s (ORCPT ); Fri, 3 Feb 2017 02:56:48 -0500 From: Junichi Nomura To: "linux-block@vger.kernel.org" , linux-scsi Subject: [REGRESSION v4.10-rc1] blkdev_issue_zeroout() returns -EREMOTEIO on the first call for SCSI device that doesn't support WRITE SAME Date: Fri, 3 Feb 2017 07:55:38 +0000 Message-ID: Content-Type: text/plain; charset="iso-2022-jp" MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org I found following ext4 error occurs on a certain storage since v4.10-rc1: EXT4-fs (sdc1): Delayed block allocation failed for inode 12 at logical offset 100 with max blocks 2 with error 121 EXT4-fs (sdc1): This should not happen!! Data will be lost Error 121 (EREMOTEIO) was returned from blkdev_issue_zeroout(). That came from sd driver because WRITE SAME was sent to the device which didn't support it. The problem was introduced by commit e73c23ff736e ("block: add async variant of blkdev_issue_zeroout"). Before the commit, blkdev_issue_zeroout fell back to normal zero writing when WRITE SAME failed and it seems sd driver's heuristics depends on that behaviour. Below is a band-aid fix to restore the fallback behaviour for sd. Although there should be better fix as retrying blindly is not a good idea... v4.10-rc6: # cat /sys/block/sdc/queue/write_same_max_bytes 33553920 # fallocate -v -z -l 512 /dev/sdc1 fallocate: fallocate failed: Remote I/O error # cat /sys/block/sdc/queue/write_same_max_bytes 0 # fallocate -v -z -l 512 /dev/sdc1 # echo $? 0 v4.9 or v4.10-rc6 + this patch: # grep . /sys/block/sdc/queue/write_same_max_bytes 33553920 # fallocate -v -z -l 512 /dev/sdc1 # echo $? 0 # grep . /sys/block/sdc/queue/write_same_max_bytes 0 diff --git a/block/blk-lib.c b/block/blk-lib.c index f8c82a9..8e53474 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -360,6 +360,7 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask, bool discard) { int ret; + int pass = 0; struct bio *bio = NULL; struct blk_plug plug; @@ -369,6 +370,7 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, return 0; } + retry_other_method: blk_start_plug(&plug); ret = __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask, &bio, discard); @@ -378,6 +380,11 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, } blk_finish_plug(&plug); + if (ret && pass++ == 0) { + bio = NULL; + goto retry_other_method; + } + return ret; } EXPORT_SYMBOL(blkdev_issue_zeroout); -- Jun'ichi Nomura, NEC Corporation / NEC Solution Innovators, Ltd.