From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net ([212.227.15.18]:62971 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750762AbdIWHWz (ORCPT ); Sat, 23 Sep 2017 03:22:55 -0400 Subject: Re: [PATCH] btrfs: Remove WARN_ON for unaligned device created before v4.13 and adds more user friendly output To: Satoru Takeuchi Cc: linux-btrfs@vger.kernel.org, dsterba@suse.cz, rich@shroop.net, rrauenza@gmail.com References: <20170920061843.9016-1-quwenruo.btrfs@gmx.com> <87bmm25i01.wl-satoru.takeuchi@gmail.com> <87a81m5hm1.wl-satoru.takeuchi@gmail.com> From: Qu Wenruo Message-ID: Date: Sat, 23 Sep 2017 15:22:36 +0800 MIME-Version: 1.0 In-Reply-To: <87a81m5hm1.wl-satoru.takeuchi@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 2017年09月23日 09:27, Satoru Takeuchi wrote: > At Sat, 23 Sep 2017 10:19:26 +0900, > Satoru Takeuchi wrote: >> >> At Wed, 20 Sep 2017 15:18:43 +0900, >> Qu Wenruo wrote: >>> >>> Commit 7dfb8be11b5d ("btrfs: Round down values which are written for >>> total_bytes_size") is fixing the unaligned device size caused by >>> adding/shrinking device. >>> >>> It added a new WARN_ON() when device size is unaligned. >>> This is fine for new device added to btrfs using v4.13 kernel, but not >>> existing device whose total_bytes is already unaligned. >>> >>> And the WARN_ON() will get triggered every time a block group get >>> created/removed on the unaligned device. >>> >>> This patch will remove the WARN_ON(), and warn user more gently what's >>> happening and how to fix it. >>> >>> Reported-by: Rich Rauenzahn >>> Fixes: 7dfb8be11b5d ("btrfs: Round down values which are written for >>> total_bytes_size") >>> Signed-off-by: Qu Wenruo >>> --- >>> fs/btrfs/ctree.h | 1 - >>> fs/btrfs/volumes.c | 16 ++++++++++++---- >>> 2 files changed, 12 insertions(+), 5 deletions(-) >>> >>> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h >>> index 5a8933da39a7..4de9269e435a 100644 >>> --- a/fs/btrfs/ctree.h >>> +++ b/fs/btrfs/ctree.h >>> @@ -1562,7 +1562,6 @@ static inline void btrfs_set_device_total_bytes(struct extent_buffer *eb, >>> { >>> BUILD_BUG_ON(sizeof(u64) != >>> sizeof(((struct btrfs_dev_item *)0))->total_bytes); >>> - WARN_ON(!IS_ALIGNED(val, eb->fs_info->sectorsize)); >>> btrfs_set_64(eb, s, offsetof(struct btrfs_dev_item, total_bytes), val); >>> } >>> >>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c >>> index 0e8f16c305df..afae25df6a8c 100644 >>> --- a/fs/btrfs/volumes.c >>> +++ b/fs/btrfs/volumes.c >>> @@ -6472,15 +6472,23 @@ static int read_one_chunk(struct btrfs_fs_info *fs_info, struct btrfs_key *key, >>> return 0; >>> } >>> >>> -static void fill_device_from_item(struct extent_buffer *leaf, >>> - struct btrfs_dev_item *dev_item, >>> - struct btrfs_device *device) >>> +static void fill_device_from_item(struct btrfs_fs_info *fs_info, >>> + struct extent_buffer *leaf, >>> + struct btrfs_dev_item *dev_item, >>> + struct btrfs_device *device) >>> { >>> unsigned long ptr; >>> >>> device->devid = btrfs_device_id(leaf, dev_item); >>> device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item); >>> device->total_bytes = device->disk_total_bytes; >>> + if (!IS_ALIGNED(device->total_bytes, fs_info->sectorsize)) { >>> + btrfs_warn(fs_info, >>> + "devid %llu has unaligned total bytes %llu", >>> + device->devid, device->disk_total_bytes); >>> + btrfs_warn(fs_info, >>> + "please shrink the device a little and resize back to fix it"); >>> + } >> >> How about telling uses to know device->total_bytes should be alligned >> to fs_info->sectorsize here? >> >> Thanks, > > I should make my comment clearer, sorry. > > === > + if (!IS_ALIGNED(device->total_bytes, fs_info->sectorsize)) { > + btrfs_warn(fs_info, > + "devid %llu: total bytes %llu should be aligned to %u bytes", > + device->devid, device->disk_total_bytes, fs_info->sectorsize); > + btrfs_warn(fs_info, > + "please shrink the device a little and resize back to fix it"); > + } > === That's better. But I'm also considering modifying the total_bytes directly here. So that any time DEV_ITEM and super block get updated, new aligned value will be written back to disk, and since the value is aligned in memory, it won't cause WARN_ON() any longer. I'll test and check the code for confirmation before updating the patch. Thanks, Qu > > Thanks, > Satoru > >> Satoru >> >>> device->commit_total_bytes = device->disk_total_bytes; >>> device->bytes_used = btrfs_device_bytes_used(leaf, dev_item); >>> device->commit_bytes_used = device->bytes_used; >>> @@ -6625,7 +6633,7 @@ static int read_one_dev(struct btrfs_fs_info *fs_info, >>> return -EINVAL; >>> } >>> >>> - fill_device_from_item(leaf, dev_item, device); >>> + fill_device_from_item(fs_info, leaf, dev_item, device); >>> device->in_fs_metadata = 1; >>> if (device->writeable && !device->is_tgtdev_for_dev_replace) { >>> device->fs_devices->total_rw_bytes += device->total_bytes; >>> -- >>> 2.14.1 >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html