From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f170.google.com ([209.85.223.170]:35451 "EHLO mail-io0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753773AbcJKQTL (ORCPT ); Tue, 11 Oct 2016 12:19:11 -0400 Received: by mail-io0-f170.google.com with SMTP id i202so29924561ioi.2 for ; Tue, 11 Oct 2016 09:19:10 -0700 (PDT) From: "Jason D. Michaelson" To: "'Chris Murphy'" Cc: "'Btrfs BTRFS'" References: <5cde01d2230f$fa1e3150$ee5a93f0$@com> <5ce201d22364$96702780$c3507680$@com> <5e8501d223d7$715a9bb0$540fd310$@com> In-Reply-To: Subject: RE: raid6 file system in a bad state Date: Tue, 11 Oct 2016 11:10:55 -0500 Message-ID: <5e8601d223da$0cbf6c00$263e4400$@com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Sender: linux-btrfs-owner@vger.kernel.org List-ID: > > > Bad superblocks can't be a good thing and would only cause confusion. > I'd think that a known bad superblock would be ignored at mount time > and even by btrfs-find-root, or maybe even replaced like any other kind > of known bad metadata where good copies are available. > > btrfs-show-super -f /dev/sda > btrfs-show-super -f /dev/sdh > > > Find out what the difference is between good and bad supers. > root@castor:~# btrfs-show-super -f /dev/sda superblock: bytenr=65536, device=/dev/sda --------------------------------------------------------- csum_type 0 (crc32c) csum_size 4 csum 0x45278835 [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 73ed01df-fb2a-4b27-b6fc-12a57da934bd label generation 161562 root 5752616386560 sys_array_size 354 chunk_root_generation 156893 root_level 1 chunk_root 20971520 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 18003557892096 bytes_used 7107627130880 sectorsize 4096 nodesize 16384 leafsize 16384 stripesize 4096 root_dir 6 num_devices 6 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0xe1 ( MIXED_BACKREF | BIG_METADATA | EXTENDED_IREF | RAID56 ) cache_generation 161562 uuid_tree_generation 161562 dev_item.uuid 08c50aa9-c2dd-43b7-a631-6dfdc7d69ea4 dev_item.fsid 73ed01df-fb2a-4b27-b6fc-12a57da934bd [match] dev_item.type 0 dev_item.total_bytes 3000592982016 dev_item.bytes_used 1800957198336 dev_item.io_align 4096 dev_item.io_width 4096 dev_item.sector_size 4096 dev_item.devid 1 dev_item.dev_group 0 dev_item.seek_speed 0 dev_item.bandwidth 0 dev_item.generation 0 sys_chunk_array[2048]: item 0 key (FIRST_CHUNK_TREE CHUNK_ITEM 0) chunk length 4194304 owner 2 stripe_len 65536 type SYSTEM num_stripes 1 stripe 0 devid 1 offset 0 dev uuid: 08c50aa9-c2dd-43b7-a631-6dfdc7d69ea4 item 1 key (FIRST_CHUNK_TREE CHUNK_ITEM 20971520) chunk length 11010048 owner 2 stripe_len 65536 type SYSTEM|RAID6 num_stripes 6 stripe 0 devid 6 offset 1048576 dev uuid: 390a1fd8-cc6c-40e7-b0b5-88ca7dcbcc32 stripe 1 devid 5 offset 1048576 dev uuid: 2df974c5-9dde-4062-81e9-c6eeee13db62 stripe 2 devid 4 offset 1048576 dev uuid: dce3d159-721d-4859-9955-37a03769bb0d stripe 3 devid 3 offset 1048576 dev uuid: 6f7142db-824c-4791-a5b2-d6ce11c81c8f stripe 4 devid 2 offset 1048576 dev uuid: dc8760f1-2c54-4134-a9a7-a0ac2b7a9f1c stripe 5 devid 1 offset 20971520 dev uuid: 08c50aa9-c2dd-43b7-a631-6dfdc7d69ea4 backup_roots[4]: backup 0: backup_tree_root: 5752437456896 gen: 161561 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 backup_extent_root: 5752385224704 gen: 161561 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 backup_dev_root: 5752437587968 gen: 161561 level: 1 backup_csum_root: 5752389615616 gen: 161561 level: 3 backup_total_bytes: 18003557892096 backup_bytes_used: 7112579833856 backup_num_devices: 6 backup 1: backup_tree_root: 5752616386560 gen: 161562 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 backup_extent_root: 5752649416704 gen: 161563 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 backup_dev_root: 5752616501248 gen: 161562 level: 1 backup_csum_root: 5752650203136 gen: 161563 level: 3 backup_total_bytes: 18003557892096 backup_bytes_used: 7107602407424 backup_num_devices: 6 backup 2: backup_tree_root: 5752112103424 gen: 161559 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 backup_extent_root: 5752207409152 gen: 161560 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 backup_dev_root: 5752113463296 gen: 161559 level: 1 backup_csum_root: 5752205492224 gen: 161560 level: 3 backup_total_bytes: 18003557892096 backup_bytes_used: 7112514002944 backup_num_devices: 6 backup 3: backup_tree_root: 5752298307584 gen: 161560 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 backup_extent_root: 5752385224704 gen: 161561 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 backup_dev_root: 5752299978752 gen: 161560 level: 1 backup_csum_root: 5752389615616 gen: 161561 level: 3 backup_total_bytes: 18003557892096 backup_bytes_used: 7112542425088 backup_num_devices: 6 root@castor:~# btrfs-show-super -f /dev/sdh superblock: bytenr=65536, device=/dev/sdh --------------------------------------------------------- csum_type 0 (crc32c) csum_size 4 csum 0x0f7dfe09 [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 73ed01df-fb2a-4b27-b6fc-12a57da934bd label generation 161474 root 4844272943104 sys_array_size 354 chunk_root_generation 156893 root_level 1 chunk_root 20971520 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 18003557892096 bytes_used 7110395990016 sectorsize 4096 nodesize 16384 leafsize 16384 stripesize 4096 root_dir 6 num_devices 6 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0xe1 ( MIXED_BACKREF | BIG_METADATA | EXTENDED_IREF | RAID56 ) cache_generation 161474 uuid_tree_generation 161474 dev_item.uuid dc8760f1-2c54-4134-a9a7-a0ac2b7a9f1c dev_item.fsid 73ed01df-fb2a-4b27-b6fc-12a57da934bd [match] dev_item.type 0 dev_item.total_bytes 3000592982016 dev_item.bytes_used 1800936226816 dev_item.io_align 4096 dev_item.io_width 4096 dev_item.sector_size 4096 dev_item.devid 2 dev_item.dev_group 0 dev_item.seek_speed 0 dev_item.bandwidth 0 dev_item.generation 0 sys_chunk_array[2048]: item 0 key (FIRST_CHUNK_TREE CHUNK_ITEM 0) chunk length 4194304 owner 2 stripe_len 65536 type SYSTEM num_stripes 1 stripe 0 devid 1 offset 0 dev uuid: 08c50aa9-c2dd-43b7-a631-6dfdc7d69ea4 item 1 key (FIRST_CHUNK_TREE CHUNK_ITEM 20971520) chunk length 11010048 owner 2 stripe_len 65536 type SYSTEM|RAID6 num_stripes 6 stripe 0 devid 6 offset 1048576 dev uuid: 390a1fd8-cc6c-40e7-b0b5-88ca7dcbcc32 stripe 1 devid 5 offset 1048576 dev uuid: 2df974c5-9dde-4062-81e9-c6eeee13db62 stripe 2 devid 4 offset 1048576 dev uuid: dce3d159-721d-4859-9955-37a03769bb0d stripe 3 devid 3 offset 1048576 dev uuid: 6f7142db-824c-4791-a5b2-d6ce11c81c8f stripe 4 devid 2 offset 1048576 dev uuid: dc8760f1-2c54-4134-a9a7-a0ac2b7a9f1c stripe 5 devid 1 offset 20971520 dev uuid: 08c50aa9-c2dd-43b7-a631-6dfdc7d69ea4 backup_roots[4]: backup 0: backup_tree_root: 4844253364224 gen: 161473 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 backup_extent_root: 4844248121344 gen: 161473 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 backup_dev_root: 1411186688 gen: 156893 level: 1 backup_csum_root: 4844247793664 gen: 161473 level: 3 backup_total_bytes: 18003557892096 backup_bytes_used: 7110380077056 backup_num_devices: 6 backup 1: backup_tree_root: 4844272943104 gen: 161474 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 backup_extent_root: 4844268240896 gen: 161474 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 backup_dev_root: 1411186688 gen: 156893 level: 1 backup_csum_root: 4844254216192 gen: 161474 level: 3 backup_total_bytes: 18003557892096 backup_bytes_used: 7110395990016 backup_num_devices: 6 backup 2: backup_tree_root: 4844252168192 gen: 161471 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 backup_extent_root: 4844242698240 gen: 161471 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 backup_dev_root: 1411186688 gen: 156893 level: 1 backup_csum_root: 4844241764352 gen: 161471 level: 3 backup_total_bytes: 18003557892096 backup_bytes_used: 7110343888896 backup_num_devices: 6 backup 3: backup_tree_root: 4844263358464 gen: 161472 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 backup_extent_root: 4844261965824 gen: 161472 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 backup_dev_root: 1411186688 gen: 156893 level: 1 backup_csum_root: 4844261801984 gen: 161472 level: 3 backup_total_bytes: 18003557892096 backup_bytes_used: 7110370037760 backup_num_devices: 6 root@castor:~# btrfs-show-super -f /dev/sda > sda root@castor:~# btrfs-show-super -f /dev/sdh > sdh root@castor:~# diff -u sda sdh --- sda 2016-10-11 11:09:42.853170807 -0500 +++ sdh 2016-10-11 11:09:46.469082028 -0500 @@ -1,16 +1,16 @@ -superblock: bytenr=65536, device=/dev/sda +superblock: bytenr=65536, device=/dev/sdh --------------------------------------------------------- csum_type 0 (crc32c) csum_size 4 -csum 0x45278835 [match] +csum 0x0f7dfe09 [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 73ed01df-fb2a-4b27-b6fc-12a57da934bd label -generation 161562 -root 5752616386560 +generation 161474 +root 4844272943104 sys_array_size 354 chunk_root_generation 156893 root_level 1 @@ -20,7 +20,7 @@ log_root_transid 0 log_root_level 0 total_bytes 18003557892096 -bytes_used 7107627130880 +bytes_used 7110395990016 sectorsize 4096 nodesize 16384 leafsize 16384 @@ -34,17 +34,17 @@ BIG_METADATA | EXTENDED_IREF | RAID56 ) -cache_generation 161562 -uuid_tree_generation 161562 -dev_item.uuid 08c50aa9-c2dd-43b7-a631-6dfdc7d69ea4 +cache_generation 161474 +uuid_tree_generation 161474 +dev_item.uuid dc8760f1-2c54-4134-a9a7-a0ac2b7a9f1c dev_item.fsid 73ed01df-fb2a-4b27-b6fc-12a57da934bd [match] dev_item.type 0 dev_item.total_bytes 3000592982016 -dev_item.bytes_used 1800957198336 +dev_item.bytes_used 1800936226816 dev_item.io_align 4096 dev_item.io_width 4096 dev_item.sector_size 4096 -dev_item.devid 1 +dev_item.devid 2 dev_item.dev_group 0 dev_item.seek_speed 0 dev_item.bandwidth 0 @@ -72,47 +72,47 @@ dev uuid: 08c50aa9-c2dd-43b7-a631-6dfdc7d69ea4 backup_roots[4]: backup 0: - backup_tree_root: 5752437456896 gen: 161561 level: 1 + backup_tree_root: 4844253364224 gen: 161473 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 - backup_extent_root: 5752385224704 gen: 161561 level: 2 + backup_extent_root: 4844248121344 gen: 161473 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 - backup_dev_root: 5752437587968 gen: 161561 level: 1 - backup_csum_root: 5752389615616 gen: 161561 level: 3 + backup_dev_root: 1411186688 gen: 156893 level: 1 + backup_csum_root: 4844247793664 gen: 161473 level: 3 backup_total_bytes: 18003557892096 - backup_bytes_used: 7112579833856 + backup_bytes_used: 7110380077056 backup_num_devices: 6 backup 1: - backup_tree_root: 5752616386560 gen: 161562 level: 1 + backup_tree_root: 4844272943104 gen: 161474 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 - backup_extent_root: 5752649416704 gen: 161563 level: 2 + backup_extent_root: 4844268240896 gen: 161474 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 - backup_dev_root: 5752616501248 gen: 161562 level: 1 - backup_csum_root: 5752650203136 gen: 161563 level: 3 + backup_dev_root: 1411186688 gen: 156893 level: 1 + backup_csum_root: 4844254216192 gen: 161474 level: 3 backup_total_bytes: 18003557892096 - backup_bytes_used: 7107602407424 + backup_bytes_used: 7110395990016 backup_num_devices: 6 backup 2: - backup_tree_root: 5752112103424 gen: 161559 level: 1 + backup_tree_root: 4844252168192 gen: 161471 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 - backup_extent_root: 5752207409152 gen: 161560 level: 2 + backup_extent_root: 4844242698240 gen: 161471 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 - backup_dev_root: 5752113463296 gen: 161559 level: 1 - backup_csum_root: 5752205492224 gen: 161560 level: 3 + backup_dev_root: 1411186688 gen: 156893 level: 1 + backup_csum_root: 4844241764352 gen: 161471 level: 3 backup_total_bytes: 18003557892096 - backup_bytes_used: 7112514002944 + backup_bytes_used: 7110343888896 backup_num_devices: 6 backup 3: - backup_tree_root: 5752298307584 gen: 161560 level: 1 + backup_tree_root: 4844263358464 gen: 161472 level: 1 backup_chunk_root: 20971520 gen: 156893 level: 1 - backup_extent_root: 5752385224704 gen: 161561 level: 2 + backup_extent_root: 4844261965824 gen: 161472 level: 2 backup_fs_root: 124387328 gen: 74008 level: 0 - backup_dev_root: 5752299978752 gen: 161560 level: 1 - backup_csum_root: 5752389615616 gen: 161561 level: 3 + backup_dev_root: 1411186688 gen: 156893 level: 1 + backup_csum_root: 4844261801984 gen: 161472 level: 3 backup_total_bytes: 18003557892096 - backup_bytes_used: 7112542425088 + backup_bytes_used: 7110370037760 backup_num_devices: 6