* Re: Can't mount an encrypted backing device
[not found] ` <alpine.LRH.2.11.2001062258320.2074@mx.ewheeler.net>
@ 2020-01-11 13:42 ` Clodoaldo Neto
2020-01-16 22:55 ` Eric Wheeler
0 siblings, 1 reply; 15+ messages in thread
From: Clodoaldo Neto @ 2020-01-11 13:42 UTC (permalink / raw)
To: Eric Wheeler; +Cc: linux-bcache
On Mon, Jan 6, 2020 at 8:02 PM Eric Wheeler <bcache@lists.ewheeler.net> wrote:
>
> On Sun, 5 Jan 2020, Clodoaldo Neto wrote:
>
> > I'm struggling to mount an encrypted backing device. The backing
> > device is a RAID 1 array at /dev/md127 and the cache device is
> > /dev/sdb1.
> >
> > # lsblk
> > NAME MAJ:MIN RM SIZE RO
> > TYPE MOUNTPOINT
> > sda 8:0 0 223.6G 0 disk
> > ├─sda1 8:1 0 700M 0 part /boot
> > ├─sda2 8:2 0 700M 0
> > part /boot/efi
> > ├─sda3 8:3 0 26G 0 part
> > │ └─luks-9793c78f-723c-4218-865f-83dbc4659192 253:1 0 26G 0 crypt [SWAP]
> > └─sda4 8:4 0 162G 0 part
> > └─luks-569b1153-2fab-4984-b1b6-c4a02ee206ef 253:0 0 162G 0 crypt /
> > sdb 8:16 0 111.8G 0 disk
> > ├─sdb1 8:17 0 40G 0 part
> > └─sdb2 8:18 0 71.8G 0 part
> > sdc 8:32 0 1.8T 0 disk
> > └─sdc1 8:33 0 1.8T 0 part
> > └─md127 9:127 0 1.8T 0 raid1
> > sdd 8:48 0 1.8T 0 disk
> > └─sdd1 8:49 0 1.8T 0 part
> > └─md127 9:127 0 1.8T 0 raid1
> > sde 8:64 1 58.9G 0 disk
> > ├─sde1 8:65 1 20G 0 part
> > └─sde2 8:66 1 38.9G 0 part
> > sr0 11:0 1 1024M 0 rom
> >
> > # blkid | grep -E "md127|sdb1"
> > /dev/sdb1: UUID="535bfa2d-4c6e-4c19-91b2-d292872a1877" TYPE="bcache"
> > PARTLABEL="Linux filesystem"
> > PARTUUID="505789f1-0523-4c62-bdb1-81bc0cc7bff1"
> > /dev/md127: UUID="b17ceaac-27ec-44d8-8bbb-235cfaa0c4a4" TYPE="bcache"
> >
> > It was working right when I installed Fedora 31 yesterday but then I
> > resized the caching partition and I can't make it work again.
> >
> > This is what I tried
> >
> > # wipefs -a /dev/sdb1
> > /dev/sdb1: 16 bytes were erased at offset 0x00001018 (bcache): c6 85
> > 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
> >
> > # make-bcache -C --writeback /dev/sdb1
> > UUID: eb7d8e72-f24c-48ee-bad0-771afccca876
> > Set UUID: 50e33260-4623-4374-9a61-c78b7d75280e
> > version: 0
> > nbuckets: 81920
> > block_size: 1
> > bucket_size: 1024
> > nr_in_set: 1
> > nr_this_dev: 0
> > first_bucket: 1
> >
> > # ll /sys/fs/bcache/
> > total 0
> > drwxr-xr-x. 7 root root 0 Jan 5 18:34 50e33260-4623-4374-9a61-c78b7d75280e
> > --w-------. 1 root root 4096 Jan 5 17:39 pendings_cleanup
> > --w-------. 1 root root 4096 Jan 5 18:03 register
> > --w-------. 1 root root 4096 Jan 5 17:39 register_quiet
> >
> > # bcache-super-show /dev/sdb1
> > sb.magic ok
> > sb.first_sector 8 [match]
> > sb.csum C4CB62916B7825CE [match]
> > sb.version 3 [cache device]
> >
> > dev.label (empty)
> > dev.uuid eb7d8e72-f24c-48ee-bad0-771afccca876
> > dev.sectors_per_block 1
> > dev.sectors_per_bucket 1024
> > dev.cache.first_sector 1024
> > dev.cache.cache_sectors 83885056
> > dev.cache.total_sectors 83886080
> > dev.cache.ordered yes
> > dev.cache.discard no
> > dev.cache.pos 0
> > dev.cache.replacement 0 [lru]
> >
> > cset.uuid 50e33260-4623-4374-9a61-c78b7d75280e
> >
> > # echo /dev/md127 > /sys/fs/bcache/register
> > # echo 50e33260-4623-4374-9a61-c78b7d75280e > /sys/block/md127/bcache/attach
> > # blkid | grep bcache0
> > /dev/bcache0: UUID="7e2c0b40-8dec-4b13-8d00-b53b55160775" TYPE="crypto_LUKS"
> >
> > # bcache-status
> > --- bcache ---
> > UUID 50e33260-4623-4374-9a61-c78b7d75280e
> > Block Size 512 B
> > Bucket Size 512.00 KiB
> > Congested? False
> > Read Congestion 2.0ms
> > Write Congestion 20.0ms
> > Total Cache Size 40 GiB
> > Total Cache Used 409.6 MiB (1%)
> > Total Cache Unused 40 GiB (99%)
> > Evictable Cache 40 GiB (100%)
> > Replacement Policy [lru] fifo random
> > Cache Mode writethrough [writeback] writearound none
> > Total Hits 9 (64%)
> > Total Misses 5
> > Total Bypass Hits 13 (16%)
> > Total Bypass Misses 64
> > Total Bypassed 308.00 KiB
> >
> > # lsblk
> > NAME MAJ:MIN RM SIZE RO
> > TYPE MOUNTPOINT
> > sda 8:0 0 223.6G 0 disk
> > ├─sda1 8:1 0 700M 0 part /boot
> > ├─sda2 8:2 0 700M 0
> > part /boot/efi
> > ├─sda3 8:3 0 26G 0 part
> > │ └─luks-9793c78f-723c-4218-865f-83dbc4659192 253:1 0 26G 0 crypt [SWAP]
> > └─sda4 8:4 0 162G 0 part
> > └─luks-569b1153-2fab-4984-b1b6-c4a02ee206ef 253:0 0 162G 0 crypt /
> > sdb 8:16 0 111.8G 0 disk
> > ├─sdb1 8:17 0 40G 0 part
> > │ └─bcache0 252:0 0 1.8T 0 disk
> > └─sdb2 8:18 0 71.8G 0 part
> > sdc 8:32 0 1.8T 0 disk
> > └─sdc1 8:33 0 1.8T 0 part
> > └─md127 9:127 0 1.8T 0 raid1
> > └─bcache0 252:0 0 1.8T 0 disk
> > sdd 8:48 0 1.8T 0 disk
> > └─sdd1 8:49 0 1.8T 0 part
> > └─md127 9:127 0 1.8T 0 raid1
> > └─bcache0 252:0 0 1.8T 0 disk
> > sde 8:64 1 58.9G 0 disk
> > ├─sde1 8:65 1 20G 0 part
> > └─sde2 8:66 1 38.9G 0 part
> > sr0 11:0 1 1024M 0 rom
> >
> > # mount /dev/bcache0 /r
> > mount: /r: unknown filesystem type 'crypto_LUKS'.
> >
> > # cryptsetup open /dev/bcache0 backing-device
> > Enter passphrase for /dev/bcache0:
> >
> > # mount /dev/mapper/backing-device /r
> > mount: /r: unknown filesystem type 'bcache'.
>
> I'm guessing that make-bcache was run upon /dev/mapper/backing-device at
> some point in time. Hopefully it wasn't clobbered.
>
I guess you are right because /dev/mapper/backing-device is seen as a
cache device:
# bcache-super-show /dev/mapper/backing-device
sb.magic ok
sb.first_sector 8 [match]
sb.csum D9C2336DD00A6E69 [match]
sb.version 3 [cache device]
dev.label (empty)
dev.uuid 8022eea3-fcf0-40b8-850a-31e5f841d0bd
dev.sectors_per_block 1
dev.sectors_per_bucket 1024
dev.cache.first_sector 1024
dev.cache.cache_sectors 3774576640
dev.cache.total_sectors 3774577664
dev.cache.ordered yes
dev.cache.discard no
dev.cache.pos 0
dev.cache.replacement 0 [lru]
cset.uuid 4a63d2b5-1568-473d-925d-53306af2ba7c
Is there a path to revert it? Like just formatting it to ext4?
> Try
>
> mount -t ext2 /dev/mapper/backing-device /r
> ^^^^ or whatever your original FS really was.
>
# mount /dev/mapper/backing-device /r
mount: /r: unknown filesystem type 'bcache'.
> --
> Eric Wheeler
>
>
> >
> > What am I missing?
> >
> > Regards, Clodoaldo
> >
^ permalink raw reply [flat|nested] 15+ messages in thread
* undo make-bcache (was: Re: Can't mount an encrypted backing device)
[not found] ` <65c05b80-679b-2ccb-1bd1-a9a6887c9c51@suse.de>
@ 2020-01-13 12:44 ` Jens-U. Mozdzen
2020-01-13 14:18 ` Coly Li
0 siblings, 1 reply; 15+ messages in thread
From: Jens-U. Mozdzen @ 2020-01-13 12:44 UTC (permalink / raw)
To: Coly Li; +Cc: linux-bcache
Hi Coly,
jumping in here, because I was looking for a way to revert from bcache
to plain device:
Zitat von Coly Li <colyli@suse.de>:
> The super block location of the backing disk is occupied by bcache. You
> cannot mount the file system directly from the backing disk which is
> formated as bcache backing device [...] (bcache offset all I/Os on
> bcache device 4KB behind the requesting
> LBA on backing disk).
Assuming that no caching device is associated with a backing device
(so the backing device is "clean" as in "containing all data blocks
with the current content"), could one convert the content of a backing
device to a "non-bcached device" by removing the first 4096 octets of
the backing device content?
Something like "dd if=backingdev of=newdev skip_bytes=4096 ..."?
Regards,
J
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: undo make-bcache (was: Re: Can't mount an encrypted backing device)
2020-01-13 12:44 ` undo make-bcache (was: Re: Can't mount an encrypted backing device) Jens-U. Mozdzen
@ 2020-01-13 14:18 ` Coly Li
[not found] ` <CA+Z73LGG1pBtT=0WN5vEyqEvzxEnqMRZ26S_2x4Gd5JPSmuXmQ@mail.gmail.com>
0 siblings, 1 reply; 15+ messages in thread
From: Coly Li @ 2020-01-13 14:18 UTC (permalink / raw)
To: Jens-U. Mozdzen; +Cc: linux-bcache
On 2020/1/13 8:44 下午, Jens-U. Mozdzen wrote:
> Hi Coly,
>
> jumping in here, because I was looking for a way to revert from bcache
> to plain device:
>
> Zitat von Coly Li <colyli@suse.de>:
>> The super block location of the backing disk is occupied by bcache. You
>> cannot mount the file system directly from the backing disk which is
>> formated as bcache backing device [...] (bcache offset all I/Os on
>> bcache device 4KB behind the requesting
>> LBA on backing disk).
>
> Assuming that no caching device is associated with a backing device (so
> the backing device is "clean" as in "containing all data blocks with the
> current content"), could one convert the content of a backing device to
> a "non-bcached device" by removing the first 4096 octets of the backing
> device content?
>
> Something like "dd if=backingdev of=newdev skip_bytes=4096 ..."?
Hi Jens-U,
you may try dmsetup to setup a linear device mapper target, and the map
table just skipping the first 4KB (bcache superblock area). If you are
lucky, I mean the real file system is not corrupted, the created device
mapper target can be mounted directly.
--
Coly Li
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: undo make-bcache (was: Re: Can't mount an encrypted backing device)
[not found] ` <CA+Z73LGXJOwYEb+GmPuuDi3TcJbGG=NLv-5vCRcEvB+kgr4a+A@mail.gmail.com>
@ 2020-01-16 21:56 ` Clodoaldo Neto
2020-01-16 23:00 ` Eric Wheeler
2020-01-17 0:58 ` Coly Li
1 sibling, 1 reply; 15+ messages in thread
From: Clodoaldo Neto @ 2020-01-16 21:56 UTC (permalink / raw)
To: linux-bcache
Em seg, 13 de jan de 2020 11:19, Coly Li <colyli@suse.de> escreveu:
>
> On 2020/1/13 8:44 下午, Jens-U. Mozdzen wrote:
> > Hi Coly,
> >
> > jumping in here, because I was looking for a way to revert from bcache
> > to plain device:
> >
> > Zitat von Coly Li <colyli@suse.de>:
> >> The super block location of the backing disk is occupied by bcache. You
> >> cannot mount the file system directly from the backing disk which is
> >> formated as bcache backing device [...] (bcache offset all I/Os on
> >> bcache device 4KB behind the requesting
> >> LBA on backing disk).
> >
> > Assuming that no caching device is associated with a backing device (so
> > the backing device is "clean" as in "containing all data blocks with the
> > current content"), could one convert the content of a backing device to
> > a "non-bcached device" by removing the first 4096 octets of the backing
> > device content?
> >
> > Something like "dd if=backingdev of=newdev skip_bytes=4096 ..."?
>
> Hi Jens-U,
>
> you may try dmsetup to setup a linear device mapper target, and the map
> table just skipping the first 4KB (bcache superblock area). If you are
> lucky, I mean the real file system is not corrupted, the created device
> mapper target can be mounted directly.
I'm trying dmsetup but it does not accept anything other than 0 and 0
at the beginning and end of the table:
# echo '0 3774578672 linear /dev/mapper/backing-device 8' | dmsetup create dmb
device-mapper: reload ioctl on dmb failed: Invalid argument
Command failed.
# echo '8 3774578664 linear /dev/mapper/backing-device 0' | dmsetup create dmb
device-mapper: reload ioctl on dmb failed: Invalid argument
Command failed.
I'm not sure about how it works. Is it not 8 sectors for 4k bytes?
Clodoaldo
>
> --
>
> Coly Li
>
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: Can't mount an encrypted backing device
2020-01-11 13:42 ` Can't mount an encrypted backing device Clodoaldo Neto
@ 2020-01-16 22:55 ` Eric Wheeler
2020-01-18 10:44 ` Clodoaldo Neto
0 siblings, 1 reply; 15+ messages in thread
From: Eric Wheeler @ 2020-01-16 22:55 UTC (permalink / raw)
To: Clodoaldo Neto; +Cc: linux-bcache
[-- Attachment #1: Type: TEXT/PLAIN, Size: 9068 bytes --]
On Sat, 11 Jan 2020, Clodoaldo Neto wrote:
> On Mon, Jan 6, 2020 at 8:02 PM Eric Wheeler <bcache@lists.ewheeler.net> wrote:
> >
> > On Sun, 5 Jan 2020, Clodoaldo Neto wrote:
> >
> > > I'm struggling to mount an encrypted backing device. The backing
> > > device is a RAID 1 array at /dev/md127 and the cache device is
> > > /dev/sdb1.
> > >
> > > # lsblk
> > > NAME MAJ:MIN RM SIZE RO
> > > TYPE MOUNTPOINT
> > > sda 8:0 0 223.6G 0 disk
> > > ├─sda1 8:1 0 700M 0 part /boot
> > > ├─sda2 8:2 0 700M 0
> > > part /boot/efi
> > > ├─sda3 8:3 0 26G 0 part
> > > │ └─luks-9793c78f-723c-4218-865f-83dbc4659192 253:1 0 26G 0 crypt [SWAP]
> > > └─sda4 8:4 0 162G 0 part
> > > └─luks-569b1153-2fab-4984-b1b6-c4a02ee206ef 253:0 0 162G 0 crypt /
> > > sdb 8:16 0 111.8G 0 disk
> > > ├─sdb1 8:17 0 40G 0 part
> > > └─sdb2 8:18 0 71.8G 0 part
> > > sdc 8:32 0 1.8T 0 disk
> > > └─sdc1 8:33 0 1.8T 0 part
> > > └─md127 9:127 0 1.8T 0 raid1
> > > sdd 8:48 0 1.8T 0 disk
> > > └─sdd1 8:49 0 1.8T 0 part
> > > └─md127 9:127 0 1.8T 0 raid1
> > > sde 8:64 1 58.9G 0 disk
> > > ├─sde1 8:65 1 20G 0 part
> > > └─sde2 8:66 1 38.9G 0 part
> > > sr0 11:0 1 1024M 0 rom
> > >
> > > # blkid | grep -E "md127|sdb1"
> > > /dev/sdb1: UUID="535bfa2d-4c6e-4c19-91b2-d292872a1877" TYPE="bcache"
> > > PARTLABEL="Linux filesystem"
> > > PARTUUID="505789f1-0523-4c62-bdb1-81bc0cc7bff1"
> > > /dev/md127: UUID="b17ceaac-27ec-44d8-8bbb-235cfaa0c4a4" TYPE="bcache"
> > >
> > > It was working right when I installed Fedora 31 yesterday but then I
> > > resized the caching partition and I can't make it work again.
> > >
> > > This is what I tried
> > >
> > > # wipefs -a /dev/sdb1
> > > /dev/sdb1: 16 bytes were erased at offset 0x00001018 (bcache): c6 85
> > > 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
> > >
> > > # make-bcache -C --writeback /dev/sdb1
> > > UUID: eb7d8e72-f24c-48ee-bad0-771afccca876
> > > Set UUID: 50e33260-4623-4374-9a61-c78b7d75280e
> > > version: 0
> > > nbuckets: 81920
> > > block_size: 1
> > > bucket_size: 1024
> > > nr_in_set: 1
> > > nr_this_dev: 0
> > > first_bucket: 1
> > >
> > > # ll /sys/fs/bcache/
> > > total 0
> > > drwxr-xr-x. 7 root root 0 Jan 5 18:34 50e33260-4623-4374-9a61-c78b7d75280e
> > > --w-------. 1 root root 4096 Jan 5 17:39 pendings_cleanup
> > > --w-------. 1 root root 4096 Jan 5 18:03 register
> > > --w-------. 1 root root 4096 Jan 5 17:39 register_quiet
> > >
> > > # bcache-super-show /dev/sdb1
> > > sb.magic ok
> > > sb.first_sector 8 [match]
> > > sb.csum C4CB62916B7825CE [match]
> > > sb.version 3 [cache device]
> > >
> > > dev.label (empty)
> > > dev.uuid eb7d8e72-f24c-48ee-bad0-771afccca876
> > > dev.sectors_per_block 1
> > > dev.sectors_per_bucket 1024
> > > dev.cache.first_sector 1024
> > > dev.cache.cache_sectors 83885056
> > > dev.cache.total_sectors 83886080
> > > dev.cache.ordered yes
> > > dev.cache.discard no
> > > dev.cache.pos 0
> > > dev.cache.replacement 0 [lru]
> > >
> > > cset.uuid 50e33260-4623-4374-9a61-c78b7d75280e
> > >
> > > # echo /dev/md127 > /sys/fs/bcache/register
> > > # echo 50e33260-4623-4374-9a61-c78b7d75280e > /sys/block/md127/bcache/attach
> > > # blkid | grep bcache0
> > > /dev/bcache0: UUID="7e2c0b40-8dec-4b13-8d00-b53b55160775" TYPE="crypto_LUKS"
> > >
> > > # bcache-status
> > > --- bcache ---
> > > UUID 50e33260-4623-4374-9a61-c78b7d75280e
> > > Block Size 512 B
> > > Bucket Size 512.00 KiB
> > > Congested? False
> > > Read Congestion 2.0ms
> > > Write Congestion 20.0ms
> > > Total Cache Size 40 GiB
> > > Total Cache Used 409.6 MiB (1%)
> > > Total Cache Unused 40 GiB (99%)
> > > Evictable Cache 40 GiB (100%)
> > > Replacement Policy [lru] fifo random
> > > Cache Mode writethrough [writeback] writearound none
> > > Total Hits 9 (64%)
> > > Total Misses 5
> > > Total Bypass Hits 13 (16%)
> > > Total Bypass Misses 64
> > > Total Bypassed 308.00 KiB
> > >
> > > # lsblk
> > > NAME MAJ:MIN RM SIZE RO
> > > TYPE MOUNTPOINT
> > > sda 8:0 0 223.6G 0 disk
> > > ├─sda1 8:1 0 700M 0 part /boot
> > > ├─sda2 8:2 0 700M 0
> > > part /boot/efi
> > > ├─sda3 8:3 0 26G 0 part
> > > │ └─luks-9793c78f-723c-4218-865f-83dbc4659192 253:1 0 26G 0 crypt [SWAP]
> > > └─sda4 8:4 0 162G 0 part
> > > └─luks-569b1153-2fab-4984-b1b6-c4a02ee206ef 253:0 0 162G 0 crypt /
> > > sdb 8:16 0 111.8G 0 disk
> > > ├─sdb1 8:17 0 40G 0 part
> > > │ └─bcache0 252:0 0 1.8T 0 disk
> > > └─sdb2 8:18 0 71.8G 0 part
> > > sdc 8:32 0 1.8T 0 disk
> > > └─sdc1 8:33 0 1.8T 0 part
> > > └─md127 9:127 0 1.8T 0 raid1
> > > └─bcache0 252:0 0 1.8T 0 disk
> > > sdd 8:48 0 1.8T 0 disk
> > > └─sdd1 8:49 0 1.8T 0 part
> > > └─md127 9:127 0 1.8T 0 raid1
> > > └─bcache0 252:0 0 1.8T 0 disk
> > > sde 8:64 1 58.9G 0 disk
> > > ├─sde1 8:65 1 20G 0 part
> > > └─sde2 8:66 1 38.9G 0 part
> > > sr0 11:0 1 1024M 0 rom
> > >
> > > # mount /dev/bcache0 /r
> > > mount: /r: unknown filesystem type 'crypto_LUKS'.
> > >
> > > # cryptsetup open /dev/bcache0 backing-device
> > > Enter passphrase for /dev/bcache0:
> > >
> > > # mount /dev/mapper/backing-device /r
> > > mount: /r: unknown filesystem type 'bcache'.
> >
> > I'm guessing that make-bcache was run upon /dev/mapper/backing-device at
> > some point in time. Hopefully it wasn't clobbered.
> >
> I guess you are right because /dev/mapper/backing-device is seen as a
> cache device:
>
> # bcache-super-show /dev/mapper/backing-device
> sb.magic ok
> sb.first_sector 8 [match]
> sb.csum D9C2336DD00A6E69 [match]
> sb.version 3 [cache device]
>
> dev.label (empty)
> dev.uuid 8022eea3-fcf0-40b8-850a-31e5f841d0bd
> dev.sectors_per_block 1
> dev.sectors_per_bucket 1024
> dev.cache.first_sector 1024
> dev.cache.cache_sectors 3774576640
> dev.cache.total_sectors 3774577664
> dev.cache.ordered yes
> dev.cache.discard no
> dev.cache.pos 0
> dev.cache.replacement 0 [lru]
>
> cset.uuid 4a63d2b5-1568-473d-925d-53306af2ba7c
>
> Is there a path to revert it? Like just formatting it to ext4?
>
> > Try
> >
> > mount -t ext2 /dev/mapper/backing-device /r
> > ^^^^ or whatever your original FS really was.
> >
> # mount /dev/mapper/backing-device /r
> mount: /r: unknown filesystem type 'bcache'.
I don't see a -t option to mount. Does it work with -t ?
If not, and if the cache device is gone forever, you could try this to
force the device online:
echo 1 > /sys/block/bcache0/bcache/run
> > --
> > Eric Wheeler
> >
> >
> > >
> > > What am I missing?
> > >
> > > Regards, Clodoaldo
> > >
>
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: undo make-bcache (was: Re: Can't mount an encrypted backing device)
2020-01-16 21:56 ` Clodoaldo Neto
@ 2020-01-16 23:00 ` Eric Wheeler
2020-01-18 11:44 ` Clodoaldo Neto
0 siblings, 1 reply; 15+ messages in thread
From: Eric Wheeler @ 2020-01-16 23:00 UTC (permalink / raw)
To: Clodoaldo Neto; +Cc: linux-bcache
[-- Attachment #1: Type: TEXT/PLAIN, Size: 1902 bytes --]
On Thu, 16 Jan 2020, Clodoaldo Neto wrote:
> Em seg, 13 de jan de 2020 11:19, Coly Li <colyli@suse.de> escreveu:
> >
> > On 2020/1/13 8:44 下午, Jens-U. Mozdzen wrote:
> > > Hi Coly,
> > >
> > > jumping in here, because I was looking for a way to revert from bcache
> > > to plain device:
> > >
> > > Zitat von Coly Li <colyli@suse.de>:
> > >> The super block location of the backing disk is occupied by bcache. You
> > >> cannot mount the file system directly from the backing disk which is
> > >> formated as bcache backing device [...] (bcache offset all I/Os on
> > >> bcache device 4KB behind the requesting
> > >> LBA on backing disk).
> > >
> > > Assuming that no caching device is associated with a backing device (so
> > > the backing device is "clean" as in "containing all data blocks with the
> > > current content"), could one convert the content of a backing device to
> > > a "non-bcached device" by removing the first 4096 octets of the backing
> > > device content?
> > >
> > > Something like "dd if=backingdev of=newdev skip_bytes=4096 ..."?
> >
> > Hi Jens-U,
> >
> > you may try dmsetup to setup a linear device mapper target, and the map
> > table just skipping the first 4KB (bcache superblock area). If you are
> > lucky, I mean the real file system is not corrupted, the created device
> > mapper target can be mounted directly.
>
>
> I'm trying dmsetup but it does not accept anything other than 0 and 0
> at the beginning and end of the table:
>
> # echo '0 3774578672 linear /dev/mapper/backing-device 8' | dmsetup create dmb
> device-mapper: reload ioctl on dmb failed: Invalid argument
> Command failed.
>
> # echo '8 3774578664 linear /dev/mapper/backing-device 0' | dmsetup create dmb
> device-mapper: reload ioctl on dmb failed: Invalid argument
> Command failed.
>
> I'm not sure about how it works. Is it not 8 sectors for 4k bytes?
Does dmesg give a hint?
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: undo make-bcache (was: Re: Can't mount an encrypted backing device)
[not found] ` <CA+Z73LGXJOwYEb+GmPuuDi3TcJbGG=NLv-5vCRcEvB+kgr4a+A@mail.gmail.com>
2020-01-16 21:56 ` Clodoaldo Neto
@ 2020-01-17 0:58 ` Coly Li
2020-01-18 10:54 ` Clodoaldo Neto
1 sibling, 1 reply; 15+ messages in thread
From: Coly Li @ 2020-01-17 0:58 UTC (permalink / raw)
To: clodoaldo.pinto.neto; +Cc: Jens-U. Mozdzen, linux-bcache
On 2020/1/17 5:52 上午, Clodoaldo Neto wrote:
>
> Em seg, 13 de jan de 2020 11:19, Coly Li <colyli@suse.de
> <mailto:colyli@suse.de>> escreveu:
>>
>> On 2020/1/13 8:44 下午, Jens-U. Mozdzen wrote:
>> > Hi Coly,
>> >
>> > jumping in here, because I was looking for a way to revert from bcache
>> > to plain device:
>> >
>> > Zitat von Coly Li <colyli@suse.de <mailto:colyli@suse.de>>:
>> >> The super block location of the backing disk is occupied by bcache. You
>> >> cannot mount the file system directly from the backing disk which is
>> >> formated as bcache backing device [...] (bcache offset all I/Os on
>> >> bcache device 4KB behind the requesting
>> >> LBA on backing disk).
>> >
>> > Assuming that no caching device is associated with a backing device (so
>> > the backing device is "clean" as in "containing all data blocks with the
>> > current content"), could one convert the content of a backing device to
>> > a "non-bcached device" by removing the first 4096 octets of the backing
>> > device content?
>> >
>> > Something like "dd if=backingdev of=newdev skip_bytes=4096 ..."?
>>
>> Hi Jens-U,
>>
>> you may try dmsetup to setup a linear device mapper target, and the map
>> table just skipping the first 4KB (bcache superblock area). If you are
>> lucky, I mean the real file system is not corrupted, the created device
>> mapper target can be mounted directly.
>
>
> I'm trying dmsetup but it does not accept anything other than 0 and 0
> at the beginning and end of the table:
>
> # echo '0 3774578672 linear /dev/mapper/backing-device 8' | dmsetup
> create dmb
> device-mapper: reload ioctl on dmb failed: Invalid argument
> Command failed.
The above line should work, if 3774578672 is a correct size number in
sectors.
>
> # echo '8 3774578664 linear /dev/mapper/backing-device 0' | dmsetup
> create dmb
> device-mapper: reload ioctl on dmb failed: Invalid argument
> Command failed.
>
> I'm not sure about how it works. Is it not 8 sectors for 4k bytes?
>
It works on my side, my kernel is Linux v5.5-rc2, lvm2 version is
2.02.180, dmsetup version is 1.02.149. The difference is the device
size, my disk size is much less.
--
Coly Li
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: Can't mount an encrypted backing device
2020-01-16 22:55 ` Eric Wheeler
@ 2020-01-18 10:44 ` Clodoaldo Neto
0 siblings, 0 replies; 15+ messages in thread
From: Clodoaldo Neto @ 2020-01-18 10:44 UTC (permalink / raw)
To: Eric Wheeler; +Cc: linux-bcache
On Thu, Jan 16, 2020 at 7:55 PM Eric Wheeler <bcache@lists.ewheeler.net> wrote:
>
> On Sat, 11 Jan 2020, Clodoaldo Neto wrote:
>
> > On Mon, Jan 6, 2020 at 8:02 PM Eric Wheeler <bcache@lists.ewheeler.net> wrote:
> > >
> > > On Sun, 5 Jan 2020, Clodoaldo Neto wrote:
> > >
> > > > I'm struggling to mount an encrypted backing device. The backing
> > > > device is a RAID 1 array at /dev/md127 and the cache device is
> > > > /dev/sdb1.
> > > >
> > > > # lsblk
> > > > NAME MAJ:MIN RM SIZE RO
> > > > TYPE MOUNTPOINT
> > > > sda 8:0 0 223.6G 0 disk
> > > > ├─sda1 8:1 0 700M 0 part /boot
> > > > ├─sda2 8:2 0 700M 0
> > > > part /boot/efi
> > > > ├─sda3 8:3 0 26G 0 part
> > > > │ └─luks-9793c78f-723c-4218-865f-83dbc4659192 253:1 0 26G 0 crypt [SWAP]
> > > > └─sda4 8:4 0 162G 0 part
> > > > └─luks-569b1153-2fab-4984-b1b6-c4a02ee206ef 253:0 0 162G 0 crypt /
> > > > sdb 8:16 0 111.8G 0 disk
> > > > ├─sdb1 8:17 0 40G 0 part
> > > > └─sdb2 8:18 0 71.8G 0 part
> > > > sdc 8:32 0 1.8T 0 disk
> > > > └─sdc1 8:33 0 1.8T 0 part
> > > > └─md127 9:127 0 1.8T 0 raid1
> > > > sdd 8:48 0 1.8T 0 disk
> > > > └─sdd1 8:49 0 1.8T 0 part
> > > > └─md127 9:127 0 1.8T 0 raid1
> > > > sde 8:64 1 58.9G 0 disk
> > > > ├─sde1 8:65 1 20G 0 part
> > > > └─sde2 8:66 1 38.9G 0 part
> > > > sr0 11:0 1 1024M 0 rom
> > > >
> > > > # blkid | grep -E "md127|sdb1"
> > > > /dev/sdb1: UUID="535bfa2d-4c6e-4c19-91b2-d292872a1877" TYPE="bcache"
> > > > PARTLABEL="Linux filesystem"
> > > > PARTUUID="505789f1-0523-4c62-bdb1-81bc0cc7bff1"
> > > > /dev/md127: UUID="b17ceaac-27ec-44d8-8bbb-235cfaa0c4a4" TYPE="bcache"
> > > >
> > > > It was working right when I installed Fedora 31 yesterday but then I
> > > > resized the caching partition and I can't make it work again.
> > > >
> > > > This is what I tried
> > > >
> > > > # wipefs -a /dev/sdb1
> > > > /dev/sdb1: 16 bytes were erased at offset 0x00001018 (bcache): c6 85
> > > > 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
> > > >
> > > > # make-bcache -C --writeback /dev/sdb1
> > > > UUID: eb7d8e72-f24c-48ee-bad0-771afccca876
> > > > Set UUID: 50e33260-4623-4374-9a61-c78b7d75280e
> > > > version: 0
> > > > nbuckets: 81920
> > > > block_size: 1
> > > > bucket_size: 1024
> > > > nr_in_set: 1
> > > > nr_this_dev: 0
> > > > first_bucket: 1
> > > >
> > > > # ll /sys/fs/bcache/
> > > > total 0
> > > > drwxr-xr-x. 7 root root 0 Jan 5 18:34 50e33260-4623-4374-9a61-c78b7d75280e
> > > > --w-------. 1 root root 4096 Jan 5 17:39 pendings_cleanup
> > > > --w-------. 1 root root 4096 Jan 5 18:03 register
> > > > --w-------. 1 root root 4096 Jan 5 17:39 register_quiet
> > > >
> > > > # bcache-super-show /dev/sdb1
> > > > sb.magic ok
> > > > sb.first_sector 8 [match]
> > > > sb.csum C4CB62916B7825CE [match]
> > > > sb.version 3 [cache device]
> > > >
> > > > dev.label (empty)
> > > > dev.uuid eb7d8e72-f24c-48ee-bad0-771afccca876
> > > > dev.sectors_per_block 1
> > > > dev.sectors_per_bucket 1024
> > > > dev.cache.first_sector 1024
> > > > dev.cache.cache_sectors 83885056
> > > > dev.cache.total_sectors 83886080
> > > > dev.cache.ordered yes
> > > > dev.cache.discard no
> > > > dev.cache.pos 0
> > > > dev.cache.replacement 0 [lru]
> > > >
> > > > cset.uuid 50e33260-4623-4374-9a61-c78b7d75280e
> > > >
> > > > # echo /dev/md127 > /sys/fs/bcache/register
> > > > # echo 50e33260-4623-4374-9a61-c78b7d75280e > /sys/block/md127/bcache/attach
> > > > # blkid | grep bcache0
> > > > /dev/bcache0: UUID="7e2c0b40-8dec-4b13-8d00-b53b55160775" TYPE="crypto_LUKS"
> > > >
> > > > # bcache-status
> > > > --- bcache ---
> > > > UUID 50e33260-4623-4374-9a61-c78b7d75280e
> > > > Block Size 512 B
> > > > Bucket Size 512.00 KiB
> > > > Congested? False
> > > > Read Congestion 2.0ms
> > > > Write Congestion 20.0ms
> > > > Total Cache Size 40 GiB
> > > > Total Cache Used 409.6 MiB (1%)
> > > > Total Cache Unused 40 GiB (99%)
> > > > Evictable Cache 40 GiB (100%)
> > > > Replacement Policy [lru] fifo random
> > > > Cache Mode writethrough [writeback] writearound none
> > > > Total Hits 9 (64%)
> > > > Total Misses 5
> > > > Total Bypass Hits 13 (16%)
> > > > Total Bypass Misses 64
> > > > Total Bypassed 308.00 KiB
> > > >
> > > > # lsblk
> > > > NAME MAJ:MIN RM SIZE RO
> > > > TYPE MOUNTPOINT
> > > > sda 8:0 0 223.6G 0 disk
> > > > ├─sda1 8:1 0 700M 0 part /boot
> > > > ├─sda2 8:2 0 700M 0
> > > > part /boot/efi
> > > > ├─sda3 8:3 0 26G 0 part
> > > > │ └─luks-9793c78f-723c-4218-865f-83dbc4659192 253:1 0 26G 0 crypt [SWAP]
> > > > └─sda4 8:4 0 162G 0 part
> > > > └─luks-569b1153-2fab-4984-b1b6-c4a02ee206ef 253:0 0 162G 0 crypt /
> > > > sdb 8:16 0 111.8G 0 disk
> > > > ├─sdb1 8:17 0 40G 0 part
> > > > │ └─bcache0 252:0 0 1.8T 0 disk
> > > > └─sdb2 8:18 0 71.8G 0 part
> > > > sdc 8:32 0 1.8T 0 disk
> > > > └─sdc1 8:33 0 1.8T 0 part
> > > > └─md127 9:127 0 1.8T 0 raid1
> > > > └─bcache0 252:0 0 1.8T 0 disk
> > > > sdd 8:48 0 1.8T 0 disk
> > > > └─sdd1 8:49 0 1.8T 0 part
> > > > └─md127 9:127 0 1.8T 0 raid1
> > > > └─bcache0 252:0 0 1.8T 0 disk
> > > > sde 8:64 1 58.9G 0 disk
> > > > ├─sde1 8:65 1 20G 0 part
> > > > └─sde2 8:66 1 38.9G 0 part
> > > > sr0 11:0 1 1024M 0 rom
> > > >
> > > > # mount /dev/bcache0 /r
> > > > mount: /r: unknown filesystem type 'crypto_LUKS'.
> > > >
> > > > # cryptsetup open /dev/bcache0 backing-device
> > > > Enter passphrase for /dev/bcache0:
> > > >
> > > > # mount /dev/mapper/backing-device /r
> > > > mount: /r: unknown filesystem type 'bcache'.
> > >
> > > I'm guessing that make-bcache was run upon /dev/mapper/backing-device at
> > > some point in time. Hopefully it wasn't clobbered.
> > >
> > I guess you are right because /dev/mapper/backing-device is seen as a
> > cache device:
> >
> > # bcache-super-show /dev/mapper/backing-device
> > sb.magic ok
> > sb.first_sector 8 [match]
> > sb.csum D9C2336DD00A6E69 [match]
> > sb.version 3 [cache device]
> >
> > dev.label (empty)
> > dev.uuid 8022eea3-fcf0-40b8-850a-31e5f841d0bd
> > dev.sectors_per_block 1
> > dev.sectors_per_bucket 1024
> > dev.cache.first_sector 1024
> > dev.cache.cache_sectors 3774576640
> > dev.cache.total_sectors 3774577664
> > dev.cache.ordered yes
> > dev.cache.discard no
> > dev.cache.pos 0
> > dev.cache.replacement 0 [lru]
> >
> > cset.uuid 4a63d2b5-1568-473d-925d-53306af2ba7c
> >
> > Is there a path to revert it? Like just formatting it to ext4?
> >
> > > Try
> > >
> > > mount -t ext2 /dev/mapper/backing-device /r
> > > ^^^^ or whatever your original FS really was.
> > >
> > # mount /dev/mapper/backing-device /r
> > mount: /r: unknown filesystem type 'bcache'.
>
> I don't see a -t option to mount. Does it work with -t ?
# mount -t ext4 /dev/mapper/backing-device /r
mount: /r: wrong fs type, bad option, bad superblock on
/dev/mapper/backing-device, missing codepage or helper program, or
other error.
>
> If not, and if the cache device is gone forever, you could try this to
> force the device online:
>
> echo 1 > /sys/block/bcache0/bcache/run
>
I will reserve it for later
> > > --
> > > Eric Wheeler
> > >
> > >
> > > >
> > > > What am I missing?
> > > >
> > > > Regards, Clodoaldo
> > > >
> >
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: undo make-bcache (was: Re: Can't mount an encrypted backing device)
2020-01-17 0:58 ` Coly Li
@ 2020-01-18 10:54 ` Clodoaldo Neto
2020-01-18 12:22 ` Clodoaldo Neto
0 siblings, 1 reply; 15+ messages in thread
From: Clodoaldo Neto @ 2020-01-18 10:54 UTC (permalink / raw)
To: Coly Li; +Cc: Jens-U. Mozdzen, linux-bcache
On Thu, Jan 16, 2020 at 9:59 PM Coly Li <colyli@suse.de> wrote:
>
> On 2020/1/17 5:52 上午, Clodoaldo Neto wrote:
> >
> > Em seg, 13 de jan de 2020 11:19, Coly Li <colyli@suse.de
> > <mailto:colyli@suse.de>> escreveu:
> >>
> >> On 2020/1/13 8:44 下午, Jens-U. Mozdzen wrote:
> >> > Hi Coly,
> >> >
> >> > jumping in here, because I was looking for a way to revert from bcache
> >> > to plain device:
> >> >
> >> > Zitat von Coly Li <colyli@suse.de <mailto:colyli@suse.de>>:
> >> >> The super block location of the backing disk is occupied by bcache. You
> >> >> cannot mount the file system directly from the backing disk which is
> >> >> formated as bcache backing device [...] (bcache offset all I/Os on
> >> >> bcache device 4KB behind the requesting
> >> >> LBA on backing disk).
> >> >
> >> > Assuming that no caching device is associated with a backing device (so
> >> > the backing device is "clean" as in "containing all data blocks with the
> >> > current content"), could one convert the content of a backing device to
> >> > a "non-bcached device" by removing the first 4096 octets of the backing
> >> > device content?
> >> >
> >> > Something like "dd if=backingdev of=newdev skip_bytes=4096 ..."?
> >>
> >> Hi Jens-U,
> >>
> >> you may try dmsetup to setup a linear device mapper target, and the map
> >> table just skipping the first 4KB (bcache superblock area). If you are
> >> lucky, I mean the real file system is not corrupted, the created device
> >> mapper target can be mounted directly.
> >
> >
> > I'm trying dmsetup but it does not accept anything other than 0 and 0
> > at the beginning and end of the table:
> >
> > # echo '0 3774578672 linear /dev/mapper/backing-device 8' | dmsetup
> > create dmb
> > device-mapper: reload ioctl on dmb failed: Invalid argument
> > Command failed.
>
> The above line should work, if 3774578672 is a correct size number in
> sectors.
I took it from the original map:
# dmsetup table /dev/mapper/backing-device
0 3774578672 crypt aes-xts-plain64
:64:logon:cryptsetup:7e2c0b40-8dec-4b13-8d00-b53b55160775-d0 0 251:0
32768
>
> >
> > # echo '8 3774578664 linear /dev/mapper/backing-device 0' | dmsetup
> > create dmb
> > device-mapper: reload ioctl on dmb failed: Invalid argument
> > Command failed.
> >
> > I'm not sure about how it works. Is it not 8 sectors for 4k bytes?
> >
>
> It works on my side, my kernel is Linux v5.5-rc2, lvm2 version is
> 2.02.180, dmsetup version is 1.02.149. The difference is the device
> size, my disk size is much less.
>
> --
>
> Coly Li
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: undo make-bcache (was: Re: Can't mount an encrypted backing device)
2020-01-16 23:00 ` Eric Wheeler
@ 2020-01-18 11:44 ` Clodoaldo Neto
0 siblings, 0 replies; 15+ messages in thread
From: Clodoaldo Neto @ 2020-01-18 11:44 UTC (permalink / raw)
To: Eric Wheeler; +Cc: linux-bcache
On Thu, Jan 16, 2020 at 8:01 PM Eric Wheeler <bcache@lists.ewheeler.net> wrote:
>
> On Thu, 16 Jan 2020, Clodoaldo Neto wrote:
>
> > Em seg, 13 de jan de 2020 11:19, Coly Li <colyli@suse.de> escreveu:
> > >
> > > On 2020/1/13 8:44 下午, Jens-U. Mozdzen wrote:
> > > > Hi Coly,
> > > >
> > > > jumping in here, because I was looking for a way to revert from bcache
> > > > to plain device:
> > > >
> > > > Zitat von Coly Li <colyli@suse.de>:
> > > >> The super block location of the backing disk is occupied by bcache. You
> > > >> cannot mount the file system directly from the backing disk which is
> > > >> formated as bcache backing device [...] (bcache offset all I/Os on
> > > >> bcache device 4KB behind the requesting
> > > >> LBA on backing disk).
> > > >
> > > > Assuming that no caching device is associated with a backing device (so
> > > > the backing device is "clean" as in "containing all data blocks with the
> > > > current content"), could one convert the content of a backing device to
> > > > a "non-bcached device" by removing the first 4096 octets of the backing
> > > > device content?
> > > >
> > > > Something like "dd if=backingdev of=newdev skip_bytes=4096 ..."?
> > >
> > > Hi Jens-U,
> > >
> > > you may try dmsetup to setup a linear device mapper target, and the map
> > > table just skipping the first 4KB (bcache superblock area). If you are
> > > lucky, I mean the real file system is not corrupted, the created device
> > > mapper target can be mounted directly.
> >
> >
> > I'm trying dmsetup but it does not accept anything other than 0 and 0
> > at the beginning and end of the table:
> >
> > # echo '0 3774578672 linear /dev/mapper/backing-device 8' | dmsetup create dmb
> > device-mapper: reload ioctl on dmb failed: Invalid argument
> > Command failed.
> >
> > # echo '8 3774578664 linear /dev/mapper/backing-device 0' | dmsetup create dmb
> > device-mapper: reload ioctl on dmb failed: Invalid argument
> > Command failed.
> >
> > I'm not sure about how it works. Is it not 8 sectors for 4k bytes?
>
> Does dmesg give a hint?
>
# echo '0 3774578672 linear /dev/mapper/backing-device 8' | dmsetup create dmb
device-mapper: reload ioctl on dmb failed: Invalid argument
Command failed.
# dmesg | grep -E "bcache|device-mapper"
[ 0.854520] device-mapper: uevent: version 1.0.3
[ 0.854586] device-mapper: ioctl: 4.41.0-ioctl (2019-09-16)
initialised: dm-devel@redhat.com
[ 52.719925] bcache: bch_journal_replay() journal replay done, 0
keys in 1 entries, seq 1
[ 52.722965] bcache: register_cache() registered cache device sdb1
[ 52.934796] bcache: register_bdev() registered backing device md127
[ 55.628944] bcache: bch_journal_replay() journal replay done, 0
keys in 1 entries, seq 31
[ 55.629200] bcache: register_cache() registered cache device dm-2
[ 851.024624] device-mapper: table: 253:3: linear: Gap in table
[ 851.024626] device-mapper: ioctl: error adding target to table
>
> --
> Eric Wheeler
>
>
>
> >
> >
> > Clodoaldo
> >
> > >
> > > --
> > >
> > > Coly Li
> > >
> >
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: undo make-bcache (was: Re: Can't mount an encrypted backing device)
2020-01-18 10:54 ` Clodoaldo Neto
@ 2020-01-18 12:22 ` Clodoaldo Neto
2020-01-18 12:34 ` Coly Li
0 siblings, 1 reply; 15+ messages in thread
From: Clodoaldo Neto @ 2020-01-18 12:22 UTC (permalink / raw)
To: Coly Li; +Cc: Jens-U. Mozdzen, linux-bcache
On Sat, Jan 18, 2020 at 7:54 AM Clodoaldo Neto
<clodoaldo.pinto.neto@gmail.com> wrote:
>
> On Thu, Jan 16, 2020 at 9:59 PM Coly Li <colyli@suse.de> wrote:
> >
> > On 2020/1/17 5:52 上午, Clodoaldo Neto wrote:
> > >
> > > Em seg, 13 de jan de 2020 11:19, Coly Li <colyli@suse.de
> > > <mailto:colyli@suse.de>> escreveu:
> > >>
> > >> On 2020/1/13 8:44 下午, Jens-U. Mozdzen wrote:
> > >> > Hi Coly,
> > >> >
> > >> > jumping in here, because I was looking for a way to revert from bcache
> > >> > to plain device:
> > >> >
> > >> > Zitat von Coly Li <colyli@suse.de <mailto:colyli@suse.de>>:
> > >> >> The super block location of the backing disk is occupied by bcache. You
> > >> >> cannot mount the file system directly from the backing disk which is
> > >> >> formated as bcache backing device [...] (bcache offset all I/Os on
> > >> >> bcache device 4KB behind the requesting
> > >> >> LBA on backing disk).
> > >> >
> > >> > Assuming that no caching device is associated with a backing device (so
> > >> > the backing device is "clean" as in "containing all data blocks with the
> > >> > current content"), could one convert the content of a backing device to
> > >> > a "non-bcached device" by removing the first 4096 octets of the backing
> > >> > device content?
> > >> >
> > >> > Something like "dd if=backingdev of=newdev skip_bytes=4096 ..."?
> > >>
> > >> Hi Jens-U,
> > >>
> > >> you may try dmsetup to setup a linear device mapper target, and the map
> > >> table just skipping the first 4KB (bcache superblock area). If you are
> > >> lucky, I mean the real file system is not corrupted, the created device
> > >> mapper target can be mounted directly.
> > >
> > >
> > > I'm trying dmsetup but it does not accept anything other than 0 and 0
> > > at the beginning and end of the table:
> > >
> > > # echo '0 3774578672 linear /dev/mapper/backing-device 8' | dmsetup
> > > create dmb
> > > device-mapper: reload ioctl on dmb failed: Invalid argument
> > > Command failed.
> >
> > The above line should work, if 3774578672 is a correct size number in
> > sectors.
>
> I took it from the original map:
>
> # dmsetup table /dev/mapper/backing-device
> 0 3774578672 crypt aes-xts-plain64
> :64:logon:cryptsetup:7e2c0b40-8dec-4b13-8d00-b53b55160775-d0 0 251:0
> 32768
It works like this:
# echo '0 3774578664 linear /dev/mapper/backing-device 8' | dmsetup create dmb
But then I can't mount it:
# mount /dev/mapper/dmb /r
mount: /r: wrong fs type, bad option, bad superblock on
/dev/mapper/dmb, missing codepage or helper program, or other error.
>
> >
> > >
> > > # echo '8 3774578664 linear /dev/mapper/backing-device 0' | dmsetup
> > > create dmb
> > > device-mapper: reload ioctl on dmb failed: Invalid argument
> > > Command failed.
> > >
> > > I'm not sure about how it works. Is it not 8 sectors for 4k bytes?
> > >
> >
> > It works on my side, my kernel is Linux v5.5-rc2, lvm2 version is
> > 2.02.180, dmsetup version is 1.02.149. The difference is the device
> > size, my disk size is much less.
> >
> > --
> >
> > Coly Li
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: undo make-bcache (was: Re: Can't mount an encrypted backing device)
2020-01-18 12:22 ` Clodoaldo Neto
@ 2020-01-18 12:34 ` Coly Li
2020-01-18 13:43 ` Clodoaldo Neto
0 siblings, 1 reply; 15+ messages in thread
From: Coly Li @ 2020-01-18 12:34 UTC (permalink / raw)
To: clodoaldo.pinto.neto; +Cc: Jens-U. Mozdzen, linux-bcache
On 2020/1/18 8:22 下午, Clodoaldo Neto wrote:
> On Sat, Jan 18, 2020 at 7:54 AM Clodoaldo Neto
> <clodoaldo.pinto.neto@gmail.com> wrote:
>>
>> On Thu, Jan 16, 2020 at 9:59 PM Coly Li <colyli@suse.de> wrote:
>>>
>>> On 2020/1/17 5:52 上午, Clodoaldo Neto wrote:
>>>>
>>>> Em seg, 13 de jan de 2020 11:19, Coly Li <colyli@suse.de
>>>> <mailto:colyli@suse.de>> escreveu:
>>>>>
>>>>> On 2020/1/13 8:44 下午, Jens-U. Mozdzen wrote:
>>>>>> Hi Coly,
>>>>>>
>>>>>> jumping in here, because I was looking for a way to revert from bcache
>>>>>> to plain device:
>>>>>>
>>>>>> Zitat von Coly Li <colyli@suse.de <mailto:colyli@suse.de>>:
>>>>>>> The super block location of the backing disk is occupied by bcache. You
>>>>>>> cannot mount the file system directly from the backing disk which is
>>>>>>> formated as bcache backing device [...] (bcache offset all I/Os on
>>>>>>> bcache device 4KB behind the requesting
>>>>>>> LBA on backing disk).
>>>>>>
>>>>>> Assuming that no caching device is associated with a backing device (so
>>>>>> the backing device is "clean" as in "containing all data blocks with the
>>>>>> current content"), could one convert the content of a backing device to
>>>>>> a "non-bcached device" by removing the first 4096 octets of the backing
>>>>>> device content?
>>>>>>
>>>>>> Something like "dd if=backingdev of=newdev skip_bytes=4096 ..."?
>>>>>
>>>>> Hi Jens-U,
>>>>>
>>>>> you may try dmsetup to setup a linear device mapper target, and the map
>>>>> table just skipping the first 4KB (bcache superblock area). If you are
>>>>> lucky, I mean the real file system is not corrupted, the created device
>>>>> mapper target can be mounted directly.
>>>>
>>>>
>>>> I'm trying dmsetup but it does not accept anything other than 0 and 0
>>>> at the beginning and end of the table:
>>>>
>>>> # echo '0 3774578672 linear /dev/mapper/backing-device 8' | dmsetup
>>>> create dmb
>>>> device-mapper: reload ioctl on dmb failed: Invalid argument
>>>> Command failed.
>>>
>>> The above line should work, if 3774578672 is a correct size number in
>>> sectors.
>>
>> I took it from the original map:
>>
>> # dmsetup table /dev/mapper/backing-device
>> 0 3774578672 crypt aes-xts-plain64
>> :64:logon:cryptsetup:7e2c0b40-8dec-4b13-8d00-b53b55160775-d0 0 251:0
>> 32768
>
> It works like this:
>
> # echo '0 3774578664 linear /dev/mapper/backing-device 8' | dmsetup create dmb
>
> But then I can't mount it:
>
> # mount /dev/mapper/dmb /r
> mount: /r: wrong fs type, bad option, bad superblock on
> /dev/mapper/dmb, missing codepage or helper program, or other error.
It might be my fault, from bcache-tools, it seems the offset is
BDEV_DATA_START_DEFAULT (16 sectors). How about:
# echo '0 3774578656 linear /dev/mapper/backing-device 16' | dmsetup
create dmb
--
Coly Li
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: undo make-bcache (was: Re: Can't mount an encrypted backing device)
2020-01-18 12:34 ` Coly Li
@ 2020-01-18 13:43 ` Clodoaldo Neto
2020-01-18 14:16 ` Coly Li
0 siblings, 1 reply; 15+ messages in thread
From: Clodoaldo Neto @ 2020-01-18 13:43 UTC (permalink / raw)
To: Coly Li; +Cc: Jens-U. Mozdzen, linux-bcache
On Sat, Jan 18, 2020 at 9:35 AM Coly Li <colyli@suse.de> wrote:
>
> On 2020/1/18 8:22 下午, Clodoaldo Neto wrote:
> > On Sat, Jan 18, 2020 at 7:54 AM Clodoaldo Neto
> > <clodoaldo.pinto.neto@gmail.com> wrote:
> >>
> >> On Thu, Jan 16, 2020 at 9:59 PM Coly Li <colyli@suse.de> wrote:
> >>>
> >>> On 2020/1/17 5:52 上午, Clodoaldo Neto wrote:
> >>>>
> >>>> Em seg, 13 de jan de 2020 11:19, Coly Li <colyli@suse.de
> >>>> <mailto:colyli@suse.de>> escreveu:
> >>>>>
> >>>>> On 2020/1/13 8:44 下午, Jens-U. Mozdzen wrote:
> >>>>>> Hi Coly,
> >>>>>>
> >>>>>> jumping in here, because I was looking for a way to revert from bcache
> >>>>>> to plain device:
> >>>>>>
> >>>>>> Zitat von Coly Li <colyli@suse.de <mailto:colyli@suse.de>>:
> >>>>>>> The super block location of the backing disk is occupied by bcache. You
> >>>>>>> cannot mount the file system directly from the backing disk which is
> >>>>>>> formated as bcache backing device [...] (bcache offset all I/Os on
> >>>>>>> bcache device 4KB behind the requesting
> >>>>>>> LBA on backing disk).
> >>>>>>
> >>>>>> Assuming that no caching device is associated with a backing device (so
> >>>>>> the backing device is "clean" as in "containing all data blocks with the
> >>>>>> current content"), could one convert the content of a backing device to
> >>>>>> a "non-bcached device" by removing the first 4096 octets of the backing
> >>>>>> device content?
> >>>>>>
> >>>>>> Something like "dd if=backingdev of=newdev skip_bytes=4096 ..."?
> >>>>>
> >>>>> Hi Jens-U,
> >>>>>
> >>>>> you may try dmsetup to setup a linear device mapper target, and the map
> >>>>> table just skipping the first 4KB (bcache superblock area). If you are
> >>>>> lucky, I mean the real file system is not corrupted, the created device
> >>>>> mapper target can be mounted directly.
> >>>>
> >>>>
> >>>> I'm trying dmsetup but it does not accept anything other than 0 and 0
> >>>> at the beginning and end of the table:
> >>>>
> >>>> # echo '0 3774578672 linear /dev/mapper/backing-device 8' | dmsetup
> >>>> create dmb
> >>>> device-mapper: reload ioctl on dmb failed: Invalid argument
> >>>> Command failed.
> >>>
> >>> The above line should work, if 3774578672 is a correct size number in
> >>> sectors.
> >>
> >> I took it from the original map:
> >>
> >> # dmsetup table /dev/mapper/backing-device
> >> 0 3774578672 crypt aes-xts-plain64
> >> :64:logon:cryptsetup:7e2c0b40-8dec-4b13-8d00-b53b55160775-d0 0 251:0
> >> 32768
> >
> > It works like this:
> >
> > # echo '0 3774578664 linear /dev/mapper/backing-device 8' | dmsetup create dmb
> >
> > But then I can't mount it:
> >
> > # mount /dev/mapper/dmb /r
> > mount: /r: wrong fs type, bad option, bad superblock on
> > /dev/mapper/dmb, missing codepage or helper program, or other error.
>
> It might be my fault, from bcache-tools, it seems the offset is
> BDEV_DATA_START_DEFAULT (16 sectors). How about:
> # echo '0 3774578656 linear /dev/mapper/backing-device 16' | dmsetup
> create dmb
Still no luck
# echo '0 3774578656 linear /dev/mapper/backing-device 16' | dmsetup create dmb
# mount /dev/mapper/dmb /r
mount: /r: wrong fs type, bad option, bad superblock on
/dev/mapper/dmb, missing codepage or helper program, or other error.
Clodoaldo
>
>
> --
>
> Coly Li
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: undo make-bcache (was: Re: Can't mount an encrypted backing device)
2020-01-18 13:43 ` Clodoaldo Neto
@ 2020-01-18 14:16 ` Coly Li
2020-01-18 14:31 ` Coly Li
0 siblings, 1 reply; 15+ messages in thread
From: Coly Li @ 2020-01-18 14:16 UTC (permalink / raw)
To: clodoaldo.pinto.neto; +Cc: Jens-U. Mozdzen, linux-bcache
On 2020/1/18 9:43 下午, Clodoaldo Neto wrote:
> On Sat, Jan 18, 2020 at 9:35 AM Coly Li <colyli@suse.de> wrote:
>>
>> On 2020/1/18 8:22 下午, Clodoaldo Neto wrote:
>>> On Sat, Jan 18, 2020 at 7:54 AM Clodoaldo Neto
>>> <clodoaldo.pinto.neto@gmail.com> wrote:
>>>>
>>>> On Thu, Jan 16, 2020 at 9:59 PM Coly Li <colyli@suse.de> wrote:
>>>>>
>>>>> On 2020/1/17 5:52 上午, Clodoaldo Neto wrote:
>>>>>>
>>>>>> Em seg, 13 de jan de 2020 11:19, Coly Li <colyli@suse.de
>>>>>> <mailto:colyli@suse.de>> escreveu:
>>>>>>>
>>>>>>> On 2020/1/13 8:44 下午, Jens-U. Mozdzen wrote:
>>>>>>>> Hi Coly,
>>>>>>>>
>>>>>>>> jumping in here, because I was looking for a way to revert from bcache
>>>>>>>> to plain device:
>>>>>>>>
>>>>>>>> Zitat von Coly Li <colyli@suse.de <mailto:colyli@suse.de>>:
>>>>>>>>> The super block location of the backing disk is occupied by bcache. You
>>>>>>>>> cannot mount the file system directly from the backing disk which is
>>>>>>>>> formated as bcache backing device [...] (bcache offset all I/Os on
>>>>>>>>> bcache device 4KB behind the requesting
>>>>>>>>> LBA on backing disk).
>>>>>>>>
>>>>>>>> Assuming that no caching device is associated with a backing device (so
>>>>>>>> the backing device is "clean" as in "containing all data blocks with the
>>>>>>>> current content"), could one convert the content of a backing device to
>>>>>>>> a "non-bcached device" by removing the first 4096 octets of the backing
>>>>>>>> device content?
>>>>>>>>
>>>>>>>> Something like "dd if=backingdev of=newdev skip_bytes=4096 ..."?
>>>>>>>
>>>>>>> Hi Jens-U,
>>>>>>>
>>>>>>> you may try dmsetup to setup a linear device mapper target, and the map
>>>>>>> table just skipping the first 4KB (bcache superblock area). If you are
>>>>>>> lucky, I mean the real file system is not corrupted, the created device
>>>>>>> mapper target can be mounted directly.
>>>>>>
>>>>>>
>>>>>> I'm trying dmsetup but it does not accept anything other than 0 and 0
>>>>>> at the beginning and end of the table:
>>>>>>
>>>>>> # echo '0 3774578672 linear /dev/mapper/backing-device 8' | dmsetup
>>>>>> create dmb
>>>>>> device-mapper: reload ioctl on dmb failed: Invalid argument
>>>>>> Command failed.
>>>>>
>>>>> The above line should work, if 3774578672 is a correct size number in
>>>>> sectors.
>>>>
>>>> I took it from the original map:
>>>>
>>>> # dmsetup table /dev/mapper/backing-device
>>>> 0 3774578672 crypt aes-xts-plain64
>>>> :64:logon:cryptsetup:7e2c0b40-8dec-4b13-8d00-b53b55160775-d0 0 251:0
>>>> 32768
>>>
>>> It works like this:
>>>
>>> # echo '0 3774578664 linear /dev/mapper/backing-device 8' | dmsetup create dmb
>>>
>>> But then I can't mount it:
>>>
>>> # mount /dev/mapper/dmb /r
>>> mount: /r: wrong fs type, bad option, bad superblock on
>>> /dev/mapper/dmb, missing codepage or helper program, or other error.
>>
>> It might be my fault, from bcache-tools, it seems the offset is
>> BDEV_DATA_START_DEFAULT (16 sectors). How about:
>> # echo '0 3774578656 linear /dev/mapper/backing-device 16' | dmsetup
>> create dmb
>
> Still no luck
>
> # echo '0 3774578656 linear /dev/mapper/backing-device 16' | dmsetup create dmb
> # mount /dev/mapper/dmb /r
> mount: /r: wrong fs type, bad option, bad superblock on
> /dev/mapper/dmb, missing codepage or helper program, or other error.
The tricky part is to calculate the correct linear mapping size.
For example, I have a 500G hard drive, from fdisk I see its size is
1048576000 sectors. I use it as a bcache backing device and format an
Ext4 file system on it. Then I use the following mistaken command line
to setup a linear target to skip the first 8 sectors,
# echo '0 1048575000 linear /dev/sdc 16' | dmsetup create dmb
Then mount /dev/mapper/dmb to /mnt fails, the kmesg hints me,
[1884572.477316] EXT4-fs (dm-0): bad geometry: block count 131071998
exceeds size of device (131071875 blocks)
So I realize Ext4 file system will check the block device size, so I
need to provide an exact accurate length number for the linear target.
From the kmesg I see the correct sector size should be
(131071998*8=)1048575984, then I re-create the linear target by,
# echo '0 1048575984 linear /dev/sdc 16' | dmsetup create dmb
Then I mount /dev/mapper/dmb to /mnt, it works and I have the following
line from command 'mount',
/dev/mapper/dmb on /mnt type ext4 (rw,relatime)
I don't use the encrpyt file system and I don't know the excact detail
about it. But I guess, it might because the incorrect length number for
your dm linear target as I show by the above example.
--
Coly Li
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: undo make-bcache (was: Re: Can't mount an encrypted backing device)
2020-01-18 14:16 ` Coly Li
@ 2020-01-18 14:31 ` Coly Li
0 siblings, 0 replies; 15+ messages in thread
From: Coly Li @ 2020-01-18 14:31 UTC (permalink / raw)
To: clodoaldo.pinto.neto; +Cc: Jens-U. Mozdzen, linux-bcache
On 2020/1/18 10:16 下午, Coly Li wrote:
>>>> It works like this:
>>>>
>>>> # echo '0 3774578664 linear /dev/mapper/backing-device 8' | dmsetup create dmb
>>>>
>>>> But then I can't mount it:
>>>>
>>>> # mount /dev/mapper/dmb /r
>>>> mount: /r: wrong fs type, bad option, bad superblock on
>>>> /dev/mapper/dmb, missing codepage or helper program, or other error.
>>>
>>> It might be my fault, from bcache-tools, it seems the offset is
>>> BDEV_DATA_START_DEFAULT (16 sectors). How about:
>>> # echo '0 3774578656 linear /dev/mapper/backing-device 16' | dmsetup
>>> create dmb
>>
>> Still no luck
>>
>> # echo '0 3774578656 linear /dev/mapper/backing-device 16' | dmsetup create dmb
>> # mount /dev/mapper/dmb /r
>> mount: /r: wrong fs type, bad option, bad superblock on
>> /dev/mapper/dmb, missing codepage or helper program, or other error.
>
> The tricky part is to calculate the correct linear mapping size.
>
> For example, I have a 500G hard drive, from fdisk I see its size is
> 1048576000 sectors. I use it as a bcache backing device and format an
> Ext4 file system on it. Then I use the following mistaken command line
> to setup a linear target to skip the first 8 sectors,
> # echo '0 1048575000 linear /dev/sdc 16' | dmsetup create dmb
> Then mount /dev/mapper/dmb to /mnt fails, the kmesg hints me,
> [1884572.477316] EXT4-fs (dm-0): bad geometry: block count 131071998
> exceeds size of device (131071875 blocks)
>
> So I realize Ext4 file system will check the block device size, so I
> need to provide an exact accurate length number for the linear target.
> From the kmesg I see the correct sector size should be
> (131071998*8=)1048575984, then I re-create the linear target by,
> # echo '0 1048575984 linear /dev/sdc 16' | dmsetup create dmb
> Then I mount /dev/mapper/dmb to /mnt, it works and I have the following
> line from command 'mount',
> /dev/mapper/dmb on /mnt type ext4 (rw,relatime)
>
> I don't use the encrpyt file system and I don't know the excact detail
> about it. But I guess, it might because the incorrect length number for
> your dm linear target as I show by the above example.
>
Sorry I realize maybe I mislead you....
I re-read the first email, it seems you create the bcache backing device
on top of a raid raid1, then you cryptsetup on the bcache device.
So I guess the linear dm target should be created on top of the md
raid1, not /dev/mapper/backing-device. Which might be,
# echo '0 3774578656 linear /dev/md127 16' | dmsetup create dmb
The above line assumes luks has its superblock on offset zero from its
own LBA, and <0 3774578656> should be a correct pair.
If all the offset numbers are correct, dmb should be the block device
for your to run cryptsetup open. Then you will have a
/dev/mapper/backing-device for following mount.
--
Coly Li
^ permalink raw reply [flat|nested] 15+ messages in thread
end of thread, other threads:[~2020-01-18 14:31 UTC | newest]
Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
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2020-01-11 13:42 ` Can't mount an encrypted backing device Clodoaldo Neto
2020-01-16 22:55 ` Eric Wheeler
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2020-01-13 12:44 ` undo make-bcache (was: Re: Can't mount an encrypted backing device) Jens-U. Mozdzen
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2020-01-16 21:56 ` Clodoaldo Neto
2020-01-16 23:00 ` Eric Wheeler
2020-01-18 11:44 ` Clodoaldo Neto
2020-01-17 0:58 ` Coly Li
2020-01-18 10:54 ` Clodoaldo Neto
2020-01-18 12:22 ` Clodoaldo Neto
2020-01-18 12:34 ` Coly Li
2020-01-18 13:43 ` Clodoaldo Neto
2020-01-18 14:16 ` Coly Li
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