Messages in this thread | | | Date | Mon, 6 Jan 2020 10:40:17 -0800 | From | Jaegeuk Kim <> | Subject | Re: [f2fs-dev] Multidevice f2fs mount after disk rearrangement |
| |
On 01/06, Chao Yu wrote: > Hello, > > Thanks for the report. :) > > On 2020/1/5 5:52, Oleksandr Natalenko via Linux-f2fs-devel wrote: > > Hi. > > > > On 04.01.2020 17:29, Oleksandr Natalenko wrote: > >> I was brave enough to create f2fs filesystem spanning through 2 > >> physical device using this command: > >> > >> # mkfs.f2fs -t 0 /dev/sdc -c /dev/sdd > >> > >> It worked fine until I removed /dev/sdb from my system, so f2fs devices > >> became: > >> > >> /dev/sdc -> /dev/sdb > >> /dev/sdd -> /dev/sdc > >> > >> Now, when I try to mount it, I get the following: > >> > >> # mount -t f2fs /dev/sdb /mnt/fs > >> mount: /mnt/fs: mount(2) system call failed: No such file or directory. > >> > >> In dmesg: > >> > >> [Jan 4 17:25] F2FS-fs (sdb): Mount Device [ 0]: /dev/sdc, > >> 59063, 0 - 1cd6fff > >> [ +0,000024] F2FS-fs (sdb): Failed to find devices > >> > >> fsck also fails with the following assertion: > >> > >> [ASSERT] (init_sb_info: 908) !strcmp((char *)sb->devs[i].path, (char > >> *)c.devices[i].path) > >> > >> Am I doing something obviously stupid, and the device path can be > >> (somehow) changed so that the mount succeeds, or this is unfixable, > >> and f2fs relies on persistent device naming? > >> > >> Please suggest. > >> > >> Thank you. > > > > Erm, fine. I studied f2fs-tools code a little bit and discovered that > > superblock indeed had /dev/sdX paths saved as strings. So I fired up > > hexedit and just changed the superblock directly on the first device, > > substituting sdc with sdb and sdd with sdc (I did it twice; I guess > > there are 2 copies of superblock), and after this the mount worked. > > Alright, it works if superblock checksum feature is off... > > > > > Am I really supposed to do this manually ;)? > > We'd better add that ability in tune.f2fs. And I guess we need to let > kernel/fsck to notice that case, and give hint to run tune.f2fs to > reconfigure primary/secondary/... device paths.
I'm thinking to add tunesb.f2fs to edit superblock explicitly, since it has to edit it without getting superblock/checkpoint and other f2fs metadata.
For example, # tunesb.f2fs -c /dev/sdb -c /dev/sdc /dev/sda .. superblock info .. .. device list .. .. hot/cold extensions ..
Will modify the device list, if it's different from parameter.
> > Thanks, > > >
| |