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Groups > linux.kernel > #1450524
| From | Kent Overstreet <kent.overstreet@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: bcache super block corruption with non 4k pages |
| Date | 2016-07-26 12:30 +0200 |
| Message-ID | <rZ7MC-L7-17@gated-at.bofh.it> (permalink) |
| References | <rZ7jz-lC-9@gated-at.bofh.it> <rZ7jz-lC-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, Jul 26, 2016 at 11:51:25AM +0200, Stefan Bader wrote: > On 21.07.2016 10:58, Stefan Bader wrote: > > I was pointed at the thread which seems to address the same after > > I wrote most of below text. Did not want to re-write this so please > > bear with the odd layout. > > > > https://www.redhat.com/archives/dm-devel/2016-June/msg00015.html > > > > Zhengyuan tries to fix the problem by relocating the superblock on > > disk. But I am not sure whether there is really any guarantee about > > how __bread fills data into the buffer_head. What if there is the next > > odd arch with 128K pages? > > > > So below is an attempt to be more generic. Still I don't feel completely > > happy with the way that a page moves (or is shared) between buffer_head > > and biovec. What I tried to outline below is to let the register functions > > allocate bio+biovec memory and use the in-memory sb_cache data to initialize > > the biovec buffer. > > Any opinions here? Also adding LKML as I don't seem to get through moderation on > dm-devel. The correct solution is to rip out the __bread() and just read the superblock by issuing a bio, the same way all the other IO in bcache is done. This is the way it's done in the bcache-dev branch - unfortunately, the patch that does that in bcache-dev is big and invasive and probably not worth the hassle to backport: https://evilpiepirate.org/git/linux-bcache.git/commit/?h=bcache-dev&id=303eb67bffad57b4d9e71523e7df04bf258e66d1 Probably best to just do something small and localized.
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Re: bcache super block corruption with non 4k pages Stefan Bader <stefan.bader@canonical.com> - 2016-07-26 12:00 +0200
Re: bcache super block corruption with non 4k pages Kent Overstreet <kent.overstreet@gmail.com> - 2016-07-26 12:30 +0200
Re: bcache super block corruption with non 4k pages Stefan Bader <stefan.bader@canonical.com> - 2016-07-26 14:40 +0200
Re: bcache super block corruption with non 4k pages Kent Overstreet <kent.overstreet@gmail.com> - 2016-07-26 14:50 +0200
Re: bcache super block corruption with non 4k pages Stefan Bader <stefan.bader@canonical.com> - 2016-07-27 17:20 +0200
Re: bcache super block corruption with non 4k pages Kent Overstreet <kent.overstreet@gmail.com> - 2016-07-28 08:00 +0200
Re: bcache super block corruption with non 4k pages Stefan Bader <stefan.bader@canonical.com> - 2016-07-28 18:30 +0200
Re: bcache super block corruption with non 4k pages Stefan Bader <stefan.bader@canonical.com> - 2016-08-04 12:30 +0200
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