Date: Sat, 31 May 2014 11:49:10 -0600 From: Warner Losh <imp@bsdimp.com> To: Adrian Chadd <adrian@freebsd.org> Cc: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org>, Bernd Walter <ticso@cicely7.cicely.de>, ticso@cicely.de, Ian Lepore <ian@freebsd.org> Subject: Re: TRIM on SD cards Message-ID: <C6388C10-C534-4141-B44C-1EEB29493A05@bsdimp.com> In-Reply-To: <CAJ-Vmom=r9FA_HWLTjgThSZPncGw3dkCknNGCEpd=F39AJN8ww@mail.gmail.com> References: <20140531004306.GI26883@cicely7.cicely.de> <1401505209.20883.34.camel@revolution.hippie.lan> <20140531102305.GK26883@cicely7.cicely.de> <05005B04-1BDA-4242-946B-28D0DA069A42@bsdimp.com> <CAJ-Vmom=r9FA_HWLTjgThSZPncGw3dkCknNGCEpd=F39AJN8ww@mail.gmail.com>
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[-- Attachment #1 --] On May 31, 2014, at 11:31 AM, Adrian Chadd <adrian@freebsd.org> wrote: > On 31 May 2014 09:45, Warner Losh <imp@bsdimp.com> wrote: > >> One of the things that I did for images years ago was compressed tar files. There was so much variation between CF makers and at the time CF geometry was important to the BIOS, so we made our images as tar balls. We then had a makefile target that would create a partition on the card that was actually there, put boot blocks on it then extract the tarball… I never have liked DD for creating images, even when LBAs ruled the day because you’d always have to grow/shrink the FS afterwards. The only advantage it had was it was easy… Perhaps it is time to go back to that model? The alternative that wouldn’t suck too bad would be to create variable sized images based on how much data was actually present and ensure there are no holes (or minimal holes) in the filesystem. >> >> Hmmm, if we know WHAT filesystem we’re dealing with, then we could perhaps enhance fsck and/or growfs to BIO_DELETE all the blocks that it knows are free, which would be a useful, data-driven approach that could ensure we start out with a nicely trimmed FS. Given the vagaries of the different kinds of TRIMs and the various translation layers we have, that might be the most robust. > > Having makefs spit this out would be rather useful. I’m not sure it would be. Any writes to the FS after you create it would invalidate the list… Far easier to have fsck do it for you any time you need it... Warner [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJTihYWAAoJEGwc0Sh9sBEAsNEP/iiQ2M4RJVnHVZFWrJtqSbWo 6n+NWhW35joaG3MVOgwCdburr/OwIfn/X3KPsapMTnzfzAjhlp93BXM/4/FrtVDs /Et5ksG93BbreFcru5HRlqP2OF4h4m3lHCjTq8d1mTNIMdNeRotsfGyVmGuxK6Ap 5gDquaRi9/Y5djh8f+6z3Ca/QLSB4qXprML/jWFdh0skgcT9eIQftKmjYprgol5n 6f9HQHbj1mAUOcthw4JNbb4h5Bl8kknV2kf5Flb49RekuSce3WRPdPbNqWRwq6Nr wLQiBeKk+u7lN7dRZMVlPNXaJAd6r+UBmCHOhbxx4KNIW2TUowGg14eJ6toknmGX ein0/7snDWx/Ee1d9OGGMwRRLq0dlO1fcONywx+P9Q5TODH2/FtVlewI8yeEXfZQ VwxeOoh7vS49sZOxukqpmEdsDe5eWKmPT5Ot+T88EGgVhKXpMNLSLlPTsqbZBEQN P3Axw1UPnlI1DyQHz2Nkg8omGEnEAc2GRmc+9u9PbMkVq+PUFCuohMxtGh302KWd Ajkz8x3s2IZAcs5njyAJjVrSJrsL5B3GREitwHGPgHNRdsZfV0LOTg08Y/XhToGq cRrSbgE+2lZ7qiYXIaAcWas2qFfxTOUWdmHEixrZAetZ+Gn5TAtRCKhmSHY6Raqs tz8B3jy3QRKWlyLB13rT =jDja -----END PGP SIGNATURE-----home | help
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