From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yann E. MORIN Date: Wed, 22 Aug 2018 19:21:34 +0200 Subject: [Buildroot] [PATCH 2/2] Adding btrfs rootfs option. In-Reply-To: <20180822165751.GB2404@scaer> References: <20180821160412.28757-1-robert.heywood@codethink.co.uk> <20180821160412.28757-2-robert.heywood@codethink.co.uk> <20180821202707.GP15347@scaer> <20180822165751.GB2404@scaer> Message-ID: <20180822172134.GC2404@scaer> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Robert, All, On 2018-08-22 18:57 +0200, Yann E. MORIN spake thusly: > On 2018-08-22 14:10 +0100, Robert Heywood spake thusly: > > On 21/08/18 21:27, Yann E. MORIN wrote: [--SNIP--] > > >Given that the filsystem is specifically made for the target that will > > >mount it, does it make sense to ffer that option at all? I.e. if the > > >target uses a 4KiB page size, does it make sense to generatea rootfs > > >that has a different secotr size, and thus not mountable on the target > > >at all? > > > > > >My suggestion: don't add that option. > > > > On my system (building for a raspi0) it autodetects the sector size to be > > 4k, and the resulting image is bootable. However I'm worried the host won't > > be able to detect the correct value for the target. In such a case I can see > > why it would be useful to set the sector size explicitly. > > Well, basically all architectures have a 4K page size, so does your > x86_64 and so does the rpi (0/1/2/3), so the default for your host is > valid for your target. > > What architectures have a page-size that is not 4K? After discussing on IRC with Paul (Cc), it turns out that quite a few architectures can have a page size different from 4K, like mips, arc and a few others. Sometimes it is even configrable. Thanks Paul. 4K just happens to be the most common, but definitely not the only one. > > Is there another place where the sector size is specified? If so, it might > > be better to use the existing value instead. > I would also add a default here, to 4096. Users who want to change > that value would know what they would be doing. So yeah, just keep that option, and let set the default to 4K. People who have a non 4K arch or kernel option will know to change that value. Regards, Yann E. MORIN. -- .-----------------.--------------------.------------------.--------------------. | Yann E. MORIN | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: | | +33 662 376 056 | Software Designer | \ / CAMPAIGN | ___ | | +33 223 225 172 `------------.-------: X AGAINST | \e/ There is no | | http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL | v conspiracy. | '------------------------------^-------^------------------^--------------------'