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On 2012-12-23, Michael Mol wrote: |
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> On Dec 23, 2012 12:46 PM, "Nuno J. Silva" <nunojsilva@×××××××.pt> wrote: |
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>> |
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>> On 2012-12-23, Alan Mackenzie wrote: |
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>> |
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>> > On Sun, Dec 23, 2012 at 07:03:25PM +0200, Nuno J. Silva wrote: |
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>> >> On 2012-12-23, Alan McKinnon wrote: |
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>> > |
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>> >> > On Sun, 23 Dec 2012 12:22:24 +0200 |
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>> >> > nunojsilva@×××××××.pt (Nuno J. Silva) wrote: |
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>> > |
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>> >> >> On 2012-12-18, Alan McKinnon wrote: |
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>> > |
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>> >> >> > On Tue, 18 Dec 2012 09:08:53 -0500 |
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>> >> >> > Michael Mol <mikemol@×××××.com> wrote: |
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>> > |
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>> > |
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>> >> >> > This sentence summarizes my understanding of your post nicely: |
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>> > |
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>> >> >> >> Now, why is /usr special? It's because it contains executable |
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> code |
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>> >> >> >> the system might require while launching. |
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>> > |
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>> >> >> > Now there are only two approaches that could solve that problem: |
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>> > |
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>> >> >> > 1. Avoid it entirely |
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>> >> >> > 2. Deal with it using any of a variety of bootstrap techniques |
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>> > |
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>> >> >> > #1 is handled by policy, whereby any code the system might require |
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>> >> >> > while launching is not in /usr. |
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>> > |
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>> >> >> > #2 already has a solution, it's called an init*. Other solutions |
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>> >> >> > exist but none are as elegant as a throwaway temporary filesystem |
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>> >> >> > in RAM. |
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>> > |
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>> >> >> What about just mounting /usr as soon as the system boots? |
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>> > |
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>> > |
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>> >> > Please read the thread next time. The topic under discussion is |
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>> >> > solutions to the problem of not being able to do exactly that. |
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>> > |
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>> >> Then I suppose you can surely explain in a nutshell why can't init |
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>> >> scripts simply do that? |
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>> > |
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>> > Because certain people with influence have rearranged the filesystem so |
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>> > that programs within /usr are absolutely necessary for booting; they are |
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>> > needed _before_ init has a chance to mount /usr. So either /usr has to |
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>> > be in the root partition, or crazy kludges need to be used to mount /usr |
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>> > before the kernel runs init. |
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>> |
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>> I surely don't know the udev architecture well enough, but if this is |
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>> all done by the udev daemon, can't we just "mount /usr" before the |
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>> daemon is started? The only needed things should be mount (which is |
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>> under /bin here) and /etc/fstab. |
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>> |
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>> Or is something outside udev needing stuff under /usr? |
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> |
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> Yes. That's the pivot of the problem. |
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What is it? |
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I tried and I was able to mount a filesystem other than / shortly after |
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linux has passed control to init, in fact, with no udev stuff running. |
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-- |
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Nuno Silva (aka njsg) |
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http://njsg.sdf-eu.org/ |
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