Re: [BusyBox] [Fwd: Loopback device setup?]

From: Tom Guilliams
Date: Tue Feb 17 2004 - 17:46:05 EST


Thanks to all who responded. I have a 2.4.20 kernel so mounting on the tmpfs is not supported. I have found an alternative by using the ram device nodes for storage.

Thanks again,

Tom

Hugh Dickins wrote:
On Tue, 17 Feb 2004, vda wrote:

On Tuesday 17 February 2004 02:20, Tom Guilliams wrote:

in /driver/block/loop.c -

loop_set_fd()

/*
* If we can't read - sorry. If we only can't write -
* well, it's going to be read-only.
*/
if (!aops->readpage)
goto out_putf;

I confirmed the "if (!aops->readpage)" is true. I'm not sure what the
readpage routine is trying to do (which dev or file) in my command below -
# mount -t ext2 -o loop ramdisk.image rootfs

Anyone have any thoughts?? This is all being done in the /tmp
dircectory which is mounted as "tmpfs". Not sure if that has anything
to do with it.

I recall that tmpfs cannot do readpage (by design?).
CCing LKML, maybe someone will pour in more info.


readpage is not straightforward for tmpfs, so it took a long time
to be added, but tmpfs has supported loop since 2.4.22 and 2.5.45.

Hugh


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