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From: Arnd Bergmann <arnd@arndb.de>
To: Stuart Swales <stuart.swales.croftnuisk@gmail.com>
Subject: Re: [PATCH] adfs: add hexadecimal filetype suffix option
Date: Fri, 21 Jan 2011 17:47:17 +0100
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On Friday 21 January 2011 15:34:12 Stuart Swales wrote:
> 
> [PATCH] adfs: add hexadecimal filetype suffix option
> 
> ADFS (FileCore) storage complies with the RISC OS filetype specification
> (12 bits of file type information is stored in the file load address, rather
> than using a file extension).  The existing driver largely ignores this
> information and does not present it to the end user.
> 
> It is desirable that stored filetypes be made visible to the end user to
> facilitate a precise copy of data and metadata from a hard disc (or image
> thereof) into a RISC OS emulator (such as RPCEmu) or to a network share which
> can be accessed by real Acorn systems.
> 
> This patch implements a per-mount filetype suffix option (use -o ftsuffix=1)
> to present any filetype as a ,xyz hexadecimal suffix on each file.  This type
> suffix is compatible with that used by RISC OS systems that access network
> servers using NFS client software and by RPCemu's host filing system.
> 
> Signed-off-by: Stuart Swales <stuart.swales.croftnuisk@gmail.com>

The patch looks fine to me, but it tells me that you have some knowledge
and interest in this file system. Adfs is currently one of only a handful
of modules in the kernel that still uses the big kernel lock, because
nobody so far had enough motivation to fix this.

Would you be able to take a look at this? The straightforward approach
would be to add a mutex to adfs_sb_info and use that in place of
lock_kernel. It's mostly a matter of testing to make sure that no
deadlocks get introduced in the process.

	Arnd