[dm-devel] [PATCH][RFC] dm: Do not open log and cow device read-write for read-only mappings
Alasdair G Kergon
agk at redhat.com
Tue Feb 15 15:46:25 UTC 2011
On Tue, Feb 15, 2011 at 04:20:33PM +0100, Tejun Heo wrote:
> Hmmm... but -EACCES is the correct one here. The device node itself
> is rejecting RW access. There's no FS which is enforcing RO.
Exactly:) If the filesystem permissions were what was blocking this
(say r--) then I'd agree with EACCES. Interpret those man pages in the
context of 'pathname refers to a block device not a file'.
If it's EACCES, I just need to gain more privilege/capabilities and then
repeat the system call and it could succeed.
But EROFS tells me however much extra privilege I get it's going to make
no difference.
That's why I'm arguing EACCES is not a good error to return and EROFS is
more appropriate.
Alasdair
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