Re: [PATCH-FOR-38] target: Fix READ_CAPACITY_16 regression

["Nicholas A. Bellinger" <nab@linux-iscsi.org>]

On Fri, 2011-03-11 at 17:17 -0600, James Bottomley wrote:
> On Wed, 2011-03-02 at 15:52 -0800, Nicholas A. Bellinger wrote:
> > From: Nicholas Bellinger <nab@linux-iscsi.org>
> > 
> > Hi James,
> > 
> > This patch fixes a regression for READ_CAPACITY to trigger SAI READ_CAPACITY_16 for
> > >= 0xffffffff virtual backends.  This occured during v4.0.0-rc6 when the backend
> > read_capacity* handlers where moved into generic target_core_cdb.c code, and the
> > 'unsigned long long blocks_long' piece was dropped from target_emulate_readcapacity().
> > 
> > This fix has been tested with TCM_Loop on .38-rc7 with lio-4.1 and is working as expected
> > with large block virtual backends:
> > 
> > [67826.897061] TARGET_CORE[loopback]->TPG[1]_LUN[0] - Adding READ-WRITE access for LUN in Demo Mode
> > [67826.897061] scsi 7:0:1:0: Direct-Access     LIO-ORG  FILEIO           4.0  PQ: 0 ANSI: 5
> > [67826.900933] sd 7:0:1:0: [sdd] 2621440000001 512-byte logical blocks: (1.34 PB/1.19 PiB)
> > [67826.901510] sd 7:0:1:0: [sdd] Write Protect is off
> > [67826.901684] sd 7:0:1:0: [sdd] Mode Sense: 2f 00 00 00
> > 
> > Please include into scsi-rc-fixes going to Linus for-38 mainline target code.
> 
> So the piece you didn't say is that this only affects volumes >2TB
> volume which misreport the capacity (which is actually what the bug
> description should have been).
> 
> That's hardly an oopsworthy fix at this stage ... I'll put it into misc
> with a cc stable.
> 

This has already been picked up by AKPM last week, and (I assume) will
be queued to Linus for .38-FINAL via -mm.

Considering that is a critical fix that is not trigger by some obsecure
corner case, I am not sure why this would be deferred for for a
v2.6.38.x release when we already have a proper fix in place..?

--nab