Re: async pass(4) patches available

"Kenneth D. Merry" <ken_at_FreeBSD.ORG> wrote:

> On Mon, Apr 06, 2015 at 15:39:56 +0200, Fabian Keil wrote:
> > "Kenneth D. Merry" <ken_at_FreeBSD.ORG> wrote:
> > 
> > > I have put patches to add an asynchronous interface to the pass(4)
> > > driver and add a new camdd(8) utility here:
> > > 
> > > FreeBSD/head as of SVN revision 280857:
> > > 
> > > http://people.freebsd.org/~ken/async_pass.head.20150330.1.txt
> > [...]
> > > Comments and testing are welcome!  As I said, camdd(8) in particular
> > > is a work in progress.  It could use some cleanup and there are some
> > > more useful features that could be added there.
> > 
> > I've been using the patch for a couple of days on an amd64 system
> > based on 11.0-CURRENT r280952 and didn't notice any obvious
> > regressions using the system as usual.
[...] 
> > I also tried to test camdd, but didn't get it to work.
> > Some failed attempts:
> > 
> > [fk_at_kendra ~]$ sudo camdd -i pass=da0,bs=65536 -o file=blafsel.img
> > (pass2:umass-sim0:0:0:0): READ(6). CDB: 08 00 00 00 80 00 
> > (pass2:umass-sim0:0:0:0): CAM status: CCB request completed with an
> > error 13 bytes read from pass2
> > 13 bytes written to blafsel.img
> > 20.3203 seconds elapsed
> > 0.00 MB/sec
> > [fk_at_kendra ~]$ sudo hd blafsel.img 
> > 00000000  55 53 42 53 d9 02 00 00  00 00 01 00 01
> > |USBS.........| 0000000d
> > [fk_at_kendra ~]$ sudo dd if=/dev/da0 bs=1k count=1  | hd | head -n 1
> > 1+0 records in
> > 1+0 records out
> > 1024 bytes transferred in 0.000603 secs (1697756 bytes/sec)
> > 00000000  fc 31 c0 8e c0 8e d8 8e  d0 bc 00 0e be 1a 7c bf
> > |.1............|.|
> 
> One possibility is that the device doesn't support 6-byte read/write
> requests.  The da(4) driver has quirk entries and code to figure that out
> and default to 10-byte read/write requests, but camdd(8) doesn't have
> anything like that yet.
> 
> I've attached patches to camdd that allow you to specify a minimum
> command size.  So, apply the patches, rebuild camdd, and try this:
> 
> # sudo camdd -i pass=da0,bs=65536,mcs=10 -o file=blafsel.img
> 
> We'll see if that helps.  I'm not sure why you were even able to get 13
> bytes back.  That is very strange.

With the patch, reading from da0 seems to work until the end,
but again only 13 bytes are written out when writing to a file:

[fk_at_kendra ~]$ sudo camdd -i pass=da0,bs=65536,mcs=10 -o file=blafsel.img
(pass2:umass-sim0:0:0:0): READ(10). CDB: 28 00 00 78 a8 00 00 00 00 00
(pass2:umass-sim0:0:0:0): CAM status: CCB request completed with an error
4048551936 bytes read from pass2
13 bytes written to blafsel.img
127.6488 seconds elapsed
0.00 MB/sec
[fk_at_kendra ~]$ diskinfo -v /dev/da0
/dev/da0
        512             # sectorsize
        4048551936      # mediasize in bytes (3.8G)
        7907328         # mediasize in sectors
        0               # stripesize
        0               # stripeoffset
        492             # Cylinders according to firmware.
        255             # Heads according to firmware.
        63              # Sectors according to firmware.
        AA00000000000958        # Disk ident.

It works as expected when writing to stdout, though, so this is
probably just a camdd-internal issue:

[fk_at_kendra ~]$ sudo camdd -i pass=da0,bs=65536,mcs=10 -o file=- > /dpool/scratch/blafasel.img
(pass2:umass-sim0:0:0:0): READ(10). CDB: 28 00 00 78 a8 00 00 00 00 00
(pass2:umass-sim0:0:0:0): CAM status: CCB request completed with an error
4048551936 bytes read from pass2
4048551936 bytes written to -
128.7222 seconds elapsed
29.99 MB/sec

[fk_at_kendra ~]$ sudo dd if=/dev/da0 bs=65536 of=/dpool/scratch/blafasel-dd.img
61776+0 records in
61776+0 records out
4048551936 bytes transferred in 134.993030 secs (29990822 bytes/sec)

[fk_at_kendra ~]$ sha1 /dpool/scratch/blafasel*.img
SHA1 (/dpool/scratch/blafasel-dd.img) = 12d1d9e82f840a6c6485ffcdb1fbf780266ed266
SHA1 (/dpool/scratch/blafasel.img) = 12d1d9e82f840a6c6485ffcdb1fbf780266ed266

Looks good to me.

Fabian