Re: 2.6.11-rc[1,2]-mmX scsi cdrom problem, 2.6.10-mm2 ok

Re: 2.6.11-rc[1,2]-mmX scsi cdrom problem, 2.6.10-mm2 ok

[Douglas Gilbert]

[-- Attachment #1: Type: text/plain, Size: 1504 bytes --]

Jens Axboe wrote:
> On Mon, Jan 31 2005, Douglas Gilbert wrote:
> 
>>Jens Axboe wrote:
>>
>>>On Mon, Jan 31 2005, Fabio Coatti wrote:
>>>
>>>
>>>>Alle 09:00, lunedì 31 gennaio 2005, Jens Axboe ha scritto:
>>>>
>>>>
>>>>>>At this point k3b is stuck in D stat, needs reboot.

I was able to replicate this with a USB burner.
My system didn't need a reboot. The "D" state was locked
on "blk_execute_rq". The burner was still accessible via
sg.

>>>>>The most likely suspect is the REQ_BLOCK_PC scsi changes. Can you try
>>>>>2.6.11-rc2-mm1 with bk-scsi backed out? (attached)
>>>>
>>>>just tried, right guess :)
>>>>backing out that patch the problem disappears.
>>>>Let me know if you need to narrow further that issue.
>>>
>>>
>>>Doug, it looks like your REQ_BLOCK_PC changes are buggy. Let me know if
>>>you cannot find the full post and I'll forward it to you.
>>
>>Jens,
>>Hmm. Found the thread on lkml. I got an almost identical
>>lock up in k3b with a USB external cd/dvd drive recently.
>>My laptop didn't need rebooting (probably since the root
>>fs is one an ide disk).
>>
>>That is a quite large patch that you referenced. I'll
>>try and replicate and report back.
> 
> 
> My guess would be the scsi_lib changes, I would suggest you start there.

Indeed. I'm not sure what I was thinking in
scsi_io_completion(). This small reversion
fixes my k3b problem; tested with a USB external
burner.

Signed-off-by: Douglas Gilbert <dougg@torque.net>





[-- Attachment #2: scsi_lib2611rc2bk8.diff --]
[-- Type: text/x-patch, Size: 1233 bytes --]

--- linux/drivers/scsi/scsi_lib.c	2005-01-31 17:46:31.000000000 +1000
+++ linux/drivers/scsi/scsi_lib.c2611r2b8_k3b	2005-01-31 22:46:04.000000000 +1000
@@ -692,6 +692,7 @@
 	int this_count = cmd->bufflen;
 	request_queue_t *q = cmd->device->request_queue;
 	struct request *req = cmd->request;
+	int clear_errors = 1;
 	struct scsi_sense_hdr sshdr;
 	int sense_valid = 0;
 	int sense_deferred = 0;
@@ -721,6 +722,7 @@
 	if (blk_pc_request(req)) { /* SG_IO ioctl from block level */
 		req->errors = result;
 		if (result) {
+			clear_errors = 0;
 			if (sense_valid) {
 				/*
 				 * SG_IO wants current and deferred errors
@@ -745,11 +747,6 @@
 	cmd->request_buffer = NULL;
 	cmd->request_bufflen = 0;
 
-	if (blk_pc_request(req)) { /* SG_IO ioctl from block level */
-		scsi_end_request(cmd, 1, good_bytes, 0);
-		return;
-	}
-
 	/*
 	 * Next deal with any sectors which we were able to correctly
 	 * handle.
@@ -759,7 +756,8 @@
 					      req->nr_sectors, good_bytes));
 		SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg));
 
-		req->errors = 0;
+		if (clear_errors)
+			req->errors = 0;
 		/*
 		 * If multiple sectors are requested in one buffer, then
 		 * they will have been finished off by the first command.

Re: 2.6.11-rc[1,2]-mmX scsi cdrom problem, 2.6.10-mm2 ok

[Jens Axboe]

On Mon, Jan 31 2005, Douglas Gilbert wrote:
> Jens Axboe wrote:
> >On Mon, Jan 31 2005, Douglas Gilbert wrote:
> >
> >>Jens Axboe wrote:
> >>
> >>>On Mon, Jan 31 2005, Fabio Coatti wrote:
> >>>
> >>>
> >>>>Alle 09:00, lunedì 31 gennaio 2005, Jens Axboe ha scritto:
> >>>>
> >>>>
> >>>>>>At this point k3b is stuck in D stat, needs reboot.
> 
> I was able to replicate this with a USB burner.
> My system didn't need a reboot. The "D" state was locked
> on "blk_execute_rq". The burner was still accessible via
> sg.

With a slave burner on the same interface as your hard drive, it would
soft hang the system.

> >>>>>The most likely suspect is the REQ_BLOCK_PC scsi changes. Can you try
> >>>>>2.6.11-rc2-mm1 with bk-scsi backed out? (attached)
> >>>>
> >>>>just tried, right guess :)
> >>>>backing out that patch the problem disappears.
> >>>>Let me know if you need to narrow further that issue.
> >>>
> >>>
> >>>Doug, it looks like your REQ_BLOCK_PC changes are buggy. Let me know if
> >>>you cannot find the full post and I'll forward it to you.
> >>
> >>Jens,
> >>Hmm. Found the thread on lkml. I got an almost identical
> >>lock up in k3b with a USB external cd/dvd drive recently.
> >>My laptop didn't need rebooting (probably since the root
> >>fs is one an ide disk).
> >>
> >>That is a quite large patch that you referenced. I'll
> >>try and replicate and report back.
> >
> >
> >My guess would be the scsi_lib changes, I would suggest you start there.
> 
> Indeed. I'm not sure what I was thinking in
> scsi_io_completion(). This small reversion
> fixes my k3b problem; tested with a USB external
> burner.

Well at least I had hoped you would have tested patches going into
mainline...

Can you make sure it gets to Linus asap? Otherwise I'm sure I'll be
flooded with mails on burning not working very shortly.

-- 
Jens Axboe

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