[PATCH] set request fastfail bit

[PATCH] set request fastfail bit

[Mike Christie]

[-- Attachment #1: Type: text/plain, Size: 329 bytes --]

The first three bio and request flags are no longer identical.
The bio barrier and rw flags are getting set in __make_request
and get_request respectively, and failfast is getting
left out. The attached patch (built against 2.6.4-rc3)
sets the request's failfast flag in __make_request when the bio's
flag is set.

Mike Chrisite

[-- Attachment #2: failfast.patch --]
[-- Type: text/plain, Size: 943 bytes --]

--- linux-2.6.4-rc3-orig/drivers/block/ll_rw_blk.c	2004-03-09 22:21:26.819208694 -0800
+++ linux-2.6.4-rc3-ff/drivers/block/ll_rw_blk.c	2004-03-09 22:37:02.395169904 -0800
@@ -2121,11 +2121,14 @@ get_rq:
 		goto again;
 	}
 
+	req->flags |= REQ_CMD;
+
 	/*
-	 * first three bits are identical in rq->flags and bio->bi_rw,
-	 * see bio.h and blkdev.h
+	 * inherit FAILFAST from bio and don't stack up
+	 * retries for read ahead
 	 */
-	req->flags = (bio->bi_rw & 7) | REQ_CMD;
+	if (ra || test_bit(BIO_RW_FAILFAST, &bio->bi_rw))	
+		req->flags |= REQ_FAILFAST;
 
 	/*
 	 * REQ_BARRIER implies no merging, but lets make it explicit
@@ -2133,12 +2136,6 @@ get_rq:
 	if (barrier)
 		req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
 
-	/*
-	 * don't stack up retries for read ahead
-	 */
-	if (ra)
-		req->flags |= REQ_FAILFAST;
-
 	req->errors = 0;
 	req->hard_sector = req->sector = sector;
 	req->hard_nr_sectors = req->nr_sectors = nr_sectors;

Re: [PATCH] set request fastfail bit

[Mike Christie]

Mike Christie wrote:
> The first three bio and request flags are no longer identical.
> The bio barrier and rw flags are getting set in __make_request
       ^^^

That should have said request not bio.

> and get_request respectively, and failfast is getting
> left out. The attached patch (built against 2.6.4-rc3)
> sets the request's failfast flag in __make_request when the bio's
> flag is set.

Re: [PATCH] set request fastfail bit

[Jens Axboe]

On Tue, Mar 09 2004, Mike Christie wrote:
> The first three bio and request flags are no longer identical.
> The bio barrier and rw flags are getting set in __make_request
> and get_request respectively, and failfast is getting
> left out. The attached patch (built against 2.6.4-rc3)
> sets the request's failfast flag in __make_request when the bio's
> flag is set.
> 
> Mike Chrisite

> --- linux-2.6.4-rc3-orig/drivers/block/ll_rw_blk.c	2004-03-09 22:21:26.819208694 -0800
> +++ linux-2.6.4-rc3-ff/drivers/block/ll_rw_blk.c	2004-03-09 22:37:02.395169904 -0800
> @@ -2121,11 +2121,14 @@ get_rq:
>  		goto again;
>  	}
>  
> +	req->flags |= REQ_CMD;
> +
>  	/*
> -	 * first three bits are identical in rq->flags and bio->bi_rw,
> -	 * see bio.h and blkdev.h
> +	 * inherit FAILFAST from bio and don't stack up
> +	 * retries for read ahead
>  	 */
> -	req->flags = (bio->bi_rw & 7) | REQ_CMD;
> +	if (ra || test_bit(BIO_RW_FAILFAST, &bio->bi_rw))	
> +		req->flags |= REQ_FAILFAST;
>  
>  	/*
>  	 * REQ_BARRIER implies no merging, but lets make it explicit
> @@ -2133,12 +2136,6 @@ get_rq:
>  	if (barrier)
>  		req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
>  
> -	/*
> -	 * don't stack up retries for read ahead
> -	 */
> -	if (ra)
> -		req->flags |= REQ_FAILFAST;
> -
>  	req->errors = 0;
>  	req->hard_sector = req->sector = sector;
>  	req->hard_nr_sectors = req->nr_sectors = nr_sectors;

Thanks Mike, patch looks good.

-- 
Jens Axboe