dmraid -r -E bus error

[Hall, Eric R]

Out of curiosity, how is this patch different than the one that Jason
Gaston and Ying Fang released on 29 June 2007 other than it seems to be
more compact? ;)

http://www.redhat.com/archives/ataraid-list/2007-June/msg00037.html

- E

>-----Original Message-----
>From: ataraid-list-bounces at redhat.com [mailto:ataraid-list-
>bounces at redhat.com] On Behalf Of Ian Kent
>Sent: Monday, October 22, 2007 12:16 AM
>To: ataraid-list at redhat.com
>Subject: dmraid -r -E bus error
>
>
>Hi all,
>
>The command "dmraid -r -E <raid dev>" SEGVs if there is a single device
>in in the on disk meta data configuration.
>
>If the on disk meta data configuration contains one raid device only
>(one block only) then the isw module determines there are no extended
>attributes and extra space isn't allocated during the meta data read.
>
>However, the meta data write function fails to check whether the extra
>space is present before copying the meta data and SEGVs when trying to
>write it to the non existent memory.
>
>I consulted with Heinz Mauelshagen and we ended up with this patch.
>Comments welcome.
>
>Ian
>
>---
>diff -up 1.0.0.rc14/lib/format/ataraid/isw.c.solitary-meta-block
>1.0.0.rc14/lib/format/ataraid/isw.c
>--- 1.0.0.rc14/lib/format/ataraid/isw.c.solitary-meta-block
2006-09-23
>02:11:37.000000000 +0800
>+++ 1.0.0.rc14/lib/format/ataraid/isw.c	2007-10-22
15:10:49.000000000
>+0800
>@@ -364,21 +364,26 @@ static int isw_write(struct lib_context
> {
> 	int ret;
> 	struct isw *isw = META(rd, isw);
>+	int large = div_up(isw->mpb_size, ISW_DISK_BLOCK_SIZE) > 1;
>
> 	to_disk(isw, FULL);
>
>-	/*
>-	 * Copy 1st metadata sector to after the extended ones
>-	 * and increment metadata area pointer by one block, so
>-	 * that the metadata is filed in the proper sequence.
>-	 */
>-	memcpy((void*) isw + rd->meta_areas->size, isw,
ISW_DISK_BLOCK_SIZE);
>-	rd->meta_areas->area += ISW_DISK_BLOCK_SIZE;
>+	if (large) {
>+		/*
>+		 * Copy 1st metadata sector to after the extended ones
>+		 * and increment metadata area pointer by one block, so
>+		 * that the metadata is filed in the proper sequence.
>+		 */
>+		memcpy((void*) isw + rd->meta_areas->size, isw,
>+		       ISW_DISK_BLOCK_SIZE);
>+		rd->meta_areas->area += ISW_DISK_BLOCK_SIZE;
>+	}
>
> 	ret = write_metadata(lc, handler, rd, -1, erase);
>
> 	/* Correct metadata area pointer. */
>-	rd->meta_areas->area -= ISW_DISK_BLOCK_SIZE;
>+	if (large)
>+		rd->meta_areas->area -= ISW_DISK_BLOCK_SIZE;
>
> 	to_cpu(isw, FULL);
>
>
>
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