Re: [PATCH] XFS tuning on software RAID5 partitionable array; error in xfsprogs 2.9.8

[Hubert Verstraete <hubskml@free.fr>]

Hello

First, thank you for including the patch in xfsprogs-2.9.8.
I have just reviewed the new source code; unfortunately, I found out a 
change from the original patch that could generate a segmentation fault.

The line 89 in libdisk/md.c is: "free(dfile2);" but it should have 
remained "if (dfile2) free(dfile2);" because dfile2 is null in case 
mkfs.xfs is run on an MD device.

Regards,
Hubert Verstraete

Hubert Verstraete wrote:
> Hi XFS list,
>
> please find attached a patch for libdisk/mkfs.xfs which tunes XFS on 
> software partitionable RAID arrays, also called mdp.
>
> Hubert Verstraete
>
> ------------------------------------------------------------------------
> 
> diff -u -r xfsprogs-2.8.11/libdisk/md.c xfsprogs-2.8.11-mdp/libdisk/md.c
> --- xfsprogs-2.8.11/libdisk/md.c	2006-06-26 07:01:15.000000000 +0200
> +++ xfsprogs-2.8.11-mdp/libdisk/md.c	2008-03-26 20:12:38.000000000 +0100
> @@ -24,8 +24,12 @@
>  	dev_t		dev)
>  {
>  	if (major(dev) == MD_MAJOR)
> -		return 1;
> -	return get_driver_block_major("md", major(dev));
> +		return MD_IS_MD;
> +	if (get_driver_block_major("md", major(dev)))
> +		return MD_IS_MD;
> +	if (get_driver_block_major("mdp", major(dev)))
> +		return MD_IS_MDP;
> +	return 0;
>  }
>  
>  int
> @@ -37,12 +41,32 @@
>  	int		*sectalign,
>  	struct stat64	*sb)
>  {
> -	if (mnt_is_md_subvol(sb->st_rdev)) {
> +	char *pc, *dfile2 = NULL;
> +	int is_md;
> +
> +	if ((is_md = mnt_is_md_subvol(sb->st_rdev))) {
>  		struct md_array_info	md;
>  		int			fd;
>  
> +		if (is_md == MD_IS_MDP) {
> +			if (!(pc = strrchr(dfile, 'd'))
> +			|| !(pc = strchr(pc, 'p'))) {
> +				fprintf(stderr,
> +					_("Error getting MD array device from %s\n"),
> +					dfile);
> +				exit(1);
> +			}
> +			dfile2 = (char *) malloc(pc - dfile + 1);
> +			if (dfile2 == NULL) {
> +				fprintf(stderr,
> +					_("Couldn't malloc device string\n"));
> +				exit(1);
> +			}
> +			strncpy(dfile2, dfile, pc - dfile);
> +			dfile2[pc - dfile + 1] = '\0';
> +		}
>  		/* Open device */
> -		fd = open(dfile, O_RDONLY);
> +		fd = open(dfile2 ? dfile2 : dfile, O_RDONLY);
>  		if (fd == -1)
>  			return 0;
>  
> @@ -50,10 +74,11 @@
>  		if (ioctl(fd, GET_ARRAY_INFO, &md)) {
>  			fprintf(stderr,
>  				_("Error getting MD array info from %s\n"),
> -				dfile);
> +				dfile2 ? dfile2 : dfile);
>  			exit(1);
>  		}
>  		close(fd);
> +		if (dfile2) free(dfile2);
>  
>  		/*
>  		 * Ignore levels we don't want aligned (e.g. linear)
> diff -u -r xfsprogs-2.8.11/libdisk/md.h xfsprogs-2.8.11-mdp/libdisk/md.h
> --- xfsprogs-2.8.11/libdisk/md.h	2006-06-26 07:01:15.000000000 +0200
> +++ xfsprogs-2.8.11-mdp/libdisk/md.h	2008-03-26 20:12:10.000000000 +0100
> @@ -20,6 +20,9 @@
>  #define MD_MAJOR		9 /* we also check at runtime */
>  #endif
>  
> +#define MD_IS_MD		1
> +#define MD_IS_MDP		2
> +
>  #define GET_ARRAY_INFO          _IOR (MD_MAJOR, 0x11, struct md_array_info)
>
>  #define MD_SB_CLEAN		0