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

[Hubert Verstraete <hubskml@xxxxxxx>]

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