git: af433832f752 - main - geom_label: Remove an old sysinstall(8) workaround

[Cy Schubert]

In message <202107051517.165FHsfD012512 at gitrepo.freebsd.org>, Jessica 
Clarke wr
ites:
> The branch main has been updated by jrtc27:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=af433832f7520840c22edd1fe1266c1a
> 5cb781ad
>
> commit af433832f7520840c22edd1fe1266c1a5cb781ad
> Author:     Jessica Clarke <jrtc27 at FreeBSD.org>
> AuthorDate: 2021-07-05 15:15:32 +0000
> Commit:     Jessica Clarke <jrtc27 at FreeBSD.org>
> CommitDate: 2021-07-05 15:15:32 +0000
>
>     geom_label: Remove an old sysinstall(8) workaround
>     
>     We removed sysinstall(8) back in 2011, so this workaround should be long
>     since unnecessary. This workaround can end up breaking cases that are
>     hit in the real world, such as dd'ing a small pre-built disk image to a
>     large partition that you intend to grow on first boot and uses a UFS
>     disk label for / in its /etc/fstab (as the only reliable thing a raw UFS
>     image can reference).
>     
>     Reviewed by:    imp, mckusick
>     Differential Revision:  https://reviews.freebsd.org/D30825
> ---
>  sys/geom/label/g_label_ufs.c | 35 +++++------------------------------
>  1 file changed, 5 insertions(+), 30 deletions(-)
>
> diff --git a/sys/geom/label/g_label_ufs.c b/sys/geom/label/g_label_ufs.c
> index ababbaa4b43a..70d59488d7b6 100644
> --- a/sys/geom/label/g_label_ufs.c
> +++ b/sys/geom/label/g_label_ufs.c
> @@ -49,19 +49,8 @@ __FBSDID("$FreeBSD$");
>  #define	G_LABEL_UFS_ID		1
>  
>  /*
> - * G_LABEL_UFS_CMP returns true if difference between provider mediasize
> - * and filesystem size is less than G_LABEL_UFS_MAXDIFF sectors
> - */
> -#define	G_LABEL_UFS_CMP(prov, fsys, size) 			
> 	   \
> -	( abs( ((fsys)->size) - ( (prov)->mediasize / (fsys)->fs_fsize ))  \
> -				< G_LABEL_UFS_MAXDIFF )
> -#define	G_LABEL_UFS_MAXDIFF	0x100
> -
> -/*
> - * Try to find a superblock on the provider. If successful, then
> - * check that the size in the superblock corresponds to the size
> - * of the underlying provider. Finally, look for a volume label
> - * and create an appropriate provider based on that.
> + * Try to find a superblock on the provider. If successful, look for a volum
> e
> + * label and create an appropriate provider based on that.
>   */
>  static void
>  g_label_ufs_taste_common(struct g_consumer *cp, char *label, size_t size, in
> t what)
> @@ -81,24 +70,10 @@ g_label_ufs_taste_common(struct g_consumer *cp, char *lab
> el, size_t size, int wh
>  		return;
>  	}
>  
> -	/*
> -	 * Check for magic. We also need to check if file system size
> -	 * is almost equal to providers size, because sysinstall(8)
> -	 * used to bogusly put first partition at offset 0
> -	 * instead of 16, and glabel/ufs would find file system on slice
> -	 * instead of partition.
> -	 *
> -	 * In addition, media size can be a bit bigger than file system
> -	 * size. For instance, mkuzip can append bytes to align data
> -	 * to large sector size (it improves compression rates).
> -	 */
> -	if (fs->fs_magic == FS_UFS1_MAGIC && fs->fs_fsize > 0 &&
> -	    ( G_LABEL_UFS_CMP(pp, fs, fs_old_size)
> -		|| G_LABEL_UFS_CMP(pp, fs, fs_providersize))) {
> +	/* Check for magic. */
> +	if (fs->fs_magic == FS_UFS1_MAGIC && fs->fs_fsize > 0) {
>  		/* Valid UFS1. */
> -	} else if (fs->fs_magic == FS_UFS2_MAGIC && fs->fs_fsize > 0 &&
> -	    ( G_LABEL_UFS_CMP(pp, fs, fs_size)
> -		|| G_LABEL_UFS_CMP(pp, fs, fs_providersize))) {
> +	} else if (fs->fs_magic == FS_UFS2_MAGIC && fs->fs_fsize > 0) {
>  		/* Valid UFS2. */
>  	} else {
>  		goto out;
>

On one of my machines which uses UFS filesystems (sandbox) also fails:

bob# ls /dev/ufs
s10-amd64	s13-amd64	s13-amd64e	test
s11-amd64	s13-amd64a	s13-amd64f	testa
s12-amd64	s13-amd64d	s13-i386
bob# mount /alt/s11-amd64/root
bob# ls /dev/ufs
s10-amd64	s12-amd64	test
s11-amd64	s13-i386	testa
bob# 

After the mount of /alt/s11-amd64/root, s10-amd64 the s13-* filesystems 
become unavailble  They share the same fdisk slice, using different 
bsdlabel partitions within the slice.

My laptop zfs pool is on a partition in the same slice as its UFS 
filesystems. Looks like once a filesystem on a slice has been mounted, the 
other partitions within the slice are no longer available following this 
commit.


-- 
Cheers,
Cy Schubert <Cy.Schubert at cschubert.com>
FreeBSD UNIX:  <cy at FreeBSD.org>   Web:  https://FreeBSD.org
NTP:           <cy at nwtime.org>    Web:  https://nwtime.org

	The need of the many outweighs the greed of the few.