svn commit: r294040 - head/sys/boot/zfs

[Steven Hartland]

Fat fingers submitted before adding headers:

MFC after:	2 weeks
X-MFC-With:	r293268


On 14/01/2016 21:31, Steven Hartland wrote:
> Author: smh
> Date: Thu Jan 14 21:31:26 2016
> New Revision: 294040
> URL: https://svnweb.freebsd.org/changeset/base/294040
>
> Log:
>    Prevent bogus compiler in ZFS boot code
>    
>    Silence a bogus compiler warning about indexing past the end of dn_bonus.
>    
>    The ZFS code ensures this is not possible but the compiler can't determine
>    this so added an additional check to prevent this warning.
>    
>    Sponsored by:	Multiplay
>
> Modified:
>    head/sys/boot/zfs/zfsimpl.c
>
> Modified: head/sys/boot/zfs/zfsimpl.c
> ==============================================================================
> --- head/sys/boot/zfs/zfsimpl.c	Thu Jan 14 21:29:38 2016	(r294039)
> +++ head/sys/boot/zfs/zfsimpl.c	Thu Jan 14 21:31:26 2016	(r294040)
> @@ -2165,7 +2165,13 @@ zfs_lookup(const struct zfsmount *mount,
>   				strcpy(&path[sb.st_size], p);
>   			else
>   				path[sb.st_size] = 0;
> -			if (sb.st_size + sizeof(znode_phys_t) <= dn.dn_bonuslen) {
> +			/*
> +			 * Second test is purely to silence bogus compiler
> +			 * warning about accessing past the end of dn_bonus.
> +			 */
> +			if (sb.st_size + sizeof(znode_phys_t) <=
> +			    dn.dn_bonuslen && sizeof(znode_phys_t) <=
> +			    sizeof(dn.dn_bonus)) {
>   				memcpy(path, &dn.dn_bonus[sizeof(znode_phys_t)],
>   					sb.st_size);
>   			} else {
>