zfs: Fix libblkid detection (backport from upstream)

This fixes issues with importing ZFS pools, such as when the ZFS device is a
partition that covers the end of the disk.

See: https://github.com/zfsonlinux/zfs/issues/1684

pkgs/os-specific/linux/zfs/default.nix

@@ -8,7 +8,7 @@ stdenv.mkDerivation {
     sha256 = "18b5f18k8mwb17r5ippsilmp1a2sqjw9fwn0z82159dkhsadg33b";
   };
 
-  patches = [ ./mount_zfs_prefix.patch ./nix-build.patch ];
+  patches = [ ./mount_zfs_prefix.patch ./nix-build.patch ./libblkid-1db7b9b.patch ];
 
   buildInputs = [ spl perl autoconf automake libtool zlib libuuid coreutils ];
 

pkgs/os-specific/linux/zfs/libblkid-1db7b9b.patch

@@ -0,0 +1,118 @@
+commit 1db7b9be75a225cedb3b7a60028ca5695e5b8346
+Author: Richard Yao <ryao@gentoo.org>
+Date:   Wed Aug 28 16:17:47 2013 -0400
+
+    Fix libblkid support
+    
+    libblkid support is dormant because the autotools check is broken and
+    liblkid identifies ZFS vdevs as "zfs_member", not "zfs". We fix that
+    with a few changes:
+    
+    First, we fix the libblkid autotools check to do a few things:
+    
+    1. Make a 64MB file, which is the minimum size ZFS permits.
+    2. Make 4 fake uberblock entries to make libblkid's check succeed.
+    3. Return 0 upon success to make autotools use the success case.
+    4. Include stdlib.h to avoid implicit declration of free().
+    5. Check for "zfs_member", not "zfs"
+    6. Make --with-blkid disable autotools check (avoids Gentoo sandbox violation)
+    7. Pass '-lblkid' correctly using LIBS not LDFLAGS.
+    
+    Second, we change the libblkid support to scan for "zfs_member", not
+    "zfs".
+    
+    This makes --with-blkid work on Gentoo.
+    
+    Signed-off-by: Richard Yao <ryao@gentoo.org>
+    Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
+    Issue #1751
+
+diff --git a/config/user-libblkid.m4 b/config/user-libblkid.m4
+index 276587f..2dd2623 100644
+--- a/config/user-libblkid.m4
++++ b/config/user-libblkid.m4
+@@ -22,26 +22,45 @@ AC_DEFUN([ZFS_AC_CONFIG_USER_LIBBLKID], [
+ 		[with_blkid=check])
+ 
+ 	LIBBLKID=
+-	AS_IF([test "x$with_blkid" != xno],
++	AS_IF([test "x$with_blkid" = xyes],
++	[
++		AC_SUBST([LIBBLKID], ["-lblkid"])
++		AC_DEFINE([HAVE_LIBBLKID], 1,
++			[Define if you have libblkid])
++	])
++
++	AS_IF([test "x$with_blkid" = xcheck],
+ 	[
+ 		AC_CHECK_LIB([blkid], [blkid_get_cache],
+ 		[
+ 			AC_MSG_CHECKING([for blkid zfs support])
+ 
+ 			ZFS_DEV=`mktemp`
+-			dd if=/dev/zero of=$ZFS_DEV bs=1024k count=8 \
++			truncate -s 64M $ZFS_DEV
++			echo -en "\x0c\xb1\xba\0\0\0\0\0" | \
++				dd of=$ZFS_DEV bs=1k count=8 \
++				seek=128 conv=notrunc &>/dev/null \
+ 				>/dev/null 2>/dev/null
+ 			echo -en "\x0c\xb1\xba\0\0\0\0\0" | \
+ 				dd of=$ZFS_DEV bs=1k count=8 \
+ 				seek=132 conv=notrunc &>/dev/null \
+ 				>/dev/null 2>/dev/null
++			echo -en "\x0c\xb1\xba\0\0\0\0\0" | \
++				dd of=$ZFS_DEV bs=1k count=8 \
++				seek=136 conv=notrunc &>/dev/null \
++				>/dev/null 2>/dev/null
++			echo -en "\x0c\xb1\xba\0\0\0\0\0" | \
++				dd of=$ZFS_DEV bs=1k count=8 \
++				seek=140 conv=notrunc &>/dev/null \
++				>/dev/null 2>/dev/null
+ 
+-			saved_LDFLAGS="$LDFLAGS"
+-			LDFLAGS="-lblkid"
++			saved_LIBS="$LIBS"
++			LIBS="-lblkid"
+ 
+ 			AC_RUN_IFELSE([AC_LANG_PROGRAM(
+ 			[
+ 				#include <stdio.h>
++				#include <stdlib.h>
+ 				#include <blkid/blkid.h>
+ 			],
+ 			[
+@@ -58,10 +77,10 @@ AC_DEFUN([ZFS_AC_CONFIG_USER_LIBBLKID], [
+ 					return 2;
+ 				}
+ 
+-				if (strcmp(value, "zfs")) {
++				if (strcmp(value, "zfs_member")) {
+ 					free(value);
+ 					blkid_put_cache(cache);
+-					return 3;
++					return 0;
+ 				}
+ 
+ 				free(value);
+@@ -82,7 +101,7 @@ AC_DEFUN([ZFS_AC_CONFIG_USER_LIBBLKID], [
+ 					[--with-blkid given but unavailable])])
+ 			])
+ 
+-			LDFLAGS="$saved_LDFLAGS"
++			LIBS="$saved_LIBS"
+ 		],
+ 		[
+ 			AS_IF([test "x$with_blkid" != xcheck],
+diff --git a/lib/libzfs/libzfs_import.c b/lib/libzfs/libzfs_import.c
+index 53609f2..d1fa98e 100644
+--- a/lib/libzfs/libzfs_import.c
++++ b/lib/libzfs/libzfs_import.c
+@@ -965,7 +965,7 @@ zpool_find_import_blkid(libzfs_handle_t *hdl, pool_list_t *pools)
+ 		goto err_blkid2;
+ 	}
+ 
+-	err = blkid_dev_set_search(iter, "TYPE", "zfs");
++	err = blkid_dev_set_search(iter, "TYPE", "zfs_member");
+ 	if (err != 0) {
+ 		(void) zfs_error_fmt(hdl, EZFS_BADCACHE,
+ 		    dgettext(TEXT_DOMAIN, "blkid_dev_set_search() %d"), err);