zfs: add migration path for new crypto format

fixes #34559

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

@@ -5,7 +5,7 @@
 , zlib, libuuid, python, attr, openssl
 
 # Kernel dependencies
-, kernel ? null, spl ? null, splUnstable ? null
+, kernel ? null, spl ? null, splUnstable ? null, splLegacyCrypto ? null
 }:
 
 with stdenv.lib;
@@ -19,6 +19,7 @@ let
     , spl
     , rev ? "zfs-${version}"
     , isUnstable ? false
+    , isLegacyCrypto ? false
     , incompatibleKernelVersion ? null } @ args:
     if buildKernel &&
       (incompatibleKernelVersion != null) &&
@@ -43,7 +44,7 @@ let
       buildInputs =
            optionals buildKernel [ spl ]
         ++ optionals buildUser [ zlib libuuid python attr ]
-        ++ optionals (buildUser && isUnstable) [ openssl ];
+        ++ optionals (buildUser && (isUnstable || isLegacyCrypto)) [ openssl ];
 
       # for zdb to get the rpath to libgcc_s, needed for pthread_cancel to work
       NIX_CFLAGS_LINK = "-lgcc_s";
@@ -160,19 +161,41 @@ in {
     incompatibleKernelVersion = null;
 
     # this package should point to a version / git revision compatible with the latest kernel release
-    version = "2018-01-10";
+    version = "2018-02-02";
 
-    rev = "1d53657bf561564162e2ad6449f80fa0140f1dd6";
-    sha256 = "0ibkhfz06cypgl2c869dzdbdx2i3m8ywwdmnzscv0cin5gm31vhx";
+    rev = "fbd42542686af053f0d162ec4630ffd4fff1cc30";
+    sha256 = "0qzkwnnk7kz1hwvcaqlpzi5yspfhhmd2alklc07k056ddzbx52qb";
     isUnstable = true;
 
     extraPatches = [
       (fetchpatch {
-        url = "https://github.com/Mic92/zfs/compare/ded8f06a3cfee...nixos-zfs-2017-09-12.patch";
-        sha256 = "033wf4jn0h0kp0h47ai98rywnkv5jwvf3xwym30phnaf8xxdx8aj";
+        url = "https://github.com/Mic92/zfs/compare/fbd42542686af053f0d162ec4630ffd4fff1cc30...nixos-zfs-2018-02-02.patch";
+        sha256 = "05wqwjm9648x60vkwxbp8l6z1q73r2a5l2ni28i2f4pla8s3ahln";
       })
     ];
 
     spl = splUnstable;
   };
+
+  zfsLegacyCrypto = common {
+    # comment/uncomment if breaking kernel versions are known
+    incompatibleKernelVersion = null;
+
+    # this package should point to a version / git revision compatible with the latest kernel release
+    version = "2018-02-01";
+
+    rev = "4c46b99d24a6e71b3c72462c11cb051d0930ad60";
+    sha256 = "011lcp2x44jgfzqqk2gjmyii1v7rxcprggv20prxa3c552drsx3c";
+    isUnstable = true;
+
+    extraPatches = [
+      (fetchpatch {
+        url = "https://github.com/Mic92/zfs/compare/4c46b99d24a6e71b3c72462c11cb051d0930ad60...nixos-zfs-2018-02-01.patch";
+        sha256 = "1gqmgqi39qhk5kbbvidh8f2xqq25vj58i9x0wjqvcx6a71qj49ch";
+      })
+    ];
+
+    spl = splLegacyCrypto;
+  };
+
 }