From b3d11925c7d961f4d631d6ebfa87dbc1d05535f1 Mon Sep 17 00:00:00 2001
From: Zach Brown <zab@versity.com>
Date: Wed, 11 Oct 2017 10:57:54 -0700
Subject: [PATCH] scoutfs-utils: add support for format_hash

Calculate the hash of format.h and ioctl.h, put it in the super during
mkfs, and print it out.

Signed-off-by: Zach Brown <zab@versity.com>
---
 utils/Makefile     | 6 +++++-
 utils/src/format.h | 1 +
 utils/src/mkfs.c   | 3 +++
 utils/src/print.c  | 6 ++++--
 4 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/utils/Makefile b/utils/Makefile
index 95cd9434..39cd7202 100644
--- a/utils/Makefile
+++ b/utils/Makefile
@@ -1,5 +1,9 @@
+SCOUTFS_FORMAT_HASH := \
+	$(shell cat src/format.h src/ioctl.h | md5sum | cut -b1-16)
+
 CFLAGS := -Wall -O2 -Werror -D_FILE_OFFSET_BITS=64 -g -msse4.2 \
-	-fno-strict-aliasing
+	-fno-strict-aliasing \
+	-DSCOUTFS_FORMAT_HASH=0x$(SCOUTFS_FORMAT_HASH)LLU
 
 BIN := src/scoutfs
 OBJ := $(patsubst %.c,%.o,$(wildcard src/*.c))
diff --git a/utils/src/format.h b/utils/src/format.h
index 9bc496b3..d9be949b 100644
--- a/utils/src/format.h
+++ b/utils/src/format.h
@@ -430,6 +430,7 @@ struct scoutfs_inet_addr {
 struct scoutfs_super_block {
 	struct scoutfs_block_header hdr;
 	__le64 id;
+	__le64 format_hash;
 	__u8 uuid[SCOUTFS_UUID_BYTES];
 	__le64 next_ino;
 	__le64 next_seq;
diff --git a/utils/src/mkfs.c b/utils/src/mkfs.c
index 4a277c3b..add474f7 100644
--- a/utils/src/mkfs.c
+++ b/utils/src/mkfs.c
@@ -208,6 +208,7 @@ static int write_new_fs(char *path, int fd)
 	pseudo_random_bytes(&super->hdr.fsid, sizeof(super->hdr.fsid));
 	super->hdr.seq = cpu_to_le64(1);
 	super->id = cpu_to_le64(SCOUTFS_SUPER_ID);
+	super->format_hash = cpu_to_le64(SCOUTFS_FORMAT_HASH);
 	uuid_generate(super->uuid);
 	super->next_ino = cpu_to_le64(SCOUTFS_ROOT_INO + 1);
 	super->next_seq = cpu_to_le64(1);
@@ -369,12 +370,14 @@ static int write_new_fs(char *path, int fd)
 	printf("Created scoutfs filesystem:\n"
 	       "  device path:        %s\n"
 	       "  fsid:               %llx\n"
+	       "  format hash:        %llx\n"
 	       "  uuid:               %s\n"
 	       "  device bytes:	      "SIZE_FMT"\n"
 	       "  btree ring blocks:  "SIZE_FMT"\n"
 	       "  usable segments:    "SIZE_FMT"\n",
 		path,
 		le64_to_cpu(super->hdr.fsid),
+		le64_to_cpu(super->format_hash),
 		uuid_str,
 		SIZE_ARGS(size, 1),
 		SIZE_ARGS(le64_to_cpu(super->bring.nr_blocks),
diff --git a/utils/src/print.c b/utils/src/print.c
index e5aba85b..14913067 100644
--- a/utils/src/print.c
+++ b/utils/src/print.c
@@ -551,8 +551,10 @@ static void print_super_block(struct scoutfs_super_block *super, u64 blkno)
 
 	printf("super blkno %llu\n", blkno);
 	print_block_header(&super->hdr);
-	printf("  id %llx uuid %s\n",
-	       le64_to_cpu(super->id), uuid_str);
+	printf("  id %llx format_hash %llx\n"
+	       "  uuid %s\n",
+	       le64_to_cpu(super->id), le64_to_cpu(super->format_hash),
+	       uuid_str);
 
 	/* XXX these are all in a crazy order */
 	printf("  next_ino %llu next_seq %llu next_seg_seq %llu\n"