Use kernel RAID6 galois tables for later RAID6 recovery.
Galois tables file, kernel-lib/tables.c is generated by user space
program, mktable.
Galois field tables declaration, in kernel-lib/raid56.h, is completely
copied from kernel.
The mktables.c is copied from kernel with minor header/macro
modification, to ensure the generated tables.c works well in
btrfs-progs.
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
.gitignore | 2 +
Makefile | 13 ++++-
kernel-lib/mktables.c | 148 ++++++++++++++++++++++++++++++++++++++++++++++++++
kernel-lib/raid56.h | 12 ++++
4 files changed, 173 insertions(+), 2 deletions(-)
create mode 100644 kernel-lib/mktables.c
diff --git a/.gitignore b/.gitignore
index 43c0ed88..7d7a5482 100644
--- a/.gitignore
+++ b/.gitignore
@@ -35,6 +35,8 @@ btrfs-select-super
btrfs-calc-size
btrfs-crc
btrfstune
+mktables
+kernel-lib/tables.c
libbtrfs.a
libbtrfs.so
libbtrfs.so.0
diff --git a/Makefile b/Makefile
index 92063a90..ba73357b 100644
--- a/Makefile
+++ b/Makefile
@@ -95,7 +95,7 @@ objects = ctree.o disk-io.o kernel-lib/radix-tree.o
extent-tree.o print-tree.o \
qgroup.o raid56.o free-space-cache.o kernel-lib/list_sort.o props.o \
kernel-shared/ulist.o qgroup-verify.o backref.o string-table.o
task-utils.o \
inode.o file.o find-root.o free-space-tree.o help.o send-dump.o \
- fsfeatures.o
+ fsfeatures.o kernel-lib/tables.o
cmds_objects = cmds-subvolume.o cmds-filesystem.o cmds-device.o cmds-scrub.o \
cmds-inspect.o cmds-balance.o cmds-send.o cmds-receive.o \
cmds-quota.o cmds-qgroup.o cmds-replace.o cmds-check.o \
@@ -314,6 +314,14 @@ version.h: version.sh version.h.in configure.ac
@echo " [SH] $@"
$(Q)bash ./config.status --silent $@
+mktables: kernel-lib/mktables.c
+ @echo " [CC] $@"
+ $(Q)$(CC) $(CFLAGS) $< -o $@
+
+kernel-lib/tables.c: mktables
+ @echo " [TABLE] $@"
+ $(Q)./mktables > $@ || ($(RM) -f $@ && exit 1)
+
libbtrfs: $(libs_shared) $(lib_links)
$(libs_shared): $(libbtrfs_objects) $(lib_links) send.h
@@ -503,11 +511,12 @@ clean: $(CLEANDIRS)
$(Q)$(RM) -f -- $(progs) *.o *.o.d \
kernel-lib/*.o kernel-lib/*.o.d \
kernel-shared/*.o kernel-shared/*.o.d \
+ kernel-lib/tables.c\
image/*.o image/*.o.d \
convert/*.o convert/*.o.d \
mkfs/*.o mkfs/*.o.d \
dir-test ioctl-test quick-test library-test library-test-static \
- btrfs.static mkfs.btrfs.static fssum \
+ mktables btrfs.static mkfs.btrfs.static fssum \
$(check_defs) \
$(libs) $(lib_links) \
$(progs_static) $(progs_extra)
diff --git a/kernel-lib/mktables.c b/kernel-lib/mktables.c
new file mode 100644
index 00000000..85f621fe
--- /dev/null
+++ b/kernel-lib/mktables.c
@@ -0,0 +1,148 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ * Copyright 2002-2007 H. Peter Anvin - All Rights Reserved
+ *
+ * This file is part of the Linux kernel, and is made available under
+ * the terms of the GNU General Public License version 2 or (at your
+ * option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * mktables.c
+ *
+ * Make RAID-6 tables. This is a host user space program to be run at
+ * compile time.
+ */
+
+/*
+ * Btrfs-progs port, with following minor fixes:
+ * 1) Use "kerncompat.h"
+ * 2) Get rid of __KERNEL__ related macros
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <time.h>
+
+static uint8_t gfmul(uint8_t a, uint8_t b)
+{
+ uint8_t v = 0;
+
+ while (b) {
+ if (b & 1)
+ v ^= a;
+ a = (a << 1) ^ (a & 0x80 ? 0x1d : 0);
+ b >>= 1;
+ }
+
+ return v;
+}
+
+static uint8_t gfpow(uint8_t a, int b)
+{
+ uint8_t v = 1;
+
+ b %= 255;
+ if (b < 0)
+ b += 255;
+
+ while (b) {
+ if (b & 1)
+ v = gfmul(v, a);
+ a = gfmul(a, a);
+ b >>= 1;
+ }
+
+ return v;
+}
+
+int main(int argc, char *argv[])
+{
+ int i, j, k;
+ uint8_t v;
+ uint8_t exptbl[256], invtbl[256];
+
+ printf("#include \"kerncompat.h\"\n");
+
+ /* Compute multiplication table */
+ printf("\nconst u8 __attribute__((aligned(256)))\n"
+ "raid6_gfmul[256][256] =\n"
+ "{\n");
+ for (i = 0; i < 256; i++) {
+ printf("\t{\n");
+ for (j = 0; j < 256; j += 8) {
+ printf("\t\t");
+ for (k = 0; k < 8; k++)
+ printf("0x%02x,%c", gfmul(i, j + k),
+ (k == 7) ? '\n' : ' ');
+ }
+ printf("\t},\n");
+ }
+ printf("};\n");
+
+ /* Compute vector multiplication table */
+ printf("\nconst u8 __attribute__((aligned(256)))\n"
+ "raid6_vgfmul[256][32] =\n"
+ "{\n");
+ for (i = 0; i < 256; i++) {
+ printf("\t{\n");
+ for (j = 0; j < 16; j += 8) {
+ printf("\t\t");
+ for (k = 0; k < 8; k++)
+ printf("0x%02x,%c", gfmul(i, j + k),
+ (k == 7) ? '\n' : ' ');
+ }
+ for (j = 0; j < 16; j += 8) {
+ printf("\t\t");
+ for (k = 0; k < 8; k++)
+ printf("0x%02x,%c", gfmul(i, (j + k) << 4),
+ (k == 7) ? '\n' : ' ');
+ }
+ printf("\t},\n");
+ }
+ printf("};\n");
+
+ /* Compute power-of-2 table (exponent) */
+ v = 1;
+ printf("\nconst u8 __attribute__((aligned(256)))\n"
+ "raid6_gfexp[256] =\n" "{\n");
+ for (i = 0; i < 256; i += 8) {
+ printf("\t");
+ for (j = 0; j < 8; j++) {
+ exptbl[i + j] = v;
+ printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
+ v = gfmul(v, 2);
+ if (v == 1)
+ v = 0; /* For entry 255, not a real entry */
+ }
+ }
+ printf("};\n");
+
+ /* Compute inverse table x^-1 == x^254 */
+ printf("\nconst u8 __attribute__((aligned(256)))\n"
+ "raid6_gfinv[256] =\n" "{\n");
+ for (i = 0; i < 256; i += 8) {
+ printf("\t");
+ for (j = 0; j < 8; j++) {
+ invtbl[i + j] = v = gfpow(i + j, 254);
+ printf("0x%02x,%c", v, (j == 7) ? '\n' : ' ');
+ }
+ }
+ printf("};\n");
+
+ /* Compute inv(2^x + 1) (exponent-xor-inverse) table */
+ printf("\nconst u8 __attribute__((aligned(256)))\n"
+ "raid6_gfexi[256] =\n" "{\n");
+ for (i = 0; i < 256; i += 8) {
+ printf("\t");
+ for (j = 0; j < 8; j++)
+ printf("0x%02x,%c", invtbl[exptbl[i + j] ^ 1],
+ (j == 7) ? '\n' : ' ');
+ }
+ printf("};\n");
+
+ return 0;
+}
diff --git a/kernel-lib/raid56.h b/kernel-lib/raid56.h
index fa8fa260..030b0afb 100644
--- a/kernel-lib/raid56.h
+++ b/kernel-lib/raid56.h
@@ -25,4 +25,16 @@
void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs);
int raid5_gen_result(int nr_devs, size_t stripe_len, int dest, void **data);
+
+/*
+ * Headers synchronized from kernel include/linux/raid/pq.h
+ * No modification at all.
+ *
+ * Galois field tables.
+ */
+extern const u8 raid6_gfmul[256][256] __attribute__((aligned(256)));
+extern const u8 raid6_vgfmul[256][32] __attribute__((aligned(256)));
+extern const u8 raid6_gfexp[256] __attribute__((aligned(256)));
+extern const u8 raid6_gfinv[256] __attribute__((aligned(256)));
+extern const u8 raid6_gfexi[256] __attribute__((aligned(256)));
#endif
--
2.13.0
--
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