From 084d1524079ad30bae75c2fdbb7b46e711f46042 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Thu, 25 May 2017 14:21:47 +0800 Subject: [PATCH] btrfs-progs: raid56: Introduce tables for RAID6 recovery 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 Signed-off-by: David Sterba --- .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..5ba32093 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 +#include +#include +#include +#include + +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 0d52f3db..46731bcc 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