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bitmap.c
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bitmap.c
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/*
* mdadm - manage Linux "md" devices aka RAID arrays.
*
* Copyright (C) 2004 Paul Clements, SteelEye Technology, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "mdadm.h"
inline void sb_le_to_cpu(bitmap_super_t *sb)
{
sb->magic = __le32_to_cpu(sb->magic);
sb->version = __le32_to_cpu(sb->version);
/* uuid gets no translation */
sb->events = __le64_to_cpu(sb->events);
sb->events_cleared = __le64_to_cpu(sb->events_cleared);
sb->state = __le32_to_cpu(sb->state);
sb->chunksize = __le32_to_cpu(sb->chunksize);
sb->daemon_sleep = __le32_to_cpu(sb->daemon_sleep);
sb->sync_size = __le64_to_cpu(sb->sync_size);
sb->write_behind = __le32_to_cpu(sb->write_behind);
}
inline void sb_cpu_to_le(bitmap_super_t *sb)
{
sb_le_to_cpu(sb); /* these are really the same thing */
}
mapping_t bitmap_states[] = {
{ "OK", 0 },
{ "Out of date", 2 },
{ NULL, -1 }
};
const char *bitmap_state(int state_num)
{
char *state = map_num(bitmap_states, state_num);
return state ? state : "Unknown";
}
const char *human_chunksize(unsigned long bytes)
{
static char buf[16];
char *suffixes[] = { "B", "KB", "MB", "GB", "TB", NULL };
int i = 0;
while (bytes >> 10) {
bytes >>= 10;
i++;
}
snprintf(buf, sizeof(buf), "%lu %s", bytes, suffixes[i]);
return buf;
}
typedef struct bitmap_info_s {
bitmap_super_t sb;
unsigned long long total_bits;
unsigned long long dirty_bits;
} bitmap_info_t;
/* count the dirty bits in the first num_bits of byte */
inline int count_dirty_bits_byte(char byte, int num_bits)
{
int num = 0;
switch (num_bits) { /* fall through... */
case 8: if (byte & 128) num++;
case 7: if (byte & 64) num++;
case 6: if (byte & 32) num++;
case 5: if (byte & 16) num++;
case 4: if (byte & 8) num++;
case 3: if (byte & 4) num++;
case 2: if (byte & 2) num++;
case 1: if (byte & 1) num++;
default: break;
}
return num;
}
int count_dirty_bits(char *buf, int num_bits)
{
int i, num = 0;
for (i = 0; i < num_bits / 8; i++)
num += count_dirty_bits_byte(buf[i], 8);
if (num_bits % 8) /* not an even byte boundary */
num += count_dirty_bits_byte(buf[i], num_bits % 8);
return num;
}
/* calculate the size of the bitmap given the array size and bitmap chunksize */
unsigned long long bitmap_bits(unsigned long long array_size,
unsigned long chunksize)
{
return (array_size * 512 + chunksize - 1) / chunksize;
}
unsigned long bitmap_sectors(struct bitmap_super_s *bsb)
{
unsigned long long bits = bitmap_bits(__le64_to_cpu(bsb->sync_size),
__le32_to_cpu(bsb->chunksize));
int bits_per_sector = 8*512;
return (bits + bits_per_sector - 1) / bits_per_sector;
}
bitmap_info_t *bitmap_fd_read(int fd, int brief)
{
/* Note: fd might be open O_DIRECT, so we must be
* careful to align reads properly
*/
unsigned long long total_bits = 0, read_bits = 0, dirty_bits = 0;
bitmap_info_t *info;
void *buf;
unsigned int n, skip;
if (posix_memalign(&buf, 4096, 4096) != 0) {
pr_err("failed to allocate 4096 bytes\n");
return NULL;
}
n = read(fd, buf, 4096);
info = xmalloc(sizeof(*info));
if (n < sizeof(info->sb)) {
pr_err("failed to read superblock of bitmap "
"file: %s\n", strerror(errno));
free(info);
free(buf);
return NULL;
}
memcpy(&info->sb, buf, sizeof(info->sb));
skip = sizeof(info->sb);
sb_le_to_cpu(&info->sb); /* convert superblock to CPU byte ordering */
if (brief || info->sb.sync_size == 0 || info->sb.chunksize == 0)
goto out;
/* read the rest of the file counting total bits and dirty bits --
* we stop when either:
* 1) we hit EOF, in which case we assume the rest of the bits (if any)
* are dirty
* 2) we've read the full bitmap, in which case we ignore any trailing
* data in the file
*/
total_bits = bitmap_bits(info->sb.sync_size, info->sb.chunksize);
while(read_bits < total_bits) {
unsigned long long remaining = total_bits - read_bits;
if (n == 0) {
n = read(fd, buf, 8192);
skip = 0;
if (n <= 0)
break;
}
if (remaining > (n-skip) * 8) /* we want the full buffer */
remaining = (n-skip) * 8;
dirty_bits += count_dirty_bits(buf+skip, remaining);
read_bits += remaining;
n = 0;
}
if (read_bits < total_bits) { /* file truncated... */
pr_err("WARNING: bitmap file is not large "
"enough for array size %llu!\n\n",
(unsigned long long)info->sb.sync_size);
total_bits = read_bits;
}
out:
free(buf);
info->total_bits = total_bits;
info->dirty_bits = dirty_bits;
return info;
}
int bitmap_file_open(char *filename, struct supertype **stp)
{
int fd = -1;
struct stat stb;
struct supertype *st = *stp;
if (stat(filename, &stb) < 0) {
pr_err("failed to find file %s: %s\n",
filename, strerror(errno));
return -1;
}
if ((S_IFMT & stb.st_mode) == S_IFBLK) {
fd = open(filename, O_RDONLY|O_DIRECT);
if (fd < 0) {
pr_err("failed to open bitmap file %s: %s\n",
filename, strerror(errno));
return -1;
}
/* block device, so we are probably after an internal bitmap */
if (!st) st = guess_super(fd);
if (!st) {
/* just look at device... */
lseek(fd, 0, 0);
} else if (!st->ss->locate_bitmap) {
pr_err("No bitmap possible with %s metadata\n",
st->ss->name);
return -1;
} else
st->ss->locate_bitmap(st, fd);
*stp = st;
} else {
fd = open(filename, O_RDONLY|O_DIRECT);
if (fd < 0) {
pr_err("failed to open bitmap file %s: %s\n",
filename, strerror(errno));
return -1;
}
}
return fd;
}
__u32 swapl(__u32 l)
{
char *c = (char*)&l;
char t= c[0];
c[0] = c[3];
c[3] = t;
t = c[1];
c[1] = c[2];
c[2] = t;
return l;
}
int ExamineBitmap(char *filename, int brief, struct supertype *st)
{
/*
* Read the bitmap file and display its contents
*/
bitmap_super_t *sb;
bitmap_info_t *info;
int rv = 1;
char buf[64];
int swap;
int fd, i;
__u32 uuid32[4];
fd = bitmap_file_open(filename, &st);
if (fd < 0)
return rv;
info = bitmap_fd_read(fd, brief);
sb = &info->sb;
if (sb->magic != BITMAP_MAGIC && md_get_version(fd) > 0) {
pr_err("This is an md array. To view a bitmap you need to examine\n");
pr_err("a member device, not the array.\n");
pr_err("Reporting bitmap that would be used if this array were used\n");
pr_err("as a member of some other array\n");
}
close(fd);
printf(" Filename : %s\n", filename);
printf(" Magic : %08x\n", sb->magic);
if (sb->magic != BITMAP_MAGIC) {
pr_err("invalid bitmap magic 0x%x, the bitmap file appears\n",
sb->magic);
pr_err("to be corrupted or missing.\n");
}
printf(" Version : %d\n", sb->version);
if (sb->version < BITMAP_MAJOR_LO ||
sb->version > BITMAP_MAJOR_HI) {
pr_err("unknown bitmap version %d, either the bitmap file\n",
sb->version);
pr_err("is corrupted or you need to upgrade your tools\n");
goto free_info;
}
rv = 0;
if (st)
swap = st->ss->swapuuid;
else
#if __BYTE_ORDER == BIG_ENDIAN
swap = 0;
#else
swap = 1;
#endif
memcpy(uuid32, sb->uuid, 16);
if (swap)
printf(" UUID : %08x:%08x:%08x:%08x\n",
swapl(uuid32[0]),
swapl(uuid32[1]),
swapl(uuid32[2]),
swapl(uuid32[3]));
else
printf(" UUID : %08x:%08x:%08x:%08x\n",
uuid32[0],
uuid32[1],
uuid32[2],
uuid32[3]);
printf(" Chunksize : %s\n", human_chunksize(sb->chunksize));
printf(" Daemon : %ds flush period\n", sb->daemon_sleep);
if (sb->write_behind)
sprintf(buf, "Allow write behind, max %d", sb->write_behind);
else
sprintf(buf, "Normal");
printf(" Write Mode : %s\n", buf);
printf(" Sync Size : %llu%s\n", (unsigned long long)sb->sync_size/2,
human_size(sb->sync_size * 512));
if (sb->nodes > 0) {
printf(" Cluster nodes : %d\n", sb->nodes);
printf(" Cluster name : %s\n", sb->cluster_name);
}
i = 0;
do {
if (i) {
free(info);
info = bitmap_fd_read(fd, brief);
sb = &info->sb;
}
if (sb->magic != BITMAP_MAGIC) {
pr_err("invalid bitmap magic 0x%x, the bitmap file appears to be corrupted\n", sb->magic);
}
printf(" Node Slot : %d\n", i);
printf(" Events : %llu\n", (unsigned long long)sb->events);
printf(" Events Cleared : %llu\n", (unsigned long long)sb->events_cleared);
printf(" State : %s\n", bitmap_state(sb->state));
if (brief)
continue;
printf(" Bitmap : %llu bits (chunks), %llu dirty (%2.1f%%)\n",
info->total_bits, info->dirty_bits,
100.0 * info->dirty_bits / (info->total_bits?:1));
} while (++i < (int)sb->nodes);
free_info:
free(info);
return rv;
}
int CreateBitmap(char *filename, int force, char uuid[16],
unsigned long chunksize, unsigned long daemon_sleep,
unsigned long write_behind,
unsigned long long array_size /* sectors */,
int major)
{
/*
* Create a bitmap file with a superblock and (optionally) a full bitmap
*/
FILE *fp;
int rv = 1;
char block[512];
bitmap_super_t sb;
long long bytes, filesize;
if (!force && access(filename, F_OK) == 0) {
pr_err("bitmap file %s already exists, use --force to overwrite\n", filename);
return rv;
}
fp = fopen(filename, "w");
if (fp == NULL) {
pr_err("failed to open bitmap file %s: %s\n",
filename, strerror(errno));
return rv;
}
if (chunksize == UnSet) {
/* We don't want more than 2^21 chunks, as 2^11 fill up one
* 4K page (2 bytes per chunk), and 2^10 address of those
* fill up a 4K indexing page. 2^20 might be safer, especially
* on 64bit hosts, so use that.
*/
chunksize = DEFAULT_BITMAP_CHUNK;
/* <<20 for 2^20 chunks, >>9 to convert bytes to sectors */
while (array_size > ((unsigned long long)chunksize << (20-9)))
chunksize <<= 1;
}
memset(&sb, 0, sizeof(sb));
sb.magic = BITMAP_MAGIC;
sb.version = major;
if (uuid != NULL)
memcpy(sb.uuid, uuid, 16);
sb.chunksize = chunksize;
sb.daemon_sleep = daemon_sleep;
sb.write_behind = write_behind;
sb.sync_size = array_size;
sb_cpu_to_le(&sb); /* convert to on-disk byte ordering */
if (fwrite(&sb, sizeof(sb), 1, fp) != 1) {
pr_err("failed to write superblock to bitmap file %s: %s\n", filename, strerror(errno));
goto out;
}
/* calculate the size of the bitmap and write it to disk */
bytes = (bitmap_bits(array_size, chunksize) + 7) / 8;
if (!bytes) {
rv = 0;
goto out;
}
filesize = bytes + sizeof(sb);
memset(block, 0xff, sizeof(block));
while (bytes > 0) {
if (fwrite(block, sizeof(block), 1, fp) != 1) {
pr_err("failed to write bitmap file %s: %s\n", filename, strerror(errno));
goto out;
}
bytes -= sizeof(block);
}
rv = 0;
fflush(fp);
/* make the file be the right size (well, to the nearest byte) */
if (ftruncate(fileno(fp), filesize))
perror("ftrunace");
out:
fclose(fp);
if (rv)
unlink(filename); /* possibly corrupted, better get rid of it */
return rv;
}
int bitmap_update_uuid(int fd, int *uuid, int swap)
{
struct bitmap_super_s bm;
if (lseek(fd, 0, 0) != 0)
return 1;
if (read(fd, &bm, sizeof(bm)) != sizeof(bm))
return 1;
if (bm.magic != __cpu_to_le32(BITMAP_MAGIC))
return 1;
copy_uuid(bm.uuid, uuid, swap);
if (lseek(fd, 0, 0) != 0)
return 2;
if (write(fd, &bm, sizeof(bm)) != sizeof(bm)) {
lseek(fd, 0, 0);
return 2;
}
lseek(fd, 0, 0);
return 0;
}