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[thirdparty/mdadm.git] / bitmap.c

/*
 * 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"

static 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);
        sb->nodes = __le32_to_cpu(sb->nodes);
        sb->sectors_reserved = __le32_to_cpu(sb->sectors_reserved);
}

static 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        { "Out of date", 2 },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 }
};

static const char *bitmap_state(int state_num)
{
        char *state = map_num(bitmap_states, state_num);
        return state ? state : "Unknown";
}

static 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 */
static 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;
}

static 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;
}

static 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, 8192) != 0) {
                pr_err("failed to allocate 8192 bytes\n");
                return NULL;
        }
        n = read(fd, buf, 8192);

        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;
}

static int
bitmap_file_open(char *filename, struct supertype **stp, int node_num)
{
        int fd;
        struct supertype *st = *stp;

        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;
        }

        if (fstat_is_blkdev(fd, filename, NULL)) {
                /* 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);
                        close(fd);
                        return -1;
                } else {
                        if (st->ss->locate_bitmap(st, fd, node_num)) {
                                pr_err("%s doesn't have bitmap\n", filename);
                                close(fd);
                                fd = -1;
                        }
                }

                *stp = st;
        } else {
                close(fd);
                return -1;
        }

        return fd;
}

static __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, 0);
        if (fd < 0)
                return rv;

        info = bitmap_fd_read(fd, brief);
        if (!info)
                return rv;
        sb = &info->sb;
        if (sb->magic != BITMAP_MAGIC) {
                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_CLUSTERED) {
                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]);

        if (sb->nodes == 0) {
                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));

        }

        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) {
                if (brief)
                        goto free_info;
                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));
        } else {
                printf("   Cluster nodes : %d\n", sb->nodes);
                printf("    Cluster name : %-64s\n", sb->cluster_name);
                for (i = 0; i < (int)sb->nodes; i++) {
                        st = NULL;
                        free(info);
                        fd = bitmap_file_open(filename, &st, i);
                        if (fd < 0) {
                                printf("   Unable to open bitmap file on node: %i\n", i);

                                continue;
                        }
                        info = bitmap_fd_read(fd, brief);
                        if (!info) {
                                close(fd);
                                printf("   Unable to read bitmap on node: %i\n", i);
                                continue;
                        }
                        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));
                         close(fd);
                }
        }

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;
}