linux/fs/ceph/mdsmap.c
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   1#include <linux/ceph/ceph_debug.h>
   2
   3#include <linux/bug.h>
   4#include <linux/err.h>
   5#include <linux/random.h>
   6#include <linux/slab.h>
   7#include <linux/types.h>
   8
   9#include <linux/ceph/mdsmap.h>
  10#include <linux/ceph/messenger.h>
  11#include <linux/ceph/decode.h>
  12
  13#include "super.h"
  14
  15
  16/*
  17 * choose a random mds that is "up" (i.e. has a state > 0), or -1.
  18 */
  19int ceph_mdsmap_get_random_mds(struct ceph_mdsmap *m)
  20{
  21        int n = 0;
  22        int i;
  23
  24        /* special case for one mds */
  25        if (1 == m->m_max_mds && m->m_info[0].state > 0)
  26                return 0;
  27
  28        /* count */
  29        for (i = 0; i < m->m_max_mds; i++)
  30                if (m->m_info[i].state > 0)
  31                        n++;
  32        if (n == 0)
  33                return -1;
  34
  35        /* pick */
  36        n = prandom_u32() % n;
  37        i = 0;
  38        for (i = 0; n > 0; i++, n--)
  39                while (m->m_info[i].state <= 0)
  40                        i++;
  41
  42        return i;
  43}
  44
  45/*
  46 * Decode an MDS map
  47 *
  48 * Ignore any fields we don't care about (there are quite a few of
  49 * them).
  50 */
  51struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
  52{
  53        struct ceph_mdsmap *m;
  54        const void *start = *p;
  55        int i, j, n;
  56        int err = -EINVAL;
  57        u16 version;
  58
  59        m = kzalloc(sizeof(*m), GFP_NOFS);
  60        if (m == NULL)
  61                return ERR_PTR(-ENOMEM);
  62
  63        ceph_decode_16_safe(p, end, version, bad);
  64        if (version > 3) {
  65                pr_warning("got mdsmap version %d > 3, failing", version);
  66                goto bad;
  67        }
  68
  69        ceph_decode_need(p, end, 8*sizeof(u32) + sizeof(u64), bad);
  70        m->m_epoch = ceph_decode_32(p);
  71        m->m_client_epoch = ceph_decode_32(p);
  72        m->m_last_failure = ceph_decode_32(p);
  73        m->m_root = ceph_decode_32(p);
  74        m->m_session_timeout = ceph_decode_32(p);
  75        m->m_session_autoclose = ceph_decode_32(p);
  76        m->m_max_file_size = ceph_decode_64(p);
  77        m->m_max_mds = ceph_decode_32(p);
  78
  79        m->m_info = kcalloc(m->m_max_mds, sizeof(*m->m_info), GFP_NOFS);
  80        if (m->m_info == NULL)
  81                goto badmem;
  82
  83        /* pick out active nodes from mds_info (state > 0) */
  84        n = ceph_decode_32(p);
  85        for (i = 0; i < n; i++) {
  86                u64 global_id;
  87                u32 namelen;
  88                s32 mds, inc, state;
  89                u64 state_seq;
  90                u8 infoversion;
  91                struct ceph_entity_addr addr;
  92                u32 num_export_targets;
  93                void *pexport_targets = NULL;
  94                struct ceph_timespec laggy_since;
  95                struct ceph_mds_info *info;
  96
  97                ceph_decode_need(p, end, sizeof(u64)*2 + 1 + sizeof(u32), bad);
  98                global_id = ceph_decode_64(p);
  99                infoversion = ceph_decode_8(p);
 100                *p += sizeof(u64);
 101                namelen = ceph_decode_32(p);  /* skip mds name */
 102                *p += namelen;
 103
 104                ceph_decode_need(p, end,
 105                                 4*sizeof(u32) + sizeof(u64) +
 106                                 sizeof(addr) + sizeof(struct ceph_timespec),
 107                                 bad);
 108                mds = ceph_decode_32(p);
 109                inc = ceph_decode_32(p);
 110                state = ceph_decode_32(p);
 111                state_seq = ceph_decode_64(p);
 112                ceph_decode_copy(p, &addr, sizeof(addr));
 113                ceph_decode_addr(&addr);
 114                ceph_decode_copy(p, &laggy_since, sizeof(laggy_since));
 115                *p += sizeof(u32);
 116                ceph_decode_32_safe(p, end, namelen, bad);
 117                *p += namelen;
 118                if (infoversion >= 2) {
 119                        ceph_decode_32_safe(p, end, num_export_targets, bad);
 120                        pexport_targets = *p;
 121                        *p += num_export_targets * sizeof(u32);
 122                } else {
 123                        num_export_targets = 0;
 124                }
 125
 126                dout("mdsmap_decode %d/%d %lld mds%d.%d %s %s\n",
 127                     i+1, n, global_id, mds, inc,
 128                     ceph_pr_addr(&addr.in_addr),
 129                     ceph_mds_state_name(state));
 130
 131                if (mds < 0 || mds >= m->m_max_mds || state <= 0)
 132                        continue;
 133
 134                info = &m->m_info[mds];
 135                info->global_id = global_id;
 136                info->state = state;
 137                info->addr = addr;
 138                info->laggy = (laggy_since.tv_sec != 0 ||
 139                               laggy_since.tv_nsec != 0);
 140                info->num_export_targets = num_export_targets;
 141                if (num_export_targets) {
 142                        info->export_targets = kcalloc(num_export_targets,
 143                                                       sizeof(u32), GFP_NOFS);
 144                        if (info->export_targets == NULL)
 145                                goto badmem;
 146                        for (j = 0; j < num_export_targets; j++)
 147                                info->export_targets[j] =
 148                                       ceph_decode_32(&pexport_targets);
 149                } else {
 150                        info->export_targets = NULL;
 151                }
 152        }
 153
 154        /* pg_pools */
 155        ceph_decode_32_safe(p, end, n, bad);
 156        m->m_num_data_pg_pools = n;
 157        m->m_data_pg_pools = kcalloc(n, sizeof(u64), GFP_NOFS);
 158        if (!m->m_data_pg_pools)
 159                goto badmem;
 160        ceph_decode_need(p, end, sizeof(u64)*(n+1), bad);
 161        for (i = 0; i < n; i++)
 162                m->m_data_pg_pools[i] = ceph_decode_64(p);
 163        m->m_cas_pg_pool = ceph_decode_64(p);
 164
 165        /* ok, we don't care about the rest. */
 166        dout("mdsmap_decode success epoch %u\n", m->m_epoch);
 167        return m;
 168
 169badmem:
 170        err = -ENOMEM;
 171bad:
 172        pr_err("corrupt mdsmap\n");
 173        print_hex_dump(KERN_DEBUG, "mdsmap: ",
 174                       DUMP_PREFIX_OFFSET, 16, 1,
 175                       start, end - start, true);
 176        ceph_mdsmap_destroy(m);
 177        return ERR_PTR(err);
 178}
 179
 180void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
 181{
 182        int i;
 183
 184        for (i = 0; i < m->m_max_mds; i++)
 185                kfree(m->m_info[i].export_targets);
 186        kfree(m->m_info);
 187        kfree(m->m_data_pg_pools);
 188        kfree(m);
 189}
 190
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