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