fs/ceph/mdsmap.c

   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  */
  19 int 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  */
  51 struct 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         u8 mdsmap_v, mdsmap_cv;
  58
  59         m = kzalloc(sizeof(*m), GFP_NOFS);
  60         if (m == NULL)
  61                 return ERR_PTR(-ENOMEM);
  62
  63         ceph_decode_need(p, end, 1 + 1, bad);
  64         mdsmap_v = ceph_decode_8(p);
  65         mdsmap_cv = ceph_decode_8(p);
  66         if (mdsmap_v >= 4) {
  67                u32 mdsmap_len;
  68                ceph_decode_32_safe(p, end, mdsmap_len, bad);
  69                if (end < *p + mdsmap_len)
  70                        goto bad;
  71                end = *p + mdsmap_len;
  72         }
  73
  74         ceph_decode_need(p, end, 8*sizeof(u32) + sizeof(u64), bad);
  75         m->m_epoch = ceph_decode_32(p);
  76         m->m_client_epoch = ceph_decode_32(p);
  77         m->m_last_failure = ceph_decode_32(p);
  78         m->m_root = ceph_decode_32(p);
  79         m->m_session_timeout = ceph_decode_32(p);
  80         m->m_session_autoclose = ceph_decode_32(p);
  81         m->m_max_file_size = ceph_decode_64(p);
  82         m->m_max_mds = ceph_decode_32(p);
  83
  84         m->m_info = kcalloc(m->m_max_mds, sizeof(*m->m_info), GFP_NOFS);
  85         if (m->m_info == NULL)
  86                 goto badmem;
  87
  88         /* pick out active nodes from mds_info (state > 0) */
  89         n = ceph_decode_32(p);
  90         for (i = 0; i < n; i++) {
  91                 u64 global_id;
  92                 u32 namelen;
  93                 s32 mds, inc, state;
  94                 u64 state_seq;
  95                 u8 info_v;
  96                 void *info_end = NULL;
  97                 struct ceph_entity_addr addr;
  98                 u32 num_export_targets;
  99                 void *pexport_targets = NULL;
 100                 struct ceph_timespec laggy_since;
 101                 struct ceph_mds_info *info;
 102
 103                 ceph_decode_need(p, end, sizeof(u64) + 1, bad);
 104                 global_id = ceph_decode_64(p);
 105                 info_v= ceph_decode_8(p);
 106                 if (info_v >= 4) {
 107                         u32 info_len;
 108                         u8 info_cv;
 109                         ceph_decode_need(p, end, 1 + sizeof(u32), bad);
 110                         info_cv = ceph_decode_8(p);
 111                         info_len = ceph_decode_32(p);
 112                         info_end = *p + info_len;
 113                         if (info_end > end)
 114                                 goto bad;
 115                 }
 116
 117                 ceph_decode_need(p, end, sizeof(u64) + sizeof(u32), bad);
 118                 *p += sizeof(u64);
 119                 namelen = ceph_decode_32(p);  /* skip mds name */
 120                 *p += namelen;
 121
 122                 ceph_decode_need(p, end,
 123                                  4*sizeof(u32) + sizeof(u64) +
 124                                  sizeof(addr) + sizeof(struct ceph_timespec),
 125                                  bad);
 126                 mds = ceph_decode_32(p);
 127                 inc = ceph_decode_32(p);
 128                 state = ceph_decode_32(p);
 129                 state_seq = ceph_decode_64(p);
 130                 ceph_decode_copy(p, &addr, sizeof(addr));
 131                 ceph_decode_addr(&addr);
 132                 ceph_decode_copy(p, &laggy_since, sizeof(laggy_since));
 133                 *p += sizeof(u32);
 134                 ceph_decode_32_safe(p, end, namelen, bad);
 135                 *p += namelen;
 136                 if (info_v >= 2) {
 137                         ceph_decode_32_safe(p, end, num_export_targets, bad);
 138                         pexport_targets = *p;
 139                         *p += num_export_targets * sizeof(u32);
 140                 } else {
 141                         num_export_targets = 0;
 142                 }
 143
 144                 if (info_end && *p != info_end) {
 145                         if (*p > info_end)
 146                                 goto bad;
 147                         *p = info_end;
 148                 }
 149
 150                 dout("mdsmap_decode %d/%d %lld mds%d.%d %s %s\n",
 151                      i+1, n, global_id, mds, inc,
 152                      ceph_pr_addr(&addr.in_addr),
 153                      ceph_mds_state_name(state));
 154
 155                 if (mds < 0 || mds >= m->m_max_mds || state <= 0)
 156                         continue;
 157
 158                 info = &m->m_info[mds];
 159                 info->global_id = global_id;
 160                 info->state = state;
 161                 info->addr = addr;
 162                 info->laggy = (laggy_since.tv_sec != 0 ||
 163                                laggy_since.tv_nsec != 0);
 164                 info->num_export_targets = num_export_targets;
 165                 if (num_export_targets) {
 166                         info->export_targets = kcalloc(num_export_targets,
 167                                                        sizeof(u32), GFP_NOFS);
 168                         if (info->export_targets == NULL)
 169                                 goto badmem;
 170                         for (j = 0; j < num_export_targets; j++)
 171                                 info->export_targets[j] =
 172                                        ceph_decode_32(&pexport_targets);
 173                 } else {
 174                         info->export_targets = NULL;
 175                 }
 176         }
 177
 178         /* pg_pools */
 179         ceph_decode_32_safe(p, end, n, bad);
 180         m->m_num_data_pg_pools = n;
 181         m->m_data_pg_pools = kcalloc(n, sizeof(u64), GFP_NOFS);
 182         if (!m->m_data_pg_pools)
 183                 goto badmem;
 184         ceph_decode_need(p, end, sizeof(u64)*(n+1), bad);
 185         for (i = 0; i < n; i++)
 186                 m->m_data_pg_pools[i] = ceph_decode_64(p);
 187         m->m_cas_pg_pool = ceph_decode_64(p);
 188
 189         /* ok, we don't care about the rest. */
 190         *p = end;
 191         dout("mdsmap_decode success epoch %u\n", m->m_epoch);
 192         return m;
 193
 194 badmem:
 195         err = -ENOMEM;
 196 bad:
 197         pr_err("corrupt mdsmap\n");
 198         print_hex_dump(KERN_DEBUG, "mdsmap: ",
 199                        DUMP_PREFIX_OFFSET, 16, 1,
 200                        start, end - start, true);
 201         ceph_mdsmap_destroy(m);
 202         return ERR_PTR(err);
 203 }
 204
 205 void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
 206 {
 207         int i;
 208
 209         for (i = 0; i < m->m_max_mds; i++)
 210                 kfree(m->m_info[i].export_targets);
 211         kfree(m->m_info);
 212         kfree(m->m_data_pg_pools);
 213         kfree(m);
 214 }