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         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
 169 badmem:
 170         err = -ENOMEM;
 171 bad:
 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
 180 void 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 }