fs/ceph/mdsmap.c

   1 #include "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 "mdsmap.h"
  10 #include "messenger.h"
  11 #include "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         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  */
  49 struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
  50 {
  51         struct ceph_mdsmap *m;
  52         int i, j, n;
  53         int err = -EINVAL;
  54         u16 version;
  55
  56         m = kzalloc(sizeof(*m), GFP_NOFS);
  57         if (m == NULL)
  58                 return ERR_PTR(-ENOMEM);
  59
  60         ceph_decode_16_safe(p, end, version, bad);
  61
  62         ceph_decode_need(p, end, 8*sizeof(u32) + sizeof(u64), bad);
  63         ceph_decode_32(p, m->m_epoch);
  64         ceph_decode_32(p, m->m_client_epoch);
  65         ceph_decode_32(p, m->m_last_failure);
  66         ceph_decode_32(p, m->m_root);
  67         ceph_decode_32(p, m->m_session_timeout);
  68         ceph_decode_32(p, m->m_session_autoclose);
  69         ceph_decode_64(p, m->m_max_file_size);
  70         ceph_decode_32(p, m->m_max_mds);
  71
  72         m->m_info = kcalloc(m->m_max_mds, sizeof(*m->m_info), GFP_NOFS);
  73         if (m->m_info == NULL)
  74                 goto badmem;
  75
  76         /* pick out active nodes from mds_info (state > 0) */
  77         ceph_decode_32(p, n);
  78         for (i = 0; i < n; i++) {
  79                 u32 namelen;
  80                 s32 mds, inc, state;
  81                 u64 state_seq;
  82                 u8 infoversion;
  83                 struct ceph_entity_addr addr;
  84                 u32 num_export_targets;
  85                 void *pexport_targets = NULL;
  86
  87                 ceph_decode_need(p, end, sizeof(addr) + 1 + sizeof(u32), bad);
  88                 *p += sizeof(addr);          /* skip addr key */
  89                 ceph_decode_8(p, infoversion);
  90                 ceph_decode_32(p, namelen);  /* skip mds name */
  91                 *p += namelen;
  92
  93                 ceph_decode_need(p, end,
  94                                  5*sizeof(u32) + sizeof(u64) +
  95                                  sizeof(addr) + sizeof(struct ceph_timespec),
  96                                  bad);
  97                 ceph_decode_32(p, mds);
  98                 ceph_decode_32(p, inc);
  99                 ceph_decode_32(p, state);
 100                 ceph_decode_64(p, state_seq);
 101                 ceph_decode_copy(p, &addr, sizeof(addr));
 102                 *p += sizeof(struct ceph_timespec);
 103                 *p += sizeof(u32);
 104                 ceph_decode_32_safe(p, end, namelen, bad);
 105                 *p += sizeof(namelen);
 106                 if (infoversion >= 2) {
 107                         ceph_decode_32_safe(p, end, num_export_targets, bad);
 108                         pexport_targets = *p;
 109                         *p += sizeof(num_export_targets * sizeof(u32));
 110                 } else {
 111                         num_export_targets = 0;
 112                 }
 113
 114                 dout("mdsmap_decode %d/%d mds%d.%d %s %s\n",
 115                      i+1, n, mds, inc, pr_addr(&addr.in_addr),
 116                      ceph_mds_state_name(state));
 117                 if (mds >= 0 && mds < m->m_max_mds && state > 0) {
 118                         m->m_info[mds].state = state;
 119                         m->m_info[mds].addr = addr;
 120                         m->m_info[mds].num_export_targets = num_export_targets;
 121                         if (num_export_targets) {
 122                                 m->m_info[mds].export_targets =
 123                                         kcalloc(num_export_targets, sizeof(u32),
 124                                                 GFP_NOFS);
 125                                 for (j = 0; j < num_export_targets; j++)
 126                                         ceph_decode_32(&pexport_targets,
 127                                               m->m_info[mds].export_targets[j]);
 128                         } else {
 129                                 m->m_info[mds].export_targets = NULL;
 130                         }
 131                 }
 132         }
 133
 134         /* pg_pools */
 135         ceph_decode_32_safe(p, end, n, bad);
 136         m->m_num_data_pg_pools = n;
 137         m->m_data_pg_pools = kcalloc(n, sizeof(u32), GFP_NOFS);
 138         if (!m->m_data_pg_pools)
 139                 goto badmem;
 140         ceph_decode_need(p, end, sizeof(u32)*(n+1), bad);
 141         for (i = 0; i < n; i++)
 142                 ceph_decode_32(p, m->m_data_pg_pools[i]);
 143         ceph_decode_32(p, m->m_cas_pg_pool);
 144
 145         /* ok, we don't care about the rest. */
 146         dout("mdsmap_decode success epoch %u\n", m->m_epoch);
 147         return m;
 148
 149 badmem:
 150         err = -ENOMEM;
 151 bad:
 152         pr_err("corrupt mdsmap\n");
 153         ceph_mdsmap_destroy(m);
 154         return ERR_PTR(-EINVAL);
 155 }
 156
 157 void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
 158 {
 159         int i;
 160
 161         for (i = 0; i < m->m_max_mds; i++)
 162                 kfree(m->m_info[i].export_targets);
 163         kfree(m->m_info);
 164         kfree(m->m_data_pg_pools);
 165         kfree(m);
 166 }