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         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
  89                 ceph_decode_need(p, end, sizeof(u64)*2 + 1 + sizeof(u32), bad);
  90                 global_id = ceph_decode_64(p);
  91                 infoversion = ceph_decode_8(p);
  92                 *p += sizeof(u64);
  93                 namelen = ceph_decode_32(p);  /* skip mds name */
  94                 *p += namelen;
  95
  96                 ceph_decode_need(p, end,
  97                                  4*sizeof(u32) + sizeof(u64) +
  98                                  sizeof(addr) + sizeof(struct ceph_timespec),
  99                                  bad);
 100                 mds = ceph_decode_32(p);
 101                 inc = ceph_decode_32(p);
 102                 state = ceph_decode_32(p);
 103                 state_seq = ceph_decode_64(p);
 104                 ceph_decode_copy(p, &addr, sizeof(addr));
 105                 ceph_decode_addr(&addr);
 106                 *p += sizeof(struct ceph_timespec);
 107                 *p += sizeof(u32);
 108                 ceph_decode_32_safe(p, end, namelen, bad);
 109                 *p += namelen;
 110                 if (infoversion >= 2) {
 111                         ceph_decode_32_safe(p, end, num_export_targets, bad);
 112                         pexport_targets = *p;
 113                         *p += num_export_targets * sizeof(u32);
 114                 } else {
 115                         num_export_targets = 0;
 116                 }
 117
 118                 dout("mdsmap_decode %d/%d %lld mds%d.%d %s %s\n",
 119                      i+1, n, global_id, mds, inc, pr_addr(&addr.in_addr),
 120                      ceph_mds_state_name(state));
 121                 if (mds >= 0 && mds < m->m_max_mds && state > 0) {
 122                         m->m_info[mds].global_id = global_id;
 123                         m->m_info[mds].state = state;
 124                         m->m_info[mds].addr = addr;
 125                         m->m_info[mds].num_export_targets = num_export_targets;
 126                         if (num_export_targets) {
 127                                 m->m_info[mds].export_targets =
 128                                         kcalloc(num_export_targets, sizeof(u32),
 129                                                 GFP_NOFS);
 130                                 for (j = 0; j < num_export_targets; j++)
 131                                         m->m_info[mds].export_targets[j] =
 132                                                ceph_decode_32(&pexport_targets);
 133                         } else {
 134                                 m->m_info[mds].export_targets = NULL;
 135                         }
 136                 }
 137         }
 138
 139         /* pg_pools */
 140         ceph_decode_32_safe(p, end, n, bad);
 141         m->m_num_data_pg_pools = n;
 142         m->m_data_pg_pools = kcalloc(n, sizeof(u32), GFP_NOFS);
 143         if (!m->m_data_pg_pools)
 144                 goto badmem;
 145         ceph_decode_need(p, end, sizeof(u32)*(n+1), bad);
 146         for (i = 0; i < n; i++)
 147                 m->m_data_pg_pools[i] = ceph_decode_32(p);
 148         m->m_cas_pg_pool = ceph_decode_32(p);
 149
 150         /* ok, we don't care about the rest. */
 151         dout("mdsmap_decode success epoch %u\n", m->m_epoch);
 152         return m;
 153
 154 badmem:
 155         err = -ENOMEM;
 156 bad:
 157         pr_err("corrupt mdsmap\n");
 158         print_hex_dump(KERN_DEBUG, "mdsmap: ",
 159                        DUMP_PREFIX_OFFSET, 16, 1,
 160                        start, end - start, true);
 161         ceph_mdsmap_destroy(m);
 162         return ERR_PTR(-EINVAL);
 163 }
 164
 165 void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
 166 {
 167         int i;
 168
 169         for (i = 0; i < m->m_max_mds; i++)
 170                 kfree(m->m_info[i].export_targets);
 171         kfree(m->m_info);
 172         kfree(m->m_data_pg_pools);
 173         kfree(m);
 174 }