ceph: fix mdsmap decoding when multiple mds's are present
[linux-2.6.git] / 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                 ceph_decode_copy(p, &addr, sizeof(addr));
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                                  4*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                 *p += sizeof(addr);
102                 *p += sizeof(struct ceph_timespec);
103                 *p += sizeof(u32);
104                 ceph_decode_32_safe(p, end, namelen, bad);
105                 *p += namelen;
106                 if (infoversion >= 2) {
107                         ceph_decode_32_safe(p, end, num_export_targets, bad);
108                         pexport_targets = *p;
109                         *p += 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 }