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 */
19int 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 */
49struct 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		struct ceph_timespec laggy_since;
89
90		ceph_decode_need(p, end, sizeof(u64)*2 + 1 + sizeof(u32), bad);
91		global_id = ceph_decode_64(p);
92		infoversion = ceph_decode_8(p);
93		*p += sizeof(u64);
94		namelen = ceph_decode_32(p);  /* skip mds name */
95		*p += namelen;
96
97		ceph_decode_need(p, end,
98				 4*sizeof(u32) + sizeof(u64) +
99				 sizeof(addr) + sizeof(struct ceph_timespec),
100				 bad);
101		mds = ceph_decode_32(p);
102		inc = ceph_decode_32(p);
103		state = ceph_decode_32(p);
104		state_seq = ceph_decode_64(p);
105		ceph_decode_copy(p, &addr, sizeof(addr));
106		ceph_decode_addr(&addr);
107		ceph_decode_copy(p, &laggy_since, sizeof(laggy_since));
108		*p += sizeof(u32);
109		ceph_decode_32_safe(p, end, namelen, bad);
110		*p += namelen;
111		if (infoversion >= 2) {
112			ceph_decode_32_safe(p, end, num_export_targets, bad);
113			pexport_targets = *p;
114			*p += num_export_targets * sizeof(u32);
115		} else {
116			num_export_targets = 0;
117		}
118
119		dout("mdsmap_decode %d/%d %lld mds%d.%d %s %s\n",
120		     i+1, n, global_id, mds, inc, pr_addr(&addr.in_addr),
121		     ceph_mds_state_name(state));
122		if (mds >= 0 && mds < m->m_max_mds && state > 0) {
123			m->m_info[mds].global_id = global_id;
124			m->m_info[mds].state = state;
125			m->m_info[mds].addr = addr;
126			m->m_info[mds].laggy =
127				(laggy_since.tv_sec != 0 ||
128				 laggy_since.tv_nsec != 0);
129			m->m_info[mds].num_export_targets = num_export_targets;
130			if (num_export_targets) {
131				m->m_info[mds].export_targets =
132					kcalloc(num_export_targets, sizeof(u32),
133						GFP_NOFS);
134				for (j = 0; j < num_export_targets; j++)
135					m->m_info[mds].export_targets[j] =
136					       ceph_decode_32(&pexport_targets);
137			} else {
138				m->m_info[mds].export_targets = NULL;
139			}
140		}
141	}
142
143	/* pg_pools */
144	ceph_decode_32_safe(p, end, n, bad);
145	m->m_num_data_pg_pools = n;
146	m->m_data_pg_pools = kcalloc(n, sizeof(u32), GFP_NOFS);
147	if (!m->m_data_pg_pools)
148		goto badmem;
149	ceph_decode_need(p, end, sizeof(u32)*(n+1), bad);
150	for (i = 0; i < n; i++)
151		m->m_data_pg_pools[i] = ceph_decode_32(p);
152	m->m_cas_pg_pool = ceph_decode_32(p);
153
154	/* ok, we don't care about the rest. */
155	dout("mdsmap_decode success epoch %u\n", m->m_epoch);
156	return m;
157
158badmem:
159	err = -ENOMEM;
160bad:
161	pr_err("corrupt mdsmap\n");
162	print_hex_dump(KERN_DEBUG, "mdsmap: ",
163		       DUMP_PREFIX_OFFSET, 16, 1,
164		       start, end - start, true);
165	ceph_mdsmap_destroy(m);
166	return ERR_PTR(-EINVAL);
167}
168
169void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
170{
171	int i;
172
173	for (i = 0; i < m->m_max_mds; i++)
174		kfree(m->m_info[i].export_targets);
175	kfree(m->m_info);
176	kfree(m->m_data_pg_pools);
177	kfree(m);
178}
179