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 */
19int 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 */
51struct 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_warn("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
169badmem:
170	err = -ENOMEM;
171bad:
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
180void 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}
190