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  */
ceph_mdsmap_get_random_mds(struct ceph_mdsmap * m)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  */
ceph_mdsmap_decode(void ** p,void * end)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 		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,
121 		     ceph_pr_addr(&addr.in_addr),
122 		     ceph_mds_state_name(state));
123 		if (mds >= 0 && mds < m->m_max_mds && state > 0) {
124 			m->m_info[mds].global_id = global_id;
125 			m->m_info[mds].state = state;
126 			m->m_info[mds].addr = addr;
127 			m->m_info[mds].laggy =
128 				(laggy_since.tv_sec != 0 ||
129 				 laggy_since.tv_nsec != 0);
130 			m->m_info[mds].num_export_targets = num_export_targets;
131 			if (num_export_targets) {
132 				m->m_info[mds].export_targets =
133 					kcalloc(num_export_targets, sizeof(u32),
134 						GFP_NOFS);
135 				for (j = 0; j < num_export_targets; j++)
136 					m->m_info[mds].export_targets[j] =
137 					       ceph_decode_32(&pexport_targets);
138 			} else {
139 				m->m_info[mds].export_targets = NULL;
140 			}
141 		}
142 	}
143 
144 	/* pg_pools */
145 	ceph_decode_32_safe(p, end, n, bad);
146 	m->m_num_data_pg_pools = n;
147 	m->m_data_pg_pools = kcalloc(n, sizeof(u32), GFP_NOFS);
148 	if (!m->m_data_pg_pools)
149 		goto badmem;
150 	ceph_decode_need(p, end, sizeof(u32)*(n+1), bad);
151 	for (i = 0; i < n; i++)
152 		m->m_data_pg_pools[i] = ceph_decode_32(p);
153 	m->m_cas_pg_pool = ceph_decode_32(p);
154 
155 	/* ok, we don't care about the rest. */
156 	dout("mdsmap_decode success epoch %u\n", m->m_epoch);
157 	return m;
158 
159 badmem:
160 	err = -ENOMEM;
161 bad:
162 	pr_err("corrupt mdsmap\n");
163 	print_hex_dump(KERN_DEBUG, "mdsmap: ",
164 		       DUMP_PREFIX_OFFSET, 16, 1,
165 		       start, end - start, true);
166 	ceph_mdsmap_destroy(m);
167 	return ERR_PTR(-EINVAL);
168 }
169 
ceph_mdsmap_destroy(struct ceph_mdsmap * m)170 void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
171 {
172 	int i;
173 
174 	for (i = 0; i < m->m_max_mds; i++)
175 		kfree(m->m_info[i].export_targets);
176 	kfree(m->m_info);
177 	kfree(m->m_data_pg_pools);
178 	kfree(m);
179 }
180