xref: /kernel/linux/linux-6.6/fs/ceph/mdsmap.c (revision 62306a36)
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/ceph/ceph_debug.h>
3
4#include <linux/bug.h>
5#include <linux/err.h>
6#include <linux/random.h>
7#include <linux/slab.h>
8#include <linux/types.h>
9
10#include <linux/ceph/mdsmap.h>
11#include <linux/ceph/messenger.h>
12#include <linux/ceph/decode.h>
13
14#include "super.h"
15
16#define CEPH_MDS_IS_READY(i, ignore_laggy) \
17	(m->m_info[i].state > 0 && ignore_laggy ? true : !m->m_info[i].laggy)
18
19static int __mdsmap_get_random_mds(struct ceph_mdsmap *m, bool ignore_laggy)
20{
21	int n = 0;
22	int i, j;
23
24	/* count */
25	for (i = 0; i < m->possible_max_rank; i++)
26		if (CEPH_MDS_IS_READY(i, ignore_laggy))
27			n++;
28	if (n == 0)
29		return -1;
30
31	/* pick */
32	n = get_random_u32_below(n);
33	for (j = 0, i = 0; i < m->possible_max_rank; i++) {
34		if (CEPH_MDS_IS_READY(i, ignore_laggy))
35			j++;
36		if (j > n)
37			break;
38	}
39
40	return i;
41}
42
43/*
44 * choose a random mds that is "up" (i.e. has a state > 0), or -1.
45 */
46int ceph_mdsmap_get_random_mds(struct ceph_mdsmap *m)
47{
48	int mds;
49
50	mds = __mdsmap_get_random_mds(m, false);
51	if (mds == m->possible_max_rank || mds == -1)
52		mds = __mdsmap_get_random_mds(m, true);
53
54	return mds == m->possible_max_rank ? -1 : mds;
55}
56
57#define __decode_and_drop_type(p, end, type, bad)		\
58	do {							\
59		if (*p + sizeof(type) > end)			\
60			goto bad;				\
61		*p += sizeof(type);				\
62	} while (0)
63
64#define __decode_and_drop_set(p, end, type, bad)		\
65	do {							\
66		u32 n;						\
67		size_t need;					\
68		ceph_decode_32_safe(p, end, n, bad);		\
69		need = sizeof(type) * n;			\
70		ceph_decode_need(p, end, need, bad);		\
71		*p += need;					\
72	} while (0)
73
74#define __decode_and_drop_map(p, end, ktype, vtype, bad)	\
75	do {							\
76		u32 n;						\
77		size_t need;					\
78		ceph_decode_32_safe(p, end, n, bad);		\
79		need = (sizeof(ktype) + sizeof(vtype)) * n;	\
80		ceph_decode_need(p, end, need, bad);		\
81		*p += need;					\
82	} while (0)
83
84
85static int __decode_and_drop_compat_set(void **p, void* end)
86{
87	int i;
88	/* compat, ro_compat, incompat*/
89	for (i = 0; i < 3; i++) {
90		u32 n;
91		ceph_decode_need(p, end, sizeof(u64) + sizeof(u32), bad);
92		/* mask */
93		*p += sizeof(u64);
94		/* names (map<u64, string>) */
95		n = ceph_decode_32(p);
96		while (n-- > 0) {
97			u32 len;
98			ceph_decode_need(p, end, sizeof(u64) + sizeof(u32),
99					 bad);
100			*p += sizeof(u64);
101			len = ceph_decode_32(p);
102			ceph_decode_need(p, end, len, bad);
103			*p += len;
104		}
105	}
106	return 0;
107bad:
108	return -1;
109}
110
111/*
112 * Decode an MDS map
113 *
114 * Ignore any fields we don't care about (there are quite a few of
115 * them).
116 */
117struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end, bool msgr2)
118{
119	struct ceph_mdsmap *m;
120	const void *start = *p;
121	int i, j, n;
122	int err;
123	u8 mdsmap_v;
124	u16 mdsmap_ev;
125	u32 target;
126
127	m = kzalloc(sizeof(*m), GFP_NOFS);
128	if (!m)
129		return ERR_PTR(-ENOMEM);
130
131	ceph_decode_need(p, end, 1 + 1, bad);
132	mdsmap_v = ceph_decode_8(p);
133	*p += sizeof(u8);			/* mdsmap_cv */
134	if (mdsmap_v >= 4) {
135	       u32 mdsmap_len;
136	       ceph_decode_32_safe(p, end, mdsmap_len, bad);
137	       if (end < *p + mdsmap_len)
138		       goto bad;
139	       end = *p + mdsmap_len;
140	}
141
142	ceph_decode_need(p, end, 8*sizeof(u32) + sizeof(u64), bad);
143	m->m_epoch = ceph_decode_32(p);
144	m->m_client_epoch = ceph_decode_32(p);
145	m->m_last_failure = ceph_decode_32(p);
146	m->m_root = ceph_decode_32(p);
147	m->m_session_timeout = ceph_decode_32(p);
148	m->m_session_autoclose = ceph_decode_32(p);
149	m->m_max_file_size = ceph_decode_64(p);
150	m->m_max_mds = ceph_decode_32(p);
151
152	/*
153	 * pick out the active nodes as the m_num_active_mds, the
154	 * m_num_active_mds maybe larger than m_max_mds when decreasing
155	 * the max_mds in cluster side, in other case it should less
156	 * than or equal to m_max_mds.
157	 */
158	m->m_num_active_mds = n = ceph_decode_32(p);
159
160	/*
161	 * the possible max rank, it maybe larger than the m_num_active_mds,
162	 * for example if the mds_max == 2 in the cluster, when the MDS(0)
163	 * was laggy and being replaced by a new MDS, we will temporarily
164	 * receive a new mds map with n_num_mds == 1 and the active MDS(1),
165	 * and the mds rank >= m_num_active_mds.
166	 */
167	m->possible_max_rank = max(m->m_num_active_mds, m->m_max_mds);
168
169	m->m_info = kcalloc(m->possible_max_rank, sizeof(*m->m_info), GFP_NOFS);
170	if (!m->m_info)
171		goto nomem;
172
173	/* pick out active nodes from mds_info (state > 0) */
174	for (i = 0; i < n; i++) {
175		u64 global_id;
176		u32 namelen;
177		s32 mds, inc, state;
178		u8 info_v;
179		void *info_end = NULL;
180		struct ceph_entity_addr addr;
181		u32 num_export_targets;
182		void *pexport_targets = NULL;
183		struct ceph_timespec laggy_since;
184		struct ceph_mds_info *info;
185		bool laggy;
186
187		ceph_decode_need(p, end, sizeof(u64) + 1, bad);
188		global_id = ceph_decode_64(p);
189		info_v= ceph_decode_8(p);
190		if (info_v >= 4) {
191			u32 info_len;
192			ceph_decode_need(p, end, 1 + sizeof(u32), bad);
193			*p += sizeof(u8);	/* info_cv */
194			info_len = ceph_decode_32(p);
195			info_end = *p + info_len;
196			if (info_end > end)
197				goto bad;
198		}
199
200		ceph_decode_need(p, end, sizeof(u64) + sizeof(u32), bad);
201		*p += sizeof(u64);
202		namelen = ceph_decode_32(p);  /* skip mds name */
203		*p += namelen;
204
205		ceph_decode_32_safe(p, end, mds, bad);
206		ceph_decode_32_safe(p, end, inc, bad);
207		ceph_decode_32_safe(p, end, state, bad);
208		*p += sizeof(u64);		/* state_seq */
209		if (info_v >= 8)
210			err = ceph_decode_entity_addrvec(p, end, msgr2, &addr);
211		else
212			err = ceph_decode_entity_addr(p, end, &addr);
213		if (err)
214			goto corrupt;
215
216		ceph_decode_copy_safe(p, end, &laggy_since, sizeof(laggy_since),
217				      bad);
218		laggy = laggy_since.tv_sec != 0 || laggy_since.tv_nsec != 0;
219		*p += sizeof(u32);
220		ceph_decode_32_safe(p, end, namelen, bad);
221		*p += namelen;
222		if (info_v >= 2) {
223			ceph_decode_32_safe(p, end, num_export_targets, bad);
224			pexport_targets = *p;
225			*p += num_export_targets * sizeof(u32);
226		} else {
227			num_export_targets = 0;
228		}
229
230		if (info_end && *p != info_end) {
231			if (*p > info_end)
232				goto bad;
233			*p = info_end;
234		}
235
236		dout("mdsmap_decode %d/%d %lld mds%d.%d %s %s%s\n",
237		     i+1, n, global_id, mds, inc,
238		     ceph_pr_addr(&addr),
239		     ceph_mds_state_name(state),
240		     laggy ? "(laggy)" : "");
241
242		if (mds < 0 || mds >= m->possible_max_rank) {
243			pr_warn("mdsmap_decode got incorrect mds(%d)\n", mds);
244			continue;
245		}
246
247		if (state <= 0) {
248			dout("mdsmap_decode got incorrect state(%s)\n",
249			     ceph_mds_state_name(state));
250			continue;
251		}
252
253		info = &m->m_info[mds];
254		info->global_id = global_id;
255		info->state = state;
256		info->addr = addr;
257		info->laggy = laggy;
258		info->num_export_targets = num_export_targets;
259		if (num_export_targets) {
260			info->export_targets = kcalloc(num_export_targets,
261						       sizeof(u32), GFP_NOFS);
262			if (!info->export_targets)
263				goto nomem;
264			for (j = 0; j < num_export_targets; j++) {
265				target = ceph_decode_32(&pexport_targets);
266				info->export_targets[j] = target;
267			}
268		} else {
269			info->export_targets = NULL;
270		}
271	}
272
273	/* pg_pools */
274	ceph_decode_32_safe(p, end, n, bad);
275	m->m_num_data_pg_pools = n;
276	m->m_data_pg_pools = kcalloc(n, sizeof(u64), GFP_NOFS);
277	if (!m->m_data_pg_pools)
278		goto nomem;
279	ceph_decode_need(p, end, sizeof(u64)*(n+1), bad);
280	for (i = 0; i < n; i++)
281		m->m_data_pg_pools[i] = ceph_decode_64(p);
282	m->m_cas_pg_pool = ceph_decode_64(p);
283	m->m_enabled = m->m_epoch > 1;
284
285	mdsmap_ev = 1;
286	if (mdsmap_v >= 2) {
287		ceph_decode_16_safe(p, end, mdsmap_ev, bad_ext);
288	}
289	if (mdsmap_ev >= 3) {
290		if (__decode_and_drop_compat_set(p, end) < 0)
291			goto bad_ext;
292	}
293	/* metadata_pool */
294	if (mdsmap_ev < 5) {
295		__decode_and_drop_type(p, end, u32, bad_ext);
296	} else {
297		__decode_and_drop_type(p, end, u64, bad_ext);
298	}
299
300	/* created + modified + tableserver */
301	__decode_and_drop_type(p, end, struct ceph_timespec, bad_ext);
302	__decode_and_drop_type(p, end, struct ceph_timespec, bad_ext);
303	__decode_and_drop_type(p, end, u32, bad_ext);
304
305	/* in */
306	{
307		int num_laggy = 0;
308		ceph_decode_32_safe(p, end, n, bad_ext);
309		ceph_decode_need(p, end, sizeof(u32) * n, bad_ext);
310
311		for (i = 0; i < n; i++) {
312			s32 mds = ceph_decode_32(p);
313			if (mds >= 0 && mds < m->possible_max_rank) {
314				if (m->m_info[mds].laggy)
315					num_laggy++;
316			}
317		}
318		m->m_num_laggy = num_laggy;
319
320		if (n > m->possible_max_rank) {
321			void *new_m_info = krealloc(m->m_info,
322						    n * sizeof(*m->m_info),
323						    GFP_NOFS | __GFP_ZERO);
324			if (!new_m_info)
325				goto nomem;
326			m->m_info = new_m_info;
327		}
328		m->possible_max_rank = n;
329	}
330
331	/* inc */
332	__decode_and_drop_map(p, end, u32, u32, bad_ext);
333	/* up */
334	__decode_and_drop_map(p, end, u32, u64, bad_ext);
335	/* failed */
336	__decode_and_drop_set(p, end, u32, bad_ext);
337	/* stopped */
338	__decode_and_drop_set(p, end, u32, bad_ext);
339
340	if (mdsmap_ev >= 4) {
341		/* last_failure_osd_epoch */
342		__decode_and_drop_type(p, end, u32, bad_ext);
343	}
344	if (mdsmap_ev >= 6) {
345		/* ever_allowed_snaps */
346		__decode_and_drop_type(p, end, u8, bad_ext);
347		/* explicitly_allowed_snaps */
348		__decode_and_drop_type(p, end, u8, bad_ext);
349	}
350	if (mdsmap_ev >= 7) {
351		/* inline_data_enabled */
352		__decode_and_drop_type(p, end, u8, bad_ext);
353	}
354	if (mdsmap_ev >= 8) {
355		/* enabled */
356		ceph_decode_8_safe(p, end, m->m_enabled, bad_ext);
357		/* fs_name */
358		ceph_decode_skip_string(p, end, bad_ext);
359	}
360	/* damaged */
361	if (mdsmap_ev >= 9) {
362		size_t need;
363		ceph_decode_32_safe(p, end, n, bad_ext);
364		need = sizeof(u32) * n;
365		ceph_decode_need(p, end, need, bad_ext);
366		*p += need;
367		m->m_damaged = n > 0;
368	} else {
369		m->m_damaged = false;
370	}
371	if (mdsmap_ev >= 17) {
372		/* balancer */
373		ceph_decode_skip_string(p, end, bad_ext);
374		/* standby_count_wanted */
375		ceph_decode_skip_32(p, end, bad_ext);
376		/* old_max_mds */
377		ceph_decode_skip_32(p, end, bad_ext);
378		/* min_compat_client */
379		ceph_decode_skip_8(p, end, bad_ext);
380		/* required_client_features */
381		ceph_decode_skip_set(p, end, 64, bad_ext);
382		/* bal_rank_mask */
383		ceph_decode_skip_string(p, end, bad_ext);
384	}
385	if (mdsmap_ev >= 18) {
386		ceph_decode_64_safe(p, end, m->m_max_xattr_size, bad_ext);
387	}
388bad_ext:
389	dout("mdsmap_decode m_enabled: %d, m_damaged: %d, m_num_laggy: %d\n",
390	     !!m->m_enabled, !!m->m_damaged, m->m_num_laggy);
391	*p = end;
392	dout("mdsmap_decode success epoch %u\n", m->m_epoch);
393	return m;
394nomem:
395	err = -ENOMEM;
396	goto out_err;
397corrupt:
398	pr_err("corrupt mdsmap\n");
399	print_hex_dump(KERN_DEBUG, "mdsmap: ",
400		       DUMP_PREFIX_OFFSET, 16, 1,
401		       start, end - start, true);
402out_err:
403	ceph_mdsmap_destroy(m);
404	return ERR_PTR(err);
405bad:
406	err = -EINVAL;
407	goto corrupt;
408}
409
410void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
411{
412	int i;
413
414	if (m->m_info) {
415		for (i = 0; i < m->possible_max_rank; i++)
416			kfree(m->m_info[i].export_targets);
417		kfree(m->m_info);
418	}
419	kfree(m->m_data_pg_pools);
420	kfree(m);
421}
422
423bool ceph_mdsmap_is_cluster_available(struct ceph_mdsmap *m)
424{
425	int i, nr_active = 0;
426	if (!m->m_enabled)
427		return false;
428	if (m->m_damaged)
429		return false;
430	if (m->m_num_laggy == m->m_num_active_mds)
431		return false;
432	for (i = 0; i < m->possible_max_rank; i++) {
433		if (m->m_info[i].state == CEPH_MDS_STATE_ACTIVE)
434			nr_active++;
435	}
436	return nr_active > 0;
437}
438