linux/fs/ceph/mdsmap.c

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#include "ceph_debug.h"
#include <linux/bug.h>
#include <linux/err.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/types.h>
#include "mdsmap.h"
#include "messenger.h"
#include "decode.h"
#include "super.h"
/*
* choose a random mds that is "up" (i.e. has a state > 0), or -1.
*/
int ceph_mdsmap_get_random_mds(struct ceph_mdsmap *m)
{
int n = 0;
int i;
char r;
/* count */
for (i = 0; i < m->m_max_mds; i++)
if (m->m_info[i].state > 0)
n++;
if (n == 0)
return -1;
/* pick */
get_random_bytes(&r, 1);
n = r % n;
i = 0;
for (i = 0; n > 0; i++, n--)
while (m->m_info[i].state <= 0)
i++;
return i;
}
/*
* Decode an MDS map
*
* Ignore any fields we don't care about (there are quite a few of
* them).
*/
struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
{
struct ceph_mdsmap *m;
int i, j, n;
int err = -EINVAL;
u16 version;
m = kzalloc(sizeof(*m), GFP_NOFS);
if (m == NULL)
return ERR_PTR(-ENOMEM);
ceph_decode_16_safe(p, end, version, bad);
ceph_decode_need(p, end, 8*sizeof(u32) + sizeof(u64), bad);
ceph_decode_32(p, m->m_epoch);
ceph_decode_32(p, m->m_client_epoch);
ceph_decode_32(p, m->m_last_failure);
ceph_decode_32(p, m->m_root);
ceph_decode_32(p, m->m_session_timeout);
ceph_decode_32(p, m->m_session_autoclose);
ceph_decode_64(p, m->m_max_file_size);
ceph_decode_32(p, m->m_max_mds);
m->m_info = kcalloc(m->m_max_mds, sizeof(*m->m_info), GFP_NOFS);
if (m->m_info == NULL)
goto badmem;
/* pick out active nodes from mds_info (state > 0) */
ceph_decode_32(p, n);
for (i = 0; i < n; i++) {
u32 namelen;
s32 mds, inc, state;
u64 state_seq;
u8 infoversion;
struct ceph_entity_addr addr;
u32 num_export_targets;
void *pexport_targets = NULL;
ceph_decode_need(p, end, sizeof(addr) + 1 + sizeof(u32), bad);
*p += sizeof(addr); /* skip addr key */
ceph_decode_8(p, infoversion);
ceph_decode_32(p, namelen); /* skip mds name */
*p += namelen;
ceph_decode_need(p, end,
5*sizeof(u32) + sizeof(u64) +
sizeof(addr) + sizeof(struct ceph_timespec),
bad);
ceph_decode_32(p, mds);
ceph_decode_32(p, inc);
ceph_decode_32(p, state);
ceph_decode_64(p, state_seq);
ceph_decode_copy(p, &addr, sizeof(addr));
*p += sizeof(struct ceph_timespec);
*p += sizeof(u32);
ceph_decode_32_safe(p, end, namelen, bad);
*p += sizeof(namelen);
if (infoversion >= 2) {
ceph_decode_32_safe(p, end, num_export_targets, bad);
pexport_targets = *p;
*p += sizeof(num_export_targets * sizeof(u32));
} else {
num_export_targets = 0;
}
dout("mdsmap_decode %d/%d mds%d.%d %s %s\n",
i+1, n, mds, inc, pr_addr(&addr.in_addr),
ceph_mds_state_name(state));
if (mds >= 0 && mds < m->m_max_mds && state > 0) {
m->m_info[mds].state = state;
m->m_info[mds].addr = addr;
m->m_info[mds].num_export_targets = num_export_targets;
if (num_export_targets) {
m->m_info[mds].export_targets =
kcalloc(num_export_targets, sizeof(u32),
GFP_NOFS);
for (j = 0; j < num_export_targets; j++)
ceph_decode_32(&pexport_targets,
m->m_info[mds].export_targets[j]);
} else {
m->m_info[mds].export_targets = NULL;
}
}
}
/* pg_pools */
ceph_decode_32_safe(p, end, n, bad);
m->m_num_data_pg_pools = n;
m->m_data_pg_pools = kcalloc(n, sizeof(u32), GFP_NOFS);
if (!m->m_data_pg_pools)
goto badmem;
ceph_decode_need(p, end, sizeof(u32)*(n+1), bad);
for (i = 0; i < n; i++)
ceph_decode_32(p, m->m_data_pg_pools[i]);
ceph_decode_32(p, m->m_cas_pg_pool);
/* ok, we don't care about the rest. */
dout("mdsmap_decode success epoch %u\n", m->m_epoch);
return m;
badmem:
err = -ENOMEM;
bad:
pr_err("corrupt mdsmap\n");
ceph_mdsmap_destroy(m);
return ERR_PTR(-EINVAL);
}
void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
{
int i;
for (i = 0; i < m->m_max_mds; i++)
kfree(m->m_info[i].export_targets);
kfree(m->m_info);
kfree(m->m_data_pg_pools);
kfree(m);
}