#include <linux/ceph/ceph_debug.h>

  
  #include <linux/bug.h>
  #include <linux/err.h>
  #include <linux/random.h>
  #include <linux/slab.h>
  #include <linux/types.h>

  #include <linux/ceph/mdsmap.h>
  #include <linux/ceph/messenger.h>
  #include <linux/ceph/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;

  	const void *start = *p;

  	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);

  	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_32(p);
  	m->m_max_file_size = ceph_decode_64(p);
  	m->m_max_mds = ceph_decode_32(p);

  
  	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) */

  	n = ceph_decode_32(p);

  	for (i = 0; i < n; i++) {

  		u64 global_id;

  		u32 namelen;
  		s32 mds, inc, state;
  		u64 state_seq;
  		u8 infoversion;
  		struct ceph_entity_addr addr;
  		u32 num_export_targets;
  		void *pexport_targets = NULL;

  		struct ceph_timespec laggy_since;

  		ceph_decode_need(p, end, sizeof(u64)*2 + 1 + sizeof(u32), bad);
  		global_id = ceph_decode_64(p);

  		infoversion = ceph_decode_8(p);

  		*p += sizeof(u64);

  		namelen = ceph_decode_32(p);  /* skip mds name */

  		*p += namelen;
  
  		ceph_decode_need(p, end,

  				 4*sizeof(u32) + sizeof(u64) +

  				 sizeof(addr) + sizeof(struct ceph_timespec),
  				 bad);

  		mds = ceph_decode_32(p);
  		inc = ceph_decode_32(p);
  		state = ceph_decode_32(p);
  		state_seq = ceph_decode_64(p);

  		ceph_decode_copy(p, &addr, sizeof(addr));
  		ceph_decode_addr(&addr);

  		ceph_decode_copy(p, &laggy_since, sizeof(laggy_since));

  		*p += sizeof(u32);
  		ceph_decode_32_safe(p, end, namelen, bad);

  		*p += namelen;

  		if (infoversion >= 2) {
  			ceph_decode_32_safe(p, end, num_export_targets, bad);
  			pexport_targets = *p;

  			*p += num_export_targets * sizeof(u32);

  		} else {
  			num_export_targets = 0;
  		}

  		dout("mdsmap_decode %d/%d %lld mds%d.%d %s %s
  ",

  		     i+1, n, global_id, mds, inc,
  		     ceph_pr_addr(&addr.in_addr),

  		     ceph_mds_state_name(state));
  		if (mds >= 0 && mds < m->m_max_mds && state > 0) {

  			m->m_info[mds].global_id = global_id;

  			m->m_info[mds].state = state;
  			m->m_info[mds].addr = addr;

  			m->m_info[mds].laggy =
  				(laggy_since.tv_sec != 0 ||
  				 laggy_since.tv_nsec != 0);

  			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++)

  					m->m_info[mds].export_targets[j] =
  					       ceph_decode_32(&pexport_targets);

  			} 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++)

  		m->m_data_pg_pools[i] = ceph_decode_32(p);
  	m->m_cas_pg_pool = ceph_decode_32(p);

  
  	/* ok, we don't care about the rest. */
  	dout("mdsmap_decode success epoch %u
  ", m->m_epoch);
  	return m;
  
  badmem:
  	err = -ENOMEM;
  bad:
  	pr_err("corrupt mdsmap
  ");

  	print_hex_dump(KERN_DEBUG, "mdsmap: ",
  		       DUMP_PREFIX_OFFSET, 16, 1,
  		       start, end - start, true);

  	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);
  }