cls_rbd.cc

#include <iostream>
#include <string.h>
#include <stdlib.h>
#include <errno.h>

#include "include/types.h"
#include "objclass/objclass.h"

#include "include/rbd_types.h"

CLS_VER(1,3)
CLS_NAME(rbd)

cls_handle_t h_class;
cls_method_handle_t h_snapshots_list;
cls_method_handle_t h_snapshot_add;
cls_method_handle_t h_snapshot_remove;
cls_method_handle_t h_snapshot_revert;
cls_method_handle_t h_assign_bid;
cls_method_handle_t h_test_exec;

static int snap_read_header(cls_method_context_t hctx, bufferlist& bl)
{
  unsigned snap_count = 0;
  uint64_t snap_names_len = 0;
  int rc;
  struct rbd_obj_header_ondisk *header;

  cls_log("snapshots_list");

  while (1) {
    int len = sizeof(*header) +
      snap_count * sizeof(struct rbd_obj_snap_ondisk) +
      snap_names_len;

    rc = cls_cxx_read(hctx, 0, len, &bl);
    if (rc < 0)
      return rc;

    header = (struct rbd_obj_header_ondisk *)bl.c_str();

    if ((snap_count != header->snap_count) ||
        (snap_names_len != header->snap_names_len)) {
      snap_count = header->snap_count;
      snap_names_len = header->snap_names_len;
      bl.clear();
      continue;
    }
    break;
  }

  return 0;
}

int snapshots_list(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
{
  bufferlist bl;
  struct rbd_obj_header_ondisk *header;
  int rc = snap_read_header(hctx, bl);
  if (rc < 0)
    return rc;

  header = (struct rbd_obj_header_ondisk *)bl.c_str();
  bufferptr p(header->snap_names_len);
  char *buf = (char *)header;
  char *name = buf + sizeof(*header) + header->snap_count * sizeof(struct rbd_obj_snap_ondisk);
  char *end = name + header->snap_names_len;
  memcpy(p.c_str(),
         buf + sizeof(*header) + header->snap_count * sizeof(struct rbd_obj_snap_ondisk),
         header->snap_names_len);

  ::encode(header->snap_seq, *out);
  ::encode(header->snap_count, *out);

  for (unsigned i = 0; i < header->snap_count; i++) {
    string s = name;
    ::encode(header->snaps[i].id, *out);
    ::encode(header->snaps[i].image_size, *out);
    ::encode(s, *out);

    name += strlen(name) + 1;
    if (name > end)
      return -EIO;
  }

  return 0;
}

int snapshot_add(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
{
  bufferlist bl;
  struct rbd_obj_header_ondisk *header;
  bufferlist newbl;
  bufferptr header_bp(sizeof(*header));
  struct rbd_obj_snap_ondisk *new_snaps;

  int rc = snap_read_header(hctx, bl);
  if (rc < 0)
    return rc;

  header = (struct rbd_obj_header_ondisk *)bl.c_str();

  int snaps_id_ofs = sizeof(*header);
  int len = snaps_id_ofs;
  int names_ofs = snaps_id_ofs + sizeof(*new_snaps) * header->snap_count;
  const char *snap_name;
  const char *snap_names = ((char *)header) + names_ofs;
  const char *end = snap_names + header->snap_names_len;
  bufferlist::iterator iter = in->begin();
  string s;
  uint64_t snap_id;

  try {
    ::decode(s, iter);
    ::decode(snap_id, iter);
  } catch (const buffer::error &err) {
    return -EINVAL;
  }
  snap_name = s.c_str();


  const char *cur_snap_name;
  for (cur_snap_name = snap_names; cur_snap_name < end; cur_snap_name += strlen(cur_snap_name) + 1) {
    if (strncmp(cur_snap_name, snap_name, end - cur_snap_name) == 0)
      return -EEXIST;
  }
  if (cur_snap_name > end)
    return -EIO;

  int snap_name_len = strlen(snap_name);

  bufferptr new_names_bp(header->snap_names_len + snap_name_len + 1);
  bufferptr new_snaps_bp(sizeof(*new_snaps) * (header->snap_count + 1));

  /* copy snap names and append to new snap name */
  char *new_snap_names = new_names_bp.c_str();
  strcpy(new_snap_names, snap_name);
  memcpy(new_snap_names + snap_name_len + 1, snap_names, header->snap_names_len);

  /* append new snap id */
  new_snaps = (struct rbd_obj_snap_ondisk *)new_snaps_bp.c_str();
  memcpy(new_snaps + 1, header->snaps, sizeof(*new_snaps) * header->snap_count);

  header->snap_count = header->snap_count + 1;
  header->snap_names_len = header->snap_names_len + snap_name_len + 1;
  header->snap_seq = snap_id;

  new_snaps[0].id = snap_id;
  new_snaps[0].image_size = header->image_size;

  len += sizeof(*new_snaps) * header->snap_count + header->snap_names_len;

  memcpy(header_bp.c_str(), header, sizeof(*header));

  newbl.push_back(header_bp);
  newbl.push_back(new_snaps_bp);
  newbl.push_back(new_names_bp);

  rc = cls_cxx_write_full(hctx, &newbl);
  if (rc < 0)
    return rc;

  return 0;
}

int snapshot_revert(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
{
  bufferlist bl;
  struct rbd_obj_header_ondisk *header;
  bufferlist newbl;
  bufferptr header_bp(sizeof(*header));
  struct rbd_obj_snap_ondisk *new_snaps;

  int rc = snap_read_header(hctx, bl);
  if (rc < 0)
    return rc;

  header = (struct rbd_obj_header_ondisk *)bl.c_str();

  int snaps_id_ofs = sizeof(*header);
  int names_ofs = snaps_id_ofs + sizeof(*new_snaps) * header->snap_count;
  const char *snap_name;
  const char *snap_names = ((char *)header) + names_ofs;
  const char *end = snap_names + header->snap_names_len;
  bufferlist::iterator iter = in->begin();
  string s;
  int i;
  bool found = false;
  struct rbd_obj_snap_ondisk snap;

  try {
    ::decode(s, iter);
  } catch (const buffer::error &err) {
    return -EINVAL;
  }
  snap_name = s.c_str();

  for (i = 0; snap_names < end; i++) {
    if (strcmp(snap_names, snap_name) == 0) {
      snap = header->snaps[i];
      found = true;
      break;
    }
    snap_names += strlen(snap_names) + 1;
  }
  if (!found) {
    CLS_LOG("couldn't find snap %s\n",snap_name);
    return -ENOENT;
  }

  header->image_size = snap.image_size;
  header->snap_seq = header->snap_seq + 1;

  snap_names += strlen(snap_names) + 1;
  i++;

  header->snap_count = header->snap_count - i;
  bufferptr new_names_bp(end - snap_names);
  bufferptr new_snaps_bp(sizeof(header->snaps[0]) * header->snap_count);

  memcpy(header_bp.c_str(), header, sizeof(*header));
  newbl.push_back(header_bp);

  if (header->snap_count) {
    memcpy(new_snaps_bp.c_str(), header->snaps + i, sizeof(header->snaps[0]) * header->snap_count);
    memcpy(new_names_bp.c_str(), snap_names, end - snap_names);
    newbl.push_back(new_snaps_bp);
    newbl.push_back(new_names_bp);
  }

  rc = cls_cxx_write_full(hctx, &newbl);
  if (rc < 0)
    return rc;

  ::encode(snap.id, *out);

  return out->length();
}

int snapshot_remove(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
{
  bufferlist bl;
  struct rbd_obj_header_ondisk *header;
  bufferlist newbl;
  bufferptr header_bp(sizeof(*header));
  struct rbd_obj_snap_ondisk *new_snaps;

  int rc = snap_read_header(hctx, bl);
  if (rc < 0)
    return rc;

  header = (struct rbd_obj_header_ondisk *)bl.c_str();

  int snaps_id_ofs = sizeof(*header);
  int names_ofs = snaps_id_ofs + sizeof(*new_snaps) * header->snap_count;
  const char *snap_name;
  const char *snap_names = ((char *)header) + names_ofs;
  const char *orig_names = snap_names;
  const char *end = snap_names + header->snap_names_len;
  bufferlist::iterator iter = in->begin();
  string s;
  unsigned i;
  bool found = false;
  struct rbd_obj_snap_ondisk snap;

  try {
    ::decode(s, iter);
  } catch (const buffer::error &err) {
    return -EINVAL;
  }
  snap_name = s.c_str();

  for (i = 0; snap_names < end; i++) {
    if (strcmp(snap_names, snap_name) == 0) {
      snap = header->snaps[i];
      found = true;
      break;
    }
    snap_names += strlen(snap_names) + 1;
  }
  if (!found) {
    CLS_LOG("couldn't find snap %s\n",snap_name);
    return -ENOENT;
  }

  header->snap_names_len  = header->snap_names_len - (s.length() + 1);
  header->snap_count = header->snap_count - 1;

  bufferptr new_names_bp(header->snap_names_len);
  bufferptr new_snaps_bp(sizeof(header->snaps[0]) * header->snap_count);

  memcpy(header_bp.c_str(), header, sizeof(*header));
  newbl.push_back(header_bp);

  if (header->snap_count) {
    int snaps_len = 0;
    int names_len = 0;
    CLS_LOG("i=%d\n", i);
    if (i > 0) {
      snaps_len = sizeof(header->snaps[0]) * i;
      names_len =  snap_names - orig_names;
      memcpy(new_snaps_bp.c_str(), header->snaps, snaps_len);
      memcpy(new_names_bp.c_str(), orig_names, names_len);
    }
    snap_names += s.length() + 1;

    if (i < header->snap_count) {
      memcpy(new_snaps_bp.c_str() + snaps_len,
             header->snaps + i + 1,
             sizeof(header->snaps[0]) * (header->snap_count - i));
      memcpy(new_names_bp.c_str() + names_len, snap_names , end - snap_names);
    }
    newbl.push_back(new_snaps_bp);
    newbl.push_back(new_names_bp);
  }

  rc = cls_cxx_write_full(hctx, &newbl);
  if (rc < 0)
    return rc;

  return 0;

}


/* assign block id. This method should be called on the rbd_info object */
int rbd_assign_bid(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
{
  struct rbd_info info;
  int rc;
  bufferlist bl;

  rc = cls_cxx_read(hctx, 0, sizeof(info), &bl);
  if (rc < 0 && rc != -EEXIST)
    return rc;

  if (rc && rc < (int)sizeof(info)) {
    CLS_LOG("bad rbd_info object, read %d bytes, expected %d", rc, sizeof(info));
    return -EIO;
  }

  uint64_t max_id;
  if (rc) {
    memcpy(&info, bl.c_str(), sizeof(info));
    max_id = info.max_id + 1;
    info.max_id = max_id;
  } else {
    memset(&info, 0, sizeof(info));
    max_id = 0;
  }

  bufferlist newbl;
  bufferptr bp(sizeof(info));
  memcpy(bp.c_str(), &info, sizeof(info));
  newbl.push_back(bp);
  rc = cls_cxx_write_full(hctx, &newbl);
  if (rc < 0) {
    CLS_LOG("error writing rbd_info, got rc=%d", rc);
    return rc;
  }

  ::encode(max_id, *out);

  return out->length();
}

/* Used for testing rados_exec */
static int test_exec(cls_method_context_t hctx, bufferlist *in, bufferlist *out)
{
  bufferlist bl;
  std::string testing123("testing123");
  ::encode(testing123, *out);
  return out->length();
}

void __cls_init()
{
  CLS_LOG("Loaded rbd class!");

  cls_register("rbd", &h_class);
  cls_register_cxx_method(h_class, "snap_list", CLS_METHOD_RD | CLS_METHOD_PUBLIC, snapshots_list, &h_snapshots_list);
  cls_register_cxx_method(h_class, "snap_add", CLS_METHOD_RD | CLS_METHOD_WR | CLS_METHOD_PUBLIC, snapshot_add, &h_snapshot_add);
  cls_register_cxx_method(h_class, "snap_remove", CLS_METHOD_RD | CLS_METHOD_WR | CLS_METHOD_PUBLIC, snapshot_remove, &h_snapshot_remove);
  cls_register_cxx_method(h_class, "snap_revert", CLS_METHOD_RD | CLS_METHOD_WR | CLS_METHOD_PUBLIC, snapshot_revert, &h_snapshot_revert);

  /* assign a unique block id for rbd blocks */
  cls_register_cxx_method(h_class, "assign_bid", CLS_METHOD_RD | CLS_METHOD_WR | CLS_METHOD_PUBLIC, rbd_assign_bid, &h_assign_bid);

  cls_register_cxx_method(h_class, "test_exec", CLS_METHOD_RD | CLS_METHOD_PUBLIC, test_exec, &h_test_exec);

  return;
}