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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
#include <errno.h>
#include "common/ceph_context.h"
#include "common/debug.h"
#include "common/Mutex.h"
#include "include/Context.h"
#include "include/rados/librados.hpp"
#include "include/rbd/librbd.hpp"
#include "librbd/AioRequest.h"
#include "librbd/ImageCtx.h"
#include "librbd/internal.h"
#include "librbd/LibrbdWriteback.h"
#include "include/assert.h"
#define dout_subsys ceph_subsys_rbd
#undef dout_prefix
#define dout_prefix *_dout << "librbdwriteback: "
namespace librbd {
/**
* callback to finish a rados completion as a Context
*
* @param c completion
* @param arg Context* recast as void*
*/
void context_cb(rados_completion_t c, void *arg)
{
Context *con = reinterpret_cast<Context *>(arg);
con->finish(rados_aio_get_return_value(c));
delete con;
}
/**
* context to wrap another context in a Mutex
*
* @param cct cct
* @param c context to finish
* @param l mutex to lock
*/
class C_Request : public Context {
public:
C_Request(CephContext *cct, Context *c, Mutex *l)
: m_cct(cct), m_ctx(c), m_lock(l) {}
virtual ~C_Request() {}
void set_req(AioRequest *req);
virtual void finish(int r) {
ldout(m_cct, 20) << "aio_cb completing " << dendl;
{
Mutex::Locker l(*m_lock);
m_ctx->complete(r);
}
ldout(m_cct, 20) << "aio_cb finished" << dendl;
}
private:
CephContext *m_cct;
Context *m_ctx;
Mutex *m_lock;
};
LibrbdWriteback::LibrbdWriteback(ImageCtx *ictx, Mutex& lock)
: m_tid(0), m_lock(lock), m_ictx(ictx)
{
}
tid_t LibrbdWriteback::read(const object_t& oid,
const object_locator_t& oloc,
uint64_t off, uint64_t len, snapid_t snapid,
bufferlist *pbl, uint64_t trunc_size,
__u32 trunc_seq, Context *onfinish)
{
// on completion, take the mutex and then call onfinish.
Context *req = new C_Request(m_ictx->cct, onfinish, &m_lock);
librados::AioCompletion *rados_completion =
librados::Rados::aio_create_completion(req, context_cb, NULL);
int r = m_ictx->data_ctx.aio_read(oid.name, rados_completion, pbl,
len, off);
rados_completion->release();
assert(r >= 0);
return ++m_tid;
}
bool LibrbdWriteback::may_copy_on_write(const object_t& oid, uint64_t read_off, uint64_t read_len, snapid_t snapid)
{
m_ictx->snap_lock.Lock();
librados::snap_t snap_id = m_ictx->snap_id;
m_ictx->parent_lock.Lock();
uint64_t overlap = 0;
m_ictx->get_parent_overlap(snap_id, &overlap);
m_ictx->parent_lock.Unlock();
m_ictx->snap_lock.Unlock();
uint64_t object_no = oid_to_object_no(oid.name, m_ictx->object_prefix);
// reverse map this object extent onto the parent
vector<pair<uint64_t,uint64_t> > objectx;
Striper::extent_to_file(m_ictx->cct, &m_ictx->layout,
object_no, 0, m_ictx->layout.fl_object_size,
objectx);
uint64_t object_overlap = m_ictx->prune_parent_extents(objectx, overlap);
bool may = object_overlap > 0;
ldout(m_ictx->cct, 10) << "may_copy_on_write " << oid << " " << read_off << "~" << read_len << " = " << may << dendl;
return may;
}
tid_t LibrbdWriteback::write(const object_t& oid,
const object_locator_t& oloc,
uint64_t off, uint64_t len,
const SnapContext& snapc,
const bufferlist &bl, utime_t mtime,
uint64_t trunc_size, __u32 trunc_seq,
Context *oncommit)
{
m_ictx->snap_lock.Lock();
librados::snap_t snap_id = m_ictx->snap_id;
m_ictx->parent_lock.Lock();
uint64_t overlap = 0;
m_ictx->get_parent_overlap(snap_id, &overlap);
m_ictx->parent_lock.Unlock();
m_ictx->snap_lock.Unlock();
uint64_t object_no = oid_to_object_no(oid.name, m_ictx->object_prefix);
// reverse map this object extent onto the parent
vector<pair<uint64_t,uint64_t> > objectx;
Striper::extent_to_file(m_ictx->cct, &m_ictx->layout,
object_no, 0, m_ictx->layout.fl_object_size,
objectx);
uint64_t object_overlap = m_ictx->prune_parent_extents(objectx, overlap);
C_Request *req_comp = new C_Request(m_ictx->cct, oncommit, &m_lock);
AioWrite *req = new AioWrite(m_ictx, oid.name,
object_no, off, objectx, object_overlap,
bl, snapc, snap_id,
req_comp);
req->send();
return ++m_tid;
}
}
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