qemu/block/qed-table.c
Zhi Yong Wu 23e9a39e7d qed: adjust the way to get nb_sectors
This patch is only to refactor some lines of codes to get better and more robust codes.

As you have seen, in qed_read_table_cb() it's nice to
use qiov->size because that function doesn't obviously use a single
struct iovec.

In other two functions, if qiov use more than one struct iovec, the existing way will get wrong nb_sectors.
To make the code more robust, it will be nicer to refactor the existing way as below.

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Acked-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-12-05 14:51:34 +01:00

306 lines
8.7 KiB
C

/*
* QEMU Enhanced Disk Format Table I/O
*
* Copyright IBM, Corp. 2010
*
* Authors:
* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#include "trace.h"
#include "qemu_socket.h" /* for EINPROGRESS on Windows */
#include "qed.h"
typedef struct {
GenericCB gencb;
BDRVQEDState *s;
QEDTable *table;
struct iovec iov;
QEMUIOVector qiov;
} QEDReadTableCB;
static void qed_read_table_cb(void *opaque, int ret)
{
QEDReadTableCB *read_table_cb = opaque;
QEDTable *table = read_table_cb->table;
int noffsets = read_table_cb->qiov.size / sizeof(uint64_t);
int i;
/* Handle I/O error */
if (ret) {
goto out;
}
/* Byteswap offsets */
for (i = 0; i < noffsets; i++) {
table->offsets[i] = le64_to_cpu(table->offsets[i]);
}
out:
/* Completion */
trace_qed_read_table_cb(read_table_cb->s, read_table_cb->table, ret);
gencb_complete(&read_table_cb->gencb, ret);
}
static void qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
BlockDriverCompletionFunc *cb, void *opaque)
{
QEDReadTableCB *read_table_cb = gencb_alloc(sizeof(*read_table_cb),
cb, opaque);
QEMUIOVector *qiov = &read_table_cb->qiov;
BlockDriverAIOCB *aiocb;
trace_qed_read_table(s, offset, table);
read_table_cb->s = s;
read_table_cb->table = table;
read_table_cb->iov.iov_base = table->offsets,
read_table_cb->iov.iov_len = s->header.cluster_size * s->header.table_size,
qemu_iovec_init_external(qiov, &read_table_cb->iov, 1);
aiocb = bdrv_aio_readv(s->bs->file, offset / BDRV_SECTOR_SIZE, qiov,
qiov->size / BDRV_SECTOR_SIZE,
qed_read_table_cb, read_table_cb);
if (!aiocb) {
qed_read_table_cb(read_table_cb, -EIO);
}
}
typedef struct {
GenericCB gencb;
BDRVQEDState *s;
QEDTable *orig_table;
QEDTable *table;
bool flush; /* flush after write? */
struct iovec iov;
QEMUIOVector qiov;
} QEDWriteTableCB;
static void qed_write_table_cb(void *opaque, int ret)
{
QEDWriteTableCB *write_table_cb = opaque;
trace_qed_write_table_cb(write_table_cb->s,
write_table_cb->orig_table,
write_table_cb->flush,
ret);
if (ret) {
goto out;
}
if (write_table_cb->flush) {
/* We still need to flush first */
write_table_cb->flush = false;
bdrv_aio_flush(write_table_cb->s->bs, qed_write_table_cb,
write_table_cb);
return;
}
out:
qemu_vfree(write_table_cb->table);
gencb_complete(&write_table_cb->gencb, ret);
return;
}
/**
* Write out an updated part or all of a table
*
* @s: QED state
* @offset: Offset of table in image file, in bytes
* @table: Table
* @index: Index of first element
* @n: Number of elements
* @flush: Whether or not to sync to disk
* @cb: Completion function
* @opaque: Argument for completion function
*/
static void qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
unsigned int index, unsigned int n, bool flush,
BlockDriverCompletionFunc *cb, void *opaque)
{
QEDWriteTableCB *write_table_cb;
BlockDriverAIOCB *aiocb;
unsigned int sector_mask = BDRV_SECTOR_SIZE / sizeof(uint64_t) - 1;
unsigned int start, end, i;
size_t len_bytes;
trace_qed_write_table(s, offset, table, index, n);
/* Calculate indices of the first and one after last elements */
start = index & ~sector_mask;
end = (index + n + sector_mask) & ~sector_mask;
len_bytes = (end - start) * sizeof(uint64_t);
write_table_cb = gencb_alloc(sizeof(*write_table_cb), cb, opaque);
write_table_cb->s = s;
write_table_cb->orig_table = table;
write_table_cb->flush = flush;
write_table_cb->table = qemu_blockalign(s->bs, len_bytes);
write_table_cb->iov.iov_base = write_table_cb->table->offsets;
write_table_cb->iov.iov_len = len_bytes;
qemu_iovec_init_external(&write_table_cb->qiov, &write_table_cb->iov, 1);
/* Byteswap table */
for (i = start; i < end; i++) {
uint64_t le_offset = cpu_to_le64(table->offsets[i]);
write_table_cb->table->offsets[i - start] = le_offset;
}
/* Adjust for offset into table */
offset += start * sizeof(uint64_t);
aiocb = bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE,
&write_table_cb->qiov,
write_table_cb->qiov.size / BDRV_SECTOR_SIZE,
qed_write_table_cb, write_table_cb);
if (!aiocb) {
qed_write_table_cb(write_table_cb, -EIO);
}
}
/**
* Propagate return value from async callback
*/
static void qed_sync_cb(void *opaque, int ret)
{
*(int *)opaque = ret;
}
int qed_read_l1_table_sync(BDRVQEDState *s)
{
int ret = -EINPROGRESS;
qed_read_table(s, s->header.l1_table_offset,
s->l1_table, qed_sync_cb, &ret);
while (ret == -EINPROGRESS) {
qemu_aio_wait();
}
return ret;
}
void qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n,
BlockDriverCompletionFunc *cb, void *opaque)
{
BLKDBG_EVENT(s->bs->file, BLKDBG_L1_UPDATE);
qed_write_table(s, s->header.l1_table_offset,
s->l1_table, index, n, false, cb, opaque);
}
int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,
unsigned int n)
{
int ret = -EINPROGRESS;
qed_write_l1_table(s, index, n, qed_sync_cb, &ret);
while (ret == -EINPROGRESS) {
qemu_aio_wait();
}
return ret;
}
typedef struct {
GenericCB gencb;
BDRVQEDState *s;
uint64_t l2_offset;
QEDRequest *request;
} QEDReadL2TableCB;
static void qed_read_l2_table_cb(void *opaque, int ret)
{
QEDReadL2TableCB *read_l2_table_cb = opaque;
QEDRequest *request = read_l2_table_cb->request;
BDRVQEDState *s = read_l2_table_cb->s;
CachedL2Table *l2_table = request->l2_table;
uint64_t l2_offset = read_l2_table_cb->l2_offset;
if (ret) {
/* can't trust loaded L2 table anymore */
qed_unref_l2_cache_entry(l2_table);
request->l2_table = NULL;
} else {
l2_table->offset = l2_offset;
qed_commit_l2_cache_entry(&s->l2_cache, l2_table);
/* This is guaranteed to succeed because we just committed the entry
* to the cache.
*/
request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset);
assert(request->l2_table != NULL);
}
gencb_complete(&read_l2_table_cb->gencb, ret);
}
void qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset,
BlockDriverCompletionFunc *cb, void *opaque)
{
QEDReadL2TableCB *read_l2_table_cb;
qed_unref_l2_cache_entry(request->l2_table);
/* Check for cached L2 entry */
request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
if (request->l2_table) {
cb(opaque, 0);
return;
}
request->l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
request->l2_table->table = qed_alloc_table(s);
read_l2_table_cb = gencb_alloc(sizeof(*read_l2_table_cb), cb, opaque);
read_l2_table_cb->s = s;
read_l2_table_cb->l2_offset = offset;
read_l2_table_cb->request = request;
BLKDBG_EVENT(s->bs->file, BLKDBG_L2_LOAD);
qed_read_table(s, offset, request->l2_table->table,
qed_read_l2_table_cb, read_l2_table_cb);
}
int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
{
int ret = -EINPROGRESS;
qed_read_l2_table(s, request, offset, qed_sync_cb, &ret);
while (ret == -EINPROGRESS) {
qemu_aio_wait();
}
return ret;
}
void qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,
unsigned int index, unsigned int n, bool flush,
BlockDriverCompletionFunc *cb, void *opaque)
{
BLKDBG_EVENT(s->bs->file, BLKDBG_L2_UPDATE);
qed_write_table(s, request->l2_table->offset,
request->l2_table->table, index, n, flush, cb, opaque);
}
int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
unsigned int index, unsigned int n, bool flush)
{
int ret = -EINPROGRESS;
qed_write_l2_table(s, request, index, n, flush, qed_sync_cb, &ret);
while (ret == -EINPROGRESS) {
qemu_aio_wait();
}
return ret;
}