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/*
* 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 "qemu/osdep.h"
#include "trace.h"
#include "qemu/sockets.h" /* for EINPROGRESS on Windows */
#include "qed.h"
#include "qemu/bswap.h"
/* Called with table_lock held. */
static int qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table)
{
QEMUIOVector qiov;
int noffsets;
int i, ret;
struct iovec iov = {
.iov_base = table->offsets,
.iov_len = s->header.cluster_size * s->header.table_size,
};
qemu_iovec_init_external(&qiov, &iov, 1);
trace_qed_read_table(s, offset, table);
qemu_co_mutex_unlock(&s->table_lock);
ret = bdrv_preadv(s->bs->file, offset, &qiov);
qemu_co_mutex_lock(&s->table_lock);
if (ret < 0) {
goto out;
}
/* Byteswap offsets */
noffsets = qiov.size / sizeof(uint64_t);
for (i = 0; i < noffsets; i++) {
table->offsets[i] = le64_to_cpu(table->offsets[i]);
}
ret = 0;
out:
/* Completion */
trace_qed_read_table_cb(s, table, ret);
return ret;
}
/**
* 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
*
* Called with table_lock held.
*/
static int qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
unsigned int index, unsigned int n, bool flush)
{
unsigned int sector_mask = BDRV_SECTOR_SIZE / sizeof(uint64_t) - 1;
unsigned int start, end, i;
QEDTable *new_table;
struct iovec iov;
QEMUIOVector qiov;
size_t len_bytes;
int ret;
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);
new_table = qemu_blockalign(s->bs, len_bytes);
iov = (struct iovec) {
.iov_base = new_table->offsets,
.iov_len = len_bytes,
};
qemu_iovec_init_external(&qiov, &iov, 1);
/* Byteswap table */
for (i = start; i < end; i++) {
uint64_t le_offset = cpu_to_le64(table->offsets[i]);
new_table->offsets[i - start] = le_offset;
}
/* Adjust for offset into table */
offset += start * sizeof(uint64_t);
qemu_co_mutex_unlock(&s->table_lock);
ret = bdrv_pwritev(s->bs->file, offset, &qiov);
qemu_co_mutex_lock(&s->table_lock);
trace_qed_write_table_cb(s, table, flush, ret);
if (ret < 0) {
goto out;
}
if (flush) {
ret = bdrv_flush(s->bs);
if (ret < 0) {
goto out;
}
}
ret = 0;
out:
qemu_vfree(new_table);
return ret;
}
int qed_read_l1_table_sync(BDRVQEDState *s)
{
return qed_read_table(s, s->header.l1_table_offset, s->l1_table);
}
/* Called with table_lock held. */
int qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n)
{
BLKDBG_EVENT(s->bs->file, BLKDBG_L1_UPDATE);
return qed_write_table(s, s->header.l1_table_offset,
s->l1_table, index, n, false);
}
int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,
unsigned int n)
{
return qed_write_l1_table(s, index, n);
}
/* Called with table_lock held. */
int qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
{
int ret;
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) {
return 0;
}
request->l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
request->l2_table->table = qed_alloc_table(s);
BLKDBG_EVENT(s->bs->file, BLKDBG_L2_LOAD);
ret = qed_read_table(s, offset, request->l2_table->table);
if (ret) {
/* can't trust loaded L2 table anymore */
qed_unref_l2_cache_entry(request->l2_table);
request->l2_table = NULL;
} else {
request->l2_table->offset = offset;
qed_commit_l2_cache_entry(&s->l2_cache, request->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, offset);
assert(request->l2_table != NULL);
}
return ret;
}
int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
{
return qed_read_l2_table(s, request, offset);
}
/* Called with table_lock held. */
int qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,
unsigned int index, unsigned int n, bool flush)
{
BLKDBG_EVENT(s->bs->file, BLKDBG_L2_UPDATE);
return qed_write_table(s, request->l2_table->offset,
request->l2_table->table, index, n, flush);
}
int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
unsigned int index, unsigned int n, bool flush)
{
return qed_write_l2_table(s, request, index, n, flush);
}
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