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1f01e50b83
This makes the driver thread-safe. The CoMutex is dropped temporarily while accessing the data clusters or the backing file. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20170629132749.997-10-pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
208 lines
5.7 KiB
C
208 lines
5.7 KiB
C
/*
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* QEMU Enhanced Disk Format Table I/O
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*
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* Copyright IBM, Corp. 2010
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*
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* Authors:
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* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU LGPL, version 2 or later.
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* See the COPYING.LIB file in the top-level directory.
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*
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*/
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#include "qemu/osdep.h"
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#include "trace.h"
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#include "qemu/sockets.h" /* for EINPROGRESS on Windows */
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#include "qed.h"
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#include "qemu/bswap.h"
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/* Called either from qed_check or with table_lock held. */
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static int qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table)
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{
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QEMUIOVector qiov;
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int noffsets;
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int i, ret;
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struct iovec iov = {
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.iov_base = table->offsets,
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.iov_len = s->header.cluster_size * s->header.table_size,
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};
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qemu_iovec_init_external(&qiov, &iov, 1);
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trace_qed_read_table(s, offset, table);
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if (qemu_in_coroutine()) {
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qemu_co_mutex_unlock(&s->table_lock);
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}
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ret = bdrv_preadv(s->bs->file, offset, &qiov);
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if (qemu_in_coroutine()) {
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qemu_co_mutex_lock(&s->table_lock);
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}
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if (ret < 0) {
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goto out;
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}
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/* Byteswap offsets */
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noffsets = qiov.size / sizeof(uint64_t);
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for (i = 0; i < noffsets; i++) {
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table->offsets[i] = le64_to_cpu(table->offsets[i]);
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}
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ret = 0;
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out:
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/* Completion */
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trace_qed_read_table_cb(s, table, ret);
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return ret;
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}
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/**
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* Write out an updated part or all of a table
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*
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* @s: QED state
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* @offset: Offset of table in image file, in bytes
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* @table: Table
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* @index: Index of first element
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* @n: Number of elements
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* @flush: Whether or not to sync to disk
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*
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* Called either from qed_check or with table_lock held.
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*/
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static int qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
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unsigned int index, unsigned int n, bool flush)
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{
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unsigned int sector_mask = BDRV_SECTOR_SIZE / sizeof(uint64_t) - 1;
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unsigned int start, end, i;
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QEDTable *new_table;
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struct iovec iov;
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QEMUIOVector qiov;
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size_t len_bytes;
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int ret;
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trace_qed_write_table(s, offset, table, index, n);
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/* Calculate indices of the first and one after last elements */
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start = index & ~sector_mask;
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end = (index + n + sector_mask) & ~sector_mask;
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len_bytes = (end - start) * sizeof(uint64_t);
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new_table = qemu_blockalign(s->bs, len_bytes);
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iov = (struct iovec) {
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.iov_base = new_table->offsets,
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.iov_len = len_bytes,
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};
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qemu_iovec_init_external(&qiov, &iov, 1);
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/* Byteswap table */
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for (i = start; i < end; i++) {
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uint64_t le_offset = cpu_to_le64(table->offsets[i]);
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new_table->offsets[i - start] = le_offset;
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}
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/* Adjust for offset into table */
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offset += start * sizeof(uint64_t);
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if (qemu_in_coroutine()) {
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qemu_co_mutex_unlock(&s->table_lock);
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}
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ret = bdrv_pwritev(s->bs->file, offset, &qiov);
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if (qemu_in_coroutine()) {
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qemu_co_mutex_lock(&s->table_lock);
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}
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trace_qed_write_table_cb(s, table, flush, ret);
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if (ret < 0) {
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goto out;
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}
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if (flush) {
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ret = bdrv_flush(s->bs);
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if (ret < 0) {
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goto out;
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}
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}
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ret = 0;
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out:
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qemu_vfree(new_table);
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return ret;
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}
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int qed_read_l1_table_sync(BDRVQEDState *s)
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{
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return qed_read_table(s, s->header.l1_table_offset, s->l1_table);
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}
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/* Called either from qed_check or with table_lock held. */
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int qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n)
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{
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BLKDBG_EVENT(s->bs->file, BLKDBG_L1_UPDATE);
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return qed_write_table(s, s->header.l1_table_offset,
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s->l1_table, index, n, false);
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}
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int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,
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unsigned int n)
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{
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return qed_write_l1_table(s, index, n);
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}
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/* Called either from qed_check or with table_lock held. */
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int qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
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{
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int ret;
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qed_unref_l2_cache_entry(request->l2_table);
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/* Check for cached L2 entry */
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request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
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if (request->l2_table) {
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return 0;
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}
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request->l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
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request->l2_table->table = qed_alloc_table(s);
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BLKDBG_EVENT(s->bs->file, BLKDBG_L2_LOAD);
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ret = qed_read_table(s, offset, request->l2_table->table);
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if (ret) {
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/* can't trust loaded L2 table anymore */
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qed_unref_l2_cache_entry(request->l2_table);
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request->l2_table = NULL;
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} else {
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request->l2_table->offset = offset;
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qed_commit_l2_cache_entry(&s->l2_cache, request->l2_table);
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/* This is guaranteed to succeed because we just committed the entry
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* to the cache.
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*/
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request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
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assert(request->l2_table != NULL);
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}
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return ret;
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}
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int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
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{
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return qed_read_l2_table(s, request, offset);
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}
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/* Called either from qed_check or with table_lock held. */
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int qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,
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unsigned int index, unsigned int n, bool flush)
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{
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BLKDBG_EVENT(s->bs->file, BLKDBG_L2_UPDATE);
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return qed_write_table(s, request->l2_table->offset,
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request->l2_table->table, index, n, flush);
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}
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int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
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unsigned int index, unsigned int n, bool flush)
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{
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return qed_write_l2_table(s, request, index, n, flush);
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}
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