block/qed-table.c - qemu - Git at Google

 /*
  * 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;

     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);
     bdrv_aio_readv(s->bs->file, offset / BDRV_SECTOR_SIZE, qiov,
                    qiov->size / BDRV_SECTOR_SIZE,
                    qed_read_table_cb, read_table_cb);
 }

 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);
 }

 /**
  * 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;
     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);

     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);
 }

 /**
  * 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;
 }
	/*
	* 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;

	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);
	bdrv_aio_readv(s->bs->file, offset / BDRV_SECTOR_SIZE, qiov,
	qiov->size / BDRV_SECTOR_SIZE,
	qed_read_table_cb, read_table_cb);
	}

	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);
	}

	/**
	* 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;
	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);

	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);
	}

	/**
	* 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;
	}