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qed: Table, L2 cache, and cluster functions

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This patch adds code to look up data cluster offsets in the image via
the L1/L2 tables.  The L2 tables are writethrough cached in memory for
performance (each read/write requires a lookup so it is essential to
cache the tables).

With cluster lookup code in place it is possible to implement
bdrv_is_allocated() to query the number of contiguous
allocated/unallocated clusters.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2010-12-06 16:08:01 +00:00 committed by Kevin Wolf
parent 75411d236d
commit 298800cae7
8 changed files with 866 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Makefile.objs
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@ -20,7 +20,7 @@ block-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
block-nested-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vvfat.o
block-nested-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o
block-nested-y += qed.o
block-nested-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o
block-nested-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o
block-nested-$(CONFIG_WIN32) += raw-win32.o
block-nested-$(CONFIG_POSIX) += raw-posix.o

154
block/qed-cluster.c Normal file
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@ -0,0 +1,154 @@
/*
* QEMU Enhanced Disk Format Cluster functions
*
* 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 "qed.h"
/**
* Count the number of contiguous data clusters
*
* @s: QED state
* @table: L2 table
* @index: First cluster index
* @n: Maximum number of clusters
* @offset: Set to first cluster offset
*
* This function scans tables for contiguous allocated or free clusters.
*/
static unsigned int qed_count_contiguous_clusters(BDRVQEDState *s,
QEDTable *table,
unsigned int index,
unsigned int n,
uint64_t *offset)
{
unsigned int end = MIN(index + n, s->table_nelems);
uint64_t last = table->offsets[index];
unsigned int i;
*offset = last;
for (i = index + 1; i < end; i++) {
if (last == 0) {
/* Counting free clusters */
if (table->offsets[i] != 0) {
break;
}
} else {
/* Counting allocated clusters */
if (table->offsets[i] != last + s->header.cluster_size) {
break;
}
last = table->offsets[i];
}
}
return i - index;
}
typedef struct {
BDRVQEDState *s;
uint64_t pos;
size_t len;
QEDRequest *request;
/* User callback */
QEDFindClusterFunc *cb;
void *opaque;
} QEDFindClusterCB;
static void qed_find_cluster_cb(void *opaque, int ret)
{
QEDFindClusterCB *find_cluster_cb = opaque;
BDRVQEDState *s = find_cluster_cb->s;
QEDRequest *request = find_cluster_cb->request;
uint64_t offset = 0;
size_t len = 0;
unsigned int index;
unsigned int n;
if (ret) {
goto out;
}
index = qed_l2_index(s, find_cluster_cb->pos);
n = qed_bytes_to_clusters(s,
qed_offset_into_cluster(s, find_cluster_cb->pos) +
find_cluster_cb->len);
n = qed_count_contiguous_clusters(s, request->l2_table->table,
index, n, &offset);
ret = offset ? QED_CLUSTER_FOUND : QED_CLUSTER_L2;
len = MIN(find_cluster_cb->len, n * s->header.cluster_size -
qed_offset_into_cluster(s, find_cluster_cb->pos));
if (offset && !qed_check_cluster_offset(s, offset)) {
ret = -EINVAL;
}
out:
find_cluster_cb->cb(find_cluster_cb->opaque, ret, offset, len);
qemu_free(find_cluster_cb);
}
/**
* Find the offset of a data cluster
*
* @s: QED state
* @request: L2 cache entry
* @pos: Byte position in device
* @len: Number of bytes
* @cb: Completion function
* @opaque: User data for completion function
*
* This function translates a position in the block device to an offset in the
* image file. It invokes the cb completion callback to report back the
* translated offset or unallocated range in the image file.
*
* If the L2 table exists, request->l2_table points to the L2 table cache entry
* and the caller must free the reference when they are finished. The cache
* entry is exposed in this way to avoid callers having to read the L2 table
* again later during request processing. If request->l2_table is non-NULL it
* will be unreferenced before taking on the new cache entry.
*/
void qed_find_cluster(BDRVQEDState *s, QEDRequest *request, uint64_t pos,
size_t len, QEDFindClusterFunc *cb, void *opaque)
{
QEDFindClusterCB *find_cluster_cb;
uint64_t l2_offset;
/* Limit length to L2 boundary. Requests are broken up at the L2 boundary
* so that a request acts on one L2 table at a time.
*/
len = MIN(len, (((pos >> s->l1_shift) + 1) << s->l1_shift) - pos);
l2_offset = s->l1_table->offsets[qed_l1_index(s, pos)];
if (!l2_offset) {
cb(opaque, QED_CLUSTER_L1, 0, len);
return;
}
if (!qed_check_table_offset(s, l2_offset)) {
cb(opaque, -EINVAL, 0, 0);
return;
}
find_cluster_cb = qemu_malloc(sizeof(*find_cluster_cb));
find_cluster_cb->s = s;
find_cluster_cb->pos = pos;
find_cluster_cb->len = len;
find_cluster_cb->cb = cb;
find_cluster_cb->opaque = opaque;
find_cluster_cb->request = request;
qed_read_l2_table(s, request, l2_offset,
qed_find_cluster_cb, find_cluster_cb);
}

32
block/qed-gencb.c Normal file
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@ -0,0 +1,32 @@
/*
* QEMU Enhanced Disk Format
*
* Copyright IBM, Corp. 2010
*
* Authors:
* Stefan Hajnoczi <stefanha@linux.vnet.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 "qed.h"
void *gencb_alloc(size_t len, BlockDriverCompletionFunc *cb, void *opaque)
{
GenericCB *gencb = qemu_malloc(len);
gencb->cb = cb;
gencb->opaque = opaque;
return gencb;
}
void gencb_complete(void *opaque, int ret)
{
GenericCB *gencb = opaque;
BlockDriverCompletionFunc *cb = gencb->cb;
void *user_opaque = gencb->opaque;
qemu_free(gencb);
cb(user_opaque, ret);
}

173
block/qed-l2-cache.c Normal file
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@ -0,0 +1,173 @@
/*
* QEMU Enhanced Disk Format L2 Cache
*
* Copyright IBM, Corp. 2010
*
* Authors:
* 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.
*
*/
/*
* L2 table cache usage is as follows:
*
* An open image has one L2 table cache that is used to avoid accessing the
* image file for recently referenced L2 tables.
*
* Cluster offset lookup translates the logical offset within the block device
* to a cluster offset within the image file. This is done by indexing into
* the L1 and L2 tables which store cluster offsets. It is here where the L2
* table cache serves up recently referenced L2 tables.
*
* If there is a cache miss, that L2 table is read from the image file and
* committed to the cache. Subsequent accesses to that L2 table will be served
* from the cache until the table is evicted from the cache.
*
* L2 tables are also committed to the cache when new L2 tables are allocated
* in the image file. Since the L2 table cache is write-through, the new L2
* table is first written out to the image file and then committed to the
* cache.
*
* Multiple I/O requests may be using an L2 table cache entry at any given
* time. That means an entry may be in use across several requests and
* reference counting is needed to free the entry at the correct time. In
* particular, an entry evicted from the cache will only be freed once all
* references are dropped.
*
* An in-flight I/O request will hold a reference to a L2 table cache entry for
* the period during which it needs to access the L2 table. This includes
* cluster offset lookup, L2 table allocation, and L2 table update when a new
* data cluster has been allocated.
*
* An interesting case occurs when two requests need to access an L2 table that
* is not in the cache. Since the operation to read the table from the image
* file takes some time to complete, both requests may see a cache miss and
* start reading the L2 table from the image file. The first to finish will
* commit its L2 table into the cache. When the second tries to commit its
* table will be deleted in favor of the existing cache entry.
*/
#include "trace.h"
#include "qed.h"
/* Each L2 holds 2GB so this let's us fully cache a 100GB disk */
#define MAX_L2_CACHE_SIZE 50
/**
* Initialize the L2 cache
*/
void qed_init_l2_cache(L2TableCache *l2_cache)
{
QTAILQ_INIT(&l2_cache->entries);
l2_cache->n_entries = 0;
}
/**
* Free the L2 cache
*/
void qed_free_l2_cache(L2TableCache *l2_cache)
{
CachedL2Table *entry, *next_entry;
QTAILQ_FOREACH_SAFE(entry, &l2_cache->entries, node, next_entry) {
qemu_vfree(entry->table);
qemu_free(entry);
}
}
/**
* Allocate an uninitialized entry from the cache
*
* The returned entry has a reference count of 1 and is owned by the caller.
* The caller must allocate the actual table field for this entry and it must
* be freeable using qemu_vfree().
*/
CachedL2Table *qed_alloc_l2_cache_entry(L2TableCache *l2_cache)
{
CachedL2Table *entry;
entry = qemu_mallocz(sizeof(*entry));
entry->ref++;
trace_qed_alloc_l2_cache_entry(l2_cache, entry);
return entry;
}
/**
* Decrease an entry's reference count and free if necessary when the reference
* count drops to zero.
*/
void qed_unref_l2_cache_entry(CachedL2Table *entry)
{
if (!entry) {
return;
}
entry->ref--;
trace_qed_unref_l2_cache_entry(entry, entry->ref);
if (entry->ref == 0) {
qemu_vfree(entry->table);
qemu_free(entry);
}
}
/**
* Find an entry in the L2 cache. This may return NULL and it's up to the
* caller to satisfy the cache miss.
*
* For a cached entry, this function increases the reference count and returns
* the entry.
*/
CachedL2Table *qed_find_l2_cache_entry(L2TableCache *l2_cache, uint64_t offset)
{
CachedL2Table *entry;
QTAILQ_FOREACH(entry, &l2_cache->entries, node) {
if (entry->offset == offset) {
trace_qed_find_l2_cache_entry(l2_cache, entry, offset, entry->ref);
entry->ref++;
return entry;
}
}
return NULL;
}
/**
* Commit an L2 cache entry into the cache. This is meant to be used as part of
* the process to satisfy a cache miss. A caller would allocate an entry which
* is not actually in the L2 cache and then once the entry was valid and
* present on disk, the entry can be committed into the cache.
*
* Since the cache is write-through, it's important that this function is not
* called until the entry is present on disk and the L1 has been updated to
* point to the entry.
*
* N.B. This function steals a reference to the l2_table from the caller so the
* caller must obtain a new reference by issuing a call to
* qed_find_l2_cache_entry().
*/
void qed_commit_l2_cache_entry(L2TableCache *l2_cache, CachedL2Table *l2_table)
{
CachedL2Table *entry;
entry = qed_find_l2_cache_entry(l2_cache, l2_table->offset);
if (entry) {
qed_unref_l2_cache_entry(entry);
qed_unref_l2_cache_entry(l2_table);
return;
}
if (l2_cache->n_entries >= MAX_L2_CACHE_SIZE) {
entry = QTAILQ_FIRST(&l2_cache->entries);
QTAILQ_REMOVE(&l2_cache->entries, entry, node);
l2_cache->n_entries--;
qed_unref_l2_cache_entry(entry);
}
l2_cache->n_entries++;
QTAILQ_INSERT_TAIL(&l2_cache->entries, l2_table, node);
}

319
block/qed-table.c Normal file
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@ -0,0 +1,319 @@
/*
* 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->iov.iov_len / 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,
read_table_cb->iov.iov_len / 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->iov.iov_len / 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;
async_context_push();
qed_read_table(s, s->header.l1_table_offset,
s->l1_table, qed_sync_cb, &ret);
while (ret == -EINPROGRESS) {
qemu_aio_wait();
}
async_context_pop();
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;
async_context_push();
qed_write_l1_table(s, index, n, qed_sync_cb, &ret);
while (ret == -EINPROGRESS) {
qemu_aio_wait();
}
async_context_pop();
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;
if (ret) {
/* can't trust loaded L2 table anymore */
qed_unref_l2_cache_entry(l2_table);
request->l2_table = NULL;
} else {
l2_table->offset = read_l2_table_cb->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_table->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;
async_context_push();
qed_read_l2_table(s, request, offset, qed_sync_cb, &ret);
while (ret == -EINPROGRESS) {
qemu_aio_wait();
}
async_context_pop();
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;
async_context_push();
qed_write_l2_table(s, request, index, n, flush, qed_sync_cb, &ret);
while (ret == -EINPROGRESS) {
qemu_aio_wait();
}
async_context_pop();
return ret;
}

54
block/qed.c
View File

@ -155,6 +155,13 @@ static int qed_read_string(BlockDriverState *file, uint64_t offset, size_t n,
return 0;
}
QEDTable *qed_alloc_table(BDRVQEDState *s)
{
/* Honor O_DIRECT memory alignment requirements */
return qemu_blockalign(s->bs,
s->header.cluster_size * s->header.table_size);
}
static int bdrv_qed_open(BlockDriverState *bs, int flags)
{
BDRVQEDState *s = bs->opaque;
@ -244,11 +251,23 @@ static int bdrv_qed_open(BlockDriverState *bs, int flags)
bdrv_flush(bs->file);
}
s->l1_table = qed_alloc_table(s);
qed_init_l2_cache(&s->l2_cache);
ret = qed_read_l1_table_sync(s);
if (ret) {
qed_free_l2_cache(&s->l2_cache);
qemu_vfree(s->l1_table);
}
return ret;
}
static void bdrv_qed_close(BlockDriverState *bs)
{
BDRVQEDState *s = bs->opaque;
qed_free_l2_cache(&s->l2_cache);
qemu_vfree(s->l1_table);
}
static int bdrv_qed_flush(BlockDriverState *bs)
@ -368,10 +387,43 @@ static int bdrv_qed_create(const char *filename, QEMUOptionParameter *options)
backing_file, backing_fmt);
}
typedef struct {
int is_allocated;
int *pnum;
} QEDIsAllocatedCB;
static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len)
{
QEDIsAllocatedCB *cb = opaque;
*cb->pnum = len / BDRV_SECTOR_SIZE;
cb->is_allocated = ret == QED_CLUSTER_FOUND;
}
static int bdrv_qed_is_allocated(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int *pnum)
{
return -ENOTSUP;
BDRVQEDState *s = bs->opaque;
uint64_t pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE;
size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE;
QEDIsAllocatedCB cb = {
.is_allocated = -1,
.pnum = pnum,
};
QEDRequest request = { .l2_table = NULL };
async_context_push();
qed_find_cluster(s, &request, pos, len, qed_is_allocated_cb, &cb);
while (cb.is_allocated == -1) {
qemu_aio_wait();
}
async_context_pop();
qed_unref_l2_cache_entry(request.l2_table);
return cb.is_allocated;
}
static int bdrv_qed_make_empty(BlockDriverState *bs)

123
block/qed.h
View File

@ -95,17 +95,119 @@ typedef struct {
uint32_t backing_filename_size; /* in bytes */
} QEDHeader;
typedef struct {
uint64_t offsets[0]; /* in bytes */
} QEDTable;
/* The L2 cache is a simple write-through cache for L2 structures */
typedef struct CachedL2Table {
QEDTable *table;
uint64_t offset; /* offset=0 indicates an invalidate entry */
QTAILQ_ENTRY(CachedL2Table) node;
int ref;
} CachedL2Table;
typedef struct {
QTAILQ_HEAD(, CachedL2Table) entries;
unsigned int n_entries;
} L2TableCache;
typedef struct QEDRequest {
CachedL2Table *l2_table;
} QEDRequest;
typedef struct {
BlockDriverState *bs; /* device */
uint64_t file_size; /* length of image file, in bytes */
QEDHeader header; /* always cpu-endian */
QEDTable *l1_table;
L2TableCache l2_cache; /* l2 table cache */
uint32_t table_nelems;
uint32_t l1_shift;
uint32_t l2_shift;
uint32_t l2_mask;
} BDRVQEDState;
enum {
QED_CLUSTER_FOUND, /* cluster found */
QED_CLUSTER_L2, /* cluster missing in L2 */
QED_CLUSTER_L1, /* cluster missing in L1 */
};
/**
* qed_find_cluster() completion callback
*
* @opaque: User data for completion callback
* @ret: QED_CLUSTER_FOUND Success
* QED_CLUSTER_L2 Data cluster unallocated in L2
* QED_CLUSTER_L1 L2 unallocated in L1
* -errno POSIX error occurred
* @offset: Data cluster offset
* @len: Contiguous bytes starting from cluster offset
*
* This function is invoked when qed_find_cluster() completes.
*
* On success ret is QED_CLUSTER_FOUND and offset/len are a contiguous range
* in the image file.
*
* On failure ret is QED_CLUSTER_L2 or QED_CLUSTER_L1 for missing L2 or L1
* table offset, respectively. len is number of contiguous unallocated bytes.
*/
typedef void QEDFindClusterFunc(void *opaque, int ret, uint64_t offset, size_t len);
/**
* Generic callback for chaining async callbacks
*/
typedef struct {
BlockDriverCompletionFunc *cb;
void *opaque;
} GenericCB;
void *gencb_alloc(size_t len, BlockDriverCompletionFunc *cb, void *opaque);
void gencb_complete(void *opaque, int ret);
/**
* L2 cache functions
*/
void qed_init_l2_cache(L2TableCache *l2_cache);
void qed_free_l2_cache(L2TableCache *l2_cache);
CachedL2Table *qed_alloc_l2_cache_entry(L2TableCache *l2_cache);
void qed_unref_l2_cache_entry(CachedL2Table *entry);
CachedL2Table *qed_find_l2_cache_entry(L2TableCache *l2_cache, uint64_t offset);
void qed_commit_l2_cache_entry(L2TableCache *l2_cache, CachedL2Table *l2_table);
/**
* Table I/O functions
*/
int qed_read_l1_table_sync(BDRVQEDState *s);
void qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n,
BlockDriverCompletionFunc *cb, void *opaque);
int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,
unsigned int n);
int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
uint64_t offset);
void qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset,
BlockDriverCompletionFunc *cb, void *opaque);
void qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,
unsigned int index, unsigned int n, bool flush,
BlockDriverCompletionFunc *cb, void *opaque);
int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
unsigned int index, unsigned int n, bool flush);
/**
* Cluster functions
*/
void qed_find_cluster(BDRVQEDState *s, QEDRequest *request, uint64_t pos,
size_t len, QEDFindClusterFunc *cb, void *opaque);
/**
* Consistency check
*/
int qed_check(BDRVQEDState *s, BdrvCheckResult *result, bool fix);
QEDTable *qed_alloc_table(BDRVQEDState *s);
/**
* Round down to the start of a cluster
*/
@ -114,6 +216,27 @@ static inline uint64_t qed_start_of_cluster(BDRVQEDState *s, uint64_t offset)
return offset & ~(uint64_t)(s->header.cluster_size - 1);
}
static inline uint64_t qed_offset_into_cluster(BDRVQEDState *s, uint64_t offset)
{
return offset & (s->header.cluster_size - 1);
}
static inline unsigned int qed_bytes_to_clusters(BDRVQEDState *s, size_t bytes)
{
return qed_start_of_cluster(s, bytes + (s->header.cluster_size - 1)) /
(s->header.cluster_size - 1);
}
static inline unsigned int qed_l1_index(BDRVQEDState *s, uint64_t pos)
{
return pos >> s->l1_shift;
}
static inline unsigned int qed_l2_index(BDRVQEDState *s, uint64_t pos)
{
return (pos >> s->l2_shift) & s->l2_mask;
}
/**
* Test if a cluster offset is valid
*/

11
trace-events
View File

@ -192,3 +192,14 @@ disable sun4m_iommu_bad_addr(uint64_t addr) "bad addr %"PRIx64""
# vl.c
disable vm_state_notify(int running, int reason) "running %d reason %d"
# block/qed-l2-cache.c
disable qed_alloc_l2_cache_entry(void *l2_cache, void *entry) "l2_cache %p entry %p"
disable qed_unref_l2_cache_entry(void *entry, int ref) "entry %p ref %d"
disable qed_find_l2_cache_entry(void *l2_cache, void *entry, uint64_t offset, int ref) "l2_cache %p entry %p offset %"PRIu64" ref %d"
# block/qed-table.c
disable qed_read_table(void *s, uint64_t offset, void *table) "s %p offset %"PRIu64" table %p"
disable qed_read_table_cb(void *s, void *table, int ret) "s %p table %p ret %d"
disable qed_write_table(void *s, uint64_t offset, void *table, unsigned int index, unsigned int n) "s %p offset %"PRIu64" table %p index %u n %u"
disable qed_write_table_cb(void *s, void *table, int flush, int ret) "s %p table %p flush %d ret %d"