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[Qemu-devel] [PATCH v2 5/7] qed: Table, L2 cache, and cluster functions
|
From: |
Stefan Hajnoczi |
|
Subject: |
[Qemu-devel] [PATCH v2 5/7] qed: Table, L2 cache, and cluster functions |
|
Date: |
Fri, 8 Oct 2010 16:48:32 +0100 |
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 <address@hidden>
---
Makefile.objs | 2 +-
block/qed-cluster.c | 145 +++++++++++++++++++++++
block/qed-gencb.c | 32 +++++
block/qed-l2-cache.c | 132 +++++++++++++++++++++
block/qed-table.c | 316 ++++++++++++++++++++++++++++++++++++++++++++++++++
block/qed.c | 57 +++++++++-
block/qed.h | 108 +++++++++++++++++
trace-events | 6 +
8 files changed, 796 insertions(+), 2 deletions(-)
create mode 100644 block/qed-cluster.c
create mode 100644 block/qed-gencb.c
create mode 100644 block/qed-l2-cache.c
create mode 100644 block/qed-table.c
diff --git a/Makefile.objs b/Makefile.objs
index ff15795..7b3b19c 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -14,7 +14,7 @@ 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
diff --git a/block/qed-cluster.c b/block/qed-cluster.c
new file mode 100644
index 0000000..af65e5a
--- /dev/null
+++ b/block/qed-cluster.c
@@ -0,0 +1,145 @@
+/*
+ * QEMU Enhanced Disk Format Cluster functions
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ * Stefan Hajnoczi <address@hidden>
+ * Anthony Liguori <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING 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) {
+ ret = QED_CLUSTER_ERROR;
+ 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 = QED_CLUSTER_ERROR;
+ goto out;
+ }
+
+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
+ * @pos: Byte position in device
+ * @len: Number of bytes
+ * @cb: Completion function
+ * @opaque: User data for completion function
+ */
+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, QED_CLUSTER_ERROR, 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);
+}
diff --git a/block/qed-gencb.c b/block/qed-gencb.c
new file mode 100644
index 0000000..d389e12
--- /dev/null
+++ b/block/qed-gencb.c
@@ -0,0 +1,32 @@
+/*
+ * QEMU Enhanced Disk Format
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ * Stefan Hajnoczi <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING 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);
+}
diff --git a/block/qed-l2-cache.c b/block/qed-l2-cache.c
new file mode 100644
index 0000000..3b2bf6e
--- /dev/null
+++ b/block/qed-l2-cache.c
@@ -0,0 +1,132 @@
+/*
+ * QEMU Enhanced Disk Format L2 Cache
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ * Anthony Liguori <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#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,
+ L2TableAllocFunc *alloc_l2_table,
+ void *alloc_l2_table_opaque)
+{
+ QTAILQ_INIT(&l2_cache->entries);
+ l2_cache->n_entries = 0;
+ l2_cache->alloc_l2_table = alloc_l2_table;
+ l2_cache->alloc_l2_table_opaque = alloc_l2_table_opaque;
+}
+
+/**
+ * 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.
+ */
+CachedL2Table *qed_alloc_l2_cache_entry(L2TableCache *l2_cache)
+{
+ CachedL2Table *entry;
+
+ entry = qemu_mallocz(sizeof(*entry));
+ entry->table = l2_cache->alloc_l2_table(l2_cache->alloc_l2_table_opaque);
+ entry->ref++;
+
+ 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(L2TableCache *l2_cache, CachedL2Table *entry)
+{
+ if (!entry) {
+ return;
+ }
+
+ 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) {
+ 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(l2_cache, entry);
+ qed_unref_l2_cache_entry(l2_cache, 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(l2_cache, entry);
+ }
+
+ l2_cache->n_entries++;
+ QTAILQ_INSERT_TAIL(&l2_cache->entries, l2_table, node);
+}
diff --git a/block/qed-table.c b/block/qed-table.c
new file mode 100644
index 0000000..ba6faf0
--- /dev/null
+++ b/block/qed-table.c
@@ -0,0 +1,316 @@
+/*
+ * QEMU Enhanced Disk Format Table I/O
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ * Stefan Hajnoczi <address@hidden>
+ * Anthony Liguori <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING 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, 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(&s->l2_cache, 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(&s->l2_cache, 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);
+
+ 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;
+}
diff --git a/block/qed.c b/block/qed.c
index ea03798..6d7f4d7 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -139,6 +139,15 @@ static int qed_read_string(BlockDriverState *file,
uint64_t offset, size_t n,
return 0;
}
+static QEDTable *qed_alloc_table(void *opaque)
+{
+ BDRVQEDState *s = opaque;
+
+ /* 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;
@@ -207,11 +216,24 @@ static int bdrv_qed_open(BlockDriverState *bs, int flags)
}
}
}
+
+ s->l1_table = qed_alloc_table(s);
+ qed_init_l2_cache(&s->l2_cache, qed_alloc_table, s);
+
+ 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 void bdrv_qed_flush(BlockDriverState *bs)
@@ -336,10 +358,43 @@ 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(&s->l2_cache, request.l2_table);
+
+ return cb.is_allocated;
}
static int bdrv_qed_make_empty(BlockDriverState *bs)
diff --git a/block/qed.h b/block/qed.h
index 7ce95a7..9ea288f 100644
--- a/block/qed.h
+++ b/block/qed.h
@@ -96,16 +96,103 @@ typedef struct {
} 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;
+
+/**
+ * Allocate an L2 table
+ *
+ * This callback is used by the L2 cache to allocate tables without knowing
+ * their size or alignment requirements.
+ */
+typedef QEDTable *L2TableAllocFunc(void *opaque);
+
+typedef struct {
+ QTAILQ_HEAD(, CachedL2Table) entries;
+ unsigned int n_entries;
+ L2TableAllocFunc *alloc_l2_table;
+ void *alloc_l2_table_opaque;
+} 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_CLUSTER_ERROR, /* error looking up cluster */
+};
+
+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, L2TableAllocFunc
*alloc_l2_table, void *alloc_l2_table_opaque);
+void qed_free_l2_cache(L2TableCache *l2_cache);
+CachedL2Table *qed_alloc_l2_cache_entry(L2TableCache *l2_cache);
+void qed_unref_l2_cache_entry(L2TableCache *l2_cache, 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);
+
/**
* Utility functions
*/
@@ -114,6 +201,27 @@ 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
*/
diff --git a/trace-events b/trace-events
index f32c83f..a390196 100644
--- a/trace-events
+++ b/trace-events
@@ -67,3 +67,9 @@ disable cpu_out(unsigned int addr, unsigned int val) "addr
%#x value %u"
# balloon.c
# Since requests are raised via monitor, not many tracepoints are needed.
disable balloon_event(void *opaque, unsigned long addr) "opaque %p addr %lu"
+
+# 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 ret) "s %p table %p ret
%d"
--
1.7.1
- Re: [Qemu-devel] Re: [PATCH v2 6/7] qed: Read/write support, (continued)
- [Qemu-devel] [PATCH v2 1/7] qcow2: Make get_bits_from_size() common, Stefan Hajnoczi, 2010/10/08
- [Qemu-devel] [PATCH v2 5/7] qed: Table, L2 cache, and cluster functions,
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH v2 7/7] qed: Consistency check support, Stefan Hajnoczi, 2010/10/08
- [Qemu-devel] Re: [PATCH v2 0/7] qed: Add QEMU Enhanced Disk format, Kevin Wolf, 2010/10/11
- Re: [Qemu-devel] [PATCH v2 0/7] qed: Add QEMU Enhanced Disk format, Stefan Hajnoczi, 2010/10/16