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[Qemu-devel] [PATCH 4/7] qed: Add QEMU Enhanced Disk image format
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH 4/7] qed: Add QEMU Enhanced Disk image format |
Date: |
Thu, 23 Sep 2010 16:41:51 +0100 |
This patch introduces the qed on-disk layout and implements image
creation. Later patches add read/write and other functionality.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
Makefile.objs | 1 +
block/qed.c | 530 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
block/qed.h | 148 ++++++++++++++++
3 files changed, 679 insertions(+), 0 deletions(-)
create mode 100644 block/qed.c
create mode 100644 block/qed.h
diff --git a/Makefile.objs b/Makefile.objs
index 3ef6d80..bc3e6fb 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -14,6 +14,7 @@ block-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
block-nested-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o
vvfat.o
block-nested-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o
+block-nested-y += qed.o
block-nested-y += parallels.o nbd.o blkdebug.o sheepdog.o
block-nested-$(CONFIG_WIN32) += raw-win32.o
block-nested-$(CONFIG_POSIX) += raw-posix.o
diff --git a/block/qed.c b/block/qed.c
new file mode 100644
index 0000000..ea03798
--- /dev/null
+++ b/block/qed.c
@@ -0,0 +1,530 @@
+/*
+ * QEMU Enhanced Disk Format
+ *
+ * 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"
+
+static int bdrv_qed_probe(const uint8_t *buf, int buf_size,
+ const char *filename)
+{
+ const QEDHeader *header = (const void *)buf;
+
+ if (buf_size < sizeof(*header)) {
+ return 0;
+ }
+ if (le32_to_cpu(header->magic) != QED_MAGIC) {
+ return 0;
+ }
+ return 100;
+}
+
+static void qed_header_le_to_cpu(const QEDHeader *le, QEDHeader *cpu)
+{
+ cpu->magic = le32_to_cpu(le->magic);
+ cpu->cluster_size = le32_to_cpu(le->cluster_size);
+ cpu->table_size = le32_to_cpu(le->table_size);
+ cpu->header_size = le32_to_cpu(le->header_size);
+ cpu->features = le64_to_cpu(le->features);
+ cpu->compat_features = le64_to_cpu(le->compat_features);
+ cpu->l1_table_offset = le64_to_cpu(le->l1_table_offset);
+ cpu->image_size = le64_to_cpu(le->image_size);
+ cpu->backing_filename_offset = le32_to_cpu(le->backing_filename_offset);
+ cpu->backing_filename_size = le32_to_cpu(le->backing_filename_size);
+ cpu->backing_fmt_offset = le32_to_cpu(le->backing_fmt_offset);
+ cpu->backing_fmt_size = le32_to_cpu(le->backing_fmt_size);
+}
+
+static void qed_header_cpu_to_le(const QEDHeader *cpu, QEDHeader *le)
+{
+ le->magic = cpu_to_le32(cpu->magic);
+ le->cluster_size = cpu_to_le32(cpu->cluster_size);
+ le->table_size = cpu_to_le32(cpu->table_size);
+ le->header_size = cpu_to_le32(cpu->header_size);
+ le->features = cpu_to_le64(cpu->features);
+ le->compat_features = cpu_to_le64(cpu->compat_features);
+ le->l1_table_offset = cpu_to_le64(cpu->l1_table_offset);
+ le->image_size = cpu_to_le64(cpu->image_size);
+ le->backing_filename_offset = cpu_to_le32(cpu->backing_filename_offset);
+ le->backing_filename_size = cpu_to_le32(cpu->backing_filename_size);
+ le->backing_fmt_offset = cpu_to_le32(cpu->backing_fmt_offset);
+ le->backing_fmt_size = cpu_to_le32(cpu->backing_fmt_size);
+}
+
+static uint64_t qed_max_image_size(uint32_t cluster_size, uint32_t table_size)
+{
+ uint64_t table_entries;
+ uint64_t l2_size;
+
+ table_entries = (table_size * cluster_size) / sizeof(uint64_t);
+ l2_size = table_entries * cluster_size;
+
+ return l2_size * table_entries;
+}
+
+static bool qed_is_cluster_size_valid(uint32_t cluster_size)
+{
+ if (cluster_size < QED_MIN_CLUSTER_SIZE ||
+ cluster_size > QED_MAX_CLUSTER_SIZE) {
+ return false;
+ }
+ if (cluster_size & (cluster_size - 1)) {
+ return false; /* not power of 2 */
+ }
+ return true;
+}
+
+static bool qed_is_table_size_valid(uint32_t table_size)
+{
+ if (table_size < QED_MIN_TABLE_SIZE ||
+ table_size > QED_MAX_TABLE_SIZE) {
+ return false;
+ }
+ if (table_size & (table_size - 1)) {
+ return false; /* not power of 2 */
+ }
+ return true;
+}
+
+static bool qed_is_image_size_valid(uint64_t image_size, uint32_t cluster_size,
+ uint32_t table_size)
+{
+ if (image_size == 0) {
+ /* Supporting zero size images makes life harder because even the L1
+ * table is not needed. Make life simple and forbid zero size images.
+ */
+ return false;
+ }
+ if (image_size & (cluster_size - 1)) {
+ return false; /* not multiple of cluster size */
+ }
+ if (image_size > qed_max_image_size(cluster_size, table_size)) {
+ return false; /* image is too large */
+ }
+ return true;
+}
+
+/**
+ * Read a string of known length from the image file
+ *
+ * @file: Image file
+ * @offset: File offset to start of string, in bytes
+ * @n: String length in bytes
+ * @buf: Destination buffer
+ * @buflen: Destination buffer length in bytes
+ *
+ * The string is NUL-terminated.
+ */
+static int qed_read_string(BlockDriverState *file, uint64_t offset, size_t n,
+ char *buf, size_t buflen)
+{
+ int ret;
+ if (n >= buflen) {
+ return -EINVAL;
+ }
+ ret = bdrv_pread(file, offset, buf, n);
+ if (ret != n) {
+ return ret;
+ }
+ buf[n] = '\0';
+ return 0;
+}
+
+static int bdrv_qed_open(BlockDriverState *bs, int flags)
+{
+ BDRVQEDState *s = bs->opaque;
+ QEDHeader le_header;
+ int64_t file_size;
+ int ret;
+
+ s->bs = bs;
+
+ ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header));
+ if (ret != sizeof(le_header)) {
+ return ret;
+ }
+ qed_header_le_to_cpu(&le_header, &s->header);
+
+ if (s->header.magic != QED_MAGIC) {
+ return -ENOENT;
+ }
+ if (s->header.features & ~QED_FEATURE_MASK) {
+ return -ENOTSUP; /* image uses unsupported feature bits */
+ }
+ if (!qed_is_cluster_size_valid(s->header.cluster_size)) {
+ return -EINVAL;
+ }
+
+ /* Round up file size to the next cluster */
+ file_size = bdrv_getlength(bs->file);
+ if (file_size < 0) {
+ return file_size;
+ }
+ s->file_size = qed_start_of_cluster(s, file_size);
+
+ if (!qed_is_table_size_valid(s->header.table_size)) {
+ return -EINVAL;
+ }
+ if (!qed_is_image_size_valid(s->header.image_size,
+ s->header.cluster_size,
+ s->header.table_size)) {
+ return -EINVAL;
+ }
+ if (!qed_check_table_offset(s, s->header.l1_table_offset)) {
+ return -EINVAL;
+ }
+
+ s->table_nelems = (s->header.cluster_size * s->header.table_size) /
+ sizeof(uint64_t);
+ s->l2_shift = get_bits_from_size(s->header.cluster_size);
+ s->l2_mask = s->table_nelems - 1;
+ s->l1_shift = s->l2_shift + get_bits_from_size(s->l2_mask + 1);
+
+ if ((s->header.features & QED_F_BACKING_FILE)) {
+ ret = qed_read_string(bs->file, s->header.backing_filename_offset,
+ s->header.backing_filename_size,
bs->backing_file,
+ sizeof(bs->backing_file));
+ if (ret < 0) {
+ return ret;
+ }
+
+ if ((s->header.compat_features & QED_CF_BACKING_FORMAT)) {
+ ret = qed_read_string(bs->file, s->header.backing_fmt_offset,
+ s->header.backing_fmt_size,
+ bs->backing_format,
+ sizeof(bs->backing_format));
+ if (ret < 0) {
+ return ret;
+ }
+ }
+ }
+ return ret;
+}
+
+static void bdrv_qed_close(BlockDriverState *bs)
+{
+}
+
+static void bdrv_qed_flush(BlockDriverState *bs)
+{
+ bdrv_flush(bs->file);
+}
+
+static int qed_create(const char *filename, uint32_t cluster_size,
+ uint64_t image_size, uint32_t table_size,
+ const char *backing_file, const char *backing_fmt)
+{
+ QEDHeader header = {
+ .magic = QED_MAGIC,
+ .cluster_size = cluster_size,
+ .table_size = table_size,
+ .header_size = 1,
+ .features = 0,
+ .compat_features = 0,
+ .l1_table_offset = cluster_size,
+ .image_size = image_size,
+ };
+ QEDHeader le_header;
+ uint8_t *l1_table = NULL;
+ size_t l1_size = header.cluster_size * header.table_size;
+ int ret = 0;
+ int fd;
+
+ fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
+ if (fd < 0) {
+ return -errno;
+ }
+
+ if (backing_file) {
+ header.features |= QED_F_BACKING_FILE;
+ header.backing_filename_offset = sizeof(le_header);
+ header.backing_filename_size = strlen(backing_file);
+ if (backing_fmt) {
+ header.compat_features |= QED_CF_BACKING_FORMAT;
+ header.backing_fmt_offset = header.backing_filename_offset +
+ header.backing_filename_size;
+ header.backing_fmt_size = strlen(backing_fmt);
+ }
+ }
+
+ qed_header_cpu_to_le(&header, &le_header);
+ if (qemu_write_full(fd, &le_header, sizeof(le_header)) !=
sizeof(le_header)) {
+ ret = -errno;
+ goto out;
+ }
+ if (qemu_write_full(fd, backing_file, header.backing_filename_size) !=
header.backing_filename_size) {
+ ret = -errno;
+ goto out;
+ }
+ if (qemu_write_full(fd, backing_fmt, header.backing_fmt_size) !=
header.backing_fmt_size) {
+ ret = -errno;
+ goto out;
+ }
+
+ l1_table = qemu_mallocz(l1_size);
+ lseek(fd, header.l1_table_offset, SEEK_SET);
+ if (qemu_write_full(fd, l1_table, l1_size) != l1_size) {
+ ret = -errno;
+ goto out;
+ }
+
+out:
+ qemu_free(l1_table);
+ close(fd);
+ return ret;
+}
+
+static int bdrv_qed_create(const char *filename, QEMUOptionParameter *options)
+{
+ uint64_t image_size = 0;
+ uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE;
+ uint32_t table_size = QED_DEFAULT_TABLE_SIZE;
+ const char *backing_file = NULL;
+ const char *backing_fmt = NULL;
+
+ while (options && options->name) {
+ if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
+ image_size = options->value.n;
+ } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
+ backing_file = options->value.s;
+ } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) {
+ backing_fmt = options->value.s;
+ } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
+ if (options->value.n) {
+ cluster_size = options->value.n;
+ }
+ } else if (!strcmp(options->name, "table_size")) {
+ if (options->value.n) {
+ table_size = options->value.n;
+ }
+ }
+ options++;
+ }
+
+ if (!qed_is_cluster_size_valid(cluster_size)) {
+ fprintf(stderr, "QED cluster size must be within range [%u, %u] and
power of 2\n",
+ QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE);
+ return -EINVAL;
+ }
+ if (!qed_is_table_size_valid(table_size)) {
+ fprintf(stderr, "QED table size must be within range [%u, %u] and
power of 2\n",
+ QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE);
+ return -EINVAL;
+ }
+ if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) {
+ char buffer[64];
+
+ bytes_to_str(buffer, sizeof(buffer),
+ qed_max_image_size(cluster_size, table_size));
+
+ fprintf(stderr,
+ "QED image size must be a non-zero multiple of cluster size
and less than %s\n",
+ buffer);
+ return -EINVAL;
+ }
+
+ return qed_create(filename, cluster_size, image_size, table_size,
+ backing_file, backing_fmt);
+}
+
+static int bdrv_qed_is_allocated(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, int *pnum)
+{
+ return -ENOTSUP;
+}
+
+static int bdrv_qed_make_empty(BlockDriverState *bs)
+{
+ return -ENOTSUP;
+}
+
+static BlockDriverAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs,
+ int64_t sector_num,
+ QEMUIOVector *qiov, int nb_sectors,
+ BlockDriverCompletionFunc *cb,
+ void *opaque)
+{
+ return NULL;
+}
+
+static BlockDriverAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs,
+ int64_t sector_num,
+ QEMUIOVector *qiov, int
nb_sectors,
+ BlockDriverCompletionFunc *cb,
+ void *opaque)
+{
+ return NULL;
+}
+
+static BlockDriverAIOCB *bdrv_qed_aio_flush(BlockDriverState *bs,
+ BlockDriverCompletionFunc *cb,
+ void *opaque)
+{
+ return bdrv_aio_flush(bs->file, cb, opaque);
+}
+
+static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset)
+{
+ return -ENOTSUP;
+}
+
+static int64_t bdrv_qed_getlength(BlockDriverState *bs)
+{
+ BDRVQEDState *s = bs->opaque;
+ return s->header.image_size;
+}
+
+static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
+{
+ BDRVQEDState *s = bs->opaque;
+
+ memset(bdi, 0, sizeof(*bdi));
+ bdi->cluster_size = s->header.cluster_size;
+ return 0;
+}
+
+static int bdrv_qed_change_backing_file(BlockDriverState *bs,
+ const char *backing_file,
+ const char *backing_fmt)
+{
+ BDRVQEDState *s = bs->opaque;
+ QEDHeader new_header, le_header;
+ void *buffer;
+ size_t buffer_len, backing_file_len, backing_fmt_len;
+ int ret;
+
+ /* Refuse to set backing filename if unknown compat feature bits are
+ * active. If the image uses an unknown compat feature then we may not
+ * know the layout of data following the header structure and cannot safely
+ * add a new string.
+ */
+ if (backing_file && (s->header.compat_features &
+ ~QED_COMPAT_FEATURE_MASK)) {
+ return -ENOTSUP;
+ }
+
+ memcpy(&new_header, &s->header, sizeof(new_header));
+
+ new_header.features &= ~QED_F_BACKING_FILE;
+ new_header.compat_features &= ~QED_CF_BACKING_FORMAT;
+
+ /* Adjust feature flags */
+ if (backing_file) {
+ new_header.features |= QED_F_BACKING_FILE;
+ if (backing_fmt) {
+ new_header.compat_features |= QED_CF_BACKING_FORMAT;
+ }
+ }
+
+ /* Calculate new header size */
+ backing_file_len = backing_fmt_len = 0;
+
+ if (backing_file) {
+ backing_file_len = strlen(backing_file);
+ if (backing_fmt) {
+ backing_fmt_len = strlen(backing_fmt);
+ }
+ }
+
+ buffer_len = sizeof(new_header);
+ new_header.backing_filename_offset = buffer_len;
+ new_header.backing_filename_size = backing_file_len;
+ buffer_len += backing_file_len;
+ new_header.backing_fmt_offset = buffer_len;
+ new_header.backing_fmt_size = backing_fmt_len;
+ buffer_len += backing_fmt_len;
+
+ /* Make sure we can rewrite header without failing */
+ if (buffer_len > new_header.header_size * new_header.cluster_size) {
+ return -ENOSPC;
+ }
+
+ /* Prepare new header */
+ buffer = qemu_malloc(buffer_len);
+
+ qed_header_cpu_to_le(&new_header, &le_header);
+ memcpy(buffer, &le_header, sizeof(le_header));
+ buffer_len = sizeof(le_header);
+
+ memcpy(buffer + buffer_len, backing_file, backing_file_len);
+ buffer_len += backing_file_len;
+
+ memcpy(buffer + buffer_len, backing_fmt, backing_fmt_len);
+ buffer_len += backing_fmt_len;
+
+ /* Write new header */
+ ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len);
+ qemu_free(buffer);
+ if (ret == 0) {
+ memcpy(&s->header, &new_header, sizeof(new_header));
+ }
+ return ret;
+}
+
+static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result)
+{
+ return -ENOTSUP;
+}
+
+static QEMUOptionParameter qed_create_options[] = {
+ {
+ .name = BLOCK_OPT_SIZE,
+ .type = OPT_SIZE,
+ .help = "Virtual disk size (in bytes)"
+ }, {
+ .name = BLOCK_OPT_BACKING_FILE,
+ .type = OPT_STRING,
+ .help = "File name of a base image"
+ }, {
+ .name = BLOCK_OPT_BACKING_FMT,
+ .type = OPT_STRING,
+ .help = "Image format of the base image"
+ }, {
+ .name = BLOCK_OPT_CLUSTER_SIZE,
+ .type = OPT_SIZE,
+ .help = "Cluster size (in bytes)"
+ }, {
+ .name = "table_size",
+ .type = OPT_SIZE,
+ .help = "L1/L2 table size (in clusters)"
+ },
+ { /* end of list */ }
+};
+
+static BlockDriver bdrv_qed = {
+ .format_name = "qed",
+ .instance_size = sizeof(BDRVQEDState),
+ .create_options = qed_create_options,
+
+ .bdrv_probe = bdrv_qed_probe,
+ .bdrv_open = bdrv_qed_open,
+ .bdrv_close = bdrv_qed_close,
+ .bdrv_create = bdrv_qed_create,
+ .bdrv_flush = bdrv_qed_flush,
+ .bdrv_is_allocated = bdrv_qed_is_allocated,
+ .bdrv_make_empty = bdrv_qed_make_empty,
+ .bdrv_aio_readv = bdrv_qed_aio_readv,
+ .bdrv_aio_writev = bdrv_qed_aio_writev,
+ .bdrv_aio_flush = bdrv_qed_aio_flush,
+ .bdrv_truncate = bdrv_qed_truncate,
+ .bdrv_getlength = bdrv_qed_getlength,
+ .bdrv_get_info = bdrv_qed_get_info,
+ .bdrv_change_backing_file = bdrv_qed_change_backing_file,
+ .bdrv_check = bdrv_qed_check,
+};
+
+static void bdrv_qed_init(void)
+{
+ bdrv_register(&bdrv_qed);
+}
+
+block_init(bdrv_qed_init);
diff --git a/block/qed.h b/block/qed.h
new file mode 100644
index 0000000..7ce95a7
--- /dev/null
+++ b/block/qed.h
@@ -0,0 +1,148 @@
+/*
+ * QEMU Enhanced Disk Format
+ *
+ * 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.
+ *
+ */
+
+#ifndef BLOCK_QED_H
+#define BLOCK_QED_H
+
+#include "block_int.h"
+
+/* The layout of a QED file is as follows:
+ *
+ * +--------+----------+----------+----------+-----+
+ * | header | L1 table | cluster0 | cluster1 | ... |
+ * +--------+----------+----------+----------+-----+
+ *
+ * There is a 2-level pagetable for cluster allocation:
+ *
+ * +----------+
+ * | L1 table |
+ * +----------+
+ * ,------' | '------.
+ * +----------+ | +----------+
+ * | L2 table | ... | L2 table |
+ * +----------+ +----------+
+ * ,------' | '------.
+ * +----------+ | +----------+
+ * | Data | ... | Data |
+ * +----------+ +----------+
+ *
+ * The L1 table is fixed size and always present. L2 tables are allocated on
+ * demand. The L1 table size determines the maximum possible image size; it
+ * can be influenced using the cluster_size and table_size values.
+ *
+ * All fields are little-endian on disk.
+ */
+
+enum {
+ QED_MAGIC = 'Q' | 'E' << 8 | 'D' << 16 | '\0' << 24,
+
+ /* The image supports a backing file */
+ QED_F_BACKING_FILE = 0x01,
+
+ /* The image has the backing file format */
+ QED_CF_BACKING_FORMAT = 0x01,
+
+ /* Feature bits must be used when the on-disk format changes */
+ QED_FEATURE_MASK = QED_F_BACKING_FILE, /* supported feature
bits */
+ QED_COMPAT_FEATURE_MASK = QED_CF_BACKING_FORMAT, /* supported compat
feature bits */
+
+ /* Data is stored in groups of sectors called clusters. Cluster size must
+ * be large to avoid keeping too much metadata. I/O requests that have
+ * sub-cluster size will require read-modify-write.
+ */
+ QED_MIN_CLUSTER_SIZE = 4 * 1024, /* in bytes */
+ QED_MAX_CLUSTER_SIZE = 64 * 1024 * 1024,
+ QED_DEFAULT_CLUSTER_SIZE = 64 * 1024,
+
+ /* Allocated clusters are tracked using a 2-level pagetable. Table size is
+ * a multiple of clusters so large maximum image sizes can be supported
+ * without jacking up the cluster size too much.
+ */
+ QED_MIN_TABLE_SIZE = 1, /* in clusters */
+ QED_MAX_TABLE_SIZE = 16,
+ QED_DEFAULT_TABLE_SIZE = 4,
+};
+
+typedef struct {
+ uint32_t magic; /* QED\0 */
+
+ uint32_t cluster_size; /* in bytes */
+ uint32_t table_size; /* for L1 and L2 tables, in clusters */
+ uint32_t header_size; /* in clusters */
+
+ uint64_t features; /* format feature bits */
+ uint64_t compat_features; /* compatible feature bits */
+ uint64_t l1_table_offset; /* in bytes */
+ uint64_t image_size; /* total logical image size, in bytes */
+
+ /* if (features & QED_F_BACKING_FILE) */
+ uint32_t backing_filename_offset; /* in bytes from start of header */
+ uint32_t backing_filename_size; /* in bytes */
+
+ /* if (compat_features & QED_CF_BACKING_FORMAT) */
+ uint32_t backing_fmt_offset; /* in bytes from start of header */
+ uint32_t backing_fmt_size; /* in bytes */
+} QEDHeader;
+
+typedef struct {
+ BlockDriverState *bs; /* device */
+ uint64_t file_size; /* length of image file, in bytes */
+
+ QEDHeader header; /* always cpu-endian */
+ uint32_t table_nelems;
+ uint32_t l1_shift;
+ uint32_t l2_shift;
+ uint32_t l2_mask;
+} BDRVQEDState;
+
+/**
+ * Utility functions
+ */
+static inline uint64_t qed_start_of_cluster(BDRVQEDState *s, uint64_t offset)
+{
+ return offset & ~(uint64_t)(s->header.cluster_size - 1);
+}
+
+/**
+ * Test if a cluster offset is valid
+ */
+static inline bool qed_check_cluster_offset(BDRVQEDState *s, uint64_t offset)
+{
+ uint64_t header_size = (uint64_t)s->header.header_size *
+ s->header.cluster_size;
+
+ if (offset & (s->header.cluster_size - 1)) {
+ return false;
+ }
+ return offset >= header_size && offset < s->file_size;
+}
+
+/**
+ * Test if a table offset is valid
+ */
+static inline bool qed_check_table_offset(BDRVQEDState *s, uint64_t offset)
+{
+ uint64_t end_offset = offset + (s->header.table_size - 1) *
+ s->header.cluster_size;
+
+ /* Overflow check */
+ if (end_offset <= offset) {
+ return false;
+ }
+
+ return qed_check_cluster_offset(s, offset) &&
+ qed_check_cluster_offset(s, end_offset);
+}
+
+#endif /* BLOCK_QED_H */
--
1.7.1
- [Qemu-devel] [PATCH 0/7] qed: Add QEMU Enhanced Disk format, Stefan Hajnoczi, 2010/09/23
- [Qemu-devel] [PATCH 3/7] cutils: qemu_iovec_copy and qemu_iovec_memset, Stefan Hajnoczi, 2010/09/23
- [Qemu-devel] [PATCH 7/7] qed: Consistency check support, Stefan Hajnoczi, 2010/09/23
- [Qemu-devel] [PATCH 5/7] qed: Table, L2 cache, and cluster functions, Stefan Hajnoczi, 2010/09/23
- [Qemu-devel] [PATCH 1/7] qcow2: Make get_bits_from_size() common, Stefan Hajnoczi, 2010/09/23
[Qemu-devel] [PATCH 2/7] cutils: Add bytes_to_str() to format byte values, Stefan Hajnoczi, 2010/09/23
[Qemu-devel] [PATCH 4/7] qed: Add QEMU Enhanced Disk image format,
Stefan Hajnoczi <=
[Qemu-devel] [PATCH 6/7] qed: Read/write support, Stefan Hajnoczi, 2010/09/23
Re: [Qemu-devel] [PATCH 0/7] qed: Add QEMU Enhanced Disk format, Avi Kivity, 2010/09/27
Re: [Qemu-devel] [PATCH 0/7] qed: Add QEMU Enhanced Disk format, Avi Kivity, 2010/09/27