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qemu/block/qed.c
Max Reitz 998c201923 block: Add BDS.auto_backing_file 
If the backing file is overridden, this most probably does change the
guest-visible data of a BDS.  Therefore, we will need to consider this
in bdrv_refresh_filename().

To see whether it has been overridden, we might want to compare
bs->backing_file and bs->backing->bs->filename.  However,
bs->backing_file is changed by bdrv_set_backing_hd() (which is just used
to change the backing child at runtime, without modifying the image
header), so bs->backing_file most of the time simply contains a copy of
bs->backing->bs->filename anyway, so it is useless for such a
comparison.

This patch adds an auto_backing_file BDS field which contains the
backing file path as indicated by the image header, which is not changed
by bdrv_set_backing_hd().

Because of bdrv_refresh_filename() magic, however, a BDS's filename may
differ from what has been specified during bdrv_open().  Then, the
comparison between bs->auto_backing_file and bs->backing->bs->filename
may fail even though bs->backing was opened from bs->auto_backing_file.
To mitigate this, we can copy the real BDS's filename (after the whole
bdrv_open() and bdrv_refresh_filename() process) into
bs->auto_backing_file, if we know the former has been opened based on
the latter.  This is only possible if no options modifying the backing
file's behavior have been specified, though.  To simplify things, this
patch only copies the filename from the backing file if no options have
been specified for it at all.

Furthermore, there are cases where an overlay is created by qemu which
already contains a BDS's filename (e.g. in blockdev-snapshot-sync).  We
do not need to worry about updating the overlay's bs->auto_backing_file
there, because we actually wrote a post-bdrv_refresh_filename() filename
into the image header.

So all in all, there will be false negatives where (as of a future
patch) bdrv_refresh_filename() will assume that the backing file differs
from what was specified in the image header, even though it really does
not.  However, these cases should be limited to where (1) the user
actually did override something in the backing chain (e.g. by specifying
options for the backing file), or (2) the user executed a QMP command to
change some node's backing file (e.g. change-backing-file or
block-commit with @backing-file given) where the given filename does not
happen to coincide with qemu's idea of the backing BDS's filename.

Then again, (1) really is limited to -drive.  With -blockdev or
blockdev-add, you have to adhere to the schema, so a user cannot give
partial "unimportant" options (e.g. by just setting backing.node-name
and leaving the rest to the image header).  Therefore, trying to fix
this would mean trying to fix something for -drive only.

To improve on (2), we would need a full infrastructure to "canonicalize"
an arbitrary filename (+ options), so it can be compared against
another.  That seems a bit over the top, considering that filenames
nowadays are there mostly for the user's entertainment.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20190201192935.18394-5-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-02-25 15:11:25 +01:00

1705 lines
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/*
* QEMU Enhanced Disk Format
*
* 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 "qemu/osdep.h"
#include "block/qdict.h"
#include "qapi/error.h"
#include "qemu/timer.h"
#include "qemu/bswap.h"
#include "qemu/option.h"
#include "trace.h"
#include "qed.h"
#include "sysemu/block-backend.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qobject-input-visitor.h"
#include "qapi/qapi-visit-block-core.h"
static QemuOptsList qed_create_opts;
static int bdrv_qed_probe(const uint8_t *buf, int buf_size,
const char *filename)
{
const QEDHeader *header = (const QEDHeader *)buf;
if (buf_size < sizeof(*header)) {
return 0;
}
if (le32_to_cpu(header->magic) != QED_MAGIC) {
return 0;
}
return 100;
}
/**
* Check whether an image format is raw
*
* @fmt: Backing file format, may be NULL
*/
static bool qed_fmt_is_raw(const char *fmt)
{
return fmt && strcmp(fmt, "raw") == 0;
}
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->autoclear_features = le64_to_cpu(le->autoclear_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);
}
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->autoclear_features = cpu_to_le64(cpu->autoclear_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);
}
int qed_write_header_sync(BDRVQEDState *s)
{
QEDHeader le;
int ret;
qed_header_cpu_to_le(&s->header, &le);
ret = bdrv_pwrite(s->bs->file, 0, &le, sizeof(le));
if (ret != sizeof(le)) {
return ret;
}
return 0;
}
/**
* Update header in-place (does not rewrite backing filename or other strings)
*
* This function only updates known header fields in-place and does not affect
* extra data after the QED header.
*
* No new allocating reqs can start while this function runs.
*/
static int coroutine_fn qed_write_header(BDRVQEDState *s)
{
/* We must write full sectors for O_DIRECT but cannot necessarily generate
* the data following the header if an unrecognized compat feature is
* active. Therefore, first read the sectors containing the header, update
* them, and write back.
*/
int nsectors = DIV_ROUND_UP(sizeof(QEDHeader), BDRV_SECTOR_SIZE);
size_t len = nsectors * BDRV_SECTOR_SIZE;
uint8_t *buf;
struct iovec iov;
QEMUIOVector qiov;
int ret;
assert(s->allocating_acb || s->allocating_write_reqs_plugged);
buf = qemu_blockalign(s->bs, len);
iov = (struct iovec) {
.iov_base = buf,
.iov_len = len,
};
qemu_iovec_init_external(&qiov, &iov, 1);
ret = bdrv_co_preadv(s->bs->file, 0, qiov.size, &qiov, 0);
if (ret < 0) {
goto out;
}
/* Update header */
qed_header_cpu_to_le(&s->header, (QEDHeader *) buf);
ret = bdrv_co_pwritev(s->bs->file, 0, qiov.size, &qiov, 0);
if (ret < 0) {
goto out;
}
ret = 0;
out:
qemu_vfree(buf);
return ret;
}
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 % BDRV_SECTOR_SIZE != 0) {
return false; /* not multiple of sector 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
* @ret: 0 on success, -errno on failure
*
* The string is NUL-terminated.
*/
static int qed_read_string(BdrvChild *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 < 0) {
return ret;
}
buf[n] = '\0';
return 0;
}
/**
* Allocate new clusters
*
* @s: QED state
* @n: Number of contiguous clusters to allocate
* @ret: Offset of first allocated cluster
*
* This function only produces the offset where the new clusters should be
* written. It updates BDRVQEDState but does not make any changes to the image
* file.
*
* Called with table_lock held.
*/
static uint64_t qed_alloc_clusters(BDRVQEDState *s, unsigned int n)
{
uint64_t offset = s->file_size;
s->file_size += n * s->header.cluster_size;
return offset;
}
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);
}
/**
* Allocate a new zeroed L2 table
*
* Called with table_lock held.
*/
static CachedL2Table *qed_new_l2_table(BDRVQEDState *s)
{
CachedL2Table *l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
l2_table->table = qed_alloc_table(s);
l2_table->offset = qed_alloc_clusters(s, s->header.table_size);
memset(l2_table->table->offsets, 0,
s->header.cluster_size * s->header.table_size);
return l2_table;
}
static bool qed_plug_allocating_write_reqs(BDRVQEDState *s)
{
qemu_co_mutex_lock(&s->table_lock);
/* No reentrancy is allowed. */
assert(!s->allocating_write_reqs_plugged);
if (s->allocating_acb != NULL) {
/* Another allocating write came concurrently. This cannot happen
* from bdrv_qed_co_drain_begin, but it can happen when the timer runs.
*/
qemu_co_mutex_unlock(&s->table_lock);
return false;
}
s->allocating_write_reqs_plugged = true;
qemu_co_mutex_unlock(&s->table_lock);
return true;
}
static void qed_unplug_allocating_write_reqs(BDRVQEDState *s)
{
qemu_co_mutex_lock(&s->table_lock);
assert(s->allocating_write_reqs_plugged);
s->allocating_write_reqs_plugged = false;
qemu_co_queue_next(&s->allocating_write_reqs);
qemu_co_mutex_unlock(&s->table_lock);
}
static void coroutine_fn qed_need_check_timer_entry(void *opaque)
{
BDRVQEDState *s = opaque;
int ret;
trace_qed_need_check_timer_cb(s);
if (!qed_plug_allocating_write_reqs(s)) {
return;
}
/* Ensure writes are on disk before clearing flag */
ret = bdrv_co_flush(s->bs->file->bs);
if (ret < 0) {
qed_unplug_allocating_write_reqs(s);
return;
}
s->header.features &= ~QED_F_NEED_CHECK;
ret = qed_write_header(s);
(void) ret;
qed_unplug_allocating_write_reqs(s);
ret = bdrv_co_flush(s->bs);
(void) ret;
}
static void qed_need_check_timer_cb(void *opaque)
{
Coroutine *co = qemu_coroutine_create(qed_need_check_timer_entry, opaque);
qemu_coroutine_enter(co);
}
static void qed_start_need_check_timer(BDRVQEDState *s)
{
trace_qed_start_need_check_timer(s);
/* Use QEMU_CLOCK_VIRTUAL so we don't alter the image file while suspended for
* migration.
*/
timer_mod(s->need_check_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
NANOSECONDS_PER_SECOND * QED_NEED_CHECK_TIMEOUT);
}
/* It's okay to call this multiple times or when no timer is started */
static void qed_cancel_need_check_timer(BDRVQEDState *s)
{
trace_qed_cancel_need_check_timer(s);
timer_del(s->need_check_timer);
}
static void bdrv_qed_detach_aio_context(BlockDriverState *bs)
{
BDRVQEDState *s = bs->opaque;
qed_cancel_need_check_timer(s);
timer_free(s->need_check_timer);
}
static void bdrv_qed_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
BDRVQEDState *s = bs->opaque;
s->need_check_timer = aio_timer_new(new_context,
QEMU_CLOCK_VIRTUAL, SCALE_NS,
qed_need_check_timer_cb, s);
if (s->header.features & QED_F_NEED_CHECK) {
qed_start_need_check_timer(s);
}
}
static void coroutine_fn bdrv_qed_co_drain_begin(BlockDriverState *bs)
{
BDRVQEDState *s = bs->opaque;
/* Fire the timer immediately in order to start doing I/O as soon as the
* header is flushed.
*/
if (s->need_check_timer && timer_pending(s->need_check_timer)) {
qed_cancel_need_check_timer(s);
qed_need_check_timer_entry(s);
}
}
static void bdrv_qed_init_state(BlockDriverState *bs)
{
BDRVQEDState *s = bs->opaque;
memset(s, 0, sizeof(BDRVQEDState));
s->bs = bs;
qemu_co_mutex_init(&s->table_lock);
qemu_co_queue_init(&s->allocating_write_reqs);
}
/* Called with table_lock held. */
static int coroutine_fn bdrv_qed_do_open(BlockDriverState *bs, QDict *options,
int flags, Error **errp)
{
BDRVQEDState *s = bs->opaque;
QEDHeader le_header;
int64_t file_size;
int ret;
ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header));
if (ret < 0) {
return ret;
}
qed_header_le_to_cpu(&le_header, &s->header);
if (s->header.magic != QED_MAGIC) {
error_setg(errp, "Image not in QED format");
return -EINVAL;
}
if (s->header.features & ~QED_FEATURE_MASK) {
/* image uses unsupported feature bits */
error_setg(errp, "Unsupported QED features: %" PRIx64,
s->header.features & ~QED_FEATURE_MASK);
return -ENOTSUP;
}
if (!qed_is_cluster_size_valid(s->header.cluster_size)) {
return -EINVAL;
}
/* Round down file size to the last cluster */
file_size = bdrv_getlength(bs->file->bs);
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 = ctz32(s->header.cluster_size);
s->l2_mask = s->table_nelems - 1;
s->l1_shift = s->l2_shift + ctz32(s->table_nelems);
/* Header size calculation must not overflow uint32_t */
if (s->header.header_size > UINT32_MAX / s->header.cluster_size) {
return -EINVAL;
}
if ((s->header.features & QED_F_BACKING_FILE)) {
if ((uint64_t)s->header.backing_filename_offset +
s->header.backing_filename_size >
s->header.cluster_size * s->header.header_size) {
return -EINVAL;
}
ret = qed_read_string(bs->file, s->header.backing_filename_offset,
s->header.backing_filename_size,
bs->auto_backing_file,
sizeof(bs->auto_backing_file));
if (ret < 0) {
return ret;
}
pstrcpy(bs->backing_file, sizeof(bs->backing_file),
bs->auto_backing_file);
if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) {
pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw");
}
}
/* Reset unknown autoclear feature bits. This is a backwards
* compatibility mechanism that allows images to be opened by older
* programs, which "knock out" unknown feature bits. When an image is
* opened by a newer program again it can detect that the autoclear
* feature is no longer valid.
*/
if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 &&
!bdrv_is_read_only(bs->file->bs) && !(flags & BDRV_O_INACTIVE)) {
s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK;
ret = qed_write_header_sync(s);
if (ret) {
return ret;
}
/* From here on only known autoclear feature bits are valid */
bdrv_flush(bs->file->bs);
}
s->l1_table = qed_alloc_table(s);
qed_init_l2_cache(&s->l2_cache);
ret = qed_read_l1_table_sync(s);
if (ret) {
goto out;
}
/* If image was not closed cleanly, check consistency */
if (!(flags & BDRV_O_CHECK) && (s->header.features & QED_F_NEED_CHECK)) {
/* Read-only images cannot be fixed. There is no risk of corruption
* since write operations are not possible. Therefore, allow
* potentially inconsistent images to be opened read-only. This can
* aid data recovery from an otherwise inconsistent image.
*/
if (!bdrv_is_read_only(bs->file->bs) &&
!(flags & BDRV_O_INACTIVE)) {
BdrvCheckResult result = {0};
ret = qed_check(s, &result, true);
if (ret) {
goto out;
}
}
}
bdrv_qed_attach_aio_context(bs, bdrv_get_aio_context(bs));
out:
if (ret) {
qed_free_l2_cache(&s->l2_cache);
qemu_vfree(s->l1_table);
}
return ret;
}
typedef struct QEDOpenCo {
BlockDriverState *bs;
QDict *options;
int flags;
Error **errp;
int ret;
} QEDOpenCo;
static void coroutine_fn bdrv_qed_open_entry(void *opaque)
{
QEDOpenCo *qoc = opaque;
BDRVQEDState *s = qoc->bs->opaque;
qemu_co_mutex_lock(&s->table_lock);
qoc->ret = bdrv_qed_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp);
qemu_co_mutex_unlock(&s->table_lock);
}
static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
QEDOpenCo qoc = {
.bs = bs,
.options = options,
.flags = flags,
.errp = errp,
.ret = -EINPROGRESS
};
bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
false, errp);
if (!bs->file) {
return -EINVAL;
}
bdrv_qed_init_state(bs);
if (qemu_in_coroutine()) {
bdrv_qed_open_entry(&qoc);
} else {
assert(qemu_get_current_aio_context() == qemu_get_aio_context());
qemu_coroutine_enter(qemu_coroutine_create(bdrv_qed_open_entry, &qoc));
BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS);
}
BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS);
return qoc.ret;
}
static void bdrv_qed_refresh_limits(BlockDriverState *bs, Error **errp)
{
BDRVQEDState *s = bs->opaque;
bs->bl.pwrite_zeroes_alignment = s->header.cluster_size;
}
/* We have nothing to do for QED reopen, stubs just return
* success */
static int bdrv_qed_reopen_prepare(BDRVReopenState *state,
BlockReopenQueue *queue, Error **errp)
{
return 0;
}
static void bdrv_qed_close(BlockDriverState *bs)
{
BDRVQEDState *s = bs->opaque;
bdrv_qed_detach_aio_context(bs);
/* Ensure writes reach stable storage */
bdrv_flush(bs->file->bs);
/* Clean shutdown, no check required on next open */
if (s->header.features & QED_F_NEED_CHECK) {
s->header.features &= ~QED_F_NEED_CHECK;
qed_write_header_sync(s);
}
qed_free_l2_cache(&s->l2_cache);
qemu_vfree(s->l1_table);
}
static int coroutine_fn bdrv_qed_co_create(BlockdevCreateOptions *opts,
Error **errp)
{
BlockdevCreateOptionsQed *qed_opts;
BlockBackend *blk = NULL;
BlockDriverState *bs = NULL;
QEDHeader header;
QEDHeader le_header;
uint8_t *l1_table = NULL;
size_t l1_size;
int ret = 0;
assert(opts->driver == BLOCKDEV_DRIVER_QED);
qed_opts = &opts->u.qed;
/* Validate options and set default values */
if (!qed_opts->has_cluster_size) {
qed_opts->cluster_size = QED_DEFAULT_CLUSTER_SIZE;
}
if (!qed_opts->has_table_size) {
qed_opts->table_size = QED_DEFAULT_TABLE_SIZE;
}
if (!qed_is_cluster_size_valid(qed_opts->cluster_size)) {
error_setg(errp, "QED cluster size must be within range [%u, %u] "
"and power of 2",
QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE);
return -EINVAL;
}
if (!qed_is_table_size_valid(qed_opts->table_size)) {
error_setg(errp, "QED table size must be within range [%u, %u] "
"and power of 2",
QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE);
return -EINVAL;
}
if (!qed_is_image_size_valid(qed_opts->size, qed_opts->cluster_size,
qed_opts->table_size))
{
error_setg(errp, "QED image size must be a non-zero multiple of "
"cluster size and less than %" PRIu64 " bytes",
qed_max_image_size(qed_opts->cluster_size,
qed_opts->table_size));
return -EINVAL;
}
/* Create BlockBackend to write to the image */
bs = bdrv_open_blockdev_ref(qed_opts->file, errp);
if (bs == NULL) {
return -EIO;
}
blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
ret = blk_insert_bs(blk, bs, errp);
if (ret < 0) {
goto out;
}
blk_set_allow_write_beyond_eof(blk, true);
/* Prepare image format */
header = (QEDHeader) {
.magic = QED_MAGIC,
.cluster_size = qed_opts->cluster_size,
.table_size = qed_opts->table_size,
.header_size = 1,
.features = 0,
.compat_features = 0,
.l1_table_offset = qed_opts->cluster_size,
.image_size = qed_opts->size,
};
l1_size = header.cluster_size * header.table_size;
/* File must start empty and grow, check truncate is supported */
ret = blk_truncate(blk, 0, PREALLOC_MODE_OFF, errp);
if (ret < 0) {
goto out;
}
if (qed_opts->has_backing_file) {
header.features |= QED_F_BACKING_FILE;
header.backing_filename_offset = sizeof(le_header);
header.backing_filename_size = strlen(qed_opts->backing_file);
if (qed_opts->has_backing_fmt) {
const char *backing_fmt = BlockdevDriver_str(qed_opts->backing_fmt);
if (qed_fmt_is_raw(backing_fmt)) {
header.features |= QED_F_BACKING_FORMAT_NO_PROBE;
}
}
}
qed_header_cpu_to_le(&header, &le_header);
ret = blk_pwrite(blk, 0, &le_header, sizeof(le_header), 0);
if (ret < 0) {
goto out;
}
ret = blk_pwrite(blk, sizeof(le_header), qed_opts->backing_file,
header.backing_filename_size, 0);
if (ret < 0) {
goto out;
}
l1_table = g_malloc0(l1_size);
ret = blk_pwrite(blk, header.l1_table_offset, l1_table, l1_size, 0);
if (ret < 0) {
goto out;
}
ret = 0; /* success */
out:
g_free(l1_table);
blk_unref(blk);
bdrv_unref(bs);
return ret;
}
static int coroutine_fn bdrv_qed_co_create_opts(const char *filename,
QemuOpts *opts,
Error **errp)
{
BlockdevCreateOptions *create_options = NULL;
QDict *qdict;
Visitor *v;
BlockDriverState *bs = NULL;
Error *local_err = NULL;
int ret;
static const QDictRenames opt_renames[] = {
{ BLOCK_OPT_BACKING_FILE, "backing-file" },
{ BLOCK_OPT_BACKING_FMT, "backing-fmt" },
{ BLOCK_OPT_CLUSTER_SIZE, "cluster-size" },
{ BLOCK_OPT_TABLE_SIZE, "table-size" },
{ NULL, NULL },
};
/* Parse options and convert legacy syntax */
qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qed_create_opts, true);
if (!qdict_rename_keys(qdict, opt_renames, errp)) {
ret = -EINVAL;
goto fail;
}
/* Create and open the file (protocol layer) */
ret = bdrv_create_file(filename, opts, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
goto fail;
}
bs = bdrv_open(filename, NULL, NULL,
BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
if (bs == NULL) {
ret = -EIO;
goto fail;
}
/* Now get the QAPI type BlockdevCreateOptions */
qdict_put_str(qdict, "driver", "qed");
qdict_put_str(qdict, "file", bs->node_name);
v = qobject_input_visitor_new_flat_confused(qdict, errp);
if (!v) {
ret = -EINVAL;
goto fail;
}
visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err);
visit_free(v);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
/* Silently round up size */
assert(create_options->driver == BLOCKDEV_DRIVER_QED);
create_options->u.qed.size =
ROUND_UP(create_options->u.qed.size, BDRV_SECTOR_SIZE);
/* Create the qed image (format layer) */
ret = bdrv_qed_co_create(create_options, errp);
fail:
qobject_unref(qdict);
bdrv_unref(bs);
qapi_free_BlockdevCreateOptions(create_options);
return ret;
}
static int coroutine_fn bdrv_qed_co_block_status(BlockDriverState *bs,
bool want_zero,
int64_t pos, int64_t bytes,
int64_t *pnum, int64_t *map,
BlockDriverState **file)
{
BDRVQEDState *s = bs->opaque;
size_t len = MIN(bytes, SIZE_MAX);
int status;
QEDRequest request = { .l2_table = NULL };
uint64_t offset;
int ret;
qemu_co_mutex_lock(&s->table_lock);
ret = qed_find_cluster(s, &request, pos, &len, &offset);
*pnum = len;
switch (ret) {
case QED_CLUSTER_FOUND:
*map = offset | qed_offset_into_cluster(s, pos);
status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
*file = bs->file->bs;
break;
case QED_CLUSTER_ZERO:
status = BDRV_BLOCK_ZERO;
break;
case QED_CLUSTER_L2:
case QED_CLUSTER_L1:
status = 0;
break;
default:
assert(ret < 0);
status = ret;
break;
}
qed_unref_l2_cache_entry(request.l2_table);
qemu_co_mutex_unlock(&s->table_lock);
return status;
}
static BDRVQEDState *acb_to_s(QEDAIOCB *acb)
{
return acb->bs->opaque;
}
/**
* Read from the backing file or zero-fill if no backing file
*
* @s: QED state
* @pos: Byte position in device
* @qiov: Destination I/O vector
* @backing_qiov: Possibly shortened copy of qiov, to be allocated here
* @cb: Completion function
* @opaque: User data for completion function
*
* This function reads qiov->size bytes starting at pos from the backing file.
* If there is no backing file then zeroes are read.
*/
static int coroutine_fn qed_read_backing_file(BDRVQEDState *s, uint64_t pos,
QEMUIOVector *qiov,
QEMUIOVector **backing_qiov)
{
uint64_t backing_length = 0;
size_t size;
int ret;
/* If there is a backing file, get its length. Treat the absence of a
* backing file like a zero length backing file.
*/
if (s->bs->backing) {
int64_t l = bdrv_getlength(s->bs->backing->bs);
if (l < 0) {
return l;
}
backing_length = l;
}
/* Zero all sectors if reading beyond the end of the backing file */
if (pos >= backing_length ||
pos + qiov->size > backing_length) {
qemu_iovec_memset(qiov, 0, 0, qiov->size);
}
/* Complete now if there are no backing file sectors to read */
if (pos >= backing_length) {
return 0;
}
/* If the read straddles the end of the backing file, shorten it */
size = MIN((uint64_t)backing_length - pos, qiov->size);
assert(*backing_qiov == NULL);
*backing_qiov = g_new(QEMUIOVector, 1);
qemu_iovec_init(*backing_qiov, qiov->niov);
qemu_iovec_concat(*backing_qiov, qiov, 0, size);
BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO);
ret = bdrv_co_preadv(s->bs->backing, pos, size, *backing_qiov, 0);
if (ret < 0) {
return ret;
}
return 0;
}
/**
* Copy data from backing file into the image
*
* @s: QED state
* @pos: Byte position in device
* @len: Number of bytes
* @offset: Byte offset in image file
*/
static int coroutine_fn qed_copy_from_backing_file(BDRVQEDState *s,
uint64_t pos, uint64_t len,
uint64_t offset)
{
QEMUIOVector qiov;
QEMUIOVector *backing_qiov = NULL;
struct iovec iov;
int ret;
/* Skip copy entirely if there is no work to do */
if (len == 0) {
return 0;
}
iov = (struct iovec) {
.iov_base = qemu_blockalign(s->bs, len),
.iov_len = len,
};
qemu_iovec_init_external(&qiov, &iov, 1);
ret = qed_read_backing_file(s, pos, &qiov, &backing_qiov);
if (backing_qiov) {
qemu_iovec_destroy(backing_qiov);
g_free(backing_qiov);
backing_qiov = NULL;
}
if (ret) {
goto out;
}
BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE);
ret = bdrv_co_pwritev(s->bs->file, offset, qiov.size, &qiov, 0);
if (ret < 0) {
goto out;
}
ret = 0;
out:
qemu_vfree(iov.iov_base);
return ret;
}
/**
* Link one or more contiguous clusters into a table
*
* @s: QED state
* @table: L2 table
* @index: First cluster index
* @n: Number of contiguous clusters
* @cluster: First cluster offset
*
* The cluster offset may be an allocated byte offset in the image file, the
* zero cluster marker, or the unallocated cluster marker.
*
* Called with table_lock held.
*/
static void coroutine_fn qed_update_l2_table(BDRVQEDState *s, QEDTable *table,
int index, unsigned int n,
uint64_t cluster)
{
int i;
for (i = index; i < index + n; i++) {
table->offsets[i] = cluster;
if (!qed_offset_is_unalloc_cluster(cluster) &&
!qed_offset_is_zero_cluster(cluster)) {
cluster += s->header.cluster_size;
}
}
}
/* Called with table_lock held. */
static void coroutine_fn qed_aio_complete(QEDAIOCB *acb)
{
BDRVQEDState *s = acb_to_s(acb);
/* Free resources */
qemu_iovec_destroy(&acb->cur_qiov);
qed_unref_l2_cache_entry(acb->request.l2_table);
/* Free the buffer we may have allocated for zero writes */
if (acb->flags & QED_AIOCB_ZERO) {
qemu_vfree(acb->qiov->iov[0].iov_base);
acb->qiov->iov[0].iov_base = NULL;
}
/* Start next allocating write request waiting behind this one. Note that
* requests enqueue themselves when they first hit an unallocated cluster
* but they wait until the entire request is finished before waking up the
* next request in the queue. This ensures that we don't cycle through
* requests multiple times but rather finish one at a time completely.
*/
if (acb == s->allocating_acb) {
s->allocating_acb = NULL;
if (!qemu_co_queue_empty(&s->allocating_write_reqs)) {
qemu_co_queue_next(&s->allocating_write_reqs);
} else if (s->header.features & QED_F_NEED_CHECK) {
qed_start_need_check_timer(s);
}
}
}
/**
* Update L1 table with new L2 table offset and write it out
*
* Called with table_lock held.
*/
static int coroutine_fn qed_aio_write_l1_update(QEDAIOCB *acb)
{
BDRVQEDState *s = acb_to_s(acb);
CachedL2Table *l2_table = acb->request.l2_table;
uint64_t l2_offset = l2_table->offset;
int index, ret;
index = qed_l1_index(s, acb->cur_pos);
s->l1_table->offsets[index] = l2_table->offset;
ret = qed_write_l1_table(s, index, 1);
/* Commit the current L2 table to the cache */
qed_commit_l2_cache_entry(&s->l2_cache, l2_table);
/* This is guaranteed to succeed because we just committed the entry to the
* cache.
*/
acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset);
assert(acb->request.l2_table != NULL);
return ret;
}
/**
* Update L2 table with new cluster offsets and write them out
*
* Called with table_lock held.
*/
static int coroutine_fn qed_aio_write_l2_update(QEDAIOCB *acb, uint64_t offset)
{
BDRVQEDState *s = acb_to_s(acb);
bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1;
int index, ret;
if (need_alloc) {
qed_unref_l2_cache_entry(acb->request.l2_table);
acb->request.l2_table = qed_new_l2_table(s);
}
index = qed_l2_index(s, acb->cur_pos);
qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters,
offset);
if (need_alloc) {
/* Write out the whole new L2 table */
ret = qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true);
if (ret) {
return ret;
}
return qed_aio_write_l1_update(acb);
} else {
/* Write out only the updated part of the L2 table */
ret = qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters,
false);
if (ret) {
return ret;
}
}
return 0;
}
/**
* Write data to the image file
*
* Called with table_lock *not* held.
*/
static int coroutine_fn qed_aio_write_main(QEDAIOCB *acb)
{
BDRVQEDState *s = acb_to_s(acb);
uint64_t offset = acb->cur_cluster +
qed_offset_into_cluster(s, acb->cur_pos);
trace_qed_aio_write_main(s, acb, 0, offset, acb->cur_qiov.size);
BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO);
return bdrv_co_pwritev(s->bs->file, offset, acb->cur_qiov.size,
&acb->cur_qiov, 0);
}
/**
* Populate untouched regions of new data cluster
*
* Called with table_lock held.
*/
static int coroutine_fn qed_aio_write_cow(QEDAIOCB *acb)
{
BDRVQEDState *s = acb_to_s(acb);
uint64_t start, len, offset;
int ret;
qemu_co_mutex_unlock(&s->table_lock);
/* Populate front untouched region of new data cluster */
start = qed_start_of_cluster(s, acb->cur_pos);
len = qed_offset_into_cluster(s, acb->cur_pos);
trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster);
ret = qed_copy_from_backing_file(s, start, len, acb->cur_cluster);
if (ret < 0) {
goto out;
}
/* Populate back untouched region of new data cluster */
start = acb->cur_pos + acb->cur_qiov.size;
len = qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start;
offset = acb->cur_cluster +
qed_offset_into_cluster(s, acb->cur_pos) +
acb->cur_qiov.size;
trace_qed_aio_write_postfill(s, acb, start, len, offset);
ret = qed_copy_from_backing_file(s, start, len, offset);
if (ret < 0) {
goto out;
}
ret = qed_aio_write_main(acb);
if (ret < 0) {
goto out;
}
if (s->bs->backing) {
/*
* Flush new data clusters before updating the L2 table
*
* This flush is necessary when a backing file is in use. A crash
* during an allocating write could result in empty clusters in the
* image. If the write only touched a subregion of the cluster,
* then backing image sectors have been lost in the untouched
* region. The solution is to flush after writing a new data
* cluster and before updating the L2 table.
*/
ret = bdrv_co_flush(s->bs->file->bs);
}
out:
qemu_co_mutex_lock(&s->table_lock);
return ret;
}
/**
* Check if the QED_F_NEED_CHECK bit should be set during allocating write
*/
static bool qed_should_set_need_check(BDRVQEDState *s)
{
/* The flush before L2 update path ensures consistency */
if (s->bs->backing) {
return false;
}
return !(s->header.features & QED_F_NEED_CHECK);
}
/**
* Write new data cluster
*
* @acb: Write request
* @len: Length in bytes
*
* This path is taken when writing to previously unallocated clusters.
*
* Called with table_lock held.
*/
static int coroutine_fn qed_aio_write_alloc(QEDAIOCB *acb, size_t len)
{
BDRVQEDState *s = acb_to_s(acb);
int ret;
/* Cancel timer when the first allocating request comes in */
if (s->allocating_acb == NULL) {
qed_cancel_need_check_timer(s);
}
/* Freeze this request if another allocating write is in progress */
if (s->allocating_acb != acb || s->allocating_write_reqs_plugged) {
if (s->allocating_acb != NULL) {
qemu_co_queue_wait(&s->allocating_write_reqs, &s->table_lock);
assert(s->allocating_acb == NULL);
}
s->allocating_acb = acb;
return -EAGAIN; /* start over with looking up table entries */
}
acb->cur_nclusters = qed_bytes_to_clusters(s,
qed_offset_into_cluster(s, acb->cur_pos) + len);
qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
if (acb->flags & QED_AIOCB_ZERO) {
/* Skip ahead if the clusters are already zero */
if (acb->find_cluster_ret == QED_CLUSTER_ZERO) {
return 0;
}
acb->cur_cluster = 1;
} else {
acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters);
}
if (qed_should_set_need_check(s)) {
s->header.features |= QED_F_NEED_CHECK;
ret = qed_write_header(s);
if (ret < 0) {
return ret;
}
}
if (!(acb->flags & QED_AIOCB_ZERO)) {
ret = qed_aio_write_cow(acb);
if (ret < 0) {
return ret;
}
}
return qed_aio_write_l2_update(acb, acb->cur_cluster);
}
/**
* Write data cluster in place
*
* @acb: Write request
* @offset: Cluster offset in bytes
* @len: Length in bytes
*
* This path is taken when writing to already allocated clusters.
*
* Called with table_lock held.
*/
static int coroutine_fn qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset,
size_t len)
{
BDRVQEDState *s = acb_to_s(acb);
int r;
qemu_co_mutex_unlock(&s->table_lock);
/* Allocate buffer for zero writes */
if (acb->flags & QED_AIOCB_ZERO) {
struct iovec *iov = acb->qiov->iov;
if (!iov->iov_base) {
iov->iov_base = qemu_try_blockalign(acb->bs, iov->iov_len);
if (iov->iov_base == NULL) {
r = -ENOMEM;
goto out;
}
memset(iov->iov_base, 0, iov->iov_len);
}
}
/* Calculate the I/O vector */
acb->cur_cluster = offset;
qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
/* Do the actual write. */
r = qed_aio_write_main(acb);
out:
qemu_co_mutex_lock(&s->table_lock);
return r;
}
/**
* Write data cluster
*
* @opaque: Write request
* @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2 or QED_CLUSTER_L1
* @offset: Cluster offset in bytes
* @len: Length in bytes
*
* Called with table_lock held.
*/
static int coroutine_fn qed_aio_write_data(void *opaque, int ret,
uint64_t offset, size_t len)
{
QEDAIOCB *acb = opaque;
trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len);
acb->find_cluster_ret = ret;
switch (ret) {
case QED_CLUSTER_FOUND:
return qed_aio_write_inplace(acb, offset, len);
case QED_CLUSTER_L2:
case QED_CLUSTER_L1:
case QED_CLUSTER_ZERO:
return qed_aio_write_alloc(acb, len);
default:
g_assert_not_reached();
}
}
/**
* Read data cluster
*
* @opaque: Read request
* @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2 or QED_CLUSTER_L1
* @offset: Cluster offset in bytes
* @len: Length in bytes
*
* Called with table_lock held.
*/
static int coroutine_fn qed_aio_read_data(void *opaque, int ret,
uint64_t offset, size_t len)
{
QEDAIOCB *acb = opaque;
BDRVQEDState *s = acb_to_s(acb);
BlockDriverState *bs = acb->bs;
int r;
qemu_co_mutex_unlock(&s->table_lock);
/* Adjust offset into cluster */
offset += qed_offset_into_cluster(s, acb->cur_pos);
trace_qed_aio_read_data(s, acb, ret, offset, len);
qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
/* Handle zero cluster and backing file reads, otherwise read
* data cluster directly.
*/
if (ret == QED_CLUSTER_ZERO) {
qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size);
r = 0;
} else if (ret != QED_CLUSTER_FOUND) {
r = qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov,
&acb->backing_qiov);
} else {
BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
r = bdrv_co_preadv(bs->file, offset, acb->cur_qiov.size,
&acb->cur_qiov, 0);
}
qemu_co_mutex_lock(&s->table_lock);
return r;
}
/**
* Begin next I/O or complete the request
*/
static int coroutine_fn qed_aio_next_io(QEDAIOCB *acb)
{
BDRVQEDState *s = acb_to_s(acb);
uint64_t offset;
size_t len;
int ret;
qemu_co_mutex_lock(&s->table_lock);
while (1) {
trace_qed_aio_next_io(s, acb, 0, acb->cur_pos + acb->cur_qiov.size);
if (acb->backing_qiov) {
qemu_iovec_destroy(acb->backing_qiov);
g_free(acb->backing_qiov);
acb->backing_qiov = NULL;
}
acb->qiov_offset += acb->cur_qiov.size;
acb->cur_pos += acb->cur_qiov.size;
qemu_iovec_reset(&acb->cur_qiov);
/* Complete request */
if (acb->cur_pos >= acb->end_pos) {
ret = 0;
break;
}
/* Find next cluster and start I/O */
len = acb->end_pos - acb->cur_pos;
ret = qed_find_cluster(s, &acb->request, acb->cur_pos, &len, &offset);
if (ret < 0) {
break;
}
if (acb->flags & QED_AIOCB_WRITE) {
ret = qed_aio_write_data(acb, ret, offset, len);
} else {
ret = qed_aio_read_data(acb, ret, offset, len);
}
if (ret < 0 && ret != -EAGAIN) {
break;
}
}
trace_qed_aio_complete(s, acb, ret);
qed_aio_complete(acb);
qemu_co_mutex_unlock(&s->table_lock);
return ret;
}
static int coroutine_fn qed_co_request(BlockDriverState *bs, int64_t sector_num,
QEMUIOVector *qiov, int nb_sectors,
int flags)
{
QEDAIOCB acb = {
.bs = bs,
.cur_pos = (uint64_t) sector_num * BDRV_SECTOR_SIZE,
.end_pos = (sector_num + nb_sectors) * BDRV_SECTOR_SIZE,
.qiov = qiov,
.flags = flags,
};
qemu_iovec_init(&acb.cur_qiov, qiov->niov);
trace_qed_aio_setup(bs->opaque, &acb, sector_num, nb_sectors, NULL, flags);
/* Start request */
return qed_aio_next_io(&acb);
}
static int coroutine_fn bdrv_qed_co_readv(BlockDriverState *bs,
int64_t sector_num, int nb_sectors,
QEMUIOVector *qiov)
{
return qed_co_request(bs, sector_num, qiov, nb_sectors, 0);
}
static int coroutine_fn bdrv_qed_co_writev(BlockDriverState *bs,
int64_t sector_num, int nb_sectors,
QEMUIOVector *qiov, int flags)
{
assert(!flags);
return qed_co_request(bs, sector_num, qiov, nb_sectors, QED_AIOCB_WRITE);
}
static int coroutine_fn bdrv_qed_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset,
int bytes,
BdrvRequestFlags flags)
{
BDRVQEDState *s = bs->opaque;
QEMUIOVector qiov;
struct iovec iov;
/* Fall back if the request is not aligned */
if (qed_offset_into_cluster(s, offset) ||
qed_offset_into_cluster(s, bytes)) {
return -ENOTSUP;
}
/* Zero writes start without an I/O buffer. If a buffer becomes necessary
* then it will be allocated during request processing.
*/
iov.iov_base = NULL;
iov.iov_len = bytes;
qemu_iovec_init_external(&qiov, &iov, 1);
return qed_co_request(bs, offset >> BDRV_SECTOR_BITS, &qiov,
bytes >> BDRV_SECTOR_BITS,
QED_AIOCB_WRITE | QED_AIOCB_ZERO);
}
static int coroutine_fn bdrv_qed_co_truncate(BlockDriverState *bs,
int64_t offset,
PreallocMode prealloc,
Error **errp)
{
BDRVQEDState *s = bs->opaque;
uint64_t old_image_size;
int ret;
if (prealloc != PREALLOC_MODE_OFF) {
error_setg(errp, "Unsupported preallocation mode '%s'",
PreallocMode_str(prealloc));
return -ENOTSUP;
}
if (!qed_is_image_size_valid(offset, s->header.cluster_size,
s->header.table_size)) {
error_setg(errp, "Invalid image size specified");
return -EINVAL;
}
if ((uint64_t)offset < s->header.image_size) {
error_setg(errp, "Shrinking images is currently not supported");
return -ENOTSUP;
}
old_image_size = s->header.image_size;
s->header.image_size = offset;
ret = qed_write_header_sync(s);
if (ret < 0) {
s->header.image_size = old_image_size;
error_setg_errno(errp, -ret, "Failed to update the image size");
}
return ret;
}
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;
bdi->is_dirty = s->header.features & QED_F_NEED_CHECK;
bdi->unallocated_blocks_are_zero = true;
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;
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 |
QED_F_BACKING_FORMAT_NO_PROBE);
/* Adjust feature flags */
if (backing_file) {
new_header.features |= QED_F_BACKING_FILE;
if (qed_fmt_is_raw(backing_fmt)) {
new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE;
}
}
/* Calculate new header size */
backing_file_len = 0;
if (backing_file) {
backing_file_len = strlen(backing_file);
}
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;
/* 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 = g_malloc(buffer_len);
qed_header_cpu_to_le(&new_header, &le_header);
memcpy(buffer, &le_header, sizeof(le_header));
buffer_len = sizeof(le_header);
if (backing_file) {
memcpy(buffer + buffer_len, backing_file, backing_file_len);
buffer_len += backing_file_len;
}
/* Write new header */
ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len);
g_free(buffer);
if (ret == 0) {
memcpy(&s->header, &new_header, sizeof(new_header));
}
return ret;
}
static void coroutine_fn bdrv_qed_co_invalidate_cache(BlockDriverState *bs,
Error **errp)
{
BDRVQEDState *s = bs->opaque;
Error *local_err = NULL;
int ret;
bdrv_qed_close(bs);
bdrv_qed_init_state(bs);
qemu_co_mutex_lock(&s->table_lock);
ret = bdrv_qed_do_open(bs, NULL, bs->open_flags, &local_err);
qemu_co_mutex_unlock(&s->table_lock);
if (local_err) {
error_propagate_prepend(errp, local_err,
"Could not reopen qed layer: ");
return;
} else if (ret < 0) {
error_setg_errno(errp, -ret, "Could not reopen qed layer");
return;
}
}
static int bdrv_qed_co_check(BlockDriverState *bs, BdrvCheckResult *result,
BdrvCheckMode fix)
{
BDRVQEDState *s = bs->opaque;
int ret;
qemu_co_mutex_lock(&s->table_lock);
ret = qed_check(s, result, !!fix);
qemu_co_mutex_unlock(&s->table_lock);
return ret;
}
static QemuOptsList qed_create_opts = {
.name = "qed-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(qed_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size"
},
{
.name = BLOCK_OPT_BACKING_FILE,
.type = QEMU_OPT_STRING,
.help = "File name of a base image"
},
{
.name = BLOCK_OPT_BACKING_FMT,
.type = QEMU_OPT_STRING,
.help = "Image format of the base image"
},
{
.name = BLOCK_OPT_CLUSTER_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Cluster size (in bytes)",
.def_value_str = stringify(QED_DEFAULT_CLUSTER_SIZE)
},
{
.name = BLOCK_OPT_TABLE_SIZE,
.type = QEMU_OPT_SIZE,
.help = "L1/L2 table size (in clusters)"
},
{ /* end of list */ }
}
};
static BlockDriver bdrv_qed = {
.format_name = "qed",
.instance_size = sizeof(BDRVQEDState),
.create_opts = &qed_create_opts,
.supports_backing = true,
.bdrv_probe = bdrv_qed_probe,
.bdrv_open = bdrv_qed_open,
.bdrv_close = bdrv_qed_close,
.bdrv_reopen_prepare = bdrv_qed_reopen_prepare,
.bdrv_child_perm = bdrv_format_default_perms,
.bdrv_co_create = bdrv_qed_co_create,
.bdrv_co_create_opts = bdrv_qed_co_create_opts,
.bdrv_has_zero_init = bdrv_has_zero_init_1,
.bdrv_co_block_status = bdrv_qed_co_block_status,
.bdrv_co_readv = bdrv_qed_co_readv,
.bdrv_co_writev = bdrv_qed_co_writev,
.bdrv_co_pwrite_zeroes = bdrv_qed_co_pwrite_zeroes,
.bdrv_co_truncate = bdrv_qed_co_truncate,
.bdrv_getlength = bdrv_qed_getlength,
.bdrv_get_info = bdrv_qed_get_info,
.bdrv_refresh_limits = bdrv_qed_refresh_limits,
.bdrv_change_backing_file = bdrv_qed_change_backing_file,
.bdrv_co_invalidate_cache = bdrv_qed_co_invalidate_cache,
.bdrv_co_check = bdrv_qed_co_check,
.bdrv_detach_aio_context = bdrv_qed_detach_aio_context,
.bdrv_attach_aio_context = bdrv_qed_attach_aio_context,
.bdrv_co_drain_begin = bdrv_qed_co_drain_begin,
};
static void bdrv_qed_init(void)
{
bdrv_register(&bdrv_qed);
}
block_init(bdrv_qed_init);
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