xemu-project/xemu
1
0
Fork 0
mirror of https://github.com/xemu-project/xemu.git synced 2024-12-13 23:08:57 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity
adcff99a6b
xemu/block/qed.c
Vladimir Sementsov-Ogievskiy f34b2bcf8c block: use int64_t instead of int in driver write_zeroes handlers 
We are generally moving to int64_t for both offset and bytes parameters
on all io paths.

Main motivation is realization of 64-bit write_zeroes operation for
fast zeroing large disk chunks, up to the whole disk.

We chose signed type, to be consistent with off_t (which is signed) and
with possibility for signed return type (where negative value means
error).

So, convert driver write_zeroes handlers bytes parameter to int64_t.

The only caller of all updated function is bdrv_co_do_pwrite_zeroes().

bdrv_co_do_pwrite_zeroes() itself is of course OK with widening of
callee parameter type. Also, bdrv_co_do_pwrite_zeroes()'s
max_write_zeroes is limited to INT_MAX. So, updated functions all are
safe, they will not get "bytes" larger than before.

Still, let's look through all updated functions, and add assertions to
the ones which are actually unprepared to values larger than INT_MAX.
For these drivers also set explicit max_pwrite_zeroes limit.

Let's go:

blkdebug: calculations can't overflow, thanks to
  bdrv_check_qiov_request() in generic layer. rule_check() and
  bdrv_co_pwrite_zeroes() both have 64bit argument.

blklogwrites: pass to blk_log_writes_co_log() with 64bit argument.

blkreplay, copy-on-read, filter-compress: pass to
  bdrv_co_pwrite_zeroes() which is OK

copy-before-write: Calls cbw_do_copy_before_write() and
  bdrv_co_pwrite_zeroes, both have 64bit argument.

file-posix: both handler calls raw_do_pwrite_zeroes, which is updated.
  In raw_do_pwrite_zeroes() calculations are OK due to
  bdrv_check_qiov_request(), bytes go to RawPosixAIOData::aio_nbytes
  which is uint64_t.
  Check also where that uint64_t gets handed:
  handle_aiocb_write_zeroes_block() passes a uint64_t[2] to
  ioctl(BLKZEROOUT), handle_aiocb_write_zeroes() calls do_fallocate()
  which takes off_t (and we compile to always have 64-bit off_t), as
  does handle_aiocb_write_zeroes_unmap. All look safe.

gluster: bytes go to GlusterAIOCB::size which is int64_t and to
  glfs_zerofill_async works with off_t.

iscsi: Aha, here we deal with iscsi_writesame16_task() that has
  uint32_t num_blocks argument and iscsi_writesame16_task() has
  uint16_t argument. Make comments, add assertions and clarify
  max_pwrite_zeroes calculation.
  iscsi_allocmap_() functions already has int64_t argument
  is_byte_request_lun_aligned is simple to update, do it.

mirror_top: pass to bdrv_mirror_top_do_write which has uint64_t
  argument

nbd: Aha, here we have protocol limitation, and NBDRequest::len is
  uint32_t. max_pwrite_zeroes is cleanly set to 32bit value, so we are
  OK for now.

nvme: Again, protocol limitation. And no inherent limit for
  write-zeroes at all. But from code that calculates cdw12 it's obvious
  that we do have limit and alignment. Let's clarify it. Also,
  obviously the code is not prepared to handle bytes=0. Let's handle
  this case too.
  trace events already 64bit

preallocate: pass to handle_write() and bdrv_co_pwrite_zeroes(), both
  64bit.

rbd: pass to qemu_rbd_start_co() which is 64bit.

qcow2: offset + bytes and alignment still works good (thanks to
  bdrv_check_qiov_request()), so tail calculation is OK
  qcow2_subcluster_zeroize() has 64bit argument, should be OK
  trace events updated

qed: qed_co_request wants int nb_sectors. Also in code we have size_t
  used for request length which may be 32bit. So, let's just keep
  INT_MAX as a limit (aligning it down to pwrite_zeroes_alignment) and
  don't care.

raw-format: Is OK. raw_adjust_offset and bdrv_co_pwrite_zeroes are both
  64bit.

throttle: Both throttle_group_co_io_limits_intercept() and
  bdrv_co_pwrite_zeroes() are 64bit.

vmdk: pass to vmdk_pwritev which is 64bit

quorum: pass to quorum_co_pwritev() which is 64bit

Hooray!

At this point all block drivers are prepared to support 64bit
write-zero requests, or have explicitly set max_pwrite_zeroes.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210903102807.27127-8-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: use <= rather than < in assertions relying on max_pwrite_zeroes]
Signed-off-by: Eric Blake <eblake@redhat.com>
2021-09-29 13:46:32 -05:00

1657 lines
48 KiB
C
Raw Blame History

/*
* 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/main-loop.h"
#include "qemu/module.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;
int ret;
assert(s->allocating_acb || s->allocating_write_reqs_plugged);
buf = qemu_blockalign(s->bs, len);
ret = bdrv_co_pread(s->bs->file, 0, len, buf, 0);
if (ret < 0) {
goto out;
}
/* Update header */
qed_header_cpu_to_le(&s->header, (QEDHeader *) buf);
ret = bdrv_co_pwrite(s->bs->file, 0, len, buf, 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) {
error_setg(errp, "Failed to read QED header");
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)) {
error_setg(errp, "QED cluster size is invalid");
return -EINVAL;
}
/* Round down file size to the last cluster */
file_size = bdrv_getlength(bs->file->bs);
if (file_size < 0) {
error_setg(errp, "Failed to get file length");
return file_size;
}
s->file_size = qed_start_of_cluster(s, file_size);
if (!qed_is_table_size_valid(s->header.table_size)) {
error_setg(errp, "QED table size is invalid");
return -EINVAL;
}
if (!qed_is_image_size_valid(s->header.image_size,
s->header.cluster_size,
s->header.table_size)) {
error_setg(errp, "QED image size is invalid");
return -EINVAL;
}
if (!qed_check_table_offset(s, s->header.l1_table_offset)) {
error_setg(errp, "QED table offset is invalid");
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) {
error_setg(errp, "QED header size is too large");
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) {
error_setg(errp, "QED backing filename offset is invalid");
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) {
error_setg(errp, "Failed to read backing filename");
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) {
error_setg(errp, "Failed to update header");
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) {
error_setg(errp, "Failed to read L1 table");
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) {
error_setg(errp, "Image corrupted");
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_of_bds,
BDRV_CHILD_IMAGE, 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;
bs->bl.max_pwrite_zeroes = QEMU_ALIGN_DOWN(INT_MAX, 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_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL,
errp);
if (!blk) {
ret = -EPERM;
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;
/*
* The QED format associates file length with allocation status,
* so a new file (which is empty) must have a length of 0.
*/
ret = blk_truncate(blk, 0, true, PREALLOC_MODE_OFF, 0, 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(BlockDriver *drv,
const char *filename,
QemuOpts *opts,
Error **errp)
{
BlockdevCreateOptions *create_options = NULL;
QDict *qdict;
Visitor *v;
BlockDriverState *bs = 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, errp);
if (ret < 0) {
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, errp);
visit_free(v);
if (!create_options) {
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
*
* 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)
{
if (s->bs->backing) {
BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO);
return bdrv_co_preadv(s->bs->backing, pos, qiov->size, qiov, 0);
}
qemu_iovec_memset(qiov, 0, 0, qiov->size);
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;
int ret;
/* Skip copy entirely if there is no work to do */
if (len == 0) {
return 0;
}
qemu_iovec_init_buf(&qiov, qemu_blockalign(s->bs, len), len);
ret = qed_read_backing_file(s, pos, &qiov);
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(qemu_iovec_buf(&qiov));
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);
} 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);
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,
int64_t bytes,
BdrvRequestFlags flags)
{
BDRVQEDState *s = bs->opaque;
/*
* Zero writes start without an I/O buffer. If a buffer becomes necessary
* then it will be allocated during request processing.
*/
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, bytes);
/*
* QED is not prepared for 63bit write-zero requests, so rely on
* max_pwrite_zeroes.
*/
assert(bytes <= INT_MAX);
/* Fall back if the request is not aligned */
if (qed_offset_into_cluster(s, offset) ||
qed_offset_into_cluster(s, bytes)) {
return -ENOTSUP;
}
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,
bool exact,
PreallocMode prealloc,
BdrvRequestFlags flags,
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;
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;
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, errp);
qemu_co_mutex_unlock(&s->table_lock);
if (ret < 0) {
error_prepend(errp, "Could not reopen qed layer: ");
}
}
static int coroutine_fn 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,
.is_format = true,
.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_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);
Reference in New Issue View Git Blame Copy Permalink