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22.04.2019, 13:50, "Yury Kotov" <yury-ko...@yandex-team.ru>:
> Currently, there is no information about error if outgoing migration was
> failed
> because of file channel errors.
> Example (QMP session):
> -> { "execute": "migrate", "arguments": { "uri": "exec:head -c 1" }}
> <- { "return": {} }
> ...
> -> { "execute": "query-migrate" }
> <- { "return": { "status": "failed" }} // There is not error's description
>
> And even in the QEMU's output there is nothing.
>
> This patch
> 1) Adds errp for the most of QEMUFileOps
> 2) Adds qemu_file_get_error_obj/qemu_file_set_error_obj
> 3) And finally using of qemu_file_get_error_obj in migration.c
>
> And now, the status for the mentioned fail will be:
> -> { "execute": "query-migrate" }
> <- { "return": { "status": "failed",
> "error-desc": "Unable to write to command: Broken pipe" }}
>
> Signed-off-by: Yury Kotov <yury-ko...@yandex-team.ru>
> ---
> migration/migration.c | 10 ++++--
> migration/qemu-file-channel.c | 30 +++++++++--------
> migration/qemu-file.c | 63 ++++++++++++++++++++++++++++-------
> migration/qemu-file.h | 15 ++++++---
> migration/savevm.c | 6 ++--
> 5 files changed, 88 insertions(+), 36 deletions(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 609e0df5d0..7bcdc4613b 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -2949,6 +2949,7 @@ static MigThrError
> migration_detect_error(MigrationState *s)
> {
> int ret;
> int state = s->state;
> + Error *local_error = NULL;
>
> if (state == MIGRATION_STATUS_CANCELLING ||
> state == MIGRATION_STATUS_CANCELLED) {
> @@ -2957,13 +2958,18 @@ static MigThrError
> migration_detect_error(MigrationState *s)
> }
>
> /* Try to detect any file errors */
> - ret = qemu_file_get_error(s->to_dst_file);
> -
> + ret = qemu_file_get_error_obj(s->to_dst_file, &local_error);
> if (!ret) {
> /* Everything is fine */
> + assert(!local_error);
> return MIG_THR_ERR_NONE;
> }
>
> + if (local_error) {
> + migrate_set_error(s, local_error);
> + error_free(local_error);
> + }
> +
> if (state == MIGRATION_STATUS_POSTCOPY_ACTIVE && ret == -EIO) {
> /*
> * For postcopy, we allow the network to be down for a
> diff --git a/migration/qemu-file-channel.c b/migration/qemu-file-channel.c
> index 8e639eb496..c382ea2d78 100644
> --- a/migration/qemu-file-channel.c
> +++ b/migration/qemu-file-channel.c
> @@ -33,7 +33,8 @@
> static ssize_t channel_writev_buffer(void *opaque,
> struct iovec *iov,
> int iovcnt,
> - int64_t pos)
> + int64_t pos,
> + Error **errp)
> {
> QIOChannel *ioc = QIO_CHANNEL(opaque);
> ssize_t done = 0;
> @@ -47,7 +48,7 @@ static ssize_t channel_writev_buffer(void *opaque,
>
> while (nlocal_iov > 0) {
> ssize_t len;
> - len = qio_channel_writev(ioc, local_iov, nlocal_iov, NULL);
> + len = qio_channel_writev(ioc, local_iov, nlocal_iov, errp);
> if (len == QIO_CHANNEL_ERR_BLOCK) {
> if (qemu_in_coroutine()) {
> qio_channel_yield(ioc, G_IO_OUT);
> @@ -57,7 +58,6 @@ static ssize_t channel_writev_buffer(void *opaque,
> continue;
> }
> if (len < 0) {
> - /* XXX handle Error objects */
> done = -EIO;
> goto cleanup;
> }
> @@ -75,13 +75,14 @@ static ssize_t channel_writev_buffer(void *opaque,
> static ssize_t channel_get_buffer(void *opaque,
> uint8_t *buf,
> int64_t pos,
> - size_t size)
> + size_t size,
> + Error **errp)
> {
> QIOChannel *ioc = QIO_CHANNEL(opaque);
> ssize_t ret;
>
> do {
> - ret = qio_channel_read(ioc, (char *)buf, size, NULL);
> + ret = qio_channel_read(ioc, (char *)buf, size, errp);
> if (ret < 0) {
> if (ret == QIO_CHANNEL_ERR_BLOCK) {
> if (qemu_in_coroutine()) {
> @@ -90,7 +91,6 @@ static ssize_t channel_get_buffer(void *opaque,
> qio_channel_wait(ioc, G_IO_IN);
> }
> } else {
> - /* XXX handle Error * object */
> return -EIO;
> }
> }
> @@ -100,18 +100,20 @@ static ssize_t channel_get_buffer(void *opaque,
> }
>
> -static int channel_close(void *opaque)
> +static int channel_close(void *opaque, Error **errp)
> {
> + int ret;
> QIOChannel *ioc = QIO_CHANNEL(opaque);
> - qio_channel_close(ioc, NULL);
> + ret = qio_channel_close(ioc, errp);
> object_unref(OBJECT(ioc));
> - return 0;
> + return ret;
> }
>
> static int channel_shutdown(void *opaque,
> bool rd,
> - bool wr)
> + bool wr,
> + Error **errp)
> {
> QIOChannel *ioc = QIO_CHANNEL(opaque);
>
> @@ -125,8 +127,7 @@ static int channel_shutdown(void *opaque,
> } else {
> mode = QIO_CHANNEL_SHUTDOWN_WRITE;
> }
> - if (qio_channel_shutdown(ioc, mode, NULL) < 0) {
> - /* XXX handler Error * object */
> + if (qio_channel_shutdown(ioc, mode, errp) < 0) {
> return -EIO;
> }
> }
> @@ -135,11 +136,12 @@ static int channel_shutdown(void *opaque,
>
> static int channel_set_blocking(void *opaque,
> - bool enabled)
> + bool enabled,
> + Error **errp)
> {
> QIOChannel *ioc = QIO_CHANNEL(opaque);
>
> - if (qio_channel_set_blocking(ioc, enabled, NULL) < 0) {
> + if (qio_channel_set_blocking(ioc, enabled, errp) < 0) {
> return -1;
> }
> return 0;
> diff --git a/migration/qemu-file.c b/migration/qemu-file.c
> index 977b9ae07c..c52160e08b 100644
> --- a/migration/qemu-file.c
> +++ b/migration/qemu-file.c
> @@ -29,6 +29,7 @@
> #include "migration.h"
> #include "qemu-file.h"
> #include "trace.h"
> +#include "qapi/error.h"
>
> #define IO_BUF_SIZE 32768
> #define MAX_IOV_SIZE MIN(IOV_MAX, 64)
> @@ -52,6 +53,7 @@ struct QEMUFile {
> unsigned int iovcnt;
>
> int last_error;
> + Error *last_error_obj;
> };
>
> /*
> @@ -63,7 +65,7 @@ int qemu_file_shutdown(QEMUFile *f)
> if (!f->ops->shut_down) {
> return -ENOSYS;
> }
> - return f->ops->shut_down(f->opaque, true, true);
> + return f->ops->shut_down(f->opaque, true, true, NULL);
> }
>
> /*
> @@ -108,24 +110,55 @@ void qemu_file_set_hooks(QEMUFile *f, const
> QEMUFileHooks *hooks)
> }
>
> /*
> - * Get last error for stream f
> + * Get last error for stream f with optional Error*
> *
> * Return negative error value if there has been an error on previous
> * operations, return 0 if no error happened.
> + * Optional, it returns Error* in errp, but it may be NULL even if return
> value
> + * is not 0.
> *
> */
> -int qemu_file_get_error(QEMUFile *f)
> +int qemu_file_get_error_obj(QEMUFile *f, Error **errp)
> {
> + if (errp) {
> + *errp = f->last_error_obj ? error_copy(f->last_error_obj) : NULL;
> + }
> return f->last_error;
> }
>
> -void qemu_file_set_error(QEMUFile *f, int ret)
> +/*
> + * Set the last error for stream f with optional Error*
> + */
> +void qemu_file_set_error_obj(QEMUFile *f, int ret, Error *err)
> {
> - if (f->last_error == 0) {
> + if (f->last_error == 0 && ret) {
> f->last_error = ret;
> + error_propagate(&f->last_error_obj, err);
> + } else if (err) {
> + error_report_err(err);
> }
> }
>
> +/*
> + * Get last error for stream f
> + *
> + * Return negative error value if there has been an error on previous
> + * operations, return 0 if no error happened.
> + *
> + */
> +int qemu_file_get_error(QEMUFile *f)
> +{
> + return qemu_file_get_error_obj(f, NULL);
> +}
> +
> +/*
> + * Set the last error for stream f
> + */
> +void qemu_file_set_error(QEMUFile *f, int ret)
> +{
> + qemu_file_set_error_obj(f, ret, NULL);
> +}
> +
> bool qemu_file_is_writable(QEMUFile *f)
> {
> return f->ops->writev_buffer;
> @@ -177,6 +210,7 @@ void qemu_fflush(QEMUFile *f)
> {
> ssize_t ret = 0;
> ssize_t expect = 0;
> + Error *local_error = NULL;
>
> if (!qemu_file_is_writable(f)) {
> return;
> @@ -184,7 +218,8 @@ void qemu_fflush(QEMUFile *f)
>
> if (f->iovcnt > 0) {
> expect = iov_size(f->iov, f->iovcnt);
> - ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt, f->pos);
> + ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt, f->pos,
> + &local_error);
>
> qemu_iovec_release_ram(f);
> }
> @@ -196,7 +231,7 @@ void qemu_fflush(QEMUFile *f)
> * data set we requested, so sanity check that.
> */
> if (ret != expect) {
> - qemu_file_set_error(f, ret < 0 ? ret : -EIO);
> + qemu_file_set_error_obj(f, ret < 0 ? ret : -EIO, local_error);
> }
> f->buf_index = 0;
> f->iovcnt = 0;
> @@ -284,6 +319,7 @@ static ssize_t qemu_fill_buffer(QEMUFile *f)
> {
> int len;
> int pending;
> + Error *local_error = NULL;
>
> assert(!qemu_file_is_writable(f));
>
> @@ -295,14 +331,16 @@ static ssize_t qemu_fill_buffer(QEMUFile *f)
> f->buf_size = pending;
>
> len = f->ops->get_buffer(f->opaque, f->buf + pending, f->pos,
> - IO_BUF_SIZE - pending);
> + IO_BUF_SIZE - pending, &local_error);
> if (len > 0) {
> f->buf_size += len;
> f->pos += len;
> } else if (len == 0) {
> - qemu_file_set_error(f, -EIO);
> + qemu_file_set_error_obj(f, -EIO, local_error);
> } else if (len != -EAGAIN) {
> - qemu_file_set_error(f, len);
> + qemu_file_set_error_obj(f, len, local_error);
> + } else {
> + error_free(local_error);
> }
>
> return len;
> @@ -328,7 +366,7 @@ int qemu_fclose(QEMUFile *f)
> ret = qemu_file_get_error(f);
>
> if (f->ops->close) {
> - int ret2 = f->ops->close(f->opaque);
> + int ret2 = f->ops->close(f->opaque, NULL);
> if (ret >= 0) {
> ret = ret2;
> }
> @@ -339,6 +377,7 @@ int qemu_fclose(QEMUFile *f)
> if (f->last_error) {
> ret = f->last_error;
> }
> + error_free(f->last_error_obj);
> g_free(f);
> trace_qemu_file_fclose();
> return ret;
> @@ -784,6 +823,6 @@ void qemu_put_counted_string(QEMUFile *f, const char *str)
> void qemu_file_set_blocking(QEMUFile *f, bool block)
> {
> if (f->ops->set_blocking) {
> - f->ops->set_blocking(f->opaque, block);
> + f->ops->set_blocking(f->opaque, block, NULL);
> }
> }
> diff --git a/migration/qemu-file.h b/migration/qemu-file.h
> index 13baf896bd..eb886db65f 100644
> --- a/migration/qemu-file.h
> +++ b/migration/qemu-file.h
> @@ -32,7 +32,8 @@
> * bytes actually read should be returned.
> */
> typedef ssize_t (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf,
> - int64_t pos, size_t size);
> + int64_t pos, size_t size,
> + Error **errp);
>
> /* Close a file
> *
> @@ -41,7 +42,7 @@ typedef ssize_t (QEMUFileGetBufferFunc)(void *opaque,
> uint8_t *buf,
> * The meaning of return value on success depends on the specific back-end
> being
> * used.
> */
> -typedef int (QEMUFileCloseFunc)(void *opaque);
> +typedef int (QEMUFileCloseFunc)(void *opaque, Error **errp);
>
> /* Called to return the OS file descriptor associated to the QEMUFile.
> */
> @@ -49,14 +50,15 @@ typedef int (QEMUFileGetFD)(void *opaque);
>
> /* Called to change the blocking mode of the file
> */
> -typedef int (QEMUFileSetBlocking)(void *opaque, bool enabled);
> +typedef int (QEMUFileSetBlocking)(void *opaque, bool enabled, Error **errp);
>
> /*
> * This function writes an iovec to file. The handler must write all
> * of the data or return a negative errno value.
> */
> typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
> - int iovcnt, int64_t pos);
> + int iovcnt, int64_t pos,
> + Error **errp);
>
> /*
> * This function provides hooks around different
> @@ -97,7 +99,8 @@ typedef QEMUFile *(QEMURetPathFunc)(void *opaque);
> * Existing blocking reads/writes must be woken
> * Returns 0 on success, -err on error
> */
> -typedef int (QEMUFileShutdownFunc)(void *opaque, bool rd, bool wr);
> +typedef int (QEMUFileShutdownFunc)(void *opaque, bool rd, bool wr,
> + Error **errp);
>
> typedef struct QEMUFileOps {
> QEMUFileGetBufferFunc *get_buffer;
> @@ -149,6 +152,8 @@ void qemu_update_position(QEMUFile *f, size_t size);
> void qemu_file_reset_rate_limit(QEMUFile *f);
> void qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate);
> int64_t qemu_file_get_rate_limit(QEMUFile *f);
> +int qemu_file_get_error_obj(QEMUFile *f, Error **errp);
> +void qemu_file_set_error_obj(QEMUFile *f, int ret, Error *err);
> void qemu_file_set_error(QEMUFile *f, int ret);
> int qemu_file_shutdown(QEMUFile *f);
> QEMUFile *qemu_file_get_return_path(QEMUFile *f);
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 34bcad3807..a619af744d 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -124,7 +124,7 @@ static struct mig_cmd_args {
> /* savevm/loadvm support */
>
> static ssize_t block_writev_buffer(void *opaque, struct iovec *iov, int
> iovcnt,
> - int64_t pos)
> + int64_t pos, Error **errp)
> {
> int ret;
> QEMUIOVector qiov;
> @@ -139,12 +139,12 @@ static ssize_t block_writev_buffer(void *opaque, struct
> iovec *iov, int iovcnt,
> }
>
> static ssize_t block_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
> - size_t size)
> + size_t size, Error **errp)
> {
> return bdrv_load_vmstate(opaque, buf, pos, size);
> }
>
> -static int bdrv_fclose(void *opaque)
> +static int bdrv_fclose(void *opaque, Error **errp)
> {
> return bdrv_flush(opaque);
> }
> --
> 2.21.0
