* [PATCH] block/file-win32: add reopen handlers
@ 2021-08-17 10:12 Viktor Prutyanov
2021-08-17 10:23 ` Philippe Mathieu-Daudé
0 siblings, 1 reply; 2+ messages in thread
From: Viktor Prutyanov @ 2021-08-17 10:12 UTC (permalink / raw)
To: kwolf, hreitz, sw, qemu-block, qemu-devel; +Cc: Viktor Prutyanov
Make 'qemu-img commit' work on Windows.
Command 'commit' requires reopening backing file in RW mode. So,
add reopen prepare/commit/abort handlers and change dwShareMode
for CreateFile call in order to allow further read/write reopening.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/418
Suggested-by: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Viktor Prutyanov <viktor.prutyanov@phystech.edu>
---
block/file-win32.c | 85 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 84 insertions(+), 1 deletion(-)
diff --git a/block/file-win32.c b/block/file-win32.c
index 2642088bd6..e44878e6be 100644
--- a/block/file-win32.c
+++ b/block/file-win32.c
@@ -58,6 +58,10 @@ typedef struct BDRVRawState {
QEMUWin32AIOState *aio;
} BDRVRawState;
+typedef struct BDRVRawReopenState {
+ HANDLE hfile;
+} BDRVRawReopenState;
+
/*
* Read/writes the data to/from a given linear buffer.
*
@@ -392,7 +396,7 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
}
s->hfile = CreateFile(filename, access_flags,
- FILE_SHARE_READ, NULL,
+ FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
OPEN_EXISTING, overlapped, NULL);
if (s->hfile == INVALID_HANDLE_VALUE) {
int err = GetLastError();
@@ -634,6 +638,81 @@ static int coroutine_fn raw_co_create_opts(BlockDriver *drv,
return raw_co_create(&options, errp);
}
+static int raw_reopen_prepare(BDRVReopenState *state,
+ BlockReopenQueue *queue, Error **errp)
+{
+ BDRVRawState *s = state->bs->opaque;
+ BDRVRawReopenState *rs;
+ int access_flags;
+ DWORD overlapped;
+ int ret = 0;
+
+ rs = state->opaque = g_new0(BDRVRawReopenState, 1);
+
+ raw_parse_flags(state->flags, s->aio != NULL, &access_flags, &overlapped);
+ rs->hfile = CreateFile(state->bs->filename, access_flags,
+ FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
+ OPEN_EXISTING, overlapped, NULL);
+
+ if (rs->hfile == INVALID_HANDLE_VALUE) {
+ int err = GetLastError();
+
+ error_setg_win32(errp, err, "Could not reopen '%s'",
+ state->bs->filename);
+ if (err == ERROR_ACCESS_DENIED) {
+ ret = -EACCES;
+ } else {
+ ret = -EINVAL;
+ }
+ goto fail;
+ }
+
+ if (s->aio) {
+ ret = win32_aio_attach(s->aio, rs->hfile);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not enable AIO");
+ goto fail;
+ }
+ }
+
+ return 0;
+
+fail:
+ return ret;
+}
+
+static void raw_reopen_commit(BDRVReopenState *state)
+{
+ BDRVRawState *s = state->bs->opaque;
+ BDRVRawReopenState *rs = state->opaque;
+
+ if (!rs) {
+ return;
+ }
+
+ CloseHandle(s->hfile);
+ s->hfile = rs->hfile;
+
+ g_free(rs);
+ state->opaque = NULL;
+}
+
+static void raw_reopen_abort(BDRVReopenState *state)
+{
+ BDRVRawReopenState *rs = state->opaque;
+
+ if (!rs) {
+ return;
+ }
+
+ if (rs->hfile != INVALID_HANDLE_VALUE) {
+ CloseHandle(rs->hfile);
+ }
+
+ g_free(rs);
+ state->opaque = NULL;
+}
+
static QemuOptsList raw_create_opts = {
.name = "raw-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
@@ -659,6 +738,10 @@ BlockDriver bdrv_file = {
.bdrv_co_create_opts = raw_co_create_opts,
.bdrv_has_zero_init = bdrv_has_zero_init_1,
+ .bdrv_reopen_prepare = raw_reopen_prepare,
+ .bdrv_reopen_commit = raw_reopen_commit,
+ .bdrv_reopen_abort = raw_reopen_abort,
+
.bdrv_aio_preadv = raw_aio_preadv,
.bdrv_aio_pwritev = raw_aio_pwritev,
.bdrv_aio_flush = raw_aio_flush,
--
2.21.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] block/file-win32: add reopen handlers
2021-08-17 10:12 [PATCH] block/file-win32: add reopen handlers Viktor Prutyanov
@ 2021-08-17 10:23 ` Philippe Mathieu-Daudé
0 siblings, 0 replies; 2+ messages in thread
From: Philippe Mathieu-Daudé @ 2021-08-17 10:23 UTC (permalink / raw)
To: Viktor Prutyanov, kwolf, hreitz, sw, qemu-block, qemu-devel
Hi Viktor,
Thanks for the patch :)
On 8/17/21 12:12 PM, Viktor Prutyanov wrote:
> Make 'qemu-img commit' work on Windows.
>
> Command 'commit' requires reopening backing file in RW mode. So,
> add reopen prepare/commit/abort handlers and change dwShareMode
> for CreateFile call in order to allow further read/write reopening.
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/418
> Suggested-by: Hanna Reitz <hreitz@redhat.com>
> Signed-off-by: Viktor Prutyanov <viktor.prutyanov@phystech.edu>
> ---
> block/file-win32.c | 85 +++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 84 insertions(+), 1 deletion(-)
>
> diff --git a/block/file-win32.c b/block/file-win32.c
> index 2642088bd6..e44878e6be 100644
> --- a/block/file-win32.c
> +++ b/block/file-win32.c
> @@ -58,6 +58,10 @@ typedef struct BDRVRawState {
> QEMUWin32AIOState *aio;
> } BDRVRawState;
>
> +typedef struct BDRVRawReopenState {
> + HANDLE hfile;
> +} BDRVRawReopenState;
> +
> /*
> * Read/writes the data to/from a given linear buffer.
> *
> @@ -392,7 +396,7 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
> }
>
> s->hfile = CreateFile(filename, access_flags,
> - FILE_SHARE_READ, NULL,
> + FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
> OPEN_EXISTING, overlapped, NULL);
> if (s->hfile == INVALID_HANDLE_VALUE) {
> int err = GetLastError();
> @@ -634,6 +638,81 @@ static int coroutine_fn raw_co_create_opts(BlockDriver *drv,
> return raw_co_create(&options, errp);
> }
>
> +static int raw_reopen_prepare(BDRVReopenState *state,
> + BlockReopenQueue *queue, Error **errp)
Invalid style alignment.
> +{
> + BDRVRawState *s = state->bs->opaque;
> + BDRVRawReopenState *rs;
> + int access_flags;
> + DWORD overlapped;
> + int ret = 0;
> +
> + rs = state->opaque = g_new0(BDRVRawReopenState, 1);
> +
> + raw_parse_flags(state->flags, s->aio != NULL, &access_flags, &overlapped);
> + rs->hfile = CreateFile(state->bs->filename, access_flags,
> + FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
> + OPEN_EXISTING, overlapped, NULL);
> +
> + if (rs->hfile == INVALID_HANDLE_VALUE) {
> + int err = GetLastError();
> +
> + error_setg_win32(errp, err, "Could not reopen '%s'",
> + state->bs->filename);
> + if (err == ERROR_ACCESS_DENIED) {
> + ret = -EACCES;
> + } else {
> + ret = -EINVAL;
> + }
> + goto fail;
> + }
> +
> + if (s->aio) {
> + ret = win32_aio_attach(s->aio, rs->hfile);
> + if (ret < 0) {
> + error_setg_errno(errp, -ret, "Could not enable AIO");
> + goto fail;
> + }
> + }
To avoid non-NULL value in state->opaque on failure,
I'd use in prologue:
rs = g_new0(BDRVRawReopenState, 1);
and here:
state->opaque = rs;
> + return 0;
> +
> +fail:
Shouldn't we free state->opaque on failure? (I'm not sure because
I don't know well the bdrv_reopen_prepare handler).
> + return ret;
> +}
> +
> +static void raw_reopen_commit(BDRVReopenState *state)
> +{
> + BDRVRawState *s = state->bs->opaque;
> + BDRVRawReopenState *rs = state->opaque;
> +
> + if (!rs) {
Indeed, raw_reopen_prepare() could let state->opaque non-NULL.
> + return;
> + }
> +
> + CloseHandle(s->hfile);
> + s->hfile = rs->hfile;
> +
> + g_free(rs);
> + state->opaque = NULL;
> +}
> +
> +static void raw_reopen_abort(BDRVReopenState *state)
> +{
> + BDRVRawReopenState *rs = state->opaque;
> +
> + if (!rs) {
> + return;
> + }
> +
> + if (rs->hfile != INVALID_HANDLE_VALUE) {
> + CloseHandle(rs->hfile);
> + }
> +
> + g_free(rs);
> + state->opaque = NULL;
> +}
> +
> static QemuOptsList raw_create_opts = {
> .name = "raw-create-opts",
> .head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
> @@ -659,6 +738,10 @@ BlockDriver bdrv_file = {
> .bdrv_co_create_opts = raw_co_create_opts,
> .bdrv_has_zero_init = bdrv_has_zero_init_1,
>
> + .bdrv_reopen_prepare = raw_reopen_prepare,
> + .bdrv_reopen_commit = raw_reopen_commit,
> + .bdrv_reopen_abort = raw_reopen_abort,
> +
> .bdrv_aio_preadv = raw_aio_preadv,
> .bdrv_aio_pwritev = raw_aio_pwritev,
> .bdrv_aio_flush = raw_aio_flush,
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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