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block/file-win32: add reopen handlers 

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>
Tested-by: Helge Konetzka <hk@zapateado.de>
Message-Id: <20210825173625.19415-1-viktor.prutyanov@phystech.edu>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
master
Viktor Prutyanov 2021-08-25 20:36:25 +03:00 committed by Hanna Reitz
parent 28031d5c74
commit ebd979c74e
1 changed files with 100 additions and 1 deletions
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101
block/file-win32.c
View File

@ -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 +638,97 @@ 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;
if (s->type != FTYPE_FILE) {
error_setg(errp, "Can only reopen files");
return -EINVAL;
}
rs = g_new0(BDRVRawReopenState, 1);
/*
* We do not support changing any options (only flags). By leaving
* all options in state->options, we tell the generic reopen code
* that we do not support changing any of them, so it will verify
* that their values did not change.
*/
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");
CloseHandle(rs->hfile);
goto fail;
}
}
state->opaque = rs;
return 0;
fail:
g_free(rs);
state->opaque = NULL;
return ret;
}
static void raw_reopen_commit(BDRVReopenState *state)
{
BDRVRawState *s = state->bs->opaque;
BDRVRawReopenState *rs = state->opaque;
assert(rs != NULL);
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 +754,10 @@ 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,