| Message ID | 20210824234817.13343-1-viktor.prutyanov@phystech.edu (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v4] block/file-win32: add reopen handlers | expand |
On 25.08.21 01:48, 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> > Tested-by: Helge Konetzka <hk@zapateado.de> > --- > v2: > - fix indentation in raw_reopen_prepare > - free rs if raw_reopen_prepare fails > v3: > - restore suggested-by field missed in v2 > v4: > - add file type check > - add comment about options > - replace rs check with assert in raw_reopen_commit > > block/file-win32.c | 100 ++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 99 insertions(+), 1 deletion(-) > > diff --git a/block/file-win32.c b/block/file-win32.c > index 2642088bd6..8320495f2b 100644 > --- a/block/file-win32.c > +++ b/block/file-win32.c [...] > @@ -634,6 +638,96 @@ 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"); > + goto fail; I believe if we fail here, we’ve already opened rs->hfile, so we must close it or we’d leak it. (Sorry I missed this in my v3 review :/) Hanna > + } > + } > + > + state->opaque = rs; > + > + return 0; > + > +fail: > + g_free(rs); > + state->opaque = NULL; > + > + return ret; > +}
diff --git a/block/file-win32.c b/block/file-win32.c index 2642088bd6..8320495f2b 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 +638,96 @@ 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"); + 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 +753,10 @@ 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,