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[Qemu-devel] [PATCH v2 14/16] block: raw-win32 driver reopen support
From: |
Jeff Cody |
Subject: |
[Qemu-devel] [PATCH v2 14/16] block: raw-win32 driver reopen support |
Date: |
Thu, 13 Sep 2012 11:49:52 -0400 |
This is the support for reopen, for win32. Note that there is a key
difference in the win32 reopen, namely that it is not guaranteed safe
like all the other drivers. Attempts are made to reopen the file, or
open the file in a new handle prior to closing the old handle. However,
this is not always feasible, and there are times when we must close the
existing file and then open the new file, breaking the transactional nature
of the reopen.
Signed-off-by: Jeff Cody <address@hidden>
---
block/raw-posix.c | 1 -
block/raw-win32.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 104 insertions(+), 1 deletion(-)
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 2407eeb..d0a931a 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -141,7 +141,6 @@ typedef struct BDRVRawState {
} BDRVRawState;
typedef struct BDRVRawReopenState {
- BDRVReopenState reopen_state;
int fd;
int open_flags;
#ifdef CONFIG_LINUX_AIO
diff --git a/block/raw-win32.c b/block/raw-win32.c
index 78c8306..cfa5def 100644
--- a/block/raw-win32.c
+++ b/block/raw-win32.c
@@ -31,6 +31,7 @@
#define FTYPE_FILE 0
#define FTYPE_CD 1
#define FTYPE_HARDDISK 2
+#define WINDOWS_VISTA 6
typedef struct BDRVRawState {
HANDLE hfile;
@@ -38,6 +39,10 @@ typedef struct BDRVRawState {
char drive_path[16]; /* format: "d:\" */
} BDRVRawState;
+typedef struct BDRVRawReopenState {
+ HANDLE hfile;
+} BDRVRawReopenState;
+
int qemu_ftruncate64(int fd, int64_t length)
{
LARGE_INTEGER li;
@@ -117,6 +122,102 @@ static int raw_open(BlockDriverState *bs, const char
*filename, int flags)
return 0;
}
+static int raw_reopen_prepare(BDRVReopenState *state, Error **errp)
+{
+ BDRVRawState *s;
+ BDRVRawReopenState *raw_s;
+ int ret = 0;
+ int access_flags;
+ DWORD overlapped;
+ OSVERSIONINFO osvi;
+
+ assert(state != NULL);
+ assert(state->bs != NULL);
+
+ s = state->bs->opaque;
+
+ state->opaque = g_malloc0(sizeof(BDRVRawReopenState));
+ raw_s = state->opaque;
+
+ raw_parse_flags(state->flags, &access_flags, &overlapped);
+
+ ZeroMemory(&osvi, sizeof(OSVERSIONINFO));
+ osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
+
+ GetVersionEx(&osvi);
+ raw_s->hfile = INVALID_HANDLE_VALUE;
+
+ if (osvi.dwMajorVersion >= WINDOWS_VISTA) {
+ raw_s->hfile = ReOpenFile(s->hfile, access_flags, FILE_SHARE_READ,
+ overlapped);
+ }
+
+ /* could not reopen the file handle, so fall back to opening
+ * new file (CreateFile) */
+ if (raw_s->hfile == INVALID_HANDLE_VALUE) {
+ raw_s->hfile = CreateFile(state->bs->filename, access_flags,
+ FILE_SHARE_READ, NULL, OPEN_EXISTING,
+ overlapped, NULL);
+ if (raw_s->hfile == INVALID_HANDLE_VALUE) {
+ /* this could happen because the access_flags requested are
+ * incompatible with the existing share mode of s->hfile,
+ * so our only option now is to close s->hfile, and try again.
+ * This could end badly */
+ CloseHandle(s->hfile);
+ s->hfile = INVALID_HANDLE_VALUE;
+ raw_s->hfile = CreateFile(state->bs->filename, access_flags,
+ FILE_SHARE_READ, NULL, OPEN_EXISTING,
+ overlapped, NULL);
+ if (raw_s->hfile == INVALID_HANDLE_VALUE) {
+ /* Unrecoverable error */
+ error_set(errp, ERROR_CLASS_GENERIC_ERROR,
+ "Fatal error reopening %s file; file closed and
cannot be opened\n",
+ state->bs->filename);
+ ret = -1;
+ } else{
+ /* since we had to close the original, go ahead and
+ * re-assign here */
+ s->hfile = raw_s->hfile;
+ raw_s->hfile = INVALID_HANDLE_VALUE;
+ }
+ }
+ }
+
+ return ret;
+}
+
+
+static void raw_reopen_commit(BDRVReopenState *state)
+{
+ BDRVRawReopenState *raw_s = state->opaque;
+ BDRVRawState *s = state->bs->opaque;
+
+ if (raw_s->hfile != INVALID_HANDLE_VALUE) {
+ CloseHandle(s->hfile);
+ s->hfile = raw_s->hfile;
+ }
+
+ g_free(state->opaque);
+ state->opaque = NULL;
+}
+
+
+static void raw_reopen_abort(BDRVReopenState *state)
+{
+ BDRVRawReopenState *raw_s = state->opaque;
+
+ /* nothing to do if NULL, we didn't get far enough */
+ if (raw_s == NULL) {
+ return;
+ }
+
+ if (raw_s->hfile != INVALID_HANDLE_VALUE) {
+ CloseHandle(raw_s->hfile);
+ }
+ g_free(state->opaque);
+ state->opaque = NULL;
+}
+
static int raw_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
@@ -287,6 +388,9 @@ static BlockDriver bdrv_file = {
.protocol_name = "file",
.instance_size = sizeof(BDRVRawState),
.bdrv_file_open = raw_open,
+ .bdrv_reopen_prepare = raw_reopen_prepare,
+ .bdrv_reopen_commit = raw_reopen_commit,
+ .bdrv_reopen_abort = raw_reopen_abort,
.bdrv_close = raw_close,
.bdrv_create = raw_create,
--
1.7.11.4
- Re: [Qemu-devel] [PATCH v2 09/16] block: raw image file reopen, (continued)
- [Qemu-devel] [PATCH v2 08/16] block: raw-posix image file reopen, Jeff Cody, 2012/09/13
- [Qemu-devel] [PATCH v2 07/16] block: move allocating aligned_buf into a helper function in raw_posix.c, Jeff Cody, 2012/09/13
- [Qemu-devel] [PATCH v2 11/16] block: qcow2 image file reopen, Jeff Cody, 2012/09/13
- [Qemu-devel] [PATCH v2 16/16] block: remove keep_read_only flag from BlockDriverState struct, Jeff Cody, 2012/09/13
- [Qemu-devel] [PATCH v2 05/16] block: move open flag parsing in raw block drivers to helper functions, Jeff Cody, 2012/09/13
- [Qemu-devel] [PATCH v2 15/16] block: convert bdrv_commit() to use bdrv_reopen(), Jeff Cody, 2012/09/13
- [Qemu-devel] [PATCH v2 14/16] block: raw-win32 driver reopen support,
Jeff Cody <=
- [Qemu-devel] [PATCH v2 12/16] block: qcow image file reopen, Jeff Cody, 2012/09/13
- [Qemu-devel] [PATCH v2 13/16] block: vmdk image file reopen, Jeff Cody, 2012/09/13