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Re: [Qemu-devel] [PATCH] sanitize ->bdrv_get_buffer / ->bdrv_put_buffer
From: |
Christoph Hellwig |
Subject: |
Re: [Qemu-devel] [PATCH] sanitize ->bdrv_get_buffer / ->bdrv_put_buffer calling conventions |
Date: |
Wed, 8 Jul 2009 16:01:17 +0200 |
User-agent: |
Mutt/1.3.28i |
On Wed, Jul 08, 2009 at 03:46:15PM +0200, Kevin Wolf wrote:
> Christoph Hellwig schrieb:
> > The VM state offset is an concept internal to the image format, it
> > doesn't even have to be a traditional linear offset. So change the
> > ->bdrv_get_buffer / ->bdrv_put_buffer calling convention to always pass
> > a relative offset and add the VM state offset to it internally inside
> > the qcow2 code.
>
> Looks good to me and makes the interface nicer. Maybe we could use the
> opportunity to change the function names to something like
> bdrv_vmstate_read/write? get/put_buffer is quite unspecific, it could
> mean anything.
Does this one looks good?
Index: qemu/savevm.c
===================================================================
--- qemu.orig/savevm.c 2009-07-08 14:01:26.247364595 +0200
+++ qemu/savevm.c 2009-07-08 15:55:24.189365614 +0200
@@ -337,46 +337,28 @@ fail:
return NULL;
}
-typedef struct QEMUFileBdrv
-{
- BlockDriverState *bs;
- int64_t base_offset;
-} QEMUFileBdrv;
-
static int block_put_buffer(void *opaque, const uint8_t *buf,
int64_t pos, int size)
{
- QEMUFileBdrv *s = opaque;
- bdrv_put_buffer(s->bs, buf, s->base_offset + pos, size);
+ bdrv_save_vmstate(opaque, buf, pos, size);
return size;
}
static int block_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
{
- QEMUFileBdrv *s = opaque;
- return bdrv_get_buffer(s->bs, buf, s->base_offset + pos, size);
+ return bdrv_load_vmstate(opaque, buf, pos, size);
}
static int bdrv_fclose(void *opaque)
{
- QEMUFileBdrv *s = opaque;
- qemu_free(s);
return 0;
}
-static QEMUFile *qemu_fopen_bdrv(BlockDriverState *bs, int64_t offset, int
is_writable)
+static QEMUFile *qemu_fopen_bdrv(BlockDriverState *bs, int is_writable)
{
- QEMUFileBdrv *s;
-
- s = qemu_mallocz(sizeof(QEMUFileBdrv));
-
- s->bs = bs;
- s->base_offset = offset;
-
if (is_writable)
- return qemu_fopen_ops(s, block_put_buffer, NULL, bdrv_fclose, NULL,
NULL);
-
- return qemu_fopen_ops(s, NULL, block_get_buffer, bdrv_fclose, NULL, NULL);
+ return qemu_fopen_ops(bs, block_put_buffer, NULL, bdrv_fclose, NULL,
NULL);
+ return qemu_fopen_ops(bs, NULL, block_get_buffer, bdrv_fclose, NULL, NULL);
}
QEMUFile *qemu_fopen_ops(void *opaque, QEMUFilePutBufferFunc *put_buffer,
@@ -1069,7 +1051,6 @@ void do_savevm(Monitor *mon, const char
BlockDriverState *bs, *bs1;
QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1;
int must_delete, ret, i;
- BlockDriverInfo bdi1, *bdi = &bdi1;
QEMUFile *f;
int saved_vm_running;
uint32_t vm_state_size;
@@ -1119,14 +1100,8 @@ void do_savevm(Monitor *mon, const char
#endif
sn->vm_clock_nsec = qemu_get_clock(vm_clock);
- if (bdrv_get_info(bs, bdi) < 0 || bdi->vm_state_offset <= 0) {
- monitor_printf(mon, "Device %s does not support VM state snapshots\n",
- bdrv_get_device_name(bs));
- goto the_end;
- }
-
/* save the VM state */
- f = qemu_fopen_bdrv(bs, bdi->vm_state_offset, 1);
+ f = qemu_fopen_bdrv(bs, 1);
if (!f) {
monitor_printf(mon, "Could not open VM state file\n");
goto the_end;
@@ -1170,7 +1145,6 @@ void do_savevm(Monitor *mon, const char
void do_loadvm(Monitor *mon, const char *name)
{
BlockDriverState *bs, *bs1;
- BlockDriverInfo bdi1, *bdi = &bdi1;
QEMUSnapshotInfo sn;
QEMUFile *f;
int i, ret;
@@ -1218,19 +1192,13 @@ void do_loadvm(Monitor *mon, const char
}
}
- if (bdrv_get_info(bs, bdi) < 0 || bdi->vm_state_offset <= 0) {
- monitor_printf(mon, "Device %s does not support VM state snapshots\n",
- bdrv_get_device_name(bs));
- return;
- }
-
/* Don't even try to load empty VM states */
ret = bdrv_snapshot_find(bs, &sn, name);
if ((ret >= 0) && (sn.vm_state_size == 0))
goto the_end;
/* restore the VM state */
- f = qemu_fopen_bdrv(bs, bdi->vm_state_offset, 0);
+ f = qemu_fopen_bdrv(bs, 0);
if (!f) {
monitor_printf(mon, "Could not open VM state file\n");
goto the_end;
Index: qemu/block/qcow2.c
===================================================================
--- qemu.orig/block/qcow2.c 2009-07-08 14:01:26.254364718 +0200
+++ qemu/block/qcow2.c 2009-07-08 15:56:01.493321620 +0200
@@ -897,12 +897,16 @@ static void qcow_flush(BlockDriverState
bdrv_flush(s->hd);
}
+static int64_t qcow_vm_state_offset(BDRVQcowState *s)
+{
+ return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
+}
+
static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
BDRVQcowState *s = bs->opaque;
bdi->cluster_size = s->cluster_size;
- bdi->vm_state_offset = (int64_t)s->l1_vm_state_index <<
- (s->cluster_bits + s->l2_bits);
+ bdi->vm_state_offset = qcow_vm_state_offset(s);
return 0;
}
@@ -932,26 +936,28 @@ static void dump_refcounts(BlockDriverSt
}
#endif
-static int qcow_put_buffer(BlockDriverState *bs, const uint8_t *buf,
+static int qcow_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
int64_t pos, int size)
{
+ BDRVQcowState *s = bs->opaque;
int growable = bs->growable;
bs->growable = 1;
- bdrv_pwrite(bs, pos, buf, size);
+ bdrv_pwrite(bs, qcow_vm_state_offset(s) + pos, buf, size);
bs->growable = growable;
return size;
}
-static int qcow_get_buffer(BlockDriverState *bs, uint8_t *buf,
+static int qcow_load_vmstate(BlockDriverState *bs, uint8_t *buf,
int64_t pos, int size)
{
+ BDRVQcowState *s = bs->opaque;
int growable = bs->growable;
int ret;
bs->growable = 1;
- ret = bdrv_pread(bs, pos, buf, size);
+ ret = bdrv_pread(bs, qcow_vm_state_offset(s) + pos, buf, size);
bs->growable = growable;
return ret;
@@ -1008,8 +1014,8 @@ static BlockDriver bdrv_qcow2 = {
.bdrv_snapshot_list = qcow2_snapshot_list,
.bdrv_get_info = qcow_get_info,
- .bdrv_put_buffer = qcow_put_buffer,
- .bdrv_get_buffer = qcow_get_buffer,
+ .bdrv_save_vmstate = qcow_save_vmstate,
+ .bdrv_load_vmstate = qcow_load_vmstate,
.create_options = qcow_create_options,
.bdrv_check = qcow_check,
Index: qemu/block.c
===================================================================
--- qemu.orig/block.c 2009-07-08 15:53:02.225364220 +0200
+++ qemu/block.c 2009-07-08 15:55:33.728367200 +0200
@@ -1165,24 +1165,26 @@ int bdrv_get_info(BlockDriverState *bs,
return drv->bdrv_get_info(bs, bdi);
}
-int bdrv_put_buffer(BlockDriverState *bs, const uint8_t *buf, int64_t pos, int
size)
+int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
+ int64_t pos, int size)
{
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
- if (!drv->bdrv_put_buffer)
+ if (!drv->bdrv_save_vmstate)
return -ENOTSUP;
- return drv->bdrv_put_buffer(bs, buf, pos, size);
+ return drv->bdrv_save_vmstate(bs, buf, pos, size);
}
-int bdrv_get_buffer(BlockDriverState *bs, uint8_t *buf, int64_t pos, int size)
+int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
+ int64_t pos, int size)
{
BlockDriver *drv = bs->drv;
if (!drv)
return -ENOMEDIUM;
- if (!drv->bdrv_get_buffer)
+ if (!drv->bdrv_load_vmstate)
return -ENOTSUP;
- return drv->bdrv_get_buffer(bs, buf, pos, size);
+ return drv->bdrv_load_vmstate(bs, buf, pos, size);
}
/**************************************************************/
Index: qemu/block.h
===================================================================
--- qemu.orig/block.h 2009-07-08 15:53:02.239364323 +0200
+++ qemu/block.h 2009-07-08 15:54:51.983241775 +0200
@@ -162,9 +162,10 @@ void path_combine(char *dest, int dest_s
const char *base_path,
const char *filename);
-int bdrv_put_buffer(BlockDriverState *bs, const uint8_t *buf,
- int64_t pos, int size);
+int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
+ int64_t pos, int size);
-int bdrv_get_buffer(BlockDriverState *bs, uint8_t *buf, int64_t pos, int size);
+int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
+ int64_t pos, int size);
#endif
Index: qemu/block_int.h
===================================================================
--- qemu.orig/block_int.h 2009-07-08 15:53:02.254364553 +0200
+++ qemu/block_int.h 2009-07-08 15:55:14.827454532 +0200
@@ -84,10 +84,10 @@ struct BlockDriver {
QEMUSnapshotInfo **psn_info);
int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi);
- int (*bdrv_put_buffer)(BlockDriverState *bs, const uint8_t *buf,
- int64_t pos, int size);
- int (*bdrv_get_buffer)(BlockDriverState *bs, uint8_t *buf,
- int64_t pos, int size);
+ int (*bdrv_save_vmstate)(BlockDriverState *bs, const uint8_t *buf,
+ int64_t pos, int size);
+ int (*bdrv_load_vmstate)(BlockDriverState *bs, uint8_t *buf,
+ int64_t pos, int size);
/* removable device specific */
int (*bdrv_is_inserted)(BlockDriverState *bs);