[Qemu-devel] [7005] Fix savevm after BDRV_FILE size enforcement

[Qemu-devel] [7005] Fix savevm after BDRV_FILE size enforcement

[Anthony Liguori]

Revision: 7005
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=7005
Author:   aliguori
Date:     2009-04-05 21:07:26 +0000 (Sun, 05 Apr 2009)
Log Message:
-----------
 Fix savevm after BDRV_FILE size enforcement
 
 We now enforce that you cannot write beyond the end of a non-growable file.
 qcow2 files are not growable but we rely on them being growable to do
 savevm/loadvm.  Temporarily allow them to be growable by introducing a new
 API specifically for savevm read/write operations.
 
 Reported-by: malc
 Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
 

Modified Paths:
--------------
    branches/stable_0_10/block-qcow2.c
    branches/stable_0_10/block.c
    branches/stable_0_10/block.h
    branches/stable_0_10/block_int.h
    branches/stable_0_10/savevm.c

Modified: branches/stable_0_10/block-qcow2.c
===================================================================
--- branches/stable_0_10/block-qcow2.c	2009-04-05 20:08:59 UTC (rev 7004)
+++ branches/stable_0_10/block-qcow2.c	2009-04-05 21:07:26 UTC (rev 7005)
@@ -2601,6 +2601,31 @@
 #endif
 #endif
 
+static int qcow_put_buffer(BlockDriverState *bs, const uint8_t *buf,
+                           int64_t pos, int size)
+{
+    int growable = bs->growable;
+
+    bs->growable = 1;
+    bdrv_pwrite(bs, pos, buf, size);
+    bs->growable = growable;
+
+    return size;
+}
+
+static int qcow_get_buffer(BlockDriverState *bs, uint8_t *buf,
+                           int64_t pos, int size)
+{
+    int growable = bs->growable;
+    int ret;
+
+    bs->growable = 1;
+    ret = bdrv_pread(bs, pos, buf, size);
+    bs->growable = growable;
+
+    return ret;
+}
+
 BlockDriver bdrv_qcow2 = {
     "qcow2",
     sizeof(BDRVQcowState),
@@ -2626,4 +2651,7 @@
     .bdrv_snapshot_delete = qcow_snapshot_delete,
     .bdrv_snapshot_list = qcow_snapshot_list,
     .bdrv_get_info = qcow_get_info,
+
+    .bdrv_put_buffer    = qcow_put_buffer,
+    .bdrv_get_buffer    = qcow_get_buffer,
 };

Modified: branches/stable_0_10/block.c
===================================================================
--- branches/stable_0_10/block.c	2009-04-05 20:08:59 UTC (rev 7004)
+++ branches/stable_0_10/block.c	2009-04-05 21:07:26 UTC (rev 7005)
@@ -1181,6 +1181,26 @@
     return drv->bdrv_get_info(bs, bdi);
 }
 
+int bdrv_put_buffer(BlockDriverState *bs, const uint8_t *buf, int64_t pos, int size)
+{
+    BlockDriver *drv = bs->drv;
+    if (!drv)
+        return -ENOMEDIUM;
+    if (!drv->bdrv_put_buffer)
+        return -ENOTSUP;
+    return drv->bdrv_put_buffer(bs, buf, pos, size);
+}
+
+int bdrv_get_buffer(BlockDriverState *bs, uint8_t *buf, int64_t pos, int size)
+{
+    BlockDriver *drv = bs->drv;
+    if (!drv)
+        return -ENOMEDIUM;
+    if (!drv->bdrv_get_buffer)
+        return -ENOTSUP;
+    return drv->bdrv_get_buffer(bs, buf, pos, size);
+}
+
 /**************************************************************/
 /* handling of snapshots */
 

Modified: branches/stable_0_10/block.h
===================================================================
--- branches/stable_0_10/block.h	2009-04-05 20:08:59 UTC (rev 7004)
+++ branches/stable_0_10/block.h	2009-04-05 21:07:26 UTC (rev 7005)
@@ -169,4 +169,9 @@
                   const char *base_path,
                   const char *filename);
 
+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);
+
 #endif

Modified: branches/stable_0_10/block_int.h
===================================================================
--- branches/stable_0_10/block_int.h	2009-04-05 20:08:59 UTC (rev 7004)
+++ branches/stable_0_10/block_int.h	2009-04-05 21:07:26 UTC (rev 7005)
@@ -76,6 +76,11 @@
                               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);
+
     /* removable device specific */
     int (*bdrv_is_inserted)(BlockDriverState *bs);
     int (*bdrv_media_changed)(BlockDriverState *bs);

Modified: branches/stable_0_10/savevm.c
===================================================================
--- branches/stable_0_10/savevm.c	2009-04-05 20:08:59 UTC (rev 7004)
+++ branches/stable_0_10/savevm.c	2009-04-05 21:07:26 UTC (rev 7005)
@@ -306,18 +306,18 @@
     int64_t base_offset;
 } QEMUFileBdrv;
 
-static int bdrv_put_buffer(void *opaque, const uint8_t *buf,
+static int block_put_buffer(void *opaque, const uint8_t *buf,
                            int64_t pos, int size)
 {
     QEMUFileBdrv *s = opaque;
-    bdrv_pwrite(s->bs, s->base_offset + pos, buf, size);
+    bdrv_put_buffer(s->bs, buf, s->base_offset + pos, size);
     return size;
 }
 
-static int bdrv_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
+static int block_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)
 {
     QEMUFileBdrv *s = opaque;
-    return bdrv_pread(s->bs, s->base_offset + pos, buf, size);
+    return bdrv_get_buffer(s->bs, buf, s->base_offset + pos, size);
 }
 
 static int bdrv_fclose(void *opaque)
@@ -337,9 +337,9 @@
     s->base_offset = offset;
 
     if (is_writable)
-        return qemu_fopen_ops(s, bdrv_put_buffer, NULL, bdrv_fclose, NULL);
+        return qemu_fopen_ops(s, block_put_buffer, NULL, bdrv_fclose, NULL);
 
-    return qemu_fopen_ops(s, NULL, bdrv_get_buffer, bdrv_fclose, NULL);
+    return qemu_fopen_ops(s, NULL, block_get_buffer, bdrv_fclose, NULL);
 }
 
 QEMUFile *qemu_fopen_ops(void *opaque, QEMUFilePutBufferFunc *put_buffer,