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[Qemu-devel] [RFC 2/6] block: add bdrv_set_copy_on_read()
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [RFC 2/6] block: add bdrv_set_copy_on_read() |
Date: |
Mon, 17 Oct 2011 16:47:28 +0100 |
The bdrv_set_copy_on_read() function can be used to programmatically
enable or disable copy-on-read for a block device. Later patches add
the actual copy-on-read logic.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
block.c | 17 +++++++++++++++++
block.h | 3 +++
block_int.h | 1 +
3 files changed, 21 insertions(+), 0 deletions(-)
diff --git a/block.c b/block.c
index 2d2c62a..e624ac3 100644
--- a/block.c
+++ b/block.c
@@ -464,6 +464,18 @@ int bdrv_parse_cache_flags(const char *mode, int *flags)
return 0;
}
+void bdrv_set_copy_on_read(BlockDriverState *bs, int enable)
+{
+ if (bs->copy_on_read != enable) {
+ if (enable) {
+ bdrv_start_request_tracking(bs);
+ } else {
+ bdrv_stop_request_tracking(bs);
+ }
+ }
+ bs->copy_on_read = enable;
+}
+
/*
* Common part for opening disk images and files
*/
@@ -483,6 +495,11 @@ static int bdrv_open_common(BlockDriverState *bs, const
char *filename,
bs->open_flags = flags;
bs->buffer_alignment = 512;
+ bs->copy_on_read = 0;
+ if (flags & BDRV_O_RDWR) {
+ bdrv_set_copy_on_read(bs, !!(flags & BDRV_O_COPY_ON_READ));
+ }
+
pstrcpy(bs->filename, sizeof(bs->filename), filename);
if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv)) {
diff --git a/block.h b/block.h
index e77988e..cb9832c 100644
--- a/block.h
+++ b/block.h
@@ -61,6 +61,7 @@ typedef struct BlockDevOps {
#define BDRV_O_NATIVE_AIO 0x0080 /* use native AIO instead of the thread pool
*/
#define BDRV_O_NO_BACKING 0x0100 /* don't open the backing file */
#define BDRV_O_NO_FLUSH 0x0200 /* disable flushing on this disk */
+#define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */
#define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH)
@@ -291,6 +292,8 @@ void bdrv_reset_dirty(BlockDriverState *bs, int64_t
cur_sector,
int nr_sectors);
int64_t bdrv_get_dirty_count(BlockDriverState *bs);
+void bdrv_set_copy_on_read(BlockDriverState *bs, int enable);
+
void bdrv_set_in_use(BlockDriverState *bs, int in_use);
int bdrv_in_use(BlockDriverState *bs);
diff --git a/block_int.h b/block_int.h
index 87ce8b4..8eb4795 100644
--- a/block_int.h
+++ b/block_int.h
@@ -160,6 +160,7 @@ struct BlockDriverState {
int encrypted; /* if true, the media is encrypted */
int valid_key; /* if true, a valid encryption key has been set */
int sg; /* if true, the device is a /dev/sg* */
+ int copy_on_read; /* if true, copy read backing sectors into image */
BlockDriver *drv; /* NULL means no media */
void *opaque;
--
1.7.6.3
- [Qemu-devel] [RFC 0/6] block: generic copy-on-read, Stefan Hajnoczi, 2011/10/17
- [Qemu-devel] [RFC 5/6] block: core copy-on-read logic, Stefan Hajnoczi, 2011/10/17
- [Qemu-devel] [RFC 3/6] block: wait for overlapping requests, Stefan Hajnoczi, 2011/10/17
- [Qemu-devel] [RFC 1/6] block: add request tracking, Stefan Hajnoczi, 2011/10/17
- [Qemu-devel] [RFC 2/6] block: add bdrv_set_copy_on_read(),
Stefan Hajnoczi <=
- [Qemu-devel] [RFC 6/6] block: add -drive copy-on-read=on|off, Stefan Hajnoczi, 2011/10/17
- [Qemu-devel] [RFC 4/6] block: request overlap detection, Stefan Hajnoczi, 2011/10/17