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[Qemu-devel] [PATCH 10/19] cow: use qemu block API
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 10/19] cow: use qemu block API |
Date: |
Tue, 15 Jun 2010 16:19:32 +0200 |
From: Christoph Hellwig <address@hidden>
Use bdrv_pwrite to access the backing device instead of pread, and
convert the driver to implementing the bdrv_open method which gives
it an already opened BlockDriverState for the underlying device.
Signed-off-by: Christoph Hellwig <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
block/cow.c | 39 +++++++++++++--------------------------
1 files changed, 13 insertions(+), 26 deletions(-)
diff --git a/block/cow.c b/block/cow.c
index ec9a9f7..d146434 100644
--- a/block/cow.c
+++ b/block/cow.c
@@ -42,7 +42,6 @@ struct cow_header_v2 {
};
typedef struct BDRVCowState {
- int fd;
int64_t cow_sectors_offset;
} BDRVCowState;
@@ -58,23 +57,16 @@ static int cow_probe(const uint8_t *buf, int buf_size,
const char *filename)
return 0;
}
-static int cow_open(BlockDriverState *bs, const char *filename, int flags)
+static int cow_open(BlockDriverState *bs, int flags)
{
BDRVCowState *s = bs->opaque;
- int fd;
struct cow_header_v2 cow_header;
int bitmap_size;
int64_t size;
- fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
- if (fd < 0) {
- fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
- if (fd < 0)
- return -1;
- }
- s->fd = fd;
/* see if it is a cow image */
- if (pread(fd, &cow_header, sizeof(cow_header), 0) != sizeof(cow_header)) {
+ if (bdrv_pread(bs->file, 0, &cow_header, sizeof(cow_header)) !=
+ sizeof(cow_header)) {
goto fail;
}
@@ -94,7 +86,6 @@ static int cow_open(BlockDriverState *bs, const char
*filename, int flags)
s->cow_sectors_offset = (bitmap_size + 511) & ~511;
return 0;
fail:
- close(fd);
return -1;
}
@@ -104,18 +95,17 @@ static int cow_open(BlockDriverState *bs, const char
*filename, int flags)
*/
static inline int cow_set_bit(BlockDriverState *bs, int64_t bitnum)
{
- BDRVCowState *s = bs->opaque;
uint64_t offset = sizeof(struct cow_header_v2) + bitnum / 8;
uint8_t bitmap;
- if (pread(s->fd, &bitmap, sizeof(bitmap), offset) !=
+ if (bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap)) !=
sizeof(bitmap)) {
return -errno;
}
bitmap |= (1 << (bitnum % 8));
- if (pwrite(s->fd, &bitmap, sizeof(bitmap), offset) !=
+ if (bdrv_pwrite(bs->file, offset, &bitmap, sizeof(bitmap)) !=
sizeof(bitmap)) {
return -errno;
}
@@ -124,11 +114,10 @@ static inline int cow_set_bit(BlockDriverState *bs,
int64_t bitnum)
static inline int is_bit_set(BlockDriverState *bs, int64_t bitnum)
{
- BDRVCowState *s = bs->opaque;
uint64_t offset = sizeof(struct cow_header_v2) + bitnum / 8;
uint8_t bitmap;
- if (pread(s->fd, &bitmap, sizeof(bitmap), offset) !=
+ if (bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap)) !=
sizeof(bitmap)) {
return -errno;
}
@@ -186,8 +175,9 @@ static int cow_read(BlockDriverState *bs, int64_t
sector_num,
while (nb_sectors > 0) {
if (cow_is_allocated(bs, sector_num, nb_sectors, &n)) {
- ret = pread(s->fd, buf, n * 512,
- s->cow_sectors_offset + sector_num * 512);
+ ret = bdrv_pread(bs->file,
+ s->cow_sectors_offset + sector_num * 512,
+ buf, n * 512);
if (ret != n * 512)
return -1;
} else {
@@ -213,8 +203,8 @@ static int cow_write(BlockDriverState *bs, int64_t
sector_num,
BDRVCowState *s = bs->opaque;
int ret;
- ret = pwrite(s->fd, buf, nb_sectors * 512,
- s->cow_sectors_offset + sector_num * 512);
+ ret = bdrv_pwrite(bs->file, s->cow_sectors_offset + sector_num * 512,
+ buf, nb_sectors * 512);
if (ret != nb_sectors * 512)
return -1;
@@ -223,8 +213,6 @@ static int cow_write(BlockDriverState *bs, int64_t
sector_num,
static void cow_close(BlockDriverState *bs)
{
- BDRVCowState *s = bs->opaque;
- close(s->fd);
}
static int cow_create(const char *filename, QEMUOptionParameter *options)
@@ -294,8 +282,7 @@ exit:
static void cow_flush(BlockDriverState *bs)
{
- BDRVCowState *s = bs->opaque;
- qemu_fdatasync(s->fd);
+ bdrv_flush(bs->file);
}
static QEMUOptionParameter cow_create_options[] = {
@@ -316,7 +303,7 @@ static BlockDriver bdrv_cow = {
.format_name = "cow",
.instance_size = sizeof(BDRVCowState),
.bdrv_probe = cow_probe,
- .bdrv_file_open = cow_open,
+ .bdrv_open = cow_open,
.bdrv_read = cow_read,
.bdrv_write = cow_write,
.bdrv_close = cow_close,
--
1.6.6.1
- [Qemu-devel] [PULL 00/19] Block patches, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 01/19] vpc: Read/write multiple sectors at once, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 03/19] qcow2: Allow alloc_clusters_noref to return errors, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 02/19] qcow2: Allow get_refcount to return errors, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 04/19] qcow2: Return real error code in load_refcount_block, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 05/19] savevm: Really verify if a drive supports snapshots, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 07/19] qcow2: Restore L1 entry on l2_allocate failure, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 08/19] cow: use pread/pwrite, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 06/19] Fix regression for "-drive file=", Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 10/19] cow: use qemu block API,
Kevin Wolf <=
- [Qemu-devel] [PATCH 14/19] block: New bdrv_next(), Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 12/19] block: Decouple block device "commit all" from DriveInfo, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 13/19] monitor: Make "commit FOO" complain when FOO doesn't exist, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 11/19] block: Move error actions from DriveInfo to BlockDriverState, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 15/19] block: Decouple savevm from DriveInfo, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 09/19] cow: stop using mmap, Kevin Wolf, 2010/06/15
- [Qemu-devel] [PATCH 17/19] Correct definitions for FD_CMD_SAVE and FD_CMD_RESTORE, Kevin Wolf, 2010/06/15