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cow: Use bdrv_(p)write_sync for metadata writes 

Use bdrv_(p)write_sync to ensure metadata integrity in case of a crash.
While at it, correct the wrong usage of errno.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2010-06-18 16:31:14 +02:00
parent f08145fe16
commit b0ad5a455d
1 changed files with 11 additions and 9 deletions
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20
block/cow.c
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@ -97,17 +97,18 @@ static inline int cow_set_bit(BlockDriverState *bs, int64_t bitnum)
{
uint64_t offset = sizeof(struct cow_header_v2) + bitnum / 8;
uint8_t bitmap;
int ret;
if (bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap)) !=
sizeof(bitmap)) {
return -errno;
ret = bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap));
if (ret < 0) {
return ret;
}
bitmap |= (1 << (bitnum % 8));
if (bdrv_pwrite(bs->file, offset, &bitmap, sizeof(bitmap)) !=
sizeof(bitmap)) {
return -errno;
ret = bdrv_pwrite_sync(bs->file, offset, &bitmap, sizeof(bitmap));
if (ret < 0) {
return ret;
}
return 0;
}
@ -116,10 +117,11 @@ static inline int is_bit_set(BlockDriverState *bs, int64_t bitnum)
{
uint64_t offset = sizeof(struct cow_header_v2) + bitnum / 8;
uint8_t bitmap;
int ret;
if (bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap)) !=
sizeof(bitmap)) {
return -errno;
ret = bdrv_pread(bs->file, offset, &bitmap, sizeof(bitmap));
if (ret < 0) {
return ret;
}
return !!(bitmap & (1 << (bitnum % 8)));