From 522e07cf4d68cd672bbaad7a4f7759dd447e9614 Mon Sep 17 00:00:00 2001 Message-Id: <522e07cf4d68cd672bbaad7a4f7759dd447e9614.1379425497.git.minovotn@redhat.com> In-Reply-To: References: From: Kevin Wolf Date: Fri, 6 Sep 2013 18:12:26 +0200 Subject: [PATCH 06/25] 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 (cherry picked from commit b0ad5a455d7e5352d4c86ba945112011dbeadfb8) Signed-off-by: Michal Novotny --- block/cow.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/block/cow.c b/block/cow.c index 05d6448..8820f84 100644 --- a/block/cow.c +++ b/block/cow.c @@ -110,17 +110,18 @@ 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; } @@ -129,10 +130,11 @@ 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))); -- 1.7.11.7