From cbaccf5d53412a1ae93b18c91d2cbf36058e5cf5 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 14 Feb 2012 11:13:41 +0100 Subject: [PATCH 16/99] cow: use qemu block API RH-Author: Kevin Wolf Message-id: <1329218101-24213-17-git-send-email-kwolf@redhat.com> Patchwork-id: 37209 O-Subject: [RHEL-6.3 qemu-kvm PATCH v2 16/96] cow: use qemu block API Bugzilla: 783950 RH-Acked-by: Paolo Bonzini RH-Acked-by: Marcelo Tosatti RH-Acked-by: Laszlo Ersek From: Christoph Hellwig Bugzilla: 783950 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 Signed-off-by: Kevin Wolf (cherry picked from commit 2063392ae5d00a9ea13039f971e2b9e61bd68dbc) Conflicts: block/cow.c Signed-off-by: Kevin Wolf --- block/cow.c | 39 +++++++++++++-------------------------- 1 files changed, 13 insertions(+), 26 deletions(-) Signed-off-by: Michal Novotny --- block/cow.c | 39 +++++++++++++-------------------------- 1 files changed, 13 insertions(+), 26 deletions(-) diff --git a/block/cow.c b/block/cow.c index aadbec2..799569c 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 int cow_flush(BlockDriverState *bs) { - BDRVCowState *s = bs->opaque; - return qemu_fdatasync(s->fd); + return 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, -- 1.7.7.5