diff options
Diffstat (limited to 'block/cow.c')
| -rw-r--r-- | block/cow.c | 92 |
1 files changed, 52 insertions, 40 deletions
diff --git a/block/cow.c b/block/cow.c index 089d395c40..bb5927c6aa 100644 --- a/block/cow.c +++ b/block/cow.c @@ -64,15 +64,26 @@ static int cow_open(BlockDriverState *bs, int flags) struct cow_header_v2 cow_header; int bitmap_size; int64_t size; + int ret; /* see if it is a cow image */ - if (bdrv_pread(bs->file, 0, &cow_header, sizeof(cow_header)) != - sizeof(cow_header)) { + ret = bdrv_pread(bs->file, 0, &cow_header, sizeof(cow_header)); + if (ret < 0) { + goto fail; + } + + if (be32_to_cpu(cow_header.magic) != COW_MAGIC) { + ret = -EINVAL; goto fail; } - if (be32_to_cpu(cow_header.magic) != COW_MAGIC || - be32_to_cpu(cow_header.version) != COW_VERSION) { + if (be32_to_cpu(cow_header.version) != COW_VERSION) { + char version[64]; + snprintf(version, sizeof(version), + "COW version %d", cow_header.version); + qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, + bs->device_name, "cow", version); + ret = -ENOTSUP; goto fail; } @@ -88,11 +99,11 @@ static int cow_open(BlockDriverState *bs, int flags) qemu_co_mutex_init(&s->lock); return 0; fail: - return -1; + return ret; } /* - * XXX(hch): right now these functions are extremly ineffcient. + * XXX(hch): right now these functions are extremely ineffcient. * We should just read the whole bitmap we'll need in one go instead. */ static inline int cow_set_bit(BlockDriverState *bs, int64_t bitnum) @@ -132,8 +143,8 @@ static inline int is_bit_set(BlockDriverState *bs, int64_t bitnum) /* Return true if first block has been changed (ie. current version is * in COW file). Set the number of continuous blocks for which that * is true. */ -static int cow_is_allocated(BlockDriverState *bs, int64_t sector_num, - int nb_sectors, int *num_same) +static int coroutine_fn cow_co_is_allocated(BlockDriverState *bs, + int64_t sector_num, int nb_sectors, int *num_same) { int changed; @@ -171,28 +182,30 @@ static int cow_update_bitmap(BlockDriverState *bs, int64_t sector_num, return error; } -static int cow_read(BlockDriverState *bs, int64_t sector_num, - uint8_t *buf, int nb_sectors) +static int coroutine_fn cow_read(BlockDriverState *bs, int64_t sector_num, + uint8_t *buf, int nb_sectors) { BDRVCowState *s = bs->opaque; int ret, n; while (nb_sectors > 0) { - if (cow_is_allocated(bs, sector_num, nb_sectors, &n)) { + if (bdrv_co_is_allocated(bs, sector_num, nb_sectors, &n)) { ret = bdrv_pread(bs->file, s->cow_sectors_offset + sector_num * 512, buf, n * 512); - if (ret != n * 512) - return -1; + if (ret < 0) { + return ret; + } } else { if (bs->backing_hd) { /* read from the base image */ ret = bdrv_read(bs->backing_hd, sector_num, buf, n); - if (ret < 0) - return -1; + if (ret < 0) { + return ret; + } } else { - memset(buf, 0, n * 512); - } + memset(buf, 0, n * 512); + } } nb_sectors -= n; sector_num += n; @@ -220,8 +233,9 @@ static int cow_write(BlockDriverState *bs, int64_t sector_num, ret = bdrv_pwrite(bs->file, s->cow_sectors_offset + sector_num * 512, buf, nb_sectors * 512); - if (ret != nb_sectors * 512) - return -1; + if (ret < 0) { + return ret; + } return cow_update_bitmap(bs, sector_num, nb_sectors); } @@ -243,12 +257,12 @@ static void cow_close(BlockDriverState *bs) static int cow_create(const char *filename, QEMUOptionParameter *options) { - int fd, cow_fd; struct cow_header_v2 cow_header; struct stat st; int64_t image_sectors = 0; const char *image_filename = NULL; int ret; + BlockDriverState *cow_bs; /* Read out options */ while (options && options->name) { @@ -260,10 +274,16 @@ static int cow_create(const char *filename, QEMUOptionParameter *options) options++; } - cow_fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, - 0644); - if (cow_fd < 0) - return -errno; + ret = bdrv_create_file(filename, options); + if (ret < 0) { + return ret; + } + + ret = bdrv_file_open(&cow_bs, filename, BDRV_O_RDWR); + if (ret < 0) { + return ret; + } + memset(&cow_header, 0, sizeof(cow_header)); cow_header.magic = cpu_to_be32(COW_MAGIC); cow_header.version = cpu_to_be32(COW_VERSION); @@ -271,16 +291,9 @@ static int cow_create(const char *filename, QEMUOptionParameter *options) /* Note: if no file, we put a dummy mtime */ cow_header.mtime = cpu_to_be32(0); - fd = open(image_filename, O_RDONLY | O_BINARY); - if (fd < 0) { - close(cow_fd); + if (stat(image_filename, &st) != 0) { goto mtime_fail; } - if (fstat(fd, &st) != 0) { - close(fd); - goto mtime_fail; - } - close(fd); cow_header.mtime = cpu_to_be32(st.st_mtime); mtime_fail: pstrcpy(cow_header.backing_file, sizeof(cow_header.backing_file), @@ -288,21 +301,20 @@ static int cow_create(const char *filename, QEMUOptionParameter *options) } cow_header.sectorsize = cpu_to_be32(512); cow_header.size = cpu_to_be64(image_sectors * 512); - ret = qemu_write_full(cow_fd, &cow_header, sizeof(cow_header)); - if (ret != sizeof(cow_header)) { - ret = -errno; + ret = bdrv_pwrite(cow_bs, 0, &cow_header, sizeof(cow_header)); + if (ret < 0) { goto exit; } /* resize to include at least all the bitmap */ - ret = ftruncate(cow_fd, sizeof(cow_header) + ((image_sectors + 7) >> 3)); - if (ret) { - ret = -errno; + ret = bdrv_truncate(cow_bs, + sizeof(cow_header) + ((image_sectors + 7) >> 3)); + if (ret < 0) { goto exit; } exit: - close(cow_fd); + bdrv_delete(cow_bs); return ret; } @@ -337,7 +349,7 @@ static BlockDriver bdrv_cow = { .bdrv_read = cow_co_read, .bdrv_write = cow_co_write, .bdrv_co_flush_to_disk = cow_co_flush, - .bdrv_is_allocated = cow_is_allocated, + .bdrv_co_is_allocated = cow_co_is_allocated, .create_options = cow_create_options, }; |