diff options
| -rw-r--r-- | block/parallels.c | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/block/parallels.c b/block/parallels.c index 8db64a55e3..e7717c508e 100644 --- a/block/parallels.c +++ b/block/parallels.c @@ -166,7 +166,7 @@ static int64_t block_status(BDRVParallelsState *s, int64_t sector_num, static int64_t allocate_clusters(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum) { - int ret; + int ret = 0; BDRVParallelsState *s = bs->opaque; int64_t pos, space, idx, to_allocate, i, len; @@ -196,14 +196,24 @@ static int64_t allocate_clusters(BlockDriverState *bs, int64_t sector_num, } if (s->data_end + space > (len >> BDRV_SECTOR_BITS)) { space += s->prealloc_size; + /* + * We require the expanded size to read back as zero. If the + * user permitted truncation, we try that; but if it fails, we + * force the safer-but-slower fallocate. + */ + if (s->prealloc_mode == PRL_PREALLOC_MODE_TRUNCATE) { + ret = bdrv_truncate(bs->file, + (s->data_end + space) << BDRV_SECTOR_BITS, + false, PREALLOC_MODE_OFF, BDRV_REQ_ZERO_WRITE, + NULL); + if (ret == -ENOTSUP) { + s->prealloc_mode = PRL_PREALLOC_MODE_FALLOCATE; + } + } if (s->prealloc_mode == PRL_PREALLOC_MODE_FALLOCATE) { ret = bdrv_pwrite_zeroes(bs->file, s->data_end << BDRV_SECTOR_BITS, space << BDRV_SECTOR_BITS, 0); - } else { - ret = bdrv_truncate(bs->file, - (s->data_end + space) << BDRV_SECTOR_BITS, - false, PREALLOC_MODE_OFF, 0, NULL); } if (ret < 0) { return ret; @@ -828,6 +838,7 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags, qemu_opt_get_size_del(opts, PARALLELS_OPT_PREALLOC_SIZE, 0); s->prealloc_size = MAX(s->tracks, s->prealloc_size >> BDRV_SECTOR_BITS); buf = qemu_opt_get_del(opts, PARALLELS_OPT_PREALLOC_MODE); + /* prealloc_mode can be downgraded later during allocate_clusters */ s->prealloc_mode = qapi_enum_parse(&prealloc_mode_lookup, buf, PRL_PREALLOC_MODE_FALLOCATE, &local_err); @@ -836,10 +847,6 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags, goto fail_options; } - if (!bdrv_has_zero_init_truncate(bs->file->bs)) { - s->prealloc_mode = PRL_PREALLOC_MODE_FALLOCATE; - } - if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_INACTIVE)) { s->header->inuse = cpu_to_le32(HEADER_INUSE_MAGIC); ret = parallels_update_header(bs); |