diff options
| -rw-r--r-- | block/qcow2.c | 81 | ||||
| -rw-r--r-- | block_int.h | 1 |
2 files changed, 80 insertions, 2 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index a5bf20522d..a9c39bd817 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -638,9 +638,54 @@ static int get_bits_from_size(size_t size) return res; } + +static int preallocate(BlockDriverState *bs) +{ + BDRVQcowState *s = bs->opaque; + uint64_t cluster_offset; + uint64_t nb_sectors; + uint64_t offset; + int num; + QCowL2Meta meta; + + nb_sectors = bdrv_getlength(bs) >> 9; + offset = 0; + + while (nb_sectors) { + num = MIN(nb_sectors, INT_MAX >> 9); + cluster_offset = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num, + &meta); + + if (cluster_offset == 0) { + return -1; + } + + if (qcow2_alloc_cluster_link_l2(bs, cluster_offset, &meta) < 0) { + qcow2_free_any_clusters(bs, cluster_offset, meta.nb_clusters); + return -1; + } + + /* TODO Preallocate data if requested */ + + nb_sectors -= num; + offset += num << 9; + } + + /* + * It is expected that the image file is large enough to actually contain + * all of the allocated clusters (otherwise we get failing reads after + * EOF). Extend the image to the last allocated sector. + */ + if (cluster_offset != 0) { + bdrv_truncate(s->hd, cluster_offset + (num << 9)); + } + + return 0; +} + static int qcow_create2(const char *filename, int64_t total_size, const char *backing_file, const char *backing_format, - int flags, size_t cluster_size) + int flags, size_t cluster_size, int prealloc) { int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits; @@ -762,6 +807,16 @@ static int qcow_create2(const char *filename, int64_t total_size, qemu_free(s->refcount_table); qemu_free(s->refcount_block); close(fd); + + /* Preallocate metadata */ + if (prealloc) { + BlockDriverState *bs; + bs = bdrv_new(""); + bdrv_open(bs, filename, BDRV_O_CACHE_WB); + preallocate(bs); + bdrv_close(bs); + } + return 0; } @@ -772,6 +827,7 @@ static int qcow_create(const char *filename, QEMUOptionParameter *options) uint64_t sectors = 0; int flags = 0; size_t cluster_size = 65536; + int prealloc = 0; /* Read out options */ while (options && options->name) { @@ -787,12 +843,28 @@ static int qcow_create(const char *filename, QEMUOptionParameter *options) if (options->value.n) { cluster_size = options->value.n; } + } else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) { + if (!options->value.s || !strcmp(options->value.s, "off")) { + prealloc = 0; + } else if (!strcmp(options->value.s, "metadata")) { + prealloc = 1; + } else { + fprintf(stderr, "Invalid preallocation mode: '%s'\n", + options->value.s); + return -EINVAL; + } } options++; } + if (backing_file && prealloc) { + fprintf(stderr, "Backing file and preallocation cannot be used at " + "the same time\n"); + return -EINVAL; + } + return qcow_create2(filename, sectors, backing_file, backing_fmt, flags, - cluster_size); + cluster_size, prealloc); } static int qcow_make_empty(BlockDriverState *bs) @@ -982,6 +1054,11 @@ static QEMUOptionParameter qcow_create_options[] = { .type = OPT_SIZE, .help = "qcow2 cluster size" }, + { + .name = BLOCK_OPT_PREALLOC, + .type = OPT_STRING, + .help = "Preallocation mode (allowed values: off, metadata)" + }, { NULL } }; diff --git a/block_int.h b/block_int.h index 8898d91f42..0902fd4733 100644 --- a/block_int.h +++ b/block_int.h @@ -37,6 +37,7 @@ #define BLOCK_OPT_BACKING_FILE "backing_file" #define BLOCK_OPT_BACKING_FMT "backing_fmt" #define BLOCK_OPT_CLUSTER_SIZE "cluster_size" +#define BLOCK_OPT_PREALLOC "preallocation" typedef struct AIOPool { void (*cancel)(BlockDriverAIOCB *acb); |