blktap: Allow creation of qcow2 files.

Signed-off-by: Yang Zhang <yang.zhang@intel.com>

3 files changed, 105 insertions, 7 deletions

diff --git a/tools/blktap/drivers/block-qcow2.c b/tools/blktap/drivers/block-qcow2.c
index 8bdd33ea37..744022697c 100644
--- a/tools/blktap/drivers/block-qcow2.c
+++ b/tools/blktap/drivers/block-qcow2.c
@@ -1980,6 +1980,91 @@ static int qcow_validate_parent(struct disk_driver *child,
 	return 0;
 }
 
+int qcow2_create(const char *filename, uint64_t total_size,
+                      const char *backing_file, int flags)
+{
+    int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
+    QCowHeader header;
+    uint64_t tmp, offset;
+    QCowCreateState s1, *s = &s1;
+
+    memset(s, 0, sizeof(*s));
+
+    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
+    if (fd < 0)
+        return -1;
+    memset(&header, 0, sizeof(header));
+    header.magic = cpu_to_be32(QCOW_MAGIC);
+    header.version = cpu_to_be32(QCOW_VERSION);
+    header.size = cpu_to_be64(total_size * 512);
+    header_size = sizeof(header);
+    backing_filename_len = 0;
+    if (backing_file) {
+        header.backing_file_offset = cpu_to_be64(header_size);
+        backing_filename_len = strlen(backing_file);
+        header.backing_file_size = cpu_to_be32(backing_filename_len);
+        header_size += backing_filename_len;
+    }
+    s->cluster_bits = 12;  /* 4 KB clusters */
+    s->cluster_size = 1 << s->cluster_bits;
+    header.cluster_bits = cpu_to_be32(s->cluster_bits);
+    header_size = (header_size + 7) & ~7;
+    if (flags & BLOCK_FLAG_ENCRYPT) {
+        header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
+    } else {
+        header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
+    }
+    l2_bits = s->cluster_bits - 3;
+    shift = s->cluster_bits + l2_bits;
+    l1_size = (((total_size * 512) + (1LL << shift) - 1) >> shift);
+    offset = align_offset(header_size, s->cluster_size);
+    s->l1_table_offset = offset;
+    header.l1_table_offset = cpu_to_be64(s->l1_table_offset);
+    header.l1_size = cpu_to_be32(l1_size);
+    offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size);
+
+    s->refcount_table = qemu_mallocz(s->cluster_size);
+    s->refcount_block = qemu_mallocz(s->cluster_size);
+
+    s->refcount_table_offset = offset;
+    header.refcount_table_offset = cpu_to_be64(offset);
+    header.refcount_table_clusters = cpu_to_be32(1);
+    offset += s->cluster_size;
+
+    s->refcount_table[0] = cpu_to_be64(offset);
+    s->refcount_block_offset = offset;
+    offset += s->cluster_size;
+
+    /* update refcounts */
+    create_refcount_update(s, 0, header_size);
+    create_refcount_update(s, s->l1_table_offset, l1_size * sizeof(uint64_t));
+    create_refcount_update(s, s->refcount_table_offset, s->cluster_size);
+    create_refcount_update(s, s->refcount_block_offset, s->cluster_size);
+
+    /* write all the data */
+    write(fd, &header, sizeof(header));
+    if (backing_file) {
+        write(fd, backing_file, backing_filename_len);
+    }
+    lseek(fd, s->l1_table_offset, SEEK_SET);
+    tmp = 0;
+    for(i = 0;i < l1_size; i++) {
+        write(fd, &tmp, sizeof(tmp));
+    }
+    lseek(fd, s->refcount_table_offset, SEEK_SET);
+    write(fd, s->refcount_table, s->cluster_size);
+
+    lseek(fd, s->refcount_block_offset, SEEK_SET);
+    write(fd, s->refcount_block, s->cluster_size);
+
+    qemu_free(s->refcount_table);
+    qemu_free(s->refcount_block);
+    close(fd);
+    return 0;
+}
+
+
+
 struct tap_disk tapdisk_qcow2 = {
 	"qcow2",
 	sizeof(BDRVQcowState),
diff --git a/tools/blktap/drivers/qcow-create.c b/tools/blktap/drivers/qcow-create.c
index 5ff50648a8..25abfcd1d4 100644
--- a/tools/blktap/drivers/qcow-create.c
+++ b/tools/blktap/drivers/qcow-create.c
@@ -52,7 +52,7 @@ static void help(void)
 {
 	fprintf(stderr, "Qcow-utils: v1.0.0\n");
 	fprintf(stderr, 
-		"usage: qcow-create [-h help] [-r reserve] <SIZE(MB)> <FILENAME> "
+		"usage: qcow-create [-h help] [-r reserve] [-f format] <SIZE(MB)> <FILENAME> "
 		"[<BACKING_FILENAME>]\n"); 
 	exit(-1);
 }
@@ -61,11 +61,13 @@ int main(int argc, char *argv[])
 {
 	int ret = -1, c, backed = 0;
 	int sparse =  1;
+	char *fmt = "qcow";
 	uint64_t size;
 	char filename[MAX_NAME_LEN], bfilename[MAX_NAME_LEN];
+	char *tmpfile;
 
         for(;;) {
-                c = getopt(argc, argv, "hr");
+                c = getopt(argc, argv, "hrf");
                 if (c == -1)
                         break;
                 switch(c) {
@@ -73,6 +75,9 @@ int main(int argc, char *argv[])
                         help();
                         exit(0);
                         break;
+                case 'f':
+                        fmt = argv[optind++];
+                        break;
                 case 'r':
 			sparse = 0;
 			break;
@@ -105,11 +110,16 @@ int main(int argc, char *argv[])
 		}
 	}
 
-	DFPRINTF("Creating file size %llu, name %s\n",(long long unsigned)size, filename);
-	if (!backed)
-		ret = qcow_create(filename,size,NULL,sparse);
-	else
-		ret = qcow_create(filename,size,bfilename,sparse);
+    tmpfile = backed ? bfilename: NULL; 
+    if (!strcmp(fmt, "qcow")) {
+        ret = qcow_create(filename, size, tmpfile, sparse);
+    } else if(!strcmp(fmt, "qcow2")) {
+        ret = qcow2_create(filename, size, tmpfile, sparse);
+    } else {
+        fprintf(stderr,"Unsupport format:%s\n", fmt);
+        exit(-1);
+    } 
+    DFPRINTF("Creating file size %llu, name %s\n",(long long unsigned)size, filename);
 
 	if (ret < 0)
 		DPRINTF("Unable to create QCOW file\n");
diff --git a/tools/blktap/drivers/tapdisk.h b/tools/blktap/drivers/tapdisk.h
index c8a21827ff..22450ff03b 100644
--- a/tools/blktap/drivers/tapdisk.h
+++ b/tools/blktap/drivers/tapdisk.h
@@ -266,4 +266,7 @@ typedef struct fd_list_entry {
 
 int qcow_create(const char *filename, uint64_t total_size,
 		const char *backing_file, int flags);
+
+int qcow2_create(const char *filename, uint64_t total_size,
+		const char *backing_file, int flags);
 #endif /*TAPDISK_H_*/