[Qemu-devel] [PATCH] LUKS: support preallocation in qemu-img

[Maxim Levitsky]

preallocation=off and preallocation=metadata
both allocate luks header only, and preallocation=falloc/full
is passed to underlying file, with the given image size.

Note that the actual preallocated size is a bit smaller due
to luks header.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1534951

Signed-off-by: Maxim Levitsky <address@hidden>
---
 block/crypto.c | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/block/crypto.c b/block/crypto.c
index 8237424ae6..74b789d278 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -251,6 +251,7 @@ static int block_crypto_open_generic(QCryptoBlockFormat 
format,
 static int block_crypto_co_create_generic(BlockDriverState *bs,
                                           int64_t size,
                                           QCryptoBlockCreateOptions *opts,
+                                          PreallocMode prealloc,
                                           Error **errp)
 {
     int ret;
@@ -266,6 +267,13 @@ static int block_crypto_co_create_generic(BlockDriverState 
*bs,
         goto cleanup;
     }
 
+    if (prealloc != PREALLOC_MODE_OFF) {
+        ret = blk_truncate(blk, size, prealloc, errp);
+        if (ret < 0) {
+                goto cleanup;
+        }
+    }
+
     data = (struct BlockCryptoCreateData) {
         .blk = blk,
         .size = size,
@@ -516,7 +524,7 @@ block_crypto_co_create_luks(BlockdevCreateOptions 
*create_options, Error **errp)
     };
 
     ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts,
-                                         errp);
+                                         PREALLOC_MODE_OFF, errp);
     if (ret < 0) {
         goto fail;
     }
@@ -534,12 +542,28 @@ static int coroutine_fn 
block_crypto_co_create_opts_luks(const char *filename,
     QCryptoBlockCreateOptions *create_opts = NULL;
     BlockDriverState *bs = NULL;
     QDict *cryptoopts;
+    PreallocMode prealloc;
+    char *buf = NULL;
     int64_t size;
     int ret;
+    Error *local_err = NULL;
 
     /* Parse options */
     size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
 
+    buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
+    prealloc = qapi_enum_parse(&PreallocMode_lookup, buf,
+                                   PREALLOC_MODE_OFF, &local_err);
+    g_free(buf);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return -EINVAL;
+    }
+
+    if (prealloc == PREALLOC_MODE_METADATA) {
+        prealloc  = PREALLOC_MODE_OFF;
+    }
+
     cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL,
                                              &block_crypto_create_opts_luks,
                                              true);
@@ -565,7 +589,7 @@ static int coroutine_fn 
block_crypto_co_create_opts_luks(const char *filename,
     }
 
     /* Create format layer */
-    ret = block_crypto_co_create_generic(bs, size, create_opts, errp);
+    ret = block_crypto_co_create_generic(bs, size, create_opts, prealloc, 
errp);
     if (ret < 0) {
         goto fail;
     }
-- 
2.17.2