blkdebug: Simplify override logic

Rather than store into a local variable, then copy to the struct
if the value is valid, then reporting errors otherwise, it is
simpler to just store into the struct and report errors if the
value is invalid.  This however requires that the struct store
a 64-bit number, rather than a narrower type.  Likewise, setting
a sane errno value in ret prior to the sequence of parsing and
jumping to out: on error makes it easier for the next patch to
add a chain of similar checks.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-id: 20170429191419.30051-8-eblake@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
(cherry picked from commit 3dc834f8795a46f919d90b1e5369308628858601)
* prereq for 81c219a
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/block/blkdebug.c b/block/blkdebug.c
index a3dc5f6677d3008a04476e75dbdde69eec5cc9d7..2b934ef0fd7aad3f80f6339cef1831baf7bd4648 100644 (file)
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -38,7 +38,7 @@
 typedef struct BDRVBlkdebugState {
     int state;
     int new_state;
-    int align;
+    uint64_t align;
 
     /* For blkdebug_refresh_filename() */
     char *config_file;
@@ -353,7 +353,6 @@ static int blkdebug_open(BlockDriverState *bs, QDict *options, int flags,
     BDRVBlkdebugState *s = bs->opaque;
     QemuOpts *opts;
     Error *local_err = NULL;
-    uint64_t align;
     int ret;
 
     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
@@ -387,20 +386,17 @@ static int blkdebug_open(BlockDriverState *bs, QDict *options, int flags,
         bs->file->bs->supported_write_flags;
     bs->supported_zero_flags = (BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP) &
         bs->file->bs->supported_zero_flags;
+    ret = -EINVAL;
 
     /* Set request alignment */
-    align = qemu_opt_get_size(opts, "align", 0);
-    if (align < INT_MAX && is_power_of_2(align)) {
-        s->align = align;
-    } else if (align) {
-        error_setg(errp, "Invalid alignment");
-        ret = -EINVAL;
+    s->align = qemu_opt_get_size(opts, "align", 0);
+    if (s->align && (s->align >= INT_MAX || !is_power_of_2(s->align))) {
+        error_setg(errp, "Cannot meet constraints with align %" PRIu64,
+                   s->align);
         goto out;
     }
 
     ret = 0;
-    goto out;
-
 out:
     if (ret < 0) {
         g_free(s->config_file);