qemu-img create: cache paramter only use for reg file image

The paramter 'cache' is invalid for host device(/dev/xxx). If
'qemu-img create' operator performed on host device, the host
device not support 'cache' would result 'qemu-img create excute'
failed.

Signed-off-by: Jinhua Cao <caojinhua1@huawei.com>

qemu-img-create-cache-paramter-only-use-for-reg-file.patch

@@ -0,0 +1,66 @@
+From 85a876e0d28eac4c71350baede38ca755fdf6df0 Mon Sep 17 00:00:00 2001
+From: Jinhua Cao <caojinhua1@huawei.com>
+Date: Thu, 24 Mar 2022 17:12:49 +0800
+Subject: [PATCH] qemu-img create: 'cache' paramter only use for reg file image
+
+The paramter 'cache' is invalid for host device(/dev/xxx). If
+'qemu-img create' operator performed on host device, the host
+device not support 'cache' would result 'qemu-img create' execute
+failed.
+
+Signed-off-by: Jinhua Cao <caojinhua1@huawei.com>
+---
+ qemu-img.c | 30 ++++++++++++++++++++++++------
+ 1 file changed, 24 insertions(+), 6 deletions(-)
+
+diff --git a/qemu-img.c b/qemu-img.c
+index 9409558772..059bf42fc1 100644
+--- a/qemu-img.c
++++ b/qemu-img.c
+@@ -496,6 +496,22 @@ static int64_t cvtnum(const char *name, const char *value)
+     return cvtnum_full(name, value, 0, INT64_MAX);
+ }
+ 
++static bool is_reg_file(const char *filename)
++{
++    struct stat st;
++
++    /* file not exist, file will be create later, so it's a reg file */
++    if (access(filename, F_OK) == -1) {
++        return true;
++    }
++
++    /* file exist, check file type */
++    if (stat(filename, &st) >= 0 && S_ISREG(st.st_mode)) {
++        return true;
++    }
++    return false;
++}
++
+ static int img_create(int argc, char **argv)
+ {
+     int c;
+@@ -586,12 +602,14 @@ static int img_create(int argc, char **argv)
+         error_exit("Unexpected argument: %s", argv[optind]);
+     }
+ 
+-    if (!options) {
+-        options = g_strdup_printf(BLOCK_OPT_CACHE"=%s", cache);
+-    } else {
+-        char *old_options = options;
+-        options = g_strdup_printf("%s,"BLOCK_OPT_CACHE"=%s", options, cache);
+-        g_free(old_options);
++    if (is_reg_file(filename)) {
++        if (!options) {
++            options = g_strdup_printf(BLOCK_OPT_CACHE"=%s", cache);
++        } else {
++            char *old_options = options;
++            options = g_strdup_printf("%s,"BLOCK_OPT_CACHE"=%s", options, cache);
++            g_free(old_options);
++        }
+     }
+ 
+     bdrv_img_create(filename, fmt, base_filename, base_fmt,
+-- 
+2.27.0
+

qemu.spec

@@ -1,6 +1,6 @@
 Name: qemu
 Version: 6.2.0
-Release: 28
+Release: 29
 Epoch: 2
 Summary: QEMU is a generic and open source machine emulator and virtualizer
 License: GPLv2 and BSD and MIT and CC-BY-SA-4.0
@@ -236,6 +236,7 @@ Patch0222: scsi-bus-fix-unmatched-object_unref.patch
 Patch0223: tools-virtiofsd-Add-rseq-syscall-to-the-seccomp-allo.patch
 Patch0224: sw_64-Add-sw64-architecture-support.patch
 Patch0225: coro-support-live-patch-for-libcare.patch
+Patch0226: qemu-img-create-cache-paramter-only-use-for-reg-file.patch
 
 BuildRequires: flex
 BuildRequires: gcc
@@ -696,6 +697,9 @@ getent passwd qemu >/dev/null || \
 %endif
 
 %changelog
+* Fri Mar 25 2022 Jinhua Cao <caojinhua1@huawei.com>
+- qemu-img create: 'cache' paramter only use for reg file image
+
 * Thu Mar 24 2022 Yan Wang <wangyan122@huawei.com>
 - spec: add hw-usb-host rpm package