Add missing long options and --help output.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
 qemu-img.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c
index d4dafebff9..a1a0ba99f0 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -65,7 +65,6 @@ typedef struct img_cmd_t {
 
 enum {
     OPTION_OUTPUT = 256,
-    OPTION_BACKING_CHAIN = 257,
     OPTION_OBJECT = 258,
     OPTION_IMAGE_OPTS = 259,
     OPTION_PATTERN = 260,
@@ -3173,13 +3172,13 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
             {"help", no_argument, 0, 'h'},
             {"format", required_argument, 0, 'f'},
             {"output", required_argument, 0, OPTION_OUTPUT},
-            {"backing-chain", no_argument, 0, OPTION_BACKING_CHAIN},
+            {"backing-chain", no_argument, 0, 'b'},
             {"object", required_argument, 0, OPTION_OBJECT},
             {"image-opts", no_argument, 0, OPTION_IMAGE_OPTS},
             {"force-share", no_argument, 0, 'U'},
             {0, 0, 0, 0}
         };
-        c = getopt_long(argc, argv, ":f:hU",
+        c = getopt_long(argc, argv, ":f:hbU",
                         long_options, &option_index);
         if (c == -1) {
             break;
@@ -3192,7 +3191,20 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
             unrecognized_option(ccmd, argv[optind - 1]);
             break;
         case 'h':
-            help();
+            cmd_help(ccmd,
+"[-f FMT | --image-opts] [-b] [-U] [--object OBJDEF]\n"
+"	[--output human|json] FILENAME\n"
+,
+" -f|--format FMT - specify FILENAME image format explicitly\n"
+" --image-opts - indicates that FILENAME is a complete image specification\n"
+"  instead of a file name (incompatible with --format)\n"
+" -b|--backing-chain - display information about backing chaing\n"
+" (in case the image is stacked\n"
+" -U|--force-share - open image in shared mode for concurrent access\n"
+" --object OBJDEF - QEMU user-creatable object (eg encryption key)\n"
+" --output human|json - specify output format name (default human)\n"
+" FILENAME - image file name (or specification with --image-opts)\n"
+);
             break;
         case 'f':
             fmt = optarg;
@@ -3203,7 +3215,7 @@ static int img_info(const img_cmd_t *ccmd, int argc, char **argv)
         case OPTION_OUTPUT:
             output_format = parse_output_format(ccmd, optarg);
             break;
-        case OPTION_BACKING_CHAIN:
+        case 'b':
             chain = true;
             break;
         case OPTION_OBJECT:
-- 
2.39.2