[Qemu-block] [PATCH v3 25/44] qemu-io: Add 'open -u' to set BDRV_O_UNMAP after the fact

[Eric Blake]

When opening a file from the command line, qemu-io defaults
to BDRV_O_UNMAP but allows -d to give full control to disable
unmaps. But when opening via the 'open' command, qemu-io did
not set BDRV_O_UNMAP, and had no way to allow it.

Make it at least possible to symmetrically test things:
'qemu-io -d ignore' at the CLI now matches 'qemu-io> open'
in batch mode, and 'qemu-io' or 'qemu-io -d unmap' at
the CLI matches 'qemu-io> open -u'.

Signed-off-by: Eric Blake <address@hidden>
---
 qemu-io.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/qemu-io.c b/qemu-io.c
index cdc9497..dc8d124 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -107,6 +107,7 @@ static void open_help(void)
 " -r, -- open file read-only\n"
 " -s, -- use snapshot file\n"
 " -n, -- disable host cache\n"
+" -u, -- allow discard and zero operations to unmap\n"
 " -o, -- options to be given to the block driver"
 "\n");
 }
@@ -120,7 +121,7 @@ static const cmdinfo_t open_cmd = {
     .argmin     = 1,
     .argmax     = -1,
     .flags      = CMD_NOFILE_OK,
-    .args       = "[-Crsn] [-o options] [path]",
+    .args       = "[-Crsnu] [-o options] [path]",
     .oneline    = "open the file specified by path",
     .help       = open_help,
 };
@@ -144,7 +145,7 @@ static int open_f(BlockBackend *blk, int argc, char **argv)
     QemuOpts *qopts;
     QDict *opts;

-    while ((c = getopt(argc, argv, "snrgo:")) != -1) {
+    while ((c = getopt(argc, argv, "snrguo:")) != -1) {
         switch (c) {
         case 's':
             flags |= BDRV_O_SNAPSHOT;
@@ -156,6 +157,9 @@ static int open_f(BlockBackend *blk, int argc, char **argv)
         case 'r':
             readonly = 1;
             break;
+        case 'u':
+            flags |= BDRV_O_UNMAP;
+            break;
         case 'o':
             if (imageOpts) {
                 printf("--image-opts and 'open -o' are mutually exclusive\n");
-- 
2.5.5