On 10/16/20 10:23 AM, Eric Blake wrote:
A rather trivial decoding; we may enhance it further if qemu extends
things to give an integer depth alongside its tri-state encoding.
---
I'll wait to push this to libnbd until the counterpart qemu patches
land upstream, although it looks like I've got positive review.
Whoops, I accidentally pushed this before qemu stuff landed upstream,
and in the meantime, we changed our minds on what to expose over
qemu:allocation-depth to be a bare integer rather than a tri-state.
I'll push this followup (but this time, wait for the actual qemu patch
to land). In fact, I should probably add test-suite coverage...
From eba8734654e6fd340e18b3e07c3213ed1a0ab9e8 Mon Sep 17 00:00:00 2001
From: Eric Blake <eblake(a)redhat.com>
Date: Tue, 27 Oct 2020 10:27:25 -0500
Subject: [libnbd PATCH] info: Adjust to actual 'qemu-nbd -A' semantics
Review on the qemu list has led to an altered definition of what
'qemu:allocation-depth' should report: rather than a tri-state value,
it is an actual depth. It's time to match what actually got committed
into qemu, which in turn means a slight refactoring to use a malloc'd
string for a description.
Fixes: 71455c021
---
info/nbdinfo.c | 27 +++++++++++++++------------
1 file changed, 15 insertions(+), 12 deletions(-)
diff --git a/info/nbdinfo.c b/info/nbdinfo.c
index 2b22f51..b152f28 100644
--- a/info/nbdinfo.c
+++ b/info/nbdinfo.c
@@ -767,28 +767,30 @@ get_content (struct nbd_handle *nbd, int64_t size)
}
/* Callback handling --map. */
-static const char *
+static char *
extent_description (const char *metacontext, uint32_t type)
{
+ char *ret;
+
if (strcmp (metacontext, "base:allocation") == 0) {
switch (type) {
- case 0: return "allocated";
- case 1: return "hole";
- case 2: return "zero";
- case 3: return "hole,zero";
+ case 0: return strdup ("allocated");
+ case 1: return strdup ("hole");
+ case 2: return strdup ("zero");
+ case 3: return strdup ("hole,zero");
}
}
else if (strncmp (metacontext, "qemu:dirty-bitmap:", 18) == 0) {
switch (type) {
- case 0: return "clean";
- case 1: return "dirty";
+ case 0: return strdup ("clean");
+ case 1: return strdup ("dirty");
}
}
else if (strcmp (metacontext, "qemu:allocation-depth") == 0) {
- switch (type & 3) {
- case 0: return "unallocated";
- case 1: return "local";
- case 2: return "backing";
+ switch (type) {
+ case 0: return strdup ("unallocated");
+ case 1: return strdup ("local");
+ case 2: asprintf (&ret, "backing depth %d", type); return ret;
}
}
@@ -810,7 +812,7 @@ extent_callback (void *user_data, const char
*metacontext,
/* Print the entries received. */
for (i = 0; i < nr_entries; i += 2) {
- const char *descr = extent_description (map, entries[i+1]);
+ char *descr = extent_description (map, entries[i+1]);
if (!json_output) {
fprintf (fp, "%10" PRIu64 " "
@@ -837,6 +839,7 @@ extent_callback (void *user_data, const char
*metacontext,
comma = true;
}
+ free (descr);
offset += entries[i];
}
--
2.29.0
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization:
qemu.org |
libvirt.org