From: Patrik Martinsson <martinsson.patrik@xxxxxxxxx>
This commit simply adds the '--force' flag to the blockresize
command to prevent accidental shrinking of a block device. Similar
behaviour is already present on the vol-resize command and it
makes sense to mimic it.
Implemented in virsh and not in the API. This is to prevent existing
applications using the BlockResize-API from 'breaking'.
Signed-off-by: Patrik Martinsson <martinsson.patrik@xxxxxxxxx>
---
docs/news.xml | 13 +++++++++++++
tools/virsh-domain.c | 34 +++++++++++++++++++++++++++++++---
tools/virsh.pod | 6 +++++-
3 files changed, 49 insertions(+), 4 deletions(-)
diff --git a/docs/news.xml b/docs/news.xml
index c8d55e357b..595d63137a 100644
--- a/docs/news.xml
+++ b/docs/news.xml
@@ -61,6 +61,19 @@
</change>
</section>
<section title="Improvements">
+ <change>
+ <summary>
+ virsh: Add --force to the blockresize command
+ </summary>
+ <description>
+ To prevent accidental shrinking of a block device the --force flag
+ is introduced for the blockresize command, similar to the --shrink
+ flag for the vol-resize command. If you intend to shrink a block
+ device with <code> virsh blockresize</code>, you must now include
+ --force, otherwise the command will fail with an error. This change
+ is only in virsh, not in the API.
+ </description>
+ </change>
</section>
<section title="Bug fixes">
<change>
diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index 2f3ac2d430..412b7e4028 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -2920,6 +2920,10 @@ static const vshCmdOptDef opts_blockresize[] = {
.flags = VSH_OFLAG_REQ,
.help = N_("New size of the block device, as scaled integer (default KiB)")
},
+ {.name = "force",
+ .type = VSH_OT_BOOL,
+ .help = N_("Allow the resize to shrink the blockdevice")
+ },
{.name = NULL}
};
@@ -2927,10 +2931,12 @@ static bool
cmdBlockresize(vshControl *ctl, const vshCmd *cmd)
{
virDomainPtr dom;
+ virDomainBlockInfo info;
const char *path = NULL;
unsigned long long size = 0;
unsigned int flags = 0;
bool ret = false;
+ bool force = vshCommandOptBool(cmd, "force");
if (vshCommandOptStringReq(ctl, cmd, "path", (const char **) &path) < 0)
return false;
@@ -2938,24 +2944,46 @@ cmdBlockresize(vshControl *ctl, const vshCmd *cmd)
if (vshCommandOptScaledInt(ctl, cmd, "size", &size, 1024, ULLONG_MAX) < 0)
return false;
+ if (!(dom = virshCommandOptDomain(ctl, cmd, NULL)))
+ return false;
+
+ if (virDomainGetBlockInfo(dom, path, &info, 0) < 0)
+ goto cleanup;
+
+ /* Make sure to not shrink device if it's already given size */
+ if (size == info.capacity) {
+ vshPrintExtra(ctl, _("Given size (%llu bytes) is the same as the "
+ "current capacity of '%s', not doing anything"),
+ size, path);
+ goto cleanup;
+ }
+
+ /* Make sure to only allow shrink of device if --force is specified */
+ if (size < info.capacity && !force) {
+ vshError(ctl, _("Can't shrink the size of '%s' below current capacity, "
+ "unless --force is explicity specified"), path);
+ goto cleanup;
+ }
+
/* Prefer the older interface of KiB. */
if (size % 1024 == 0)
size /= 1024;
else
flags |= VIR_DOMAIN_BLOCK_RESIZE_BYTES;
- if (!(dom = virshCommandOptDomain(ctl, cmd, NULL)))
- return false;
-
if (virDomainBlockResize(dom, path, size, flags) < 0) {
vshError(ctl, _("Failed to resize block device '%s'"), path);
+ goto cleanup;
} else {
vshPrintExtra(ctl, _("Block device '%s' is resized"), path);
ret = true;
+ goto cleanup;
}
+ cleanup:
virshDomainFree(dom);
return ret;
+
}
#ifndef WIN32
diff --git a/tools/virsh.pod b/tools/virsh.pod
index cf2798e71a..dc34a2a263 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -1027,7 +1027,7 @@ I<bandwidth> specifies copying bandwidth limit in MiB/s. For further information
on the I<bandwidth> argument see the corresponding section for the B<blockjob>
command.
-=item B<blockresize> I<domain> I<path> I<size>
+=item B<blockresize> I<domain> I<path> I<size> [I<--force>]
Resize a block device of domain while the domain is running, I<path>
specifies the absolute path of the block device; it corresponds
@@ -1040,6 +1040,10 @@ I<size> is a scaled integer (see B<NOTES> above) which defaults to KiB
"B" to get bytes (note that for historical reasons, this differs from
B<vol-resize> which defaults to bytes without a suffix).
+The I<--force> flag is needed when specified I<size> is less than the current
+capacity of the device, ie. when shrinking a device. Always exercise caution
+when shrinking a block device.
+
=item B<console> I<domain> [I<devname>] [I<--safe>] [I<--force>]
Connect the virtual serial console for the guest. The optional
--
2.23.0
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