From: Chen Hanxiao <chenhanxiao@gmail.com>

This patch adds support for getting the usage of mounted
filesystem.
It's very useful when we try to monitor guest's filesystem.

Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
Cc: Eric Blake <eblake@redhat.com>
Signed-off-by: Chen Hanxiao <chenhanxiao@gmail.com>

---
v2:
   add description in qapi-schema and version numbers
v3:
   use float for usage to get more precision.
v4:
   make usage as a best-effort query and mark it as optional.

 qga/commands-posix.c | 17 +++++++++++++++++
 qga/qapi-schema.json |  3 ++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 0dc219dbcf..4facc76953 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -46,6 +46,7 @@ extern char **environ;
 #include <arpa/inet.h>
 #include <sys/socket.h>
 #include <net/if.h>
+#include <sys/statvfs.h>
 
 #ifdef FIFREEZE
 #define CONFIG_FSFREEZE
@@ -1072,6 +1073,9 @@ static GuestFilesystemInfo *build_guest_fsinfo(struct FsMount *mount,
                                                Error **errp)
 {
     GuestFilesystemInfo *fs = g_malloc0(sizeof(*fs));
+    struct statvfs buf;
+    unsigned long used, nonroot_total;
+    double usage;
     char *devpath = g_strdup_printf("/sys/dev/block/%u:%u",
                                     mount->devmajor, mount->devminor);
 
@@ -1079,7 +1083,20 @@ static GuestFilesystemInfo *build_guest_fsinfo(struct FsMount *mount,
     fs->type = g_strdup(mount->devtype);
     build_guest_fsinfo_for_device(devpath, fs, errp);
 
+    if (statvfs(fs->mountpoint, &buf)) {
+        fs->has_usage = false;
+        fs->usage = -1;
+    } else {
+        used = buf.f_blocks - buf.f_bfree;
+        nonroot_total = used + buf.f_bavail;
+        usage = (double) used / nonroot_total;
+
+        fs->has_usage = true;
+        fs->usage = usage;
+    }
+
     g_free(devpath);
+
     return fs;
 }
 
diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
index 17884c7c70..fcd427e86d 100644
--- a/qga/qapi-schema.json
+++ b/qga/qapi-schema.json
@@ -846,6 +846,7 @@
 # @name: disk name
 # @mountpoint: mount point path
 # @type: file system type string
+# @usage: file system usage, fraction between 0 and 1 (since 3.0)
 # @disk: an array of disk hardware information that the volume lies on,
 #        which may be empty if the disk type is not supported
 #
@@ -853,7 +854,7 @@
 ##
 { 'struct': 'GuestFilesystemInfo',
   'data': {'name': 'str', 'mountpoint': 'str', 'type': 'str',
-           'disk': ['GuestDiskAddress']} }
+           '*usage': 'number', 'disk': ['GuestDiskAddress']} }
 
 ##
 # @guest-get-fsinfo:
-- 
2.17.0

On Fri, Jun 01, 2018 at 02:11:21PM +0800, Chen Hanxiao wrote:
> From: Chen Hanxiao <chenhanxiao@gmail.com>
> 
> This patch adds support for getting the usage of mounted
> filesystem.
> It's very useful when we try to monitor guest's filesystem.
> 
> Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
> Cc: Eric Blake <eblake@redhat.com>
> Signed-off-by: Chen Hanxiao <chenhanxiao@gmail.com>
> 
> ---
> v2:
>    add description in qapi-schema and version numbers
> v3:
>    use float for usage to get more precision.
> v4:
>    make usage as a best-effort query and mark it as optional.
> 
>  qga/commands-posix.c | 17 +++++++++++++++++
>  qga/qapi-schema.json |  3 ++-
>  2 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> index 0dc219dbcf..4facc76953 100644
> --- a/qga/commands-posix.c
> +++ b/qga/commands-posix.c
> @@ -46,6 +46,7 @@ extern char **environ;
>  #include <arpa/inet.h>
>  #include <sys/socket.h>
>  #include <net/if.h>
> +#include <sys/statvfs.h>
>  
>  #ifdef FIFREEZE
>  #define CONFIG_FSFREEZE
> @@ -1072,6 +1073,9 @@ static GuestFilesystemInfo *build_guest_fsinfo(struct FsMount *mount,
>                                                 Error **errp)
>  {
>      GuestFilesystemInfo *fs = g_malloc0(sizeof(*fs));
> +    struct statvfs buf;
> +    unsigned long used, nonroot_total;
> +    double usage;
>      char *devpath = g_strdup_printf("/sys/dev/block/%u:%u",
>                                      mount->devmajor, mount->devminor);
>  
> @@ -1079,7 +1083,20 @@ static GuestFilesystemInfo *build_guest_fsinfo(struct FsMount *mount,
>      fs->type = g_strdup(mount->devtype);
>      build_guest_fsinfo_for_device(devpath, fs, errp);
>  
> +    if (statvfs(fs->mountpoint, &buf)) {
> +        fs->has_usage = false;
> +        fs->usage = -1;
> +    } else {
> +        used = buf.f_blocks - buf.f_bfree;
> +        nonroot_total = used + buf.f_bavail;
> +        usage = (double) used / nonroot_total;

Why calculate the usage here ?  IMHO it would make the command more useful
if we just reported two separate "used_bytes" and "total_bytes" values. The
app can convert to a percentage utilization value if they so desire, while
other apps can now get the raw values

Regards,
Daniel
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At 2018-06-01 20:19:56, "Daniel P. Berrangé" <berrange@redhat.com> wrote:
>On Fri, Jun 01, 2018 at 02:11:21PM +0800, Chen Hanxiao wrote:
>> From: Chen Hanxiao <chenhanxiao@gmail.com>
>> 
>> This patch adds support for getting the usage of mounted
>> filesystem.
>> It's very useful when we try to monitor guest's filesystem.
>> 
>> Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
>> Cc: Eric Blake <eblake@redhat.com>
>> Signed-off-by: Chen Hanxiao <chenhanxiao@gmail.com>
>> 
>> ---
>> v2:
>>    add description in qapi-schema and version numbers
>> v3:
>>    use float for usage to get more precision.
>> v4:
>>    make usage as a best-effort query and mark it as optional.
>> 
>>  qga/commands-posix.c | 17 +++++++++++++++++
>>  qga/qapi-schema.json |  3 ++-
>>  2 files changed, 19 insertions(+), 1 deletion(-)
>> 
>> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
>> index 0dc219dbcf..4facc76953 100644
>> --- a/qga/commands-posix.c
>> +++ b/qga/commands-posix.c
>> @@ -46,6 +46,7 @@ extern char **environ;
>>  #include <arpa/inet.h>
>>  #include <sys/socket.h>
>>  #include <net/if.h>
>> +#include <sys/statvfs.h>
>>  
>>  #ifdef FIFREEZE
>>  #define CONFIG_FSFREEZE
>> @@ -1072,6 +1073,9 @@ static GuestFilesystemInfo *build_guest_fsinfo(struct FsMount *mount,
>>                                                 Error **errp)
>>  {
>>      GuestFilesystemInfo *fs = g_malloc0(sizeof(*fs));
>> +    struct statvfs buf;
>> +    unsigned long used, nonroot_total;
>> +    double usage;
>>      char *devpath = g_strdup_printf("/sys/dev/block/%u:%u",
>>                                      mount->devmajor, mount->devminor);
>>  
>> @@ -1079,7 +1083,20 @@ static GuestFilesystemInfo *build_guest_fsinfo(struct FsMount *mount,
>>      fs->type = g_strdup(mount->devtype);
>>      build_guest_fsinfo_for_device(devpath, fs, errp);
>>  
>> +    if (statvfs(fs->mountpoint, &buf)) {
>> +        fs->has_usage = false;
>> +        fs->usage = -1;
>> +    } else {
>> +        used = buf.f_blocks - buf.f_bfree;
>> +        nonroot_total = used + buf.f_bavail;
>> +        usage = (double) used / nonroot_total;
>
>Why calculate the usage here ?  IMHO it would make the command more useful
>if we just reported two separate "used_bytes" and "total_bytes" values. The
>app can convert to a percentage utilization value if they so desire, while
>other apps can now get the raw values

Thanks for your advice.
Will be fixed in v5.
Also adding support for qga-win.

Regards,
- Chen