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Re: [Qemu-devel] [PATCH v4] qga: add mountpoint usage to GuestFilesystem
From: |
Daniel P . Berrangé |
Subject: |
Re: [Qemu-devel] [PATCH v4] qga: add mountpoint usage to GuestFilesystemInfo |
Date: |
Fri, 1 Jun 2018 13:19:56 +0100 |
User-agent: |
Mutt/1.9.5 (2018-04-13) |
On Fri, Jun 01, 2018 at 02:11:21PM +0800, Chen Hanxiao wrote:
> From: Chen Hanxiao <address@hidden>
>
> 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 <address@hidden>
> Cc: Eric Blake <address@hidden>
> Signed-off-by: Chen Hanxiao <address@hidden>
>
> ---
> 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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