[PATCH RESEND] qga: add guest-get-diskstats command for Linux guests

[luzhipeng <luzhipeng@cestc.cn>]

Add a new 'guest-get-diskstats' command for report disk io statistics
for Linux guests. This can be usefull for getting io flow or handling
IO fault, no need to enter guests.

Signed-off-by: luzhipeng <luzhipeng@cestc.cn>
---
 qga/commands-posix.c | 94 ++++++++++++++++++++++++++++++++++++++++++++
 qga/commands-win32.c |  6 +++
 qga/qapi-schema.json | 86 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 186 insertions(+)

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 69f209af87..2b96c9ae6e 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -2783,6 +2783,93 @@ GuestMemoryBlockInfo *qmp_guest_get_memory_block_info(Error **errp)
     return info;
 }
 
+#define MAX_NAME_LEN 128
+static GuestDiskStatsInfoList *guest_get_diskstats(Error **errp)
+{
+#ifdef CONFIG_LINUX
+    GuestDiskStatsInfoList *head = NULL, **tail = &head;
+    const char *diskstats = "/proc/diskstats";
+    FILE *fp;
+    size_t n;
+    char *line = NULL;
+    char dev_name[MAX_NAME_LEN];
+    int i;
+    unsigned int ios_pgr, tot_ticks, rq_ticks, wr_ticks, dc_ticks, fl_ticks;
+    unsigned long rd_ios, rd_merges_or_rd_sec, rd_ticks_or_wr_sec, wr_ios;
+    unsigned long wr_merges, rd_sec_or_wr_ios, wr_sec;
+    unsigned long dc_ios, dc_merges, dc_sec, fl_ios;
+    unsigned int major, minor;
+
+    fp = fopen(diskstats, "r");
+    if (fp  == NULL) {
+        error_setg_errno(errp, errno, "open(\"%s\")", diskstats);
+        return NULL;
+    }
+    while (getline(&line, &n, fp) != -1) {
+        i = sscanf(line, "%u %u %s %lu %lu %lu"
+                   "%lu %lu %lu %lu %u %u %u %u"
+                   "%lu %lu %lu %u %lu %u",
+                  &major, &minor, dev_name,
+                  &rd_ios, &rd_merges_or_rd_sec, &rd_sec_or_wr_ios,
+                  &rd_ticks_or_wr_sec, &wr_ios, &wr_merges, &wr_sec,
+                  &wr_ticks, &ios_pgr, &tot_ticks, &rq_ticks,
+                  &dc_ios, &dc_merges, &dc_sec, &dc_ticks,
+                  &fl_ios, &fl_ticks);
+        GuestDiskStatsInfo *diskstatinfo = g_malloc0(sizeof *diskstatinfo);
+        GuestDiskStats *diskstat = g_malloc0(sizeof *diskstat);
+        if (i >= 14) {
+            diskstatinfo->name = g_strdup(dev_name);
+            diskstatinfo->major = major;
+            diskstatinfo->minor = minor;
+            diskstat->rd_ios = rd_ios;
+            diskstat->rd_merges = rd_merges_or_rd_sec;
+            diskstat->rd_sectors = rd_sec_or_wr_ios;
+            diskstat->rd_ticks = rd_ticks_or_wr_sec;
+            diskstat->wr_ios = wr_ios;
+            diskstat->wr_merges = wr_merges;
+            diskstat->wr_sectors = wr_sec;
+            diskstat->wr_ticks = wr_ticks;
+            diskstat->ios_pgr = ios_pgr;
+            diskstat->tot_ticks = tot_ticks;
+            diskstat->rq_ticks = rq_ticks;
+            if (i >= 18) {
+                diskstat->dc_ios = dc_ios;
+                diskstat->dc_merges = dc_merges;
+                diskstat->dc_sectors = dc_sec;
+                diskstat->dc_ticks = dc_ticks;
+            }
+            if (i >= 20) {
+                diskstat->fl_ios = fl_ios;
+                diskstat->fl_ticks = fl_ticks;
+            }
+            diskstatinfo->stats = diskstat;
+            QAPI_LIST_APPEND(tail, diskstatinfo);
+        } else if (i == 7) {
+            diskstatinfo->name = g_strdup(dev_name);
+            diskstatinfo->major = major;
+            diskstatinfo->minor = minor;
+            diskstat->rd_ios = rd_ios;
+            diskstat->rd_sectors = rd_merges_or_rd_sec;
+            diskstat->wr_ios = rd_sec_or_wr_ios;
+            diskstat->wr_sectors = rd_ticks_or_wr_sec;
+        } else {
+            g_free(diskstat);
+            g_free(diskstatinfo);
+        }
+    }
+    fclose(fp);
+    return head;
+#else
+    g_debug("disk stats reporting available only for Linux");
+    return NULL;
+#endif
+}
+
+GuestDiskStatsInfoList *qmp_guest_get_diskstats(Error **errp)
+{
+    return guest_get_diskstats(errp);
+}
+
 #else /* defined(__linux__) */
 
 void qmp_guest_suspend_disk(Error **errp)
@@ -3131,6 +3218,13 @@ GuestDiskInfoList *qmp_guest_get_disks(Error **errp)
     return NULL;
 }
 
+GuestDiskStatsInfoList *qmp_guest_get_diskstats(Error **errp)
+{
+    error_setg(errp, QERR_UNSUPPORTED);
+    return NULL;
+}
+
+
 #endif /* CONFIG_FSFREEZE */
 
 #if !defined(CONFIG_FSTRIM)
diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index d56b5fd2a7..dcdeb76a68 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -2532,3 +2532,9 @@ char *qga_get_host_name(Error **errp)
 
     return g_utf16_to_utf8(tmp, size, NULL, NULL, NULL);
 }
+
+GuestDiskStatsInfoList *qmp_guest_get_diskstats(Error **errp)
+{
+    error_setg(errp, QERR_UNSUPPORTED);
+    return NULL;
+}
diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
index 4d8e506c9e..ec48629476 100644
--- a/qga/qapi-schema.json
+++ b/qga/qapi-schema.json
@@ -1490,3 +1490,89 @@
 { 'command': 'guest-ssh-remove-authorized-keys',
   'data': { 'username': 'str', 'keys': ['str'] },
   'if': 'CONFIG_POSIX' }
+
+##
+# @GuestDiskStats:
+#
+# @rd-sectors: of sectors read
+#
+# @wr-sectors: of sectors write
+#
+# @dc-sectors: of sectors discard
+#
+# @rd-ios: of read operations issued to the device
+#
+# @rd-merges: of read requests merged
+#
+# @wr-ios: of write operations issued to the device
+#
+# @wr-merges: of write requests merged
+#
+# @dc-ios: of discard operations issued to the device
+#
+# @dc-merges: of discard requests merged
+#
+# @fl-ios: of flush requests issued to the device
+#
+# @rd-ticks: Time of read requests in queue
+#
+# @wr-ticks: Time of write requests in queue
+#
+# @dc-ticks: Time of discard requests in queue
+#
+# @fl-ticks: Time of flush requests in queue
+#
+# @ios-pgr: of I/Os in progress
+#
+# @tot-ticks: of ticks total (for this device) for I/O
+#
+# @rq-ticks: of ticks requests spent in queue
+#
+# Since: 7.1
+##
+{ 'struct': 'GuestDiskStats',
+  'data': {'rd-sectors': 'uint64',
+            'wr-sectors': 'uint64',
+            'dc-sectors': 'uint64',
+            'rd-ios': 'uint64',
+            'rd-merges': 'uint64',
+            'wr-ios': 'uint64',
+            'wr-merges': 'uint64',
+            'dc-ios': 'uint64',
+            'dc-merges': 'uint64',
+            'fl-ios': 'uint64',
+            'rd-ticks': 'uint64',
+            'wr-ticks': 'uint64',
+            'dc-ticks': 'uint64',
+            'fl-ticks': 'uint64',
+            'ios-pgr': 'uint64',
+            'tot-ticks': 'uint64',
+            'rq-ticks': 'uint64'
+           } }
+
+##
+# @GuestDiskStatsInfo:
+#
+# @name disk name
+#
+# @major major of disk
+#
+# @minor minor of disk
+##
+{ 'struct': 'GuestDiskStatsInfo',
+  'data': {'name': 'str',
+           'major': 'uint64',
+           'minor': 'uint64',
+           'stats': 'GuestDiskStats' } }
+
+##
+# @guest-get-diskstats:
+#
+# Retrieve information about disk io.
+# Returns: List of disk stats of guest.
+#
+# Since: 7.1
+##
+{ 'command': 'guest-get-diskstats',
+  'returns': ['GuestDiskStatsInfo']
+}
-- 
2.31.1