[PATCH v2] tools/xentop: Add VBD3 support to xentop

[Fouad Hilly <fouad.hilly@xxxxxxxxx>]

From: Pritha Srivastava <pritha.srivastava@xxxxxxxxxx>

xl now knows how to drive tapdisk, so modify libxenstat to
understand vbd3 statistics.

Signed-off-by: Pritha Srivastava <pritha.srivastava@xxxxxxxxxx>
Signed-off-by: Jorge Martin <jorge.martin@xxxxxxxxxx>
Signed-off-by: Fouad Hilly <fouad.hilly@xxxxxxxxx>
---
CC: Wei Liu <wl@xxxxxxx>
CC: Anthony PERARD <anthony.perard@xxxxxxxxxx>
CC: Juergen Gross <jgross@xxxxxxxx>

v2:
- Fix order of SoB
- Fix Syntax
- Re-order free(path)
---
 tools/libs/stat/xenstat_linux.c | 65 ++++++++++++++++++++++++++++++++-
 tools/libs/stat/xenstat_priv.h  | 16 ++++++++
 tools/xentop/xentop.c           |  1 +
 3 files changed, 81 insertions(+), 1 deletion(-)

diff --git a/tools/libs/stat/xenstat_linux.c b/tools/libs/stat/xenstat_linux.c
index cbba54aa83ee..6d82e204aad4 100644
--- a/tools/libs/stat/xenstat_linux.c
+++ b/tools/libs/stat/xenstat_linux.c
@@ -390,6 +390,38 @@ void xenstat_uninit_networks(xenstat_handle * handle)
                fclose(priv->procnetdev);
 }
 
+static int read_attributes_vbd3(char *vbd3_path, xenstat_vbd *vbd)
+{
+       FILE *fp;
+       struct vbd3_stats vbd3_stats;
+
+       fp = fopen(vbd3_path, "rb");
+
+       if (fp == NULL) {
+               return -1;
+       }
+
+       if (fread(&vbd3_stats, sizeof(struct vbd3_stats), 1, fp) != 1) {
+               fclose(fp);
+               return -1;
+       }
+
+       if (vbd3_stats.version != 1) {
+               fclose(fp);
+               return -1;
+       }
+
+       vbd->oo_reqs = vbd3_stats.oo_reqs;
+       vbd->rd_reqs = vbd3_stats.read_reqs_submitted;
+       vbd->rd_sects = vbd3_stats.read_sectors;
+       vbd->wr_reqs = vbd3_stats.write_reqs_submitted;
+       vbd->wr_sects = vbd3_stats.write_sectors;
+
+       fclose(fp);
+
+       return 0;
+}
+
 static int read_attributes_vbd(const char *vbd_directory, const char *what, 
char *ret, int cap)
 {
        static char file_name[80];
@@ -438,7 +470,7 @@ int xenstat_collect_vbds(xenstat_node * node)
                int ret;
                char buf[256];
 
-               ret = sscanf(dp->d_name, "%3s-%u-%u", buf, &domid, &vbd.dev);
+               ret = sscanf(dp->d_name, "%255[^-]-%u-%u", buf, &domid, 
&vbd.dev);
                if (ret != 3)
                        continue;
                if (!(strstr(buf, "vbd")) && !(strstr(buf, "tap")))
@@ -448,6 +480,8 @@ int xenstat_collect_vbds(xenstat_node * node)
                        vbd.back_type = 1;
                else if (strcmp(buf,"tap") == 0)
                        vbd.back_type = 2;
+               else if (strcmp(buf,"vbd3") == 0)
+                       vbd.back_type = 3;
                else
                        vbd.back_type = 0;
 
@@ -479,6 +513,35 @@ int xenstat_collect_vbds(xenstat_node * node)
                                vbd.error = 1;
                        }
                }
+               else if (vbd.back_type == 3)
+               {
+                       char *td3_pid;
+                       char *path;
+
+                       vbd.back_type = 3;
+                       vbd.error = 0;
+
+                       if (asprintf(&path, 
"/local/domain/0/backend/vbd3/%u/%u/kthread-pid", domid, vbd.dev) < 0)
+                               continue;
+
+                       td3_pid = xs_read(node->handle->xshandle, XBT_NULL, 
path, NULL);
+
+                       free(path);
+
+                       if (td3_pid == NULL)
+                               continue;
+
+                       if (asprintf(&path, "/dev/shm/td3-%s/vbd-%u-%u", 
td3_pid, domid, vbd.dev) < 0) {
+                               free(td3_pid);
+                               continue;
+                       }
+
+                       if (read_attributes_vbd3(path, &vbd) < 0)
+                               vbd.error = 1;
+
+                       free(td3_pid);
+                       free(path);
+               }
                else
                {
                        vbd.error = 1;
diff --git a/tools/libs/stat/xenstat_priv.h b/tools/libs/stat/xenstat_priv.h
index 4eb44a8ebb84..c3a9635240e9 100644
--- a/tools/libs/stat/xenstat_priv.h
+++ b/tools/libs/stat/xenstat_priv.h
@@ -98,6 +98,22 @@ struct xenstat_vbd {
        unsigned long long wr_sects;
 };
 
+struct vbd3_stats {
+       uint32_t version;
+       uint32_t __pad;
+       uint64_t oo_reqs;
+       uint64_t read_reqs_submitted;
+       uint64_t read_reqs_completed;
+       uint64_t read_sectors;
+       uint64_t read_total_ticks;
+       uint64_t write_reqs_submitted;
+       uint64_t write_reqs_completed;
+       uint64_t write_sectors;
+       uint64_t write_total_ticks;
+       uint64_t io_errors;
+       uint64_t flags;
+};
+
 extern int xenstat_collect_networks(xenstat_node * node);
 extern void xenstat_uninit_networks(xenstat_handle * handle);
 extern int xenstat_collect_vbds(xenstat_node * node);
diff --git a/tools/xentop/xentop.c b/tools/xentop/xentop.c
index 0a2fab7f15a3..f5a456fd4dfd 100644
--- a/tools/xentop/xentop.c
+++ b/tools/xentop/xentop.c
@@ -1124,6 +1124,7 @@ void do_vbd(xenstat_domain *domain)
                "Unidentified",           /* number 0 */
                "BlkBack",           /* number 1 */
                "BlkTap",            /* number 2 */
+               "Tapdisk3"           /* number 3 */
        };
 
        num_vbds = xenstat_domain_num_vbds(domain);
-- 
2.42.0