[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: [dm-devel] sg_persist triggers block kernel event ???



It seems sg_persist is doing an "open rw => close" for --in commands, causing a kernel change-event.
I can not verify at the moment if the following patch would work ... comments ?

--- sg_persist.c.orig 2014-05-04 01:10:01.987981956 +0200
+++ sg_persist.c 2014-05-04 01:15:34.880008000 +0200
@@ -1029,6 +1029,8 @@
     struct sg_simple_inquiry_resp inq_resp;
     const char * cp;
     struct opts_t opts;
+    int omode = 0;
+    const char *omode_desc = NULL;
 
     memset(&opts, 0, sizeof(opts));
     opts.prin = 1;
@@ -1292,10 +1294,18 @@
         sg_cmds_close_device(sg_fd);
     }
 
-    if ((sg_fd = sg_cmds_open_device(device_name, 0 /* rw */,
+    if (opts.prin) {
+        omode = 1;
+        omode_desc = "ro";
+    } else {
+        omode = 0;
+        omode_desc = "rw";
+    }
+
+    if ((sg_fd = sg_cmds_open_device(device_name, omode,
                                      opts.verbose)) < 0) {
-        pr2serr("sg_persist: error opening file (rw): %s: %s\n", device_name,
-                safe_strerror(-sg_fd));
+        pr2serr("sg_persist: error opening file (%s): %s: %s\n", omode_desc,
+                device_name, safe_strerror(-sg_fd));
         return SG_LIB_FILE_ERROR;
     }
 
Regards,
Christophe Varoqui
www.opensvc.com


On Sat, May 3, 2014 at 10:12 PM, Christophe Varoqui <christophe varoqui opensvc com> wrote:
Hi list,

I observe this on a debian 7.5 server with a udevadm monitor running in the background :

# sg_persist -n -k /dev/sdbh
  PR generation=0x0, there are NO registered reservation keys

KERNEL[448809.342461] change   /devices/pci0000:20/0000:20:02.2/0000:24:00.0/host0/rport-0:0-3/target0:0:1/0:0:1:12/block/sdbh (block)
ACTION="">
DEVNAME=/dev/sdbh
DEVPATH=/devices/pci0000:20/0000:20:02.2/0000:24:00.0/host0/rport-0:0-3/target0:0:1/0:0:1:12/block/sdbh
DEVTYPE=disk
MAJOR=67
MINOR=176
SEQNUM=261605
SUBSYSTEM=block

Every sg_persist command, with any options, trigger events.

On this server with more than 200 scsi devices, each receiving one read-key and one read-reservation every 10 minutes, this triggers quite a eavy load caused by 2 udev triggers :

1/ multipath -v0 $devpath
2/ udisks-lvm-pv-export $pv_uuid


Question is, is it normal for a "--in" sg_persist command to trigger a change event on the scsi device ? If not, what we can do about it ?

Best regards,
Christophe Varoqui



[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]