call_usermodehelper() should wait for process

As of Linux 3.4 the UMH_WAIT_* constants were renumbered. In particular, the meaning of "1" changed from UMH_WAIT_PROC (wait for process to complete), to UMH_WAIT_EXEC (wait for the exec, but not the process). A number of call sites used the number 1 instead of the constant name, so the behavior was not as expected on kernels with this change. One visible consequence of this change was that processes accessing automounted snapshots received an ELOOP error because they failed to wait for zfs.mount to complete. Signed-off-by: Brian Behlendorf <[email protected]> Closes openzfs#816
reineking · Jan 10, 2013 · 761394b · 761394b
1 parent 1c50c99
commit 761394b
Show file tree

Hide file tree

Showing 3 changed files with 4 additions and 4 deletions.
diff --git a/module/zfs/vdev_disk.c b/module/zfs/vdev_disk.c
@@ -159,7 +159,7 @@ vdev_elevator_switch(vdev_t *v, char *elevator)
 		char *envp[] = { NULL };
 
 		argv[2] = kmem_asprintf(SET_SCHEDULER_CMD, device, elevator);
-		error = call_usermodehelper(argv[0], argv, envp, 1);
+		error = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
 		strfree(argv[2]);
 	}
 #endif /* HAVE_ELEVATOR_CHANGE */

diff --git a/module/zfs/zfs_ctldir.c b/module/zfs/zfs_ctldir.c
@@ -696,7 +696,7 @@ __zfsctl_unmount_snapshot(zfs_snapentry_t *sep, int flags)
 
 	argv[2] = kmem_asprintf(SET_UNMOUNT_CMD,
 	    flags & MNT_FORCE ? "-f " : "", sep->se_path);
-	error = call_usermodehelper(argv[0], argv, envp, 1);
+	error = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
 	strfree(argv[2]);
 
 	/*
@@ -822,7 +822,7 @@ zfsctl_mount_snapshot(struct path *path, int flags)
 	 * to safely abort the automount.  This should be very rare.
 	 */
 	argv[2] = kmem_asprintf(SET_MOUNT_CMD, full_name, full_path);
-	error = call_usermodehelper(argv[0], argv, envp, 1);
+	error = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
 	strfree(argv[2]);
 	if (error) {
 		printk("ZFS: Unable to automount %s at %s: %d\n",

diff --git a/module/zpios/pios.c b/module/zpios/pios.c
@@ -92,7 +92,7 @@ int zpios_upcall(char *path, char *phase, run_args_t *run_args, int rc)
         envp[2] = "PATH=/sbin:/usr/sbin:/bin:/usr/bin";
         envp[3] = NULL;
 
-        return call_usermodehelper(path, argv, envp, 1);
+        return call_usermodehelper(path, argv, envp, UMH_WAIT_PROC);
 }
 
 static uint64_t