Add support for devid and phys_path keys in vdev disk labels

This is foundational work for ZED.

Updates a leaf vdev's persistent device strings on Linux platform

* only applies for a dedicated leaf vdev (aka whole disk)
* updated during pool create|add|attach|import
* used for matching device matching during auto-{online,expand,replace}
* stored in a leaf disk config label (i.e. alongside 'path' NVP)
* can opt-out using env var ZFS_VDEV_DEVID_OPT_OUT=YES

Some examples:

    path: '/dev/sdb1'
    devid: 'scsi-350000394a8ca4fbc-part1'
    phys_path: 'pci-0000:04:00.0-sas-0x50000394a8ca4fbf-lun-0'

    path: '/dev/mapper/mpatha'
    devid: 'dm-uuid-mpath-35000c5006304de3f'

Signed-off-by: Don Brady <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #2856
Closes #3978
Closes #4416

2 files changed, 94 insertions, 55 deletions

diff --git a/tests/zfs-tests/cmd/devname2devid/Makefile.am b/tests/zfs-tests/cmd/devname2devid/Makefile.am
index 2eb03e9cf..55811b7a7 100644
--- a/tests/zfs-tests/cmd/devname2devid/Makefile.am
+++ b/tests/zfs-tests/cmd/devname2devid/Makefile.am
@@ -1,7 +1,7 @@
 include $(top_srcdir)/config/Rules.am
 
-pkgdatadir = $(datadir)/@PACKAGE@/zfs-tests/bin
+pkgexecdir = $(datadir)/@PACKAGE@/zfs-tests/bin
 
-# DISABLED: Not supported under Linux
-# pkgdata_PROGRAMS = devname2devid
-# devname2devid_SOURCES = devname2devid.c
+pkgexec_PROGRAMS = devname2devid
+devname2devid_SOURCES = devname2devid.c
+devname2devid_LDADD = -ludev
diff --git a/tests/zfs-tests/cmd/devname2devid/devname2devid.c b/tests/zfs-tests/cmd/devname2devid/devname2devid.c
index fd3287491..59fbcdddb 100644
--- a/tests/zfs-tests/cmd/devname2devid/devname2devid.c
+++ b/tests/zfs-tests/cmd/devname2devid/devname2devid.c
@@ -22,27 +22,85 @@
 /*
  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
+ *
+ * Copyright (c) 2016, Intel Corporation.
  */
 
 #include <sys/types.h>
+#include <sys/param.h>
 #include <sys/stat.h>
-#include <devid.h>
+#include <libudev.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <fcntl.h>
 
 /*
+ * Linux persistent device strings for vdev labels
+ *
+ * based on udev_device_get_devid() at zfs/lib/libzfs/libzfs_import.c
+ */
+
+#define	DEV_BYID_PATH	"/dev/disk/by-id/"
+
+static int
+udev_device_get_devid(struct udev_device *dev, char *bufptr, size_t buflen)
+{
+	struct udev_list_entry *entry;
+	const char *bus;
+	char devbyid[MAXPATHLEN];
+
+	/* The bus based by-id path is preferred */
+	bus = udev_device_get_property_value(dev, "ID_BUS");
+
+	if (bus == NULL) {
+		const char *dm_uuid;
+
+		/*
+		 * For multipath nodes use the persistent uuid based identifier
+		 *
+		 * Example: 'dm-uuid-mpath-35000c5006304de3f'
+		 */
+		dm_uuid = udev_device_get_property_value(dev, "DM_UUID");
+		if (dm_uuid != NULL) {
+			(void) snprintf(bufptr, buflen, "dm-uuid-%s", dm_uuid);
+			return (0);
+		}
+		return (ENODATA);
+	}
+
+	/*
+	 * locate the bus specific by-id link
+	 *
+	 * Example: 'scsi-MG03SCA300_350000494a8cb3d67-part1'
+	 */
+	(void) snprintf(devbyid, sizeof (devbyid), "%s%s-", DEV_BYID_PATH, bus);
+	entry = udev_device_get_devlinks_list_entry(dev);
+	while (entry != NULL) {
+		const char *name;
+
+		name = udev_list_entry_get_name(entry);
+		if (strncmp(name, devbyid, strlen(devbyid)) == 0) {
+			name += strlen(DEV_BYID_PATH);
+			(void) stpncpy(bufptr, name, buflen);
+			return (0);
+		}
+		entry = udev_list_entry_get_next(entry);
+	}
+
+	return (ENODATA);
+}
+
+/*
  * Usage: devname2devid <devicepath>
  *
  * Examples:
- *	# ./devname2devid /dev/dsk/c1t4d0s0
- *	devid id1,sd@SSEAGATE_ST318404LSUN18G_3BT2G0Z300002146G4CR/a
- *	# ./devname2devid /dev/dsk/c1t4d0
- *	devid id1,sd@SSEAGATE_ST318404LSUN18G_3BT2G0Z300002146G4CR/wd
- *	# ./devname2devid /dev/dsk/c1t4d0s1
- *	devid id1,sd@SSEAGATE_ST318404LSUN18G_3BT2G0Z300002146G4CR/b
- *	#
+ * # ./devname2devid /dev/sda1
+ * devid scsi-350000394a8caede4-part1
+ *
+ * # ./devname2devid /dev/dm-1
+ * devid: 'dm-uuid-mpath-35000c5006304de3f'
  *
  * This program accepts a disk or disk slice path and prints a
  * device id.
@@ -55,66 +113,47 @@
 int
 main(int argc, char *argv[])
 {
-	int		fd;
-	ddi_devid_t	devid;
-	char		*minor_name, *devidstr, *device;
-#ifdef DEBUG
-	devid_nmlist_t  *list = NULL;
-	char		*search_path;
-	int		i;
-#endif
+	struct udev *udev;
+	struct udev_device *dev = NULL;
+	char devid[128], nodepath[MAXPATHLEN];
+	char *device, *sysname;
+	int ret;
 
 	if (argc == 1) {
-		(void) printf("%s <devicepath> [search path]\n",
-		    argv[0]);
+		(void) printf("%s <devicepath> [search path]\n", argv[0]);
 		exit(1);
 	}
 	device = argv[1];
 
-	if ((fd = open(device, O_RDONLY|O_NDELAY)) < 0) {
-		perror(device);
-		exit(1);
-	}
-	if (devid_get(fd, &devid) != 0) {
-		perror("devid_get");
-		exit(1);
-	}
-	if (devid_get_minor_name(fd, &minor_name) != 0) {
-		perror("devid_get_minor_name");
-		exit(1);
-	}
-	if ((devidstr = devid_str_encode(devid, minor_name)) == 0) {
-		perror("devid_str_encode");
+	if ((udev = udev_new()) == NULL) {
+		perror("udev_new");
 		exit(1);
 	}
 
-	(void) printf("devid %s\n", devidstr);
-
-	devid_str_free(devidstr);
-
-#ifdef DEBUG
-	if (argc == 3) {
-		search_path = argv[2];
-	} else {
-		search_path = "/dev/rdsk";
+	/* resolve path to a runtime device node instance */
+	if (realpath(device, nodepath) == NULL) {
+		perror("realpath");
+		exit(1);
 	}
+	sysname = strrchr(nodepath, '/') + 1;
 
-	if (devid_deviceid_to_nmlist(search_path, devid, DEVID_MINOR_NAME_ALL,
-	    &list)) {
-		perror("devid_deviceid_to_nmlist");
+	if ((dev = udev_device_new_from_subsystem_sysname(udev, "block",
+	    sysname)) == NULL) {
+		perror(sysname);
 		exit(1);
 	}
 
-	/* loop through list and process device names and numbers */
-	for (i = 0; list[i].devname != NULL; i++) {
-		(void) printf("devname: %s %p\n", list[i].devname, list[i].dev);
+	if ((ret = udev_device_get_devid(dev, devid, sizeof (devid))) != 0) {
+		udev_device_unref(dev);
+		errno = ret;
+		perror(sysname);
+		exit(1);
 	}
-	devid_free_nmlist(list);
 
-#endif /* DEBUG */
+	(void) printf("devid %s\n", devid);
 
-	devid_str_free(minor_name);
-	devid_free(devid);
+	udev_device_unref(dev);
+	udev_unref(udev);
 
 	return (0);
 }