Allow 'zpool replace' to use short device names

The 'zpool replace' command would fail when given a short name
because unlike on other platforms the short name cannot be
deterministically expanded to a single path.  Multiple path
prefixes must be checked and in addition the partition suffix
for whole disks is determined by the prefix.

To handle this complexity a zfs_strcmp_pathname() function was
added which takes either a short or fully qualified device name.
Short names will be expanded using the prefixes in the default
import search path, or the ZPOOL_IMPORT_PATH environment variable
if it's defined.  All posible expansions are then compared against
the comparison path.  Care is taken to strip redundant slashes to
ensure legitimate matches are not missed.

In the context of this work the existing zfs_resolve_shortname()
function was extended to consider the ZPOOL_IMPORT_PATH when set.
The zfs_append_partition() interface was also simplified to take
only a single buffer.

The vast majority of these changes rework existing Linux specific
code which was originally written to accomidate udev.  However,
there is some minimal cleanup which removes Illumos specific code.
This was done to improve readability but the basic flow and intent
of the upstream code was maintained.

These changes are the logical conclusion of the previos work to
adjust the 'zpool import' search behavior, see commit 44867b6a.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #544
Closes #976

1 files changed, 14 insertions, 25 deletions

diff --git a/lib/libzfs/libzfs_pool.c b/lib/libzfs/libzfs_pool.c
index 2198a828500a..75e883e4f440 100644
--- a/lib/libzfs/libzfs_pool.c
+++ b/lib/libzfs/libzfs_pool.c
@@ -1744,10 +1744,11 @@ vdev_to_nvlist_iter(nvlist_t *nv, nvlist_t *search, boolean_t *avail_spare,
 		/*
 		 * Search for the requested value. Special cases:
 		 *
-		 * - ZPOOL_CONFIG_PATH for whole disk entries.  These end in with a
-		 *   partition suffix "1", "-part1", or "p1".  The suffix is  hidden
-		 *   from the user, but included in the string, so this matches around
-		 *   it.
+		 * - ZPOOL_CONFIG_PATH for whole disk entries.  These end in
+		 *   "-part1", or "p1".  The suffix is hidden from the user,
+		 *   but included in the string, so this matches around it.
+		 * - ZPOOL_CONFIG_PATH for short names zfs_strcmp_shortname()
+		 *   is used to check all possible expanded paths.
 		 * - looking for a top-level vdev name (i.e. ZPOOL_CONFIG_TYPE).
 		 *
 		 * Otherwise, all other searches are simple string compares.
@@ -1757,15 +1758,9 @@ vdev_to_nvlist_iter(nvlist_t *nv, nvlist_t *search, boolean_t *avail_spare,
 
 			(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_WHOLE_DISK,
 			    &wholedisk);
-			if (wholedisk) {
-				char buf[MAXPATHLEN];
-
-				zfs_append_partition(srchval, buf, sizeof (buf));
-				if (strcmp(val, buf) == 0)
-					return (nv);
+			if (zfs_strcmp_pathname(srchval, val, wholedisk) == 0)
+				return (nv);
 
-				break;
-			}
 		} else if (strcmp(srchkey, ZPOOL_CONFIG_TYPE) == 0 && val) {
 			char *type, *idx, *end, *p;
 			uint64_t id, vdev_id;
@@ -1916,7 +1911,6 @@ nvlist_t *
 zpool_find_vdev(zpool_handle_t *zhp, const char *path, boolean_t *avail_spare,
     boolean_t *l2cache, boolean_t *log)
 {
-	char buf[MAXPATHLEN];
 	char *end;
 	nvlist_t *nvroot, *search, *ret;
 	uint64_t guid;
@@ -1928,12 +1922,6 @@ zpool_find_vdev(zpool_handle_t *zhp, const char *path, boolean_t *avail_spare,
 		verify(nvlist_add_uint64(search, ZPOOL_CONFIG_GUID, guid) == 0);
 	} else if (zpool_vdev_is_interior(path)) {
 		verify(nvlist_add_string(search, ZPOOL_CONFIG_TYPE, path) == 0);
-	} else if (path[0] != '/') {
-		if (zfs_resolve_shortname(path, buf, sizeof (buf)) < 0) {
-			nvlist_free(search);
-			return (NULL);
-		}
-		verify(nvlist_add_string(search, ZPOOL_CONFIG_PATH, buf) == 0);
 	} else {
 		verify(nvlist_add_string(search, ZPOOL_CONFIG_PATH, path) == 0);
 	}
@@ -3701,7 +3689,7 @@ read_efi_label(nvlist_t *config, diskaddr_t *sb)
 	if (nvlist_lookup_string(config, ZPOOL_CONFIG_PATH, &path) != 0)
 		return (err);
 
-	(void) snprintf(diskname, sizeof (diskname), "%s%s", RDISK_ROOT,
+	(void) snprintf(diskname, sizeof (diskname), "%s%s", DISK_ROOT,
 	    strrchr(path, '/'));
 	if ((fd = open(diskname, O_RDWR|O_DIRECT)) >= 0) {
 		struct dk_gpt *vtoc;
@@ -3839,8 +3827,7 @@ zpool_label_disk(libzfs_handle_t *hdl, zpool_handle_t *zhp, char *name)
 		start_block = NEW_START_BLOCK;
 	}
 
-	(void) snprintf(path, sizeof (path), "%s/%s%s", RDISK_ROOT, name,
-	    BACKUP_SLICE);
+	(void) snprintf(path, sizeof (path), "%s/%s", DISK_ROOT, name);
 
 	if ((fd = open(path, O_RDWR|O_DIRECT)) < 0) {
 		/*
@@ -3910,9 +3897,11 @@ zpool_label_disk(libzfs_handle_t *hdl, zpool_handle_t *zhp, char *name)
 	(void) close(fd);
 	efi_free(vtoc);
 
-	/* Wait for the first expected slice to appear. */
-	(void) snprintf(path, sizeof (path), "%s/%s%s%s", DISK_ROOT, name,
-	    isdigit(name[strlen(name)-1]) ? "p" : "", FIRST_SLICE);
+	/* Wait for the first expected partition to appear. */
+
+	(void) snprintf(path, sizeof (path), "%s/%s", DISK_ROOT, name);
+	(void) zfs_append_partition(path, MAXPATHLEN);
+
 	rval = zpool_label_disk_wait(path, 3000);
 	if (rval) {
 		zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "failed to "