Add a priority label to the device structure, so we can give

preference to EVMS and LVM devices when searching for a device
matching a particular LABEL or UUID in the blkid library.

9 files changed, 143 insertions, 100 deletions

diff --git a/lib/blkid/ChangeLog b/lib/blkid/ChangeLog
index b73e5aa3..79bdb2a3 100644
--- a/lib/blkid/ChangeLog
+++ b/lib/blkid/ChangeLog
@@ -1,3 +1,36 @@
+2003-02-14  Theodore Ts'o  <tytso@mit.edu>
+
+	* Makefile.in (blkid): When building the blkid, don't link against
+		the shared blkid library; link only against the static
+		blkid library.
+
+	* blkidP.h (struct blkid_struct_dev): Remove bid_size and
+		bid_devsize (since they aren't used any more) and add
+		bid_pri to the device structure.
+
+	* devname.c (probe_one, lvm_probe_all, evms_probe_all,
+		blkid_probe_all): Set the bid_pri filed in the device
+		structure depending on type of device so that EVMS, LVM,
+		and MD devices get priority over normal devices.
+
+	* tag.c (blkid_find_dev_with_tag): When looking for a device that
+		matches the search criteria, return the one with the
+		largest priority (bid_pri).
+
+	* save.c (save_dev): Write out the PRI tag from bid_pri.
+
+	* read.c (parse_tag): Parse the PRI tag and store its value in
+		bid_pri.
+
+	* probe.c (blkid_verify_devname): If the device does not exist
+		(open returns ENOENT), treat this as a fatal error and
+		release the device.  After verifying the device, set the
+		cache as being modified so the changes are written out.
+
+	* resolve.c (main): Change the test driver to get a blkid cache
+		and pass it to blkid_get_tagname_devname and
+		blkid_get_token, as the cache is no longer optional.
+
 2003-02-12  Theodore Ts'o  <tytso@mit.edu>
 
 	* blkid.h, blkidP.h, cache.c, dev.c, devname.c, devno.c, probe.c,
diff --git a/lib/blkid/Makefile.in b/lib/blkid/Makefile.in
index 42528357..17e772e3 100644
--- a/lib/blkid/Makefile.in
+++ b/lib/blkid/Makefile.in
@@ -101,8 +101,8 @@ tst_save: $(srcdir)/save.c $(DEPLIBS_BLKID)
 	$(CC) -Wall $(ALL_CFLAGS) -c $(top_srcdir)/misc/blkid.c \
 		-o ../../misc/blkid.o
 
-blkid: ../../misc/blkid.o libblkid.a $(LIBBLKID) $(LIBUUID)
-	$(CC) -Wall -o blkid ../../misc/blkid.o libblkid.a $(LIBBLKID) $(LIBUUID)
+blkid: ../../misc/blkid.o libblkid.a $(LIBUUID)
+	$(CC) -Wall -o blkid ../../misc/blkid.o libblkid.a $(LIBUUID)
 
 check:: tst_cache tst_devname tst_devno tst_getsize tst_probe \
  tst_read tst_resolve tst_save
diff --git a/lib/blkid/blkidP.h b/lib/blkid/blkidP.h
index 5a998029..423e7dea 100644
--- a/lib/blkid/blkidP.h
+++ b/lib/blkid/blkidP.h
@@ -33,8 +33,7 @@ struct blkid_struct_dev
 	blkid_cache		bid_cache;	/* Dev belongs to this cache */
 	char			*bid_name;	/* Device inode pathname */
 	char			*bid_type;	/* Preferred device TYPE */
-	blkid_loff_t		bid_size;	/* Filesystem size in bytes */
-	blkid_loff_t		bid_devsize;	/* Device size in bytes */
+	int			bid_pri;	/* Device priority */
 	dev_t			bid_devno;	/* Device major/minor number */
 	time_t			bid_time;	/* Last update time of device */
 	unsigned int		bid_id;		/* Unique cache id for device */
@@ -89,7 +88,7 @@ struct blkid_struct_cache
 	struct list_head	bic_devs;	/* List head of all devices */
 	struct list_head	bic_tags;	/* List head of all tag types */
 	time_t			bic_time;	/* Last probe time */
-	unsigned int		bic_idmax;	/* Highest ID assigned */
+p	unsigned int		bic_idmax;	/* Highest ID assigned */
 	unsigned int		bic_flags;	/* Status flags of the cache */
 	char			*bic_filename;	/* filename of cache */
 };
@@ -112,6 +111,13 @@ extern const char *blkid_devdirs[];
 #define BLKID_ERR_PARAM	22
 #define BLKID_ERR_BIG	27
 
+/*
+ * Priority settings for different types of devices
+ */
+#define BLKID_PRI_EVMS	30
+#define BLKID_PRI_LVM	20
+#define BLKID_PRI_MD	10
+
 #if defined(TEST_PROGRAM)
 #define DEBUG
 #endif
@@ -158,7 +164,7 @@ static inline void DEB_DUMP_DEV(blkid_dev dev)
 	printf("  dev: DEVNO=\"0x%0Lx\"\n", dev->bid_devno);
 	printf("  dev: ID=\"%u\"\n", dev->bid_id);
 	printf("  dev: TIME=\"%lu\"\n", dev->bid_time);
-	printf("  dev: size = %Lu\n", dev->bid_size);
+	printf("  dev: PRI=\"%d\"\n", dev->bid_pri);
 	printf("  dev: flags = 0x%08X\n", dev->bid_flags);
 
 	list_for_each(p, &dev->bid_tags) {
diff --git a/lib/blkid/devname.c b/lib/blkid/devname.c
index 6cb3a8e8..ef001d13 100644
--- a/lib/blkid/devname.c
+++ b/lib/blkid/devname.c
@@ -86,8 +86,8 @@ blkid_dev blkid_get_devname(blkid_cache cache, const char *devname,
 /*
  * Probe a single block device to add to the device cache.
  */
-static blkid_dev probe_one(blkid_cache cache, const char *ptname,
-			    dev_t devno)
+static void probe_one(blkid_cache cache, const char *ptname,
+		      dev_t devno, int pri)
 {
 	blkid_dev dev = NULL;
 	struct list_head *p;
@@ -104,7 +104,7 @@ static blkid_dev probe_one(blkid_cache cache, const char *ptname,
 		}
 	}
 	if (dev && dev->bid_devno == devno)
-		return dev;
+		goto set_pri;
 
 	/*
 	 * Take a quick look at /dev/ptname for the device number.  We check
@@ -119,7 +119,7 @@ static blkid_dev probe_one(blkid_cache cache, const char *ptname,
 		sprintf(device, "%s/%s", *dir, ptname);
 		if ((dev = blkid_get_devname(cache, device, BLKID_DEV_FIND)) &&
 		    dev->bid_devno == devno)
-			return dev;
+			goto set_pri;
 
 		if (stat(device, &st) == 0 && st.st_rdev == devno) {
 			devname = blkid_strdup(device);
@@ -129,12 +129,16 @@ static blkid_dev probe_one(blkid_cache cache, const char *ptname,
 	if (!devname) {
 		devname = blkid_devno_to_devname(devno);
 		if (!devname)
-			return NULL;
+			return;
 	}
 	dev = blkid_get_devname(cache, devname, BLKID_DEV_NORMAL);
 	free(devname);
 
-	return dev;
+set_pri:
+	if (!pri && !strncmp(ptname, "md", 2))
+		pri = BLKID_PRI_MD;
+	dev->bid_pri = pri;
+	return;
 }
 
 #define PROC_PARTITIONS "/proc/partitions"
@@ -223,7 +227,7 @@ static void lvm_probe_all(blkid_cache cache)
 			sprintf(lvm_device, "%s/%s", vg_name, lv_name);
 			DBG(printf("LVM dev %s: devno 0x%04X\n",
 				   lvm_device, dev));
-			probe_one(cache, lvm_device, dev);
+			probe_one(cache, lvm_device, dev, BLKID_PRI_LVM);
 			free(lvm_device);
 		}
 		closedir(lv_list);
@@ -254,7 +258,7 @@ evms_probe_all(blkid_cache cache)
 		DBG(printf("Checking partition %s (%d, %d)\n",
 			   device, ma, mi));
 
-		probe_one(cache, device, makedev(ma, mi));
+		probe_one(cache, device, makedev(ma, mi), BLKID_PRI_EVMS);
 		num++;
 	}
 	fclose(procpt);
@@ -267,7 +271,14 @@ evms_probe_all(blkid_cache cache)
 int blkid_probe_all(blkid_cache cache)
 {
 	FILE *proc;
-	int firstPass;
+	char line[1024];
+	char ptname0[128], ptname1[128], *ptname = 0;
+	char *ptnames[2] = { ptname0, ptname1 };
+	dev_t devs[2];
+	int ma, mi;
+	unsigned long long sz;
+	int lens[2] = { 0, 0 };
+	int which = 0, last = 0;
 
 	if (!cache)
 		return -BLKID_ERR_PARAM;
@@ -276,9 +287,7 @@ int blkid_probe_all(blkid_cache cache)
 	    time(0) - cache->bic_time < BLKID_PROBE_INTERVAL)
 		return 0;
 
-	if (evms_probe_all(cache))
-		goto finish;
-
+	evms_probe_all(cache);
 #ifdef VG_DIR
 	lvm_probe_all(cache);
 #endif
@@ -287,76 +296,55 @@ int blkid_probe_all(blkid_cache cache)
 	if (!proc)
 		return -BLKID_ERR_PROC;
 
-	for (firstPass = 1; firstPass >= 0; firstPass--) {
-		char line[1024];
-		char ptname0[128], ptname1[128], *ptname = 0;
-		char *ptnames[2] = { ptname0, ptname1 };
-		dev_t devs[2];
-		int ma, mi;
-		unsigned long long sz;
-		int lens[2] = { 0, 0 };
-		int handleOnFirst;
-		int which = 0, last = 0;
-
-		fseek(proc, 0, SEEK_SET);
-
-		while (fgets(line, sizeof(line), proc)) {
-			last = which;
-			which ^= 1;
-			ptname = ptnames[which];
-
-			if (sscanf(line, " %d %d %lld %128[^\n ]",
-				   &ma, &mi, &sz, ptname) != 4)
-				continue;
-			devs[which] = makedev(ma, mi);
-
-			DBG(printf("read partition name %s\n", ptname));
-
-			/* look only at md devices on first pass */
-			handleOnFirst = !strncmp(ptname, "md", 2);
-			if (firstPass != handleOnFirst)
-				continue;
+	while (fgets(line, sizeof(line), proc)) {
+		last = which;
+		which ^= 1;
+		ptname = ptnames[which];
 
-			/* Skip whole disk devs unless they have no partitions
-			 * If we don't have a partition on this dev, also
-			 * check previous dev to see if it didn't have a partn.
-			 * heuristic: partition name ends in a digit.
-			 *
-			 * Skip extended partitions.
-			 * heuristic: size is 1
-			 *
-			 * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
-			 */
-
-			lens[which] = strlen(ptname);
-			if (isdigit(ptname[lens[which] - 1])) {
-				DBG(printf("partition dev %s, devno 0x%04X\n",
-					   ptname, devs[which]));
-
-				if (sz > 1)
-					probe_one(cache, ptname, devs[which]);
-				lens[which] = 0;
-				lens[last] = 0;
-			} else if (lens[last] &&
-				   strncmp(ptnames[last], ptname,
-					   lens[last])) {
-				DBG(printf("whole dev %s, devno 0x%04X\n",
-					   ptname, devs[last]));
-				probe_one(cache, ptname, devs[last]);
-				lens[last] = 0;
-			}
+		if (sscanf(line, " %d %d %lld %128[^\n ]",
+			   &ma, &mi, &sz, ptname) != 4)
+			continue;
+		devs[which] = makedev(ma, mi);
+
+		DBG(printf("read partition name %s\n", ptname));
+
+		/* Skip whole disk devs unless they have no partitions
+		 * If we don't have a partition on this dev, also
+		 * check previous dev to see if it didn't have a partn.
+		 * heuristic: partition name ends in a digit.
+		 *
+		 * Skip extended partitions.
+		 * heuristic: size is 1
+		 *
+		 * FIXME: skip /dev/{ida,cciss,rd} whole-disk devs
+		 */
+
+		lens[which] = strlen(ptname);
+		if (isdigit(ptname[lens[which] - 1])) {
+			DBG(printf("partition dev %s, devno 0x%04X\n",
+				   ptname, devs[which]));
+
+			if (sz > 1)
+				probe_one(cache, ptname, devs[which], 0);
+			lens[which] = 0;
+			lens[last] = 0;
+		} else if (lens[last] && strncmp(ptnames[last], ptname,
+						 lens[last])) {
+			DBG(printf("whole dev %s, devno 0x%04X\n",
+				   ptnames[last], devs[last]));
+			probe_one(cache, ptnames[last], devs[last], 0);
+			lens[last] = 0;
 		}
-
-		/* Handle the last device if it wasn't partitioned */
-		if (lens[which])
-			probe_one(cache, ptname, devs[which]);
 	}
+
+	/* Handle the last device if it wasn't partitioned */
+	if (lens[which])
+		probe_one(cache, ptname, devs[which], 0);
+
 	fclose(proc);
 
-finish:
 	cache->bic_time = time(0);
 	cache->bic_flags |= BLKID_BIC_FL_PROBED;
-
 	return 0;
 }
 
diff --git a/lib/blkid/probe.c b/lib/blkid/probe.c
index eeb544c6..f703052a 100644
--- a/lib/blkid/probe.c
+++ b/lib/blkid/probe.c
@@ -344,11 +344,12 @@ blkid_dev blkid_verify_devname(blkid_cache cache, blkid_dev dev)
 				       diff < BLKID_PROBE_INTERVAL))
 		return dev;
 
-	DBG(printf("need to revalidate %s\n", dev->bid_name));
+	DBG(printf("need to revalidate %s (time since last check %lu)\n", 
+		   dev->bid_name, diff));
 
 	if (((fd = open(dev->bid_name, O_RDONLY)) < 0) ||
 	    (fstat(fd, &st) < 0) || !S_ISBLK(st.st_mode)) {
-		if (errno == ENXIO || errno == ENODEV) {
+		if (errno == ENXIO || errno == ENODEV || errno == ENOENT) {
 			blkid_free_dev(dev);
 			return NULL;
 		}
@@ -429,6 +430,7 @@ found_type:
 		dev->bid_devno = st.st_rdev;
 		dev->bid_time = time(0);
 		dev->bid_flags |= BLKID_BID_FL_VERIFIED;
+		cache->bic_flags |= BLKID_BIC_FL_CHANGED;
 
 		blkid_set_tag(dev, "TYPE", type, 0, 1);
 		if (sec_type)
diff --git a/lib/blkid/read.c b/lib/blkid/read.c
index 7c9c4d42..ce52d832 100644
--- a/lib/blkid/read.c
+++ b/lib/blkid/read.c
@@ -313,6 +313,8 @@ static int parse_tag(blkid_cache cache, blkid_dev dev, char **cp)
 			cache->bic_idmax = dev->bid_id;
 	} else if (!strcmp(name, "DEVNO"))
 		dev->bid_devno = STRTOULL(value, 0, 0);
+	else if (!strcmp(name, "PRI"))
+		dev->bid_pri = strtol(value, 0, 0);
 	else if (!strcmp(name, "TIME"))
 		/* FIXME: need to parse a long long eventually */
 		dev->bid_time = strtol(value, 0, 0);
diff --git a/lib/blkid/resolve.c b/lib/blkid/resolve.c
index 19478ed3..fca1e168 100644
--- a/lib/blkid/resolve.c
+++ b/lib/blkid/resolve.c
@@ -44,9 +44,6 @@ char *blkid_get_tagname_devname(blkid_cache cache, const char *tagname,
 	if (!devname)
 		return NULL;
 
-	if (!cache)
-		DBG(printf("no cache given, direct device probe\n"));
-
 	if ((dev = blkid_get_devname(cache, devname, BLKID_DEV_NORMAL)) &&
 	    (found = blkid_find_tag_dev(dev, tagname)))
 		ret = blkid_strdup(found->bit_val);
@@ -113,6 +110,7 @@ errout:
 int main(int argc, char **argv)
 {
 	char *value;
+	blkid_cache cache;
 
 	if (argc != 2 && argc != 3) {
 		fprintf(stderr, "Usage:\t%s tagname=value\n"
@@ -122,14 +120,20 @@ int main(int argc, char **argv)
 			argv[0], argv[0]);
 		exit(1);
 	}
+	if (blkid_get_cache(&cache, 0) < 0) {
+		fprintf(stderr, "Couldn't get blkid cache\n");
+		exit(1);
+	}
+	
 	if (argv[2]) {
-		value = blkid_get_tagname_devname(NULL, argv[1], argv[2]);
+		value = blkid_get_tagname_devname(cache, argv[1], argv[2]);
 		printf("%s has tag %s=%s\n", argv[2], argv[1],
 		       value ? value : "<missing>");
 	} else {
-		value = blkid_get_token(NULL, argv[1], NULL);
+		value = blkid_get_token(cache, argv[1], NULL);
 		printf("%s has tag %s\n", value ? value : "<none>", argv[1]);
 	}
+	blkid_put_cache(cache);
 	return value ? 0 : 1;
 }
 #endif
diff --git a/lib/blkid/save.c b/lib/blkid/save.c
index 5a8771e7..5de07190 100644
--- a/lib/blkid/save.c
+++ b/lib/blkid/save.c
@@ -45,6 +45,8 @@ static int save_dev(blkid_dev dev, FILE *file)
 		"<device TYPE=\"%s\" DEVNO=\"0x%04lx\" ID=\"%d\" TIME=\"%lu\"",
 		dev->bid_type, (unsigned long) dev->bid_devno,
 		dev->bid_id, dev->bid_time);
+	if (dev->bid_pri)
+		fprintf(file, " PRI=\"%d\"", dev->bid_pri);
 	list_for_each(p, &dev->bid_tags) {
 		blkid_tag tag = list_entry(p, struct blkid_struct_tag, bit_tags);
 		if (strcmp(tag->bit_name, "TYPE"))
diff --git a/lib/blkid/tag.c b/lib/blkid/tag.c
index 9bb99e14..3948a1e6 100644
--- a/lib/blkid/tag.c
+++ b/lib/blkid/tag.c
@@ -306,11 +306,9 @@ extern void blkid_tag_iterate_end(blkid_tag_iterate iter)
 
 /*
  * This function returns a device which matches a particular
- * type/value pair.  Its behaviour is currently undefined if there is
- * more than one device which matches the search specification.
- * In the future we may have some kind of preference scheme so that if
- * there is more than one match for a given label/uuid (for example in
- * the case of snapshots) we return the preferred device.
+ * type/value pair.  If there is more than one device that matches the
+ * search specification, it returns the one with the highest priority
+ * value.  This allows us to give preference to EVMS or LVM devices.
  *
  * XXX there should also be an interface which uses an iterator so we
  * can get all of the devices which match a type/value search parameter.
@@ -319,7 +317,9 @@ extern blkid_dev blkid_find_dev_with_tag(blkid_cache cache,
 					 const char *type,
 					 const char *value)
 {
-	blkid_tag head = 0, found = 0;
+	blkid_tag	head, found;
+	blkid_dev	dev;
+	int		pri;
 	struct list_head *p;
 
 	if (!cache || !type || !value)
@@ -328,24 +328,30 @@ extern blkid_dev blkid_find_dev_with_tag(blkid_cache cache,
 	DBG(printf("looking for %s=%s in cache\n", type, value));
 	
 try_again:
-	if (!head)
-		head = blkid_find_head_cache(cache, type);
+	pri = -1;
+	found = 0;
+	head = blkid_find_head_cache(cache, type);
 
 	if (head) {
 		list_for_each(p, &head->bit_names) {
 			blkid_tag tmp = list_entry(p, struct blkid_struct_tag, 
 						   bit_names);
 
-			if (!strcmp(tmp->bit_val, value)) {
+			if (!strcmp(tmp->bit_val, value) &&
+			    tmp->bit_dev->bid_pri > pri) {
 				found = tmp;
-				break;
+				dev = found->bit_dev;
+				pri = dev->bid_pri;
 			}
 		}
 	}
+	dev = blkid_verify_devname(cache, dev);
+	if (dev && strcmp(found->bit_val, value))
+		dev = 0;
 
-	if ((!head || !found) && !(cache->bic_flags & BLKID_BIC_FL_PROBED)) {
+	if ((!head || !dev) && !(cache->bic_flags & BLKID_BIC_FL_PROBED)) {
 		blkid_probe_all(cache);
 		goto try_again;
 	}
-	return (found ? found->bit_dev : NULL);
+	return dev;
 }