- Add md_provsize field to metadata, which will help with

  shared-last-sector problem.
  After this change, even if there is more than one provider with the same
  last sector, the proper one will be chosen based on its size.
  It still doesn't fix the 'c' partition problem (when da0s1 can be confused
  with da0s1c) and situation when 'a' partition starts at offset 0
  (then da0s1a can be confused with da0s1 and da0s1c). One can use '-h'
  option there, when creating device or avoid sharing last sector.
  Actually, when providers share the same last sector and their size is equal,
  they provide exactly the same data, so the name (da0s1, da0s1a, da0s1c)
  isn't important at all.
- Provide backward compatibility.
- Update copyright's year.

MFC after:	1 week

2 files changed, 14 insertions, 1 deletions

diff --git a/sys/geom/shsec/g_shsec.c b/sys/geom/shsec/g_shsec.c
index 5bc1ba8..acfa8fb 100644
--- a/sys/geom/shsec/g_shsec.c
+++ b/sys/geom/shsec/g_shsec.c
@@ -660,8 +660,17 @@ g_shsec_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
 		    pp->name);
 		return (NULL);
 	}
+	/*
+	 * Backward compatibility:
+	 */
+	/* There was no md_provsize field in earlier versions of metadata. */
+	if (md.md_version < 1)
+		md.md_provsize = pp->mediasize;
+
 	if (md.md_provider[0] != '\0' && strcmp(md.md_provider, pp->name) != 0)
 		return (NULL);
+	if (md.md_provsize != pp->mediasize)
+		return (NULL);
 
 	/*
 	 * Let's check if device already exists.
diff --git a/sys/geom/shsec/g_shsec.h b/sys/geom/shsec/g_shsec.h
index 08b8a29..af2e8a7 100644
--- a/sys/geom/shsec/g_shsec.h
+++ b/sys/geom/shsec/g_shsec.h
@@ -37,8 +37,9 @@
 /*
  * Version history:
  * 0 - Initial version number.
+ * 1 - Added md_provsize field to metadata.
  */
-#define	G_SHSEC_VERSION	0
+#define	G_SHSEC_VERSION	1
 
 #ifdef _KERNEL
 #define	G_SHSEC_BFLAG_FIRST	0x1
@@ -85,6 +86,7 @@ struct g_shsec_metadata {
 	uint16_t	md_no;		/* Disk number. */
 	uint16_t	md_all;		/* Number of all disks. */
 	char		md_provider[16]; /* Hardcoded provider. */
+	uint64_t	md_provsize;	/* Provider's size. */
 };
 static __inline void
 shsec_metadata_encode(const struct g_shsec_metadata *md, u_char *data)
@@ -97,6 +99,7 @@ shsec_metadata_encode(const struct g_shsec_metadata *md, u_char *data)
 	le16enc(data + 40, md->md_no);
 	le16enc(data + 42, md->md_all);
 	bcopy(md->md_provider, data + 44, sizeof(md->md_provider));
+	le64enc(data + 60, md->md_provsize);
 }
 static __inline void
 shsec_metadata_decode(const u_char *data, struct g_shsec_metadata *md)
@@ -109,5 +112,6 @@ shsec_metadata_decode(const u_char *data, struct g_shsec_metadata *md)
 	md->md_no = le16dec(data + 40);
 	md->md_all = le16dec(data + 42);
 	bcopy(data + 44, md->md_provider, sizeof(md->md_provider));
+	md->md_provsize = le64dec(data + 60);
 }
 #endif	/* _G_SHSEC_H_ */