From 6c7e04f0f30d7631dc9819205fd517bee9af1967 Mon Sep 17 00:00:00 2001
From: "Andrey V. Elsukov" <ae@FreeBSD.org>
Date: Sun, 15 May 2011 16:16:48 +0000
Subject: [PATCH] Some partitioning schemes want to have partitions that are
 aligned with geometry. And they do recalculation of user specified
 parameters. MBR, PC98, VTOC8, EBR schemes are doing that. For these schemes
 an auto alignment feature (ie. gpart add -a alignment) would not work. But it
 can work for GPT and BSD schemes. BSD scheme usualy is created inside MBR, so
 we can use knowledge about offset of MBR partition to calculate aligned
 values for BSD partitions.

Use "offset" attribute of the parent provider for better alignment.

MFC after:	2 weeks
---
 sbin/geom/class/part/geom_part.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/sbin/geom/class/part/geom_part.c b/sbin/geom/class/part/geom_part.c
index 81d02914f9d1..19d1502fbe7d 100644
--- a/sbin/geom/class/part/geom_part.c
+++ b/sbin/geom/class/part/geom_part.c
@@ -416,7 +416,7 @@ gpart_autofill(struct gctl_req *req)
 	struct gprovider *pp;
 	off_t first, last, a_first;
 	off_t size, start, a_lba;
-	off_t lba, len, alignment;
+	off_t lba, len, alignment, offset;
 	uintmax_t grade;
 	const char *s;
 	int error, has_size, has_start, has_alignment;
@@ -467,8 +467,6 @@ gpart_autofill(struct gctl_req *req)
 		error = g_parse_lba(s, pp->lg_sectorsize, &size);
 		if (error)
 			errc(EXIT_FAILURE, error, "Invalid size param");
-		if (size > alignment)
-			size = ALIGNDOWN(size, alignment);
 	}
 
 	s = gctl_get_ascii(req, "start");
@@ -478,22 +476,29 @@ gpart_autofill(struct gctl_req *req)
 		error = g_parse_lba(s, pp->lg_sectorsize, &start);
 		if (error)
 			errc(EXIT_FAILURE, error, "Invalid start param");
-		start = ALIGNUP(start, alignment);
 	}
 
 	/* No autofill necessary. */
 	if (has_size && has_start && !has_alignment)
 		goto done;
 
+	/* Adjust parameters to offset value for better alignment */
+	s = find_provcfg(pp, "offset");
+	offset = (s == NULL) ? 0:
+	    (off_t)strtoimax(s, NULL, 0) / pp->lg_sectorsize;
+	start = ALIGNUP(start + offset, alignment);
+	if (size + offset > alignment)
+		size = ALIGNDOWN(size + offset, alignment);
+
 	first = (off_t)strtoimax(find_geomcfg(gp, "first"), NULL, 0);
 	last = (off_t)strtoimax(find_geomcfg(gp, "last"), NULL, 0);
 	grade = ~0ULL;
-	a_first = ALIGNUP(first, alignment);
-	last = ALIGNDOWN(last, alignment);
+	a_first = ALIGNUP(first + offset, alignment);
+	last = ALIGNDOWN(last + offset, alignment);
 	while ((pp = find_provider(gp, first)) != NULL) {
 		s = find_provcfg(pp, "start");
 		lba = (off_t)strtoimax(s, NULL, 0);
-		a_lba = ALIGNDOWN(lba, alignment);
+		a_lba = ALIGNDOWN(lba + offset, alignment);
 		if (first < a_lba && a_first < a_lba) {
 			/* Free space [first, lba> */
 			len = a_lba - a_first;
@@ -519,7 +524,7 @@ gpart_autofill(struct gctl_req *req)
 
 		s = find_provcfg(pp, "end");
 		first = (off_t)strtoimax(s, NULL, 0) + 1;
-		a_first = ALIGNUP(first, alignment);
+		a_first = ALIGNUP(first + offset, alignment);
 	}
 	if (a_first <= last) {
 		/* Free space [first-last] */
@@ -543,12 +548,11 @@ gpart_autofill(struct gctl_req *req)
 			}
 		}
 	}
-
 	if (grade == ~0ULL) {
 		geom_deletetree(&mesh);
 		return (ENOSPC);
 	}
-
+	start -= offset;	/* Return back to real offset */
 done:
 	snprintf(ssize, sizeof(ssize), "%jd", (intmax_t)size);
 	gctl_change_param(req, "size", -1, ssize);