MFC r265318:

  For schemes that do an automatic partition aligning move this code to
  separate function.

MFC r265331:
  Prevent an unexpected shrinking on resizing due to alignment for MBR,
  PC98 and VTOC8 schemes.

MFC r265333:
  Add better error description for case when we are doing resize and
  scheme-specific method returns EBUSY.

MFC r265539:
  It is safe to allow shrinking, when aligned size is bigger than current.

5 files changed, 117 insertions, 84 deletions

diff --git a/sys/geom/part/g_part.c b/sys/geom/part/g_part.c
index d556f66..51b20b0 100644
--- a/sys/geom/part/g_part.c
+++ b/sys/geom/part/g_part.c
@@ -1314,7 +1314,9 @@ g_part_ctl_resize(struct gctl_req *req, struct g_part_parms *gpp)
 
 	error = G_PART_RESIZE(table, entry, gpp);
 	if (error) {
-		gctl_error(req, "%d", error);
+		gctl_error(req, "%d%s", error, error != EBUSY ? "":
+		    " resizing will lead to unexpected shrinking"
+		    " due to alignment");
 		return (error);
 	}
 
diff --git a/sys/geom/part/g_part_ebr.c b/sys/geom/part/g_part_ebr.c
index 03b9aac..7a61a68 100644
--- a/sys/geom/part/g_part_ebr.c
+++ b/sys/geom/part/g_part_ebr.c
@@ -217,47 +217,54 @@ ebr_set_chs(struct g_part_table *table, uint32_t lba, u_char *cylp, u_char *hdp,
 }
 
 static int
+ebr_align(struct g_part_table *basetable, uint32_t *start, uint32_t *size)
+{
+	uint32_t sectors;
+
+	sectors = basetable->gpt_sectors;
+	if (*size < 2 * sectors)
+		return (EINVAL);
+	if (*start % sectors) {
+		*size += (*start % sectors) - sectors;
+		*start -= (*start % sectors) - sectors;
+	}
+	if (*size % sectors)
+		*size -= (*size % sectors);
+	if (*size < 2 * sectors)
+		return (EINVAL);
+	return (0);
+}
+
+
+static int
 g_part_ebr_add(struct g_part_table *basetable, struct g_part_entry *baseentry,
     struct g_part_parms *gpp)
 {
-	struct g_geom *gp;
 	struct g_provider *pp;
 	struct g_part_ebr_entry *entry;
-	uint32_t start, size, sectors;
+	uint32_t start, size;
 
 	if (gpp->gpp_parms & G_PART_PARM_LABEL)
 		return (EINVAL);
 
-	gp = basetable->gpt_gp;
-	pp = LIST_FIRST(&gp->consumer)->provider;
-	sectors = basetable->gpt_sectors;
-
+	pp = LIST_FIRST(&basetable->gpt_gp->consumer)->provider;
 	entry = (struct g_part_ebr_entry *)baseentry;
-
 	start = gpp->gpp_start;
 	size = gpp->gpp_size;
-	if (size < 2 * sectors)
-		return (EINVAL);
-	if (start % sectors) {
-		size = size - sectors + (start % sectors);
-		start = start - (start % sectors) + sectors;
-	}
-	if (size % sectors)
-		size = size - (size % sectors);
-	if (size < 2 * sectors)
+	if (ebr_align(basetable, &start, &size) != 0)
 		return (EINVAL);
-
 	if (baseentry->gpe_deleted)
 		bzero(&entry->ent, sizeof(entry->ent));
 
 	KASSERT(baseentry->gpe_start <= start, ("%s", __func__));
 	KASSERT(baseentry->gpe_end >= start + size - 1, ("%s", __func__));
-	baseentry->gpe_index = (start / sectors) + 1;
-	baseentry->gpe_offset = (off_t)(start + sectors) * pp->sectorsize;
+	baseentry->gpe_index = (start / basetable->gpt_sectors) + 1;
+	baseentry->gpe_offset =
+	    (off_t)(start + basetable->gpt_sectors) * pp->sectorsize;
 	baseentry->gpe_start = start;
 	baseentry->gpe_end = start + size - 1;
-	entry->ent.dp_start = sectors;
-	entry->ent.dp_size = size - sectors;
+	entry->ent.dp_start = basetable->gpt_sectors;
+	entry->ent.dp_size = size - basetable->gpt_sectors;
 	ebr_set_chs(basetable, entry->ent.dp_start, &entry->ent.dp_scyl,
 	    &entry->ent.dp_shd, &entry->ent.dp_ssect);
 	ebr_set_chs(basetable, baseentry->gpe_end, &entry->ent.dp_ecyl,
diff --git a/sys/geom/part/g_part_mbr.c b/sys/geom/part/g_part_mbr.c
index 459aee6..0782e01 100644
--- a/sys/geom/part/g_part_mbr.c
+++ b/sys/geom/part/g_part_mbr.c
@@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/sysctl.h>
 #include <geom/geom.h>
+#include <geom/geom_int.h>
 #include <geom/part/g_part.h>
 
 #include "g_part_if.h"
@@ -195,34 +196,39 @@ mbr_set_chs(struct g_part_table *table, uint32_t lba, u_char *cylp, u_char *hdp,
 }
 
 static int
+mbr_align(struct g_part_table *basetable, uint32_t *start, uint32_t *size)
+{
+	uint32_t sectors;
+
+	sectors = basetable->gpt_sectors;
+	if (*size < sectors)
+		return (EINVAL);
+	if (start != NULL && (*start % sectors)) {
+		*size += (*start % sectors) - sectors;
+		*start -= (*start % sectors) - sectors;
+	}
+	if (*size % sectors)
+		*size -= (*size % sectors);
+	if (*size < sectors)
+		return (EINVAL);
+	return (0);
+}
+
+static int
 g_part_mbr_add(struct g_part_table *basetable, struct g_part_entry *baseentry,
     struct g_part_parms *gpp)
 {
 	struct g_part_mbr_entry *entry;
-	struct g_part_mbr_table *table;
-	uint32_t start, size, sectors;
+	uint32_t start, size;
 
 	if (gpp->gpp_parms & G_PART_PARM_LABEL)
 		return (EINVAL);
 
-	sectors = basetable->gpt_sectors;
-
 	entry = (struct g_part_mbr_entry *)baseentry;
-	table = (struct g_part_mbr_table *)basetable;
-
 	start = gpp->gpp_start;
 	size = gpp->gpp_size;
-	if (size < sectors)
+	if (mbr_align(basetable, &start, &size) != 0)
 		return (EINVAL);
-	if (start % sectors) {
-		size = size - sectors + (start % sectors);
-		start = start - (start % sectors) + sectors;
-	}
-	if (size % sectors)
-		size = size - (size % sectors);
-	if (size < sectors)
-		return (EINVAL);
-
 	if (baseentry->gpe_deleted)
 		bzero(&entry->ent, sizeof(entry->ent));
 
@@ -336,18 +342,17 @@ g_part_mbr_resize(struct g_part_table *basetable,
     struct g_part_entry *baseentry, struct g_part_parms *gpp)
 {
 	struct g_part_mbr_entry *entry;
-	uint32_t size, sectors;
+	struct g_provider *pp;
+	uint32_t size;
 
-	sectors = basetable->gpt_sectors;
 	size = gpp->gpp_size;
-
-	if (size < sectors)
+	if (mbr_align(basetable, NULL, &size) != 0)
 		return (EINVAL);
-	if (size % sectors)
-		size = size - (size % sectors);
-	if (size < sectors)
-		return (EINVAL);
-
+	/* XXX: prevent unexpected shrinking. */
+	pp = baseentry->gpe_pp;
+	if ((g_debugflags & 0x10) == 0 && size < gpp->gpp_size &&
+	    pp->mediasize / pp->sectorsize > size)
+		return (EBUSY);
 	entry = (struct g_part_mbr_entry *)baseentry;
 	baseentry->gpe_end = baseentry->gpe_start + size - 1;
 	entry->ent.dp_size = size;
diff --git a/sys/geom/part/g_part_pc98.c b/sys/geom/part/g_part_pc98.c
index d18d5cf..4a15215 100644
--- a/sys/geom/part/g_part_pc98.c
+++ b/sys/geom/part/g_part_pc98.c
@@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/sysctl.h>
 #include <geom/geom.h>
+#include <geom/geom_int.h>
 #include <geom/part/g_part.h>
 
 #include "g_part_if.h"
@@ -175,32 +176,37 @@ pc98_set_chs(struct g_part_table *table, uint32_t lba, u_short *cylp,
 }
 
 static int
+pc98_align(struct g_part_table *basetable, uint32_t *start, uint32_t *size)
+{
+	uint32_t cyl;
+
+	cyl = basetable->gpt_heads * basetable->gpt_sectors;
+	if (*size < cyl)
+		return (EINVAL);
+	if (start != NULL && (*start % cyl)) {
+		*size += (*start % cyl) - cyl;
+		*start -= (*start % cyl) - cyl;
+	}
+	if (*size % cyl)
+		*size -= (*size % cyl);
+	if (*size < cyl)
+		return (EINVAL);
+	return (0);
+}
+
+static int
 g_part_pc98_add(struct g_part_table *basetable, struct g_part_entry *baseentry,
     struct g_part_parms *gpp)
 {
 	struct g_part_pc98_entry *entry;
-	struct g_part_pc98_table *table;
-	uint32_t cyl, start, size;
+	uint32_t start, size;
 	int error;
 
-	cyl = basetable->gpt_heads * basetable->gpt_sectors;
-
 	entry = (struct g_part_pc98_entry *)baseentry;
-	table = (struct g_part_pc98_table *)basetable;
-
 	start = gpp->gpp_start;
 	size = gpp->gpp_size;
-	if (size < cyl)
+	if (pc98_align(basetable, &start, &size) != 0)
 		return (EINVAL);
-	if (start % cyl) {
-		size = size - cyl + (start % cyl);
-		start = start - (start % cyl) + cyl;
-	}
-	if (size % cyl)
-		size = size - (size % cyl);
-	if (size < cyl)
-		return (EINVAL);
-
 	if (baseentry->gpe_deleted)
 		bzero(&entry->ent, sizeof(entry->ent));
 	else
@@ -343,18 +349,17 @@ g_part_pc98_resize(struct g_part_table *basetable,
     struct g_part_entry *baseentry, struct g_part_parms *gpp)
 {
 	struct g_part_pc98_entry *entry;
-	uint32_t size, cyl;
+	struct g_provider *pp;
+	uint32_t size;
 
-	cyl = basetable->gpt_heads * basetable->gpt_sectors;
 	size = gpp->gpp_size;
-
-	if (size < cyl)
+	if (pc98_align(basetable, NULL, &size) != 0)
 		return (EINVAL);
-	if (size % cyl)
-		size = size - (size % cyl);
-	if (size < cyl)
-		return (EINVAL);
-
+	/* XXX: prevent unexpected shrinking. */
+	pp = baseentry->gpe_pp;
+	if ((g_debugflags & 0x10) == 0 && size < gpp->gpp_size &&
+	    pp->mediasize / pp->sectorsize > size)
+		return (EBUSY);
 	entry = (struct g_part_pc98_entry *)baseentry;
 	baseentry->gpe_end = baseentry->gpe_start + size - 1;
 	pc98_set_chs(basetable, baseentry->gpe_end, &entry->ent.dp_ecyl,
diff --git a/sys/geom/part/g_part_vtoc8.c b/sys/geom/part/g_part_vtoc8.c
index e993eff..e22a590 100644
--- a/sys/geom/part/g_part_vtoc8.c
+++ b/sys/geom/part/g_part_vtoc8.c
@@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/sysctl.h>
 #include <sys/vtoc.h>
 #include <geom/geom.h>
+#include <geom/geom_int.h>
 #include <geom/part/g_part.h>
 
 #include "g_part_if.h"
@@ -143,6 +144,23 @@ vtoc8_parse_type(const char *type, uint16_t *tag)
 }
 
 static int
+vtoc8_align(struct g_part_vtoc8_table *table, uint64_t *start, uint64_t *size)
+{
+
+	if (*size < table->secpercyl)
+		return (EINVAL);
+	if (start != NULL && (*start % table->secpercyl)) {
+		*size += (*start % table->secpercyl) - table->secpercyl;
+		*start -= (*start % table->secpercyl) - table->secpercyl;
+	}
+	if (*size % table->secpercyl)
+		*size -= (*size % table->secpercyl);
+	if (*size < table->secpercyl)
+		return (EINVAL);
+	return (0);
+}
+
+static int
 g_part_vtoc8_add(struct g_part_table *basetable, struct g_part_entry *entry,
     struct g_part_parms *gpp)
 {
@@ -160,16 +178,9 @@ g_part_vtoc8_add(struct g_part_table *basetable, struct g_part_entry *entry,
 
 	table = (struct g_part_vtoc8_table *)basetable;
 	index = entry->gpe_index - 1;
-
 	start = gpp->gpp_start;
 	size = gpp->gpp_size;
-	if (start % table->secpercyl) {
-		size = size - table->secpercyl + (start % table->secpercyl);
-		start = start - (start % table->secpercyl) + table->secpercyl;
-	}
-	if (size % table->secpercyl)
-		size = size - (size % table->secpercyl);
-	if (size < table->secpercyl)
+	if (vtoc8_align(table, &start, &size) != 0)
 		return (EINVAL);
 
 	KASSERT(entry->gpe_start <= start, (__func__));
@@ -310,15 +321,18 @@ g_part_vtoc8_resize(struct g_part_table *basetable,
     struct g_part_entry *entry, struct g_part_parms *gpp)
 {
 	struct g_part_vtoc8_table *table;
+	struct g_provider *pp;
 	uint64_t size;
 
 	table = (struct g_part_vtoc8_table *)basetable;
 	size = gpp->gpp_size;
-	if (size % table->secpercyl)
-		size = size - (size % table->secpercyl);
-	if (size < table->secpercyl)
+	if (vtoc8_align(table, NULL, &size) != 0)
 		return (EINVAL);
-
+	/* XXX: prevent unexpected shrinking. */
+	pp = entry->gpe_pp;
+	if ((g_debugflags & 0x10) == 0 && size < gpp->gpp_size &&
+	    pp->mediasize / pp->sectorsize > size)
+		return (EBUSY);
 	entry->gpe_end = entry->gpe_start + size - 1;
 	be32enc(&table->vtoc.map[entry->gpe_index - 1].nblks, size);