From: Karel Zak <kzak@redhat.com>
Date: Mon, 3 Dec 2012 14:32:16 +0000 (+0100)
Subject: fdisk: remove global variable sector_offset
X-Git-Tag: v2.23-rc1~463
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cf3808e468dd0a16506941cde318c8e813a2996e;p=thirdparty%2Futil-linux.git

fdisk: remove global variable sector_offset

 - add cxt->first_lba as replacement to sector_offset
 - add label->reset_alignment() to overwrite the default alignment setting
 - add fdisk_reset_alignment() to setup grain, first LBA offset, etc.

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/fdisks/fdisk.c b/fdisks/fdisk.c
index d9e4f62d06..6ceb7620d4 100644
--- a/fdisks/fdisk.c
+++ b/fdisks/fdisk.c
@@ -62,7 +62,6 @@ int MBRbuffer_changed;
 
 #define sector(s)	((s) & 0x3f)
 #define cylinder(s, c)	((c) | (((s) & 0xc0) << 2))
-#define fdisk_is_disklabel(c, x) fdisk_dev_is_disklabel(c, FDISK_DISKLABEL_ ## x)
 
 /* menu list description */
 
@@ -133,7 +132,6 @@ int	nowarn = 0,			/* no warnings for fdisk -l/-s */
 	partitions = 4;			/* maximum partition + 1 */
 
 unsigned int	user_cylinders, user_heads, user_sectors;
-sector_t sector_offset = 1;
 unsigned int units_per_sector = 1, display_in_cyl_units = 0;
 
 static void __attribute__ ((__noreturn__)) usage(FILE *out)
@@ -322,8 +320,8 @@ sector_t align_lba(struct fdisk_context *cxt, sector_t lba, int direction)
 	else {
 		sector_t sects_in_phy = cxt->grain / cxt->sector_size;
 
-		if (lba < sector_offset)
-			res = sector_offset;
+		if (lba < cxt->first_lba)
+			res = cxt->first_lba;
 
 		else if (direction == ALIGN_UP)
 			res = ((lba + sects_in_phy) / sects_in_phy) * sects_in_phy;
@@ -428,56 +426,6 @@ void warn_alignment(struct fdisk_context *cxt)
 
 }
 
-/*
- * Sets LBA of the first partition
- */
-void
-update_sector_offset(struct fdisk_context *cxt)
-{
-	cxt->grain = cxt->io_size;
-
-	if (dos_compatible_flag)
-		sector_offset = cxt->geom.sectors;	/* usually 63 sectors */
-	else {
-		/*
-		 * Align the begin of partitions to:
-		 *
-		 * a) topology
-		 *  a2) alignment offset
-		 *  a1) or physical sector (minimal_io_size, aka "grain")
-		 *
-		 * b) or default to 1MiB (2048 sectrors, Windows Vista default)
-		 *
-		 * c) or for very small devices use 1 phy.sector
-		 */
-		sector_t x = 0;
-
-		if (fdisk_dev_has_topology(cxt)) {
-			if (cxt->alignment_offset)
-				x = cxt->alignment_offset;
-			else if (cxt->io_size > 2048 * 512)
-				x = cxt->io_size;
-		}
-		/* default to 1MiB */
-		if (!x)
-			x = 2048 * 512;
-
-		sector_offset = x / cxt->sector_size;
-
-		/* don't use huge offset on small devices */
-		if (cxt->total_sectors <= sector_offset * 4)
-			sector_offset = cxt->phy_sector_size / cxt->sector_size;
-
-		/* use 1MiB grain always when possible */
-		if (cxt->grain < 2048 * 512)
-			cxt->grain = 2048 * 512;
-
-		/* don't use huge grain on small devices */
-		if (cxt->total_sectors <= (cxt->grain * 4 / cxt->sector_size))
-			cxt->grain = cxt->phy_sector_size;
-	}
-}
-
 static int is_partition_table_changed(void)
 {
 	int i;
@@ -825,7 +773,7 @@ toggle_dos_compatibility_flag(struct fdisk_context *cxt) {
 	else
 		printf(_("DOS Compatibility flag is not set\n"));
 
-	update_sector_offset(cxt);
+	fdisk_reset_alignment(cxt);
 }
 
 static void delete_partition(struct fdisk_context *cxt, int partnum)
@@ -1465,9 +1413,9 @@ expert_command_prompt(struct fdisk_context *cxt)
 				move_begin(cxt, get_partition(cxt, 0, partitions));
 			break;
 		case 'c':
-			user_cylinders = cxt->geom.cylinders =
-				read_int(cxt, 1, cxt->geom.cylinders, 1048576, 0,
+			user_cylinders = read_int(cxt, 1, cxt->geom.cylinders, 1048576, 0,
 					 _("Number of cylinders"));
+			fdisk_context_set_user_geometry(cxt, user_cylinders, user_heads, user_sectors);
 			if (fdisk_is_disklabel(cxt, SUN))
 				sun_set_ncyl(cxt, cxt->geom.cylinders);
 			break;
@@ -1491,8 +1439,9 @@ expert_command_prompt(struct fdisk_context *cxt)
 			fdisk_create_disklabel(cxt, "sgi");
 			break;
 		case 'h':
-			user_heads = cxt->geom.heads = read_int(cxt, 1, cxt->geom.heads, 256, 0,
+			user_heads = read_int(cxt, 1, cxt->geom.heads, 256, 0,
 					 _("Number of heads"));
+			fdisk_context_set_user_geometry(cxt, user_cylinders, user_heads, user_sectors);
 			update_units(cxt);
 			break;
 		case 'i':
@@ -1516,13 +1465,13 @@ expert_command_prompt(struct fdisk_context *cxt)
 		case 'r':
 			return;
 		case 's':
-			user_sectors = cxt->geom.sectors = read_int(cxt, 1, cxt->geom.sectors, 63, 0,
+			user_sectors = read_int(cxt, 1, cxt->geom.sectors, 63, 0,
 					   _("Number of sectors"));
 			if (dos_compatible_flag)
 				fprintf(stderr, _("Warning: setting "
 					"sector offset for DOS "
 					"compatibility\n"));
-			update_sector_offset(cxt);
+			fdisk_context_set_user_geometry(cxt, user_cylinders, user_heads, user_sectors);
 			update_units(cxt);
 			break;
 		case 'v':
@@ -1777,7 +1726,6 @@ int main(int argc, char **argv)
 			if (sector_size != 512 && sector_size != 1024 &&
 			    sector_size != 2048 && sector_size != 4096)
 				usage(stderr);
-			sector_offset = 2;
 			break;
 		case 'C':
 			user_cylinders =  strtou32_or_err(optarg, _("invalid cylinders argument"));
diff --git a/fdisks/fdisk.h b/fdisks/fdisk.h
index 39aafe63c0..4433eaef96 100644
--- a/fdisks/fdisk.h
+++ b/fdisks/fdisk.h
@@ -158,7 +158,9 @@ struct fdisk_context {
 
 	enum fdisk_labeltype disklabel;	/* current disklabel */
 
+	/* alignment */
 	unsigned long grain;		/* alignment unit */
+	sector_t first_lba;		/* recommended begin of the first partition */
 
 	/* geometry */
 	sector_t total_sectors; /* in logical sectors */
@@ -168,6 +170,8 @@ struct fdisk_context {
 	const struct fdisk_label *label;
 };
 
+#define fdisk_is_disklabel(c, x) fdisk_dev_is_disklabel(c, FDISK_DISKLABEL_ ## x)
+
 /*
  * Label specific operations
  */
@@ -194,6 +198,8 @@ struct fdisk_label {
 	struct fdisk_parttype *(*part_get_type)(struct fdisk_context *cxt, int partnum);
 	/* set partition type */
 	int (*part_set_type)(struct fdisk_context *cxt, int partnum, struct fdisk_parttype *t);
+	/* refresh alignment setting */
+	int (*reset_alignment)(struct fdisk_context *cxt);
 };
 
 /*
@@ -223,6 +229,7 @@ extern int fdisk_add_partition(struct fdisk_context *cxt, int partnum, struct fd
 extern int fdisk_write_disklabel(struct fdisk_context *cxt);
 extern int fdisk_verify_disklabel(struct fdisk_context *cxt);
 extern int fdisk_create_disklabel(struct fdisk_context *cxt, const char *name);
+extern int fdisk_reset_alignment(struct fdisk_context *cxt);
 extern struct fdisk_parttype *fdisk_get_partition_type(struct fdisk_context *cxt, int partnum);
 extern int fdisk_set_partition_type(struct fdisk_context *cxt, int partnum,
 			     struct fdisk_parttype *t);
@@ -237,6 +244,9 @@ extern struct fdisk_parttype *fdisk_parse_parttype(struct fdisk_context *cxt, co
 extern struct fdisk_parttype *fdisk_new_unknown_parttype(unsigned int type, const char *typestr);
 extern void fdisk_free_parttype(struct fdisk_parttype *type);
 
+extern sector_t fdisk_topology_get_first_lba(struct fdisk_context *cxt);
+extern unsigned long fdisk_topology_get_grain(struct fdisk_context *cxt);
+
 /* prototypes for fdisk.c */
 extern char *line_ptr;
 extern int partitions;
@@ -276,7 +286,6 @@ extern unsigned int read_int_with_suffix(struct fdisk_context *cxt,
 				  unsigned int base, char *mesg, int *is_suffix_used);
 extern sector_t align_lba(struct fdisk_context *cxt, sector_t lba, int direction);
 extern int get_partition_dflt(struct fdisk_context *cxt, int warn, int max, int dflt);
-extern void update_sector_offset(struct fdisk_context *cxt);
 
 #define PLURAL	0
 #define SINGULAR 1
diff --git a/fdisks/fdiskdoslabel.c b/fdisks/fdiskdoslabel.c
index bc8e550221..b310acf895 100644
--- a/fdisks/fdiskdoslabel.c
+++ b/fdisks/fdiskdoslabel.c
@@ -26,7 +26,7 @@ static struct fdisk_parttype dos_parttypes[] = {
 		s |= (sector >> 2) & 0xc0;				\
 	}
 
-#define alignment_required	(cxt->grain != cxt->sector_size)
+#define alignment_required(_x)	((_x)->grain != (_x)->sector_size)
 
 struct pte ptes[MAXIMUM_PARTS];
 sector_t extended_offset;
@@ -367,8 +367,24 @@ static void get_partition_table_geometry(struct fdisk_context *cxt,
 		*ph = hh;
 		*ps = ss;
 	}
+
+	DBG(CONTEXT, dbgprint("DOS PT geometry: heads=%u, sectors=%u", *ph, *ps));
 }
 
+static int dos_reset_alignment(struct fdisk_context *cxt)
+{
+	/* overwrite necessary stuff by DOS deprecated stuff */
+	if (dos_compatible_flag) {
+		if (cxt->geom.sectors)
+			cxt->first_lba = cxt->geom.sectors;	/* usually 63 */
+
+		cxt->grain = cxt->sector_size;			/* usually 512 */
+	}
+	/* units_per_sector has impact to deprecated DOS stuff */
+	update_units(cxt);
+
+	return 0;
+}
 
 static int dos_probe_label(struct fdisk_context *cxt)
 {
@@ -459,7 +475,8 @@ static void set_partition(struct fdisk_context *cxt,
 	ptes[i].changed = 1;
 }
 
-static sector_t get_unused_start(int part_n, sector_t start,
+static sector_t get_unused_start(struct fdisk_context *cxt,
+				 int part_n, sector_t start,
 				 sector_t first[], sector_t last[])
 {
 	int i;
@@ -468,8 +485,8 @@ static sector_t get_unused_start(int part_n, sector_t start,
 		sector_t lastplusoff;
 
 		if (start == ptes[i].offset)
-			start += sector_offset;
-		lastplusoff = last[i] + ((part_n < 4) ? 0 : sector_offset);
+			start += cxt->first_lba;
+		lastplusoff = last[i] + ((part_n < 4) ? 0 : cxt->first_lba);
 		if (start >= first[i] && start <= lastplusoff)
 			start = lastplusoff + 1;
 	}
@@ -510,7 +527,7 @@ static int add_partition(struct fdisk_context *cxt, int n, struct fdisk_parttype
 	}
 	fill_bounds(first, last);
 	if (n < 4) {
-		start = sector_offset;
+		start = cxt->first_lba;
 		if (display_in_cyl_units || !cxt->total_sectors)
 			limit = cxt->geom.heads * cxt->geom.sectors * cxt->geom.cylinders - 1;
 		else
@@ -525,7 +542,7 @@ static int add_partition(struct fdisk_context *cxt, int n, struct fdisk_parttype
 				get_nr_sects(q) - 1;
 		}
 	} else {
-		start = extended_offset + sector_offset;
+		start = extended_offset + cxt->first_lba;
 		limit = get_start_sect(q) + get_nr_sects(q) - 1;
 	}
 	if (display_in_cyl_units)
@@ -537,12 +554,12 @@ static int add_partition(struct fdisk_context *cxt, int n, struct fdisk_parttype
 		sector_t dflt, aligned;
 
 		temp = start;
-		dflt = start = get_unused_start(n, start, first, last);
+		dflt = start = get_unused_start(cxt, n, start, first, last);
 
 		/* the default sector should be aligned and unused */
 		do {
 			aligned = align_lba_in_range(cxt, dflt, dflt, limit);
-			dflt = get_unused_start(n, aligned, first, last);
+			dflt = get_unused_start(cxt, n, aligned, first, last);
 		} while (dflt != aligned && dflt > aligned && dflt < limit);
 
 		if (dflt >= limit)
@@ -569,10 +586,10 @@ static int add_partition(struct fdisk_context *cxt, int n, struct fdisk_parttype
 	if (n > 4) {			/* NOT for fifth partition */
 		struct pte *pe = &ptes[n];
 
-		pe->offset = start - sector_offset;
+		pe->offset = start - cxt->first_lba;
 		if (pe->offset == extended_offset) { /* must be corrected */
 			pe->offset++;
-			if (sector_offset == 1)
+			if (cxt->first_lba == 1)
 				start++;
 		}
 	}
@@ -609,7 +626,7 @@ static int add_partition(struct fdisk_context *cxt, int n, struct fdisk_parttype
 				stop = limit;
 		}
 
-		if (is_suffix_used && alignment_required) {
+		if (is_suffix_used && alignment_required(cxt)) {
 			/* the last sector has not been exactly requested (but
 			 * defined by +size{K,M,G} convention), so be smart
 			 * and align the end of the partition. The next
@@ -899,4 +916,5 @@ const struct fdisk_label dos_label =
 	.part_delete = dos_delete_partition,
 	.part_get_type = dos_get_parttype,
 	.part_set_type = dos_set_parttype,
+	.reset_alignment = dos_reset_alignment,
 };
diff --git a/fdisks/fdiskdoslabel.h b/fdisks/fdiskdoslabel.h
index 3b6d64478d..60190ed5b5 100644
--- a/fdisks/fdiskdoslabel.h
+++ b/fdisks/fdiskdoslabel.h
@@ -24,7 +24,7 @@ extern int dos_compatible_flag;
 					      (n) * sizeof(struct partition)))
 
 extern int ext_index; /* the prime extended partition */
-extern sector_t extended_offset, sector_offset;
+extern sector_t extended_offset;
 
 /* A valid partition table sector ends in 0x55 0xaa */
 static inline unsigned int part_table_flag(unsigned char *b)
diff --git a/fdisks/utils.c b/fdisks/utils.c
index da48392ed7..311304351d 100644
--- a/fdisks/utils.c
+++ b/fdisks/utils.c
@@ -198,7 +198,7 @@ int fdisk_context_force_sector_size(struct fdisk_context *cxt, sector_t s)
 	cxt->phy_sector_size = cxt->sector_size = s;
 	cxt->min_io_size = cxt->io_size = s;
 
-	update_sector_offset(cxt);
+	fdisk_reset_alignment(cxt);
 	return 0;
 }
 
@@ -236,7 +236,7 @@ int fdisk_context_set_user_geometry(struct fdisk_context *cxt,
 	else
 		recount_geometry(cxt);
 
-	update_sector_offset(cxt);
+	fdisk_reset_alignment(cxt);
 	return 0;
 }
 
@@ -316,6 +316,7 @@ static int __discover_topology(struct fdisk_context *cxt)
 	return 0;
 }
 
+
 /**
  * fdisk_zeroize_firstsector:
  * @cxt: fdisk context
@@ -368,6 +369,112 @@ int fdisk_dev_has_topology(struct fdisk_context *cxt)
 	return 0;
 }
 
+/*
+ * The LBA of the first partition is based on the device geometry and topology.
+ * This offset is generic (and recommended) for all labels.
+ *
+ * Returns: 0 on error or number of logical sectors.
+ */
+sector_t fdisk_topology_get_first_lba(struct fdisk_context *cxt)
+{
+	sector_t x = 0, res;
+
+	if (!cxt)
+		return 0;
+
+	if (!cxt->io_size)
+		__discover_topology(cxt);
+
+	/*
+	 * Align the begin of partitions to:
+	 *
+	 * a) topology
+	 *  a2) alignment offset
+	 *  a1) or physical sector (minimal_io_size, aka "grain")
+	 *
+	 * b) or default to 1MiB (2048 sectrors, Windows Vista default)
+	 *
+	 * c) or for very small devices use 1 phy.sector
+	 */
+	if (fdisk_dev_has_topology(cxt)) {
+		if (cxt->alignment_offset)
+			x = cxt->alignment_offset;
+		else if (cxt->io_size > 2048 * 512)
+			x = cxt->io_size;
+	}
+	/* default to 1MiB */
+	if (!x)
+		x = 2048 * 512;
+
+	res = x / cxt->sector_size;
+
+	/* don't use huge offset on small devices */
+	if (cxt->total_sectors <= res * 4)
+		res = cxt->phy_sector_size / cxt->sector_size;
+
+	return res;
+}
+
+/*
+ * The LBA of the first partition is based on the device geometry and topology.
+ * This offset is generic generic (and recommended) for all labels.
+ *
+ * Returns: 0 on error or number of bytes.
+ */
+unsigned long fdisk_topology_get_grain(struct fdisk_context *cxt)
+{
+	unsigned long res;
+
+	if (!cxt)
+		return 0;
+
+	if (!cxt->io_size)
+		__discover_topology(cxt);
+
+	res = cxt->io_size;
+
+	/* use 1MiB grain always when possible */
+	if (res < 2048 * 512)
+		res = 2048 * 512;
+
+	/* don't use huge grain on small devices */
+	if (cxt->total_sectors <= (res * 4 / cxt->sector_size))
+		res = cxt->phy_sector_size;
+
+	return res;
+}
+
+/**
+ * fdisk_reset_alignment:
+ * @cxt: fdisk context
+ *
+ * Resets alignment setting to the default or label specific values.
+ *
+ * Returns: 0 on success, < 0 in case of error.
+ */
+int fdisk_reset_alignment(struct fdisk_context *cxt)
+{
+	int rc = 0;
+
+	if (!cxt)
+		return -EINVAL;
+
+	/* default */
+	cxt->grain = fdisk_topology_get_grain(cxt);
+	cxt->first_lba = fdisk_topology_get_first_lba(cxt);
+
+	/* overwrite default by label stuff */
+	if (cxt->label && cxt->label->reset_alignment)
+		rc = cxt->label->reset_alignment(cxt);
+
+	DBG(LABEL, dbgprint("%s alignment reseted to: "
+			    "first LBA=%ju, grain=%lu [rc=%d]",
+			    cxt->label ? cxt->label->name : NULL,
+			    (uintmax_t) cxt->first_lba,
+			    cxt->grain,	rc));
+	return rc;
+}
+
 /**
  * fdisk_dev_has_disklabel:
  * @cxt: fdisk context
@@ -432,6 +539,8 @@ int fdisk_create_disklabel(struct fdisk_context *cxt, const char *name)
 	if (!cxt->label->create)
 		return -ENOSYS;
 
+	fdisk_reset_alignment(cxt);
+
 	return cxt->label->create(cxt);
 }
 
@@ -505,7 +614,7 @@ struct fdisk_context *fdisk_new_context_from_filename(const char *fname, int rea
 	 * to the context */
 	__probe_labels(cxt);
 
-	update_sector_offset(cxt);
+	fdisk_reset_alignment(cxt);
 
 	DBG(CONTEXT, dbgprint("context %p initialized for %s [%s]",
 			      cxt, fname,