libfdisk: (dos) allow to maximize partition

The struct fdisk_partition has special flag "end_follow_default" to
make the partition large as much as possible. This patch makes this
flag usable for fdisk_set_partition() function.

Command line example (enlarge the first partition):

	# echo ',+' | ./sfdisk -N1 /dev/sdb
	...
	Disk /dev/sdb: 100 MiB, 104857600 bytes, 204800 sectors
	...
	Old situation:
	Device     Boot Start   End Sectors Size Id Type
	/dev/sdb1        2048 22527   20480  10M 83 Linux
			      ^^^^^
	New situation:
	Device     Boot Start    End Sectors Size Id Type
	/dev/sdb1        2048 204799  202752  99M 83 Linux
			      ^^^^^^

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

diff --git a/disk-utils/sfdisk.c b/disk-utils/sfdisk.c
index f48d1c743d3d065c38db24b1e1f654a22a83a86a..b22ee40ae7f23676eadea90b9f26207aeb1d901d 100644 (file)
--- a/disk-utils/sfdisk.c
+++ b/disk-utils/sfdisk.c
@@ -936,6 +936,8 @@ static void command_fdisk_help(void)
        fputs(_("   abort    exit sfdisk shell\n"), stdout);
        fputs(_("   print    print partition table.\n"), stdout);
        fputs(_("   help     this help.\n"), stdout);
+       fputc('\n', stdout);
+       fputs(_("   CTRL-D   the same like 'quit' command\n"), stdout);
 
        fputc('\n', stdout);
        color_scheme_enable("help-title", UL_COLOR_BOLD);

diff --git a/libfdisk/src/dos.c b/libfdisk/src/dos.c
index 1972ce252914c4176308cedb3d212618579fd35e..54af66cf91f94c056a57b7872828bb17c4d1eea8 100644 (file)
--- a/libfdisk/src/dos.c
+++ b/libfdisk/src/dos.c
@@ -949,6 +949,57 @@ static int get_start_from_user(    struct fdisk_context *cxt,
        return 0;
 }
 
+static sector_t get_possible_last(struct fdisk_context *cxt, size_t n)
+{
+       sector_t limit;
+
+       if (n >= 4) {
+               /* logical partitions */
+               struct fdisk_dos_label *l = self_label(cxt);
+               struct pte *ext_pe = l->ext_offset ? self_pte(cxt, l->ext_index) : NULL;
+
+               if (!ext_pe)
+                       return 0;
+               limit = get_abs_partition_end(ext_pe);
+       } else {
+               /* primary partitions */
+               if (fdisk_use_cylinders(cxt) || !cxt->total_sectors)
+                       limit = cxt->geom.heads * cxt->geom.sectors * cxt->geom.cylinders - 1;
+               else
+                       limit = cxt->total_sectors - 1;
+
+               if (limit > UINT_MAX)
+                       limit = UINT_MAX;
+       }
+
+       DBG(LABEL, ul_debug("DOS: last possible sector for #%zu is %ju",
+                               n, (uintmax_t) limit));
+       return limit;
+}
+
+/* returns last free sector for area addressed by @start, the first[] and
+ * last[] are fill_bounds() results */
+static sector_t get_unused_last(struct fdisk_context *cxt, size_t n,
+                               sector_t start,
+                               sector_t first[], sector_t last[])
+{
+       size_t i;
+       sector_t limit = get_possible_last(cxt, n);
+
+       for (i = 0; i < cxt->label->nparts_max; i++) {
+               struct pte *pe = self_pte(cxt, i);
+
+               if (start < pe->offset && limit >= pe->offset)
+                       limit = pe->offset - 1;
+               if (start < first[i] && limit >= first[i])
+                       limit = first[i] - 1;
+       }
+
+       DBG(LABEL, ul_debug("DOS: unused sector for #%zu is %ju",
+                               n, (uintmax_t) limit));
+       return limit;
+}
+
 static int add_partition(struct fdisk_context *cxt, size_t n,
                         struct fdisk_partition *pa)
 {
@@ -973,6 +1024,8 @@ static int add_partition(struct fdisk_context *cxt, size_t n,
                return -EINVAL;
        }
        fill_bounds(cxt, first, last);
+       limit = get_possible_last(cxt, n);
+
        if (n < 4) {
                if (cxt->parent && fdisk_is_label(cxt->parent, GPT))
                        start = 1;              /* Bad boy modifies hybrid MBR */
@@ -985,14 +1038,6 @@ static int add_partition(struct fdisk_context *cxt, size_t n,
                        start = cxt->first_lba;
                }
 
-               if (fdisk_use_cylinders(cxt) || !cxt->total_sectors)
-                       limit = cxt->geom.heads * cxt->geom.sectors * cxt->geom.cylinders - 1;
-               else
-                       limit = cxt->total_sectors - 1;
-
-               if (limit > UINT_MAX)
-                       limit = UINT_MAX;
-
                if (l->ext_offset) {
                        assert(ext_pe);
                        first[l->ext_index] = l->ext_offset;
@@ -1000,7 +1045,6 @@ static int add_partition(struct fdisk_context *cxt, size_t n,
                }
        } else {
                assert(ext_pe);
-               limit = get_abs_partition_end(ext_pe);
 
                if (cxt->script && pa && fdisk_partition_has_start(pa)
                    && pa->start >= l->ext_offset
@@ -1008,8 +1052,8 @@ static int add_partition(struct fdisk_context *cxt, size_t n,
                        fdisk_set_first_lba(cxt, 1);
 
                start = l->ext_offset + cxt->first_lba;
-
        }
+
        if (fdisk_use_cylinders(cxt))
                for (i = 0; i < cxt->label->nparts_max; i++) {
                        first[i] = (fdisk_cround(cxt, first[i]) - 1)
@@ -1078,14 +1122,8 @@ static int add_partition(struct fdisk_context *cxt, size_t n,
                }
        }
 
-       for (i = 0; i < cxt->label->nparts_max; i++) {
-               struct pte *pe = self_pte(cxt, i);
+       limit = get_unused_last(cxt, n, start, first, last);
 
-               if (start < pe->offset && limit >= pe->offset)
-                       limit = pe->offset - 1;
-               if (start < first[i] && limit >= first[i])
-                       limit = first[i] - 1;
-       }
        if (start > limit) {
                fdisk_info(cxt, _("No free sectors available."));
                if (n > 4)
@@ -1822,8 +1860,10 @@ static int dos_get_partition(struct fdisk_context *cxt, size_t n,
 static int dos_set_partition(struct fdisk_context *cxt, size_t n,
                             struct fdisk_partition *pa)
 {
+       struct fdisk_dos_label *l;
        struct dos_partition *p;
        struct pte *pe;
+       sector_t start, size;
 
        assert(cxt);
        assert(pa);
@@ -1842,23 +1882,54 @@ static int dos_set_partition(struct fdisk_context *cxt, size_t n,
        if (pa->type && !pa->type->code)
                fdisk_warnx(cxt, _("Type 0 means free space to many systems. "
                                   "Having partitions of type 0 is probably unwise."));
+       l = self_label(cxt);
+       p = self_partition(cxt, n);
+       pe = self_pte(cxt, n);
 
-       p  = self_partition(cxt, n);
+       FDISK_INIT_UNDEF(start);
+       FDISK_INIT_UNDEF(size);
 
-       if (fdisk_partition_has_start(pa) || fdisk_partition_has_size(pa)) {
-               sector_t start, size;
+       if (fdisk_partition_has_start(pa))
+               start = pa->start;
+       if (fdisk_partition_has_size(pa))
+               size = pa->size;
 
-               DBG(LABEL, ul_debug("DOS: resize partition"));
+       if (pa->end_follow_default) {
+               sector_t first[cxt->label->nparts_max],
+                        last[cxt->label->nparts_max],
+                        xlast;
+               struct pte *ext = l->ext_offset ? self_pte(cxt, l->ext_index) : NULL; 
+
+               fill_bounds(cxt, first, last);
+
+               if (ext && l->ext_offset) {
+                       first[l->ext_index] = l->ext_offset;
+                       last[l->ext_index] = get_abs_partition_end(ext);
+               }
+               if (FDISK_IS_UNDEF(start))
+                       start = get_abs_partition_start(pe);
+
+               DBG(LABEL, ul_debug("DOS: #%zu    now %ju +%ju sectors",
+                       n, (uintmax_t) start, (uintmax_t) dos_partition_get_size(p)));
+
+               xlast = get_unused_last(cxt, n, start, first, last);
+               size = xlast ? xlast - start + 1: dos_partition_get_size(p);
 
-               pe = self_pte(cxt, n);
+               DBG(LABEL, ul_debug("DOS: #%zu wanted %ju +%ju sectors",
+                       n, (uintmax_t) start, (uintmax_t) size));
+       }
+
+       if (!FDISK_IS_UNDEF(start) || !FDISK_IS_UNDEF(size)) {
+               DBG(LABEL, ul_debug("DOS: resize partition"));
 
-               start = fdisk_partition_has_start(pa) ? pa->start : get_abs_partition_start(pe);
-               size = fdisk_partition_has_size(pa) ? pa->size : dos_partition_get_size(p);
+               if (FDISK_IS_UNDEF(start))
+                       start = get_abs_partition_start(pe);
+               if (FDISK_IS_UNDEF(size))
+                       size = dos_partition_get_size(p);
 
                set_partition(cxt, n, 0, start, start + size - 1,
                                pa->type  ? pa->type->code : p->sys_ind,
                                pa->boot == 1);
-
        } else {
                DBG(LABEL, ul_debug("DOS: keep size, modify properties"));
                if (pa->type)