From 81745b42a2722f11006c05de87ff90de08cf8cee Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Tue, 28 Jun 2016 11:30:21 +0200
Subject: [PATCH] fdisk: backport DOS logical partitions chain reorder
... from the current upstream.
Addresses: http://bugzilla.redhat.com/show_bug.cgi?id=1304246
Signed-off-by: Karel Zak <kzak@redhat.com>
---
fdisks/fdiskdoslabel.c | 170 +++++++++++++++++++++++++++++++++----------------
include/c.h | 8 +++
2 files changed, 124 insertions(+), 54 deletions(-)
diff --git a/fdisks/fdiskdoslabel.c b/fdisks/fdiskdoslabel.c
index fe04ac7..b7eb35a 100644
--- a/fdisks/fdiskdoslabel.c
+++ b/fdisks/fdiskdoslabel.c
@@ -55,6 +55,22 @@ static int MBRbuffer_changed;
#define cround(c, n) (fdisk_context_use_cylinders(c) ? \
((n) / fdisk_context_get_units_per_sector(c)) + 1 : (n))
+
+static unsigned long long
+get_abs_partition_start(struct pte *pe)
+{
+ return pe->offset + get_start_sect(pe->part_table);
+}
+
+static unsigned long long
+get_abs_partition_end(struct pte *pe)
+{
+ unsigned long long size;
+
+ size = get_nr_sects(pe->part_table);
+ return get_abs_partition_start(pe) + size - (size ? 1 : 0);
+}
+
static void warn_alignment(struct fdisk_context *cxt)
{
if (nowarn)
@@ -1254,67 +1270,113 @@ void dos_list_table_expert(struct fdisk_context *cxt, int extend)
}
}
-/*
- * Fix the chain of logicals.
- * extended_offset is unchanged, the set of sectors used is unchanged
- * The chain is sorted so that sectors increase, and so that
- * starting sectors increase.
- *
- * After this it may still be that cfdisk doesn't like the table.
- * (This is because cfdisk considers expanded parts, from link to
- * end of partition, and these may still overlap.)
- * Now
- * sfdisk /dev/hda > ohda; sfdisk /dev/hda < ohda
- * may help.
- */
+
+static void print_chain_of_logicals(struct fdisk_context *cxt)
+{
+ size_t i;
+
+ fputc('\n', stdout);
+
+ for (i = 4; i < cxt->label->nparts_max; i++) {
+ struct pte *pe = &ptes[i];
+
+ fprintf(stderr, "#%02zu EBR [%10ju], "
+ "data[start=%10ju (%10ju), size=%10ju], "
+ "link[start=%10ju (%10ju), size=%10ju]\n",
+ i, (uintmax_t) pe->offset,
+ /* data */
+ (uintmax_t) get_start_sect(pe->part_table),
+ (uintmax_t) get_abs_partition_start(pe),
+ (uintmax_t) get_nr_sects(pe->part_table),
+ /* link */
+ (uintmax_t) get_start_sect(pe->ext_pointer),
+ (uintmax_t) (extended_offset + get_start_sect(pe->ext_pointer)),
+ (uintmax_t) get_nr_sects(pe->ext_pointer));
+ }
+}
+
+static int cmp_ebr_offsets(const void *a, const void *b)
+{
+ struct pte *ae = (struct pte *) a,
+ *be = (struct pte *) b;
+
+ if (ae->offset == 0 && be->offset == 0)
+ return 0;
+ if (ae->offset == 0)
+ return 1;
+ if (be->offset == 0)
+ return -1;
+
+ return cmp_numbers(ae->offset, be->offset);
+}
+
static void fix_chain_of_logicals(struct fdisk_context *cxt)
{
- size_t j, oj, ojj, sj, sjj;
- struct partition *pj,*pjj,tmp;
-
- /* Stage 1: sort sectors but leave sector of part 4 */
- /* (Its sector is the global extended_offset.) */
- stage1:
- for (j = 5; j < cxt->label->nparts_max - 1; j++) {
- oj = ptes[j].offset;
- ojj = ptes[j+1].offset;
- if (oj > ojj) {
- ptes[j].offset = ojj;
- ptes[j+1].offset = oj;
- pj = ptes[j].part_table;
- set_start_sect(pj, get_start_sect(pj)+oj-ojj);
- pjj = ptes[j+1].part_table;
- set_start_sect(pjj, get_start_sect(pjj)+ojj-oj);
- set_start_sect(ptes[j-1].ext_pointer,
- ojj-extended_offset);
- set_start_sect(ptes[j].ext_pointer,
- oj-extended_offset);
- goto stage1;
+ struct pte *last;
+ size_t i;
+
+ DBG(CONTEXT, print_chain_of_logicals(cxt));
+
+ /* Sort chain by EBR offsets */
+ qsort(&ptes[4], cxt->label->nparts_max - 4, sizeof(struct pte),
+ cmp_ebr_offsets);
+
+again:
+ /* Sort data partitions by start */
+ for (i = 4; i < cxt->label->nparts_max - 1; i++) {
+ struct pte *cur = &ptes[i],
+ *nxt = &ptes[i + 1];
+
+ if (get_abs_partition_start(cur) >
+ get_abs_partition_start(nxt)) {
+
+ struct partition tmp = *cur->part_table;
+ sector_t cur_start = get_abs_partition_start(cur),
+ nxt_start = get_abs_partition_start(nxt);
+
+ /* swap data partitions */
+ *cur->part_table = *nxt->part_table;
+ *nxt->part_table = tmp;
+
+ /* Recount starts according to EBR offsets, the absolute
+ * address still has to be the same! */
+ set_start_sect(cur->part_table, nxt_start - cur->offset);
+ set_start_sect(nxt->part_table, cur_start - nxt->offset);
+
+ cur->changed = 1;
+ nxt->changed = 1;
+ goto again;
}
}
- /* Stage 2: sort starting sectors */
- stage2:
- for (j = 4; j < cxt->label->nparts_max - 1; j++) {
- pj = ptes[j].part_table;
- pjj = ptes[j+1].part_table;
- sj = get_start_sect(pj);
- sjj = get_start_sect(pjj);
- oj = ptes[j].offset;
- ojj = ptes[j+1].offset;
- if (oj+sj > ojj+sjj) {
- tmp = *pj;
- *pj = *pjj;
- *pjj = tmp;
- set_start_sect(pj, ojj+sjj-oj);
- set_start_sect(pjj, oj+sj-ojj);
- goto stage2;
- }
+ /* Update EBR links */
+ for (i = 4; i < cxt->label->nparts_max - 1; i++) {
+ struct pte *cur = &ptes[i],
+ *nxt = &ptes[i + 1];
+
+ sector_t noff = nxt->offset - extended_offset,
+ ooff = get_start_sect(cur->ext_pointer);
+
+ if (noff == ooff)
+ continue;
+
+ DBG(CONTEXT, dbgprint("DOS: fix EBR [%10ju] link %ju -> %ju",
+ (uintmax_t) cur->offset,
+ (uintmax_t) ooff, (uintmax_t) noff));
+
+ set_partition(cxt, i, 1, nxt->offset,
+ get_abs_partition_end(nxt),
+ EXTENDED);
+ }
+
+ /* always terminate the chain ! */
+ last = &ptes[cxt->label->nparts_max - 1];
+ if (last) {
+ clear_partition(last->ext_pointer);
+ last->changed = 1;
}
- /* Probably something was changed */
- for (j = 4; j < cxt->label->nparts_max; j++)
- ptes[j].changed = 1;
+ DBG(CONTEXT, print_chain_of_logicals(cxt));
}
void dos_fix_partition_table_order(struct fdisk_context *cxt)
diff --git a/include/c.h b/include/c.h
index a50e8a5..ef2ea69 100644
--- a/include/c.h
+++ b/include/c.h
@@ -110,6 +110,14 @@
_max1 > _max2 ? _max1 : _max2; })
#endif
+#ifndef cmp_numbers
+# define cmp_numbers(x, y) __extension__ ({ \
+ __typeof__(x) _a = (x); \
+ __typeof__(y) _b = (y); \
+ (void) (&_a == &_b); \
+ _a == _b ? 0 : _a > _b ? 1 : -1; })
+#endif
+
#ifndef offsetof
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif
--
2.7.4