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fdisk: offer aligned first sector 

Typical "new partition" dialog looks like:

     Partition number (1-4): 1
     First sector (4-818687, default 4):
                             ^^^^^^^^^

The range (e.g. 4-818687) depends on fdisk mode (DOS/non-DOS), but the
default value should be always aligned.

For example RAID5 device in the DOS mode:

   Disk /dev/md0: 419 MB, 419168256 bytes
   2 heads, 4 sectors/track, 102336 cylinders, total 818688 sectors
   Units = sectors of 1 * 512 = 512 bytes
   Sector size (logical/physical): 512 bytes / 65536 bytes
   Disk identifier: 0x081479c3

   ....

   Command (m for help): n
   Command action
      e   extended
      p   primary partition (1-4)
   p
   Partition number (1-4): 1
   First sector (4-818687, default 128):    <---- !!!
   Using default value 128
   Last sector, +sectors or +size{K,M,G} (128-818687, default 818687): +10M

   Command (m for help): p

   ....

       Device Boot      Start         End      Blocks   Id  System
   /dev/md0p1             128       20607       10240   83  Linux

For non-DOS mode the range will be:

   First sector (128-818687, default 128):

Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2009-11-04 15:14:04 +01:00
parent b7e76f8ef1
commit 81dc64f8c0
1 changed files with 35 additions and 10 deletions
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45
fdisk/fdisk.c
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@ -2210,6 +2210,27 @@ verify(void) {
n_sectors - total, sector_size);
}
static unsigned long long
get_unused_start(int part_n,
unsigned long long start,
unsigned long long first[],
unsigned long long last[])
{
int i;
for (i = 0; i < partitions; i++) {
unsigned long long lastplusoff;
if (start == ptes[i].offset)
start += sector_offset;
lastplusoff = last[i] + ((part_n < 4) ? 0 : sector_offset);
if (start >= first[i] && start <= lastplusoff)
start = lastplusoff + 1;
}
return start;
}
static void
add_partition(int n, int sys) {
char mesg[256]; /* 48 does not suffice in Japanese */
@ -2250,16 +2271,20 @@ add_partition(int n, int sys) {
snprintf(mesg, sizeof(mesg), _("First %s"), str_units(SINGULAR));
do {
temp = start;
for (i = 0; i < partitions; i++) {
unsigned long long lastplusoff;
unsigned long long dflt, dflt_tmp;
if (start == ptes[i].offset)
start += sector_offset;
lastplusoff = last[i] + ((n<4) ? 0 : sector_offset);
if (start >= first[i] && start <= lastplusoff)
start = lastplusoff + 1;
}
temp = start;
dflt = start = get_unused_start(n, start, first, last);
/* the default sector should be aligned and unused */
do {
dflt_tmp = align_lba_in_range(dflt, start, limit);
dflt = get_unused_start(n, dflt_tmp, first, last);
} while (dflt != dflt_tmp && dflt > dflt_tmp && dflt < limit);
if (dflt >= limit)
dflt = start;
if (start > limit)
break;
if (start >= temp+units_per_sector && read) {
@ -2270,7 +2295,7 @@ add_partition(int n, int sys) {
if (!read && start == temp) {
unsigned long long i = start;
start = read_int(cround(i), cround(i), cround(limit),
start = read_int(cround(i), cround(dflt), cround(limit),
0, mesg);
if (display_in_cyl_units) {
start = (start - 1) * units_per_sector;