[Parted-maintainers] Bug#292111: installation-reports: FAILURE TO ... [proposed solution]
Sven Luther
Sven Luther <sven.luther@wanadoo.fr>, 292111@bugs.debian.org
Sun, 13 Feb 2005 09:41:32 +0100
tags 292111 + upstream help
thanks
Hello fellow parted developers, i got this bug report, whose complet log is at :
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=292111
And i am really baffled about what is going on here. I am no expert on MBRs,
and i didn't know if it would be possible, or even be legal, to have a
partition table like the one described here.
Gene, i forward this upstream, sorry for the delays in responding, and i hope
that this will be solved soon. I have a feeling that your partition table is
somewhat hosed though, not sure. How did you create it again ?
Friendly,
Sven Luther
On Sun, Feb 13, 2005 at 03:15:42AM -0500, Gene Cooperman wrote:
> Well, I now understand what parted is doing, and why it doesn't work on
> my system. Apparently, the extended partition of my partition table
> has a hole in it, and a physical partion occupies that hole.
> My partition table has:
> 1. /dev/hde1 -- physical partition (ntfs)
> 2. /dev/hde2 -- extended partition with hole in it;
> i.e. it goes from the end of /dev/hde1 to the end of the disk.
> However, there is a region inside the extended partition
> that is not occupied by any logical partition.
> 3. /dev/hde3 -- physical partition (linux-swap);
> This partition is located exactly in the hole that is in
> the middle of the extended partition, /dev/hde2
> 4. /dev/hde5, [hole], /dev/hde6, /dev/hde7, /dev/hde8 -- logical partitions
>
> If this is the case, I suspect that I could use a different partition
> software such as Mandrake's Drake to delete /dev/hde3 and leave it free.
> I could then use parted to recreate a linux-swap partition, but now
> as a logical partition using the free disk space. Does this seem
> like a reasonable plan, or could it be dangerous?
> [ I know, back up my files before I do anything. :-) ]
>
> I include further analysis of what parted does on my system below.
> I also suggest where parted could include a warning that would have
> diagnosed the current situation quickly and painlessly.
>
> ==============================================================
> I interject here to illustrate the point with the results of fdisk:
>
> Command (m for help): p
>
> Disk /dev/hde: 163.9 GB, 163928604672 bytes
> 255 heads, 63 sectors/track, 19929 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
> Device Boot Start End Blocks Id System
> /dev/hde1 * 1 7654 61480723+ 7 HPFS/NTFS
> /dev/hde2 7655 19930 98605773 5 Extended
> /dev/hde3 8990 9254 2128581 82 Linux swap
> /dev/hde5 7655 8989 10723356 b W95 FAT32
> /dev/hde6 9255 13128 31117873+ 83 Linux
> /dev/hde7 13129 15651 20265966 83 Linux
> /dev/hde8 15652 19930 34369839 83 Linux
> ==============================================================
>
> Continuing the analysis,
> parted correctly identifies /dev/hde3 as a physical partition.
> It then checks the overlap constraints, as shown by the following stack trace:
> (gdb) where
> #0 _partition_get_overlap_constraint (part=0x8059f10, geom=0x8059f1c)
> at disk.c:1244
> #1 0x4002c3c4 in ped_disk_add_partition (disk=0x8059648, part=0x8059f10,
> constraint=0x8059798) at disk.c:1445
> #2 0x40030db2 in read_table (disk=0x8059648, sector=0, is_extended_table=0)
> at disk_dos.c:832
> #3 0x40031004 in msdos_read (disk=0x8059648) at disk_dos.c:880
> #4 0x4002845e in ped_disk_new (dev=0x805a5b8) at disk.c:148
> #5 0x0804c317 in do_print (dev=0xbffffa94) at parted.c:838
> #6 0x0804a79e in command_run (cmd=0x80581a0, dev=0xbffffa94) at command.c:129
> #7 0x08050e6c in interactive_mode (dev=0xbffffa94, cmd_list=0x8053420)
> at ui.c:1006
> #8 0x0804e608 in main (argc=0, argv=0xbffffb28) at parted.c:1636
>
> Within _partition_get_overlap_constraint, it then chooses a
> max_end that is the end of the disk, part->disk->dev->length - 1
>
> However, for min_start, it walks through each of those physical and extended
> partitions that have a geom.start that is less than the geom.start of
> the current partition. It then chooses a min_start equal to the maximum
> of each value geom.end+1 among the partitions encountered.
>
> The problem is that this assumes that an extended partition like
> /dev/hde2 must be contiguous.
> Since /dev/hde3 is in the hole in the middle of /dev/hde2, the result
> is that /dev/hde3 begins before /dev/hde2, and so the constraint
> insists that /dev/hde2 must end after /dev/hde3. This constraint
> is not satisfied.
>
> A fix for my system would be to make the following change to
> disk.c(_partition_get_overlap_constraint):
> 1244 while (walk != NULL
> 1245 && (walk->geom.start < geom->start
> 1246 || min_start >= walk->geom.start)) {
> 1247 if (walk != part)
> 1248 min_start = walk->geom.end + 1;
> 1249 walk = walk->next;
> 1250 }
> CHANGE TO:
> 1247 if (walk != part && walk->type != PED_PARTITION_EXTENDED)
>
> Of course, this is probably not safe for most situations,
> and so it would be better for me to try the other plan of simply deleting
> my /dev/hde2, and then using parted to recreate it as a logical partition.
> Maybe it would be nice if parted reported when it detected a hole
> in an extended partition:
> disk.c(_partition_get_overlap_constraint):
> ADD BEFORE LINE 1247:
> if (walk->geom.start <= geom->start && walk->geom.end >= geom->end
> && walk->type == PED_PARTITION_EXTENDED
> && part->type == PED_PARTITION_NORMAL)
> PRINT_PED_WARNING("Extended partition has a hole in it, occupied
> by a physical partition.");
> Or is my situation too unusual to worry about?
>
> =====================================
> You can probably skip the rest of this e-mail. But if you want further
> details, here are the partition tables as read by parted.
>
> Running parted under gdb:
>
> [ First invocation of disk_dos.c(read_table) ]
> (gdb) p is_extended_table
> $147 = 0
> (gdb) p table.partitions
> $148 = {{boot_ind = 128 '\200', chs_start = {head = 1 '\001',
> sector = 1 '\001', cylinder = 0 '\0'}, type = 7 '\a', chs_end = {
> head = 254 '', sector = ', cylinder = '}, start = 63,
> length = 122961447}, {boot_ind = 0 '\0', chs_start = {head = 254 '',
> sector = ', cylinder = '}, type = 5 '\005', chs_end = {
> head = 254 '', sector = ', cylinder = '},
> start = 122961510, length = 197211546}, {boot_ind = 0 '\0', chs_start = {
> head = 254 '', sector = ', cylinder = '},
> type = 130 '\202', chs_end = {head = 254 '', sector = ',
> cylinder = '}, start = 144408348, length = 4257162}, {
> boot_ind = 0 '\0', chs_start = {head = 0 '\0', sector = 0 '\0',
> cylinder = 0 '\0'}, type = 0 '\0', chs_end = {head = 0 '\0',
> sector = 0 '\0', cylinder = 0 '\0'}, start = 0, length = 0}}
>
> [ Second recursive invocation of disk_dos.c(read_table) ]
> (gdb) p is_extended_table
> $149 = 1
> (gdb) p table.partitions
> $150 = {{boot_ind = 0 '\0', chs_start = {head = 254 '', sector = ',
> cylinder = '}, type = 11 '\v', chs_end = {head = 254 '',
> sector = ', cylinder = '}, start = 63, length = 21446712}, {
> boot_ind = 0 '\0', chs_start = {head = 254 '', sector = ',
> cylinder = '}, type = 5 '\005', chs_end = {head = 254 '',
> sector = ', cylinder = '}, start = 25704000,
> length = 210901320}, {boot_ind = 0 '\0', chs_start = {head = 0 '\0',
> sector = 0 '\0', cylinder = 0 '\0'}, type = 0 '\0', chs_end = {
> head = 0 '\0', sector = 0 '\0', cylinder = 0 '\0'}, start = 0,
> length = 0}, {boot_ind = 0 '\0', chs_start = {head = 0 '\0',
> sector = 0 '\0', cylinder = 0 '\0'}, type = 0 '\0', chs_end = {
> head = 0 '\0', sector = 0 '\0', cylinder = 0 '\0'}, start = 0,
> length = 0}}
>
> [ Third recursive invocation of disk_dos.c(read_table) ]
> (gdb) p is_extended_table
> $171 = 1
> (gdb) p table.partitions
> $172 = {{boot_ind = 0 '\0', chs_start = {head = 254 '', sector = ',
> cylinder = '}, type = 131 '\203', chs_end = {head = 254 '',
> sector = ', cylinder = '}, start = 63, length = 62235747}, {
> boot_ind = 0 '\0', chs_start = {head = 254 '', sector = ',
> cylinder = '}, type = 5 '\005', chs_end = {head = 254 '',
> sector = ', cylinder = '}, start = 87939810,
> length = 251433315}, {boot_ind = 0 '\0', chs_start = {head = 0 '\0',
> sector = 0 '\0', cylinder = 0 '\0'}, type = 0 '\0', chs_end = {
> head = 0 '\0', sector = 0 '\0', cylinder = 0 '\0'}, start = 0,
> length = 0}, {boot_ind = 0 '\0', chs_start = {head = 0 '\0',
> sector = 0 '\0', cylinder = 0 '\0'}, type = 0 '\0', chs_end = {
> head = 0 '\0', sector = 0 '\0', cylinder = 0 '\0'}, start = 0,
> length = 0}}
>
> [ And so on. ]
>