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The disk labels generated by bsdlabel can no address more than

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0xffffffff sectors.  Document this limit and avoid installing bogus
labels on disks with more sectors.

Allowing the installation of labels addressing as much of the disk as
possiable may be a useful addition in some situations, but this was easy
to implement and should reduce confusion.

PR:		bin/71408
This commit is contained in:
Brooks Davis 2004-09-09 07:46:53 +00:00
parent 030c6fb156
commit 86e0bd0dc0
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=134973
2 changed files with 22 additions and 7 deletions
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26
sbin/bsdlabel/bsdlabel.8
View File

@ -273,7 +273,7 @@ Lowercase versions of
and
.Cm G
are allowed.
Size and type should be specifed without any spaces between them.
Size and type should be specified without any spaces between them.
.Pp
Example: 2097152, 1G, 1024M and 1048576K are all the same size
(assuming 512-byte sectors).
@ -408,8 +408,8 @@ Display what the label would be for
.Pa da0s1
using the partition layout in
.Pa label_layout .
This is useful for determining how much space would be alloted for various
partitions with a labelling scheme using
This is useful for determining how much space would be allotted for various
partitions with a labeling scheme using
.Cm % Ns -based
or
.Cm *
@ -468,6 +468,20 @@ which could be used as a source file for
f: 5g * 4.2BSD
g: * * 4.2BSD
.Ed
.Sh DIAGNOSTICS
The kernel device drivers will not allow the size of a disk partition
to be decreased or the offset of a partition to be changed while it is open.
.Sh COMPATIBILITY
Due to the use of an
.Vt u_int32_t
to store the number of sectors,
bsdlabels are restricted to a maximum of 2^32-1 sectors.
This usually means 2TB of disk space.
Larger disks should be partitioned using another method such as
.Xr gpt 8 .
.Pp
The various BSDs all use slightly different versions of BSD labels and
are not generally compatible.
.Sh SEE ALSO
.Xr ccd 4 ,
.Xr geom 4 ,
@ -475,7 +489,5 @@ which could be used as a source file for
.\" Xr bsdlabel 5 ,
.Xr disktab 5 ,
.Xr boot0cfg 8 ,
.Xr fdisk 8
.Sh DIAGNOSTICS
The kernel device drivers will not allow the size of a disk partition
to be decreased or the offset of a partition to be changed while it is open.
.Xr fdisk 8 ,
.Xr gpt 8

3
sbin/bsdlabel/bsdlabel.c
View File

@ -477,6 +477,9 @@ readlabel(int flag)
(ioctl(f, DIOCGSECTORSIZE, &secsize) != 0)) {
err(4, "cannot get disk geometry");
}
if (mediasize > (off_t)0xffffffff * secsize)
errx(1,
"disks with more than 2^32-1 sectors are not supported");
(void)lseek(f, (off_t)0, SEEK_SET);
if (read(f, bootarea, BBSIZE) != BBSIZE)
err(4, "%s read", specname);