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fixing a bug in test mode (growfs -N)

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Submitted by: 	Chris Boltwood <chris@hiendmedia.com>
Reviewed by:	tomsoft
MFC after:	5 days
This commit is contained in:
chm 2001-08-08 21:45:42 +00:00
parent f47e26cdfd
commit a870ec0047
2 changed files with 76 additions and 36 deletions
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97
sbin/growfs/growfs.8
View File

@ -53,23 +53,24 @@
extends the
.Xr newfs 8
program.
Before running
Before starting
.Nm
the disk must be labeled to a bigger size using
.Xr disklabel 8 .
If you are using volumes you must grow them using
If you are using volumes you must enlarge them by using
.Xr vinum 8 .
.Nm
extends the size of the file system on the specified special file.
Currently
.Nm
can only grow unmounted file systems.
Do not try growing a mounted file system, your system may panic and you will
can only enlarge unmounted file systems.
Do not try enlarging a mounted file system, your system may panic and you will
not be able to use the file system any longer.
Most of the options you have used with
Most of the
.Xr newfs 8
once can not be changed.
In fact you can only increase the size of the file system.
options can not be changed by
.Nm
In fact, you can only increase the size of the file system.
Use
.Xr tunefs 8
for other changes.
@ -77,69 +78,93 @@ for other changes.
The following options are available:
.Bl -tag -width indent
.It Fl N
Cause the new file system parameters to be printed out without actually growing
the file system.
.Dq Test mode .
Causes the new file system parameters to be printed out without actually
enlarging the file system.
.It Fl y
.Dq Expert mode .
Normally
Usally
.Nm
will ask you, if you took a backup of your data before and will do some tests
if
will ask you if you took a backup of your data before and will do some tests
wether
.Ar special
is currently mounted or if there are any active snapshots on the filesystem
specified.
is currently mounted or wether there are any active snapshots on the file
system specified.
This will be suppressed.
So use this option with great care!
.It Fl s Ar size
The
Determines the
.Ar size
of the file system after growing in sectors.
of the file system after enlarging in sectors.
This value defaults to the size of the raw partition specified in
.Ar special
(in other words,
.Nm
will grow the file system to the size of the entire partition).
will enlarge the file system to the size of the entire partition).
.El
.Sh EXAMPLES
.Dl growfs -s 4194304 /dev/vinum/testvol
.Pp
will grow
will enlarge
.Pa /dev/vinum/testvol
up to 2GB if there is enough space in
.Pa /dev/vinum/testvol .
.Sh BUGS
In some cases on
.Fx
3.x it is possible, that
.Nm
did not recognize exactly, if the file system is mounted or not and
exits with an error message, then use
works starting with
.Fx
3.x.
There may be cases on
.Fx
3.x only, when
.Nm
does not recognize exactly, wether the file system is mounted or not and
exits with an error message.
Then please use
.Nm
.Fl y
if you are sure, that the file system is not mounted.
It is also recommended to always use
.Xr fsck 8
after growing just to be on the safe side.
after enlarging (just to be on the safe side).
.Pp
Pay attention, as in certain cases we have to change the location of an file
system internal structure which had never been moved before.
Almost everything works perfect with this relocated structure except the
.Xr fsck 8
utility.
There is a patch available for
.Xr fsck 8 .
For growing above certain limits it is essential to have some free blocks
For enlarging beyond certain limits, it is essential to have some free blocks
available in the first cylinder group.
To avoid the relocation of that structure it is currently recommended to use
If that space is not available in the first cylinder group, a critical data
structure has to be relocated into one of the new available cylinder groups.
On
.Fx
3.x this will cause problems with
.Nm fsck
afterwards.
So
.Nm fsck
needs to be patched if you want to use
.Nm
for
.Fx
3.x. This is patch is already integrated in
.Fx
starting with 4.4.
To avoid an unexpected relocation of that structure it is possible to use
.Nm ffsinfo
.Fl c Ar 0
on the first cylinder group and check that
on the first cylinder group to verify that
.Em nbfree
in the CYLINDER SUMMARY (internal cs) of the CYLINDER GROUP
.Em cgr0
has enough blocks.
As a rule of thumb for default filesystem parameters a block is needed for
every 2 GB of total filesystem size.
As a rule of thumb for default file system parameters one block is needed for
every 2 GB of total file system size.
.Pp
Normally
.Nm
writes this critical structure to disk and reads it again later for doing more
updates.
This read operation will provide unexpected data, when using
.Fl N .
Therefore, this part can not really be simulated and will be skiped in test
mode.
.Sh SEE ALSO
.Xr disklabel 8 ,
.Xr dumpfs 8 ,

15
sbin/growfs/growfs.c
View File

@ -956,6 +956,9 @@ updcsloc(time_t utime, int fsi, int fso, unsigned int Nflag)
/*
* Read original cylinder group from disk, and make a copy.
* XXX If Nflag is set in some very rare cases we now miss
* some changes done in updjcg by reading the unmodified
* block from disk.
*/
rdfs(fsbtodb(&osblock, cgtod(&osblock, ocscg)),
(size_t)osblock.fs_cgsize, (void *)&aocg, fsi);
@ -1136,6 +1139,18 @@ updcsloc(time_t utime, int fsi, int fso, unsigned int Nflag)
ncscg=dtog(&sblock, sblock.fs_csaddr);
cs=fscs+ncscg;
/*
* If Nflag is specified, we would now read random data instead
* of an empty cg structure from disk. So we can't simulate that
* part for now.
*/
if(Nflag) {
DBG_PRINT0("nscg update skipped\n");
DBG_LEAVE;
return;
}
/*
* Read the future cylinder group containing the cylinder
* summary from disk, and make a copy.