growing filesystems in 5-current

[Lukas Ertl]

On Thu, 17 Apr 2003, Terry Lambert wrote:

> ...and also consists of 3 elements, following "start", so it
> seems you aren't losing anything, at least to me.
>
> Probably your patch is fine.

Thanks for your answer, Terry, seems reasonable.

There's still a thing that I have recognized now and that bothers me, and
I can't explain this one too.

Consider again this 32 MB vinum volume. If I newfs it with the default
size of 65536 sectors I get this:

---8<---
# newfs -O2 -s 65536 /dev/vinum/mytest
/dev/vinum/mytest: 32.0MB (65536 sectors) block size 16384, fragment size
2048
        using 4 cylinder groups of 8.02MB, 513 blks, 1088 inodes.
super-block backups (for fsck -b #) at:
 160, 16576, 32992, 49408

# df -k /dev/vinum/mytest
Filesystem          1K-blocks     Used    Avail Capacity  Mounted on
/dev/vinum/mytest       31470        2    28952    0.%
---8<---

Four cg's with 8.02MB each? 513 blocks? Why's that? Shouldn't that be 8MB
each and 512 blocks?

If I growfs this one I get the behaviour I described in my first mail.

Now look at this:

---8<---
# newfs -O2 -s 65535 /dev/vinum/mytest
/dev/vinum/mytest: 32.0MB (65532 sectors) block size 16384, fragment size
2048
        using 4 cylinder groups of 8.00MB, 512 blks, 1024 inodes.
super-block backups (for fsck -b #) at:
 160, 16544, 32928, 49312

# df -k /dev/vinum/mytest
Filesystem          1K-blocks     Used    Avail Capacity  Mounted on
/dev/vinum/mytest       31532        2    29008    0.%
---8<---

So I explicitly make the FS one sector smaller than the default value, and
I get not only 4 cg's with 8 MB and 512 blocks (which would seem correct
to me), but I also get more space available on the FS.

And if I growfs this one, everything works as expected:

---8<---
# growfs /dev/vinum/mytest
We strongly recommend you to make a backup before growing the Filesystem

 Did you backup your data (Yes/No) ? Yes
new file systemsize is: 32768 frags
growfs: 64.0MB (131072 sectors) block size 16384, fragment size 2048
        using 8 cylinder groups of 8.00MB, 512 blks, 1024 inodes.
super-block backups (for fsck -b #) at:
 65696, 82080, 98464, 114848
---8<---

What the heck is going on here? newfs bug? Or did I get something wrong?

best regards,
le

-- 
Lukas Ertl                             eMail: l.ertl at univie.ac.at
UNIX-Systemadministrator               Tel.:  (+43 1) 4277-14073
Zentraler Informatikdienst (ZID)       Fax.:  (+43 1) 4277-9140
der Universität Wien                   http://mailbox.univie.ac.at/~le/