In message <158EF4B20EA8C84D9DC71A55216D2E1C066C5C at csy-exchange1.giat.intra>
you wrote:
>
> > Your new filesystem is twice as big as the old one, so it will have
> > more inode blocks etc. Also, you may notice that our filesystem image
> > does not contain the (rather large) lost+found firectory.
>
> How come the lost+found directory is large, or even has a single entry
> to begin with? I thought it was used by fsck to collect file data lost
> due to file system corruption over time; so in a freshly built embedded
> image, there shouldn't be any of that. Did I miss something?
When the filesystem is created (by mke2fs) special care is taken to
create a big directory that allows for many entries to be reconnected
without need to grow the directory which could be dangerous on an
already corrupted filesystem. Have a look:
# ls -l
total 12
drwx------ 2 root root 12288 Dec 11 10:14 lost+found
# df .
Filesystem 1K-blocks Used Available Use% Mounted on
/tmp/rd 63461 13 63448 1% /mnt/tmp
# rmdir lost+found/
# df .
Filesystem 1K-blocks Used Available Use% Mounted on
/tmp/rd 63461 1 63460 1% /mnt/tmp
As you can see the "lost+found" as created by the "mke2fs" tool
occupies 12kB of filesystem space which get freed when you remove the
directory.
# mkdir lost+found
# ls -l
total 1
drwxr-xr-x 2 root root 1024 Dec 11 10:15 lost+found
# df .
Filesystem 1K-blocks Used Available Use% Mounted on
/tmp/rd 63461 2 63459 1% /mnt/tmp
If you manually create a directory it will occupy only 1 kB instead.
In older times you used to run something like
for i in 0 1 2 3 4 5 6 7 8 9 ; do
for j in 0 1 2 3 4 5 6 7 8 9 ; do
for k in 0 1 2 3 4 5 6 7 8 9 ; do
touch lost+found/${i}${j}${k}
done ; done ; done
rm -f lost+found/*
to "blow up" the lost+found/ directory to allow for a sufficiently
large number of directory entries. Today mke2fs does this
automagically (and people forget why it needs to be done).
Best regards,
Wolfgang Denk
--
Software Engineering: Embedded and Realtime Systems, Embedded Linux
Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: wd at denx.de
Why can you only have two doors on a chicken coop? If it had four it
would be a chicken sedan.
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