Even after umount file doesnt disappear
1)mount -t ext4 /dev/loop4 /mnt/
2)cd /mnt
3)ls
a.c lost+found
4)cd -
4)umount /mnt
5)mount -t ext4 /dev/loop4 /mnt/
6) cd /mnt/
7)
[r...@localhost mnt]# ls
a.c lost+found
I m guessing ...is this somewhere related to that its showing data
from page cache but not from disk ?
On Fri, Mar 5, 2010 at 7:13 PM, Greg Freemyer <[email protected]>wrote:
> On Fri, Mar 5, 2010 at 6:37 AM, nidhi mittal hada
> <[email protected]> wrote:
> >
> > hi all
> > I created a loop device
> > /dev/loop0 ------------>with the image file ---------->file.img
> > then
> > mkfs and
> > mount /dev/loop0 to /mnt
> >
> > cd /mnt
> > created files a.c , b.c
> > rm file.img ------- removed file.img
> >
> > cd /mnt
> > still i am able to see a.c b.c here
> > How are these files present here ?
> > they should have been deleted as underlying storage file is no where
> present
> > !!
>
> Nidhi,
>
> For this think of rm as what it really is "unlink".
>
> When you unlink a file all that happens is the directory entry for
> that link is tagged as deleted / reusable, and the link count field in
> the inode is decremented by one.
>
> After the decrement there is code to do:
>
> if (inode.link_count == 0 and inode.is_open == 0) then delete inode
> and associated data blocks.
>
> When your loop mount is unmounted it should close the fd associated
> with the image file and invoke the above logic again which I assume at
> that point will cause the inode and data blocks to be freed up.
>
> Greg
>
--
Thanks & Regards
Nidhi Mittal Hada
Scientific officer D
Computer Division
Bhabha Atomic Research Center
Mumbai
