Hi, I am using kernel 2.6.15.4. On my system, I first created a partition with EXT3 and put some data on it. Later, I deleted the partition, and re-created another partition with the same starting block number and a higher ending block number. I intended to format it with another filesystem, but surprisingly (or maybe just to me), the superblock of the partition had not changed. I could still mount the new partition as the same old filesystem. I could see all the files which was present earlier. Doing 'df' showed me the older partition details (size, % used etc.). Shouldn't the superblock be changed/deleted once the partition is deleted? I tried a reboot, but the output remained the same. -- Sumit
On Thu, 2006-04-06 14:37:33 +0800, Sumit Narayan <talk2sumit at gmail.com> wrote:> Shouldn't the superblock be changed/deleted once the partition is > deleted? I tried a reboot, but the output remained the same.No, everything you see is "works as expected." A partition is only a container (as well as "disks", "volume groups", "RAID arrays", "logical volumes", "image files" etc. are.) Whenever you destroy such a container, its contents isn't modified (or deleted) or otherwise modified. So it's perfectly okay to delete such a container (eg. remove start and end from the partition table) and recreate it at some time later (by adding those values back to the partition table.) As long as the new container starts at the same location, a filesystem driver will be able to find the old information. If you start a block later, it won't find it's superblocks. Finally, you have several choices how to defeat getting back old data. Most probably, you'd just zero it out before deleting the partition with something like: # cat /dev/zero > /dev/hda3 (of course with the correct device name!) MfG, JBG -- Jan-Benedict Glaw jbglaw at lug-owl.de . +49-172-7608481 _ O _ "Eine Freie Meinung in einem Freien Kopf | Gegen Zensur | Gegen Krieg _ _ O f?r einen Freien Staat voll Freier B?rger" | im Internet! | im Irak! O O O ret = do_actions((curr | FREE_SPEECH) & ~(NEW_COPYRIGHT_LAW | DRM | TCPA)); -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 189 bytes Desc: Digital signature URL: <http://listman.redhat.com/archives/ext3-users/attachments/20060406/b3a0e144/attachment.sig>
On Thu, 6 Apr 2006, Sumit Narayan wrote:> On my system, I first created a partition with EXT3 and put some data > on it. Later, I deleted the partition, and re-created another > partition with the same starting block number and a higher ending > block number. I intended to format it with another filesystem, but > surprisingly (or maybe just to me), the superblock of the partition > had not changed. I could still mount the new partition as the same old > filesystem. I could see all the files which was present earlier. Doing > 'df' showed me the older partition details (size, % used etc.). > > Shouldn't the superblock be changed/deleted once the partition is > deleted? I tried a reboot, but the output remained the same.This is the expected behavior. A filesystem is created within the partition. If you grow the partition, the filesystem doesn't automatically grow (use resize2fs for that). In fact, you should probably read the resize2fs manpage, as it might give you some starting clue of what's going on. Damian Menscher -- -=#| <menscher at uiuc.edu> www.uiuc.edu/~menscher/ Ofc:(650)253-2757 |#=- -=#| The above opinions are not necessarily those of my employers. |#=-