It was mentioned earlier this week that UFS2 snapshots could somehow be mounted read/write and then written to. I noticed this a few weeks ago but didn't think much of it.
I have reproduced this: mksnap_ffs / /snap1 mkdir /snapmount mdconfig -a -t vnode -f /snap1 -u 4 mount -r /dev/md4 /snapmount So far so good ... now enter the mounted snapshot and attempt to write a file: # cd /snapmount/ # touch test touch: test: Read-only file system # This is the expected behavior. However: # # pwd /snapmount # mount -uw /snapmount # touch test # echo sldkfslk >> /snapmount/test # # cat /snapmount/test sldkfslk # This is unexpected. You can successfully mount the snapshot read/write and create and write to files in that snapshot. You can also write to files that existed in the snapshot prior to mounting it read/write. I have confirmed that if you unmount the snapshot and remount it again normally, the created file(s) still exist in it, and any changes made to existing files in the snapshot are persistent as well. I don't know what context this was being discussed in, but this behavior does indeed exist, and I believe it to be a somewhat serious problem. ----- John Kozubik - [EMAIL PROTECTED] - http://www.kozubik.com _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
