Messages in this thread | | | Date | Thu, 4 Mar 1999 19:47:56 +0200 (EET) | From | Tuomas Heino <> | Subject | Re: EXT2_UNRM_FL |
| |
On Wed, 3 Mar 1999, Theodore Y. Ts'o wrote:
> Date: Wed, 3 Mar 1999 18:21:48 -0500 (EST) > From: Alexander Viro <viro@math.psu.edu> > > Sorry, I've misparsed it ;-< What I was thinking of is > NO_UNLINK stuff - behaves as APPEND_ONLY and IMMUTABLE wrt link > creation/removing and gives no protection to the contents of file. > It is useful in many situations and it *is* easy to implement. > But yes, UNRM is different... Actually I'ld propose to take one more bit > of attributes for that. UFS has such thing (ignored in Linux) and VFS > support for that would be very easy to add (I already did VFS part and > changes to UFS driver). Could you comment on that? All I need on ext2 side > is a spare bit in ext2_i.i_flags (user-visible). > > I guess I'm little confused about how NO_UNLINK would be useful. Does > it protect against file renames as well as unlinks? What about > truncates? If it doesn't protect the data, what are the applications > where it's useful?
Very useful for all kinds of "must-exist" files... IAW lock files etc (especially when you're using a stupid Linux distribution which keeps messing with your files and you're too lazy to check out what it's doing;)
... now this raises another question to my mind: Would it be possible to create immutable symlinks in a clean way w/ ext2?
# pwd /var/run # ls -ld . mysql* mysql/* drwxr-xr-x 4 root root 1024 Mar 4 19:44 . drwxr-xr-x 2 mysql mysql 1024 Feb 23 15:56 mysql lrwxrwxrwx 1 root root 16 Mar 4 19:44 mysql.sock -> mysql/mysql.sock srwxrwxrwx 1 mysql root 0 Feb 23 15:56 mysql/mysql.sock -rw-r--r-- 1 mysql root 3 Feb 23 15:56 mysql/mysqld.pid lrwxrwxrwx 1 root root 16 Mar 4 19:44 mysqld.pid -> mysql/mysqld.pid
... get my point on why immutable symlinks would be very useful? ;)
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |