,ad8888ba, 88888888888 ad88888ba d8"' `"8b 88 d8" "8b d8' 88 Y8, 88 ,adPPYba, 8b,dPPYba, 8b d8 88aaaaa `Y8aaaaa, 88 a8" "8a 88P' "8a `8b d8' 88""""" `"""""8b, Y8, 8b d8 88 d8 `8b d8' 88 `8b Y8a. .a8P "8a, ,a8" 88b, ,a8" `8b,d8' 88 Y8a a8P `"Y8888Y"' `"YbbdP"' 88`YbbdP"' Y88' 88 "Y88888P" 88 d8' 88 d8' 1.0.1 A copy-on-write, versionned filesystem By Nicolas Vigier (boklm@mars-attacks.org) and Thomas Joubert (widan@net-42.eu.org) http://n0x.org/copyfs/ CopyFS aims to solve a common problem : given a directory, especially one full of configuration files, or other files that one can modify, and which can affect the functionning of a system, or of programs, that may be important to other users (or to the user himself), how to be sure that a person modifying the files will do a backup of the working version first ? This filesystem solves the problem by making the whole process transparent, automatically keeping versionned copies of all the changes done to file under its control. It also allows a user to select an old version of the files, for example to repair a mistake, and allows him/her to continue edition from this point. CopyFS is distributed under the terms of the GNU GPL. System requirements ------------------- Filesystem in Userspace (FUSE) is required to use this filesystem. FUSE was merged into the mainstream Linux kernel tree in kernel version 2.6.14, so any version >= 2.6.14 should be fine, if the option was selected when the kernel was compiled. More informations about FUSE is available on http://fuse.sourceforge.net/ It might work on FreeBSD and OpenSolaris too, but we never tried yet. How to install -------------- Simply do : copyfs-1.0 % ./configure copyfs-1.0 % make all copyfs-1.0 % su Password: copyfs-1.0 # make install How to use ---------- To mount a CopyFS, you need to use the command 'copyfs-mount' : if you want to mount a CopyFS at '/mnt/fs', whose version directory is at /var/versions, you would use : root # copyfs-mount /var/versions /mnt/fs To unmount it, simply do : root # umount /mnt/fs As you would do for any filesystem. Accessing old versions ---------------------- To know which versions are available, you can use the copyfs-fversion tool : cpy-fs $ copyfs-fversion test File test ('*' is active) : v1.0 : -rw-r--r-- widan users 0 Fri Dec 10 14:17:47 2004 v2.0 : -rw-r--r-- widan users 21 Fri Dec 10 14:17:55 2004 v2.1 : -rwx------ widan users 21 Fri Dec 10 14:17:55 2004 v3.0 : -rwx------ widan users 29 Fri Dec 10 14:19:35 2004 [*] You know there are 4 versions, with their associated information. In that state you are viewing version 3.0 (ie the last one). If you want to see another one, you can 'lock' it : cpy-fs $ cat test version 3.0 cpy-fs $ copyfs-fversion -l 2.0 test cpy-fs $ cat test version 2.0 If you want to remove the version lock, and return to the latest version available, use : cpy-fs $ copyfs-fversion -r test Tagging files ------------- Let's say you have the following file tree : cpy-fs $ copyfs-fversion somedir/file-1 File file-1 ('*' is active) : v1.0 : -rw-r--r-- widan users 3 Fri Dec 10 14:21:41 2004 v2.0 : -rw-r--r-- widan users 3 Fri Dec 10 14:21:43 2004 [*] v3.0 : -rw-r--r-- widan users 3 Fri Dec 10 14:21:45 2004 cpy-fs $ copyfs-fversion somedir/file-2 File file-2 ('*' is active) : v1.0 : -rw-r--r-- widan users 5 Fri Dec 10 14:21:51 2004 [*] v2.0 : -rw-r--r-- widan users 5 Fri Dec 10 14:21:53 2004 cpy-fs $ copyfs-fversion somedir/file-3 File file-3 ('*' is active) : v1.0 : -rw-r--r-- widan users 5 Fri Dec 10 14:21:58 2004 v2.0 : -rw-r--r-- widan users 5 Fri Dec 10 14:22:03 2004 [*] You have : cpy-fs $ cat somedir/file-1 v2 cpy-fs $ cat somedir/file-2 2 v1 cpy-fs $ cat somedir/file-3 3 v2 Suppose you want to save all the "current" versions for the directory 'somedir', you can create a tag file with : cpy-fs $ copyfs-fversion -t tag-file somedir Then you can edit the files as you want, and if you want to put all the files back to the version they were at when you tagged them, simply do : cpy-fs $ copyfs-fversion -u tag-file somedir Example : cpy-fs $ echo "new 1" > somedir/file-1 cpy-fs $ echo "new 2" > somedir/file-2 cpy-fs $ cat somedir/file-{1,2,3} new 1 new 2 3 v2 cpy-fs $ copyfs-fversion -t tag-file-new somedir cpy-fs $ copyfs-fversion -u tag-file somedir Restored somedir/file-1 to version 2.0 Restored somedir/file-2 to version 1.0 Restored somedir/file-3 to version 2.0 cpy-fs $ cat somedir/file-{1,2,3} v2 2 v1 3 v2 cpy-fs $ copyfs-fversion -u tag-file-new somedir Restored somedir/file-1 to version 6.0 Restored somedir/file-2 to version 3.0 Restored somedir/file-3 to version 2.0 cpy-fs $ cat somedir/file-{1,2,3} new 1 new 2 3 v2