1FUNIONFS(8) FUNIONFS(8)
2
6 funionfs - user-space directory concatenation.
7
9 funionfs upper_dir mountpoint [ option ] ...
10
12 -o opt,[opt...] mount options
13 -h --help print help
14 -V --version print version
15 Mount options include:
17 funionfs_debug print some debugging information
18 dirs=LIST A colon separated list of directories
19 /branch1=rw a directory in a read-write mode
20 /branch1 if no permission is specified, the branch
21 is in a read-write mode
22 /branch2=ro a directory in a read-only mode
23 copyupuid=N uid of the copied-up files (no default)
24 copyupgid=N gid of the copied-up files (no default)
25 copyupmode=N mode of the copied-up files (no default)
26 del_string=N string to mark a deleted file(default: _DELETED~
27 )
28 delete=TYPE specifies how funionfs deletes and renames
29 all (default) delete all objects in read-write branch
30 (default)
31 and add a whiteout file if objects exists in
32 read-only branches.
33 whiteout only add a whiteout file in upper (rw) branch
34 or delete file in upper branch.
35 copyup=TYPE specifies how to manage attributes
36 preserve preserve uid, gid and mode of object (default)
37 currentuser the object owns to the user doing the operation
38 mounter the object owns to the mounter
39 There is no implementation of -o delete and -o copyup for now.
41 You could use the mount command instead :
43 mount -t fuse funionfs#/upper_dir mountpoint [ options ]
44 If you want to name all directories in '-o dirs=', then pass "none" as
46 upper_dir
47
50 funionfs concatenates directories mentioned in options (and upper_dir )
51 to mountpoint. Also, although some (but not all) of the directories
52 are read-only, you still can write in resulting mounted directory. For
53 example, if you have files a/a and b/b and mount mountpoint r with "-o
54 dirs=a=ro:b=ro:w=rw", then you will see files r/a and r/b. You will be
55 able to write to them, and original files will remain intact (changes
56 will go to w ). Note that it is impossible to have file with name end‐
57 ing by del_string value, if you create r/a_DELETED~ in mentioned exam‐
58 ple, it will dissapear together with a.
59
61 The source..
62
64 You cannot mount an overlay on / (the program that list the content of
65 / will hang). This is probably due to a loop call of the fuse driver.
66 There is no known solution for now.
67 Probably minor (or major) mistakes in not-so-frequent cases.
69 Not enough tested.
71 15 June 2006 FUNIONFS(8)