1FUNIONFS(8)                                                        FUNIONFS(8)
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NAME

6       funionfs - user-space directory concatenation.
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SYNOPSIS

9       funionfs upper_dir mountpoint [ option ] ...
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OPTIONS

12           -o opt,[opt...]        mount options
13           -h   --help            print help
14           -V   --version         print version
15
16       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
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40       There is no implementation of -o delete and -o copyup for now.
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42       You could use the mount command instead :
43          mount -t fuse funionfs#/upper_dir mountpoint [ options ]
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45       If  you want to name all directories in '-o dirs=', then pass "none" as
46       upper_dir
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DESCRIPTION

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.
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SEE ALSO

61       The source..
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BUGS

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.
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68       Probably minor (or major) mistakes in not-so-frequent cases.
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70       Not enough tested.
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74                                 15 June 2006                      FUNIONFS(8)
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