+++ /dev/null
-Filesystems supported by ADFS
------------------------------
-
-The ADFS module supports the following Filecore formats which have:
-
-- new maps
-- new directories or big directories
-
-In terms of the named formats, this means we support:
-
-- E and E+, with or without boot block
-- F and F+
-
-We fully support reading files from these filesystems, and writing to
-existing files within their existing allocation. Essentially, we do
-not support changing any of the filesystem metadata.
-
-This is intended to support loopback mounted Linux native filesystems
-on a RISC OS Filecore filesystem, but will allow the data within files
-to be changed.
-
-If write support (ADFS_FS_RW) is configured, we allow rudimentary
-directory updates, specifically updating the access mode and timestamp.
-
-Mount options for ADFS
-----------------------
-
- uid=nnn All files in the partition will be owned by
- user id nnn. Default 0 (root).
- gid=nnn All files in the partition will be in group
- nnn. Default 0 (root).
- ownmask=nnn The permission mask for ADFS 'owner' permissions
- will be nnn. Default 0700.
- othmask=nnn The permission mask for ADFS 'other' permissions
- will be nnn. Default 0077.
- ftsuffix=n When ftsuffix=0, no file type suffix will be applied.
- When ftsuffix=1, a hexadecimal suffix corresponding to
- the RISC OS file type will be added. Default 0.
-
-Mapping of ADFS permissions to Linux permissions
-------------------------------------------------
-
- ADFS permissions consist of the following:
-
- Owner read
- Owner write
- Other read
- Other write
-
- (In older versions, an 'execute' permission did exist, but this
- does not hold the same meaning as the Linux 'execute' permission
- and is now obsolete).
-
- The mapping is performed as follows:
-
- Owner read -> -r--r--r--
- Owner write -> --w--w---w
- Owner read and filetype UnixExec -> ---x--x--x
- These are then masked by ownmask, eg 700 -> -rwx------
- Possible owner mode permissions -> -rwx------
-
- Other read -> -r--r--r--
- Other write -> --w--w--w-
- Other read and filetype UnixExec -> ---x--x--x
- These are then masked by othmask, eg 077 -> ----rwxrwx
- Possible other mode permissions -> ----rwxrwx
-
- Hence, with the default masks, if a file is owner read/write, and
- not a UnixExec filetype, then the permissions will be:
-
- -rw-------
-
- However, if the masks were ownmask=0770,othmask=0007, then this would
- be modified to:
- -rw-rw----
-
- There is no restriction on what you can do with these masks. You may
- wish that either read bits give read access to the file for all, but
- keep the default write protection (ownmask=0755,othmask=0577):
-
- -rw-r--r--
-
- You can therefore tailor the permission translation to whatever you
- desire the permissions should be under Linux.
-
-RISC OS file type suffix
-------------------------
-
- RISC OS file types are stored in bits 19..8 of the file load address.
-
- To enable non-RISC OS systems to be used to store files without losing
- file type information, a file naming convention was devised (initially
- for use with NFS) such that a hexadecimal suffix of the form ,xyz
- denoted the file type: e.g. BasicFile,ffb is a BASIC (0xffb) file. This
- naming convention is now also used by RISC OS emulators such as RPCEmu.
-
- Mounting an ADFS disc with option ftsuffix=1 will cause appropriate file
- type suffixes to be appended to file names read from a directory. If the
- ftsuffix option is zero or omitted, no file type suffixes will be added.
git.samba.org / sfrench / cifs-2.6.git / blobdiff