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%
% Copyright (c) 1998 University of Utah and the Flux Group.
% All rights reserved.
%
% The University of Utah grants you the right to copy and reproduce this
% document or portions thereof for academic, research, evaluation, and
% personal use only, provided that (1) the title page appears prominently,
% and (2) these copyright and permission notices are retained in all copies.
% To arrange for alternate terms, contact the University of Utah at
% csl-dist@cs.utah.edu or +1-801-585-3271.
%
\label{linux-fs}
The Linux filesystem library consists of the Linux virtual and real
filesystem code along with glue code to export the \oskit{} filesystem
interface (See Chapter~\ref{fs}).
The header file \texttt{<oskit/fs/linux_filesystems.h>} determines which
of the real Linux real filesystems, e.g.\ \texttt{ext2}, \texttt{iso9660},
are compiled into \texttt{liboskit_linux_fs.a}.
All the filesystems listed in that file will compile,
but only \texttt{ext2}, \texttt{msdos}, \texttt{vfat}, and \texttt{iso9660}
have been tested.
The Linux filesystem library provides two additional interfaces:
\begin{icsymlist}
\item[fs_linux_init]
Initialize the Linux fs library.
\item[fs_linux_mount]
Mount a filesystem via the Linux fs library
\end{icsymlist}
\api{fs_linux_init}{Initialize the Linux fs library}
\begin{apisyn}
\cinclude{oskit/fs/linux.h}
\funcproto oskit_error_t fs_linux_init(void);
\end{apisyn}
\ostofs
\begin{apidesc}
This function initializes the Linux fs library,
and must be invoked prior to the first
call to {\tt fs_linux_mount}. This function only
needs to be invoked once by the client
operating system.
All filesystems listed in \texttt{<oskit/fs/linux_filesystems.h>}
are initialized.
\end{apidesc}
\begin{apiret}
Returns 0 on success, or an error code specified in
{\tt <oskit/error.h>}, on error.
\end{apiret}
\api{fs_linux_mount}{Mount a filesystem via the Linux fs library}
\begin{apisyn}
\cinclude{oskit/fs/linux.h}
\funcproto oskit_error_t fs_linux_mount(oskit_blkio_t *bio,
oskit_u32_t flags,
oskit_filesystem_t **out_fs);
\end{apisyn}
\ostofs
\begin{apidesc}
This function looks in the partition described by \texttt{bio}
for a filesystem superblock, calls the corresponding
filesystem mount code,
and returns a handle to an \texttt{oskit_filesystem_t} for
this filesystem.
This function may be used multiple times by a client
operating system to mount multiple file systems.
Note that this function does not graft the filesystem
into a namespace; {\tt oskit_dir_reparent} or other layers
may be used for that purpose.
Typically, this interface is not exported to clients,
and is only used by the client operating system
during initialization.
This function is a wrapper for Linux's \texttt{mount_root}.
\end{apidesc}
\begin{apiparm}
\item[bio]
Describes the partition containing a filesytem.
Can be the whole disk like that returned from
\texttt{oskit_linux_block_open},
or a subset of one like what is given by
\texttt{diskpart_blkio_lookup_bsd_string}.
\item[flags]
The mount flags.
These are formed by or'ing the following values:
\begin{description}
\item[OSKIT_FS_RDONLY] Read only filesystem
\item[OSKIT_FS_NOEXEC] Can't exec from filesystem
\item[OSKIT_FS_NOSUID] Don't honor setuid bits on fs
\item[OSKIT_FS_NODEV] Don't interpret special files
\end{description}
\item[out_fs]
Upon success, is set to point to an \texttt{oskit_filesystem_t}
for this filesystem.
\end{apiparm}
\begin{apiret}
Returns 0 on success, or an error code specified in
{\tt <oskit/error.h>}, on error.
\end{apiret}
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