fs: add pread and pwrite functions ...

Add pread and pwrite functions.

Split read and write functions to save some space.
The functions pread and pwrite saves and sets the file
position to a given offset and restore them afterwards.

This also makes the nandtest command use these function
which is necessary to not break compilation for the nandtest
command.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: fix return type of read ...

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Add write_file function ...

write_file() will write a buffer to a file. The file is created
if necessary.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

rm: implement -r ...

To recursively remove files and directories.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Merge branch 'for-next/link'

fs: introduce get_mounted_path to get the path where a file is mounted ...

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

fs: implement stat ...

stat() stats the file pointed to by path and fills in buf.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

fs: add symlink support ...

Limit it's support to existing file only

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

fs: rename stat to lstat as we implement lstat ...

For compatibility put a inline on lstat for stat until we have the symlink
support.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

fs: add readlink support ...

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

fs/mount: add autodetection type support ...

if NULL is pass as type mount will try to autodetect the filesystem type

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

fs: fix standard zero, full devices ...

The standard devices are currently broken since they have
the size ~0. As now files use loff_t as file size which is a signed
type the read implementation gets confused and now returns -1.

The current implementation also has the (somewhat theorical) problem
that we do not have real streaming devices, so /dev/zero went out
of zeroes after reading 4GB (or now LLONG_MAX).

This patch introduces a new cdev flag DEVFS_IS_CHARACTER_DEV and a new
file size flag FILE_SIZE_STREAM which makes it possible to create
real stream devices instead.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

use loff_t for file offsets ...

This is a first step for 64bit file support: Make the file sizes/offsets
64bit.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Add automount support ...

This patch adds an automount command which makes it possible
to execute a script when a certain directory is first accessed.
It's the commands responsibility to make this directory available
(bringing devices up and mounting it). This results in automount
support which makes sure that from the shell every file can
be accessed without having to care for device bringup. Bringing
up devices may be expensive (USB, dhcp). The automount support
makes it easy for the environment to bringup devices when they
are actually needed.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: drop struct mtab_entry ...

every struct fs_device_d contains a struct mtab_entry, so they
have a 1:1 relationship. Instead of having to use container_of
to get from a struct mtab_entry to a struct fs_device_d we can
better embed the members of struct mtab_entry into struct fs_device_d
directly.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: get fs device using container_of ...

This reduces the usage of dev->type_data.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: get fs driver using container_of ...

This reduces the usage of dev->type_data.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: put fs devices on its own bus ...

By putting the fs devices/drivers on a bus on its own we can hook
into the bus remove function to cleanup the fs device. This way
we can unmount a device by simply unregistering the device which
is useful for for example USB mass storage devices. These can now
unregister the assoiated filesystems by unregistering their child
devices.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: remove fs devices list ...

We store the fs devices in a list only because we want to
check if the fs driver needs a backingstore or not. The
driver will bail out anyway if it needs a backingstore and
doesn't find one. So we can remove this check and thus remove
the list of fs devices.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: remove unused function fsdev_get_mountpoint ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: Store mtab path in allocated string ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: make locally used function get_mtab_entry_by_path static ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: Store mtab entries in list ...

To make the code a bit easier to read. Also, do not allow
to umount / when something else is mounted.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: implement flush function ...

Once we have caching in file functions we need a way to sync
the the underlying devices.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: remove unused field 'type' from struct fs_driver_d ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: replace broken dev_protect with protect_file function ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

get rid of device ids ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Get rid of DEVICE_TYPE_FS usage ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

- introduce ioctl call ...

- pass open/close/lseek through to drivers

add ls -c and -l