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: allow to mount on subdirectories ...

Since get_mtab_entry_by_path() is a bit more flexible now
we no longer have to force the user to mount on the root
directory only. Instead, we can allow to mount on subdirectories
aswell. Nested mounts are still not possible though.

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 only once used variable ...

dev is used only once, so make the code a tiny bit simpler by
not using an extra variable but dereference it when needed directly.

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

fs: simplify get_mtab_entry_by_path ...

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>

mount: Fix the printing of device name ...

Mount without argument always print a "none" as device name mounted
because entry->parent_device is always NULL.

The problem is the mount function in fs/fs.c. parent_device is
initialized to NULL and never updated. With this patch,
parent_device is set with the mounted device name.

Moreover, the mount function has been modified to print the device
name plus device id using the dev_name function.

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: read: do not call read op when count is 0 ...

Some ops do not handle read with count = 0 correctly. They do
not have to if this is catched in the upper layer.

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

fix bug introduced with fixing path_check_prereq() ...

This fixes a bug introduced with:

commit 74c3632
Author: Antony Pavlov <antonynpavlov@gmail.com>
Date:   Tue Oct 18 13:48:44 2011 +0400

    fs: fix path_check_prereq()

    This patch makes impossible the situations than path_check_prereq() can make
    'return 0' without changing errno.

    Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
    Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

path_check_prereq is supposed to return 0 when a file does
not exist and S_UB_DOES_NOT_EXIST is given. stat() changes
errno, so we have to set errno back to 0 before returning.

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

fs: fix chdir() ...

chdir() allocates memory using mormalise_path(). But if path_check_prereq()
returns error than memory isn't freed.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: fix path_check_prereq() ...

This patch makes impossible the situations than path_check_prereq() can make
'return 0' without changing errno.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: switch to resource ...

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

mem_read/write: use resources ...

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

fs mount: fix error handling ...

If we register a device we have to unregister it later when
the driver did not accept the device. Also, do not forget to
free the backingstore string.

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

fs: use safe_strncpy instead of sprintf ...

This is safe against string overflows.

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: errno should be set correctly before the end of functions ...

Otherwise we end up with errno not being set correctly
if a filesystem driver uses the standard open/close/read/write
functions to access its backing store.

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

fs: fix multiple mount of the same fstype ...

We need to assign a new device id if we want to register
a fs with the same type of an already registered fstype.

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

fs: Fix bug found by sparse. ...

Patch fix following sparse warning:
fs/fs.c:757:28: warning: dubious: !x & y

Signed-off-by: Marek Belisko <marek.belisko@open-nandra.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: add basic sanity check before accessing the files array ...

This patch adds some basic file descriptor sanity checks to the file access
routines. Check whether the given file descriptor is in the files array range,
and whether the file entry is valid.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
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>

fs: write: fix writing on devices ...

We can't truncate device files. Make sure that if we want to
write beyond the device that the bytes that still fit into the
device get written.

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 cdev ...

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