fs: dentry cache implementation ...

This adds the Linux dentry cache implementation to barebox.

Until now every filesystem driver resolves the full path to a file for
itself. This leads to code duplication and is error prone since
resolving paths is a complicated task. Also it can narrow down the
lookup performance since barebox only knows ASCII paths and has no way
of caching lookups.

With this patch we get the Linux dcache implementation. The path
resolving code from fs/namei.c is nearly taken as-is, minus the RCU
and locking code. Dcaching is made simple as of now: We simply cache
everything and never release any dentries. Although we do reference
counting for inodes and dentries it is effectively not used yet.
We never free anything until a fs is unmounted in which case we free
everything no matter if references are taken or not.

This patch also contains a wrapper in fs/legacy.c to support
filesystems with the old API.

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

fs: remove now unused function can_lseek_backward() ...

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

fs: implement is_tftp_fs() ...

Some commands need files in which they can lseek backwards which
is particularly not possible on TFTP. Instead of hiding this
behind can_lseek_backward() create a function for it which tests
if the file is on TFTP directly rather than using different
lseek operations.

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

fs: Introduce devpath_to_name() ...

Add a simple function to simplify the task of accepting both full path
in "/dev" and just device name as a parameter.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: Fix can_lseek_backward() ...

To quote corresponding man page:

"... Upon successful completion, lseek() returns the resulting offset
location as measured in bytes from the beginning of the file."

Which for lseek(fd, 0, SEEK_SET) would be 0, so returning 'ret' as
final step of the function would mean it'd never return anything but 0
as well. Change the code to explicitly return '1' to fix the problem.

Fixes: 7c3f8d366 ("uimage: fix: add can_lseek_backward and use in uimage_open")
Cc: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

uimage: fix: add can_lseek_backward and use in uimage_open ...

Since commit ce0cc7fe we support forward seek on tftpfs. This feature
breaks the condition to check rather we open an uimage over tftp. Since
backward seeking is the problem here, we add the function
can_lseek_backward and check for it instead of the simple lseek.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Merge branch 'for-next/misc'

fs: add cdev_create_loop and cdev_remove_loop for loop mount option ...

Allow to create a loopback cdev from a file.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Fixed up with:

fs: Makefile: Add parseopt to all builds

parseopt.h was included to fs.c with commit 9248b, but parseopt.o has a
dependency to CONFIG_FS_NFS.

Moved parseopt.o to the default build to eliminate build failures.

Signed-off-by: Daniel Schultz <d.schultz@phytec.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: Implement links to directories ...

So far links can only point to files. Implement links to
directories. With this all kinds of links are supported:

- relative links
- absolute links
- links including ".."
- link loops (are detected, return -EMLINK)

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

Merge branch 'for-next/include-cleanup'

fix erasing/protecting flashes with unspecified size ...

fixes: 81737c1 mtd: Fix erasing of devices >4GiB

Several places erased a complete flash partition passing ~0 as count to
erase(). With the above commit count to erase was changed from an unsigned
type to a signed type, so the (count > f->size - offset) check in
erase() no longer triggers and the ~0 count is no longer adjusted to the whole
device size. Among other things this results in saveenv failures on NOR
flashes.
This patch fixes this by introducing an explicit macro for erasing the
whole device which is tested for in erase(). All other negative values
are rejected.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reported-by: Giorgio <giorgio.nicole@arcor.de>

fs: move libc function prototypes to their correct locations ...

This moves the function prototypes in include/fs.h which also exist
in the libc to the locations they would have in libc.

With this it becomes easier to share code between barebox and userspace
since the usual libc include files will exist. Also users of the libc
functions no longer have to include the barebox internal fs.h header.

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

move unlink_recursive declaration to libfile.h ...

unlink_recursive is a file utility function, so move the prototype to
libfile.h

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

move make_directory declaration to libfile.h ...

As a utility function for file handling make_directory() is well
suited for libfile. Move it there.

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

fs: umount based on device path and mount path ...

umount on Linux can be used on a mount pathes and device pathes. This
patch adds this functionality to barebox.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>

fs: Add for_each_fs_device_safe() ...

We need to be able to umount specific filesystems while iterating all of
them. This helper gives us a safe macro to do so.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>

mtd: Fix erasing of devices >4GiB ...

When a device >4GiB is erased, not only the offset can be bigger
than 4GiB, but also the size. This happens with the simplest command
to erase a device: erase /dev/nand0. Make the size argument a 64bit
type to make this work.

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

fs: use linux/fs.h for file system related definitions ...

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: Add device parameter for Linux root= option ...

When registering a filesystem device add a device parameter suitable
for the Linux root= option to boot from exactly this filesystem. Currently
the fs layer sets this parameter to the root=PARTUUID= mechanism if a
partuuid is available. Other filesystems like NFS and UBIFS which do
not have a PARTUUID can overwrite this.

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

Merge branch 'for-next/fs'

fs: rename inode member of struct filep to priv ...

Because that's what it is. 'inode' will become confusing
once we support real inodes.

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

fs: make "offset" parameter of erase() and protect() 64 bit safe ...

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: implement fstat ...

fstat is useful to get information about an already opened file. Add
it to barebox.

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

fs: Store the path in struct filep ...

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

fs: store pointer to fsdev instead of dev in struct filep ...

The struct device_d * in struct filep is never of interest, instead
it is always converted to a struct fs_device_d *, so simplify the code
by storing the struct fs_device_d * directly.

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

move file helper functions to separate file ...

We have our file helper functions in several places. Move them
all to lib/libfile.c.
With this we no longer have file helpers in fs/fs.c which contains
the core fs functions and no functions in lib/libbb.c which are
not from busybox.

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

mount: support filesystem options passed via -o ...

Similar to mount(8) the barebox command mount now supports passing a string
to the file system driver via -o.

This is used in the next commit to let the user specify port numbers for
nfs mounts.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

fs: Add function to get cdev by mountpath ...

This is useful to know for the bootloader spec implementation.

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

fs: add cdev mount helpers ...

Introduce helpers to iterate over cdevs and mount them to a known
path.

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

mount: implement -v option to print available filesystems ...

It's useful to know which filesystems a barebox binary supports.
Add a -v option to the mount command to find it out.

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