This patch adds f2fs encryption config.

This patch integrates:

"ext4 crypto: require CONFIG_CRYPTO_CTR if ext4 encryption is enabled

On arm64 this is apparently needed for CTS mode to function correctly.
Otherwise attempts to use CTS return ENOENT."
Signed-off-by: NMichael Halcrow <mhalcrow@google.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

The f2fs has been shipped on many smartphone devices during a couple of years.
So, it is worth to relocate Kconfig into main page from misc filesystems for
developers to choose it more easily.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch adds:
 o initial trace.c and trace.h with skeleton functions
 o Kconfig and Makefile to activate this feature
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Fix typo and some grammatical errors.

The words "filesystem" and "readahead" are being used without the space treewide.
Signed-off-by: NPark Ju Hyung <qkrwngud825@gmail.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This config will support an option to remove so many BUG_ONs that degrade
the performance potentially.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch adds the support of security labels for f2fs, which will be used
by Linus Security Models (LSMs).

Quote from http://en.wikipedia.org/wiki/Linux_Security_Modules:
"Linux Security Modules (LSM) is a framework that allows the Linux kernel to
support a variety of computer security models while avoiding favoritism toward
any single security implementation. The framework is licensed under the terms of
the GNU General Public License and is standard part of the Linux kernel since
Linux 2.6. AppArmor, SELinux, Smack and TOMOYO Linux are the currently accepted
modules in the official kernel.".
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

There exist two build failures reported by Randy Dunlap as follows.

(on i386)
 a. (config-r8857)
	ERROR: "f2fs_xattr_advise_handler" [fs/f2fs/f2fs.ko] undefined!

Key configs in (config-r8857) are as follows.
 CONFIG_F2FS_FS=m
 # CONFIG_F2FS_STAT_FS is not set
 CONFIG_F2FS_FS_XATTR=y
 # CONFIG_F2FS_FS_POSIX_ACL is not set

The error was occurred due to the function location that we made a mistake.
Recently we added a new functionality for users to indicate cold files
explicitly through xattr operations (i.e., f2fs_xattr_advise_handler).

This handler should have been added in xattr.c instead of acl.c in order
to avoid an undefined operation like in this case where XATTR is set and
ACL is not set.

 b. (config-r8855)
	fs/f2fs/file.c: In function 'f2fs_vm_page_mkwrite':
	fs/f2fs/file.c:97:2: error: implicit declaration of function
	'block_page_mkwrite_return'

Key config in (config-r8855) is CONFIG_BLOCK.

Obviously, f2fs works on top of the block device so that we should consider
carefully a sort of config dependencies.

The reason why this error was occurred was that f2fs_vm_page_mkwrite() calls
block_page_mkwrite_return() which is enalbed only if CONFIG_BLOCK is set.
Reported-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>
Acked-by: NRandy Dunlap <rdunlap@xenotime.net>

This adds Makefile and Kconfig for f2fs, and updates Makefile and Kconfig files
in the fs directory.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>