Our f2fs_acl_create is copied and modified from posix_acl_create to avoid
deadlock bug when inline_dentry feature is enabled.

Now, we got reference leaks in posix_acl_create, and this has been fixed in
commit fed0b588 ("posix_acl: fix reference leaks in posix_acl_create")
by Omar Sandoval.
https://lkml.org/lkml/2015/2/9/5

Let's fix this issue in f2fs_acl_create too.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Reviewed-by: NChangman Lee <cm224.lee@ssamsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Introduced by a6dda0e6
"f2fs: use generic posix ACL infrastructure".

When testing default acl, gets in recent kernel (3.19.0-rc5),
user::rwx
group::r-x
other::r-x
default:user::rwx
default:group::r-x
default:group:root:rwx
default:mask::rwx
default:other::r-x

]# getfacl testdir/
user::rwx
group::rwx
                // missing an acl "group:root:rwx" inherited from parent
other::r-x
default:user::rwx
default:group::r-x
default:group:root:rwx
default:mask::rwx
default:other::r-x
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

The __f2fs_add_link is covered by cp_rwsem all the time.
This calls init_inode_metadata, which conducts some acl operations including
memory allocation with GFP_KERNEL previously.
But, under memory pressure, f2fs_write_data_page can be called, which also
grabs cp_rwsem too.

In this case, this incurs a deadlock pointed by Chao.
Thread #1        Thread #2
 down_read
                 down_write
  down_read
 -> here down_read should wait forever.
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Use clear_inode_flag to replace the redundant cond_clear_inode_flag.
Signed-off-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Previously, init_inode_metadata does not hold any parent directory's inode
page. So, f2fs_init_acl can grab its parent inode page without any problem.
But, when we use inline_dentry, that page is grabbed during f2fs_add_link,
so that we can fall into deadlock condition like below.

INFO: task mknod:11006 blocked for more than 120 seconds.
      Tainted: G           OE  3.17.0-rc1+ #13
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mknod           D ffff88003fc94580     0 11006  11004 0x00000000
 ffff880007717b10 0000000000000002 ffff88003c323220 ffff880007717fd8
 0000000000014580 0000000000014580 ffff88003daecb30 ffff88003c323220
 ffff88003fc94e80 ffff88003ffbb4e8 ffff880007717ba0 0000000000000002
Call Trace:
 [<ffffffff8173dc40>] ? bit_wait+0x50/0x50
 [<ffffffff8173d4cd>] io_schedule+0x9d/0x130
 [<ffffffff8173dc6c>] bit_wait_io+0x2c/0x50
 [<ffffffff8173da3b>] __wait_on_bit_lock+0x4b/0xb0
 [<ffffffff811640a7>] __lock_page+0x67/0x70
 [<ffffffff810acf50>] ? autoremove_wake_function+0x40/0x40
 [<ffffffff811652cc>] pagecache_get_page+0x14c/0x1e0
 [<ffffffffa029afa9>] get_node_page+0x59/0x130 [f2fs]
 [<ffffffffa02a63ad>] read_all_xattrs+0x24d/0x430 [f2fs]
 [<ffffffffa02a6ca2>] f2fs_getxattr+0x52/0xe0 [f2fs]
 [<ffffffffa02a7481>] f2fs_get_acl+0x41/0x2d0 [f2fs]
 [<ffffffff8122d847>] get_acl+0x47/0x70
 [<ffffffff8122db5a>] posix_acl_create+0x5a/0x150
 [<ffffffffa02a7759>] f2fs_init_acl+0x29/0xcb [f2fs]
 [<ffffffffa0286a8d>] init_inode_metadata+0x5d/0x340 [f2fs]
 [<ffffffffa029253a>] f2fs_add_inline_entry+0x12a/0x2e0 [f2fs]
 [<ffffffffa0286ea5>] __f2fs_add_link+0x45/0x4a0 [f2fs]
 [<ffffffffa028b5b6>] ? f2fs_new_inode+0x146/0x220 [f2fs]
 [<ffffffffa028b816>] f2fs_mknod+0x86/0xf0 [f2fs]
 [<ffffffff811e3ec1>] vfs_mknod+0xe1/0x160
 [<ffffffff811e4b26>] SyS_mknod+0x1f6/0x200
 [<ffffffff81741d7f>] tracesys+0xe1/0xe6
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

kernel side(xx_init_acl), the acl is get/cloned from the parent dir's,
which is credible. So remove the redundant validation check of acl
here.
Signed-off-by: NGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

This patch passes the "flags" field to the low level setxattr functions
to use XATTR_REPLACE in the following patches.
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

Before setting the acl, call posix_acl_valid() to check if it is
valid or not.
Signed-off-by: Nzhangzhen <zhenzhang.zhang@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch should resolve the following possible bug.

RECLAIM_FS-ON-W at:
 mark_held_locks+0xb9/0x140
 lockdep_trace_alloc+0x85/0xf0
 __kmalloc+0x53/0x1d0
 read_all_xattrs+0x3d1/0x3f0 [f2fs]
 f2fs_getxattr+0x4f/0x100 [f2fs]
 f2fs_get_acl+0x4c/0x290 [f2fs]
 get_acl+0x4f/0x80
 posix_acl_create+0x72/0x180
 f2fs_init_acl+0x29/0xcc [f2fs]
 __f2fs_add_link+0x259/0x710 [f2fs]
 f2fs_create+0xad/0x1c0 [f2fs]
 vfs_create+0xed/0x150
 do_last+0xd36/0xed0
 path_openat+0xc5/0x680
 do_filp_open+0x43/0xa0
 do_sys_open+0x13c/0x230
 SyS_creat+0x1e/0x20
 system_call_fastpath+0x16/0x1b
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

f2fs has some weird mode bit handling, so still using the old
chmod code for now.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Rename the current posix_acl_created to __posix_acl_create and add
a fully featured helper to set up the ACLs on file creation that
uses get_acl().
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Rename the current posix_acl_chmod to __posix_acl_chmod and add
a fully featured ACL chmod helper that uses the ->set_acl inode
operation.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The deadlock is found through the following scenario.

sys_mkdir()
 -> f2fs_add_link()
  -> __f2fs_add_link()
   -> init_inode_metadata()
     : lock_page(inode);
    -> f2fs_init_acl()
     -> f2fs_set_acl()
      -> f2fs_setxattr(..., NULL)
       : This NULL page incurs a deadlock at update_inode_page().

So, likewise f2fs_init_security(), this patch adds a parameter to transfer the
locked inode page to f2fs_setxattr().

Found by Linux File System Verification project (linuxtesting.org).
Reported-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This patch cleans up a couple of acl codes.
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>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch resolves Coverity #751303:

>>> CID 753103: Explicit null dereferenced (FORWARD_NULL) Passing null
>>> pointer "value" to function "f2fs_acl_from_disk(char const *, size_t)",
	which dereferences it.

[Error path]
- value = NULL;
- retval = 0 by f2fs_getxattr();
- f2fs_acl_from_disk(value:NULL, ...);
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

With user namespaces enabled building f2fs fails with:

 CC      fs/f2fs/acl.o
fs/f2fs/acl.c: In function ‘f2fs_acl_from_disk’:
fs/f2fs/acl.c:85:21: error: ‘struct posix_acl_entry’ has no member named ‘e_id’
make[2]: *** [fs/f2fs/acl.o] Error 1
make[2]: Target `__build' not remade because of errors.

e_id is a backwards compatibility field only used for file systems
that haven't been converted to use kuids and kgids.  When the posix
acl tag field is neither ACL_USER nor ACL_GROUP assigning e_id is
unnecessary.  Remove the assignment so f2fs will build with user
namespaces enabled.

Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Amit Sahrawat <a.sahrawat@samsung.com>
Acked-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.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>

As pointed out by Randy Dunlap, this patch removes all usage of "/**" for comment
blocks. Instead, just use "/*".
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

This implements xattr and acl functionalities.

- F2FS uses a node page to contain use extended attributes.
Signed-off-by: NChangman Lee <cm224.lee@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>