squashed SDCardFS-import

fs: import Google's original sdcardfs

zero: updated defconfigs for new sdcardfs

namei: removed invalid check for sdcardfs from include

vfs: add d_canonical_path for stacked filesystem support

Inotify does not currently know when a filesystem
is acting as a wrapper around another fs. This means
that inotify watchers will miss any modifications to
the base file, as well as any made in a separate
stacked fs that points to the same file.
d_canonical_path solves this problem by allowing the fs
to map a dentry to a path in the lower fs. Inotify
can use it to find the appropriate place to watch to
be informed of all changes to a file.

Change-Id: I09563baffad1711a045e45c1bd0bd8713c2cc0b6
Signed-off-by: Daniel Rosenberg <drosen@google.com>

inotify: Fix erroneous update of bit count

Patch "vfs: add d_canonical_path for stacked filesystem support"
erroneously updated the ALL_INOTIFY_BITS count. This changes it back

Change-Id: Idb04edc736da276159d30f04c40cff9d6b1e070f

vfs: change d_canonical_path to take two paths

bug: 23904372
Change-Id: I4a686d64b6de37decf60019be1718e1d820193e6
Signed-off-by: Daniel Rosenberg <drosen@google.com>

fuse: Add support for d_canonical_path

Allows FUSE to report to inotify that it is acting
as a layered filesystem. The userspace component
returns a string representing the location of the
underlying file. If the string cannot be resolved
into a path, the top level path is returned instead.

bug: 23904372
Change-Id: Iabdca0bbedfbff59e9c820c58636a68ef9683d9f
Signed-off-by: Daniel Rosenberg <drosen@google.com>

mnt: Add filesystem private data to mount points

This starts to add private data associated directly
to mount points. The intent is to give filesystems
a sense of where they have come from, as a means of
letting a filesystem take different actions based on
this information.

Change-Id: Ie769d7b3bb2f5972afe05c1bf16cf88c91647ab2
Signed-off-by: Daniel Rosenberg <drosen@google.com>

vfs: Allow filesystems to access their private mount data

Now we pass the vfsmount when mounting and remounting.
This allows the filesystem to actually set up the mount
specific data, although we can't quite do anything with
it yet. show_options is expanded to include data that
lives with the mount.

To avoid changing existing filesystems, these have
been added as new vfs functions.

Change-Id: If80670bfad9f287abb8ac22457e1b034c9697097
Signed-off-by: Daniel Rosenberg <drosen@google.com>

vfs: Add permission2 for filesystems with per mount permissions

This allows filesystems to use their mount private data to
influence the permssions they return in permission2. It has
been separated into a new call to avoid disrupting current
permission users.

Change-Id: I9d416e3b8b6eca84ef3e336bd2af89ddd51df6ca
Signed-off-by: Daniel Rosenberg <drosen@google.com>

vfs: Add setattr2 for filesystems with per mount permissions

This allows filesystems to use their mount private data to
influence the permssions they use in setattr2. It has
been separated into a new call to avoid disrupting current
setattr users.

Change-Id: I19959038309284448f1b7f232d579674ef546385
Signed-off-by: Daniel Rosenberg <drosen@google.com>

ANDROID: vfs: Missed updating truncate to truncate2

Bug: 30954918
Change-Id: I8163d3f86dd7aadb2ab3fc11816754f331986f05
Signed-off-by: Daniel Rosenberg <drosen@google.com>

[readdir] introduce iterate_dir() and dir_context

iterate_dir(): new helper, replacing vfs_readdir().

struct dir_context: contains the readdir callback (and will get more stuff
in it), embedded into whatever data that callback wants to deal with;
eventually, we'll be passing it to ->readdir() replacement instead of
(data,filldir) pair.

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

[readdir] introduce ->iterate(), ctx->pos, dir_emit()

New method - ->iterate(file, ctx).  That's the replacement for ->readdir();
it takes callback from ctx->actor, uses ctx->pos instead of file->f_pos and
calls dir_emit(ctx, ...) instead of filldir(data, ...).  It does *not*
update file->f_pos (or look at it, for that matter); iterate_dir() does the
update.

Note that dir_emit() takes the offset from ctx->pos (and eventually
filldir_t will lose that argument).

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

[readdir] constify ->actor

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

fs: ecryptfs: readdir: constify actor

actor is a constant in dir_context struct and
because of that we run into following build failure:
----------
fs/ecryptfs/file.c: In function ‘ecryptfs_readdir’:
fs/ecryptfs/file.c:130:2: error: assignment of read-only member ‘actor’
make[2]: *** [fs/ecryptfs/file.o] Error 1
make[1]: *** [fs/ecryptfs] Error 2
make: *** [fs] Error 2
----------

This fix is based on commit: b2497fc3057a([readdir] constify ->actor)

Signed-off-by: Amit Pundir <amit.pundir@linaro.org>

sdcardfs: d_child and d_rcu do not longer share memory

zero: disabled Samsung's SCFS

ANDROID: sdcardfs: d_splice_alias can return error values

We must check that d_splice_alias was successful before using its
output.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Bug: 62390017
Change-Id: Ifda0a052fb3f67e35c635a4e5e907876c5400978

ANDROID: sdcardfs: remove dead function open_flags_to_access_mode()

smatch warns about the suspicious formatting in the last line of
open_flags_to_access_mode().  It turns out the only caller was deleted
over a year ago by "ANDROID: sdcardfs: Bring up to date with Android M
permissions:", so we can "fix" the function's formatting by deleting it.

Change-Id: Id85946f3eb01722eef35b1815f405a6fda3aa4ff
Signed-off-by: Greg Hackmann <ghackmann@google.com>

ANDROID: sdcardfs: use mount_nodev and fix a issue in sdcardfs_kill_sb

Use the VFS mount_nodev instead of customized mount_nodev_with_options
and fix generic_shutdown_super to kill_anon_super because of set_anon_super

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Change-Id: Ibe46647aa2ce49d79291aa9d0295e9625cfccd80

ANDROID: sdcardfs: Remove unnecessary lock

The mmap_sem lock does not appear to be protecting
anything, and has been removed in Samsung's more
recent versions of sdcardfs.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Change-Id: I76ff3e33002716b8384fc8be368028ed63dffe4e
Bug: 63785372

ANDROID: sdcardfs: override credential for ioctl to lower fs

Otherwise, lower_fs->ioctl() fails due to inode_owner_or_capable().

Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
Bug: 63260873
Change-Id: I623a6c7c5f8a3cbd7ec73ef89e18ddb093c43805

sdcardfs: make uid/gid with correct namespace

Change-Id: I0f04ad9e6d0cf5ab52469b89eea6a3421ff1f770

zero: disable SDP

Change-Id: Ic4d7b40f18b1f8c6e35745b45f40fc0c7518b26f