Add comments describing what the directions "up" and "down" mean and ref count
handling to the VFS mount following family of functions.

Signed-off-by: Valerie Aurora <vaurora@redhat.com> (Original author)
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

copy_tree() can theoretically fail in a case other than ENOMEM, but always
returns NULL which is interpreted by callers as -ENOMEM.  Change it to return
an explicit error.

Also change clone_mnt() for consistency and because union mounts will add new
error cases.

Thanks to Andreas Gruenbacher <agruen@suse.de> for a bug fix.
[AV: folded braino fix by Dan Carpenter]

Original-author: Valerie Aurora <vaurora@redhat.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Cc: Valerie Aurora <valerie.aurora@gmail.com>
Cc: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Make the chown() and lchown() syscalls jump to the fchownat() syscall with the
appropriate extra arguments.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

we want to take it out of mark_files_ro() reach *before* we start
checking if we ought to drop write access.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

mnt_drop_write_file() is safe under any lock
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: Djalal Harouni <tixxdz@opendz.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Add a helper that abstracts out the jump to an already parsed struct path
from ->follow_link operation from procfs.  Not only does this clean up
the code by moving the two sides of this game into a single helper, but
it also prepares for making struct nameidata private to namei.c
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Currently the non-nd_set_link based versions of ->follow_link are expected
to do a path_put(&nd->path) on failure.  This calling convention is unexpected,
undocumented and doesn't match what the nd_set_link-based instances do.

Move the path_put out of the only non-nd_set_link based ->follow_link
instance into the caller.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

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

It, debugfs_create_dir() and debugfs_create_link() use the common helper
now.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

same as for nfs et.al.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

a) ->d_iput() is wrong here - what we do to inode is completely usual, it's
dentry->d_fsdata that we want to drop.  Just use ->d_release().

b) switch to ->s_d_op - no need to play with d_set_d_op()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

all callers want the same thing, actually - a kinda-sorta analog of
kern_path_create().  I.e. they want parent vfsmount/dentry (with
->i_mutex held, to make sure the child dentry is still their child)
+ the child dentry.

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

Since commit 197e37d9, the banner comment on lookup_open() no longer matches
what the function returns.  It used to return a struct file pointer or NULL and
now it returns an integer and is passed the struct file pointer it is to use
amongst its arguments.  Update the comment to reflect this.

Also add a banner comment to atomic_open().
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

all we want is a boolean flag, same as the method gets now
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

boolean "does it have to be exclusive?" flag is passed instead;
Local filesystem should just ignore it - the object is guaranteed
not to be there yet.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

Just the flags; only NFS cares even about that, but there are
legitimate uses for such argument.  And getting rid of that
completely would require splitting ->lookup() into a couple
of methods (at least), so let's leave that alone for now...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

since the method wrapped by it doesn't need that anymore...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Just the lookup flags.  Die, bastard, die...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

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

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

... and get rid of a couple of arguments and a pointless reassignment
in finish_open() case.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

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

namely, 1 ;-)  That's what we want to return from ->atomic_open()
instances after finish_no_open().
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Same conventions as for ->atomic_open().  Trimmed the
forest of labels a bit, while we are at it...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Just pass struct file *.  Methods are happier that way...
There's no need to return struct file * from finish_open() now,
so let it return int.  Next: saner prototypes for parts in
namei.c
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

->filp->f_path is there for purpose...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Change of calling conventions:
old		new
NULL		1
file		0
ERR_PTR(-ve)	-ve

Caller *knows* that struct file *; no need to return it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

make put_filp() conditional on flag set by finish_open()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and let finish_open() report having opened the file via that sucker.
Next step: don't modify od->filp at all.

[AV: FILE_CREATE was already used by cifs; Miklos' fix folded]
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Perform open_check_o_direct() in a common place in do_last after opening the
file.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Move the lookup retry logic to the bottom of the function to make the normal
case simpler to read.
Reported-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Consistently use bool for boolean values in do_last().
Reported-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Reported-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>