Cachefiles should perform fs modifications (eg. vfs_unlink()) on the top layer
only and should not attempt to alter the lower layer.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Fix inconsistent use of file_inode() vs file->f_path.dentry->d_inode.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Make pathwalk use d_is_reg() rather than S_ISREG() to determine whether to
honour O_TRUNC.  Since this occurs after complete_walk(), the dentry type
field cannot change and the inode pointer cannot change as we hold a ref on
the dentry, so this should be safe.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Fix up debugfs to use d_is_dir(dentry) in place of
S_ISDIR(dentry->d_inode->i_mode).
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Where we have:

    	if (!dentry->d_inode || d_is_negative(dentry)) {

type constructions in pathwalk we should be able to eliminate the check of
d_inode and rely solely on the result of d_is_negative() or d_is_positive().

What we do have to take care to do is to read d_inode after calling a
d_is_xxx() typecheck function to get the barriering right.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Don't use d_inode as a variable name as it now masks a function name.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Impose ordering on accesses of d_inode and d_flags to avoid the need to do
this:

	if (!dentry->d_inode || d_is_negative(dentry)) {

when this:

	if (d_is_negative(dentry)) {

should suffice.

This check is especially problematic if a dentry can have its type field set
to something other than DENTRY_MISS_TYPE when d_inode is NULL (as in
unionmount).

What we really need to do is stick a write barrier between setting d_inode and
setting d_flags and a read barrier between reading d_flags and reading
d_inode.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

we can do that now - all we need is to clear IOCB_DIRECT from ->ki_flags in
"can't do dio" case.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... avoiding write_iter/fcntl races.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... returning -E... upon error and amount of data left in iter after
(possible) truncation upon success.  Note, that normal case gives
a non-zero (positive) return value, so any tests for != 0 _must_ be
updated.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Conflicts:
	fs/ext4/file.c

	Alignment checks for dio depend upon the range truncation done by
generic_write_checks().  They can be done as soon as we got ocfs2_rw_lock()
and that actually makes ocfs2_prepare_inode_for_write() simpler.

	The only thing to watch out for is restoring the original count
in "unlock and redo without dio" case.  Position doesn't need to be
restored, since we change it only in O_APPEND case and in that case it
will be reassigned anyway.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

it's &iocb->ki_pos; no need to obfuscate.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

it's easier to do generic_write_checks() first
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

already done by caller.  We used to call __fuse_direct_write(), which
called generic_write_checks(); now the former got expanded, bringing
the latter to the surface.  It used to be called all along and calling
it from there had been wrong all along...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

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

all remaining callers are passing 0; some just obscure that fact.
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>

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

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

That allows ->write_iter() instances much more convenient life wrt
iocb->ki_pos (and fixes several filesystems with borderline POSIX
violations when zero-length write succeeds and changes the current
position).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Now that no one is using rw, remove it completely.
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The rw parameter to direct_IO is redundant with iov_iter->type, and
treated slightly differently just about everywhere it's used: some users
do rw & WRITE, and others do rw == WRITE where they should be doing a
bitwise check. Simplify this with the new iov_iter_rw() helper, which
always returns either READ or WRITE.
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

And use iov_iter_rw() instead.
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Most filesystems call through to these at some point, so we'll start
here.
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

no remaining users
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

all remaining instances of aio_{read,write} (all 4 of them) have explicit
->read and ->write resp.; do_sync_read/do_sync_write is never called by
__vfs_read/__vfs_write anymore and no other users had been left.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

store reference to iter instead of that to iovec
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

we just change the calling conventions here; more work to follow.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

All places outside of core VFS that checked ->read and ->write for being NULL or
called the methods directly are gone now, so NULL {read,write} with non-NULL
{read,write}_iter will do the right thing in all cases.
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>

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

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

... and fix the case when the area we are asked to read crosses
a hugepage boundary
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and request the same from the local cache - all filesystems with
anything usable for that support those already.
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>