block: remove READ_META and WRITE_META

Replace all occurnanced of the undocumented READ_META with READ | REQ_META
and remove the unused WRITE_META define.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Conflicts:
	fs/ext3/inode.c
	fs/ext3/namei.c
	fs/ext4/inode.c
	fs/ext4/namei.c
	fs/gfs2/quota.c
fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers

Btrfs needs to be able to control how filemap_write_and_wait_range() is called
in fsync to make it less of a painful operation, so push down taking i_mutex and
the calling of filemap_write_and_wait() down into the ->fsync() handlers.  Some
file systems can drop taking the i_mutex altogether it seems, like ext3 and
ocfs2.  For correctness sake I just pushed everything down in all cases to make
sure that we keep the current behavior the same for everybody, and then each
individual fs maintainer can make up their mind about what to do from there.
Thanks,

Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Conflicts:
	Documentation/filesystems/porting

Change-Id: I7697244cce355e6d443a39c5133a5c94f02e199b

Conflicts:
	fs/sync.c
fix commit

Conflicts:
	arch/arm/boot/zImage
Revert "f2fs: fix recursive lock by f2fs_setxattr"

This reverts commit 74a58694413fb1ce1e3b1b6c33964a4877973d95.