tmpfs: support SEEK_DATA and SEEK_HOLE (reprise)

Revert 3.5's commit f21f8062201f ("tmpfs: revert SEEK_DATA and
SEEK_HOLE") to reinstate 4fb5ef089b28 ("tmpfs: support SEEK_DATA and
SEEK_HOLE"), with the intervening additional arg to
generic_file_llseek_size().

In 3.8, ext4 is expected to join btrfs, ocfs2 and xfs with proper
SEEK_DATA and SEEK_HOLE support; and a good case has now been made for
it on tmpfs, so let's join the party.

It's quite easy for tmpfs to scan the radix_tree to support llseek's new
SEEK_DATA and SEEK_HOLE options: so add them while the minutiae are
still on my mind (in particular, the !PageUptodate-ness of pages
fallocated but still unwritten).

[[email protected]: fix warning with CONFIG_TMPFS=n]
Signed-off-by: Hugh Dickins <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Jaegeuk Hanse <[email protected]>
Cc: "Theodore Ts'o" <[email protected]>
Cc: Zheng Liu <[email protected]>
Cc: Jeff liu <[email protected]>
Cc: Paul Eggert <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Josef Bacik <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Andreas Dilger <[email protected]>
Cc: Marco Stornelli <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Sunil Mushran <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions