[XFS] Remove xfs_iflush_all and clean up xfs_finish_reclaim_all()

[XFS] Remove xfs_iflush_all and clean up xfs_finish_reclaim_all()

xfs_iflush_all() walks the m_inodes list to find inodes that need
reclaiming. We already have such a list - the m_del_inodes list. Replace
xfs_iflush_all() with a call to xfs_finish_reclaim_all() and clean up
xfs_finish_reclaim_all() to handle the different flush modes now needed.

Originally based on a patch from Christoph Hellwig.

Version 3 o rediff against new linux-2.6/xfs_sync.c code

Version 2 o revert xfs_syncsub() inode reclaim behaviour back to original

code o xfs_quiesce_fs() should use XFS_IFLUSH_DELWRI_ELSE_ASYNC, not

XFS_IFLUSH_ASYNC, to prevent change of behaviour.

SGI-PV: 988139

SGI-Modid: xfs-linux-melb:xfs-kern:32284a

Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>