MFC r287361:

MFC r287361:
Handle excess of D_NEWBLK in the same way as excess of D_INODEDEP and
D_DIRREM, by scheduling ast to flush dependencies.

For 32bit arches, reduce the total amount of allowed dependencies by two.

MFC r287479:
Declare the writes around the call to VFS_SYNC() in
softdep_ast_cleanup_proc().

MFC r287483:
Do not consume extra reference.

git-svn-id: svn://svn.freebsd.org/base/stable/10@287845 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f