freebsd-src/sys/fs/unionfs
KATO Takenori 81bca6ddae Clustered read and write are switched at mount-option level.
1. Clustered I/O is switched by the MNT_NOCLUSTERR and MNT_NOCLUSTERW
   bits of the mnt_flag.  The sysctl variables, vfs.foo.doclusterread
   and vfs.foo.doclusterwrite are deleted.  Only mount option can
   control clustered I/O from userland.
2. When foofs_mount mounts block device, foofs_mount checks D_CLUSTERR
   and D_CLUSTERW bits of the d_flags member in the block device switch
   table.  If D_NOCLUSTERR / D_NOCLUSTERW are set, MNT_NOCLUSTERR /
   MNT_NOCLUSTERW bits will be set.  In this case, MNT_NOCLUSTERR and
   MNT_NOCLUSTERW cannot be cleared from userland.
3. Vnode driver disables both clustered read and write.
4. Union filesystem disables clutered write.

Reviewed by:	bde
1997-09-27 13:40:20 +00:00
..
union_subr.c Change the M_NAMEI allocations to use the zone allocator. This change 1997-09-21 04:24:27 +00:00
union_vfsops.c Clustered read and write are switched at mount-option level. 1997-09-27 13:40:20 +00:00
union_vnops.c Convert select -> poll. 1997-09-14 02:58:12 +00:00
union.h