Date: Thu, 16 Sep 1999 23:10:28 -0700 (PDT) From: Matt Dillon <dillon@FreeBSD.org> To: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/miscfs/specfs spec_vnops.c src/sys/sys vnode.h src/sys/kern vfs_subr.c Message-ID: <199909170610.XAA56084@freefall.freebsd.org>
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dillon 1999/09/16 23:10:28 PDT
Modified files:
sys/miscfs/specfs spec_vnops.c
sys/sys vnode.h
sys/kern vfs_subr.c
Log:
Add vfs.enable_userblk_io sysctl to control whether user reads and writes
to buffered block devices are allowed. The default is to be backwards
compatible, i.e. reads and writes are allowed.
The idea is for a larger crowd to start running with this disabled and
see what problems, if any, crop up, and then to change the default to
off and see if any problems crop up in the next 6 months prior to
potentially removing support entirely. There are still a few people,
Julian and myself included, who believe the buffered block device
access from usermode to be useful.
Remove use of vnode->v_lastr from buffered block device I/O in
preparation for removal of vnode->v_lastr field, replacing it with
the already existing seqcount metric to detect sequential operation.
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
Revision Changes Path
1.108 +10 -5 src/sys/miscfs/specfs/spec_vnops.c
1.100 +2 -1 src/sys/sys/vnode.h
1.225 +4 -1 src/sys/kern/vfs_subr.c
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