CVS commit: src/sys

[Juergen Hannken-Illjes <hannken%netbsd.org@localhost>]

Module Name:    src
Committed By:   hannken
Date:           Tue Aug 12 10:14:38 UTC 2008

Modified Files:
        src/sys/dev: fss.c
        src/sys/ufs/ffs: ffs_extern.h ffs_snapshot.c ffs_vnops.c
        src/sys/ufs/ufs: ufs_readwrite.c ufs_vnops.c

Log Message:
Deny read/write access to snapshot vnodes.  We use fss(4) to read from
snapshots.  With this policy in place:

- Separate the snapshot vnode lock from the snapshot common lock.
  Snapshots no longer need recursive vnode locks.

- Use a mutex (si_snaplock) to serialize creation, deletion, reading and
  writing of snapshots.

- Move ffs_read() for snapshots into ffs_snapshot.c.

Reviewed by: Jason Thorpe <thorpej%netbsd.org@localhost>

While here change ffs_copyonwrite() to fail requests from pagedaemon that need
to copy-on-write.


To generate a diff of this commit:
cvs rdiff -r1.49 -r1.50 src/sys/dev/fss.c
cvs rdiff -r1.67 -r1.68 src/sys/ufs/ffs/ffs_extern.h
cvs rdiff -r1.73 -r1.74 src/sys/ufs/ffs/ffs_snapshot.c
cvs rdiff -r1.101 -r1.102 src/sys/ufs/ffs/ffs_vnops.c
cvs rdiff -r1.89 -r1.90 src/sys/ufs/ufs/ufs_readwrite.c
cvs rdiff -r1.167 -r1.168 src/sys/ufs/ufs/ufs_vnops.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.