1) Files weren't properly synced on filesystems other than UFS. In some
cases, this lead to lost data. Most likely would be noticed on NFS.
The fix is to make the VM page sync/object_clean general rather than
in each filesystem.
2) Mixing regular and mmaped file I/O on NFS was very broken. It caused
chunks of files to end up as zeroes rather than the intended contents.
The fix was to fix several race conditions and to kludge up the
"b_dirtyoff" and "b_dirtyend" that NFS relies upon - paying attention
to page modifications that occurred via the mmapping.
Reviewed by: David Greenman
Submitted by: John Dyson
require specific partitions be mentioned in the kernel config
file ("swap on foo" is now obsolete).
From Poul-Henning:
The visible effect is this:
As default, unless
options "NSWAPDEV=23"
is in your config, you will have four swap-devices.
You can swapon(2) any block device you feel like, it doesn't have
to be in the kernel config.
There is a performance/resource win available by getting the NSWAPDEV right
(but only if you have just one swap-device ??), but using that as default
would be too restrictive.
The invisible effect is that:
Swap-handling disappears from the $arch part of the kernel.
It gets a lot simpler (-145 lines) and cleaner.
Reviewed by: John Dyson, David Greenman
Submitted by: Poul-Henning Kamp, with minor changes by me.
1) Rewrote screwy code that uses an incore buffer without making it busy.
2) Use B_CACHE instead of B_DONE in cases where it is appropriate.
3) Minor code optimization.
This *might* fix kern/345 submitted by Heikki Suonsivu.
happen normally when there is heavy write activity to a file since the
vnode isn't locked (NFS plays fast and loose with vnode locks). This change
"fixes" PR#267.
VFCF_NETWORK (this FS goes over the net)
VFCF_READONLY (read-write mounts do not make any sense)
VFCF_SYNTHETIC (data in this FS is not real)
VFCF_LOOPBACK (this FS aliases something else)
cd9660 is readonly; nullfs, umapfs, and union are loopback; NFS is netowkr;
procfs, kernfs, and fdesc are synthetic.
in serious system instability. Changed a B_INVAL to a B_NOCACHE so that
buffer data is properly disposed of.
Submitted by: John Dyson, Rick Macklin, and ohki@gssm.otsuka.tsukuba.ac.jp
much higher filesystem I/O performance, and much better paging performance. It
represents the culmination of over 6 months of R&D.
The majority of the merged VM/cache work is by John Dyson.
The following highlights the most significant changes. Additionally, there are
(mostly minor) changes to the various filesystem modules (nfs, msdosfs, etc) to
support the new VM/buffer scheme.
vfs_bio.c:
Significant rewrite of most of vfs_bio to support the merged VM buffer cache
scheme. The scheme is almost fully compatible with the old filesystem
interface. Significant improvement in the number of opportunities for write
clustering.
vfs_cluster.c, vfs_subr.c
Upgrade and performance enhancements in vfs layer code to support merged
VM/buffer cache. Fixup of vfs_cluster to eliminate the bogus pagemove stuff.
vm_object.c:
Yet more improvements in the collapse code. Elimination of some windows that
can cause list corruption.
vm_pageout.c:
Fixed it, it really works better now. Somehow in 2.0, some "enhancements"
broke the code. This code has been reworked from the ground-up.
vm_fault.c, vm_page.c, pmap.c, vm_object.c
Support for small-block filesystems with merged VM/buffer cache scheme.
pmap.c vm_map.c
Dynamic kernel VM size, now we dont have to pre-allocate excessive numbers of
kernel PTs.
vm_glue.c
Much simpler and more effective swapping code. No more gratuitous swapping.
proc.h
Fixed the problem that the p_lock flag was not being cleared on a fork.
swap_pager.c, vnode_pager.c
Removal of old vfs_bio cruft to support the past pseudo-coherency. Now the
code doesn't need it anymore.
machdep.c
Changes to better support the parameter values for the merged VM/buffer cache
scheme.
machdep.c, kern_exec.c, vm_glue.c
Implemented a seperate submap for temporary exec string space and another one
to contain process upages. This eliminates all map fragmentation problems
that previously existed.
ffs_inode.c, ufs_inode.c, ufs_readwrite.c
Changes for merged VM/buffer cache. Add "bypass" support for sneaking in on
busy buffers.
Submitted by: John Dyson and David Greenman
If nd->swap_nblks is zero in nfs_mountroot(), then the system
comes up without initializing swapdev_vp to an actual vnode pointer.
The swap pager assumes a non-NULL value for swapdev_vp.
The fix is to try initializing local swap if no NFS swap space
is specified.
- Make a number of filesystems work again when they are statically compiled
(blush)
- FIFOs are no longer optional; ``options FIFO'' removed from distributed
config files.
machdep.c:
Changed printf's a little and call vfs_unmountall() if the sync was
successful.
cd9660_vfsops.c, ffs_vfsops.c, nfs_vfsops.c, lfs_vfsops.c:
Allow dismount of root FS. It is now disallowed at a higher level.
vfs_conf.c:
Removed unused rootfs global.
vfs_subr.c:
Added new routines vfs_unmountall and vfs_unmountroot. Filesystems
are now dismounted if the machine is properly rebooted.
ffs_vfsops.c:
Toggle clean bit at the appropriate places. Print warning if an
unclean FS is mounted.
ffs_vfsops.c, lfs_vfsops.c:
Fix bug in selecting proper flags for VOP_CLOSE().
vfs_syscalls.c:
Disallow dismounting root FS via umount syscall.
- Delete redundant declarations.
- Add -Wredundant-declarations to Makefile.i386 so they don't come back.
- Delete sloppy COMMON-style declarations of uninitialized data in
header files.
- Add a few prototypes.
- Clean up warnings resulting from the above.
NB: ioconf.c will still generate a redundant-declaration warning, which
is unavoidable unless somebody volunteers to make `config' smarter.
use it in NFS. This is required both for diskless support and for POSIX
compliance. Note: the support in NFS is only for the local node.
Submitted by: based on work originally done by Yuval Yurom
