This code will be turned on with the TWO options
DEVFS and SLICE. (see LINT)
Two labels PRE_DEVFS_SLICE and POST_DEVFS_SLICE will deliniate these changes.
/dev will be automatically mounted by init (thanks phk)
on bootup. See /sys/dev/slice/slice.4 for more info.
All code should act the same without these options enabled.
Mike Smith, Poul Henning Kamp, Soeren, and a few dozen others
This code does not support the following:
bad144 handling.
Persistance. (My head is still hurting from the last time we discussed this)
ATAPI flopies are not handled by the SLICE code yet.
When this code is running, all major numbers are arbitrary and COULD
be dynamically assigned. (this is not done, for POLA only)
Minor numbers for disk slices ARE arbitray and dynamically assigned.
"time" wasn't a atomic variable, so splfoo() protection were needed
around any access to it, unless you just wanted the seconds part.
Most uses of time.tv_sec now uses the new variable time_second instead.
gettime() changed to getmicrotime(0.
Remove a couple of unneeded splfoo() protections, the new getmicrotime()
is atomic, (until Bruce sets a breakpoint in it).
A couple of places needed random data, so use read_random() instead
of mucking about with time which isn't random.
Add a new nfs_curusec() function.
Mark a couple of bogosities involving the now disappeard time variable.
Update ffs_update() to avoid the weird "== &time" checks, by fixing the
one remaining call that passwd &time as args.
Change profiling in ncr.c to use ticks instead of time. Resolution is
the same.
Add new function "tvtohz()" to avoid the bogus "splfoo(), add time, call
hzto() which subtracts time" sequences.
Reviewed by: bde
softdep mode could only be activated on the initial mount of a filesystem
and then only if it was a read-write mount. A 'mount -r' (as done in the
rootfs mount) followed by a 'mount -u' to convert to read-write didn't
start softdep mode.
They are atomic, but return in essence what is in the "time" variable.
gettime() is now a macro front for getmicrotime().
Various patches to use the two new functions instead of the various
hacks used in their absence.
Some puntuation and grammer patches from Bruce.
A couple of XXX comments.
problems. Tor Egge and others have helped with various VM bugs
lately, but don't blame him -- blame me!!!
pmap.c:
1) Create an object for kernel page table allocations. This
fixes a bogus allocation method previously used for such, by
grabbing pages from the kernel object, using bogus pindexes.
(This was a code cleanup, and perhaps a minor system stability
issue.)
pmap.c:
2) Pre-set the modify and accessed bits when prudent. This will
decrease bus traffic under certain circumstances.
vfs_bio.c, vfs_cluster.c:
3) Rather than calculating the beginning virtual byte offset
multiple times, stick the offset into the buffer header, so
that the calculated offset can be reused. (Long long multiplies
are often expensive, and this is a probably unmeasurable performance
improvement, and code cleanup.)
vfs_bio.c:
4) Handle write recursion more intelligently (but not perfectly) so
that it is less likely to cause a system panic, and is also
much more robust.
vfs_bio.c:
5) getblk incorrectly wrote out blocks that are incorrectly sized.
The problem is fixed, and writes blocks out ONLY when B_DELWRI
is true.
vfs_bio.c:
6) Check that already constituted buffers have fully valid pages. If
not, then make sure that the B_CACHE bit is not set. (This was
a major source of Sig-11 type problems.)
vfs_bio.c:
7) Fix a potential system deadlock due to an incorrectly specified
sleep priority while waiting for a buffer write operation. The
change that I made opens the system up to serious problems, and
we need to examine the issue of process sleep priorities.
vfs_cluster.c, vfs_bio.c:
8) Make clustered reads work more correctly (and more completely)
when buffers are already constituted, but not fully valid.
(This was another system reliability issue.)
vfs_subr.c, ffs_inode.c:
9) Create a vtruncbuf function, which is used by filesystems that
can truncate files. The vinvalbuf forced a file sync type operation,
while vtruncbuf only invalidates the buffers past the new end of file,
and also invalidates the appropriate pages. (This was a system reliabiliy
and performance issue.)
10) Modify FFS to use vtruncbuf.
vm_object.c:
11) Make the object rundown mechanism for OBJT_VNODE type objects work
more correctly. Included in that fix, create pager entries for
the OBJT_DEAD pager type, so that paging requests that might slip
in during race conditions are properly handled. (This was a system
reliability issue.)
vm_page.c:
12) Make some of the page validation routines be a little less picky
about arguments passed to them. Also, support page invalidation
change the object generation count so that we handle generation
counts a little more robustly.
vm_pageout.c:
13) Further reduce pageout daemon activity when the system doesn't
need help from it. There should be no additional performance
decrease even when the pageout daemon is running. (This was
a significant performance issue.)
vnode_pager.c:
14) Teach the vnode pager to handle race conditions during vnode
deallocations.
has been some bitrot and incorrect assumptions in the vfs_bio code. These
problems have manifest themselves worse on NFS type filesystems, but can
still affect local filesystems under certain circumstances. Most of
the problems have involved mmap consistancy, and as a side-effect broke
the vfs.ioopt code. This code might have been committed seperately, but
almost everything is interrelated.
1) Allow (pmap_object_init_pt) prefaulting of buffer-busy pages that
are fully valid.
2) Rather than deactivating erroneously read initial (header) pages in
kern_exec, we now free them.
3) Fix the rundown of non-VMIO buffers that are in an inconsistent
(missing vp) state.
4) Fix the disassociation of pages from buffers in brelse. The previous
code had rotted and was faulty in a couple of important circumstances.
5) Remove a gratuitious buffer wakeup in vfs_vmio_release.
6) Remove a crufty and currently unused cluster mechanism for VBLK
files in vfs_bio_awrite. When the code is functional, I'll add back
a cleaner version.
7) The page busy count wakeups assocated with the buffer cache usage were
incorrectly cleaned up in a previous commit by me. Revert to the
original, correct version, but with a cleaner implementation.
8) The cluster read code now tries to keep data associated with buffers
more aggressively (without breaking the heuristics) when it is presumed
that the read data (buffers) will be soon needed.
9) Change to filesystem lockmgr locks so that they use LK_NOPAUSE. The
delay loop waiting is not useful for filesystem locks, due to the
length of the time intervals.
10) Correct and clean-up spec_getpages.
11) Implement a fully functional nfs_getpages, nfs_putpages.
12) Fix nfs_write so that modifications are coherent with the NFS data on
the server disk (at least as well as NFS seems to allow.)
13) Properly support MS_INVALIDATE on NFS.
14) Properly pass down MS_INVALIDATE to lower levels of the VM code from
vm_map_clean.
15) Better support the notion of pages being busy but valid, so that
fewer in-transit waits occur. (use p->busy more for pageouts instead
of PG_BUSY.) Since the page is fully valid, it is still usable for
reads.
16) It is possible (in error) for cached pages to be busy. Make the
page allocation code handle that case correctly. (It should probably
be a printf or panic, but I want the system to handle coding errors
robustly. I'll probably add a printf.)
17) Correct the design and usage of vm_page_sleep. It didn't handle
consistancy problems very well, so make the design a little less
lofty. After vm_page_sleep, if it ever blocked, it is still important
to relookup the page (if the object generation count changed), and
verify it's status (always.)
18) In vm_pageout.c, vm_pageout_clean had rotted, so clean that up.
19) Push the page busy for writes and VM_PROT_READ into vm_pageout_flush.
20) Fix vm_pager_put_pages and it's descendents to support an int flag
instead of a boolean, so that we can pass down the invalidate bit.
a complement to all ops that return a vpp, VFS_VRELE. This is
initially only for file systems that implement the following ops
that do a WILLRELE:
vop_create, vop_whiteout, vop_mknod, vop_remove, vop_link,
vop_rename, vop_mkdir, vop_rmdir, vop_symlink
This is initial DNA that doesn't do anything yet. VFS_VRELE is
implemented but not called.
A default vfs_vrele was created for fs implementations that use the
standard vnode management routines.
VFS_VRELE implementations were made for the following file systems:
Standard (vfs_vrele)
ffs mfs nfs msdosfs devfs ext2fs
Custom
union umapfs
Just EOPNOTSUPP
fdesc procfs kernfs portal cd9660
These implementations may change as VOP changes are implemented.
In the next phase, in the vop implementations calls to vrele and the vrele
part of vput will be moved to the top layer vfs_vnops and made visible
to all layers. vput will be replaced by unlock in these cases. Unlocking
will still be done in the per fs layer but the refcount decrement will be
triggered at the top because it doesn't hurt to hold a vnode reference a
little longer. This will have minimal impact on the structure of the
existing code.
This will only be done for vnode arguments that are released by the various
fs vop implementations.
Wider use of VFS_VRELE will likely require restructuring of the code.
Reviewed by: phk, dyson, terry et. al.
Submitted by: Michael Hancock <michaelh@cet.co.jp>
These diffs implement the first stage of a VOP_{GET|PUT}PAGES pushdown
for local media FS's.
See ffs_putpages in /sys/ufs/ufs/ufs_readwrite.c for implementation
details for generic *_{get|put}pages for local media FS's. Support
is trivial to add for any FS that formerly relied on the default
behaviour of the vnode_pager in in EOPNOTSUPP cases (just copy the
ffs_getpages() code for the FS in question's *_{get|put}pages).
Obviously, it would be better if each local media FS implemented a
more optimal method, instead of calling an exported interface from
the /sys/vm/vnode_pager.c, but this is a necessary first step in
getting the FS's to a point where they can be supplied with better
implementations on a case-by-case basis.
Obviously, the cd9660_putpages() can be rather trivial (since it
is a read-only FS type 8-)).
A slight (temporary) modification is made to print a diagnostic message
in the case where the underlying filesystem attempts to engage in the
previous behaviour. Failure is likely to be ungraceful.
Submitted by: terry@freebsd.org (Terry Lambert)
There is now less need for the vfs.usermount sysctl. msdosfs already
has this change, modulo a missing LK_RETRY, via NetBSD. At least
ext2fs is missing this and many other changes from Lite2.
Obtained from: Lite2
1) Start using TSM.
Struct procs continue to point to upages structure, after being freed.
Struct vmspace continues to point to pte object and kva space for kstack.
u_map is now superfluous.
2) vm_map's don't need to be reference counted. They always exist either
in the kernel or in a vmspace. The vmspaces are managed by reference
counts.
3) Remove the "wired" vm_map nonsense.
4) No need to keep a cache of kernel stack kva's.
5) Get rid of strange looking ++var, and change to var++.
6) Change more data structures to use our "zone" allocator. Added
struct proc, struct vmspace and struct vnode. This saves a significant
amount of kva space and physical memory. Additionally, this enables
TSM for the zone managed memory.
7) Keep ioopt disabled for now.
8) Remove the now bogus "single use" map concept.
9) Use generation counts or id's for data structures residing in TSM, where
it allows us to avoid unneeded restart overhead during traversals, where
blocking might occur.
10) Account better for memory deficits, so the pageout daemon will be able
to make enough memory available (experimental.)
11) Fix some vnode locking problems. (From Tor, I think.)
12) Add a check in ufs_lookup, to avoid lots of unneeded calls to bcmp.
(experimental.)
13) Significantly shrink, cleanup, and make slightly faster the vm_fault.c
code. Use generation counts, get rid of unneded collpase operations,
and clean up the cluster code.
14) Make vm_zone more suitable for TSM.
This commit is partially as a result of discussions and contributions from
other people, including DG, Tor Egge, PHK, and probably others that I
have forgotten to attribute (so let me know, if I forgot.)
This is not the infamous, final cleanup of the vnode stuff, but a necessary
step. Vnode mgmt should be correct, but things might still change, and
there is still some missing stuff (like ioopt, and physical backing of
non-merged cache files, debugging of layering concepts.)
config option in pmap. Fix a problem with faulting in pages. Clean-up
some loose ends in swap pager memory management.
The system should be much more stable, but all subtile bugs aren't fixed yet.
original BSD code. The association between the vnode and the vm_object
no longer includes reference counts. The major difference is that
vm_object's are no longer freed gratuitiously from the vnode, and so
once an object is created for the vnode, it will last as long as the
vnode does.
When a vnode object reference count is incremented, then the underlying
vnode reference count is incremented also. The two "objects" are now
more intimately related, and so the interactions are now much less
complex.
When vnodes are now normally placed onto the free queue with an object still
attached. The rundown of the object happens at vnode rundown time, and
happens with exactly the same filesystem semantics of the original VFS
code. There is absolutely no need for vnode_pager_uncache and other
travesties like that anymore.
A side-effect of these changes is that SMP locking should be much simpler,
the I/O copyin/copyout optimizations work, NFS should be more ponderable,
and further work on layered filesystems should be less frustrating, because
of the totally coherent management of the vnode objects and vnodes.
Please be careful with your system while running this code, but I would
greatly appreciate feedback as soon a reasonably possible.
of vnodes and objects. There are some metadata performance improvements
that come along with this. There are also a few prototypes added when
the need is noticed. Changes include:
1) Cleaning up vref, vget.
2) Removal of the object cache.
3) Nuke vnode_pager_uncache and friends, because they aren't needed anymore.
4) Correct some missing LK_RETRY's in vn_lock.
5) Correct the page range in the code for msync.
Be gentle, and please give me feedback asap.
are used in the `#ifdef notyet' case :-). This case is used except in
the `#if !defined (not_yes)' case :-|. This has something to do with
the `#ifdef notyet_block_reallocation_enabled' case in vfs_cluster.c :-(.
Ever since I first say the way the mount flags were used I've hated the
fact that modes, and events, internal and exported, and short-term
and long term flags are all thrown together. Finally it's annoyed me enough..
This patch to the entire FreeBSD tree adds a second mount flag word
to the mount struct. it is not exported to userspace. I have moved
some of the non exported flags over to this word. this means that we now
have 8 free bits in the mount flags. There are another two that might
well move over, but which I'm not sure about.
The only user visible change would have been in pstat -v, except
that davidg has disabled it anyhow.
I'd still like to move the state flags and the 'command' flags
apart from each other.. e.g. MNT_FORCE really doesn't have the
same semantics as MNT_RDONLY, but that's left for another day.
1. Remove VOP_UPDATE, it is (also) an UFS/{FFS,LFS,EXT2FS,MFS}
intereface function, and now lives in the ufsmount structure.
2. Remove VOP_SEEK, it was unused.
3. Add mode default vops:
VOP_ADVLOCK vop_einval
VOP_CLOSE vop_null
VOP_FSYNC vop_null
VOP_IOCTL vop_enotty
VOP_MMAP vop_einval
VOP_OPEN vop_null
VOP_PATHCONF vop_einval
VOP_READLINK vop_einval
VOP_REALLOCBLKS vop_eopnotsupp
And remove identical functionality from filesystems
4. Add vop_stdpathconf, which returns the canonical stuff. Use
it in the filesystems. (XXX: It's probably wrong that specfs
and fifofs sets this vop, shouldn't it come from the "host"
filesystem, for instance ufs or cd9660 ?)
5. Try to make system wide VOP functions have vop_* names.
6. Initialize the um_* vectors in LFS.
(Recompile your LKMS!!!)
1. Add new file "sys/kern/vfs_default.c" where default actions for
VOPs go. Implement proper defaults for ABORTOP, BWRITE, LEASE,
POLL, REVOKE and STRATEGY. Various stuff spread over the entire
tree belongs here.
2. Change VOP_BLKATOFF to a normal function in cd9660.
3. Kill VOP_BLKATOFF, VOP_TRUNCATE, VOP_VFREE, VOP_VALLOC. These
are private interface functions between UFS and the underlying
storage manager layer (FFS/LFS/MFS/EXT2FS). The functions now
live in struct ufsmount instead.
4. Remove a kludge of VOP_ functions in all filesystems, that did
nothing but obscure the simplicity and break the expandability.
If a filesystem doesn't implement VOP_FOO, it shouldn't have an
entry for it in its vnops table. The system will try to DTRT
if it is not implemented. There are still some cruft left, but
the bulk of it is done.
5. Fix another VCALL in vfs_cache.c (thanks Bruce!)
1. Use the default function to access all the specfs operations.
2. Use the default function to access all the fifofs operations.
3. Use the default function to access all the ufs operations.
4. Fix VCALL usage in vfs_cache.c
5. Use VOCALL to access specfs functions in devfs_vnops.c
6. Staticize most of the spec and fifofs vnops functions.
7. Make UFS panic if it lacks bits of the underlying storage handling.
1. Remove comment stating the blatantly obvious.
2. Align in two columns.
3. Sort all but the default element alphabetically.
4. Remove XXX comments pointing out entries not needed.
Distribute all but the most fundamental malloc types. This time I also
remembered the trick to making things static: Put "static" in front of
them.
A couple of finer points by: bde
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
1. ffs_alloc() actually allowed writing one block less one frag (normally
7 frags or 7/8 blocks) beyond the limit.
2. freebufspace() gives the free space in frags, but `size' is in bytes,
so the change results in approximately `size' fragments too many being
reserved.
3. ffs_realloccg() has the same bug but wasn't changed.
PR: 3398
Submitted by: bde
Eyeballed by: phk
This unifies several times in theory indentical 50 lines of code.
The filesystems have a new method: vop_cachedlookup, which is the
meat of the lookup, and use vfs_cache_lookup() for their vop_lookup
method. vfs_cache_lookup() will check the namecache and pass on
to the vop_cachedlookup method in case of a miss.
It's still the task of the individual filesystems to populate the
namecache with cache_enter().
Filesystems that do not use the namecache will just provide the
vop_lookup method as usual.
socket addresses in mbufs. (Socket buffers are the one exception.) A number
of kernel APIs needed to get fixed in order to make this happen. Also,
fix three protocol families which kept PCBs in mbufs to not malloc them
instead. Delete some old compatibility cruft while we're at it, and add
some new routines in the in_cksum family.
code. According to the crash dump, bpref is set to 445
and cgp->cg_nclusterblks is 444. Hence in the for loop,
the test fails immediately but the following failure check
(got == cgp->cg_nclusterblks) doesn't trigger because got >
cgp->cg_nclusterblks. This wreaks havoc in the code after that.
Fix: Move one source bit to the left :-)
Noticed by: Mike Hibler <mike@fast.cs.utah.edu>
Submitted by: Kirk McKusick <mckusick@McKusick.COM>
automatically have random generation numbers. The kenel way of handling those
also changed. Further it is advised to run fsirand on all your nfs exported
filesystems. the code is mostly copied from OpenBSD, with the randomization
chanegd to use /dev/urandom
Reviewed by: Garrett
Obtained from: OpenBSD
form `tv = time'. Use a new function gettime(). The current version
just forces atomicicity without fixing precision or efficiency bugs.
Simplified some related valid accesses by using the central function.
of setting it (compiled into vfs_conf.c), but we have a dynamic system
in place. This could probably be better done via a runtime configure
flag in the VFS_SET() VFS declaration, perhaps VFCF_LOCAL, and have the
VFS code propagate this down into MNT_LOCAL at mount time. The other FS's
would need to be updated, havinf UFS and MSDOSFS filesystems without
MNT_LOCAL breaks a few things.. the man page rebuild scans for local
filesystems and currently fails, I suspect that other tools like find
and tar with their "local filesystem only" modes might be affected.
Restores the use of SBLOCK instead of the BSOFF/sectorsize calculation.
Using SBLOCK is bogus however in that it uses DEV_BSIZE instead of
the actual sector size, but that is taken care of in other places.
Changing the SBLOCK would be better, but it affects the system
in other places, and doing it this way makes it possible to
use filesystems that was made before the lite2 merge.
to not return without setting a return value when it
can't read a block error or detects a bad cylinder group,
since the caller is expecting a return value.
It will now panic at this point, since the thing
to do in this case would be to return a "bad block"
status to the caller, and the caller will panic
anyways when that happens.
Also updated to panic strings in this routine to read
"ffs_checkblk: ..." instead of "checkblk: ...".
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.
The system boots and can mount UFS filesystems.
Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
Mount_std mounts will not work until the getfsent
library routine is changed.
Reviewed by: various people
Submitted by: Jeffery Hsu <hsu@freebsd.org>
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
We encountered an interesting situation where the superblock for
a file system got written to disk with the "fs_fmod" flag set to
one. It appears that this flag is normally supposed to be cleared
during ffs_sync(), but we experienced a crash, or some other weird
occurrence that left it on the disk set to 1.
Later this partition was mounted read-only... and the fs_fmod
field was never cleared, causing ffs_sync() to panic "rofs mod"
when trying to unmount that filesystem (ffs_vfsops.c: line 790).
fix:
set this bit to 0 when you load the superblock from disk.
(see more complete mail on this to hackers)
ufs_read() and ufs_write().
Found by: looking at warnings for comparing the result of lblktosize()
(which is usually daddr_t = long) with file sizes (which are u_quad_t
for ufs). File sizes should probably be off_t's to avoid warnings
when the are compared with file offsets, so the fixed lblktosize()
casts to off_t instead of u_quad_t.
Added definition of smalllblksize(). It is the same as the old
lblksize() and is more efficient for small block numbers on 32-bit
machines.
Use smalllblktosize() instead of its expansion in blksize() and
dblksize(). This keeps the line length short and makes it more
obvious that the shift can't overflow.
/*
* Structure defined by POSIX.4 to be like a timeval.
*/
struct timespec {
time_t ts_sec; /* seconds */
long ts_nsec; /* and nanoseconds */
};
The correct names of the fields are tv_sec and tv_nsec.
Reminded by: James Drobina <jdrobina@infinet.com>
is that it doesn't say _what_ did it! (the core dumped console message
is very useful for listing the process name and pid). This adds similar
information.
The interface into the "VMIO" system has changed to be more consistant
and robust. Essentially, it is now no longer necessary to call vn_open
to get merged VM/Buffer cache operation, and exceptional conditions
such as merged operation of VBLK devices is simpler and more correct.
This code corrects a potentially large set of problems including the
problems with ktrace output and loaded systems, file create/deletes,
etc.
Most of the changes to NFS are cosmetic and name changes, eliminating
a layer of subroutine calls. The direct calls to vput/vrele have
been re-instituted for better cross platform compatibility.
Reviewed by: davidg
process won't possibly block before filling in the fsnode pointer (v_data)
which might be dereferenced during a sync since the vnode is put on the
mnt_vnodelist by getnewvnode.
Pointed out by Matt Day <mday@artisoft.com>
Speed up for vfs_bio -- addition of a routine bqrelse to greatly diminish
overhead for merged cache.
Efficiency improvement for vfs_cluster. It used to do alot of redundant
calls to cluster_rbuild.
Correct the ordering for vrele of .text and release of credentials.
Use the selective tlb update for 486/586/P6.
Numerous fixes to the size of objects allocated for files. Additionally,
fixes in the various pagers.
Fixes for proper positioning of vnode_pager_setsize in msdosfs and ext2fs.
Fixes in the swap pager for exhausted resources. The pageout code
will not as readily thrash.
Change the page queue flags (PG_ACTIVE, PG_INACTIVE, PG_FREE, PG_CACHE) into
page queue indices (PQ_ACTIVE, PQ_INACTIVE, PQ_FREE, PQ_CACHE),
thereby improving efficiency of several routines.
Eliminate even more unnecessary vm_page_protect operations.
Significantly speed up process forks.
Make vm_object_page_clean more efficient, thereby eliminating the pause
that happens every 30seconds.
Make sequential clustered writes B_ASYNC instead of B_DELWRI even in the
case of filesystems mounted async.
Fix a panic with busy pages when write clustering is done for non-VMIO
buffers.
This fixes PR943.
ffs/ffs_vfsops.c:
ffs_statfs() multiplied by (100 - minfree) as part of calculating the
minfree percentage (complemented in 100%), so with the standard minfree
of 8, it was broken for file systems of size >= 1TB/92 = 11GB. Use the
standard freespace() macro instead. This also fixes a rounding bug (the
"Avail" count was sometimes 1 too small).
ffs/* (not fixed):
The freespace() macro multiplies by minfree, so with the standard
minfree of 8, it is broken for file systems of size >= 1TB/8 = 128GB.
This bug is more serious since it affects block allocation.
ffs/ffs_alloc.c (not fixed):
Ordinary users are sometimes allowed to allocate 1 (partial) block
too many so that the "Avail" count goes negative. E.g., if there is
1 fragment available and the file is fairly large, one more full
block is allocated.
df/df.c:
ufs_df() used/uses essentially the same code as ffs_statfs(), so it
had/has the same bugs.
ufs_df() gratuitously replaced "Avail" counts of < 0 by 0, so it
gave different results for non-mounted file systems in this case.
1) Make cluster buffer list be a non-malloced chain. This eliminates
yet another 'evil' M_WAITOK and generally cleans up the code.
2) Fix write clustering for ext2fs. It was just broken. Also, ffs
clustering had an efficiency problem that more bawrites were happening
than should have been.
3) Make changes to buf.h to support the above, plus remove b_pfcent
at the request of David Greenman.
Note that the reallocblocks code is disabled pending rewrite for
the cluster buffer list changes.
