Made a new (inline) function devsw(dev_t dev) and substituted it.
Changed to the BDEV variant to this format as well: bdevsw(dev_t dev)
DEVFS will eventually benefit from this change too.
Virtualize bdevsw[] from cdevsw. bdevsw() is now an (inline)
function.
Join CDEV_MODULE and BDEV_MODULE to DEV_MODULE (please pay attention
to the order of the cmaj/bmaj arguments!)
Join CDEV_DRIVER_MODULE and BDEV_DRIVER_MODULE to DEV_DRIVER_MODULE
(ditto!)
(Next step will be to convert all bdev dev_t's to cdev dev_t's
before they get to do any damage^H^H^H^H^H^Hwork in the kernel.)
files at once on a filesystem running soft updates. The root of
the problem is that soft updates limits the amount of memory that
may be allocated to dependency structures so as to avoid hogging
kernel memory. The original algorithm just waited for the disk I/O
to catch up and reduce the number of dependencies. This new code
takes a much more aggressive approach. Basically there are two
resources that routinely hit the limit. Inode dependencies during
periods with a high file creation rate and file and block removal
dependencies during periods with a high file removal rate. I have
attacked these problems from two fronts. When the inode dependency
limits are reached, I pick a random inode dependency, UFS_UPDATE
it together with all the other dirty inodes contained within its
disk block and then write that disk block. This trick usually
clears 5-50 inode dependencies in a single disk I/O. For block and
file removal dependencies, I pick a random directory page that has
at least one remove pending and VOP_FSYNC its directory. That
releases all its removal dependencies to the work queue. To further
hasten things along, I also immediately start the work queue process
rather than waiting for its next one second scheduled run.
piecemeal, middle-of-file writes for NFS. These hacks have caused no
end of trouble, especially when combined with mmap(). I've removed
them. Instead, NFS will issue a read-before-write to fully
instantiate the struct buf containing the write. NFS does, however,
optimize piecemeal appends to files. For most common file operations,
you will not notice the difference. The sole remaining fragment in
the VFS/BIO system is b_dirtyoff/end, which NFS uses to avoid cache
coherency issues with read-merge-write style operations. NFS also
optimizes the write-covers-entire-buffer case by avoiding the
read-before-write. There is quite a bit of room for further
optimization in these areas.
The VM system marks pages fully-valid (AKA vm_page_t->valid =
VM_PAGE_BITS_ALL) in several places, most noteably in vm_fault. This
is not correct operation. The vm_pager_get_pages() code is now
responsible for marking VM pages all-valid. A number of VM helper
routines have been added to aid in zeroing-out the invalid portions of
a VM page prior to the page being marked all-valid. This operation is
necessary to properly support mmap(). The zeroing occurs most often
when dealing with file-EOF situations. Several bugs have been fixed
in the NFS subsystem, including bits handling file and directory EOF
situations and buf->b_flags consistancy issues relating to clearing
B_ERROR & B_INVAL, and handling B_DONE.
getblk() and allocbuf() have been rewritten. B_CACHE operation is now
formally defined in comments and more straightforward in
implementation. B_CACHE for VMIO buffers is based on the validity of
the backing store. B_CACHE for non-VMIO buffers is based simply on
whether the buffer is B_INVAL or not (B_CACHE set if B_INVAL clear,
and vise-versa). biodone() is now responsible for setting B_CACHE
when a successful read completes. B_CACHE is also set when a bdwrite()
is initiated and when a bwrite() is initiated. VFS VOP_BWRITE
routines (there are only two - nfs_bwrite() and bwrite()) are now
expected to set B_CACHE. This means that bowrite() and bawrite() also
set B_CACHE indirectly.
There are a number of places in the code which were previously using
buf->b_bufsize (which is DEV_BSIZE aligned) when they should have
been using buf->b_bcount. These have been fixed. getblk() now clears
B_DONE on return because the rest of the system is so bad about
dealing with B_DONE.
Major fixes to NFS/TCP have been made. A server-side bug could cause
requests to be lost by the server due to nfs_realign() overwriting
other rpc's in the same TCP mbuf chain. The server's kernel must be
recompiled to get the benefit of the fixes.
Submitted by: Matthew Dillon <dillon@apollo.backplane.com>
This is a seriously beefed up chroot kind of thing. The process
is jailed along the same lines as a chroot does it, but with
additional tough restrictions imposed on what the superuser can do.
For all I know, it is safe to hand over the root bit inside a
prison to the customer living in that prison, this is what
it was developed for in fact: "real virtual servers".
Each prison has an ip number associated with it, which all IP
communications will be coerced to use and each prison has its own
hostname.
Needless to say, you need more RAM this way, but the advantage is
that each customer can run their own particular version of apache
and not stomp on the toes of their neighbors.
It generally does what one would expect, but setting up a jail
still takes a little knowledge.
A few notes:
I have no scripts for setting up a jail, don't ask me for them.
The IP number should be an alias on one of the interfaces.
mount a /proc in each jail, it will make ps more useable.
/proc/<pid>/status tells the hostname of the prison for
jailed processes.
Quotas are only sensible if you have a mountpoint per prison.
There are no privisions for stopping resource-hogging.
Some "#ifdef INET" and similar may be missing (send patches!)
If somebody wants to take it from here and develop it into
more of a "virtual machine" they should be most welcome!
Tools, comments, patches & documentation most welcome.
Have fun...
Sponsored by: http://www.rndassociates.com/
Run for almost a year by: http://www.servetheweb.com/
1:
s/suser/suser_xxx/
2:
Add new function: suser(struct proc *), prototyped in <sys/proc.h>.
3:
s/suser_xxx(\([a-zA-Z0-9_]*\)->p_ucred, \&\1->p_acflag)/suser(\1)/
The remaining suser_xxx() calls will be scrutinized and dealt with
later.
There may be some unneeded #include <sys/cred.h>, but they are left
as an exercise for Bruce.
More changes to the suser() API will come along with the "jail" code.
unallocated parts of the last page when the file ended on a frag
but not a page boundary.
Delimitted by tags PRE_MATT_MMAP_EOF and POST_MATT_MMAP_EOF,
in files alpha/alpha/pmap.c i386/i386/pmap.c nfs/nfs_bio.c vm/pmap.h
vm/vm_page.c vm/vm_page.h vm/vnode_pager.c miscfs/specfs/spec_vnops.c
ufs/ufs/ufs_readwrite.c kern/vfs_bio.c
Submitted by: Matt Dillon <dillon@freebsd.org>
Reviewed by: Alan Cox <alc@freebsd.org>
in my tree for 12+ months, and I just noticed that NetBSD have (I think,
I've just seen the commit, not the change) just zapped it there.
It wasn't in the options files or LINT either.
include of <sys/queue.h> in the !KERNEL case. The prerequisites
for <ufs/ufs/quota.h> were broken in Lite2 by converting some of
the kernel declarations to use queue macros without including
<sys/queue.h>. <sys/queue.h> was included in applications in
/usr/src instead. We polluted this file instead of merging the
changes in the applications.
Include <sys/queue.h> in the KERNEL case, and forward-declare all
structs that are used in prototypes, so that this file is almost
self-sufficient even in the kernel.
Obtained from: mostly from NetBSD
so that non-sloppy applications can call it without using disgusting
casts to avoid warnings. The 4th arg is sort of varargs -- it must
sometimes represent a filename, sometimes a struct pointer, and is
sometimes unused. The arg type is still caddr_t in the kernel.
Obtained from: mostly from NetBSD
lives in ext2_vnops.c for ext2fs. Also remove cast from comparision.
Bruce pointed out that it was bogus since we'd force a signed
comparision when we really wanted an unsigned comparison.
to write all the dirty blocks. If some of those blocks have dependencies,
they will be remarked dirty when the I/O completes. On systems with
really fast I/O systems, it is possible to get in an infinite loop trying
to flush the buffers, because the I/O finishes before we can get all the
dirty buffers off the v_dirtyblkhd list and into the I/O queue. (The
previous algorithm looped over the v_dirtyblkhd list writing out buffers
until the list emptied.) So, now we mark each buffer that we try to
write so that we can distinguish the ones that are being remarked dirty
from those that we have not yet tried to flush. Once we have tried to
push every buffer once, we then push any associated metadata that is
causing the remaining buffers to be redirtied.
Submitted by: Matthew Dillon <dillon@apollo.backplane.com>
Specifically, the test was in the wrong place, lacked a cast, didn't
unlock the node, and exited to bad rather than abortit. Now we don't
allow renaming of a file with LINK_MAX references. Move the test to
earlier in the code as it is closer to where ip is obtained, as that
is the style of the rest of the function.
Didn't fix the problems bruce pointed out in the rename man page to
include EMLINK, nor address his complaints about how the whole idea of
incrementing the link count during a rename is potentially asking for
trouble.
Also didn't try to correct potential problem Terry pointed out with
decrements not being similarly protected against underflow.
turns out to not be useful to unwind the dependencies and continue in
the face of a fatal error.
Also changed the log() to a printf() in softdep_error() so that it will
be output in the case of a impending panic.
Submitted by: Kirk McKusick <mckusick@mckusick.com>
changes to the VM system to support the new swapper, VM bug
fixes, several VM optimizations, and some additional revamping of the
VM code. The specific bug fixes will be documented with additional
forced commits. This commit is somewhat rough in regards to code
cleanup issues.
Reviewed by: "John S. Dyson" <root@dyson.iquest.net>, "David Greenman" <dg@root.com>
MNT_WAIT when we mean boolean `true' or check for that value not being
passed. There was no problem in practice because MNT_WAIT had the
magic value of 1.
I/O requests must be marked P_SYSTEM because if it isn't and the system
decides to swap it or (god forbid) kill it, the system stands a good
chance of locking up.
may be revoked, so vnop routines must be careful about accessing
the vnode if they may have blocked.
Fixed marking for update after successfully reading or writing 0
bytes. In this case, POSIX.1 specifies marking if and only if the
requested count is nonzero, but rev.1.86 never marked.
basically do a on-the-fly defragmentation of the FFS filesystem, changing
file block allocations to make them contiguous. Thanks to Kirk McKusick
for providing hints on what needed to be done to get this working.
They checked for the magic major number for the "device" behind mfs
mount points. Use a more obvious check for this device.
Debugged by: Andrew Gallatin <gallatin@cs.duke.edu>
when bdevsw[] became sparse. We still depend on magic to avoid having to
check that (v_rdev) device numbers in vnodes are not NODEV.
Removed redundant `major(dev) < nblkdev' tests instead of updating them.
partition that the label ioctl is being done on just because it has
offset 0, since there is no guarantee that such a partition is large
enough to contain the label. Don't use the wrong raw partition (0
instead of RAW_PART).
This fixes problems rewriting bizarre labels (with a nonzero offset
for the 'a' partition) in newfs(8). Such labels shouldn't normally
be used, but creating them was allowed if the ioctl was done on the
raw partition, and sysinstall creates them if the root partition isn't
allocated first.
Note that allowing write access to a partition other than the one that
has been checked for write access doesn't increase security holes
significantly, since write access to any partition already allows
changing the in-core label.
This fix should be in 3.0R. Rev.1.26 of newfs/newfs.c shouldn't be
in 3.0R.
but when i_effnlink was added to support soft updates, there was only
room for 4 spares. The number of spares was not reduced, so the inode
size became 260 (on i386's), or 512 after rounding up by malloc().
Use one spare field in `struct dinode' instead of the 5th spare field
in the inode and reduced to 4 spares in the inode so that the size is
256 again.
Changed the types of the spares in the inode from int to u_int32_t
so that the inode size has more chance of being <= 256 under other
arches, and downdated ext2fs to match (it was broken to use ints
before rev.1.1).
As a side effect, a few wakeup() calls are added, which might fix some of the
missing vm_page wakeups people have been seeing.
Reviewed by: Doug Rabson <dfr@nlsystems.com>
The problem is caused when a directory block is compacted. When this
occurs, softdep_change_directoryentry_offset() is called to relocate each
directory entry and adjust its matching diradd structure, if any, to match
the new location of the entry. The bug is that while
softdep_change_directoryentry_offset() correctly adjusts the offsets of
the diradd structures on the pd_diraddhd[] lists (which are not yet ready
to be committed to disk), it fails to adjust the offsets of the diradd
structures on the pd_pendinghd list (which are ready to be committed to
disk). This causes the dependency structures to be inconsistent with
the buf contents. Now, if the compaction has moved a directory entry to
the same offset as one of the diradd structures on the pd_pendinghd list
*and* a syscall is done that tries to remove this directory entry before
this directory block has been written to disk (which would empty
pd_pendinghd), a sanity check in newdirrem() will call panic() when it
notices that the inode number in the entry that it is to be removed doesn't
match the inode number in the diradd structure with that offset of that
entry.
Reviewed by: Kirk McKusick <mckusick@McKusick.COM>
Submitted by: Don Lewis <Don.Lewis@tsc.tdk.com>
happen when an NFS exported filesystem tries to remove a locally
mounted on directory.
PR: kern/7272
Submitted by: Andre Albsmeier <andre.albsmeier@mchp.siemens.de>
- don't set the clean flag on unmount of an unclean filesystem that was
(forcibly) mounted rw.
- set the clean flag on rw -> ro update of a mounted initially-clean
filesystem.
- fixed some style bugs (mostly long lines).
This uses the fs_flags field and FS_UNCLEAN state bit which were
introduced in the softdep changes. NetBSD uses extra state bits in
fs_clean.
Reviewed by: luoqui
Submitted by: Kirk McKusick <mckusick@McKusick.COM>
Two minor changes are also included,
1. Remove gratuitious checks for error return from vn_lock with LK_RETRY set,
vn_lock should always succeed in these cases.
2. Back out change rev. 1.36->1.37, which unnecessarily makes async mount
a little more unstable. It also keeps us in sync with other BSDs.
Suggested by: Bruce Evans <bde@zeta.org.au>
references to them.
The change a couple of days ago to ignore these numbers in statically
configured vfsconf structs was slightly premature because the cd9660,
cfs, devfs, ext2fs, nfs vfs's still used MOUNT_* instead of the number
in their vfsconf struct.
device drivers about sectors no longer in use.
Device-drivers receive the call through d_strategy, if they have
D_CANFREE in d_flags.
This allows flash based devices to erase the sectors and avoid
pointlessly carrying them around in compactions.
Reviewed by: Kirk Mckusick, bde
Sponsored by: M-Systems (www.m-sys.com)
clustering is obsolescent technology so hardly anyone noticed. On
a DORS 32160 SCSI drive with 4 tags, read clustering makes very
little difference even for huge sequential reads. However, on a
ZIP SCSI drive with 0 tags, the minimum overhead per block is about
40 msec, so very large clusters must be used to get anywhere near
the maximum transfer rate. Using clusters consisting of 1 8K block
reduces the transfer rate to about 250K/sec. Under msdosfs, missing
read clustering is normal and a cluster size of 1 512 byte block
reduces the transfer rate to about 25K/sec.
Broken in: rev.1.18
formats and args to match. Fixed old printf format errors (all related;
most were hidden by calling printf indirectly).
This change somehow avoids compiler bugs for 64-bit longs on i386's,
although it increases the number of 64-bit calculations.
respectively. Most of the longs should probably have been
u_longs, but this changes is just to prevent warnings about
casts between pointers and integers of different sizes, not
to fix poorly chosen types.
as the value in b_vp is often not really what you want.
(and needs to be frobbed). more cleanups will follow this.
Reviewed by: Bruce Evans <bde@freebsd.org>
as possible (when the inode is reclaimed). Temporarily only do
this if option UFS_LAZYMOD configured and softupdates aren't enabled.
UFS_LAZYMOD is intentionally left out of /sys/conf/options.
This is mainly to avoid almost useless disk i/o on battery powered
machines. It's silly to write to disk (on the next sync or when the
inode becomes inactive) just because someone hit a key or something
wrote to the screen or /dev/null.
PR: 5577
Previous version reviewed by: phk
in ufs_setattr() so that there is no need to pass timestamps to
UFS_UPDATE() (everything else just needs the current time). Ignore
the passed-in timestamps in UFS_UPDATE() and always call ufs_itimes()
(was: itimes()) to do the update. The timestamps are still passed
so that all the callers don't need to be changed yet.
that had an inode that has not yet been written to disk, when the inode of the
new file is also not yet written to disk, and your old directory entry is not
yet on disk but you need to remove it and the new name exists in memory
but has been deleted but the transaction to write the deleted name to disk
exists and has not yet been cancelled by the request to delete the non
existant name. I don't know how kirk could have missed such a glaring
problem for so long. :-) Especially since the inconsitency survived on
the disk for a whole 4 second on average before being fixed by other code.
This was not a crashing bug but just led to filesystem inconsitencies
if you crashed.
Submitted by: Kirk McKusick (mckusick@mckusick.com)
(doingdirectory && !newparent) case of ufs_rename().
rename("D1/X/", "D2/Y/") gives a wrong link count for D2.
Submitted by: Bruce Evans <bde@zeta.org.au>
Reviewed by: Kirk McKusick <mckusick@McKusick.COM>
is now ignored for special files, so that mounting root with option
noatime doesn't break reporting of idle times in programs like `w'.
The problem of execessive disk updates just to stamp atimes will be
handled for special files by only writing atimes to disk when inodes
become active. This works well because special files are relatively
uncommon and their atimes are even more disposable at panic time than
regular files' atimes.
1. mark atimes and mtimes of special files and fifos for update upon
successful completion of non-null i/o, not at the beginning of the
syscall.
2. never update file times for readonly filesystems. They were updated
for stats and closes but not for syncs. The updates were of course
only in-core and were thrown away when the inode was uncached, so
the times sometimes appeared to go backwards.
Improved comments in code related to (1) (mostly by removing them).
Unmacroized ITIMES(). The test in (2) bloated it even more. Don't
call getmicrotime() in the function version of it when we only need
the time in seconds.
---------
Make callers of namei() responsible for releasing references or locks
instead of having the underlying filesystems do it. This eliminates
redundancy in all terminal filesystems and makes it possible for stacked
transport layers such as umapfs or nullfs to operate correctly.
Quality testing was done with testvn, and lat_fs from the lmbench suite.
Some NFS client testing courtesy of Patrik Kudo.
vop_mknod and vop_symlink still release the returned vpp. vop_rename
still releases 4 vnode arguments before it returns. These remaining cases
will be corrected in the next set of patches.
---------
Submitted by: Michael Hancock <michaelh@cet.co.jp>
Reverse the VFS_VRELE patch. Reference counting of vnodes does not need
to be done per-fs. I noticed this while fixing vfs layering violations.
Doing reference counting in generic code is also the preference cited by
John Heidemann in recent discussions with him.
The implementation of alternative vnode management per-fs is still a valid
requirement for some filesystems but will be revisited sometime later,
most likely using a different framework.
Submitted by: Michael Hancock <michaelh@cet.co.jp>
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.
- restored async mount support. The first entry in a block is still
always written synchronously, although it probably shouldn't be in
the async case.
- restored use of BWRITE() instead of bowrite() for the DOWHITEOUT
case, although bowrite() is probably better.
Broken by: merge of softdep changes (rev.1.22).
Found by: lmbench2 delete-file benchmarks.
(because we can :-). This means you can open a link file (or pseudo-file
in the case of short links where the data is stored in the inode rather
than disk blocks) and read the contents.
However, trap any writes from the user as it's difficult to do the right
thing in all cases. A link may be short and the user may be trying to
extend it beyond the limit and so on. Although.. being able to re-target
a symlink without deleting it first might have been nice.
This stuff is a bit perverse since symlink() and readlink() calls can
end up actually being implemented as read/write vnode ops.
Reviewed by: phk
* Figure out UTC relative to boottime. Four new functions provide
time relative to boottime.
* move "runtime" into struct proc. This helps fix the calcru()
problem in SMP.
* kill mono_time.
* add timespec{add|sub|cmp} macros to time.h. (XXX: These may change!)
* nanosleep, select & poll takes long sleeps one day at a time
Reviewed by: bde
Tested by: ache and others
"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
of the various ad-hoc schemes.
2) When bringing in UPAGES, the pmap code needs to do another vm_page_lookup.
3) When appropriate, set the PG_A or PG_M bits a-priori to both avoid some
processor errata, and to minimize redundant processor updating of page
tables.
4) Modify pmap_protect so that it can only remove permissions (as it
originally supported.) The additional capability is not needed.
5) Streamline read-only to read-write page mappings.
6) For pmap_copy_page, don't enable write mapping for source page.
7) Correct and clean-up pmap_incore.
8) Cluster initial kern_exec pagin.
9) Removal of some minor lint from kern_malloc.
10) Correct some ioopt code.
11) Remove some dead code from the MI swapout routine.
12) Correct vm_object_deallocate (to remove backing_object ref.)
13) Fix dead object handling, that had problems under heavy memory load.
14) Add minor vm_page_lookup improvements.
15) Some pages are not in objects, and make sure that the vm_page.c can
properly support such pages.
16) Add some more page deficit handling.
17) Some minor code readability improvements.
If you want to play with it, you can find the final version of the
code in the repository the tag LFS_RETIREMENT.
If somebody makes LFS work again, adding it back is certainly
desireable, but as it is now nobody seems to care much about it,
and it has suffered considerable bitrot since its somewhat haphazard
integration.
R.I.P
This introduce an xxxFS_BOOT for each of the rootable filesystems.
(Presently not required, but encouraged to allow a smooth move of option *FS
to opt_dontuse.h later.)
LFS is temporarily disabled, and will be re-enabled tomorrow.
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.
if one of the new poll types is requested; hopefully this will not break
any existing code. (This is done so that programs have a dependable
way of determining whether a filesystem supports the extended poll types
or not.)
The new poll types added are:
POLLWRITE - file contents may have been modified
POLLNLINK - file was linked, unlinked, or renamed
POLLATTRIB - file's attributes may have been changed
POLLEXTEND - file was extended
Note that the internal operation of poll() means that it is impossible
for two processes to reliably poll for the same event (this could
be fixed but may not be worth it), so it is not possible to rewrite
`tail -f' to use poll at this time.
general to be of much use. Using it here broke the _PC_NAME_MAX,
_PC_NO_TRUNC and _PC_PATH_MAX cases, and weakened the _PC_MAX_CANON,
_PC_MAX_INPUT and _PC_VDISABLE cases.
triple indirect blocks only worked for block sizes of 4K, since
MNINDIR(ump)**3 overflows for larger block sizes (e.g.,
(8192/4)**3 = 2**33 > INT_MAX). This fix is not the obvious one of
changing some types to 64 bits. It rearranges the code to avoid some
unnecessary 64-bit calculations.
Reviewed by: Kirk McKusick <mckusick@McKusick.COM>
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 :-(.
it if the file system is mounted noatime). Not fixed: the access
time is marked at the start of a read() and not marked on successful
completion. I think this should be handled at the vfs level.
Print a better panic message for missing vops. Don't use printf()
before panic(), since the printf()ed part isn't shown by gdb.
This actually loses a little with the current gdb, since gdb just
prints the fmt arg to panic, so %'s aren't expanded. gdb should
fetch the full message from the message buffer if possible.
Fixed default vop function for vop_getpages_desc. It needs to
just return EOPNOTSUPP so that the vnode pager can get the pages
in using a general method. Panicing broke exec'ing of files on
ext2fs file systems. ffs works because it doesn't use the default.
Fixed nearby style bugs.
Obtained from: Whistle Communications tree
Add an option to the way UFS works dependent on the SUID bit of directories
This changes makes things a whole lot simpler on systems running as
fileservers for PCs and MACS. to enable the new code you must
1/ enable option SUIDDIR on the kernel.
2/ mount the filesystem with option suiddir.
hopefully this makes it difficult enough for people to
do this accidentally.
see the new chmod(2) man page for detailed info.
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.
it in struct proc instead.
This fixes a boatload of compiler warning, and removes a lot of cruft
from the sources.
I have not removed the /*ARGSUSED*/, they will require some looking at.
libkvm, ps and other userland struct proc frobbing programs will need
recompiled.
Rename vn_default_error to vop_defaultop all over the place.
Move vn_bwrite from vfs_bio.c to vfs_default.c and call it vop_stdbwrite.
Use vop_null instead of nullop.
Move vop_nopoll from vfs_subr.c to vfs_default.c
Move vop_sharedlock from vfs_subr.c to vfs_default.c
Move vop_nolock from vfs_subr.c to vfs_default.c
Move vop_nounlock from vfs_subr.c to vfs_default.c
Move vop_noislocked from vfs_subr.c to vfs_default.c
Use vop_ebadf instead of *_ebadf.
Add vop_defaultop for getpages on master vnode in MFS.
1. Add defaults for more VOPs
VOP_LOCK vop_nolock
VOP_ISLOCKED vop_noislocked
VOP_UNLOCK vop_nounlock
and remove direct reference in filesystems.
2. Rename the nfsv2 vnop tables to improve sorting order.
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.
ip->i_flags.
Rev.1.18 completely broke ufs. My root directory went away about 10
seconds after booting. I think file system damage was null, since
IN_HASHED = 0x80 is not used in the disk flags (it would probably
be UF_SOMETHING if it were used).
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
plus the previous changes to use the zone allocator decrease the useage
of malloc by half. The Zone allocator will be upgradeable to be able
to use per CPU-pools, and has more intelligent usage of SPLs. Additionally,
it has reasonable stats gathering capabilities, while making most calls
inline.
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
Introduce VFREE which indicates that vnode is on freelist.
Rename vholdrele() to vdrop().
Create vfree() and vbusy() to add/delete vnode from freelist.
Add vfree()/vbusy() to keep (v_holdcnt != 0 || v_usecount != 0)
vnodes off the freelist.
Generalize vhold()/v_holdcnt to mean "do not recycle".
Fix reassignbuf()s lack of use of vhold().
Use vhold() instead of checking v_cache_src list.
Remove vtouch(), the vnodes are always vget'ed soon enough
after for it to have any measuable effect.
Add sysctl debug.freevnodes to keep track of things.
Move cache_purge() up in getnewvnodes to avoid race.
Decrement v_usecount after VOP_INACTIVE(), put a vhold() on
it during VOP_INACTIVE()
Unmacroize vhold()/vdrop()
Print out VDOOMED and VFREE flags (XXX: should use %b)
Reviewed by: dyson
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.
free list problem. Also, the vnode age flag is no longer used by the
vnode pager. (It is actually incorrect to use then.) Constructive
feedback welcome -- just be kind.
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>
chown(). Previously, it wasn't marked for null chown()'s. We
permit null chown()s as a special case of "appropriate privilege"
- everyone has enough priviilege to not change ids (this is a better
argument than the one I gave for rev.1.13, that null changes aren't
really changes). However, POSIX.1 requires the update independently
of whether anything has changed.
Clear both the setuid and the setgid bits upon successful completion
of non-null chown()s by non-root. Previously, the setuid bit was
only changed for non-null changes of the uid, etc. POSIX.1 requires
clearing both unless the call was made by a process with "appropriate
privilege", in which case altering the bits is implementation-defined.
We define appropriate privilege as `process is root, or the change
is null', and the implementation-defined behaviour as not altering
the bits. There is no interpretation that permits clearing only
one of the bits.
Reviewed by: jdp
cause a problem of spiraling death due to buffer resource limitations.
The vfs_bio code in general had little ability to handle buffer resource
management, and now it does. Also, there are a lot more knobs for tuning the
vfs_bio code now. The knobs came free because of the need that there
always be some immediately available buffers (non-delayed or locked) for
use. Note that the buffer cache code is much less likely to get bogged
down with lots of delayed writes, even more so than before.
These changes add the ability to specify that a UFS file/directory
cannot be unlinked. This is basically a scaled back version
of the IMMUTABLE flag. The reason is to allow an administrator
to create a directory hierarchy that a group of users
can arbitrarily add/delete files from, but that the hierarchy
itself is safe from removal by them.
If the NOUNLINK definition is set to 0
then this results in no change to what happens normally.
(and results in identical binary (in the kernel)).
It can be proven that if this bit is never set by the admin,
no new behaviour is introduced..
Several "good idea" comments from reviewers plus one grumble
about creeping featurism.
This code is in production in 2.2 based systems
defining doff_t both here and in <ufs/ufs/dir.h> so that this file
is independent of <ufs/ufs/dir.h>. It still has old prerequisites
<sys/param.h> and <ufs/ufs/quota.h>, and a new Lite2 prerequisite of
<sys/lock.h>, sigh.
This might fix lsof, which was broken by namespace pollution giving
conflicting definitions of DIRBLKSIZ.
as shadows of their containing directory. This should solve the problem
of users not being able to delete their symlinks from /tmp once and for
all.
Symlinks do not have modes though, they are accessable to everything that
can read the directory (as before). They are made to show this fact at
lstat time (they appear as mode 0777 always, since that's how the the
lookup routines in the kernel treat them).
More commits will follow, eg: add a real lchown() syscall and man pages.
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
null casts. `time' is nonvolatile for accesses within a region locked
by splclock()/splx(). Accesses outside such a region are invalid, and
splx() must have the side effect of potentially changing all global
variables (since there are hundreds of sort of volatile variables like
`time'), so declaring `time' as volatile didn't have any real benefits.
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.
mount. This may have been a contributor to the 'null v_mount in
fsync()' problem
This is another, perhaps slightly less urgent, 2.2 last-minute candidate.
Reviewed by: sef
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.
Firstly, now our read-ahead clustering is on a file descriptor basis and not
on a per-vnode basis. This will allow multiple processes reading the
same file to take advantage of read-ahead clustering. Secondly, there
previously was a problem with large reads still using the ramp-up
algorithm. Of course, that was bogus, and now we read the entire
"chunk" off of the disk in one operation. The read-ahead clustering
algorithm should use less CPU than the previous also (I hope :-)).
NOTE: THAT LKMS MUST BE REBUILT!!!
makes MADV_SEQUENTIAL much more effective. I suggest that
we start using MADV_SEQUENTIAL on system utilities that mmap
their input files, and the I/O is predominantely sequential.
Below is a test with 'cmp' on two relatively large binary files,
where the files are so large that the caching is ineffective:
+ ls -l t1.xxx t2.xxx
-rw-r--r-- 1 root wheel 65598384 Dec 10 12:13 t1.xxx
-rw-r--r-- 1 root wheel 65598384 Dec 10 12:14 t2.xxx
+ time cmp t1.xxx t2.xxx
3.78user 0.70system 1:33.43elapsed 4%CPU
+ time cmpmadv t1.xxx t2.xxx
4.21user 1.05system 0:30.93elapsed 17%CPU
This change is as a result of an observation made by BDE.
the sd & od drivers. There is also slight changes to fdisk & newfs
in order to comply with different sectorsizes.
Currently sectors of size 512, 1024 & 2048 are supported, the only
restriction beeing in fdisk, which hunts for the sectorsize of
the device.
This is based on patches to od.c and the other system files by
John Gumb & Barry Scott, minor changes and the sd.c patches by
me.
There also exist some patches for the msdos filesys code, but I
havn't been able to test those (yet).
John Gumb (john@talisker.demon.co.uk)
Barry Scott (barry@scottb.demon.co.uk)
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)
1. When a directory is renamed to an existing (empty) directory,
it is possible for the target vnode to become the source vnode
underneath you (because another process may complete the same
rename). It was assumed that this can't happen, and the bogus
errno EINVAL was returned. This was fairly harmless.
Fix: return ENOENT instead, as if the source directory was renamed
a little earlier.
2. The same metamorphosis is possible for non-directories. It was
assumed that this can't happen, and the code for handling "just
removing a link name" happened to be used. This would have worked
except for fatal bugs in the link name removal - the link name was
assumed to still be there, and a null pointer was followed.
Fix: check the result of relookup(). This fixes PR 1930.
Notes:
(a) POSIX seems to say that removing link names shall have no effect.
BSD (4.4Lite2 at least) does something reasonable instead.
(b) The relookup() may find a file unrelated to the original.
Removing this isn't correct. Consider 3 existing files A, B and
C, and concurrent renames: AB = rename(A, B), another AB, and
CA = rename("c", "a"). If rename() is atomic, then only the
following results are possible:
AB, AB (fails), CA: A = original C, B = original A, C = gone
AB, CA, AB: A = gone, B = original C, C = gone
CA, AB, AB (fails): A = gone, B = original C, C = gone
but ufs_rename() can give:
A,AB,CA,B (sorta): A = gone, B = original A, C = gone
This usually doesn't matter, since getting into a race is usually
an error.
---
These fixes should be in 2.1.6 and 2.2.
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.
It is needed for implementation details but very little of it is
needed for the interface. Include it in the few places that didn't
already include it.
Include <sys/ioccom.h> in <sys/disklabel.h> (as already in
<sys/diskslice.h>) so that all the disk-related headers are almost
self-sufficient.
/*
* 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 file access time update on reads and can be useful in reducing
filesystem overhead in cases where the access time is not important (like
Usenet news spools).
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>
and B_READ before writing. This was was fatal. They also broke the
clearing of B_INVAL before doing i/o. This didn't actually matter.
Submitted by: mostly by joerg
be called with the directory referenced, and this reference will
be dropped iff relookup() fails, so the value returned must not be
ignored.
Reviewed by: davidg
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.
is possible to boot a kernel with an empty in-core MFS image, and have
it load the image from floppy directly. This is admittedly a hack and
would be better replaced by a self-loading ram-disk.
What was happening, was that the main mfs loop was sleeping, and when it was
being awoken by a wakeup when it was supposed to process some IO requests.
The problem was that if it was being woken out of the tsleep() by a signal
at shutdown, it was going straight into dounmount() without servicing any
pending IO requests, causing dounmount() to fail because there were busy
buffers (and they could not be "processed" because the processing loop was
trying to unmount rather than dispatching into mfs_doio()).
This (dare I say it :-) appears to be a layering problem....
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.
structs and prototypes for syscalls.
Ifdefed duplicated decentralized declarations of args structs. It's
convenient to have this visible but they are hard to maintain. Some
are already different from the central declarations. 4.4lite2 puts
them in comments in the function headers but I wanted to avoid the
large changes for that.
it 1138 times (:-() in casts and a few more times in declarations.
This change is null for the i386.
The type has to be `typedef int vop_t(void *)' and not `typedef
int vop_t()' because `gcc -Wstrict-prototypes' warns about the
latter. Since vnode op functions are called with args of different
(struct pointer) types, neither of these function types is any use
for type checking of the arg, so it would be preferable not to use
the complete function type, especially since using the complete
type requires adding 1138 casts to avoid compiler warnings and
another 40+ casts to reverse the function pointer conversions before
calling the functions.
earlier discussions with DG, and a recent email exchange with SEF, I
decided to allow UFS to run wide-open on an experimental basis. We
will probably support eventually multiple async modes, and this is
the fastest the we can expect. Just use the -o async flag on the
UFS mount. Good luck...
dangerous than the original MNT_ASYNC. There might be some minor
security considerations due to data writes not being posted as promptly
as before. Meta-data operations are still not quite as fast as Linux,
but streaming I/O is still higher.
filesystem layer, as was done in lite-2. Merged in some other cosmetic
changes while I was at it. Rewrote most of msdosfs_access() to be more
like ufs_access() and to include the FS read-only check.
Obtained from: partially from 4.4BSD-lite2
fix a change where a shortcut resulted in teh wrong answer..
e.g.
touch a
touch b
mv a b
resulted in b being removed and a being moved to b
in the shortcut..
touch a
ln a b
mv a b
the wrong link was removed..
leaving a instead of b, giving a different result to when
both files were separate.
bp->b_flags has been broken for many years:
a) they didn't set B_BUSY for doing i/o. This has been fatal since
1995/07/25 when biodone() started checking that B_BUSY is set.
b) they didn't set B_INVAL for releasing the buffer. This at best
just put a useless buffer in the LRU queue for a little while.
Fix a couple of spelling errors and complete a couple of function
pointer declarations.
Submitted by: terry (terry lambert)
This is a composite of 3 patch sets submitted by terry.
they are:
New low-level init code that supports loadbal modules better
some cleanups in the namei code to help terry in 16-bit character support
some changes to the mount-root code to make it a little more
modular..
NOTE: mounting root off cdrom or NFS MIGHT be broken as I haven't been able
to test those cases..
certainly mounting root of disk still works just fine..
mfs should work but is untested. (tomorrows task)
The low level init stuff includes a total rewrite of init_main.c
to make it possible for new modules to have an init phase by simply
adding an entry to a TEXT_SET (or is it DATA_SET) list. thus a new module can
be added to the kernel without editing any other files other than the
'files' file.
disksort is called at non-interrupt time and can be actively traversing
the list when that happens, there is a very small window of vulnerability.
Close it by protecting disksort with splbio().
wrong vp's ops vector being used by changing the VOP_LINK's argument order.
The special-case hack doesn't go far enough and breaks the generic
bypass routine used in some non-leaf filesystems. Pointed out by Kirk
McKusick.
proc or any VM system structure will have to be rebuilt!!!
Much needed overhaul of the VM system. Included in this first round of
changes:
1) Improved pager interfaces: init, alloc, dealloc, getpages, putpages,
haspage, and sync operations are supported. The haspage interface now
provides information about clusterability. All pager routines now take
struct vm_object's instead of "pagers".
2) Improved data structures. In the previous paradigm, there is constant
confusion caused by pagers being both a data structure ("allocate a
pager") and a collection of routines. The idea of a pager structure has
escentially been eliminated. Objects now have types, and this type is
used to index the appropriate pager. In most cases, items in the pager
structure were duplicated in the object data structure and thus were
unnecessary. In the few cases that remained, a un_pager structure union
was created in the object to contain these items.
3) Because of the cleanup of #1 & #2, a lot of unnecessary layering can now
be removed. For instance, vm_object_enter(), vm_object_lookup(),
vm_object_remove(), and the associated object hash list were some of the
things that were removed.
4) simple_lock's removed. Discussion with several people reveals that the
SMP locking primitives used in the VM system aren't likely the mechanism
that we'll be adopting. Even if it were, the locking that was in the code
was very inadequate and would have to be mostly re-done anyway. The
locking in a uni-processor kernel was a no-op but went a long way toward
making the code difficult to read and debug.
5) Places that attempted to kludge-up the fact that we don't have kernel
thread support have been fixed to reflect the reality that we are really
dealing with processes, not threads. The VM system didn't have complete
thread support, so the comments and mis-named routines were just wrong.
We now use tsleep and wakeup directly in the lock routines, for instance.
6) Where appropriate, the pagers have been improved, especially in the
pager_alloc routines. Most of the pager_allocs have been rewritten and
are now faster and easier to maintain.
7) The pagedaemon pageout clustering algorithm has been rewritten and
now tries harder to output an even number of pages before and after
the requested page. This is sort of the reverse of the ideal pagein
algorithm and should provide better overall performance.
8) Unnecessary (incorrect) casts to caddr_t in calls to tsleep & wakeup
have been removed. Some other unnecessary casts have also been removed.
9) Some almost useless debugging code removed.
10) Terminology of shadow objects vs. backing objects straightened out.
The fact that the vm_object data structure escentially had this
backwards really confused things. The use of "shadow" and "backing
object" throughout the code is now internally consistent and correct
in the Mach terminology.
11) Several minor bug fixes, including one in the vm daemon that caused
0 RSS objects to not get purged as intended.
12) A "default pager" has now been created which cleans up the transition
of objects to the "swap" type. The previous checks throughout the code
for swp->pg_data != NULL were really ugly. This change also provides
the rudiments for future backing of "anonymous" memory by something
other than the swap pager (via the vnode pager, for example), and it
allows the decision about which of these pagers to use to be made
dynamically (although will need some additional decision code to do
this, of course).
13) (dyson) MAP_COPY has been deprecated and the corresponding "copy
object" code has been removed. MAP_COPY was undocumented and non-
standard. It was furthermore broken in several ways which caused its
behavior to degrade to MAP_PRIVATE. Binaries that use MAP_COPY will
continue to work correctly, but via the slightly different semantics
of MAP_PRIVATE.
14) (dyson) Sharing maps have been removed. It's marginal usefulness in a
threads design can be worked around in other ways. Both #12 and #13
were done to simplify the code and improve readability and maintain-
ability. (As were most all of these changes)
TODO:
1) Rewrite most of the vnode pager to use VOP_GETPAGES/PUTPAGES. Doing
this will reduce the vnode pager to a mere fraction of its current size.
2) Rewrite vm_fault and the swap/vnode pagers to use the clustering
information provided by the new haspage pager interface. This will
substantially reduce the overhead by eliminating a large number of
VOP_BMAP() calls. The VOP_BMAP() filesystem interface should be
improved to provide both a "behind" and "ahead" indication of
contiguousness.
3) Implement the extended features of pager_haspage in swap_pager_haspage().
It currently just says 0 pages ahead/behind.
4) Re-implement the swap device (swstrategy) in a more elegant way, perhaps
via a much more general mechanism that could also be used for disk
striping of regular filesystems.
5) Do something to improve the architecture of vm_object_collapse(). The
fact that it makes calls into the swap pager and knows too much about
how the swap pager operates really bothers me. It also doesn't allow
for collapsing of non-swap pager objects ("unnamed" objects backed by
other pagers).
2) Removed unnecessary vm_object_lookup()/pager_cache(object, TRUE) pairs
after vnode_pager_alloc() calls - the object is already guaranteed to be
persistent.
3) Removed some gratuitous casts.
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
These changes solve the problem in a general way by moving the
initialization out of the individual fs_mountroot's and into swaponvp().
Submitted by: Poul-Henning Kamp
when the single user shell was terminated. These changes disallow mounting
or R/W upgrading filesystems that are dirty unless "-f" (force) option
is used with mount. /etc/rc has been modified to abort the startup if
one or more non-nfs partitions fail to mount.
Reviewed by: Poul-Henning Kamp, Rod Grimes
I ran into another manifestation of the problem reported in PR 211 and
fixed it. Try this:
as non-root:
cd /tmp; mkdir x y x/z
as root:
chown root /tmp/x/z
as non-root:
cd /tmp/x; mv z ../y # EACCES as expected
as root:
cd /tmp/x; mv z ../y # EINVAL NOT as expected
This is because ufs_rename() sets IN_RENAME and fails to clear it.
Reviewed by: davidg
Submitted by: bde
(2GB). If this limit is not imposed, then filesystem corruption will
ensue when files larger than 2GB are created. This is temporary,
and the underlying limitation will be removed later.
don't lock the vnode - it doesn't appear to ever be necessary for VCHR
vnode/inodes. This fixes a bug introduced in the previous commit that
caused tty timestamps to act strange (causing 'w' and 'finger' to show
the tty wasn't idle when it may have been for hours).
Fixed remaining known bugs in the buffer IO and VM system.
vfs_bio.c:
Fixed some race conditions and locking bugs. Improved performance
by removing some (now) unnecessary code and fixing some broken
logic.
Fixed process accounting of # of FS outputs.
Properly handle NFS interrupts (B_EINTR).
(various)
Replaced calls to clrbuf() with calls to an optimized routine
called vfs_bio_clrbuf().
(various FS sync)
Sync out modified vnode_pager backed pages.
ffs_vnops.c:
Do two passes: Sync out file data first, then indirect blocks.
vm_fault.c:
Fixed deadly embrace caused by acquiring locks in the wrong order.
vnode_pager.c:
Changed to use buffer I/O system for writing out modified pages. This
should fix the problem with the modification date previous not getting
updated. Also dramatically simplifies the code. Note that this is
going to change in the future and be implemented via VOP_PUTPAGES().
vm_object.c:
Fixed a pile of bugs related to cleaning (vnode) objects. The performance
of vm_object_page_clean() is terrible when dealing with huge objects,
but this will change when we implement a binary tree to keep the object
pages sorted.
vm_pageout.c:
Fixed broken clustering of pageouts. Fixed race conditions and other
lockup style bugs in the scanning of pages. Improved performance.
merged cache changes, and figure it out based on the B_VMIO buffer flag.
Fixes a problem where delayed write VMIO buffers would sometimes get
recopied into kernel-alloced memory.
Submitted by: John Dyson
during the FS sync. The system would appear to hang momentarily
if there was a large backlog of I/O. This is because the vnode
remains locked during the output - preventing normal character
I/O. The problem was exacerbated by the FFS contiguous block
allocation fixes and a semi-broken disksort(). The inode/date
will still be synced during a normal FS dismount and whenever
the inode is changed for other reasons.
allow Q_SYNC regardless of "target" uid, we allow it with -1;
fix bug that caused all ops to refer to user quotas, not group.
Submitted by: Mike Karels
if all free blocks are in the same bucket (i.e. NRPOS == 1).
Else a free block is choosen, possibly from a different cylinder,
even if the block succeeding bpref was free ...
Submitted by: se
mapping from numbers to names is messy for backwards compatibility.
E.g., for driver "sd", unit "0":
slice 0: omit the slice number for compatibility; names are sd0[a-h].
slice 1: omit the partition letter 'c' because the whole disk device
shouldn't have anything to do with partitions; sd0 is the
only name.
slices 2-31: subtract 1 from slice number to compensate for the
compatibility slice 0; names are sd0s[1-30][a-h].
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
ordering that can prove fatal during large batches of deletes, but this
is much better than it was. I probably won't be putting much more time
into this until Seltzer releases her new version of LFS which has
fragment support. This should be availible just before USENIX.
timestamps for an atomic operation such as rename() on a local file
system to be identical.
Uniformize yet another idempotency ifdef. The comment nesting was
bogus.
Allow chown() to return success if the gid isn't changed even if
the gid is not the caller's. Such gids are normal for files created
in world-writable directories sucj as /tmp. This "fixes" annoying
error messages for mv'ing files created in /tmp to another file
system. mv still preserves the foreign gid of /tmp, but now does
it silently.
buffering scheme and make it more in tune with FreeBSD's vfs_bio
implementation. The filesystem seems fairly stable, but I wouldn't recommend
it to anyone not willing to experience problems. This is very green code and
has the limitation that YOU CAN ONLY HAVE ONE LFS PARTITION MOUNTED AT A TIME.
What LFS is good for:
Non fsynced writes FASTER THAN FFS
Large deletions Increadibly fast
Reads are a little bit slower than FFS right now, but that is a factor of
how under optimized this code is. LFS should in theory perform at least as
well as FFS under fsync (iozone) type loads, and this is what I'm currently
working on.
Reviewed by: Justin Gibbs
Submitted by: John Dyson
Obtained from:
