so make the code slightly more uniform. The vnode lock is acquired in
all cases and now the only difference between VCHR and other is we
call UFS_UPDATE instead of VOP_FSYNC().
- Slightly rewrite the fsync loop to be more lock friendly. We must
acquire the vnode interlock before dropping the mnt lock. We must
also check XLOCK to prevent vclean() races.
- Use LK_INTERLOCK in the vget() in ffs_sync to further prevent vclean()
races.
- Use a local variable to store the results of the nvp == TAILQ_NEXT
test so that we do not access the vp after we've vrele()d it.
- Add an XXX comment about UFS_UPDATE() not being protected by any lock
here. I suspect that it should need the VOP lock.
we release the mntvnode_mtx.
- Call vgonel() directly instead of going through vrecycle() since we own
the interlock now.
- Remove a few cases where we locked the interlock just so that we could
call VOP_UNLOCK with interlock held.
in a list head instead of a pointer to the first element at the time of
the first call. These lists are subject to change, and getdirtybuf()
would refetch from the wrong list in some cases.
Spottedy by: tegge
Pointy hat to: me
bail out if the buffer is not already present.
- The buffer returned by incore() is not locked and should not be sent to
brelse(). Use getblk() with the new GB_NOCREAT flag to preserve the
desired semantics.
caller to acquire it. This permits drain_output() to be done atomically
with other operations as well as reducing the number of lock operations.
- Assert that the proper locks are held in drain_output().
- Change getdirtybuf() to accept a mutex as an argument. This mutex is used
to protect the vnode's buf list and the BKGRDWAIT flag. This lock is
dropped when we successfully acquire a buffer and held on return
otherwise. These semantics reduce the number of cumbersome cases in
calling code.
- Pass the mtx from getdirtybuf() into interlocked_sleep() and allow this
mutex to be used as the interlock argument to BUF_LOCK() in the LOCKBUF
case of interlocked_sleep().
- Change the return value of getdirtybuf() to be the resulting locked buffer
or NULL otherwise. This is for callers who pass in a list head that
requires a lock. It is necessary since the lock that protects the list
head must be dropped in getdirtybuf() so that we don't have a lock order
reversal with the buf queues lock in bremfree().
- Adjust all callers of getdirtybuf() to match the new semantics.
- Add a comment in indir_trunc() that points at unlocked access to a buf.
This may also be one of the last instances of incore() in the tree.
- Surround all accesses of the BKGRD{WAIT,INPROG} flags with the vnode
interlock.
- Don't use the B_LOCKED flag and QUEUE_LOCKED for background write
buffers. Check for the BKGRDINPROG flag before recycling or throwing
away a buffer. We do this instead because it is not safe for us to move
the original buffer to a new queue from the callback on the background
write buffer.
- Remove the B_LOCKED flag and the locked buffer queue. They are no longer
used.
- The vnode interlock is used around checks for BKGRDINPROG where it may
not be strictly necessary. If we hold the buf lock the a back-ground
write will not be started without our knowledge, one may only be
completed while we're not looking. Rather than remove the code, Document
two of the places where this extra locking is done. A pass should be
done to verify and minimize the locking later.
get the same value from ip->i_ump->um_devvp.
This saves a pointer in the memory copies of inodes, which can
easily run into several hundred kilobytes.
The extra indirection is unmeasurable in benchmarks.
Approved by: mckusick
kernel ACL interfaces and system call names.
Break out UFS2 and FFS extattr delete and list vnode operations from
setextattr and getextattr to deleteextattr and listextattr, which
cleans up the implementations, and makes the results more readable,
and makes the APIs more clear.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
contain the filedescriptor number on opens from userland.
The index is used rather than a "struct file *" since it conveys a bit
more information, which may be useful to in particular fdescfs and /dev/fd/*
For now pass -1 all over the place.
attribute name of "" from ffs_getextattr(). Invoking VOP_GETETATTR()
with an empty name is now no longer supported; user application
compatibility is provided by a system call level compatibility
wrapper. We make sure to explicitly reject attempts to set an EA
with the name "".
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
if we permit them to occur, the kernel panics due to our performing
EA operations using VOP_STRATEGY on the vnode. This went unnoticed
previously because there are very for users of device nodes on UFS2
due to the introduction of devfs. However, this can come up with
the Linux compat directories and its hard-coded dev nodes (which will
need to go away as we move away from hard-coded device numbers).
This can come up if you use EA-intensive features such as ACLs and
MAC.
The proper fix is pretty complicated, but this band-aid would be
an excellent MFC candidate for the release.
These fields can be left as NULL if ffs_vget() allocates an inode but
fails before the dinode memory has been allocated. There are two cases
when this can occur: when we lose a race and another process has added
the inode to the hash, and when reading the inode off disk fails.
The bug was observed by Kris on one of the package-building machines.
See http://marc.theaimsgroup.com/?l=freebsd-current&m=105172731013411&w=2
In Kris's case, it was the bread() that failed because of a disk error.
The alternative to this patch is to ensure that ffs_vget() does not call
vput() when the inode that hasn't been properly initialised.
kg_nice is now protected by both. Being protected by both means that
other places in the kernel that want to read kg_nice only need one of the
two locks.
requiring locked bufs in vfs_bio_awrite(). Previously the buf could
have been written out by fsync before we acquired the buf lock if it
weren't for giant. The cluster_wbuild() handles this race properly but
the single write at the end of vfs_bio_awrite() would not.
- Modify flushbufqueues() so there is only one copy of the loop. Pass a
parameter in that says whether or not we should sync bufs with deps.
- Call flushbufqueues() a second time and then break if we couldn't find
any bufs without deps.
of a snapshot's copy of a superblock. This patch fixes a panic
when taking a snapshot of a 4096/512 filesystem.
Reported by: Ian Freislich <ianf@za.uu.net>
Sponsored by: DARPA & NAI Labs.
- Define one flag GB_LOCK_NOWAIT that tells getblk() to pass the LK_NOWAIT
flag to the initial BUF_LOCK(). This will eventually be used in cases
were we want to use a buffer only if it is not currently in use.
- Convert all consumers of the getblk() api to use this extra parameter.
Reviwed by: arch
Not objected to by: mckusick
from the filesystem size field to the filesystem maximum blocksize
field. The problem is that older versions of growfs updated only the
new size field and not the old size field. This resulted in the old
(smaller) size field being copied up to the new size field which
caused the filesystem to appear to fsck to be badly trashed.
This also adds a sanity check to ensure that the superblock is not
being updated when the filesystem is mounted read-only. Obviously
such an update should never happen.
Reported by: Nate Lawson <nate@root.org>
Sponsored by: DARPA & NAI Labs.
- Remove the buftimelock mutex and acquire the buf's interlock to protect
these fields instead.
- Hold the vnode interlock while locking bufs on the clean/dirty queues.
This reduces some cases from one BUF_LOCK with a LK_NOWAIT and another
BUF_LOCK with a LK_TIMEFAIL to a single lock.
Reviewed by: arch, mckusick
a snapshot. As part of taking a snapshot of a filesystem, the kernel
builds up a list of the filesystem metadata (such as the cylinder
group bitmaps) that are contained in the snapshot. When doing a
copy-on-write check, the list is first consulted. If the block being
written is found on the list, then the full snapshot lookup can be
avoided. Besides providing an important performance speedup this
check also avoids a potential deadlock between the code creating
the snapshot and the bufdaemon trying to cleanup snapshot related
buffers. This fix creates a temporary list containing the key
metadata blocks that can cause the deadlock. This temporary list
is used between the time that the snapshot is first enabled and the
time that the fully complete list is built.
Reported by: Attila Nagy <bra@fsn.hu>
Sponsored by: DARPA & NAI Labs.
is being taken from panicing with either "freeing free block" or
"freeing free inode". The problem arises when the snapshot code
is scanning the filesystem looking for inodes with a reference
count of zero (e.g., unlinked but still open) so that it can
expunge them from its view. If it encounters a reclaimed vnode
and has to restart its scan, then it will panic if it encounters
and tries to free an inode that it has already processed. The fix
is to check each candidate inode to see if it has already been
processed before trying to delete it from the snapshot image.
Sponsored by: DARPA & NAI Labs.
that they convert to 64-bit values before shifting rather than
afterwards. Once fixed, they can be used rather than inline expanded.
Sponsored by: DARPA & NAI Labs.
values for the initial inode generation numbers in newfs and for
newly allocated inode generation numbers in the kernel.
Submitted by: Theo de Raadt <deraadt@cvs.openbsd.org>
Sponsored by: DARPA & NAI Labs.
that is protected by the vnode lock.
- Move B_SCANNED into b_vflags and call it BV_SCANNED.
- Create a vop_stdfsync() modeled after spec's sync.
- Replace spec_fsync, msdos_fsync, and hpfs_fsync with the stdfsync and some
fs specific processing. This gives all of these filesystems proper
behavior wrt MNT_WAIT/NOWAIT and the use of the B_SCANNED flag.
- Annotate the locking in buf.h
pointer types, and remove a huge number of casts from code using it.
Change struct xfile xf_data to xun_data (ABI is still compatible).
If we need to add a #define for f_data and xf_data we can, but I don't
think it will be necessary. There are no operational changes in this
commit.
padding is not specific to non-i386 architectures. It is
caused by non-i386 specific alignment requirements of
fs_swuid,
o Add a CTASSERT to catch a change in the size of struct fs
at compile-time rather than run-time.
Ok'd: gordon
Tested on: i386 ia64
will be used to support volume names with the help of a GEOM module (to be
committed). uuid will be used to deal with conflicting volume names (which
doesn't work just yet).
Approved by: mckusick@
repeatedly truncate the same file. Each time the file is truncated,
a buffer is grabbed to store the indirect block numbers that need
to be freed. Those blocks cannot be freed until the inode claiming
them is written to disk. Thus, the number of buffers being held by
soft updates explodes and in extreme cases can run the kernel out
of buffers. The problem can be avoided by doing an fsync on the
file every debug.maxindirdep truncates (currently defaulted to 50).
The fsync causes the inode to be written so that the held buffers
can be freed. The check for excessive buffers is checked as part
of the existing hook for excessive dependencies (softdep_slowdown)
in the truncate code.
Reported by: David Schultz <dschultz@uclink.Berkeley.EDU>
Sponsored by: DARPA & NAI Labs.
MFC after: 3 weeks
this was causing filedesc work to be very painful.
In order to make this work split out sigio definitions to thier own header
(sigio.h) which is included from proc.h for the time being.
Remove the malloctype from the ufs mount structure, instead add a callback
to the storage method for freeing inodes: UFS_IFREE().
Add vfs_ifree() method function which frees an inode.
Unvariablelize the malloc type used for allocating inodes.
so as to work correctly on 64-bit platforms.
Reported-by: Jake Burkholder <jake@locore.ca>
Sponsored by: DARPA & NAI Labs.
Approved by: Ian Dowse <iedowse@maths.tcd.ie>
that were copied in all of the earlier snapshots, thus its precomputed
list must be used in the copyonwrite test. Using incomplete lists may
lead to deadlock. Also do not include the blocks used for the indirect
pointers in the indirect pointers as this may lead to inconsistent
snapshots.
Sponsored by: DARPA & NAI Labs.
Approved by: re
previously allocated block as the previous use of the block may
have fallen out of the cache. Failure to reread its contents cause
zeroed results to be written instead of the proper contents.
Conversely, when the block is going to be entirely filled in, it
is not necessary reread the old contents.
Sponsored by: DARPA & NAI Labs.
Approved by: re
converting from individual vnode locks to the snapshot
lock, be sure to pass any waiting processes along to the
new lock as well. This transfer is done by a new function
in the lock manager, transferlockers(from_lock, to_lock);
Thanks to Lamont Granquist <lamont@scriptkiddie.org> for
his help in pounding on snapshots beyond all reason and
finding this deadlock.
Sponsored by: DARPA & NAI Labs.
1) Release the snapshot file lock while suspending the system. Otherwise
a process trying to read the lock may block on its containing directory
preventing the suspension from completing. Thanks to Sean Kelly
<smkelly@zombie.org> for finding this deadlock.
2) Replace some bdwrite's with bawrite's so as not to fill all the
buffers with dirty data. The buffers could not be cleaned as the
snapshot vnode was locked hence the system could deadlock when
making snapshots of really massive filesystems. Thanks to
Hidetoshi Shimokawa <simokawa@sat.t.u-tokyo.ac.jp> for figuring
this out.
Sponsored by: DARPA & NAI Labs.
before using it to write the superblock. This is to guard against
accidentally trashing the disklabel if the superblock format missed
being upgraded by the new kernel.
Reported by: Sam Leffler <sam@errno.com>
Sponsored by: DARPA & NAI Labs.
Approved by: Murray Stokely <murray@FreeBSD.org>
the old 8-bit fs_old_flags to the new location the first time that the
filesystem is mounted by a new kernel. One of the unused flags in
fs_old_flags is used to indicate that the flags have been moved.
Leave the fs_old_flags word intact so that it will work properly if
used on an old kernel.
Change the fs_sblockloc superblock location field to be in units
of bytes instead of in units of filesystem fragments. The old units
did not work properly when the fragment size exceeeded the superblock
size (8192). Update old fs_sblockloc values at the same time that
the flags are moved.
Suggested by: BOUWSMA Barry <freebsd-misuser@netscum.dyndns.dk>
Sponsored by: DARPA & NAI Labs.
in half because of reports that under heavy load the kernel could
exhaust its memory pool. The limit is now (desiredvnodes * 4)
rather than (desiredvnodes * 8), so it will still scale with
larger systems, just not as quickly.
Sponsored by: DARPA & NAI Labs.
not have hit the disk and the dependencies cannot be unrolled.
In this case, the system will mark the buffer as dirty again so
that the write can be retried in the future. When the write
succeeds or the system gives up on the buffer and marks it as
invalid (B_INVAL), the dependencies will be cleared.
Sponsored by: DARPA & NAI Labs.
"refreshing" the label on the vnode before use, just get the label
right from inception. For single-label file systems, set the label
in the generic VFS getnewvnode() code; for multi-label file systems,
leave the labeling up to the file system. With UFS1/2, this means
reading the extended attribute during vfs_vget() as the inode is
pulled off disk, rather than hitting the extended attributes
frequently during operations later, improving performance. This
also corrects sematics for shared vnode locks, which were not
previously present in the system. This chances the cache
coherrency properties WRT out-of-band access to label data, but in
an acceptable form. With UFS1, there is a small race condition
during automatic extended attribute start -- this is not present
with UFS2, and occurs because EAs aren't available at vnode
inception. We'll introduce a work around for this shortly.
Approved by: re
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
check for and/or report I/O errors. The result is that a VFS_SYNC
or VOP_FSYNC called with MNT_WAIT could loop infinitely on ufs in
the presence of a hard error writing a disk sector or in a filesystem
full condition. This patch ensures that I/O errors will always be
checked and returned. This patch also ensures that every call to
VFS_SYNC or VOP_FSYNC with MNT_WAIT set checks for and takes
appropriate action when an error is returned.
Sponsored by: DARPA & NAI Labs.
the ffs_copyonwrite routine to avoid a deadlock between the syncer
daemon trying to sync out a snapshot vnode and the bufdaemon
trying to write out a buffer containing the snapshot inode.
With any luck this will be the last snapshot race condition.
Sponsored by: DARPA & NAI Labs.
a full filesystem. Previously, if the allocation failed, we had to
fsync the file before rolling back any partial allocation of indirect
blocks. Most block allocation requests only need to allocate a single
data block and if that allocation fails, there is nothing to unroll.
So, before doing the fsync, we check to see if any rollback will
really be necessary. If none is necessary, then we simply return.
This update eliminates the flurry of disk activity that got triggered
whenever a filesystem would run out of space.
Sponsored by: DARPA & NAI Labs.
that works in the new threaded kernel. It was commented out of
the disksort routine earlier this year for the reasons given in
kern/subr_disklabel.c (which is where this code used to reside
before it moved to kern/subr_disk.c):
----------------------------
revision 1.65
date: 2002/04/22 06:53:20; author: phk; state: Exp; lines: +5 -0
Comment out Kirks io-request priority hack until we can do this in a
civilized way which doesn't cause grief.
The problem is that it is not generally safe to cast a "struct bio
*" to a "struct buf *". Things like ccd, vinum, ata-raid and GEOM
constructs bio's which are not entrails of a struct buf.
Also, curthread may or may not have anything to do with the I/O request
at hand.
The correct solution can either be to tag struct bio's with a
priority derived from the requesting threads nice and have disksort
act on this field, this wouldn't address the "silly-seek syndrome"
where two equal processes bang the diskheads from one edge to the
other of the disk repeatedly.
Alternatively, and probably better: a sleep should be introduced
either at the time the I/O is requested or at the time it is completed
where we can be sure to sleep in the right thread.
The sleep also needs to be in constant timeunits, 1/hz can be practicaly
any sub-second size, at high HZ the current code practically doesn't
do anything.
----------------------------
As suggested in this comment, it is no longer located in the disk sort
routine, but rather now resides in spec_strategy where the disk operations
are being queued by the thread that is associated with the process that
is really requesting the I/O. At that point, the disk queues are not
visible, so the I/O for positively niced processes is always slowed
down whether or not there is other activity on the disk.
On the issue of scaling HZ, I believe that the current scheme is
better than using a fixed quantum of time. As machines and I/O
subsystems get faster, the resolution on the clock also rises.
So, ten years from now we will be slowing things down for shorter
periods of time, but the proportional effect on the system will
be about the same as it is today. So, I view this as a feature
rather than a drawback. Hence this patch sticks with using HZ.
Sponsored by: DARPA & NAI Labs.
Reviewed by: Poul-Henning Kamp <phk@critter.freebsd.dk>
of a file in chunks that are less then the filesystem block size, if the
data is not already cached the system will perform a read-before-write.
The problem is that it does this on a block-by-block basis, breaking up the
I/Os and making clustering impossible for the writes. Programs such
as INN using cyclic file buffers suffer greatly. This problem is only going
to get worse as we use larger and larger filesystem block sizes.
The solution is to extend the sequential heuristic so UFS[2] can perform
a far larger read and readahead when dealing with this case.
(note: maximum disk write bandwidth is 27MB/sec thru filesystem)
(note: filesystem blocksize in test is 8K (1K frag))
dd if=/dev/zero of=test.dat bs=1k count=2m conv=notrunc
Before: (note half of these are reads)
tty da0 da1 acd0 cpu
tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id
0 76 14.21 598 8.30 0.00 0 0.00 0.00 0 0.00 0 0 7 1 92
0 76 14.09 813 11.19 0.00 0 0.00 0.00 0 0.00 0 0 9 5 86
0 76 14.28 821 11.45 0.00 0 0.00 0.00 0 0.00 0 0 8 1 91
After: (note half of these are reads)
tty da0 da1 acd0 cpu
tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id
0 76 63.62 434 26.99 0.00 0 0.00 0.00 0 0.00 0 0 18 1 80
0 76 63.58 424 26.30 0.00 0 0.00 0.00 0 0.00 0 0 17 2 82
0 76 63.82 438 27.32 0.00 0 0.00 0.00 0 0.00 1 0 19 2 79
Reviewed by: mckusick
Approved by: re
X-MFC after: immediately (was heavily tested in -stable for 4 months)
a common lock. This change avoids a deadlock between snapshots when
separate requests cause them to deadlock checking each other for a
need to copy blocks that are close enough together that they fall
into the same indirect block. Although I had anticipated a slowdown
from contention for the single lock, my filesystem benchmarks show
no measurable change in throughput on a uniprocessor system with
three active snapshots. I conjecture that this result is because
every copy-on-write fault must check all the active snapshots, so
the process was inherently serial already. This change removes the
last of the deadlocks of which I am aware in snapshots.
Sponsored by: DARPA & NAI Labs.
automatically set MNT_MULTILABEL in the mount flags.
If FS_ACLS is set in a UFS or UFS2 superblock, automatically
set MNT_ACLS in the mount flags.
If either of these flags is set, but the appropriate kernel option
to support the features associated with the flag isn't available,
then print a warning at mount-time.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
or fifo in UFS2, the normal ufs_strategy routine needs to be used
rather than the spec_strategy or fifo_strategy routine. Thus the
ffsext_strategy routine is interposed in the ffs_vnops vectors for
special devices and fifo's to pick off this special case. Otherwise
it simply falls through to the usual spec_strategy or fifo_strategy
routine.
Submitted by: Robert Watson <rwatson@FreeBSD.org>
Sponsored by: DARPA & NAI Labs.
FS_ACLS Administrative enable/disable of extended ACL support
FS_MULTILABEL Administrative flag to indicate to the MAC Framework
that objects in the file system are individually
labeled using extended attributes.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
Reviewed by: (in principal) mckusick, phk
that use it. Specifically, vop_stdlock uses the lock pointed to by
vp->v_vnlock. By default, getnewvnode sets up vp->v_vnlock to
reference vp->v_lock. Filesystems that wish to use the default
do not need to allocate a lock at the front of their node structure
(as some still did) or do a lockinit. They can simply start using
vn_lock/VOP_UNLOCK. Filesystems that wish to manage their own locks,
but still use the vop_stdlock functions (such as nullfs) can simply
replace vp->v_vnlock with a pointer to the lock that they wish to
have used for the vnode. Such filesystems are responsible for
setting the vp->v_vnlock back to the default in their vop_reclaim
routine (e.g., vp->v_vnlock = &vp->v_lock).
In theory, this set of changes cleans up the existing filesystem
lock interface and should have no function change to the existing
locking scheme.
Sponsored by: DARPA & NAI Labs.
Whenever doing a copy-on-write check, first look in the list of
initially allocated blocks to see if it is there. If so, no further
check is needed. If not, fall through and do the full check. This
change eliminates one of two known deadlocks caused by snapshots.
Handling the second deadlock will be the subject of another check-in.
This change also reduces the cost of the copy-on-write check by
speeding up the verification of frequently checked blocks.
Sponsored by: DARPA & NAI Labs.
even when the underlying device has a larger sector size. Therefore,
the filesystem code should not (and with this patch does not) try to
use the underlying sector size when doing disk block address calculations.
This patch fixes problems in -current when using the swap-based
memory-disk device (mdconfig -a -t swap ...). This bugfix is not
relevant to -stable as -stable does not have the memory-disk device.
Sponsored by: DARPA & NAI Labs.
v_tag is now const char * and should only be used for debugging.
Additionally:
1. All users of VT_NTS now check vfsconf->vf_type VFCF_NETWORK
2. The user of VT_PROCFS now checks for the new flag VV_PROCDEP, which
is propagated by pseudofs to all child vnodes if the fs sets PFS_PROCDEP.
Suggested by: phk
Reviewed by: bde, rwatson (earlier version)
layers deep in <sys/proc.h> or <sys/vnode.h>.
Include <sys/vmmeter.h> instead of depending on namespace pollution in
<sys/pcpu.h>.
Sorted includes as much as possible.
pmap_zero_page() and pmap_zero_page_area() were modified to accept
a struct vm_page * instead of a physical address, vm_page_zero_fill()
and vm_page_zero_fill_area() have served no purpose.
parts rather than use vop_{read,write}_args. Access to these
functions will ultimately not be available through the
"vop_{read,write}+IO_EXT" API but this functionality is retained
for debugging purposes for now.
Sponsored by: DARPA & NAI Labs.
UFS only thing, and FFS should in principle not know if it is enabled
or not.
This commit cleans ffs_vnops.c for such knowledge, but not ffs_vfsops.c
Sponsored by: DARPA and NAI Labs.
these in the main filesystems. This does not change the resulting code
but makes the source a little bit more grepable.
Sponsored by: DARPA and NAI Labs.
- v_vflag is protected by the vnode lock and is used when synchronization
with VOP calls is needed.
- v_iflag is protected by interlock and is used for dealing with vnode
management issues. These flags include X/O LOCK, FREE, DOOMED, etc.
- All accesses to v_iflag and v_vflag have either been locked or marked with
mp_fixme's.
- Many ASSERT_VOP_LOCKED calls have been added where the locking was not
clear.
- Many functions in vfs_subr.c were restructured to provide for stronger
locking.
Idea stolen from: BSD/OS
As this code is not actually used by any of the existing
interfaces, it seems unlikely to break anything (famous
last words).
The internal kernel interface to manipulate these attributes
is invoked using two new IO_ flags: IO_NORMAL and IO_EXT.
These flags may be specified in the ioflags word of VOP_READ,
VOP_WRITE, and VOP_TRUNCATE. Specifying IO_NORMAL means that
you want to do I/O to the normal data part of the file and
IO_EXT means that you want to do I/O to the extended attributes
part of the file. IO_NORMAL and IO_EXT are mutually exclusive
for VOP_READ and VOP_WRITE, but may be specified individually
or together in the case of VOP_TRUNCATE. For example, when
removing a file, VOP_TRUNCATE is called with both IO_NORMAL
and IO_EXT set. For backward compatibility, if neither IO_NORMAL
nor IO_EXT is set, then IO_NORMAL is assumed.
Note that the BA_ and IO_ flags have been `merged' so that they
may both be used in the same flags word. This merger is possible
by assigning the IO_ flags to the low sixteen bits and the BA_
flags the high sixteen bits. This works because the high sixteen
bits of the IO_ word is reserved for read-ahead and help with
write clustering so will never be used for flags. This merge
lets us get away from code of the form:
if (ioflags & IO_SYNC)
flags |= BA_SYNC;
For the future, I have considered adding a new field to the
vattr structure, va_extsize. This addition could then be
exported through the stat structure to allow applications to
find out the size of the extended attribute storage and also
would provide a more standard interface for truncating them
(via VOP_SETATTR rather than VOP_TRUNCATE).
I am also contemplating adding a pathconf parameter (for
concreteness, lets call it _PC_MAX_EXTSIZE) which would
let an application determine the maximum size of the extended
atribute storage.
Sponsored by: DARPA & NAI Labs.
direct calls for the two places where the kernel calls into soft
updates code. Set up the hooks in softdep_initialize() and NULL
them out in softdep_uninitialize(). This change allows soft updates
to function correctly when ufs is loaded as a module.
Reviewed by: mckusick
module. This adds an ffs_uninit() function that calls ufs_uninit()
and also calls a new softdep_uninitialize() function. Add a stub
for softdep_uninitialize() to cover the non-SOFTUPDATES case.
Reviewed by: mckusick
imposed by the filesystem structure itself remains. With 16k blocks,
the maximum file size is now just over 128TB.
For now, the UFS1 file size limit is left unchanged so as to remain
consistent with RELENG_4, but it too could be removed in the future.
Reviewed by: mckusick
out of inodes in a cylinder group would fail to check for
free inodes in other cylinder groups. This bug was introduced
in the UFS2 code merge two days ago.
An inode is allocated by calling ffs_valloc which calls
ffs_hashalloc to do the filesystem scan. Ffs_hashalloc
walks around the cylinder groups calling its passed allocator
(ffs_nodealloccg in this case) until the allocator returns a
non-zero result. The bug is that ffs_hashalloc expects the
passed allocator function to return a 64-bit ufs2_daddr_t.
When allocating inodes, it calls ffs_nodealloccg which was
returning a 32-bit ino_t. The ffs_hashalloc code checked
a 64-bit return value and usually found random non-zero bits in
the high 32-bits so decided that the allocation had succeeded
(in this case in the only cylinder group that it checked).
When the result was passed back to ffs_valloc it looked at
only the bottom 32-bits, saw zero and declared the system
out of inodes. But ffs_hashalloc had really only checked
one cylinder group.
The fix is to change ffs_nodealloccg to return 64-bit results.
Sponsored by: DARPA & NAI Labs.
Submitted by: Poul-Henning Kamp <phk@critter.freebsd.dk>
Reviewed by: Maxime Henrion <mux@freebsd.org>
filesystem expands the inode to 256 bytes to make space for 64-bit
block pointers. It also adds a file-creation time field, an ability
to use jumbo blocks per inode to allow extent like pointer density,
and space for extended attributes (up to twice the filesystem block
size worth of attributes, e.g., on a 16K filesystem, there is space
for 32K of attributes). UFS2 fully supports and runs existing UFS1
filesystems. New filesystems built using newfs can be built in either
UFS1 or UFS2 format using the -O option. In this commit UFS1 is
the default format, so if you want to build UFS2 format filesystems,
you must specify -O 2. This default will be changed to UFS2 when
UFS2 proves itself to be stable. In this commit the boot code for
reading UFS2 filesystems is not compiled (see /sys/boot/common/ufsread.c)
as there is insufficient space in the boot block. Once the size of the
boot block is increased, this code can be defined.
Things to note: the definition of SBSIZE has changed to SBLOCKSIZE.
The header file <ufs/ufs/dinode.h> must be included before
<ufs/ffs/fs.h> so as to get the definitions of ufs2_daddr_t and
ufs_lbn_t.
Still TODO:
Verify that the first level bootstraps work for all the architectures.
Convert the utility ffsinfo to understand UFS2 and test growfs.
Add support for the extended attribute storage. Update soft updates
to ensure integrity of extended attribute storage. Switch the
current extended attribute interfaces to use the extended attribute
storage. Add the extent like functionality (framework is there,
but is currently never used).
Sponsored by: DARPA & NAI Labs.
Reviewed by: Poul-Henning Kamp <phk@freebsd.org>
vnode creation globaly, we allow processes to create vnodes concurently.
In case of concurent creation of vnode for the one ino, we allow processes
to race and then check who wins.
Assuming that concurent creation of vnode for same ino is really rare case,
this is belived to be an improvement, as it just allows concurent creation
of vnodes.
Idea by: bp
Reviewed by: dillon
MFC after: 1 month
most cases NULL is passed, but in some cases such as network driver locks
(which use the MTX_NETWORK_LOCK macro) and UMA zone locks, a name is used.
Tested on: i386, alpha, sparc64
general cleanup of the API. The entire API now consists of two functions
similar to the pre-KSE API. The suser() function takes a thread pointer
as its only argument. The td_ucred member of this thread must be valid
so the only valid thread pointers are curthread and a few kernel threads
such as thread0. The suser_cred() function takes a pointer to a struct
ucred as its first argument and an integer flag as its second argument.
The flag is currently only used for the PRISON_ROOT flag.
Discussed on: smp@
provided the latter is nonzero. At this point, the former is a fairly
arbitrary default value (DFTPHYS), so changing it to any reasonable
value specified by the device driver is safe. Using the maximum of
these limits broke ffs clustered i/o for devices whose si_iosize_max
is < DFLTPHYS. Using the minimum would break device drivers' ability
to increase the active limit from DFTLPHYS up to MAXPHYS.
Copied the code for this and the associated (unnecessary?) fixup of
mp_iosize_max to all other filesystems that use clustering (ext2fs and
msdosfs). It was completely missing.
PR: 36309
MFC-after: 1 week
locking flags when acquiring a vnode. The immediate purpose is
to allow polling lock requests (LK_NOWAIT) needed by soft updates
to avoid deadlock when enlisting other processes to help with
the background cleanup. For the future it will allow the use of
shared locks for read access to vnodes. This change touches a
lot of files as it affects most filesystems within the system.
It has been well tested on FFS, loopback, and CD-ROM filesystems.
only lightly on the others, so if you find a problem there, please
let me (mckusick@mckusick.com) know.
the bio and buffer structures to have daddr64_t bio_pblkno,
b_blkno, and b_lblkno fields which allows access to disks
larger than a Terabyte in size. This change also requires
that the VOP_BMAP vnode operation accept and return daddr64_t
blocks. This delta should not affect system operation in
any way. It merely sets up the necessary interfaces to allow
the development of disk drivers that work with these larger
disk block addresses. It also allows for the development of
UFS2 which will use 64-bit block addresses.
read-only.
The trouble here is that we don't reopen the device in read/write mode
when we remount in read/write mode resulting in a filesystem sending
write requests to a device which was only opened read/only.
I'm not quite sure how such a reopen would best be done and defer
the problem to more agile hackers.
and isn't strictly required. However, it lowers the number of false
positives found when grep'ing the kernel sources for p_ucred to ensure
proper locking.
inode'' panic. This change corrects that problem by setting the
fs_active flag when the inode map changes to notify the snapshot
code that the cylinder group must be rescanned.
Submitted by: Robert Watson <rwatson@FreeBSD.org>
without being reclaimed. This bug was introduced in revision 1.95
dealing with filenames placed in newly allocated directory blocks,
thus is not present in 4.X systems. The bug is triggered when a
new entry is made in a directory after the data block containing
the original new entry has been written, but before the inode
that references the data block has been written.
Submitted by: Bill Fenner <fenner@research.att.com>
been unlinked (e.g., with a zero link count). We have to expunge
all trace of these files from the snapshot so that they are neither
reclaimed prematurely by fsck nor saved unnecessarily by dump.
which small and/or nearly full filesystems would fail with `file
system full' messages when trying to replace a number of existing
files (for example during a system installation). When the allocation
routines are about to fail with a file system full condition, they
make a call to softdep_request_cleanup() which attempts to accelerate
the flushing of pending deletion requests in an effort to free up
space. In the face of filesystem I/O requests that exceed the
available disk transfer capacity, the cleanup request could take
an unbounded amount of time. Thus, the softdep_request_cleanup()
routine will only try for tickdelay seconds (default 2 seconds)
before giving up and returning a filesystem full error. Under typical
conditions, the softdep_request_cleanup() routine is able to free
up space in under fifty milliseconds.
which caused incomplete snapshots to be taken. When background
fsck would run on these snapshots, the result would be files
being incorrectly released which would subsequently panic the
kernel with ``handle_workitem_freefile: inodedep survived'',
``handle_written_inodeblock: live inodedep'', and
``handle_workitem_remove: lost inodedep'' errors.
involving file removal or file update were not always being fully
committed to disk. The result was lost files or corrupted file data.
This change ensures that the filesystem is properly synced to disk
before the filesystem is down-graded.
This delta also fixes a long standing bug in which a file open for
reading has been unlinked. When the last open reference to the file
is closed, the inode is reclaimed by the filesystem. Previously,
if the filesystem had been down-graded to read-only, the inode could
not be reclaimed, and thus was lost and had to be later recovered
by fsck. With this change, such files are found at the time of the
down-grade. Normally they will result in the filesystem down-grade
failing with `device busy'. If a forcible down-grade is done, then
the affected files will be revoked causing the inode to be released
and the open file descriptors to begin failing on attempts to read.
Submitted by: "Sam Leffler" <sam@errno.com>
Seigo Tanimura (tanimura) posted the initial delta.
I've polished it quite a bit reducing the need for locking and
adapting it for KSE.
Locks:
1 mutex in each filedesc
protects all the fields.
protects "struct file" initialization, while a struct file
is being changed from &badfileops -> &pipeops or something
the filedesc should be locked.
1 mutex in each struct file
protects the refcount fields.
doesn't protect anything else.
the flags used for garbage collection have been moved to
f_gcflag which was the FILLER short, this doesn't need
locking because the garbage collection is a single threaded
container.
could likely be made to use a pool mutex.
1 sx lock for the global filelist.
struct file * fhold(struct file *fp);
/* increments reference count on a file */
struct file * fhold_locked(struct file *fp);
/* like fhold but expects file to locked */
struct file * ffind_hold(struct thread *, int fd);
/* finds the struct file in thread, adds one reference and
returns it unlocked */
struct file * ffind_lock(struct thread *, int fd);
/* ffind_hold, but returns file locked */
I still have to smp-safe the fget cruft, I'll get to that asap.
lost if some other process uses the lock while we are sleeping. We
restore it after we have slept. This functionality is provided by
a new routine interlocked_sleep() that wraps the interlocking with
functions that sleep. This function is then used in place of the
old ACQUIRE_LOCK_INTERLOCKED() and FREE_LOCK_INTERLOCKED() macros.
Submitted by: Debbie Chu <dchu@juniper.net>
in softdep_sync_metadata(). Otherwise we may miss dependencies
that need to be flushed which will result in a later panic
with the message ``vinvalbuf: dirty bufs''.
Submitted by: Matthew Dillon <dillon@apollo.backplane.com>
MFC after: 1 week
against VM_WAIT in the pageout code. Both fixes involve adjusting
the lockmgr's timeout capability so locks obtained with timeouts do not
interfere with locks obtained without a timeout.
Hopefully MFC: before the 4.5 release
superblock that is already set up to handle pointer types. This
fixes an accidental change in the superblock size on 64-bit platforms
caused by revision 1.24.
when taking a snapshot. The two time consuming operations are
scanning all the filesystem bitmaps to determine which blocks
are in use and scanning all the other snapshots so as to be able
to expunge their blocks from the view of the current snapshot.
The bitmap scanning is broken into two passes. Before suspending
the filesystem all bitmaps are scanned. After the suspension,
those bitmaps that changed after being scanned the first time
are rescanned. Typically there are few bitmaps that need to be
rescanned. The expunging of other snapshots is now done after
the suspension is released by observing that we can easily
identify any blocks that were allocated to them after the
suspension (they will be maked as `not needing to be copied'
in the just created snapshot). For all the gory details, see
the ``Running fsck in the Background'' paper in the Usenix
BSDCon 2002 Conference Proceedings, pages 55-64.
new file end will land in the middle of a file hole. Since the last
block of a file must always be allocated, the hole is filled by
allocating a block at that location. If the hole being filled is
a direct block, then the truncation may eventually reduce the
full sized block down to a fragment. When running with soft
updates, it is necessary to FSYNC the file after allocating the
block and before creating the fragment to avoid triggering a
soft updates inconsistency when the block unexpectedly shrinks.
Found by: Matthew Dillon <dillon@apollo.backplane.com>
MFC after: 1 week
real effect.
Optimize vfs_msync(). Avoid having to continually drop and re-obtain
mutexes when scanning the vnode list. Improves looping case by 500%.
Optimize ffs_sync(). Avoid having to continually drop and re-obtain
mutexes when scanning the vnode list. This makes a couple of assumptions,
which I believe are ok, in regards to vnode stability when the mount list
mutex is held. Improves looping case by 500%.
(more optimization work is needed on top of these fixes)
MFC after: 1 week
- Move the SPECIAL_FLAG #define up next to the NOHOLDER #define and fix a
little nit that caused it to be defined as -(sizeof (struct thread) + 1)
instead of -2.
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.
Sorry john! (your next MFC will be a doosie!)
Reviewed by: peter@freebsd.org, dillon@freebsd.org
X-MFC after: ha ha ha ha
an array "fs_contigdirs[]" to avoid too many directories getting
created in each cylinder group. The memory required for this and
two other arrays (fs_csp[] and fs_maxcluster[]) is allocated with
a single malloc() call, and divided up afterwards. However, the
'space' pointer is not advanced correctly, so fs_contigdirs and
fs_maxcluster end up pointing to the same address.
Add the missing code to advance the 'space' pointer, and remove
an unnecessary update of the pointer that follows.
This is likely to fix the "ffs_clusteralloc: map mismatch" panics
that have been reported recently.
Submitted by: Luke Mewburn <lukem@wasabisystems.com>
in got a bit broken, when ufs_extattr_stop() was called and failed,
ufs_extattr_destroy() would panic. This makes the call to destroy()
conditional on the success of stop().
Submitted by: Christian Carstensen <cc@devcon.net>
Obtained from: TrustedBSD Project
The symptom being treated in 1.98 was to avoid freeing a
pagedep dependency if there was still a newdirblk dependency
referencing it. That change is correct and no longer prints
a warning message when it occurs. The other part of revision
1.98 was to panic when a newdirblk dependency was encountered
during a file truncation. This fix removes that panic and
replaces it with code to find and delete the newdirblk
dependency so that the truncation can succeed.
incorrect due to a missing check for some dependency. This change
avoids the freelist corruption (but not the temporarily inconsistent
state of the file system).
A message is printed as a reminder of the under lying problem when a
pagedep structure is not freed due to the NEWBLOCK flag being set.
Submitted by: Tor.Egge@fast.no
committed to disk before clearing them. More specifically, when
free_newdirblk is called, we know that the inode claims the new
directory block. However, if the associated pagedep is still linked
onto the directory buffer dependency chain, then some of the entries
on the pd_pendinghd list may not be committed to disk yet. In this
case, we will simply note that the inode claims the block and let
the pd_pendinghd list be processed when the pagedep is next written.
If the pagedep is no longer on the buffer dependency chain, then
all the entries on the pd_pending list are committed to disk and
we can free them in free_newdirblk. This corrects a window of
vulnerability introduced in the code added in version 1.95.
whose name is within that block must ensure not only that the block
containing the file name has been written, but also that the on-disk
directory inode references that block. When a new directory block
is created, we allocate a newdirblk structure which is linked to
the associated allocdirect (on its ad_newdirblk list). When the
allocdirect has been satisfied, the newdirblk structure is moved
to the inodedep id_bufwait list of its directory to await the inode
being written. When the inode is written, the directory entries
are fully committed and can be deleted from their pagedep->id_pendinghd
and inodedep->id_pendinghd lists.
the number of references on the filesystem root vnode to be both
expected and released. Many filesystems hold an extra reference on
the filesystem root vnode, which must be accounted for when
determining if the filesystem is busy and then released if it isn't
busy. The old `skipvp' approach required individual filesystem
xxx_unmount functions to re-implement much of vflush()'s logic to
deal with the root vnode.
All 9 filesystems that hold an extra reference on the root vnode
got the logic wrong in the case of forced unmounts, so `umount -f'
would always fail if there were any extra root vnode references.
Fix this issue centrally in vflush(), now that we can.
This commit also fixes a vnode reference leak in devfs, which could
result in idle devfs filesystems that refuse to unmount.
Reviewed by: phk, bp
that are committed to being freed and reflect these blocks in the
counts returned by statfs (and thus also by the `df' command). This
change allows programs such as those that do news expiration to
know when to stop if they are trying to create a certain percentage
of free space. Note that this change does not solve the much harder
problem of making this to-be-freed space available to applications
that want it (thus on a nearly full filesystem, you may still
encounter out-of-space conditions even though the free space will
show up eventually). Hopefully this harder problem will be the
subject of a future enhancement.
1) Do not assume that the superblock will be of size fs->fs_bsize.
This fixes a panic when taking a snapshot on a filesystem with
a block size bigger than 8K.
2) Properly calculate the number of fragments that follow the
superblock summary information. This fixes a bug with inconsistent
snapshots.
3) When cleaning up a snapshot that is about to be removed, properly
calculate the number of blocks that need to be checked. This fixes
a bug that created partially allocated inodes.
4) When moving blocks from a snapshot that is about to be removed
to another snapshot, properly account for the reduced number of
blocks in the snapshot from which they are taken. This fixes a
bug in which the number of blocks released from a snapshot did not
match the number that it claimed to have.
by the inactive routine. Because the freeing causes the filesystem
to be modified, the close must be held up during periods when the
filesystem is suspended.
For snapshots to be consistent across crashes, they must write
blocks that they copy and claim those written blocks in their
on-disk block pointers before the old blocks that they referenced
can be allowed to be written.
Close a loophole that allowed unwritten blocks to be skipped when
doing ffs_sync with a request to wait for all I/O activity to be
completed.
to struct mount.
This makes the "struct netexport *" paramter to the vfs_export
and vfs_checkexport interface unneeded.
Consequently that all non-stacking filesystems can use
vfs_stdcheckexp().
At the same time, make it a pointer to a struct netexport
in struct mount, so that we can remove the bogus AF_MAX
and #include <net/radix.h> from <sys/mount.h>
fs_contigdirs, fs_avgfilesize and fs_avgfpdir. This could cause
panics if these fields were zeroed while a filesystem was mounted
read-only, and then remounted read-write.
Add code to ffs_reload() which copies the fs_contigdirs pointer
from the previous superblock, and reinitialises fs_avgf* if necessary.
Reviewed by: mckusick
sized blocks. To enable this option, use: `sysctl -w debug.bigcgs=1'.
Add debugging option to disable background writes of cylinder
groups. To enable this option, use: `sysctl -w debug.dobkgrdwrite=0'.
These debugging options should be tried on systems that are panicing
with corrupted cylinder group maps to see if it makes the problem
go away. The set of panics in question are:
ffs_clusteralloc: map mismatch
ffs_nodealloccg: map corrupted
ffs_nodealloccg: block not in map
ffs_alloccg: map corrupted
ffs_alloccg: block not in map
ffs_alloccgblk: cyl groups corrupted
ffs_alloccgblk: can't find blk in cyl
ffs_checkblk: partially free fragment
The following panics are less likely to be related to this problem,
but might be helped by these debugging options:
ffs_valloc: dup alloc
ffs_blkfree: freeing free block
ffs_blkfree: freeing free frag
ffs_vfree: freeing free inode
If you try these options, please report whether they helped reduce your
bitmap corruption panics to Kirk McKusick at <mckusick@mckusick.com>
and to Matt Dillon <dillon@earth.backplane.com>.
It is described in ufs/ffs/fs.h as follows:
/*
* Filesystem flags.
*
* Note that the FS_NEEDSFSCK flag is set and cleared only by the
* fsck utility. It is set when background fsck finds an unexpected
* inconsistency which requires a traditional foreground fsck to be
* run. Such inconsistencies should only be found after an uncorrectable
* disk error. A foreground fsck will clear the FS_NEEDSFSCK flag when
* it has successfully cleaned up the filesystem. The kernel uses this
* flag to enforce that inconsistent filesystems be mounted read-only.
*/
#define FS_UNCLEAN 0x01 /* filesystem not clean at mount */
#define FS_DOSOFTDEP 0x02 /* filesystem using soft dependencies */
#define FS_NEEDSFSCK 0x04 /* filesystem needs sync fsck before mount */
His description of the problem and solution follow. My own tests show
speedups on typical filesystem intensive workloads of 5% to 12% which
is very impressive considering the small amount of code change involved.
------
One day I noticed that some file operations run much faster on
small file systems then on big ones. I've looked at the ffs
algorithms, thought about them, and redesigned the dirpref algorithm.
First I want to describe the results of my tests. These results are old
and I have improved the algorithm after these tests were done. Nevertheless
they show how big the perfomance speedup may be. I have done two file/directory
intensive tests on a two OpenBSD systems with old and new dirpref algorithm.
The first test is "tar -xzf ports.tar.gz", the second is "rm -rf ports".
The ports.tar.gz file is the ports collection from the OpenBSD 2.8 release.
It contains 6596 directories and 13868 files. The test systems are:
1. Celeron-450, 128Mb, two IDE drives, the system at wd0, file system for
test is at wd1. Size of test file system is 8 Gb, number of cg=991,
size of cg is 8m, block size = 8k, fragment size = 1k OpenBSD-current
from Dec 2000 with BUFCACHEPERCENT=35
2. PIII-600, 128Mb, two IBM DTLA-307045 IDE drives at i815e, the system
at wd0, file system for test is at wd1. Size of test file system is 40 Gb,
number of cg=5324, size of cg is 8m, block size = 8k, fragment size = 1k
OpenBSD-current from Dec 2000 with BUFCACHEPERCENT=50
You can get more info about the test systems and methods at:
http://www.ptci.ru/gluk/dirpref/old/dirpref.html
Test Results
tar -xzf ports.tar.gz rm -rf ports
mode old dirpref new dirpref speedup old dirprefnew dirpref speedup
First system
normal 667 472 1.41 477 331 1.44
async 285 144 1.98 130 14 9.29
sync 768 616 1.25 477 334 1.43
softdep 413 252 1.64 241 38 6.34
Second system
normal 329 81 4.06 263.5 93.5 2.81
async 302 25.7 11.75 112 2.26 49.56
sync 281 57.0 4.93 263 90.5 2.9
softdep 341 40.6 8.4 284 4.76 59.66
"old dirpref" and "new dirpref" columns give a test time in seconds.
speedup - speed increasement in times, ie. old dirpref / new dirpref.
------
Algorithm description
The old dirpref algorithm is described in comments:
/*
* Find a cylinder to place a directory.
*
* The policy implemented by this algorithm is to select from
* among those cylinder groups with above the average number of
* free inodes, the one with the smallest number of directories.
*/
A new directory is allocated in a different cylinder groups than its
parent directory resulting in a directory tree that is spreaded across
all the cylinder groups. This spreading out results in a non-optimal
access to the directories and files. When we have a small filesystem
it is not a problem but when the filesystem is big then perfomance
degradation becomes very apparent.
What I mean by a big file system ?
1. A big filesystem is a filesystem which occupy 20-30 or more percent
of total drive space, i.e. first and last cylinder are physically
located relatively far from each other.
2. It has a relatively large number of cylinder groups, for example
more cylinder groups than 50% of the buffers in the buffer cache.
The first results in long access times, while the second results in
many buffers being used by metadata operations. Such operations use
cylinder group blocks and on-disk inode blocks. The cylinder group
block (fs->fs_cblkno) contains struct cg, inode and block bit maps.
It is 2k in size for the default filesystem parameters. If new and
parent directories are located in different cylinder groups then the
system performs more input/output operations and uses more buffers.
On filesystems with many cylinder groups, lots of cache buffers are
used for metadata operations.
My solution for this problem is very simple. I allocate many directories
in one cylinder group. I also do some things, so that the new allocation
method does not cause excessive fragmentation and all directory inodes
will not be located at a location far from its file's inodes and data.
The algorithm is:
/*
* Find a cylinder group to place a directory.
*
* The policy implemented by this algorithm is to allocate a
* directory inode in the same cylinder group as its parent
* directory, but also to reserve space for its files inodes
* and data. Restrict the number of directories which may be
* allocated one after another in the same cylinder group
* without intervening allocation of files.
*
* If we allocate a first level directory then force allocation
* in another cylinder group.
*/
My early versions of dirpref give me a good results for a wide range of
file operations and different filesystem capacities except one case:
those applications that create their entire directory structure first
and only later fill this structure with files.
My solution for such and similar cases is to limit a number of
directories which may be created one after another in the same cylinder
group without intervening file creations. For this purpose, I allocate
an array of counters at mount time. This array is linked to the superblock
fs->fs_contigdirs[cg]. Each time a directory is created the counter
increases and each time a file is created the counter decreases. A 60Gb
filesystem with 8mb/cg requires 10kb of memory for the counters array.
The maxcontigdirs is a maximum number of directories which may be created
without an intervening file creation. I found in my tests that the best
performance occurs when I restrict the number of directories in one cylinder
group such that all its files may be located in the same cylinder group.
There may be some deterioration in performance if all the file inodes
are in the same cylinder group as its containing directory, but their
data partially resides in a different cylinder group. The maxcontigdirs
value is calculated to try to prevent this condition. Since there is
no way to know how many files and directories will be allocated later
I added two optimization parameters in superblock/tunefs. They are:
int32_t fs_avgfilesize; /* expected average file size */
int32_t fs_avgfpdir; /* expected # of files per directory */
These parameters have reasonable defaults but may be tweeked for special
uses of a filesystem. They are only necessary in rare cases like better
tuning a filesystem being used to store a squid cache.
I have been using this algorithm for about 3 months. I have done
a lot of testing on filesystems with different capacities, average
filesize, average number of files per directory, and so on. I think
this algorithm has no negative impact on filesystem perfomance. It
works better than the default one in all cases. The new dirpref
will greatly improve untarring/removing/coping of big directories,
decrease load on cvs servers and much more. The new dirpref doesn't
speedup a compilation process, but also doesn't slow it down.
Obtained from: Grigoriy Orlov <gluk@ptci.ru>
(as is done in unmount).
Remove a snapshot inode from the superblock list when its last
name goes away rather than when its last reference goes away.
That way it will be properly reclaimed by fsck after a crash
rather than reenabled when the filesystem is mounted.
options UFS_EXTATTR and UFS_EXTATTR_AUTOSTART respectively. This change
reflects the fact that our EA support is implemented entirely at the
UFS layer (modulo FFS start/stop/autostart hooks for mount and unmount
events). This also better reflects the fact that [shortly] MFS will also
support EAs, as well as possibly IFS.
o Consumers of the EA support in FFS are reminded that as a result, they
must change kernel config files to reflect the new option names.
Obtained from: TrustedBSD Project
"options FFS_EXTATTR". When extended attribute auto-starting
is enabled, FFS will scan the .attribute directory off of the
root of each file system, as it is mounted. If .attribute
exists, EA support will be started for the file system. If
there are files in the directory, FFS will attempt to start
them as attribute backing files for attributes baring the same
name. All attributes are started before access to the file
system is permitted, so this permits race-free enabling of
attributes. For attributes backing support for security
features, such as ACLs, MAC, Capabilities, this is vital, as
it prevents the file system attributes from getting out of
sync as a result of file system operations between mount-time
and the enabling of the extended attribute. The userland
extattrctl tool will still function exactly as previously.
Files must be placed directly in .attribute, which must be
directly off of the file system root: symbolic links are
not permitted. FFS_EXTATTR will continue to be able
to function without FFS_EXTATTR_AUTOSTART for sites that do not
want/require auto-starting. If you're using the UFS_ACL code
available from www.TrustedBSD.org, using FFS_EXTATTR_AUTOSTART
is recommended.
o This support is implemented by adding an invocation of
ufs_extattr_autostart() to ffs_mountfs(). In addition,
several new supporting calls are introduced in
ufs_extattr.c:
ufs_extattr_autostart(): start EAs on the specified mount
ufs_extattr_lookup(): given a directory and filename,
return the vnode for the file.
ufs_extattr_enable_with_open(): invoke ufs_extattr_enable()
after doing the equililent of vn_open()
on the passed file.
ufs_extattr_iterate_directory(): iterate over a directory,
invoking ufs_extattr_lookup() and
ufs_extattr_enable_with_open() on each
entry.
o This feature is not widely tested, and therefore may contain
bugs, caution is advised. Several changes are in the pipeline
for this feature, including breaking out of EA namespaces into
subdirectories of .attribute (this is waiting on the updated
EA API), as well as a per-filesystem flag indicating whether
or not EAs should be auto-started. This is required because
administrators may not want .attribute auto-started on all
file systems, especially if non-administrators have write access
to the root of a file system.
Obtained from: TrustedBSD Project
structure rather than assuming that the device vnode would reside
in the FFS filesystem (which is obviously a broken assumption with
the device filesystem).
An initial tidyup of the mount() syscall and VFS mount code.
This code replaces the earlier work done by jlemon in an attempt to
make linux_mount() work.
* the guts of the mount work has been moved into vfs_mount().
* move `type', `path' and `flags' from being userland variables into being
kernel variables in vfs_mount(). `data' remains a pointer into
userspace.
* Attempt to verify the `type' and `path' strings passed to vfs_mount()
aren't too long.
* rework mount() and linux_mount() to take the userland parameters
(besides data, as mentioned) and pass kernel variables to vfs_mount().
(linux_mount() already did this, I've just tidied it up a little more.)
* remove the copyin*() stuff for `path'. `data' still requires copyin*()
since its a pointer into userland.
* set `mount->mnt_statf_mntonname' in vfs_mount() rather than in each
filesystem. This variable is generally initialised with `path', and
each filesystem can override it if they want to.
* NOTE: f_mntonname is intiailised with "/" in the case of a root mount.
that was introduced in revision 1.80. The problem manifested
itself with a `locking against myself' panic and could also
result in soft updates inconsistences associated with inodedeps.
The two problems are:
1) One of the background operations could manipulate the bitmap
while holding it locked with intent to create. This held lock
results in a `locking against myself' panic, when the background
processing that we have been coopted to do tries to lock the bitmap
which we are already holding locked. To understand how to fix this
problem, first, observe that we can do the background cleanups in
inodedep_lookup only when allocating inodedeps (DEPALLOC is set in
the call to inodedep_lookup). Second observe that calls to
inodedep_lookup with DEPALLOC set can only happen from the following
calls into the softdep code:
softdep_setup_inomapdep
softdep_setup_allocdirect
softdep_setup_remove
softdep_setup_freeblocks
softdep_setup_directory_change
softdep_setup_directory_add
softdep_change_linkcnt
Only the first two of these can come from ffs_alloc.c while holding
a bitmap locked. Thus, inodedep_lookup must not go off to do
request_cleanups when being called from these functions. This change
adds a flag, NODELAY, that can be passed to inodedep_lookup to let
it know that it should not do background processing in those cases.
2) The return value from request_cleanup when helping out with the
cleanup was 0 instead of 1. This meant that despite the fact that
we may have slept while doing the cleanups, the code did not recheck
for the appearance of an inodedep (e.g., goto top in inodedep_lookup).
This lead to the softdep inconsistency in which we ended up with
two inodedep's for the same inode.
Reviewed by: Peter Wemm <peter@yahoo-inc.com>,
Matt Dillon <dillon@earth.backplane.com>
- All processes go into the same array of queues, with different
scheduling classes using different portions of the array. This
allows user processes to have their priorities propogated up into
interrupt thread range if need be.
- I chose 64 run queues as an arbitrary number that is greater than
32. We used to have 4 separate arrays of 32 queues each, so this
may not be optimal. The new run queue code was written with this
in mind; changing the number of run queues only requires changing
constants in runq.h and adjusting the priority levels.
- The new run queue code takes the run queue as a parameter. This
is intended to be used to create per-cpu run queues. Implement
wrappers for compatibility with the old interface which pass in
the global run queue structure.
- Group the priority level, user priority, native priority (before
propogation) and the scheduling class into a struct priority.
- Change any hard coded priority levels that I found to use
symbolic constants (TTIPRI and TTOPRI).
- Remove the curpriority global variable and use that of curproc.
This was used to detect when a process' priority had lowered and
it should yield. We now effectively yield on every interrupt.
- Activate propogate_priority(). It should now have the desired
effect without needing to also propogate the scheduling class.
- Temporarily comment out the call to vm_page_zero_idle() in the
idle loop. It interfered with propogate_priority() because
the idle process needed to do a non-blocking acquire of Giant
and then other processes would try to propogate their priority
onto it. The idle process should not do anything except idle.
vm_page_zero_idle() will return in the form of an idle priority
kernel thread which is woken up at apprioriate times by the vm
system.
- Update struct kinfo_proc to the new priority interface. Deliberately
change its size by adjusting the spare fields. It remained the same
size, but the layout has changed, so userland processes that use it
would parse the data incorrectly. The size constraint should really
be changed to an arbitrary version number. Also add a debug.sizeof
sysctl node for struct kinfo_proc.
mtx_enter(lock, type) becomes:
mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)
similarily, for releasing a lock, we now have:
mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.
The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.
Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:
MTX_QUIET and MTX_NOSWITCH
The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:
mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.
Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.
Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.
Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.
Finally, caught up to the interface changes in all sys code.
Contributors: jake, jhb, jasone (in no particular order)
filesystem softdep_process_worklist() is called in a loop until it indicates
that no dependancies remain, but the determination of that fact depends on
there only being one softdep_process_worklist() instance running. It was
possible for the syncer to also be running softdep_process_worklist()
and the pre-existing checks in the code to prevent this were not sufficient
to prevent the race. This patch solves the problem.
Approved-by: mckusick
in-core pointers to summary information. An array in this region
(fs_csp) could overflow on filesystems with a very large number of
cylinder groups (~16000 on i386 with 8k blocks). When this happens,
other fields in the superblock get corrupted, and fsck refuses to
check the filesystem.
Solve this problem by replacing the fs_csp array in 'struct fs'
with a single pointer, and add padding to keep the length of the
128-byte region fixed. Update the kernel and userland utilities
to use just this single pointer.
With this change, the kernel no longer makes use of the superblock
fields 'fs_csshift' and 'fs_csmask'. Add a comment to newfs/mkfs.c
to indicate that these fields must be calculated for compatibility
with older kernels.
Reviewed by: mckusick
1) Be more tolerant of missing snapshot files by only trying to decrement
their reference count if they are registered as active.
2) Fix for snapshots of filesystems with block sizes larger than 8K
(from Ollivier Robert <roberto@eurocontrol.fr>).
3) Fix to avoid losing last block in snapshot file when calculating blocks
that need to be copied (from Don Coleman <coleman@coleman.org>).
which fails to set the modification time on the file. The same
check a few lines later takes the correct action.
Submitted by: Ian Dowse <iedowse@maths.tcd.ie>
Previously, the syncer process was the only process in the
system that could process the soft updates background work
list. If enough other processes were adding requests to that
list, it would eventually grow without bound. Because some of
the work list requests require vnodes to be locked, it was
not generally safe to let random processes process the work
list while they already held vnodes locked. By adding a flag
to the work list queue processing function to indicate whether
the calling process could safely lock vnodes, it becomes possible
to co-opt other processes into helping out with the work list.
Now when the worklist gets too large, other processes can safely
help out by picking off those work requests that can be handled
without locking a vnode, leaving only the small number of
requests requiring a vnode lock for the syncer process. With
this change, it appears possible to keep even the nastiest
workloads under control.
Submitted by: Paul Saab <ps@yahoo-inc.com>
in the face of multiple processes doing massive numbers of filesystem
operations. While this patch will work in nearly all situations, there
are still some perverse workloads that can overwhelm the system.
Detecting and handling these perverse workloads will be the subject
of another patch.
Reviewed by: Paul Saab <ps@yahoo-inc.com>
Obtained from: Ethan Solomita <ethan@geocast.com>
Removed most of the hacks that were trying to deal with low-memory
situations prior to now.
The new code is based on the concept that I/O must be able to function in
a low memory situation. All major modules related to I/O (except
networking) have been adjusted to allow allocation out of the system
reserve memory pool. These modules now detect a low memory situation but
rather then block they instead continue to operate, then return resources
to the memory pool instead of cache them or leave them wired.
Code has been added to stall in a low-memory situation prior to a vnode
being locked.
Thus situations where a process blocks in a low-memory condition while
holding a locked vnode have been reduced to near nothing. Not only will
I/O continue to operate, but many prior deadlock conditions simply no
longer exist.
Implement a number of VFS/BIO fixes
(found by Ian): in biodone(), bogus-page replacement code, the loop
was not properly incrementing loop variables prior to a continue
statement. We do not believe this code can be hit anyway but we
aren't taking any chances. We'll turn the whole section into a
panic (as it already is in brelse()) after the release is rolled.
In biodone(), the foff calculation was incorrectly
clamped to the iosize, causing the wrong foff to be calculated
for pages in the case of an I/O error or biodone() called without
initiating I/O. The problem always caused a panic before. Now it
doesn't. The problem is mainly an issue with NFS.
Fixed casts for ~PAGE_MASK. This code worked properly before only
because the calculations use signed arithmatic. Better to properly
extend PAGE_MASK first before inverting it for the 64 bit masking
op.
In brelse(), the bogus_page fixup code was improperly throwing
away the original contents of 'm' when it did the j-loop to
fix the bogus pages. The result was that it would potentially
invalidate parts of the *WRONG* page(!), leading to corruption.
There may still be cases where a background bitmap write is
being duplicated, causing potential corruption. We have identified
a potentially serious bug related to this but the fix is still TBD.
So instead this patch contains a KASSERT to detect the problem
and panic the machine rather then continue to corrupt the filesystem.
The problem does not occur very often.. it is very hard to
reproduce, and it may or may not be the cause of the corruption
people have reported.
Review by: (VFS/BIO: mckusick, Ian Dowse <iedowse@maths.tcd.ie>)
Testing by: (VM/Deadlock) Paul Saab <ps@yahoo-inc.com>
is to first write the deleted directory entry to disk, second write
the zero'ed inode to disk, and finally to release the freed blocks
and the inode back to the cylinder-group map. As this ordering
requires two disk writes to occur which are normally spaced about
30 seconds apart (except when memory is under duress), it takes
about a minute from the time that a file is deleted until its inode
and data blocks show up in the cylinder-group map for reallocation.
If a file has had only a brief lifetime (less than 30 seconds from
creation to deletion), neither its inode nor its directory entry
may have been written to disk. If its directory entry has not been
written to disk, then we need not wait for that directory block to
be written as the on-disk directory block does not reference the
inode. Similarly, if the allocated inode has never been written to
disk, we do not have to wait for it to be written back either as
its on-disk representation is still zero'ed out. Thus, in the case
of a short lived file, we can simply release the blocks and inode
to the cylinder-group map immediately. As the inode and its blocks
are released immediately, they are immediately available for other
uses. If they are not released for a minute, then other inodes and
blocks must be allocated for short lived files, cluttering up the
vnode and buffer caches. The previous code was a bit too aggressive
in trying to release the blocks and inode back to the cylinder-group
map resulting in their being made available when in fact the inode
on disk had not yet been zero'ed. This patch takes a more conservative
approach to doing the release which avoids doing the release prematurely.
description:
How it works:
--
Basically ifs is a copy of ffs, overriding some vfs/vnops. (Yes, hack.)
I didn't see the need in duplicating all of sys/ufs/ffs to get this
off the ground.
File creation is done through a special file - 'newfile' . When newfile
is called, the system allocates and returns an inode. Note that newfile
is done in a cloning fashion:
fd = open("newfile", O_CREAT|O_RDWR, 0644);
fstat(fd, &st);
printf("new file is %d\n", (int)st.st_ino);
Once you have created a file, you can open() and unlink() it by its returned
inode number retrieved from the stat call, ie:
fd = open("5", O_RDWR);
The creation permissions depend entirely if you have write access to the
root directory of the filesystem.
To get the list of currently allocated inodes, VOP_READDIR has been added
which returns a directory listing of those currently allocated.
--
What this entails:
* patching conf/files and conf/options to include IFS as a new compile
option (and since ifs depends upon FFS, include the FFS routines)
* An entry in i386/conf/NOTES indicating IFS exists and where to go for
an explanation
* Unstaticize a couple of routines in src/sys/ufs/ffs/ which the IFS
routines require (ffs_mount() and ffs_reload())
* a new bunch of routines in src/sys/ufs/ifs/ which implement the IFS
routines. IFS replaces some of the vfsops, and a handful of vnops -
most notably are VFS_VGET(), VOP_LOOKUP(), VOP_UNLINK() and VOP_READDIR().
Any other directory operation is marked as invalid.
What this results in:
* an IFS partition's create permissions are controlled by the perm/ownership of
the root mount point, just like a normal directory
* Each inode has perm and ownership too
* IFS does *NOT* mean an FFS partition can be opened per inode. This is a
completely seperate filesystem here
* Softupdates doesn't work with IFS, and really I don't think it needs it.
Besides, fsck's are FAST. (Try it :-)
* Inodes 0 and 1 aren't allocatable because they are special (dump/swap IIRC).
Inode 2 isn't allocatable since UFS/FFS locks all inodes in the system against
this particular inode, and unravelling THAT code isn't trivial. Therefore,
useful inodes start at 3.
Enjoy, and feedback is definitely appreciated!
it is defined whenm used in ufs_extattr_uepm_destroy(), fixing a panic
due to a NULL pointer dereference.
Submitted by: Wesley Morgan <morganw@chemicals.tacorp.com>
up lock on extattrs.
o Get for free a comment indicating where auto-starting of extended
attributes will eventually occur, as it was in my commit tree also.
No implementation change here, only a comment.
Add lockdestroy() and appropriate invocations, which corresponds to
lockinit() and must be called to clean up after a lockmgr lock is no
longer needed.
separately (nfs, cd9660 etc) or keept as a first element of structure
referenced by v_data pointer(ffs). Such organization leads to known problems
with stacked filesystems.
From this point vop_no*lock*() functions maintain only interlock lock.
vop_std*lock*() functions maintain built-in v_lock structure using lockmgr().
vop_sharedlock() is compatible with vop_stdunlock(), but maintains a shared
lock on vnode.
If filesystem wishes to export lockmgr compatible lock, it can put an address
of this lock to v_vnlock field. This indicates that the upper filesystem
can take advantage of it and use single lock structure for entire (or part)
of stack of vnodes. This field shouldn't be examined or modified by VFS code
except for initialization purposes.
Reviewed in general by: mckusick
include:
* Mutual exclusion is used instead of spl*(). See mutex(9). (Note: The
alpha port is still in transition and currently uses both.)
* Per-CPU idle processes.
* Interrupts are run in their own separate kernel threads and can be
preempted (i386 only).
Partially contributed by: BSDi (BSD/OS)
Submissions by (at least): cp, dfr, dillon, grog, jake, jhb, sheldonh
This allows ffs_fsync() to break out of a loop that might otherwise
be infinite on kernels compiled without the SOFTUPDATES option.
The observed symptom was a system hang at the first unmount attempt.
the SF_IMMUTABLE flag to prevent writing. Instead put in explicit
checking for the SF_SNAPSHOT flag in the appropriate places. With
this change, it is now possible to rename and link to snapshot files.
It is also possible to set or clear any of the owner, group, or
other read bits on the file, though none of the write or execute
bits can be set. There is also an explicit test to prevent the
setting or clearing of the SF_SNAPSHOT flag via chflags() or
fchflags(). Note also that the modify time cannot be changed as
it needs to accurately reflect the time that the snapshot was taken.
Submitted by: Robert Watson <rwatson@FreeBSD.org>
with the new snapshot code.
Update addaliasu to correctly implement the semantics of the old
checkalias function. When a device vnode first comes into existence,
check to see if an anonymous vnode for the same device was created
at boot time by bdevvp(). If so, adopt the bdevvp vnode rather than
creating a new vnode for the device. This corrects a problem which
caused the kernel to panic when taking a snapshot of the root
filesystem.
Change the calling convention of vn_write_suspend_wait() to be the
same as vn_start_write().
Split out softdep_flushworklist() from softdep_flushfiles() so that
it can be used to clear the work queue when suspending filesystem
operations.
Access to buffers becomes recursive so that snapshots can recursively
traverse their indirect blocks using ffs_copyonwrite() when checking
for the need for copy on write when flushing one of their own indirect
blocks. This eliminates a deadlock between the syncer daemon and a
process taking a snapshot.
Ensure that softdep_process_worklist() can never block because of a
snapshot being taken. This eliminates a problem with buffer starvation.
Cleanup change in ffs_sync() which did not synchronously wait when
MNT_WAIT was specified. The result was an unclean filesystem panic
when doing forcible unmount with heavy filesystem I/O in progress.
Return a zero'ed block when reading a block that was not in use at
the time that a snapshot was taken. Normally, these blocks should
never be read. However, the readahead code will occationally read
them which can cause unexpected behavior.
Clean up the debugging code that ensures that no blocks be written
on a filesystem while it is suspended. Snapshots must explicitly
label the blocks that they are writing during the suspension so that
they do not cause a `write on suspended filesystem' panic.
Reorganize ffs_copyonwrite() to eliminate a deadlock and also to
prevent a race condition that would permit the same block to be
copied twice. This change eliminates an unexpected soft updates
inconsistency in fsck caused by the double allocation.
Use bqrelse rather than brelse for buffers that will be needed
soon again by the snapshot code. This improves snapshot performance.
the gating of system calls that cause modifications to the underlying
filesystem. The gating can be enabled by any filesystem that needs
to consistently suspend operations by adding the vop_stdgetwritemount
to their set of vnops. Once gating is enabled, the function
vfs_write_suspend stops all new write operations to a filesystem,
allows any filesystem modifying system calls already in progress
to complete, then sync's the filesystem to disk and returns. The
function vfs_write_resume allows the suspended write operations to
begin again. Gating is not added by default for all filesystems as
for SMP systems it adds two extra locks to such critical kernel
paths as the write system call. Thus, gating should only be added
as needed.
Details on the use and current status of snapshots in FFS can be
found in /sys/ufs/ffs/README.snapshot so for brevity and timelyness
is not included here. Unless and until you create a snapshot file,
these changes should have no effect on your system (famous last words).
in mount.h instead of ffs_extern.h. The correct solution is to use
an indirect function pointer so that the kernel does not have to be
built with options FFS, but that will be left for another day.
advance preparation for them to get migrated into place so that
subsequent changes in utilities will not fail to compile for lack
of up-to-date header files in /usr/include.
the system would panic when a user's inode quota was exceeded (see
PR 18959 for details). This fixes that problem.
PR: 18959
Submitted by: Jason Godsey <jason@unixguy.fidalgo.net>
check to see if it has been committed to disk. If it has never
been written, it can be freed immediately. For short lived files
this change allows the same inode to be reused repeatedly.
Similarly, when upgrading a fragment to a larger size, if it
has never been claimed by an inode on disk, it too can be freed
immediately making it available for reuse often in the next slowly
growing block of the same file.
if an FFS partition returns EOPNOTSUPP, as it just means extended
attributes weren't enabled on that partition. Prevents spurious
warning per-partition at shutdown.
<sys/bio.h>.
<sys/bio.h> is now a prerequisite for <sys/buf.h> but it shall
not be made a nested include according to bdes teachings on the
subject of nested includes.
Diskdrivers and similar stuff below specfs::strategy() should no
longer need to include <sys/buf.> unless they need caching of data.
Still a few bogus uses of struct buf to track down.
Repocopy by: peter
(name, value) pairs to be associated with inodes. This support is
used for ACLs, MAC labels, and Capabilities in the TrustedBSD
security extensions, which are currently under development.
In this implementation, attributes are backed to data vnodes in the
style of the quota support in FFS. Support for FFS extended
attributes may be enabled using the FFS_EXTATTR kernel option
(disabled by default). Userland utilities and man pages will be
committed in the next batch. VFS interfaces and man pages have
been in the repo since 4.0-RELEASE and are unchanged.
o ufs/ufs/extattr.h: UFS-specific extattr defines
o ufs/ufs/ufs_extattr.c: bulk of support routines
o ufs/{ufs,ffs,mfs}/*.[ch]: hooks and extattr.h includes
o contrib/softupdates/ffs_softdep.c: extattr.h includes
o conf/options, conf/files, i386/conf/LINT: added FFS_EXTATTR
o coda/coda_vfsops.c: XXX required extattr.h due to ufsmount.h
(This should not be the case, and will be fixed in a future commit)
Currently attributes are not supported in MFS. This will be fixed.
Reviewed by: adrian, bp, freebsd-fs, other unthanked souls
Obtained from: TrustedBSD Project
(Much of this done by script)
Move B_ORDERED flag to b_ioflags and call it BIO_ORDERED.
Move b_pblkno and b_iodone_chain to struct bio while we transition, they
will be obsoleted once bio structs chain/stack.
Add bio_queue field for struct bio aware disksort.
Address a lot of stylistic issues brought up by bde.
substitute BUF_WRITE(foo) for VOP_BWRITE(foo->b_vp, foo)
substitute BUF_STRATEGY(foo) for VOP_STRATEGY(foo->b_vp, foo)
This patch is machine generated except for the ccd.c and buf.h parts.
field in struct buf: b_iocmd. The b_iocmd is enforced to have
exactly one bit set.
B_WRITE was bogusly defined as zero giving rise to obvious coding
mistakes.
Also eliminate the redundant struct buf flag B_CALL, it can just
as efficiently be done by comparing b_iodone to NULL.
Should you get a panic or drop into the debugger, complaining about
"b_iocmd", don't continue. It is likely to write on your disk
where it should have been reading.
This change is a step in the direction towards a stackable BIO capability.
A lot of this patch were machine generated (Thanks to style(9) compliance!)
Vinum users: Greg has not had time to test this yet, be careful.
filesystem fills up. If the first indirect block exists and FFS is able
to allocate deeper indirect blocks, but is not able to allocate the
data block, FFS improperly unwinds the indirect blocks and leaves a
block pointer hanging to a freed block. This will cause a panic later
when the file is removed. The solution is to properly account for the
first block-pointer-to-an-indirect-block we had to create in a balloc
operation and then unwind it if a failure occurs.
Detective work by: Ian Dowse <iedowse@maths.tcd.ie>
Reviewed by: mckusick, Ian Dowse <iedowse@maths.tcd.ie>
Approved by: jkh
have a write in progress. Otherwise one can get in an infinite loop
trying to get them all flushed.
Submitted by: Matthew Dillon <dillon@apollo.backplane.com>
set of restrictions for cancelling an inode dependency (inodedep)
is somewhat stronger than originally coded. Since this check appears
in two places, we codify it into the function check_inode_unwritten
which we then call from the two sites, one freeing blocks and the
other freeing directory entries.
Submitted by: Steinar Haug via Matthew Dillon
so that they never try to lock an inode corresponding to ".." as this
can lead to deadlock. We observe that any inode with an updated link count
is always pushed into its buffer at the time of the link count change, so
we do not need to do a VOP_UPDATE, but merely find its buffer and write it.
The only time we need to get the inode itself is from the result of a
mkdir whose name will never be ".." and hence locking such an inode will
never request a lock above us in the filesystem tree. Thanks to Brian
Fundakowski Feldman for providing the test program that tickled soft updates
into hanging in "inode" sleep.
Submitted by: Brian Fundakowski Feldman <green@FreeBSD.org>
to sleep). Locking 101, part 2: do not look at buffer contents after
you have been asleep. There is no telling what wonderous changes may
have occurred.
This seems to be responsible for a bunch of panics where the process
sleeps and something else finds softupdates "locked" when it shouldn't
be. This commit is unreviewed, but has been a big help here.
Previously my boxes would panic pretty much on the first fsync() that
wrote something to disk.
it is no longer sufficient to get a lock on a buffer to know
that its write has been completed. We have to first get the
lock on the buffer, then check to see if it is doing a
background write. If it is doing background write, we have
to wait for the background write to finish, then check to see
if that fullfilled our dependency, and if not to start another
write. Luckily the explanation is longer than the fix.
a vnode has not been written (which would clear certain of its
dependencies). The problems arises because fsync with MNT_NOWAIT
no longer pushes all the dirty blocks associated with a vnode. It
skips those that require rollbacks, since they will just get instantly
dirty again. Such skipped blocks are marked so that they will not be
skipped a second time (otherwise circular dependencies would never
clear). So, we fsync twice to ensure that everything will be written
at least once.
The problem occurs when an indirect block and a data block are
being allocated at the same time. For example when the 13th block
of the file is written, the filesystem needs to allocate the first
indirect block and a data block. If the indirect block allocation
succeeds, but the data block allocation fails, the error code
dellocates the indirect block as it has nothing at which to point.
Unfortunately, it does not deallocate the indirect block's associated
dependencies which then fail when they find the block unexpectedly
gone (ptr == 0 instead of its expected value). The fix is to fsync
the file before doing the block rollback, as the fsync will flush
out all of the dependencies. Once the rollback is done the file
must be fsync'ed again so that the soft updates code does not find
unexpected changes. This approach is much slower than writing the
code to back out the extraneous dependencies, but running out of
disk space is not expected to be a common occurence, so just getting
it right is the main criterion.
PR: kern/15063
Submitted by: Assar Westerlund <assar@stacken.kth.se>
have been cleaned up by deallocte_dependencies(). Once that is done, it
is safe to post the request to free the blocks. A similar change is also
needed for the freefile case.
1) Fastpath deletions. When a file is being deleted, check to see if it
was so recently created that its inode has not yet been written to
disk. If so, the delete can proceed to immediately free the inode.
2) Background writes: No file or block allocations can be done while the
bitmap is being written to disk. To avoid these stalls, the bitmap is
copied to another buffer which is written thus leaving the original
available for futher allocations.
3) Link count tracking. Constantly track the difference in i_effnlink and
i_nlink so that inodes that have had no change other than i_effnlink
need not be written.
4) Identify buffers with rollback dependencies so that the buffer flushing
daemon can choose to skip over them.
of dirrem structure rather than the collaterally created freeblks
and freefile structures. Limit the rate of buffer dirtying by the
syncer process during periods of intense file removal.
check before the inode is unlocked while grabbing its parent directory.
Once it is unlocked, other operations may slip in that could make
the inode-is-flushed check fail. Allowing other writes to the inode
before returning from fsync does not break the semantics of fsync
since we have flushed everything that was dirty at the time of the
fsync call.
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.
when I made the absence of the clean flag sticky in rev.1.88. This
was a problem main for "mount /". There is no way to mount "/" for
writing without using mount -u (normally implicitly), so after
"mount -f /" of an unclean filesystem, the absence of the clean flag
was sticky forever.
quite dangerous, since the process may hold locks at the point,
and if it is stopped in that tsleep the machine may hang. Because
the sleep is so short, the PCATCH is not required here, so it has
been removed. For the future, the FreeBSD team needs to decide
whether it is still reasonable to stop a process in tsleep, as that
may affect any other code that uses PCATCH while holding kernel locks.
Submitted by: Dmitrij Tejblum <tejblum@arc.hq.cti.ru>
Reviewed by: Kirk McKusick <mckusick@mckusick.com>
* lockstatus() and VOP_ISLOCKED() gets a new process argument and a new
return value: LK_EXCLOTHER, when the lock is held exclusively by another
process.
* The ASSERT_VOP_(UN)LOCKED family is extended to use what this gives them
* Extend the vnode_if.src format to allow more exact specification than
locked/unlocked.
This commit should not do any semantic changes unless you are using
DEBUG_VFS_LOCKS.
Discussed with: grog, mch, peter, phk
Reviewed by: peter
Correctly lock vnodes when calling VOP_OPEN() from filesystem mount code.
Unify spec_open() for bdev and cdev cases.
Remove the disabled bdev specific read/write code.
the soft updates changes: only report the link count to be i_effnlink
in ufs_getattr() for file systems that maintain i_effnlink.
Tested by: Mike Dracopoulos <mdraco@math.uoa.gr>
Merge the contents (less some trivial bordering the silly comments)
of <vm/vm_prot.h> and <vm/vm_inherit.h> into <vm/vm.h>. This puts
the #defines for the vm_inherit_t and vm_prot_t types next to their
typedefs.
This paves the road for the commit to follow shortly: change
useracc() to use VM_PROT_{READ|WRITE} rather than B_{READ|WRITE}
as argument.
been set for a mount point. Insert missing checks to ensure that all
write operations are done asynchronously when the MNT_ASYNC option
has been requested.
Submitted by: Craig A Soules <soules+@andrew.cmu.edu>
Reviewed by: Kirk McKusick <mckusick@mckusick.com>
lockmgr locks. This commit should be functionally equivalent to the old
semantics. That is, all buffer locking is done with LK_EXCLUSIVE
requests. Changes to take advantage of LK_SHARED and LK_RECURSIVE will
be done in future commits.
The cdevsw_add() function now finds the major number(s) in the
struct cdevsw passed to it. cdevsw_add_generic() is no longer
needed, cdevsw_add() does the same thing.
cdevsw_add() will print an message if the d_maj field looks bogus.
Remove nblkdev and nchrdev variables. Most places they were used
bogusly. Instead check a dev_t for validity by seeing if devsw()
or bdevsw() returns NULL.
Move bdevsw() and devsw() functions to kern/kern_conf.c
Bump __FreeBSD_version to 400006
This commit removes:
72 bogus makedev() calls
26 bogus SYSINIT functions
if_xe.c bogusly accessed cdevsw[], author/maintainer please fix.
I4b and vinum not changed. Patches emailed to authors. LINT
probably broken until they catch up.
a sync on the block device for the filesystem. That allows it to push the
bitmap blocks before the inode blocks which greatly reduces the number of
inode rollbacks that need to be done.
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>
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>
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>
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.
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.
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>
- 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)
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)
