Commit Graph

968 Commits

Author SHA1 Message Date
Robert Watson
885868cd8f Remove VOP_LEASE and supporting functions. This hasn't been used since
the removal of NQNFS, but was left in in case it was required for NFSv4.
Since our new NFSv4 client and server can't use it for their
requirements, GC the old mechanism, as well as other unused lease-
related code and interfaces.

Due to its impact on kernel programming and binary interfaces, this
change should not be MFC'd.

Proposed by:    jeff
Reviewed by:    jeff
Discussed with: rmacklem, zach loafman @ isilon
2009-04-10 10:52:19 +00:00
Konstantin Belousov
bc364c4e99 When removing or renaming snaphost, do not delve into request_cleanup().
The later may need blocks from the underlying device that belongs
to normal files, that should not be locked while snap lock is held.

Reported and tested by:	pho
MFC after:	1 month
2009-04-04 12:19:52 +00:00
Konstantin Belousov
02e06d99e6 Correct typo.
Noted by:	kensmith
2009-03-27 15:46:02 +00:00
Konstantin Belousov
c1d8b5e82c Fix two issues with bufdaemon, often causing the processes to hang in
the "nbufkv" sleep.

First, ffs background cg group block write requests a new buffer for
the shadow copy. When ffs_bufwrite() is called from the bufdaemon due
to buffers shortage, requesting the buffer deadlock bufdaemon.
Introduce a new flag for getnewbuf(), GB_NOWAIT_BD, to request getblk
to not block while allocating the buffer, and return failure
instead. Add a flag argument to the geteblk to allow to pass the flags
to getblk(). Do not repeat the getnewbuf() call from geteblk if buffer
allocation failed and either GB_NOWAIT_BD is specified, or geteblk()
is called from bufdaemon (or its helper, see below). In
ffs_bufwrite(), fall back to synchronous cg block write if shadow
block allocation failed.

Since r107847, buffer write assumes that vnode owning the buffer is
locked. The second problem is that buffer cache may accumulate many
buffers belonging to limited number of vnodes. With such workload,
quite often threads that own the mentioned vnodes locks are trying to
read another block from the vnodes, and, due to buffer cache
exhaustion, are asking bufdaemon for help. Bufdaemon is unable to make
any substantial progress because the vnodes are locked.

Allow the threads owning vnode locks to help the bufdaemon by doing
the flush pass over the buffer cache before getnewbuf() is going to
uninterruptible sleep. Move the flushing code from buf_daemon() to new
helper function buf_do_flush(), that is called from getnewbuf().  The
number of buffers flushed by single call to buf_do_flush() from
getnewbuf() is limited by new sysctl vfs.flushbufqtarget.  Prevent
recursive calls to buf_do_flush() by marking the bufdaemon and threads
that temporarily help bufdaemon by TDP_BUFNEED flag.

In collaboration with:	pho
Reviewed by:	 tegge (previous version)
Tested by:	 glebius, yandex ...
MFC after:	 3 weeks
2009-03-16 15:39:46 +00:00
Konstantin Belousov
e65f5a4ead The non-modifying EA VOPs are executed with only shared vnode lock taken.
Provide a custom lock around initializing and tearing down EA area,
to prevent both memory leaks and double-free of it. Count the number
of EA area accessors.

Lock protocol requires either holding exclusive vnode lock to modify
i_ea_area, or shared vnode lock and owning IN_EA_LOCKED flag in i_flag.

Noted by:	YAMAMOTO, Taku <taku tackymt homeip net>
Tested by:	pho (previous version)
MFC after:	2 weeks
2009-03-12 12:43:56 +00:00
Konstantin Belousov
a9d9537110 Do not double-free the struct inode when insmntque failed. Default
insmntque destructor reclaims the vnode, and ufs_reclaim frees the memory.

Reviewed by:	tegge
MFC after:	3 days
2009-03-11 19:45:52 +00:00
John Baldwin
33fc362512 Add a new internal mount flag (MNTK_EXTENDED_SHARED) to indicate that a
filesystem supports additional operations using shared vnode locks.
Currently this is used to enable shared locks for open() and close() of
read-only file descriptors.
- When an ISOPEN namei() request is performed with LOCKSHARED, use a
  shared vnode lock for the leaf vnode only if the mount point has the
  extended shared flag set.
- Set LOCKSHARED in vn_open_cred() for requests that specify O_RDONLY but
  not O_CREAT.
- Use a shared vnode lock around VOP_CLOSE() if the file was opened with
  O_RDONLY and the mountpoint has the extended shared flag set.
- Adjust md(4) to upgrade the vnode lock on the vnode it gets back from
  vn_open() since it now may only have a shared vnode lock.
- Don't enable shared vnode locks on FIFO vnodes in ZFS and UFS since
  FIFO's require exclusive vnode locks for their open() and close()
  routines.  (My recent MPSAFE patches for UDF and cd9660 already included
  this change.)
- Enable extended shared operations on UFS, cd9660, and UDF.

Submitted by:	ups
Reviewed by:	pjd (ZFS bits)
MFC after:	1 month
2009-03-11 14:13:47 +00:00
John Baldwin
5bd65606f4 Adjust some variables (mostly related to the buffer cache) that hold
address space sizes to be longs instead of ints.  Specifically, the follow
values are now longs: runningbufspace, bufspace, maxbufspace,
bufmallocspace, maxbufmallocspace, lobufspace, hibufspace, lorunningspace,
hirunningspace, maxswzone, maxbcache, and maxpipekva.  Previously, a
relatively small number (~ 44000) of buffers set in kern.nbuf would result
in integer overflows resulting either in hangs or bogus values of
hidirtybuffers and lodirtybuffers.  Now one has to overflow a long to see
such problems.  There was a check for a nbuf setting that would cause
overflows in the auto-tuning of nbuf.  I've changed it to always check and
cap nbuf but warn if a user-supplied tunable would cause overflow.

Note that this changes the ABI of several sysctls that are used by things
like top(1), etc., so any MFC would probably require a some gross shims
to allow for that.

MFC after:	1 month
2009-03-09 19:35:20 +00:00
Edward Tomasz Napierala
4f560d7595 Right now, when trying to unmount a device that's already gone,
msdosfs_unmount() and ffs_unmount() exit early after getting ENXIO.
However, dounmount() treats ENXIO as a success and proceeds with
unmounting.  In effect, the filesystem gets unmounted without closing
GEOM provider etc.

Reviewed by:	kib
Approved by:	rwatson (mentor)
Tested by:	dho
Sponsored by:	FreeBSD Foundation
2009-02-23 21:09:28 +00:00
Edward Tomasz Napierala
3c140b2df4 Refactor, moving error checking outside of the
'if (mp->mnt_flag & MNT_SOFTDEP)' conditional.  No functional
changes.

Reviewed by:	kib
Approved by:	rwatson (mentor)
Tested by:	pho
Sponsored by:	FreeBSD Foundation
2009-02-23 20:56:27 +00:00
John Baldwin
ee445a69c5 - If the g_access() call for the initial root mount fails, then fully
cleanup.  Before the GEOM consumer would not have been closed.
- Bump the reference on the character device being mounted while the
  associated devfs vnode is locked.

Reviewed by:	kib
2009-02-11 22:19:54 +00:00
Edward Tomasz Napierala
8a3f2c376a When a device containing mounted UFS filesystem disappears, the type
of devvp becomes VBAD, which UFS incorrectly interprets as snapshot
vnode, which in turns causes panic.  Fix it by replacing '!= VCHR'
with '== VREG'.

With this fix in place, you should no longer be able to panic the system
by removing a device with an UFS filesystem mounted from it - assuming
you don't use softupdates.

Reviewed by:	kib
Tested by:	pho
Approved by:	rwatson (mentor)
Sponsored by:	FreeBSD Foundation
2009-02-06 17:14:07 +00:00
Edward Tomasz Napierala
49c4791ccc Make sure the cdev doesn't go away while the filesystem is still mounted.
Otherwise dev2udev() could return garbage.

Reviewed by:	kib
Approved by:	rwatson (mentor)
Sponsored by:	FreeBSD Foundation
2009-01-29 16:47:15 +00:00
Robert Watson
ec7e66e84c Following a fair amount of real world experience with ACLs and
extended attributes since FreeBSD 5, make the following semantic
changes:

- Don't update the inode modification time (mtime) when extended
  attributes (and hence also ACLs) are added, modified, or removed.
- Don't update the inode access tie (atime) when extended attributes
  (and hence also ACLs) are queried.

This means that rsync (and related tools) won't improperly think
that the data in the file has changed when only the ACL has changed.

Note that ffs_reallocblks() has not been changed to not update on an
IO_EXT transaction, but currently EAs don't use the cluster write
routines so this shouldn't be a problem.  If EAs grow support for
clustering, then VOP_REALLOCBLKS() will need to grow a flag argument
to carry down IO_EXT to UFS.

MFC after:	1 week
PR:             ports/125739
Reported by:    Alexander Zagrebin <alexz@visp.ru>
Tested by:      pluknet <pluknet@gmail.com>,
                Greg Byshenk <freebsd@byshenk.net>
Discussed with: kib, kientzle, timur, Alexander Bokovoy <ab@samba.org>
2009-01-27 21:48:47 +00:00
Konstantin Belousov
b51b07be87 The r187467 should remove all pages for V_NORMAL case too, because
indirect block pages are not removed by the mentioned invocation of
the vnode_pager_setsize().

Put a common code into the helper function ffs_pages_remove().

Reported and tested by:	dchagin
Reviewed by:	ups
MFC after:	3 weeks
2009-01-20 22:00:19 +00:00
Konstantin Belousov
b1a4c8e522 When extending inode size, we call vnode_pager_setsize(), to have a
address space where to put vnode pages, and then call UFS_BALLOC(),
to actually allocate new block and map it. When UFS_BALLOC() returns
error, sometimes we forget to revert the vm object size increase,
allowing for the pages that are not backed by the logical disk blocks.

Revert vnode_pager_setsize() back when UFS_BALLOC() failed, for
ffs_truncate() and ffs_write().

PR:	129956
Reviewed by:	ups
MFC after:	3 weeks
2009-01-20 11:30:22 +00:00
Konstantin Belousov
9316467d05 FFS puts the extended attributes blocks at the negative blocks for the
vnode, from -1 down. When vinvalbuf(vp, V_ALT) is done for the vnode, it
incorrectly does vm_object_page_remove(0, 0), removing all pages from
the underlying vm object, not only the pages that back the extended
attributes data.

Change vinvalbuf() to not remove any pages from the object when
V_NORMAL or V_ALT are specified. Instead, the only in-tree caller
in ffs_inode.c:ffs_truncate() that specifies V_ALT explicitely
removes the corresponding page range. The V_NORMAL caller
does vnode_pager_setsize(vp, 0) immediately after the call to
vinvalbuf(V_NORMAL) already.

Reported by:	csjp
Reviewed by:	ups
MFC after:	3 weeks
2009-01-20 11:27:45 +00:00
Konstantin Belousov
df86ccf642 If unmount of the ffs mp failed, reinitialize the extended attributes
for the mp, and restart them if autostart is enabled.

Reported and tested by:	pho
Reviewed by:	rwatson
MFC after:	3 weeks
2009-01-08 12:48:27 +00:00
Doug Ambrisko
f1c1cdbb9c For now on every 10 cyclinder groups flush the buffer cache to free
up space.  If the buffer cache fills up then the disk systems can
grind to a halt.  Better tuning can be figured out later.

Tested by:	Tim, others and work
Reviewed by:	Kostik Belousov
PR:		128832
2008-11-13 17:40:21 +00:00
Attilio Rao
83b3bdbc8a Improve VFS locking:
- Implement real draining for vfs consumers by not relying on the
  mnt_lock and using instead a refcount in order to keep track of lock
  requesters.
- Due to the change above, remove the mnt_lock lockmgr because it is now
  useless.
- Due to the change above, vfs_busy() is no more linked to a lockmgr.
  Change so its KPI by removing the interlock argument and defining 2 new
  flags for it: MBF_NOWAIT which basically replaces the LK_NOWAIT of the
  old version (which was unlinked from the lockmgr alredy) and
  MBF_MNTLSTLOCK which provides the ability to drop the mountlist_mtx
  once the mnt interlock is held (ability still desired by most consumers).
- The stub used into vfs_mount_destroy(), that allows to override the
  mnt_ref if running for more than 3 seconds, make it totally useless.
  Remove it as it was thought to work into older versions.
  If a problem of "refcount held never going away" should appear, we will
  need to fix properly instead than trust on such hackish solution.
- Fix a bug where returning (with an error) from dounmount() was still
  leaving the MNTK_MWAIT flag on even if it the waiters were actually
  woken up. Just a place in vfs_mount_destroy() is left because it is
  going to recycle the structure in any case, so it doesn't matter.
- Remove the markercnt refcount as it is useless.

This patch modifies VFS ABI and breaks KPI for vfs_busy() so manpages and
__FreeBSD_version will be modified accordingly.

Discussed with:	kib
Tested by:	pho
2008-11-02 10:15:42 +00:00
Edward Tomasz Napierala
15bc6b2bd8 Introduce accmode_t. This is required for NFSv4 ACLs - it will be neccessary
to add more V* constants, and the variables changed by this patch were often
being assigned to mode_t variables, which is 16 bit.

Approved by:	rwatson (mentor)
2008-10-28 13:44:11 +00:00
Dag-Erling Smørgrav
e11e3f187d Fix a number of style issues in the MALLOC / FREE commit. I've tried to
be careful not to fix anything that was already broken; the NFSv4 code is
particularly bad in this respect.
2008-10-23 20:26:15 +00:00
Dag-Erling Smørgrav
1ede983cc9 Retire the MALLOC and FREE macros. They are an abomination unto style(9).
MFC after:	3 months
2008-10-23 15:53:51 +00:00
Konstantin Belousov
016f98f947 Assert that v_holdcnt is non-zero before entering lockmgr in vn_lock
and ffs_lock. This cannot catch situations where holdcnt is incremented
not by curthread, but I think it is useful.

Reviewed by:	tegge, attilio
Tested by:	pho
MFC after:	2 weeks
2008-10-20 10:11:33 +00:00
Konstantin Belousov
4560452f01 Sync up summary information for cylinder groups while data is already
in memory during snapshot creation. This improves the results of the
background fsck.

Submitted by: tegge
MFC after: 1 week
2008-10-13 14:05:01 +00:00
Attilio Rao
0d7935fd01 Remove the struct thread unuseful argument from bufobj interface.
In particular following functions KPI results modified:
- bufobj_invalbuf()
- bufsync()

and BO_SYNC() "virtual method" of the buffer objects set.
Main consumers of bufobj functions are affected by this change too and,
in particular, functions which changed their KPI are:
- vinvalbuf()
- g_vfs_close()

Due to the KPI breakage, __FreeBSD_version will be bumped in a later
commit.

As a side note, please consider just temporary the 'curthread' argument
passing to VOP_SYNC() (in bufsync()) as it will be axed out ASAP

Reviewed by:	kib
Tested by:	Giovanni Trematerra <giovanni dot trematerra at gmail dot com>
2008-10-10 21:23:50 +00:00
John Baldwin
f888634792 Enable shared lookups on UFS. There are some remaining issues with forced
unmounts, but those are in the VFS lookup code are not UFS specific.

Tested by:	pho, kris
2008-09-24 18:53:04 +00:00
Konstantin Belousov
6fecb4e41e Suspend the write operations on the UFS filesystem being unmounted or
remounted from rw to ro.

Proposed and reviewed by:  tegge
In collaboration with:	pho
MFC after:	 1 month
2008-09-16 11:55:53 +00:00
Konstantin Belousov
2814d5ba5f When attempt is made to suspend a filesystem that is already syspended,
wait until the current suspension is lifted instead of silently returning
success immediately. The consequences of calling vfs_write() resume when
not owning the suspension are not well-defined at best.

Add the vfs_susp_clean() mount method to be called from
vfs_write_resume(). Set it to process_deferred_inactive() for ffs, and
stop calling it manually.

Add the thread flag TDP_IGNSUSP that allows to bypass the suspension
point in the vn_start_write. It is intended for use by VFS in the
situations where the suspender want to do some i/o requiring calls to
vn_start_write(), and this i/o cannot be done later.

Reviewed by:	tegge
In collaboration with:	pho
MFC after:	 1 month
2008-09-16 11:51:06 +00:00
Konstantin Belousov
52dfc8d7da Add the ffs structures introspection functions for ddb.
Show the b_dep value for the buffer in the show buffer command.
Add a comand to dump the dirty/clean buffer list for vnode.

Reviewed by:	tegge
Tested and used by:   pho
MFC after:   1 month
2008-09-16 11:19:38 +00:00
Konstantin Belousov
90446e360c When downgrading the read-write mount to read-only, do_unmount() sets
MNT_RDONLY flag before the VFS_MOUNT() is called. In ufs_inactive()
and ufs_itimes_locked(), UFS verifies whether the fs is read-only by
checking MNT_RDONLY, but this may cause loss of the IN_MODIFIED flag
for inode on the fs being remounted rw->ro.

Introduce UFS_RDONLY() struct ufsmount' method that reports the value
of the fs_ronly. The later is set to 1 only after the remount is
finished.

Reviewed by:	tegge
In collaboration with:	pho
MFC after:	 1 month
2008-09-16 10:59:35 +00:00
Konstantin Belousov
0411d79138 The struct inode *ip supplied to softdep_freefile is not neccessary the
inode having number ino. In r170991, the ip was marked IN_MODIFIED, that
is not quite correct.

Mark only the right inode modified by checking inode number.

Reviewed by:	tegge
In collaboration with:	pho
MFC after:	 1 month
2008-09-16 10:52:25 +00:00
Edward Tomasz Napierala
86a0c0aa7b When calling extattr_check_cred, use V{READ,WRITE}, not I{READ,WRITE}.
Approved by:	rwatson (mentor)
2008-09-03 12:46:09 +00:00
Attilio Rao
59d4932531 Decontextualize vfs_busy(), vfs_unbusy() and vfs_mount_alloc() functions.
Manpages are updated accordingly.

Tested by:	Diego Sardina <siarodx at gmail dot com>
2008-08-31 14:26:08 +00:00
Attilio Rao
0359a12ead Decontextualize the couplet VOP_GETATTR / VOP_SETATTR as the passed thread
was always curthread and totally unuseful.

Tested by: Giovanni Trematerra <giovanni dot trematerra at gmail dot com>
2008-08-28 15:23:18 +00:00
Konstantin Belousov
acd05e468a In ffs_valloc(), ffs_vget() may fail because insmntque() refused to
insert new vnode into the mount vnode list. Then, for the SU-enabled
mount, ffs_vfree could create freefile dependency. This dependency can
hang around forever since inode is not marked as IN_MODIFIED and
correspondingly inodeblock may be not marked as dirty.

After ffs_vget() fails, retry with FFSV_FORCEINSMQ, mark the inode as
modified, and vput() it immediately. Take care of the dup alloc.

Tested by:	pho
Reviewed by:	tegge
MFC after:	1 month
2008-08-28 09:19:50 +00:00
Konstantin Belousov
7b7ed832e4 Softdep code may need to instantiate vnode when processing
dependencies. In particular, it may need this while syncing filesystem
being unmounted. Since during unmount MNTK_NOINSMNTQUE flag is set,
that could sometimes disallow insertion of the vnode into the vnode
mount list, softdep code needs to overwrite the MNTK_NOINSMNTQUE flag.

Create the ffs_vgetf() function that sets the VV_FORCEINSMQ flag for
new vnode and use it consistently from the softdep code instead of
ffs_vget().

Add the retry logic to the softdep_flushfiles() to flush the vnodes
that could be instantiated while flushing softdep dependencies.

Tested by:	pho, kris
Reviewed by:	tegge
MFC after:	1 month
2008-08-28 09:18:20 +00:00
Konstantin Belousov
e792b09be2 Revert r181345.
Move the NULL pointer check to the vfs_deleteopt() function.

Discussed with:	rodrigc
MFC after:	3 days
2008-08-10 12:15:36 +00:00
Konstantin Belousov
a1a917e029 User may do "mount -o snapshot ...", that causes new FFS mount to be
performed with snapshot option, while the mp->mnt_opt is NULL.
Protect against NULL pointer dereference.

Noted by:	Mateusz Guzik <mjguzik gmail com>
MFC after:	3 days
2008-08-06 14:47:19 +00:00
Konstantin Belousov
89672c6337 The ffs_balloc_ufs{1,2} functions call bdwrite() while having several
vnode buffers locked at once. In particular, there are indirect buffers
among locked ones. The bdwrite() may start the flushing to keep dirty
buffer list at the bounds. If any buffer on the dirty list requires
translation from logical to physical block number, code may ends up
trying to lock an indirect buffer already locked in ffs_balloc_ufsX.

Prevent the bdflush() activity when several buffers are locked at once
by setting the TDP_INBDFUSH for the problematic code blocks.

Reported and tested by:	pho, Josef Buchsteiner at Juniper
In collaboration with:	kan
MFC after:	1 month
2008-07-23 14:32:44 +00:00
Pawel Jakub Dawidek
a80d8caa74 Say hi to svn, by simplifing ffs_vget() function a bit - there is no need for
a variable that is used only once.
2008-07-19 22:29:44 +00:00
Craig Rodrigues
8e7a2353ec Fix comments to replace SBSIZE with SBLOCKSIZE, since SBSIZE
was renamed to SBLOCKSIZE in version 1.33

Reviewed by:	mckusick
2008-05-24 20:44:14 +00:00
Craig Rodrigues
fb77e0af12 After converting the "snapshot" mount option to the MNT_SNAPSHOT flag,
delete "snapshot" from the persistent mount options list.
This should fix problems with doing a mount -o snapshot of a file system, followed by
an NFS export of the same file system.

PR:		122833
Reported by:	Leon Kos <leon.kos lecad fs uni-lj si>,
		Jaakko Heinonen <jh saunalahti fi>
MFC after:	1 month
2008-05-24 00:41:32 +00:00
Craig Rodrigues
02a871f1ea For the following mount options, do not perform the string to flag conversions
here, because we already do them further up in vfs_donmount() in vfs_mount.c

async -> MNT_ASYNC
force -> MNT_FORCE
multilabel -> MNT_MULTILABEL
noatime -> MNT_NOATIME
noclusterr -> MNT_NOCLUSTERR
noclusterw -> MNT_NOCLUSTERW

MFC after:  1 month
2008-05-24 00:02:12 +00:00
Attilio Rao
047dd67e96 Optimize lockmgr in order to get rid of the pool mutex interlock, of the
state transitioning flags and of msleep(9) callings.
Use, instead, an algorithm very similar to what sx(9) and rwlock(9)
alredy do and direct accesses to the sleepqueue(9) primitive.

In order to avoid writer starvation a mechanism very similar to what
rwlock(9) uses now is implemented, with the correspective per-thread
shared lockmgrs counter.

This patch also adds 2 new functions to lockmgr KPI: lockmgr_rw() and
lockmgr_args_rw().  These two are like the 2 "normal" versions, but they
both accept a rwlock as interlock.  In order to realize this, the general
lockmgr manager function "__lockmgr_args()" has been implemented through
the generic lock layer. It supports all the blocking primitives, but
currently only these 2 mappers live.

The patch drops the support for WITNESS atm, but it will be probabilly
added soon. Also, there is a little race in the draining code which is
also present in the current CVS stock implementation: if some sharers,
once they wakeup, are in the runqueue they can contend the lock with
the exclusive drainer.  This is hard to be fixed but the now committed
code mitigate this issue a lot better than the (past) CVS version.
In addition assertive KA_HELD and KA_UNHELD have been made mute
assertions because they are dangerous and they will be nomore supported
soon.

In order to avoid namespace pollution, stack.h is splitted into two
parts: one which includes only the "struct stack" definition (_stack.h)
and one defining the KPI.  In this way, newly added _lockmgr.h can
just include _stack.h.

Kernel ABI results heavilly changed by this commit (the now committed
version of "struct lock" is a lot smaller than the previous one) and
KPI results broken by lockmgr_rw() / lockmgr_args_rw() introduction,
so manpages and __FreeBSD_version will be updated accordingly.

Tested by:      kris, pho, jeff, danger
Reviewed by:    jeff
Sponsored by:   Google, Summer of Code program 2007
2008-04-06 20:08:51 +00:00
Konstantin Belousov
57b4252e45 Add the support for the AT_FDCWD and fd-relative name lookups to the
namei(9).

Based on the submission by rdivacky,
	sponsored by Google Summer of Code 2007
Reviewed by:	rwatson, rdivacky
Tested by:	pho
2008-03-31 12:01:21 +00:00
Jeff Roberson
d04963d0f4 - Since rev 1.142 of ffs_snapshot.c the interlock has not been required
to protect the v_lock pointer.  Removing the interlock acquisition
   here allows vn_lock() to proceed without requiring the interlock
   at all.
 - If the lock mutated while we were sleeping on it the interlock has
   been dropped.  It is conceivable that the upper layer code was
   relying on the interlock and LK_NOWAIT to protect the identity or
   state of the vnode while acquiring the lock.  In this case return
   EBUSY rather than trying the new lock to prevent potential races.

Reviewed by:	tegge
2008-03-31 07:55:45 +00:00
Jeff Roberson
9c0cdb8253 - Don't free snapdata structures when they are no longer in use.
Keeping the lockmgr lock valid allows us to switch the v_lock pointer
   in snapshot vnodes between the embedded lockmgr lock and snapdata
   lock without needing the vnode interlock to protect against races
 - Keep unused snapdata structures in a list.
 - Add a function to lock the devvp and allocate a snapdata to it or
   acquire a new one without races.  The old function was safe from
   creation races because we set the mount flag when creating snapshots
   and thus serializing them.  However, it might have been subject to
   destroying races.

Reviewed by:	tegge
2008-03-31 07:47:08 +00:00
John Baldwin
d952ba1bd5 Fix a nit with the 'nofoo' options where 'foo' is mapped to 'nonofoo'
(such as 'atime' vs 'noatime').  The filesystems will always see either
'nofoo' or 'nonofoo', never plain 'foo'.  As such, their list of valid
mount options should include 'nofoo' instead of 'foo'.  With this fix,
you can do 'mount -u -o atime' on a FFS filesystem that isn't marked as
noatime without getting an error.  You can also update a noatime FFS
filesystem mounted via mount(2) (e.g. 6.x /sbin/mount binary) to 'atime'
using nmount(2) (e.g. 7.x /sbin/mount binary).

MFC after:	1 week
Reviewed by:	crodig
2008-03-26 20:48:07 +00:00
Konstantin Belousov
1be222e9df Yield the cpu in the kernel while iterating the list of the
vnodes belonging to the mountpoint. Also, yield when in the
softdep_process_worklist() even when we are not going to sleep due to
buffer drain.

It is believed that the ULE fixed the problem [1], but the yielding
seems to be needed at least for the 4BSD case.

Discussed:	on stable@, with bde
Reviewed by:	tegge, jeff [1]
MFC after:	2 weeks
2008-03-23 13:45:24 +00:00