Commit Graph

51 Commits

Author SHA1 Message Date
Joe Marcus Clarke
933efde2e5 Add a simple VOP_VPTOCNP implementation for deadfs which returns EBADF.
Reviewed by:	arch
Approved by:	kib
2008-12-12 00:59:36 +00:00
Konstantin Belousov
7f92c4ee02 Below is slightly edited description of the LOR by Tor Egge:
--------------------------
[Deadlock] is caused by a lock order reversal in vfs_lookup(), where
[some] process is trying to lock a directory vnode, that is the parent
directory of covered vnode) while holding an exclusive vnode lock on
covering vnode.

A simplified scenario:

root fs					var fs
/    		A			/    (/var)	D
/var		B			/log (/var/log) E
vfs lock	C			vfs lock	F

Within each file system, the lock order is clear: C->A->B and F->D->E

When traversing across mounts, the system can choose between two lock orders,
but everything must then follow that lock order:

      L1: C->A->B
		|
	        +->F->D->E

      L2: F->D->E
	     |
             +->C->A->B

The lookup() process for namei("/var") mixes those two lock orders:

    VOP_LOOKUP() obtains B while A is held
    vfs_busy() obtains a shared lock on F while A and B are held (follows L1,
    violates L2)
    vput() releases lock on B
    VOP_UNLOCK() releases lock on A
    VFS_ROOT() obtains lock on D while shared lock on F is held
    vfs_unbusy() releases shared lock on F
    vn_lock() obtains lock on A while D is held (violates L1, follows L2)

dounmount() follows L1 (B is locked while F is drained).

Without unmount activity, vfs_busy() will always succeed without blocking
and the deadlock isn't triggered (the system behaves as if L2 is followed).

With unmount, you can get 4 processes in a deadlock:

     p1: holds D, want A (in lookup())
     p2: holds shared lock on F, want D (in VFS_ROOT())
     p3: holds B, want drain lock on F (in dounmount())
     p4: holds A, want B (in VOP_LOOKUP())

You can have more than one instance of p2.

The reversal was introduced in revision 1.81 of src/sys/kern/vfs_lookup.c and
MFCed to revision 1.80.2.1, probably to avoid a cascade of vnode locks when nfs
servers are dead (VFS_ROOT() just hangs) spreading to the root fs root vnode.

- Tor Egge

To fix the LOR, ups@ noted that when crossing the mount point, ni_dvp
is actually not used by the callers of namei. Thus, placeholder deadfs
vnode vp_crossmp is introduced that is filled into ni_dvp.

Idea by:	ups
Reviewed by:	tegge, ups, jeff, rwatson (mac interaction)
Tested by:	Peter Holm
MFC after:	2 weeks
2007-01-22 11:25:22 +00:00
Jeff Roberson
578abc8e54 - Deadfs should not use the std GETWRITEMOUNT routine. Add one that always
returns NULL.

MFC After:	1 week
2006-02-22 06:11:59 +00:00
Jeff Roberson
3100b70037 - Deadfs may now use the standard vop lock, get rid of dead_lock().
- We no longer have to take the XLOCK state into consideration in any
   routines.

Sponsored by:	Isilon Systems, Inc.
2005-03-13 12:06:20 +00:00
Poul-Henning Kamp
4d8ac58b05 Introduce vx_wait{l}() and use it instead of home-rolled versions. 2005-02-17 10:49:51 +00:00
Poul-Henning Kamp
83c6439714 Whitespace in vop_vector{} initializations. 2005-01-13 18:59:48 +00:00
Poul-Henning Kamp
63f89abf4a Change the generated VOP_ macro implementations to improve type checking
and KASSERT coverage.

After this check there is only one "nasty" cast in this code but there
is a KASSERT to protect against the wrong argument structure behind
that cast.

Un-inlining the meat of VOP_FOO() saves 35kB of text segment on a typical
kernel with no change in performance.

We also now run the checking and tracing on VOP's which have been layered
by nullfs, umapfs, deadfs or unionfs.

    Add new (non-inline) VOP_FOO_AP() functions which take a "struct
    foo_args" argument and does everything the VOP_FOO() macros
    used to do with checks and debugging code.

    Add KASSERT to VOP_FOO_AP() check for argument type being
    correct.

    Slim down VOP_FOO() inline functions to just stuff arguments
    into the struct foo_args and call VOP_FOO_AP().

    Put function pointer to VOP_FOO_AP() into vop_foo_desc structure
    and make VCALL() use it instead of the current offsetoff() hack.

    Retire vcall() which implemented the offsetoff()

    Make deadfs and unionfs use VOP_FOO_AP() calls instead of
    VCALL(), we know which specific call we want already.

    Remove unneeded arguments to VCALL() in nullfs and umapfs bypass
    functions.

    Remove unused vdesc_offset and VOFFSET().

    Generally improve style/readability of the generated code.
2005-01-13 07:53:01 +00:00
Warner Losh
d167cf6f3a /* -> /*- for copyright notices, minor format tweaks as necessary 2005-01-06 18:10:42 +00:00
Poul-Henning Kamp
aec0fb7b40 Back when VOP_* was introduced, we did not have new-style struct
initializations but we did have lofty goals and big ideals.

Adjust to more contemporary circumstances and gain type checking.

	Replace the entire vop_t frobbing thing with properly typed
	structures.  The only casualty is that we can not add a new
	VOP_ method with a loadable module.  History has not given
	us reason to belive this would ever be feasible in the the
	first place.

	Eliminate in toto VOCALL(), vop_t, VNODEOP_SET() etc.

	Give coda correct prototypes and function definitions for
	all vop_()s.

	Generate a bit more data from the vnode_if.src file:  a
	struct vop_vector and protype typedefs for all vop methods.

	Add a new vop_bypass() and make vop_default be a pointer
	to another struct vop_vector.

	Remove a lot of vfs_init since vop_vector is ready to use
	from the compiler.

	Cast various vop_mumble() to void * with uppercase name,
	for instance VOP_PANIC, VOP_NULL etc.

	Implement VCALL() by making vdesc_offset the offsetof() the
	relevant function pointer in vop_vector.  This is disgusting
	but since the code is generated by a script comparatively
	safe.  The alternative for nullfs etc. would be much worse.

	Fix up all vnode method vectors to remove casts so they
	become typesafe.  (The bulk of this is generated by scripts)
2004-12-01 23:16:38 +00:00
Poul-Henning Kamp
6fde64c778 Mechanically change prototypes for vnode operations to use the new typedefs. 2004-12-01 12:24:41 +00:00
Poul-Henning Kamp
9c83534dd8 Make VOP_BMAP return a struct bufobj for the underlying storage device
instead of a vnode for it.

The vnode_pager does not and should not have any interest in what
the filesystem uses for backend.

(vfs_cluster doesn't use the backing store argument.)
2004-11-15 09:18:27 +00:00
Warner Losh
f36cfd49ad Remove advertising clause from University of California Regent's
license, per letter dated July 22, 1999 and email from Peter Wemm,
Alan Cox and Robert Watson.

Approved by: core, peter, alc, rwatson
2004-04-07 20:46:16 +00:00
Nate Lawson
99648386d3 Finish cleanup of vprint() which was begun with changing v_tag to a string.
Remove extraneous uses of vop_null, instead defering to the default op.
Rename vnode type "vfs" to the more descriptive "syncer".
Fix formatting for various filesystems that use vop_print.
2003-03-03 19:15:40 +00:00
Poul-Henning Kamp
bc9d8a9a37 Fix comments and one resulting code confusion about the type of the
"command" argument to VOP_IOCTL.

Spotted by:	FlexeLint.
2002-10-16 08:04:11 +00:00
Poul-Henning Kamp
37c841831f Be consistent about "static" functions: if the function is marked
static in its prototype, mark it static at the definition too.

Inspired by:    FlexeLint warning #512
2002-09-28 17:15:38 +00:00
Nate Lawson
86ed6d45ac Remove any VOP_PRINT that redundantly prints the tag.
Move lockmgr_printinfo() into vprint() for everyone's benefit.

Suggested by: bde
2002-09-18 20:42:04 +00:00
Nate Lawson
06be2aaa83 Remove all use of vnode->v_tag, replacing with appropriate substitutes.
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)
2002-09-14 09:02:28 +00:00
Jeff Roberson
e6e370a7fe - Replace v_flag with v_iflag and v_vflag
- 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
2002-08-04 10:29:36 +00:00
Poul-Henning Kamp
ef41ad17bd Use vop_panic() instead of rolling our own. 2002-05-02 19:13:44 +00:00
Alfred Perlstein
11caded34f Remove __P. 2002-03-19 22:20:14 +00:00
Mark Murray
fb919e4d5a Undo part of the tangle of having sys/lock.h and sys/mutex.h included in
other "system" header files.

Also help the deprecation of lockmgr.h by making it a sub-include of
sys/lock.h and removing sys/lockmgr.h form kernel .c files.

Sort sys/*.h includes where possible in affected files.

OK'ed by:	bde (with reservations)
2001-05-01 08:13:21 +00:00
Bosko Milekic
9ed346bab0 Change and clean the mutex lock interface.
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)
2001-02-09 06:11:45 +00:00
Eivind Eklund
e3c4036b18 Give vop_mmap an untimely death. The opportunity to give it a timely
death timed out in 1996.
2000-11-01 17:57:24 +00:00
Jason Evans
a18b1f1d4d Convert lockmgr locks from using simple locks to using mutexes.
Add lockdestroy() and appropriate invocations, which corresponds to
lockinit() and must be called to clean up after a lockmgr lock is no
longer needed.
2000-10-04 01:29:17 +00:00
Poul-Henning Kamp
ed6aff7387 Remove unneeded <sys/buf.h> includes.
Due to some interesting cpp tricks in lockmgr, the LINT kernel shrinks
by 924 bytes.
2000-04-18 15:15:39 +00:00
Peter Wemm
c3aac50f28 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +00:00
Bruce Evans
1e1c37f1cd Return ENOTTY instead of EBADF for ioctls on dead vnodes. This fixes
tcsetpgrp() on controlling terminals that are no longer associated
with the session of the calling process, not to mention ioctl.2.
1998-11-22 09:19:07 +00:00
Bruce Evans
4e9a89772a Enabled Lite2 fix for reading from dead ttys. 1998-08-23 11:43:29 +00:00
Garrett Wollman
1cbbd625cc Add support for poll(2) on files. vop_nopoll() now returns POLLNVAL
if one of the new poll types is requested; hopefully this will not break
any existing code.  (This is done so that programs have a dependable
way of determining whether a filesystem supports the extended poll types
or not.)

The new poll types added are:

	POLLWRITE - file contents may have been modified
	POLLNLINK - file was linked, unlinked, or renamed
	POLLATTRIB - file's attributes may have been changed
	POLLEXTEND - file was extended

Note that the internal operation of poll() means that it is impossible
for two processes to reliably poll for the same event (this could
be fixed but may not be worth it), so it is not possible to rewrite
`tail -f' to use poll at this time.
1997-12-15 03:09:59 +00:00
Bruce Evans
1cd52ec333 Don't include <sys/lock.h> in headers when only `struct simplelock' is
required.  Fixed everything that depended on the pollution.
1997-12-05 19:55:52 +00:00
Poul-Henning Kamp
dba3870c10 VFS interior redecoration.
Rename vn_default_error to vop_defaultop all over the place.
Move vn_bwrite from vfs_bio.c to vfs_default.c and call it vop_stdbwrite.
Use vop_null instead of nullop.
Move vop_nopoll from vfs_subr.c to vfs_default.c
Move vop_sharedlock from vfs_subr.c to vfs_default.c
Move vop_nolock from vfs_subr.c to vfs_default.c
Move vop_nounlock from vfs_subr.c to vfs_default.c
Move vop_noislocked from vfs_subr.c to vfs_default.c
Use vop_ebadf instead of *_ebadf.
Add vop_defaultop for getpages on master vnode in MFS.
1997-10-26 20:55:39 +00:00
Poul-Henning Kamp
e9565321ea VFS clean up "hekto commit"
1.  Add defaults for more VOPs
        VOP_LOCK        vop_nolock
        VOP_ISLOCKED    vop_noislocked
        VOP_UNLOCK      vop_nounlock
    and remove direct reference in filesystems.

2.  Rename the nfsv2 vnop tables to improve sorting order.
1997-10-16 22:01:05 +00:00
Poul-Henning Kamp
987f569678 Another VFS cleanup "kilo commit"
1.  Remove VOP_UPDATE, it is (also) an UFS/{FFS,LFS,EXT2FS,MFS}
    intereface function, and now lives in the ufsmount structure.

2.  Remove VOP_SEEK, it was unused.

3.  Add mode default vops:

    VOP_ADVLOCK          vop_einval
    VOP_CLOSE            vop_null
    VOP_FSYNC            vop_null
    VOP_IOCTL            vop_enotty
    VOP_MMAP             vop_einval
    VOP_OPEN             vop_null
    VOP_PATHCONF         vop_einval
    VOP_READLINK         vop_einval
    VOP_REALLOCBLKS      vop_eopnotsupp

    And remove identical functionality from filesystems

4.   Add vop_stdpathconf, which returns the canonical stuff.  Use
     it in the filesystems.  (XXX: It's probably wrong that specfs
     and fifofs sets this vop, shouldn't it come from the "host"
     filesystem, for instance ufs or cd9660 ?)

5.   Try to make system wide VOP functions have vop_* names.

6.   Initialize the um_* vectors in LFS.

(Recompile your LKMS!!!)
1997-10-16 20:32:40 +00:00
Poul-Henning Kamp
cec0f20ce7 VFS mega cleanup commit (x/N)
1.  Add new file "sys/kern/vfs_default.c" where default actions for
    VOPs go. Implement proper defaults for ABORTOP, BWRITE, LEASE,
    POLL, REVOKE and STRATEGY.  Various stuff spread over the entire
    tree belongs here.

2.  Change VOP_BLKATOFF to a normal function in cd9660.

3.  Kill VOP_BLKATOFF, VOP_TRUNCATE, VOP_VFREE, VOP_VALLOC.  These
    are private interface functions between UFS and the underlying
    storage manager layer (FFS/LFS/MFS/EXT2FS).  The functions now
    live in struct ufsmount instead.

4.  Remove a kludge of VOP_ functions in all filesystems, that did
    nothing but obscure the simplicity and break the expandability.
    If a filesystem doesn't implement VOP_FOO, it shouldn't have an
    entry for it in its vnops table.  The system will try to DTRT
    if it is not implemented.  There are still some cruft left, but
    the bulk of it is done.

5.  Fix another VCALL in vfs_cache.c (thanks Bruce!)
1997-10-16 10:50:27 +00:00
Poul-Henning Kamp
6a525123aa Hmm, realign the vnops into two columns. 1997-10-15 10:05:29 +00:00
Poul-Henning Kamp
539ef70c2d Stylistic overhaul of vnops tables.
1. Remove comment stating the blatantly obvious.
        2. Align in two columns.
        3. Sort all but the default element alphabetically.
        4. Remove XXX comments pointing out entries not needed.
1997-10-15 09:22:02 +00:00
Peter Wemm
a6aeade2c4 Convert select -> poll.
Delete 'always succeed' select/poll handlers, replaced with generic call.
Flag missing vnode op table entries.
1997-09-14 02:58:12 +00:00
Bruce Evans
e4ba6a82b0 Removed unused #includes. 1997-09-02 20:06:59 +00:00
Peter Wemm
6875d25465 Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.
1997-02-22 09:48:43 +00:00
John Dyson
996c772f58 This is the kernel Lite/2 commit. There are some requisite userland
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.

The system boots and can mount UFS filesystems.

Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
		Mount_std mounts will not work until the getfsent
		library routine is changed.

Reviewed by:	various people
Submitted by:	Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
Jordan K. Hubbard
1130b656e5 Make the long-awaited change from $Id$ to $FreeBSD$
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore.  This update would have been
insane otherwise.
1997-01-14 07:20:47 +00:00
Poul-Henning Kamp
a20e0ea8d7 staticize. 1995-12-02 17:14:34 +00:00
Bruce Evans
dace5f55ca Removed unsed function dead_nullop().
Converted incomplete function declarations to prototypes.
1995-11-11 03:36:07 +00:00
Bruce Evans
f57e65478d Introduced a type `vop_t' for vnode operation functions and used
it 1138 times (:-() in casts and a few more times in declarations.
This change is null for the i386.

The type has to be `typedef int vop_t(void *)' and not `typedef
int vop_t()' because `gcc -Wstrict-prototypes' warns about the
latter.  Since vnode op functions are called with args of different
(struct pointer) types, neither of these function types is any use
for type checking of the arg, so it would be preferable not to use
the complete function type, especially since using the complete
type requires adding 1138 casts to avoid compiler warnings and
another 40+ casts to reverse the function pointer conversions before
calling the functions.
1995-11-09 08:17:23 +00:00
John Dyson
c83ebe7781 Added VOP_GETPAGES/VOP_PUTPAGES and also the "backwards" block count
for VOP_BMAP.  Updated affected filesystems...
1995-09-04 00:21:16 +00:00
Poul-Henning Kamp
b18375bc71 Cosmetics: added a #include and a static prototype to silence gcc. 1994-10-08 22:37:00 +00:00
David Greenman
824789192c Use tsleep() rather than sleep so that 'ps' is more informative about
the wait.
1994-10-06 21:07:04 +00:00
Garrett Wollman
c901836c14 Implemented loadable VFS modules, and made most existing filesystems
loadable.  (NFS is a notable exception.)
1994-09-21 03:47:43 +00:00
David Greenman
3c4dd3568f Added $Id$ 1994-08-02 07:55:43 +00:00
Rodney W. Grimes
26f9a76710 The big 4.4BSD Lite to FreeBSD 2.0.0 (Development) patch.
Reviewed by:	Rodney W. Grimes
Submitted by:	John Dyson and David Greenman
1994-05-25 09:21:21 +00:00