src-test2/sys/fs/nullfs/null_subr.c, branch stable/5 FreeBSD source tree https://cgit-dev.freebsd.org/src-test2/atom?h=stable%2F5 2005-01-31T23:27:04Z MFC: /*- and related license changes 2005-01-31T23:27:04Z Warner Losh imp@FreeBSD.org 2005-01-31T23:27:04Z urn:sha1:c9769f3ab5327a99909391e070c143e92ddc43ec Update for the KDB framework: 2004-07-10T21:20:11Z Marcel Moolenaar marcel@FreeBSD.org 2004-07-10T21:20:11Z urn:sha1:4ea4f1f97ea5212549efbb882c2e8859b19b4254 o Call kdb_enter() instead of Debugger(). o Make debugging code conditional upon KDB instead of DDB. Remove advertising clause from University of California Regent's 2004-04-07T20:46:16Z Warner Losh imp@FreeBSD.org 2004-04-07T20:46:16Z urn:sha1:f36cfd49adb62472fd7009ecd4f0927c126ff785 license, per letter dated July 22, 1999 and email from Peter Wemm, Alan Cox and Robert Watson. Approved by: core, peter, alc, rwatson MFp4: Fix two bugs causing possible deadlocks or panics, and one nit: 2003-06-17T08:52:45Z Tim J. Robbins tjr@FreeBSD.org 2003-06-17T08:52:45Z urn:sha1:549398753af7c4d529442200659794c1847bbd70 - Emulate lock draining (LK_DRAIN) in null_lock() to avoid deadlocks when the vnode is being recycled. - Don't allow null_nodeget() to return a nullfs vnode from the wrong mount when multiple nullfs's are mounted. It's unclear why these checks were removed in null_subr.c 1.35, but they are definitely necessary. Without the checks, trying to unmount a nullfs mount will erroneously return EBUSY, and forcibly unmounting with -f will cause a panic. - Bump LOG2_SIZEVNODE up to 8, since vnodes are >256 bytes now. The old value (7) didn't cause any problems, but made the hash algorithm suboptimal. These changes fix nullfs enough that a parallel buildworld succeeds. Submitted by: tegge (partially; LK_DRAIN) Tested by: kris Back out M_* changes, per decision of the TRB. 2003-02-19T05:47:46Z Warner Losh imp@FreeBSD.org 2003-02-19T05:47:46Z urn:sha1:a163d034fadcfb4a25ca34a2ba5f491c47b6ff69 Approved by: trb Remove M_TRYWAIT/M_WAITOK/M_WAIT. Callers should use 0. 2003-01-21T08:56:16Z Alfred Perlstein alfred@FreeBSD.org 2003-01-21T08:56:16Z urn:sha1:44956c9863dc03344b03bdf6a83acf4e743f8e50 Merge M_NOWAIT/M_DONTWAIT into a single flag M_NOWAIT. Regularize the vop_stdlock'ing protocol across all the filesystems 2002-10-14T03:20:36Z Kirk McKusick mckusick@FreeBSD.org 2002-10-14T03:20:36Z urn:sha1:a5b65058d5e43141777953576267ecf12476e715 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. - Use vrefcnt() where it is safe to do so instead of doing direct and 2002-09-25T02:32:42Z Jeff Roberson jeff@FreeBSD.org 2002-09-25T02:32:42Z urn:sha1:4d93c0be1feae950a60b86e638dd4384f3da8dc8 unlocked accesses to v_usecount. - Lock access to the buf lists in the various sync routines. interlock locking could be avoided almost entirely in leaf filesystems if the fsync function had a generic helper. Remove all use of vnode->v_tag, replacing with appropriate substitutes. 2002-09-14T09:02:28Z Nate Lawson njl@FreeBSD.org 2002-09-14T09:02:28Z urn:sha1:06be2aaa8320ba839a837d20e35f35c3efdf7587 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) Fix a race during null node creation between relookuping the hash and 2002-06-13T21:49:09Z Semen Ustimenko semenu@FreeBSD.org 2002-06-13T21:49:09Z urn:sha1:1cfdefbb9f162da9aa9c045f07394f49aaef1db8 adding vnode to hash. The fix is to use atomic hash-lookup-and-add-if- not-found operation. The odd thing is that this race can't happen actually because the lowervp vnode is locked exclusively now during the whole process of null node creation. This must be thought as a step toward shared lookups. Also remove vp->v_mount checks when looking for a match in the hash, as this is the vestige. Also add comments and cosmetic changes.