The reason this was done was to avoid a race to the root when an
NFS server went down. However a semi-recent change to the way that
the kernel's lookup() routine traverses mount points prevents this.
Rev 1.39 of vfs_lookup.c changed the ordering of locks such that we
aquire a shared lock on the mount point being accessed and then drop
the directory vnode lock before requesting the target lock.
With that in place we no longer need shared locks for NFS to prevent
race to the root lockups.
to set np->n_size back to the desired size again after calling
nfs_meta_setsize(), since it could end up in nfs_loadattrcache() getting
called, which would change n_size back to the value it had before the
truncate request was issued. The result of this bug is that the size info
cached in the nfsnode becomes incorrect, lseek(fd, ofs, SEEK_END) seeks
past the end of the file, stat() returns the wrong size, etc.
PR: 41792
MFC after: 2 weeks
has not been cleaned in the meantime, since this can happen during
a forced unmount. Also add a comment that nfs_removeit() should
really be locking the directory vnode before calling nfs_removerpc().
Reported by: mbr
Tested by: mbr
MFC after: 1 week
VOP_SETATTR() or VOP_GETATTR(); without these locks (a) VFS_DEBUG_LOCKS
will panic, and (b) it may be possible to corrupt entries in the cached
vnode attributes in the nfsnode, since nfsnode attribute cache data is
also protected by the vnode lock.
Approved by: re (jhb)
Pointed out by: VFS_DEBUG_LOCKS
Instead, use the generic vaccess() operation to determine whether
an operation is permitted. This avoids embedding knowledge on
vnode permission bits such as VAPPEND in the NFS client.
PR: kern/46515
vaccess() patch submitted by: "Peter Edwards" <pmedwards@eircom.net>
Approved by: tjr, roberto (mentor)
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.
an if clause was true. Break the two clauses out into seperate statements
since they require different actions.
Reported/Tested by: jake
Spotted by: jhb
- 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
kern/vfs_defaults.c it is wrong for the individual filesystems to use
the std* functions as that prevents override of the default.
Found by: src/tools/tools/vop_table
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)
- 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
nfs_readlink() calls nfs_bioread() which passes in uio_td as the thread
argument to nfs_getcacheblk(). In nfs_getcacheblk() we dereference the
thread pointer to get a process pointer to pass to nfs_sigintr(). This
obviously results in a panic. :)
Rather than change nfs_getcacheblk() to check if the thread pointer is
NULL when calling nfs_sigintr() like other callers do, change
nfs_sigintr() to take a thread as the last argument instead of a
process so none of the callers have to care if the thread is NULL or not.
This is belived to be the only place where a soft reference to a vnode
is held with no sort of hard reference, consequently this change should
allow us to free(9) vnodes from the freelist after properly cleaning
them up.
Reviewed by: dillon
temporary storage. In the old NFS code it wasn't at all clear if
the value of `tl' was used across or after macro calls, but I'm
fairly confident that the convention was to keep its use local.
Each ex-macro function now uses a local version of this variable,
so all of the double-indirection goes away.
The only exception to the `local use' rule for `tl' is nfsm_clget(),
which is left unchanged by this commit.
Reviewed by: peter
commit by Kirk also fixed a softupdates bug that could easily be triggered
by server side NFS.
* An edge case with shared R+W mmap()'s and truncate whereby
the system would inappropriately clear the dirty bits on
still-dirty data. (applicable to all filesystems)
THIS FIX TEMPORARILY DISABLED PENDING FURTHER TESTING.
see vm/vm_page.c line 1641
* The straddle case for VM pages and buffer cache buffers when
truncating. (applicable to NFS client side)
* Possible SMP database corruption due to vm_pager_unmap_page()
not clearing the TLB for the other cpu's. (applicable to NFS
client side but could effect all filesystems). Note: not
considered serious since the corruption occurs beyond the file
EOF.
* When flusing a dirty buffer due to B_CACHE getting cleared,
we were accidently setting B_CACHE again (that is, bwrite() sets
B_CACHE), when we really want it to stay clear after the write
is complete. This resulted in a corrupt buffer. (applicable
to all filesystems but probably only triggered by NFS)
* We have to call vtruncbuf() when ftruncate()ing to remove
any buffer cache buffers. This is still tentitive, I may
be able to remove it due to the second bug fix. (applicable
to NFS client side)
* vnode_pager_setsize() race against nfs_vinvalbuf()... we have
to set n_size before calling nfs_vinvalbuf or the NFS code
may recursively vnode_pager_setsize() to the original value
before the truncate. This is what was causing the user mmap
bus faults in the nfs tester program. (applicable to NFS
client side)
* Fix to softupdates (see ufs/ffs/ffs_inode.c 1.73, commit made
by Kirk).
Testing program written by: Avadis Tevanian, Jr.
Testing program supplied by: jkh / Apple (see Dec2001 posting to freebsd-hackers with Subject 'NFS: How to make FreeBS fall on its face in one easy step')
MFC after: 1 week
to avoid the need for rpc.lockd to perform client locks. Using
this option a user can revert back to using local locks for NFS mounts
like we did before we had rpc.lockd.
- crhold() returns a reference to the ucred whose refcount it bumps.
- crcopy() now simply copies the credentials from one credential to
another and has no return value.
- a new crshared() primitive is added which returns true if a ucred's
refcount is > 1 and false (0) otherwise.
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
a temporary array to store struct buf pointers if the list doesn't
fit in a local array. Usually it frees the array when finished,
but if it jumps to the 'again' label and the new list does fit in
the local array then it can forget to free a previously malloc'd
M_TEMP memory.
Move the free() up a line so that it frees any previously allocated
memory whether or not it needs to malloc a new array.
Reviewed by: dillon
systems were repo-copied from sys/miscfs to sys/fs.
- Renamed the following file systems and their modules:
fdesc -> fdescfs, portal -> portalfs, union -> unionfs.
- Renamed corresponding kernel options:
FDESC -> FDESCFS, PORTAL -> PORTALFS, UNION -> UNIONFS.
- Install header files for the above file systems.
- Removed bogus -I${.CURDIR}/../../sys CFLAGS from userland
Makefiles.
Make 7 filesystems which don't really know about VOP_BMAP rely
on the default vector, rather than more or less complete local
vop_nopbmap() implementations.
VOP_BWRITE() was a hack which made it possible for NFS client
side to use struct buf with non-bio backing.
This patch takes a more general approach and adds a bp->b_op
vector where more methods can be added.
The success of this patch depends on bp->b_op being initialized
all relevant places for some value of "relevant" which is not
easy to determine. For now the buffers have grown a b_magic
element which will make such issues a tiny bit easier to debug.
