I ran into a curious issue when a lock is being canceled. The
cancellation results in a lock request to the vfs layer instead of an
unlock request. This is particularly insidious when the process that
owns the lock is exiting. In that case, sometimes the erroneous lock is
applied AFTER the process has entered zombie state, preventing the lock
from ever being released. Eventually other processes block on the lock
causing a slow degredation of the system. In the 2.6.16 kernel this was
investigated on, the problem is compounded by the fact that the cl_sem
is held while blocking on the vfs lock, which results in most processes
accessing the nfs file system in question hanging.
In more detail, here is how the situation occurs:
first _nfs4_do_setlk():
static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *fl, int reclaim)
...
ret = nfs4_wait_for_completion_rpc_task(task);
if (ret == 0) {
...
} else
data->cancelled = 1;
then nfs4_lock_release():
static void nfs4_lock_release(void *calldata)
...
if (data->cancelled != 0) {
struct rpc_task *task;
task = nfs4_do_unlck(&data->fl, data->ctx, data->lsp,
data->arg.lock_seqid);
The problem is the same file_lock that was passed in to _nfs4_do_setlk()
gets passed to nfs4_do_unlck() from nfs4_lock_release(). So the type is
still F_RDLCK or FWRLCK, not F_UNLCK. At some point, when cancelling the
lock, the type needs to be changed to F_UNLCK. It seemed easiest to do
that in nfs4_do_unlck(), but it could be done in nfs4_lock_release().
The concern I had with doing it there was if something still needed the
original file_lock, though it turns out the original file_lock still
needs to be modified by nfs4_do_unlck() because nfs4_do_unlck() uses the
original file_lock to pass to the vfs layer, and a copy of the original
file_lock for the RPC request.
It seems like the simplest solution is to force all situations where
nfs4_do_unlck() is being used to result in an unlock, so with that in
mind, I made the following change:
Signed-off-by: Frank Filz <ffilzlnx@us.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Rely on nfs4_try_open_cached() when appropriate.
Also fix an RCU violation in _nfs4_do_open_reclaim()
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If we already have a stateid with the correct open mode for a given file,
then we can reuse that stateid instead of re-issuing an OPEN call without
violating the close-to-open caching semantics.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We should not be calling open() on an inode that has a delegation unless
we're doing a reclaim.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This ensures that nfs4_open_release() and nfs4_open_confirm_release()
can now handle an eventual delegation that was returned with out open.
As such, it fixes a delegation "leak" when the user breaks out of an open
call.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently we do not check for the FMODE_EXEC flag as we should. For that
particular case, we need to perform an ACCESS call to the server in order
to check that the file is executable.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The Linux NFS4 client simply skips over the bitmask in an O_EXCL open
call and so it doesn't bother to reset any fields that may be holding
the verifier. This patch has us save the first two words of the bitmask
(which is all the current client has #defines for). The client then
later checks this bitmask and turns on the appropriate flags in the
sattr->ia_verify field for the following SETATTR call.
This patch only currently checks to see if the server used the atime
and mtime slots for the verifier (which is what the Linux server uses
for this). I'm not sure of what other fields the server could
reasonably use, but adding checks for others should be trivial.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
nfs4_do_close() does not currently have any way to ensure that the user
won't attempt to unmount the partition while the asynchronous RPC call
is completing. This again may cause Oopses in nfs_update_inode().
Add a vfsmount argument to nfs4_close_state to ensure that the partition
remains mounted while we're closing the file.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
A number of race conditions may currently ensue if the user presses ^C
and then unmounts the partition while an asynchronous open() is in
progress.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
- fs/nfs/dir.c:610:8: warning: symbol 'nfs_llseek_dir' was not declared.
Should it be static?
- fs/nfs/dir.c:636:5: warning: symbol 'nfs_fsync_dir' was not declared.
Should it be static?
- fs/nfs/write.c:925:19: warning: symbol 'req' shadows an earlier one
- fs/nfs/write.c:61:6: warning: symbol 'nfs_commit_rcu_free' was not
declared. Should it be static?
- fs/nfs/nfs4proc.c:793:5: warning: symbol 'nfs4_recover_expired_lease'
was not declared. Should it be static?
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* 'server-cluster-locking-api' of git://linux-nfs.org/~bfields/linux:
gfs2: nfs lock support for gfs2
lockd: add code to handle deferred lock requests
lockd: always preallocate block in nlmsvc_lock()
lockd: handle test_lock deferrals
lockd: pass cookie in nlmsvc_testlock
lockd: handle fl_grant callbacks
lockd: save lock state on deferral
locks: add fl_grant callback for asynchronous lock return
nfsd4: Convert NFSv4 to new lock interface
locks: add lock cancel command
locks: allow {vfs,posix}_lock_file to return conflicting lock
locks: factor out generic/filesystem switch from setlock code
locks: factor out generic/filesystem switch from test_lock
locks: give posix_test_lock same interface as ->lock
locks: make ->lock release private data before returning in GETLK case
locks: create posix-to-flock helper functions
locks: trivial removal of unnecessary parentheses
The file_lock argument to ->lock is used to return the conflicting lock
when found. There's no reason for the filesystem to return any private
information with this conflicting lock, but nfsv4 is.
Fix nfsv4 client, and modify locks.c to stop calling fl_release_private
for it in this case.
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Cc: "Trond Myklebust" <Trond.Myklebust@netapp.com>"
The ACL that the server sets may not be exactly the one we set--for
example, it may silently turn off bits that it does not support. So we
should remove any cached ACL so that any subsequent request for the ACL
will go to the server.
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Many struct inode_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Run this:
#!/bin/sh
for f in $(grep -Erl "\([^\)]*\) *k[cmz]alloc" *) ; do
echo "De-casting $f..."
perl -pi -e "s/ ?= ?\([^\)]*\) *(k[cmz]alloc) *\(/ = \1\(/" $f
done
And then go through and reinstate those cases where code is casting pointers
to non-pointers.
And then drop a few hunks which conflicted with outstanding work.
Cc: Russell King <rmk@arm.linux.org.uk>, Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Steven French <sfrench@us.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Maintaining two parallel ways of doing synchronous writes is rather
pointless. This patch gets rid of the legacy nfs_writepage_sync(), and
replaces it with the faster asynchronous writes.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Remove use of the Big Kernel Lock around calls to rpc_call_sync.
Signed-off-by: Frank Filz <ffilz@us.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Acked-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
on-the-wire data is big-endian
[in large part pulled from Alexey's patch]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Acked-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Coverity spotted a superfluous error check in nfs4_open_revalidate(). Remove
it.
Coverity: #cid 847
Test plan:
Code inspection; another pass through Coverity.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Retry a few times before we give up: the error is usually due to ordering
issues with asynchronous RPC calls.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Now that we have a copy of the symlink path in the page cache, we can pass
a struct page down to the XDR routines instead of a string buffer.
Test plan:
Connectathon, all NFS versions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the LOOKUP or GETATTR in nfs_instantiate fail, nfs_instantiate will do a
d_drop before returning. But some callers already do a d_drop in the case
of an error return. Make certain we do only one d_drop in all error paths.
This issue was introduced because over time, the symlink proc API diverged
slightly from the create/mkdir/mknod proc API. To prevent other coding
mistakes of this type, change the symlink proc API to be more like
create/mkdir/mknod and move the nfs_instantiate call into the symlink proc
routines so it is used in exactly the same way for create, mkdir, mknod,
and symlink.
Test plan:
Connectathon, all versions of NFS.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The attached patch makes NFS share superblocks between mounts from the same
server and FSID over the same protocol.
It does this by creating each superblock with a false root and returning the
real root dentry in the vfsmount presented by get_sb(). The root dentry set
starts off as an anonymous dentry if we don't already have the dentry for its
inode, otherwise it simply returns the dentry we already have.
We may thus end up with several trees of dentries in the superblock, and if at
some later point one of anonymous tree roots is discovered by normal filesystem
activity to be located in another tree within the superblock, the anonymous
root is named and materialises attached to the second tree at the appropriate
point.
Why do it this way? Why not pass an extra argument to the mount() syscall to
indicate the subpath and then pathwalk from the server root to the desired
directory? You can't guarantee this will work for two reasons:
(1) The root and intervening nodes may not be accessible to the client.
With NFS2 and NFS3, for instance, mountd is called on the server to get
the filehandle for the tip of a path. mountd won't give us handles for
anything we don't have permission to access, and so we can't set up NFS
inodes for such nodes, and so can't easily set up dentries (we'd have to
have ghost inodes or something).
With this patch we don't actually create dentries until we get handles
from the server that we can use to set up their inodes, and we don't
actually bind them into the tree until we know for sure where they go.
(2) Inaccessible symbolic links.
If we're asked to mount two exports from the server, eg:
mount warthog:/warthog/aaa/xxx /mmm
mount warthog:/warthog/bbb/yyy /nnn
We may not be able to access anything nearer the root than xxx and yyy,
but we may find out later that /mmm/www/yyy, say, is actually the same
directory as the one mounted on /nnn. What we might then find out, for
example, is that /warthog/bbb was actually a symbolic link to
/warthog/aaa/xxx/www, but we can't actually determine that by talking to
the server until /warthog is made available by NFS.
This would lead to having constructed an errneous dentry tree which we
can't easily fix. We can end up with a dentry marked as a directory when
it should actually be a symlink, or we could end up with an apparently
hardlinked directory.
With this patch we need not make assumptions about the type of a dentry
for which we can't retrieve information, nor need we assume we know its
place in the grand scheme of things until we actually see that place.
This patch reduces the possibility of aliasing in the inode and page caches for
inodes that may be accessed by more than one NFS export. It also reduces the
number of superblocks required for NFS where there are many NFS exports being
used from a server (home directory server + autofs for example).
This in turn makes it simpler to do local caching of network filesystems, as it
can then be guaranteed that there won't be links from multiple inodes in
separate superblocks to the same cache file.
Obviously, cache aliasing between different levels of NFS protocol could still
be a problem, but at least that gives us another key to use when indexing the
cache.
This patch makes the following changes:
(1) The server record construction/destruction has been abstracted out into
its own set of functions to make things easier to get right. These have
been moved into fs/nfs/client.c.
All the code in fs/nfs/client.c has to do with the management of
connections to servers, and doesn't touch superblocks in any way; the
remaining code in fs/nfs/super.c has to do with VFS superblock management.
(2) The sequence of events undertaken by NFS mount is now reordered:
(a) A volume representation (struct nfs_server) is allocated.
(b) A server representation (struct nfs_client) is acquired. This may be
allocated or shared, and is keyed on server address, port and NFS
version.
(c) If allocated, the client representation is initialised. The state
member variable of nfs_client is used to prevent a race during
initialisation from two mounts.
(d) For NFS4 a simple pathwalk is performed, walking from FH to FH to find
the root filehandle for the mount (fs/nfs/getroot.c). For NFS2/3 we
are given the root FH in advance.
(e) The volume FSID is probed for on the root FH.
(f) The volume representation is initialised from the FSINFO record
retrieved on the root FH.
(g) sget() is called to acquire a superblock. This may be allocated or
shared, keyed on client pointer and FSID.
(h) If allocated, the superblock is initialised.
(i) If the superblock is shared, then the new nfs_server record is
discarded.
(j) The root dentry for this mount is looked up from the root FH.
(k) The root dentry for this mount is assigned to the vfsmount.
(3) nfs_readdir_lookup() creates dentries for each of the entries readdir()
returns; this function now attaches disconnected trees from alternate
roots that happen to be discovered attached to a directory being read (in
the same way nfs_lookup() is made to do for lookup ops).
The new d_materialise_unique() function is now used to do this, thus
permitting the whole thing to be done under one set of locks, and thus
avoiding any race between mount and lookup operations on the same
directory.
(4) The client management code uses a new debug facility: NFSDBG_CLIENT which
is set by echoing 1024 to /proc/net/sunrpc/nfs_debug.
(5) Clone mounts are now called xdev mounts.
(6) Use the dentry passed to the statfs() op as the handle for retrieving fs
statistics rather than the root dentry of the superblock (which is now a
dummy).
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Move the rpc_ops from the nfs_server struct to the nfs_client struct as they're
common to all server records of a particular NFS protocol version.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Make better use of inode* dereferencing macros to hide dereferencing chains
(including NFS_PROTO and NFS_CLIENT).
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Add some extra const qualifiers into NFS.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Generalise the nfs_client structure by:
(1) Moving nfs_client to a more general place (nfs_fs_sb.h).
(2) Renaming its maintenance routines to be non-NFS4 specific.
(3) Move those maintenance routines to a new non-NFS4 specific file (client.c)
and move the declarations to internal.h.
(4) Make nfs_find/get_client() take a full sockaddr_in to include the port
number (will be required for NFS2/3).
(5) Make nfs_find/get_client() take the NFS protocol version (again will be
required to differentiate NFS2, 3 & 4 client records).
Also:
(6) Make nfs_client construction proceed akin to inodes, marking them as under
construction and providing a function to indicate completion.
(7) Make nfs_get_client() wait interruptibly if it finds a client that it can
share, but that client is currently being constructed.
(8) Make nfs4_create_client() use (6) and (7) instead of locking cl_sem.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
