This patch removes redundant RPC inode references from PipeFS. These places are
actually where pipes operations are performed.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Generally, pipe data is used only for pipes, and thus allocating space for it
on every RPC inode allocation is redundant. This patch splits private SUNRPC
PipeFS pipe data and inode, makes pipe data allocated only for pipe inodes.
This patch is also is a next step towards to to removing PipeFS inode
references from kernel code other than PipeFS itself.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currenly, inode i_lock is used to provide concurrent access to SUNPRC PipeFS
pipes. It looks redundant, since now other use of inode is present in most of
these places and thus can be easely replaced, which will allow to remove most
of inode references from PipeFS code. This is a first step towards to removing
PipeFS inode references from kernel code other than PipeFS itself.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch adds debug messages for notification events.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

During per-net pipes creation and destruction we have to make sure, that pipefs
sb exists for the whole creation/destruction cycle. This is done by using
special mutex which controls pipefs sb reference on network namespace context.
Helper consists of two parts: first of them (rpc_get_dentry_net) searches for
dentry with specified name and returns with mutex taken on success. When pipe
creation or destructions is completed, caller should release this mutex by
rpc_put_dentry_net call.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We have modules (like, pNFS blocklayout module) which creates pipes on
rpc_pipefs. Thus we need per-net operations for them. To make it possible we
require appropriate super block. So we have to put sb link on network namespace
context. Note, that it's not strongly required to create pipes in per-net
operations. IOW, if pipefs wasn't mounted yet, that no sb link reference will
present on network namespace and in this case we need just need to pass through
pipe creation. Pipe dentry will be created during pipefs mount notification.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

In all places, where pipefs dentries are created, only directory inode is
actually required to create new dentry. And all this directories has root
pipefs dentry as their parent. So we actually don't need this pipefs mount
point at all if some pipefs lookup method will be provided.
IOW, all we really need is just superblock and simple lookup method to find
root's child dentry with appropriate name. And this patch introduces this
method.
Note, that no locking implemented in rpc_d_lookup_sb(). So it can be used only
in case of assurance, that pipefs superblock still exist. IOW, we can use this
method only in pipefs mount-umount notification subscribers callbacks.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

They will be used to notify subscribers about pipefs superblock creation and
destruction.
Subcribers will have to create their dentries on passed superblock on mount
event and destroy otherwise.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We want to be sure that network namespace is still alive while we have pipefs
mounted.
This will be required later, when RPC pipefs will be mounting only from
user-space context.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This is the initial step of RPC pipefs virtualization. It changes nothing to
current pipefs behaviour except that mount of pipefs in other than init_net
network namespace context will provide only root tree. No other dentries will
be visible.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch-set was created in context of clone of git branch:
git://git.linux-nfs.org/projects/trondmy/nfs-2.6.git.

v2:
1) Rebased of current repo state (i.e. all commits were pulled before apply)

I feel it is ready for inclusion if no objections will appear.

SUNRPC pipefs non-exclusive pipe creation code looks obsolete. IOW, as I see
it, all pipes are creating with unique full path and only once.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Seeing that just about every destructor got that INIT_LIST_HEAD() copied into
it, there is no point whatsoever keeping this INIT_LIST_HEAD in inode_init_once();
the cost of taking it into inode_init_always() will be negligible for pipes
and sockets and negative for everything else.  Not to mention the removal of
boilerplate code from ->destroy_inode() instances...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The same function is used by idmap, gss and blocklayout code. Make it
generic.
Signed-off-by: NPeng Tao <peng_tao@emc.com>
Signed-off-by: NJim Rees <rees@umich.edu>
Cc: stable@kernel.org [3.0]
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

sunrpc implements the rpc_pipefs filesystem type.
Add the alias to have the module requested automatically by the kernel
when the filesystem is mounted.
Signed-off-by: NMichal Schmidt <mschmidt@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Make the case labels the same indent as the switch.

git diff -w shows 80 column line reflowing.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reduce some branches and memory accesses in dcache lookup by adding dentry
flags to indicate common d_ops are set, rather than having to check them.
This saves a pointer memory access (dentry->d_op) in common path lookup
situations, and saves another pointer load and branch in cases where we
have d_op but not the particular operation.

Patched with:

git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

RCU free the struct inode. This will allow:

- Subsequent store-free path walking patch. The inode must be consulted for
  permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
  to take i_lock no longer need to take sb_inode_list_lock to walk the list in
  the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
  page lock to follow page->mapping.

The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.

In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.

The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

Change d_delete from a dentry deletion notification to a dentry caching
advise, more like ->drop_inode. Require it to be constant and idempotent,
and not take d_lock. This is how all existing filesystems use the callback
anyway.

This makes fine grained dentry locking of dput and dentry lru scanning
much simpler.
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

On Tue, 2010-12-14 at 16:58 +0800, Mi Jinlong wrote:
> Hi,
>
> When testing NFSv4 at RHEL6 with kernel 2.6.32, I got a kernel panic
> at NFS client's __rpc_create_common function.
>
> The panic place is:
>   rpc_mkpipe
>     __rpc_lookup_create()          <=== find pipefile *idmap*
>     __rpc_mkpipe()                 <=== pipefile is *idmap*
>       __rpc_create_common()
>        ******  BUG_ON(!d_unhashed(dentry)); ******    *panic*
>
> It means that the dentry's d_flags have be set DCACHE_UNHASHED,
> but it should not be set here.
>
> Is someone known this bug? or give me some idea?
>
> A reproduce program is append, but it can't reproduce the bug every time.
> the export is: "/nfsroot       *(rw,no_root_squash,fsid=0,insecure)"
>
> And the panic message is append.
>
> ============================================================================
> #!/bin/sh
>
> LOOPTOTAL=768
> LOOPCOUNT=0
> ret=0
>
> while [ $LOOPCOUNT -ne $LOOPTOTAL ]
> do
> 	((LOOPCOUNT += 1))
> 	service nfs restart
> 	/usr/sbin/rpc.idmapd
> 	mount -t nfs4 127.0.0.1:/ /mnt|| return 1;
> 	ls -l /var/lib/nfs/rpc_pipefs/nfs/*/
> 	umount /mnt
> 	echo $LOOPCOUNT
> done
>
> ===============================================================================
> Code: af 60 01 00 00 89 fa 89 f0 e8 64 cf 89 f0 e8 5c 7c 64 cf 31 c0 8b 5c 24 10 8b
> 74 24 14 8b 7c 24 18 8b 6c 24 1c 83 c4 20 c3 <0f> 0b eb fc 8b 46 28 c7 44 24 08 20
> de ee f0 c7 44 24 04 56 ea
> EIP:[<f0ee92ea>] __rpc_create_common+0x8a/0xc0 [sunrpc] SS:ESP 0068:eccb5d28
> ---[ end trace 8f5606cd08928ed2]---
> Kernel panic - not syncing: Fatal exception
> Pid:7131, comm: mount.nfs4 Tainted: G     D   -------------------2.6.32 #1
> Call Trace:
>  [<c080ad18>] ? panic+0x42/0xed
>  [<c080e42c>] ? oops_end+0xbc/0xd0
>  [<c040b090>] ? do_invalid_op+0x0/0x90
>  [<c040b10f>] ? do_invalid_op+0x7f/0x90
>  [<f0ee92ea>] ? __rpc_create_common+0x8a/0xc0[sunrpc]
>  [<f0edc433>] ? rpc_free_task+0x33/0x70[sunrpc]
>  [<f0ed6508>] ? prc_call_sync+0x48/0x60[sunrpc]
>  [<f0ed656e>] ? rpc_ping+0x4e/0x60[sunrpc]
>  [<f0ed6eaf>] ? rpc_create+0x38f/0x4f0[sunrpc]
>  [<c080d80b>] ? error_code+0x73/0x78
>  [<f0ee92ea>] ? __rpc_create_common+0x8a/0xc0[sunrpc]
>  [<c0532bda>] ? d_lookup+0x2a/0x40
>  [<f0ee94b1>] ? rpc_mkpipe+0x111/0x1b0[sunrpc]
>  [<f10a59f4>] ? nfs_create_rpc_client+0xb4/0xf0[nfs]
>  [<f10d6c6d>] ? nfs_fscache_get_client_cookie+0x1d/0x50[nfs]
>  [<f10d3fcb>] ? nfs_idmap_new+0x7b/0x140[nfs]
>  [<c05e76aa>] ? strlcpy+0x3a/0x60
>  [<f10a60ca>] ? nfs4_set_client+0xea/0x2b0[nfs]
>  [<f10a6d0c>] ? nfs4_create_server+0xac/0x1b0[nfs]
>  [<c04f1400>] ? krealloc+0x40/0x50
>  [<f10b0e8b>] ? nfs4_remote_get_sb+0x6b/0x250[nfs]
>  [<c04f14ec>] ? kstrdup+0x3c/0x60
>  [<c0520739>] ? vfs_kern_mount+0x69/0x170
>  [<f10b1a3c>] ? nfs_do_root_mount+0x6c/0xa0[nfs]
>  [<f10b1b47>] ? nfs4_try_mount+0x37/0xa0[nfs]
>  [<f10afe6d>] ? nfs4_validate_text_mount_data+-x7d/0xf0[nfs]
>  [<f10b1c42>] ? nfs4_get_sb+0x92/0x2f0
>  [<c0520739>] ? vfs_kern_mount+0x69/0x170
>  [<c05366d2>] ? get_fs_type+0x32/0xb0
>  [<c052089f>] ? do_kern_mount+0x3f/0xe0
>  [<c053954f>] ? do_mount+0x2ef/0x740
>  [<c0537740>] ? copy_mount_options+0xb0/0x120
>  [<c0539a0e>] ? sys_mount+0x6e/0xa0

Hi,

Does the following patch fix the problem?

Cheers
  Trond

--------------------------
SUNRPC: Fix a BUG in __rpc_create_common

From: Trond Myklebust <Trond.Myklebust@netapp.com>

Mi Jinlong reports:

When testing NFSv4 at RHEL6 with kernel 2.6.32, I got a kernel panic
at NFS client's __rpc_create_common function.

The panic place is:
  rpc_mkpipe
      __rpc_lookup_create()          <=== find pipefile *idmap*
      __rpc_mkpipe()                 <=== pipefile is *idmap*
        __rpc_create_common()
         ******  BUG_ON(!d_unhashed(dentry)); ****** *panic*

The test is wrong: we can find ourselves with a hashed negative dentry here
if the idmapper tried to look up the file before we got round to creating
it.

Just replace the BUG_ON() with a d_drop(dentry).
Reported-by: NMi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Instead of always assigning an increasing inode number in new_inode
move the call to assign it into those callers that actually need it.
For now callers that need it is estimated conservatively, that is
the call is added to all filesystems that do not assign an i_ino
by themselves.  For a few more filesystems we can avoid assigning
any inode number given that they aren't user visible, and for others
it could be done lazily when an inode number is actually needed,
but that's left for later patches.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The sunrpc cache_ioctl function does not need the big kernel lock
because it uses its own queue_lock already.

rpc_pipe_ioctl apparently should be using i_lock like the other
operations on the pipe file descriptor do.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

There is a race between rpc_info_open and rpc_release_client()
in that nothing stops a process from opening the file after
the clnt->cl_kref goes to zero.

Fix this by using atomic_inc_unless_zero()...
Reported-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

If rpc_queue_upcall() adds a new upcall to the rpci->pipe list just
after rpc_pipe_release calls rpc_purge_list(), but before it calls
gss_pipe_release (as rpci->ops->release_pipe(inode)), then the latter
will free a message without deleting it from the rpci->pipe list.

We will be left with a freed object on the rpc->pipe list.  Most
frequent symptoms are kernel crashes in rpc.gssd system calls on the
pipe in question.
Reported-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

Pushdown the bkl to rpc_pipe_ioctl.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Nfs <linux-nfs@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>

__rpc_lookup_create() can return ERR_PTR(-ENOMEM).
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

kill_litter_super() from ->kill_sb() will take care of the junk

The function name must be followed by a space, hypen, space, and a
short description.
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix kernel-doc notation (& warnings) in sunrpc/rpc_pipe.c.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The NFSv4 and NFSv4.1 protocols both allow for the redirection of a client
from one server to another in order to support filesystem migration and
replication. For full protocol support, we need to add the ability to
convert a DNS host name into an IP address that we can feed to the RPC
client.

We'll reuse the sunrpc cache, now that it has been converted to work with
rpc_pipefs.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We want the channel to be a regular file, so that we don't need to supply
rpc_pipe_ops.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

In order to allow rpc_pipefs to create directories with different types of
subtrees, it is useful to allow the caller to customise the subtree filling
process.
In order to do so, we separate out the parts which are specific to making
an RPC client directory, and put them in a separate helper, then we convert
the process of filling the directory contents into a callback.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

There is still a little wart or two there: Since we've already got a
vfsmount, we might as well pass that in to rpc_create_client_dir.
Another point is that if we open code __rpc_lookup_path() here, then we can
avoid looking up the entire parent directory path over and over again: it
doesn't change.

Also get rid of rpc_clnt->cl_pathname, since it has no users...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Factor out the code that does lookups from the code that actually creates
the directory.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This reflects the fact that rpc_mkdir() as it stands today, can only create
a RPC client type directory.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move the files[] array closer to rpc_fill_super()
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>