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2006-09-22NFS: nfs_lookup - don't hash dentry when optimising away the lookupTrond Myklebust
If the open intents tell us that a given lookup is going to result in a, exclusive create, we currently optimize away the lookup call itself. The reason is that the lookup would not be atomic with the create RPC call, so why do it in the first place? A problem occurs, however, if the VFS aborts the exclusive create operation after the lookup, but before the call to create the file/directory: in this case we will end up with a hashed negative dentry in the dcache that has never been looked up. Fix this by only actually hashing the dentry once the create operation has been successfully completed. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Fix Oops in pmap_getport_doneTrond Myklebust
There is no guarantee that the parent task still exists when we exit from the portmapper. Save the xprt instead. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Add refcounting to the struct rpc_xprtTrond Myklebust
In a subsequent patch, this will allow the portmapper to take a reference to the rpc_xprt for which it is updating the port number, fixing an Oops. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Clean up soft task error handlingTrond Myklebust
- Ensure that the task aborts the RPC call only when it has actually timed out. - Ensure that req->rq_majortimeo is initialised correctly. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Handle ENETUNREACH, EHOSTUNREACH and EHOSTDOWN socket errorsTrond Myklebust
In case of any of the above errors occuring, delay for 3 seconds, then handle as if it were a timeout error. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: rpc_delay() should not clobber the rpc_task->tk_statusTrond Myklebust
Doing so prevents stuff like call_encode() from working correctly. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22Fix a referral error Oopsandros@citi.umich.edu
Fix an oops when the referral server is not responding. Check the error return from nfs4_set_client() in nfs4_create_referral_server. Signed-off-by: Andy Adamson <andros@citi.umich.edu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: NFS_ROOT should use the new rpc_create APIChuck Lever
Teach NFS_ROOT to use the new rpc_create API instead of the old two-call API for creating an RPC transport. Test plan: Compile the kernel with the NFS client build-in, and set CONFIG_NFS_ROOT. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Fix up compiler warnings on 64-bit platforms in client.cDavid Howells
Fix up warnings from compiling on ppc64. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Make rpc_mkpipe() take the parent dentry as an argumentTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFSv4: Fix a use-after-free issue with the nfs server.Trond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22Add a real API for dealing with blk_congestion_wait()Trond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Use cached page as buffer for NFS symlink requestsChuck Lever
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>
2006-09-22NFS: copy symlinks into page cache before sending NFS SYMLINK requestChuck Lever
Currently the NFS client does not cache symlinks it creates. They get cached only when the NFS client reads them back from the server. Copy the symlink into the page cache before sending it. Test plan: Connectathon, all NFS versions. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Fix double d_drop in nfs_instantiate() error pathChuck Lever
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>
2006-09-22NFS: remove a no-longer-needed error check in nfs_symlink()Chuck Lever
In the early days of NFS, there was no duplicate reply cache on the server. Thus retransmitted non-idempotent requests often found that the request had already completed on the server. To avoid passing an unanticipated return code to unsuspecting applications, NFS clients would often shunt error codes that implied the request had been retried but already completed. Thanks to NFS over TCP, duplicate reply caches on the server, and network performance and reliability improvements, it is safe to remove such checks. Test plan: None. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: export new RPC client functions with _GPLChuck Lever
This patch is optional. It has been suggested that the RPC client internal functions used by upper layer protocols (such as NFS) be exported via EXPORT_SYMBOL_GPL. This patch does that. Test plan: Compile kernel with CONFIG_NFS enabled as a module. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Eliminate xprt_create_proto and rpc_create_clientChuck Lever
The two function call API for creating a new RPC client is now obsolete. Remove it. Also, remove an unnecessary check to see whether the caller is capable of using privileged network services. The kernel RPC client always uses a privileged ephemeral port by default; callers are responsible for checking the authority of users to make use of any RPC service, or for specifying that a nonprivileged port is acceptable. Test plan: Repeated runs of Connectathon locking suite. Check network trace to ensure correctness of NLM requests and replies. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Convert RPC portmapper to use new rpc_create() APIChuck Lever
Replace xprt_create_proto/rpc_create_client calls in pmap_clnt.c with new rpc_create() API. Test plan: Repeated runs of Connectathon locking suite. Check network trace for proper PMAP calls and replies. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFSD: Convert NFS server callback logic to use new rpc_create APIChuck Lever
Replace xprt_create_proto/rpc_create_client call in NFS server callback functions to use new rpc_create() API. Test plan: NFSv4 delegation functionality tests. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Convert NFS client to use new rpc_create() APIChuck Lever
Convert NFS client mount logic to use rpc_create() instead of the old xprt_create_proto/rpc_create_client API. Test plan: Mount stress tests. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22LOCKD: Convert to use new rpc_create() APIChuck Lever
Replace xprt_create_proto/rpc_create_client with new rpc_create() interface in the Network Lock Manager. Note that the semantics of NLM transports is now "hard" instead of "soft" to provide a better guarantee that lock requests will get to the server. Test plan: Repeated runs of Connectathon locking suite. Check network trace to ensure NLM requests are working correctly. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: use sockaddr + size when creating remote transport endpointsChuck Lever
Prepare for more generic transport endpoint handling needed by transports that might use different forms of addressing, such as IPv6. Introduce a single function call to replace the two-call xprt_create_proto/rpc_create_client API. Define a new rpc_create_args structure that allows callers to pass in remote endpoint addresses of varying length. Test-plan: Compile kernel with CONFIG_NFS enabled. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Clean-up after previous patches.Chuck Lever
Remove some unused macros related to accessing an RPC peer address Test plan: Compile kernel with CONFIG_NFS option enabled. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Use "sockaddr_storage" for storing RPC client's remote peer addressChuck Lever
IPv6 addresses are big (128 bytes). Now that no RPC client consumers treat the addr field in rpc_xprt structs as an opaque, and access it only via the API calls, we can safely widen the field in the rpc_xprt struct to accomodate larger addresses. Test plan: Compile kernel with CONFIG_NFS enabled. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Teach rpc_pipe.c to use new rpc_peeraddr() APIChuck Lever
Hide the details of how the RPC client stores remote peer addresses from the RPC pipefs implementation. Test plan: Connectathon with Kerberos 5 authentication. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Create API for displaying remote peer addressChuck Lever
Provide an API for formatting the remote peer address for printing without exposing its internal structure. The address could be dynamic, so we support a function call to get the address rather than reading it straight out of a structure. Test-plan: Destructive testing (unplugging the network temporarily). Probably need to rig a server where certain services aren't running, or that returns an error for some typical operation. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: add xprt switch API for printing formatted remote peer addressesChuck Lever
Add a new method to the transport switch API to provide a way to convert the opaque contents of xprt->addr to a human-readable string. Test plan: Compile kernel with CONFIG_NFS enabled. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: remove extraneous header inclusionsChuck Lever
include/linux/sunrpc/clnt.h already includes include/linux/sunrpc/xprt.h. We can remove xprt.h from source files that already include clnt.h. Likewise include/linux/sunrpc/timer.h. Test plan: Compile kernel with CONFIG_NFS enabled. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Teach the RPC portmapper to use the new rpc_peeraddr() API.Chuck Lever
Hide the details of how the RPC client stores remote peer addresses from the RPC portmapper. Test plan: Destructive testing (unplugging the network temporarily). Connectathon with UDP and TCP. NFSv2/3 and NFSv4 mounting should be carefully checked. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22LOCKD: Teach lockd to use the new rpc_peeraddr() APIChuck Lever
Hide the details of how the RPC client stores remote peer addresses from the Network Lock Manager. Test plan: Destructive testing (unplugging the network temporarily). Connectathon with UDP and TCP. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: create API for getting remote peer addressChuck Lever
Provide an API for retrieving the remote peer address without allowing direct access to the rpc_xprt struct. Test-plan: Compile kernel with CONFIG_NFS enabled. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Introduce transport switch callout for pluggable rpcbindChuck Lever
Introduce a clean transport switch API for plugging in different types of rpcbind mechanisms. For instance, rpcbind can cleanly replace the existing portmapper client, or a transport can choose to implement RPC binding any way it likes. Test plan: Destructive testing (unplugging the network temporarily). Connectathon with UDP and TCP. NFSv2/3 and NFSv4 mounting should be carefully checked. Probably need to rig a server where certain services aren't running, or that returns an error for some typical operation. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Support for RPC child tasks no longer neededChuck Lever
The previous patches removed the last user of RPC child tasks, so we can remove support for child tasks from net/sunrpc/sched.c now. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Clean-up after recent changes to sunrpc/pmap_clnt.cChuck Lever
Add comments for external functions, use modern function definition style, and fix up dprintk formatting. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Make RPC portmapper use per-transport storageChuck Lever
Move connection and bind state that was maintained in the rpc_clnt structure to the rpc_xprt structure. This will allow the creation of a clean API for plugging in different types of bind mechanisms. This brings improvements such as the elimination of a single spin lock to control serialization for all in-kernel RPC binding. A set of per-xprt bitops is used to serialize tasks during RPC binding, just like it now works for making RPC transport connections. Test-plan: Destructive testing (unplugging the network temporarily). Connectathon with UDP and TCP. NFSv2/3 and NFSv4 mounting should be carefully checked. Probably need to rig a server where certain services aren't running, or that returns an error for some typical operation. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22SUNRPC: Create a helper to tell whether a transport is boundChuck Lever
Hide the contents and format of xprt->addr by eliminating direct uses of the xprt->addr.sin_port field. This change is required to support alternate RPC host address formats (eg IPv6). Test-plan: Destructive testing (unplugging the network temporarily). Repeated runs of Connectathon locking suite with UDP and TCP. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Fix nfs_alloc_client()Trond Myklebust
The scheme to indicate which services have been started up appears to be seriously broken. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Ensure NFSv2/v3 mounts respect the NFS_MOUNT_SECFLAVOUR flagTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Secure the roots of the NFS subtrees in a shared superblockDavid Howells
Invoke security_d_instantiate() on root dentries after allocating them with dentry_alloc_anon(). Normally dentry_alloc_root() would do that, but we don't call that as we don't want to assign a name to the root dentry at this point (we may discover the real name later). Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Fix error handlingDavid Howells
Fix an error handling problem: nfs_put_client() can be given a NULL pointer if nfs_free_server() is asked to destroy a partially initialised record. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Add server and volume lists to /procDavid Howells
Make two new proc files available: /proc/fs/nfsfs/servers /proc/fs/nfsfs/volumes The first lists the servers with which we are currently dealing (struct nfs_client), and the second lists the volumes we have on those servers (struct nfs_server). Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Share NFS superblocks per-protocol per-server per-FSIDDavid Howells
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>
2006-09-22NFS: Start rpciod in server common managementDavid Howells
Start rpciod in the server common (nfs_client struct) management code rather than in the superblock management code. This means we only need to "start" it once per server instead of once per superblock. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Eliminate client_sys in favour of cl_rpcclientDavid Howells
Eliminate nfs_server::client_sys in favour of nfs_client::cl_rpcclient as we only really need one per server that we're talking to since it doesn't have any security on it. The retransmission management variables are also moved to the common struct as they're required to set up the cl_rpcclient connection. The NFS2/3 client and client_acl connections are thenceforth derived by cloning the cl_rpcclient connection and post-applying the authorisation flavour. The code for setting up the initial common connection has been moved to client.c as nfs_create_rpc_client(). All the NFS program definition tables are also moved there as that's where they're now required rather than super.c. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Move rpc_ops from nfs_server to nfs_clientDavid Howells
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>
2006-09-22NFS: Make better use of inode* dereferencing macrosDavid Howells
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>
2006-09-22NFS: Maintain a common server record for NFS2/3 as well as for NFS4David Howells
Maintain a common server record for NFS2/3 as well as for NFS4 so that common stuff can be moved there from struct nfs_server. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Add extra const qualifiersDavid Howells
Add some extra const qualifiers into NFS. Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-09-22NFS: Use the dentry superblock directly in nfs_statfs()David Howells
Use the nominated dentry's superblock directly in the NFS statfs() op to get a file handle, rather than using s_root (which will become a dummy dentry in a future patch). Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>