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2009-07-21NFSv4: Fix a problem whereby a buggy server can oops the kernelTrond Myklebust
We just had a case in which a buggy server occasionally returns the wrong attributes during an OPEN call. While the client does catch this sort of condition in nfs4_open_done(), and causes the nfs4_atomic_open() to return -EISDIR, the logic in nfs_atomic_lookup() is broken, since it causes a fallback to an ordinary lookup instead of just returning the error. When the buggy server then returns a regular file for the fallback lookup, the VFS allows the open, and bad things start to happen, since the open file doesn't have any associated NFSv4 state. The fix is firstly to return the EISDIR/ENOTDIR errors immediately, and secondly to ensure that we are always careful when dereferencing the nfs_open_context state pointer. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-07-21NFSv4: Fix an NFSv4 mount regressionTrond Myklebust
Commit 008f55d0e019943323c20a03493a2ba5672a4cc8 (nfs41: recover lease in _nfs4_lookup_root) forces the state manager to always run on mount. This is a bug in the case of NFSv4.0, which doesn't require us to send a setclientid until we want to grab file state. In any case, this is completely the wrong place to be doing state management. Moving that code into nfs4_init_session... Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-07-21NFSv4: Fix an Oops in nfs4_free_lock_stateTrond Myklebust
The oops http://www.kerneloops.org/raw.php?rawid=537858&msgid= appears to be due to the nfs4_lock_state->ls_state field being uninitialised. This happens if the call to nfs4_free_lock_state() is triggered at the end of nfs4_get_lock_state(). The fix is to move the initialisation of ls_state into the allocator. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-07-12headers: smp_lock.h reduxAlexey Dobriyan
* Remove smp_lock.h from files which don't need it (including some headers!) * Add smp_lock.h to files which do need it * Make smp_lock.h include conditional in hardirq.h It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT This will make hardirq.h inclusion cheaper for every PREEMPT=n config (which includes allmodconfig/allyesconfig, BTW) Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-11Revert "fuse: Fix build error" as unnecessaryLinus Torvalds
This reverts commit 097041e576ee3a50d92dd643ee8ca65bf6a62e21. Trond had a better fix, which is the parent of this one ("Fix compile error due to congestion_wait() changes") Requested-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-10fuse: Fix build errorLarry Finger
When building v2.6.31-rc2-344-g69ca06c, the following build errors are found due to missing includes: CC [M] fs/fuse/dev.o fs/fuse/dev.c: In function ‘request_end’: fs/fuse/dev.c:289: error: ‘BLK_RW_SYNC’ undeclared (first use in this function) ... fs/nfs/write.c: In function ‘nfs_set_page_writeback’: fs/nfs/write.c:207: error: ‘BLK_RW_ASYNC’ undeclared (first use in this function) Signed-off-by: Larry Finger@lwfinger.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-10Fix congestion_wait() sync/async vs read/write confusionJens Axboe
Commit 1faa16d22877f4839bd433547d770c676d1d964c accidentally broke the bdi congestion wait queue logic, causing us to wait on congestion for WRITE (== 1) when we really wanted BLK_RW_ASYNC (== 0) instead. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-08headers: mnt_namespace.h reduxAlexey Dobriyan
Fix various silly problems wrt mnt_namespace.h: - exit_mnt_ns() isn't used, remove it - done that, sched.h and nsproxy.h inclusions aren't needed - mount.h inclusion was need for vfsmount_lock, but no longer - remove mnt_namespace.h inclusion from files which don't use anything from mnt_namespace.h Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-22NFS: Correct the NFS mount path when following a referralTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-22NFS: Fix nfs_path() to always return a '/' at the beginning of the pathTrond Myklebust
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-22NFSv4: Replace nfs4_path_walk() with VFS path lookup in a private namespaceTrond Myklebust
As noted in the previous patch, the NFSv4 client mount code currently has several limitations. If the mount path contains symlinks, or referrals, or even if it just contains a '..', then the client code in nfs4_path_walk() will fail with an error. This patch replaces the nfs4_path_walk()-based lookup with a helper function that sets up a private namespace to represent the namespace on the server, then uses the ordinary VFS and NFS path lookup code to walk down the mount path in that namespace. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-22Merge branch 'for-2.6.31' of git://fieldses.org/git/linux-nfsdLinus Torvalds
* 'for-2.6.31' of git://fieldses.org/git/linux-nfsd: (60 commits) SUNRPC: Fix the TCP server's send buffer accounting nfsd41: Backchannel: minorversion support for the back channel nfsd41: Backchannel: cleanup nfs4.0 callback encode routines nfsd41: Remove ip address collision detection case nfsd: optimise the starting of zero threads when none are running. nfsd: don't take nfsd_mutex twice when setting number of threads. nfsd41: sanity check client drc maxreqs nfsd41: move channel attributes from nfsd4_session to a nfsd4_channel_attr struct NFS: kill off complicated macro 'PROC' sunrpc: potential memory leak in function rdma_read_xdr nfsd: minor nfsd_vfs_write cleanup nfsd: Pull write-gathering code out of nfsd_vfs_write nfsd: track last inode only in use_wgather case sunrpc: align cache_clean work's timer nfsd: Use write gathering only with NFSv2 NFSv4: kill off complicated macro 'PROC' NFSv4: do exact check about attribute specified knfsd: remove unreported filehandle stats counters knfsd: fix reply cache memory corruption knfsd: reply cache cleanups ...
2009-06-20nfs41: Move initialization of nfs4_opendata seq_res to nfs4_init_opendata_resBenny Halevy
nfs4_open_recover_helper clears opendata->o_res before calling nfs4_init_opendata_res, thus causing NFSv4.0 OPEN operations to be sent rather than nfsv4.1. Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-18Merge branch 'devel-for-2.6.31' into for-2.6.31Trond Myklebust
Conflicts: fs/nfs/client.c fs/nfs/super.c
2009-06-17nfs: remove unnecessary NFS_INO_INVALID_ACL checksJames Morris
Unless I'm mistaken, NFS_INO_INVALID_ACL is being checked twice during getacl calls (i.e. first via nfs_revalidate_inode() and then by each all site). Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: More "sloppy" parsing problemsChuck Lever
Specifying "port=-5" with the kernel's current mount option parser generates "unrecognized mount option". If "sloppy" is set, this causes the mount to succeed and use the default values; the desired behavior is that, since this is a valid option with an invalid value, the mount should fail, even with "sloppy." To properly handle "sloppy" parsing, we need to distinguish between correct options with invalid values, and incorrect options. We will need to parse integer values by hand, therefore, and not rely on match_token(). For instance, these must all fail with "invalid value": port=12345678 port=-5 port=samuel and not with "unrecognized option," as they do currently. Thus, for the sake of match_token() we need to treat the values for these options as strings, and do the conversion to integers using strict_strtol(). This is basically the same solution we used for the earlier "retry=" fix (commit ecbb3845), except in this case the kernel actually has to parse the value, rather than ignore it. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: Invalid mount option values should always fail, even with "sloppy"Chuck Lever
Ian Kent reports: "I've noticed a couple of other regressions with the options vers and proto option of mount.nfs(8). The commands: mount -t nfs -o vers=<invalid version> <server>:/<path> /<mountpoint> mount -t nfs -o proto=<invalid proto> <server>:/<path> /<mountpoint> both immediately fail. But if the "-s" option is also used they both succeed with the mount falling back to defaults (by the look of it). In the past these failed even when the sloppy option was given, as I think they should. I believe the sloppy option is meant to allow the mount command to still function for mount options (for example in shared autofs maps) that exist on other Unix implementations but aren't present in the Linux mount.nfs(8). So, an invalid value specified for a known mount option is different to an unknown mount option and should fail appropriately." See RH bugzilla 486266. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: Remove unused XDR decoder functionsChuck Lever
Clean up: Remove xdr_decode_fhstatus() and xdr_decode_fhstatus3(), now that they are unused. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: Update MNT and MNT3 reply decoding functionsChuck Lever
Solder xdr_stream-based XDR decoding functions into the in-kernel mountd client that are more careful about checking data types and watching for buffer overflows. The new MNT3 decoder includes support for auth-flavor list decoding. The "_sz" macro for MNT3 replies was missing the size of the file handle. I've added this back, and included the size of the auth flavor array. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: add XDR decoder for mountd version 3 auth-flavor listsChuck Lever
Introduce an xdr_stream-based XDR decoder that can unpack the auth- flavor list returned in a MNT3 reply. The nfs_mount() function's caller allocates an array, and passes the size and a pointer to it. The decoder decodes all the flavors it can into the array, and returns the number of decoded flavors. If the caller is not interested in the auth flavors, it can pass a value of zero as the size of the pre-allocated array. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: add new file handle decoders to in-kernel mountd clientChuck Lever
Introduce xdr_stream-based XDR file handle decoders to the in-kernel mountd client. These are more careful than the existing decoder functions about buffer overflows and data type and range checking. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: Add separate mountd status code decoders for each mountd versionChuck Lever
Introduce data structures and xdr_stream-based decoding functions for unmarshalling mountd status codes properly. Mountd version 3 uses specific standard error return codes that are not errno values and not NFS3ERR_ values. These have a well-defined standard mapping to local errno values. Introduce data structures and a decoder function that map these status codes to local errno values properly. This is new functionality (but not used yet). Version 1 mountd status values are defined by RFC 1094 as UNIX error values (errno values). Errno values on heterogeneous systems do not necessarily match each other. To avoid exposing possibly incorrect errno values to upper layers, the current XDR decoder converts all non-zero MNT version 1 status codes to -EACCES. The OpenGroup XNFS standard provides a mapping similar to but smaller than the version 3 error codes. Implement a decoder that uses the XNFS error codes, replacing the current decoder. For both mountd protocol versions, map unrecognized errors to -EACCES. Finally we introduce a replacement data structure for mnt_fhstatus at this time, which is used by the new XDR decoders. In addition to documenting that the status value returned by the XDR decoders is always an errno, this new structure will be expanded in subsequent patches. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: remove unused function in fs/nfs/mount_clnt.cChuck Lever
Clean up: remove xdr_encode_dirpath() now that it has been replaced. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: Use xdr_stream-based XDR encoder for MNT's dirpath argumentChuck Lever
Check the length of the supplied dirpath, and see that it fits properly in the RPC buffer. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: Clean up MNT program definitionsChuck Lever
Clean up: Relocate MNT program procedure number definitions to the only file that uses them. Relocate the version number definitions, which are shared, to nfs.h. Remove duplicate program number definitions. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: Fix false error return from nfs_callback_up() if ipv6.ko is not availableChuck Lever
Clear "ret" if the error return from svc_create_xprt(AF_INET6) was -EAFNOSUPORT. Otherwise, callback start-up will succeed, but nfs_callback_up() will return -EAFNOSUPPORT anyway, and the first NFSv4 mount attempt after a reboot will fail. Bug introduced by commit f738f517 in 2.6.30-rc1. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: Return error code from nfs_callback_up() to user spaceChuck Lever
If the kernel cannot start the NFSv4 callback service during a mount request, it returns -ENOMEM to user space, resulting in this message: mount.nfs4: Cannot allocate memory Adjust nfs_alloc_client() and nfs_get_client() to pass NFSv4 callback start-up errors back to user space so a less mysterious error message can be displayed by the mount command. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: Do not display the setting of the "intr" mount optionChuck Lever
The "intr" mount option has been deprecated for a while, but /proc/mounts continues to display "nointr" whether "intr" or "nointr" has been specified for a mount point. Since these options do not have any effect, simply do not display them. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17NFS: add support for splice writesSuresh Jayaraman
Adds support for splice writes. It effectively calls generic_file_splice_write() to do the writes. We need not worry about O_APPEND case as the combination of splice() writes and O_APPEND is disallowed. This patch propagates NFS write errors back to the caller. The number of bytes written via splice are being added to NFSIO_NORMALWRITTENBYTES as these are effectively cached writes. Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17Merge commit 'linux-pnfs/nfs41-for-2.6.31' into nfsv41-for-2.6.31Trond Myklebust
2009-06-17nfs41: Backchannel: CB_SEQUENCE validationRicardo Labiaga
Validates the callback's sessionID, the slot number, and the sequence ID. Increments the slot's sequence. Detects replays, but simply prints a debug message (if debugging is enabled since we don't yet implement a duplicate request cache for the backchannel. This should not present a problem, since only idempotent callbacks are currently implemented. Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Backchannel: Be more obvious about the return value] [nfs41: Backchannel: dprink in host order] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: Backchannel: New find_client_with_session()Ricardo Labiaga
Finds the 'struct nfs_client' that matches the server's address, major version number, and session ID. Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: Backchannel: Add a backchannel slot table to the sessionRicardo Labiaga
Defines a new 'struct nfs4_slot_table' in the 'struct nfs4_session' for use by the backchannel. Initializes, resets, and destroys the backchannel slot table in the same manner the forechannel slot table is initialized, reset, and destroyed. The sequenceid for each slot in the backchannel slot table is initialized to 0, whereas the forechannel slotid's sequenceid is set to 1. Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: Backchannel: Refactor nfs4_init_slot_table()Ricardo Labiaga
Generalize nfs4_init_slot_table() so it can be used to initialize the backchannel slot table in addition to the forechannel slot table. Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: Backchannel: Refactor nfs4_reset_slot_table()Ricardo Labiaga
Generalize nfs4_reset_slot_table() so it can be used to reset the backchannel slot table in addition to the forechannel slot table. Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: Backchannel: update cb_sequence args and resultsRicardo Labiaga
Change the type of cs_addr and csr_status to 'struct sockaddr' and '__be32' since the cb_sequence processing function will use existing functionality that expects these types. Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: verify CB_SEQUENCE position in callback compoundBenny Halevy
CB_SEQUENCE must appear first in the callback compound RPC. If it is not the first operation NFS4ERR_SEQUENCE_POS must be returned. If the first operation ni the CB_COMPOUND is not CB_SEQUENCE then NFS4ERR_OP_NOT_IN_SESSION must be returned. Signed-off-by: Ricardo Labiaga <ricardo.labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: refactor op preprocessing out of process_op] Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: cb_sequence xdr implementationBenny Halevy
[nfs41: get rid of READMEM and COPYMEM for callback_xdr.c] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: get rid of READ64 in callback_xdr.c] See http://linux-nfs.org/pipermail/pnfs/2009-June/007846.html Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: cb_sequence proc implementationBenny Halevy
Currently, just free up any referring calls information. Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: fix csr_{,target}highestslotid] Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: cb_sequence protocol level data structuresBenny Halevy
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: consider minorversion in callback_xdr:process_opBenny Halevy
Note that this patch changes the nfsv4.0 behavior also when CONFIG_NFS_V4_1 is not defined where NFS4ERR_MINOR_VERS_MISMATCH will be returned if the client received a CB_COMPOUND with minorversion != 0. Previously, it would have returned NFS4ERR_OP_ILLEGAL for CB_SEQUENCE. (or if the server is broken and sent OP_CB_GETATTR or OP_CB_RECALL with minorversion!=0, they would have been processed normally. Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: refactor op preprocessing out of process_op] See http://linux-nfs.org/pipermail/pnfs/2009-June/007845.html [nfs41: define CB_NOTIFY_DEVICEID as not supported] Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: callback numbers definitionsBenny Halevy
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: decode minorversion 1 cb_compound headerBenny Halevy
decode cb_compound header conforming to http://tools.ietf.org/html/draft-ietf-nfsv4-minorversion1-26 Get rid of cb_compound_hdr_arg.callback_ident callback_ident is not used anywhere so we shouldn't waste any memory to store it. Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: no need to break read_buf in decode_compound_hdr_arg] See http://linux-nfs.org/pipermail/pnfs/2009-June/007844.html Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: store minorversion in cb_compound_hdr_argBenny Halevy
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: Release backchannel resources associated with sessionAndy Adamson
Frees the preallocated backchannel resources that are associated with this session when the session is destroyed. A backchannel is currently created once per session. Destroy the backchannel only when the session is destroyed. Signed-off-by: Ricardo Labiaga <ricardo.labiaga@netapp.com> Signed-off-by: Andy Adamson<andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: Client indicates presence of NFSv4.1 callback channel.Andy Adamson
Set the SESSION4_BACK_CHAN flag to indicate the client supports a backchannel. Signed-off-by: Ricardo Labiaga <ricardo.labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: Setup the backchannelAndy Adamson
The NFS v4.1 callback service has already been setup, and rpc_xprt->serv points to the svc_serv structure describing it. Invoke the xprt_setup_backchannel() initialization to pre- allocate the necessary backchannel structures. Signed-off-by: Ricardo Labiaga <ricardo.labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: change nfs4_put_session(nfs4_session**) to nfs4_destroy_session(nfs_session*)] Signed-off-by: Alexandros Batsakis <Alexandros.Batsakis@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [moved xprt_setup_backchannel from nfs4_init_session to nfs4_init_backchannel] Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: Allow NFSv4 and NFSv4.1 callback services to coexistAndy Adamson
Tracks the nfs_callback_info for both versions, enabling the callback service for v4 and v4.1 to run concurrently and be stopped independently of each other. Signed-off-by: Ricardo Labiaga <ricardo.labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: create a svc_xprt for nfs41 callback thread and use for incoming ↵Benny Halevy
callbacks Signed-off-by: Benny Halevy <bhalevy@panasas.com>
2009-06-17nfs41: Implement NFSv4.1 callback service process.Ricardo Labiaga
nfs41_callback_up() initializes the necessary queues and creates the new nfs41_callback_svc thread. This thread executes the callback service which waits for requests to arrive on the svc_serv->sv_cb_list. NFS41_BC_MIN_CALLBACKS is set to 1 because we expect callbacks to not cause substantial latency. The actual processing of the callback will be implemented as a separate patch. There is only one NFSv4.1 callback service. The first caller of nfs4_callback_up() creates the service, subsequent callers increment a reference count on the service. The service is destroyed when the last caller invokes nfs_callback_down(). The transport needs to hold a reference to the callback service in order to invoke it during callback processing. Currently this reference is only obtained when the service is first created. This is incorrect, since subsequent registrations for other transports will leave the xprt->serv pointer uninitialized, leading to an oops when a callback arrives on the "unreferenced" transport. This patch fixes the problem by ensuring that a reference to the service is saved in xprt->serv, either because the service is created by this invocation to nfs4_callback_up() or by a prior invocation. Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Add a reference to svc_serv during callback service bring up] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Type check arguments of nfs_callback_up] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: save svc_serv in nfs_callback_info] Signed-off-by: Benny Halevy <bhalevy@panasas.com> [Removal of ugly #ifdefs] [nfs41: Update to removal of ugly #ifdefs] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>