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2016-07-25Merge branch 'pnfs'Trond Myklebust1-13/+7
2016-07-24pNFS: Remove redundant pnfs_mark_layout_returned_if_empty()Trond Myklebust1-13/+0
That's already being taken care of in pnfs_layout_remove_lseg(). Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24pNFS: Cleanup - don't open code pnfs_mark_layout_stateid_invalid()Trond Myklebust1-0/+2
Ensure nfs42_layoutstat_done() layoutget don't open code layout stateid invalidation. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-24pNFS: LAYOUTRETURN should only update the stateid if the layout is validTrond Myklebust1-0/+5
If the layout was completely returned, then ignore the returned layout stateid. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-18pNFS: Don't mark the inode as revalidated if a LAYOUTCOMMIT is outstandingTrond Myklebust1-0/+7
We know that the attributes will need updating if there is still a LAYOUTCOMMIT outstanding. Reported-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-06pNFS: pnfs_layoutcommit_outstanding() is no longer used when !CONFIG_NFS_V4_1Trond Myklebust1-7/+0
Cleanup... Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-05-26pnfs: pnfs_update_layout needs to consider if strict iomode checking is onTom Haynes1-0/+1
As flexfiles has FF_FLAGS_NO_READ_IO, there is a need to generically support enforcing that a IOMODE_RW segment will not allow READ I/O. Signed-off-by: Tom Haynes <loghyr@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-17pnfs: rework LAYOUTGET retry handlingJeff Layton1-5/+1
There are several problems in the way a stateid is selected for a LAYOUTGET operation: We pick a stateid to use in the RPC prepare op, but that makes it difficult to serialize LAYOUTGETs that use the open stateid. That serialization is done in pnfs_update_layout, which occurs well before the rpc_prepare operation. Between those two events, the i_lock is dropped and reacquired. pnfs_update_layout can find that the list has lsegs in it and not do any serialization, but then later pnfs_choose_layoutget_stateid ends up choosing the open stateid. This patch changes the client to select the stateid to use in the LAYOUTGET earlier, when we're searching for a usable layout segment. This way we can do it all while holding the i_lock the first time, and ensure that we serialize any LAYOUTGET call that uses a non-layout stateid. This also means a rework of how LAYOUTGET replies are handled, as we must now get the latest stateid if we want to retransmit in response to a retryable error. Most of those errors boil down to the fact that the layout state has changed in some fashion. Thus, what we really want to do is to re-search for a layout when it fails with a retryable error, so that we can avoid reissuing the RPC at all if possible. While the LAYOUTGET RPC is async, the initiating thread always waits for it to complete, so it's effectively synchronous anyway. Currently, when we need to retry a LAYOUTGET because of an error, we drive that retry via the rpc state machine. This means that once the call has been submitted, it runs until it completes. So, we must move the error handling for this RPC out of the rpc_call_done operation and into the caller. In order to handle errors like NFS4ERR_DELAY properly, we must also pass a pointer to the sliding timeout, which is now moved to the stack in pnfs_update_layout. The complicating errors are -NFS4ERR_RECALLCONFLICT and -NFS4ERR_LAYOUTTRYLATER, as those involve a timeout after which we give up and return NULL back to the caller. So, there is some special handling for those errors to ensure that the layers driving the retries can handle that appropriately. Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-17pnfs: only tear down lsegs that precede seqid in LAYOUTRETURN argsJeff Layton1-2/+4
LAYOUTRETURN is "special" in that servers and clients are expected to work with old stateids. When the client sends a LAYOUTRETURN with an old stateid in it then the server is expected to only tear down layout segments that were present when that seqid was current. Ensure that the client handles its accounting accordingly. Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-17pnfs: keep track of the return sequence number in pnfs_layout_hdrJeff Layton1-0/+1
When we want to selectively do a LAYOUTRETURN, we need to specify a stateid that represents most recent layout acquisition that is to be returned. When we mark a layout stateid to be returned, we update the return sequence number in the layout header with that value, if it's newer than the existing one. Then, when we go to do a LAYOUTRETURN on layout header put, we overwrite the seqid in the stateid with the saved one, and then zero it out. Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-17pnfs: record sequence in pnfs_layout_segment when it's createdJeff Layton1-0/+1
In later patches, we're going to teach the client to be more selective about how it returns layouts. This means keeping a record of what the stateid's seqid was at the time that the server handed out a layout segment. Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-05-09pnfs: set NFS_IOHDR_REDO in pnfs_read_resend_pnfsWeston Andros Adamson1-1/+1
Like other resend paths, mark the (old) hdr as NFS_IOHDR_REDO. This ensures the hdr completion function will not count the (old) hdr as good bytes. Also, vector the error back through the hdr->task.tk_status like other retry calls. This fixes a bug with the FlexFiles layout where libaio was reporting more bytes read than requested. Signed-off-by: Weston Andros Adamson <dros@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2016-01-28NFS: Cleanup - rename NFS_LAYOUT_RETURN_BEFORE_CLOSETrond Myklebust1-2/+2
NFS_LAYOUT_RETURN_BEFORE_CLOSE is being used to signal that a layoutreturn is needed, either due to a layout recall or to a layout error. Rename it to NFS_LAYOUT_RETURN_REQUESTED in order to clarify its purpose. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-01-04Merge branch 'pnfs_generic'Trond Myklebust1-2/+31
* pnfs_generic: NFSv4.1/pNFS: Cleanup constify struct pnfs_layout_range arguments NFSv4.1/pnfs: Cleanup copying of pnfs_layout_range structures NFSv4.1/pNFS: Cleanup pnfs_mark_matching_lsegs_invalid() NFSv4.1/pNFS: Fix a race in initiate_file_draining() NFSv4.1/pNFS: pnfs_error_mark_layout_for_return() must always return layout NFSv4.1/pNFS: pnfs_mark_matching_lsegs_return() should set the iomode NFSv4.1/pNFS: Use nfs4_stateid_copy for copying stateids NFSv4.1/pNFS: Don't pass stateids by value to pnfs_send_layoutreturn() NFS: Relax requirements in nfs_flush_incompatible NFSv4.1/pNFS: Don't queue up a new commit if the layout segment is invalid NFS: Allow multiple commit requests in flight per file NFS/pNFS: Fix up pNFS write reschedule layering violations and bugs NFSv4: List stateid information in the callback tracepoints NFSv4.1/pNFS: Don't return NFS4ERR_DELAY unnecessarily in CB_LAYOUTRECALL NFSv4.1/pNFS: Ensure we enforce RFC5661 Section 12.5.5.2.1 pNFS: If we have to delay the layout callback, mark the layout for return NFSv4.1/pNFS: Add a helper to mark the layout as returned pNFS: Ensure nfs4_layoutget_prepare returns the correct error
2016-01-04NFSv4.1/pNFS: Cleanup constify struct pnfs_layout_range argumentsTrond Myklebust1-3/+3
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-01-04NFSv4.1/pnfs: Cleanup copying of pnfs_layout_range structuresTrond Myklebust1-0/+7
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-01-04NFSv4.1/pNFS: pnfs_error_mark_layout_for_return() must always return layoutTrond Myklebust1-1/+1
Fix a bug whereby if all the layout segments could be immediately freed, the call to pnfs_error_mark_layout_for_return() would never result in a layoutreturn. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-12-31NFSv4.1/pNFS: Don't queue up a new commit if the layout segment is invalidTrond Myklebust1-0/+6
If the layout segment is invalid, then we should not be adding more write requests to the commit list. Instead, those writes should be replayed after requesting a new layout. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-12-28pNFS: If we have to delay the layout callback, mark the layout for returnTrond Myklebust1-0/+3
If the client needs to delay the layout callback, then speed up the recall process by marking the remaining layout segments to be actively returned by the client. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-12-28NFSv4.1/pNFS: Add a helper to mark the layout as returnedTrond Myklebust1-0/+13
This ensures that we don't reuse the stateid if a layout return or implied layout return means that we've returned all layout segments Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-12-28pNFS/flexfiles: Don't prevent flexfiles client from retrying LAYOUTGETTrond Myklebust1-21/+0
Fix a bug in which flexfiles clients are falling back to I/O through the MDS even when the FF_FLAGS_NO_IO_THRU_MDS flag is set. The flexfiles client will always report errors through the LAYOUTRETURN and/or LAYOUTERROR mechanisms, so it should normally be safe for it to retry the LAYOUTGET until it fails or succeeds. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-09-23NFS41: make close wait for layoutreturnPeng Tao1-0/+7
If we send a layoutreturn asynchronously before close, the close might reach server first and layoutreturn would fail with BADSTATEID because there is nothing keeping the layout stateid alive. Also do not pretend sending layoutreturn if we are not. Signed-off-by: Peng Tao <tao.peng@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-08-26NFSv4.1/flexfiles: Allow coalescing of new layout segments and existing onesTrond Myklebust1-0/+16
In order to ensure atomicity of updates, we merge the old layout segments into the new ones, and then invalidate the old ones. Also ensure that we order the list of layout segments so that RO segments are preferred over RW. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-08-26NFSv4.1/pnfs: Allow pNFS device drivers to customise layout segment insertionTrond Myklebust1-0/+11
This is needed in order to allow merging of contiguous layout segments, and also to correct the ordering of layouts for those device drivers that don't necessarily want to place the read-write layouts first. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-08-25NFSv4.1/pnfs Improve the packing of struct pnfs_layout_hdrTrond Myklebust1-3/+3
Eliminate a couple of holes in the structure, and move the 2 atomics into the same cacheline. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-08-25NFSv4.2/pnfs: Make the layoutstats timer configurableTrond Myklebust1-0/+3
Allow advanced users to set the layoutstats timer in order to lengthen or shorten the period between layoutstat transmissions to the server. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-08-25NFS41: remove NFS_LAYOUT_ROC flagPeng Tao1-1/+0
If we return delegation before closing, we fail to do roc check during close because NFS_LAYOUT_ROC is cleared by delegreturn and it causes layouts to be still hanging around after delegreturn + close, which is a voilation against protocol. Signed-off-by: Peng Tao <tao.peng@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-08-19NFSv4.1/pnfs: Fix a close/delegreturn hang when return-on-close is setTrond Myklebust1-4/+3
The helper pnfs_roc() has already verified that we have no delegations, and no further open files, hence no outstanding I/O and it has marked all the return-on-close lsegs as being invalid. Furthermore, it sets the NFS_LAYOUT_RETURN bit, thus serialising the close/delegreturn with all future layoutget calls on this inode. The checks in pnfs_roc_drain() for valid layout segments are therefore redundant: those cannot exist until another layoutget completes. The other check for whether or not NFS_LAYOUT_RETURN is set, actually causes a hang, since we already know that we hold that flag. To fix, we therefore strip out all the functionality in pnfs_roc_drain() except the retrieval of the barrier state, and then rename the function accordingly. Reported-by: Christoph Hellwig <hch@infradead.org> Fixes: 5c4a79fb2b1c ("Don't prevent layoutgets when doing return-on-close") Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-08-12NFSv4.2/pnfs: Use GFP_NOIO for layoutstat reporting in the writeback pathTrond Myklebust1-2/+2
Prevent a potential deadlock. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-06-26nfs: provide pnfs_report_layoutstat when NFS42 is disabledPeng Tao1-2/+10
kbuild test robot reported: fs/built-in.o: In function `pnfs_report_layoutstat': >> (.text+0x151a1c): undefined reference to `nfs42_proc_layoutstats_generic' Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Peng Tao <tao.peng@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-06-24pnfs: add pnfs_report_layoutstat helper functionPeng Tao1-0/+3
Reviewed-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Peng Tao <tao.peng@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-04-27Merge tag 'nfs-for-4.1-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfsLinus Torvalds1-2/+22
Pull NFS client updates from Trond Myklebust: "Another set of mainly bugfixes and a couple of cleanups. No new functionality in this round. Highlights include: Stable patches: - Fix a regression in /proc/self/mountstats - Fix the pNFS flexfiles O_DIRECT support - Fix high load average due to callback thread sleeping Bugfixes: - Various patches to fix the pNFS layoutcommit support - Do not cache pNFS deviceids unless server notifications are enabled - Fix a SUNRPC transport reconnection regression - make debugfs file creation failure non-fatal in SUNRPC - Another fix for circular directory warnings on NFSv4 "junctioned" mountpoints - Fix locking around NFSv4.2 fallocate() support - Truncating NFSv4 file opens should also sync O_DIRECT writes - Prevent infinite loop in rpcrdma_ep_create() Features: - Various improvements to the RDMA transport code's handling of memory registration - Various code cleanups" * tag 'nfs-for-4.1-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (55 commits) fs/nfs: fix new compiler warning about boolean in switch nfs: Remove unneeded casts in nfs NFS: Don't attempt to decode missing directory entries Revert "nfs: replace nfs_add_stats with nfs_inc_stats when add one" NFS: Rename idmap.c to nfs4idmap.c NFS: Move nfs_idmap.h into fs/nfs/ NFS: Remove CONFIG_NFS_V4 checks from nfs_idmap.h NFS: Add a stub for GETDEVICELIST nfs: remove WARN_ON_ONCE from nfs_direct_good_bytes nfs: fix DIO good bytes calculation nfs: Fetch MOUNTED_ON_FILEID when updating an inode sunrpc: make debugfs file creation failure non-fatal nfs: fix high load average due to callback thread sleeping NFS: Reduce time spent holding the i_mutex during fallocate() NFS: Don't zap caches on fallocate() xprtrdma: Make rpcrdma_{un}map_one() into inline functions xprtrdma: Handle non-SEND completions via a callout xprtrdma: Add "open" memreg op xprtrdma: Add "destroy MRs" memreg op xprtrdma: Add "reset MRs" memreg op ...
2015-04-15VFS: normal filesystems (and lustre): d_inode() annotationsDavid Howells1-2/+2
that's the bulk of filesystem drivers dealing with inodes of their own Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-03-27NFSv4.1/pnfs: Separate out metadata and data consistency for pNFSTrond Myklebust1-0/+18
The LAYOUTCOMMIT operation means different things to different layout types. For blocks and objects, it is both a data and metadata consistency operation. For files and flexfiles, it is only a metadata consistency operation. This patch separates out the 2 cases, allowing the files/flexfiles layout drivers to optimise away the data consistency calls to layoutcommit. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-03-27NFSv4.1/pnfs: Refactor pnfs_set_layoutcommit()Trond Myklebust1-2/+1
pnfs_set_layoutcommit() and pnfs_commit_set_layoutcommit() are 100% identical except for the function arguments. Refactor to eliminate the difference. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-03-27NFSv4.1: Don't cache deviceids that have no notificationsTrond Myklebust1-0/+2
The spec says that once all layouts that reference a given deviceid have been returned, then we are only allowed to continue to cache the deviceid if the metadata server supports notifications. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-03-27NFSv4.1: Convert pNFS deviceid to use kfree_rcu()Trond Myklebust1-0/+1
Use of synchronize_rcu() when unmounting and potentially freeing a lot of deviceids is problematic. There really is no reason why we can't just use kfree_rcu() here. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-02-18pnfs: Refactor the *_layout_mark_request_commit to use ↵Tom Haynes1-0/+4
pnfs_layout_mark_request_commit The File Layout's filelayout_mark_request_commit() is almost the Flex File Layout's ff_layout_mark_request_commit(). And that can be reduced by calling into nfs_request_add_commit_list(). Signed-off-by: Tom Haynes <loghyr@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-02-04Merge branch 'flexfiles'Trond Myklebust1-20/+105
* flexfiles: (53 commits) pnfs: lookup new lseg at lseg boundary nfs41: .init_read and .init_write can be called with valid pg_lseg pnfs: Update documentation on the Layout Drivers pnfs/flexfiles: Add the FlexFile Layout Driver nfs: count DIO good bytes correctly with mirroring nfs41: wait for LAYOUTRETURN before retrying LAYOUTGET nfs: add a helper to set NFS_ODIRECT_RESCHED_WRITES to direct writes nfs41: add NFS_LAYOUT_RETRY_LAYOUTGET to layout header flags nfs/flexfiles: send layoutreturn before freeing lseg nfs41: introduce NFS_LAYOUT_RETURN_BEFORE_CLOSE nfs41: allow async version layoutreturn nfs41: add range to layoutreturn args pnfs: allow LD to ask to resend read through pnfs nfs: add nfs_pgio_current_mirror helper nfs: only reset desc->pg_mirror_idx when mirroring is supported nfs41: add a debug warning if we destroy an unempty layout pnfs: fail comparison when bucket verifier not set nfs: mirroring support for direct io nfs: add mirroring support to pgio layer pnfs: pass ds_commit_idx through the commit path ... Conflicts: fs/nfs/pnfs.c fs/nfs/pnfs.h
2015-02-03pnfs/flexfiles: Add the FlexFile Layout DriverTom Haynes1-0/+1
The flexfile layout is a new layout that extends the file layout. It is currently being drafted as a specification at https://datatracker.ietf.org/doc/draft-ietf-nfsv4-layout-types/ Signed-off-by: Weston Andros Adamson <dros@primarydata.com> Signed-off-by: Tom Haynes <loghyr@primarydata.com> Signed-off-by: Tao Peng <bergwolf@primarydata.com>
2015-02-03nfs41: wait for LAYOUTRETURN before retrying LAYOUTGETPeng Tao1-1/+4
Also take care to stop waiting if someone clears retry bit. Signed-off-by: Peng Tao <tao.peng@primarydata.com>
2015-02-03nfs41: add NFS_LAYOUT_RETRY_LAYOUTGET to layout header flagsPeng Tao1-0/+18
Use it to indicate that LD wants to retry layoutget. LD can set it whenever it wants the common pnfs code to return and retry pnfs path through a new layout. The bit gets cleared when client does a new layoutget, when client closes the file (ROC case), or when kernel needs to evict the inode (non-ROC case). Signed-off-by: Peng Tao <tao.peng@primarydata.com>
2015-02-03nfs41: introduce NFS_LAYOUT_RETURN_BEFORE_CLOSEPeng Tao1-0/+1
When it is set, generic pnfs would try to send layoutreturn right before last close/delegation_return regard less NFS_LAYOUT_ROC is set or not. LD can then make sure layoutreturn is always sent rather than being omitted. The difference against NFS_LAYOUT_RETURN is that NFS_LAYOUT_RETURN_BEFORE_CLOSE does not block usage of the layout so LD can set it and expect generic layer to try pnfs path at the same time. Signed-off-by: Peng Tao <tao.peng@primarydata.com> Signed-off-by: Tom Haynes <loghyr@primarydata.com>
2015-02-03nfs41: allow async version layoutreturnPeng Tao1-1/+1
Signed-off-by: Peng Tao <tao.peng@primarydata.com> Signed-off-by: Tom Haynes <loghyr@primarydata.com>
2015-02-03pnfs: allow LD to ask to resend read through pnfsPeng Tao1-0/+2
If current IO cannot be completed due to some transient errors, LD may want to ask generic layer to resend the request through pnfs again. Signed-off-by: Peng Tao <tao.peng@primarydata.com> Signed-off-by: Tom Haynes <loghyr@primarydata.com>
2015-02-03pnfs: pass ds_commit_idx through the commit pathWeston Andros Adamson1-4/+5
Pass ds_commit_idx through the nfs commit path. It's used to select the commit bucket when using pnfs and is ignored when not using pnfs. Several functions had to be changed: nfs_retry_commit, nfs_mark_request_commit, pnfs_mark_request_commit and the pnfs layout driver .mark_request_commit functions. Signed-off-by: Tom Haynes <loghyr@primarydata.com>
2015-02-03pnfs: release lseg in pnfs_generic_pg_cleanupWeston Andros Adamson1-0/+1
This is needed to support mirrored writes - the first write can't just trash the lseg, we need to keep it around until all mirrors have written. Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
2015-02-03nfs41: don't use a layout if it is marked for returningPeng Tao1-0/+1
And if we are to return the same type of layouts, don't bother sending more layoutgets. Signed-off-by: Peng Tao <tao.peng@primarydata.com> Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
2015-02-03nfs41: add a helper to mark layout for returnPeng Tao1-0/+4
It marks all matching layout segments as NFS_LSEG_LAYOUTRETURN, which is an indicator for pnfs_put_lseg() to send layoutreturn, and also prevents pnfs_update_layout() from using the returning segments. Once it is set, it never gets cleared. It also sets proper io failure bit so that pnfs path can be retried after PNFS_LAYOUTGET_RETRY_TIMEOUT second. Signed-off-by: Peng Tao <tao.peng@primarydata.com> Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
2015-02-03nfs41: serialize first layoutget of a filePeng Tao1-0/+1
Per RFC 5661 Errata 3208: | A client MAY always forget its layout state and associated | layout stateid at any time (See also section 12.5.5.1). | In such case, the client MUST use a non-layout stateid for the next | LAYOUTGET operation. This will signal the server that the client has | no more layouts on the file and its respective layout state can be | released before issuing a new layout in response to LAYOUTGET. In order to make such a signal unique to server, client needs to serialize all layoutgets using non-layout stateid. We implement this by serializing layoutgets when client has no layout segments at hand. Signed-off-by: Peng Tao <tao.peng@primarydata.com> Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>