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* NFSv4: Report the error from nfs4_select_rw_stateid()Trond Myklebust2019-08-051-6/+1Star
| | | | | | | | In pnfs_update_layout() ensure that we do report any fatal errors from nfs4_select_rw_stateid(). Fixes: d9aba2b40de6 ("NFSv4: Don't use the zero stateid with layoutget") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs/flexfiles: Add tracepoints for detecting pnfs fallback to MDSTrond Myklebust2019-07-181-0/+2
| | | | | | | Add tracepoints to allow debugging of the event chain leading to a pnfs fallback to doing I/O through the MDS. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs: Fix a problem where we gratuitously start doing I/O through the MDSTrond Myklebust2019-07-181-1/+1
| | | | | | | | | | If the client has to stop in pnfs_update_layout() to wait for another layoutget to complete, it currently exits and defaults to I/O through the MDS if the layoutget was successful. Fixes: d03360aaf5cc ("pNFS: Ensure we return the error if someone kills...") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: stable@vger.kernel.org # v4.20+
* NFSv4: Don't use the zero stateid with layoutgetTrond Myklebust2019-07-181-3/+11
| | | | | | | | | The NFSv4.1 protocol explicitly forbids us from using the zero stateid together with layoutget, so when we see that nfs4_select_rw_stateid() is unable to return a valid delegation, lock or open stateid, then we should initiate recovery and retry. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* NFS: Clean up writeback codeTrond Myklebust2019-07-061-1/+1
| | | | | | | | Now that the VM promises never to recurse back into the filesystem layer on writeback, remove all the GFP_NOFS references etc from the generic writeback code. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* NFS: Add a helper to return a pointer to the open context of a struct nfs_pageTrond Myklebust2019-04-251-2/+2
| | | | | | | | Add a helper for when we remove the explicit pointer to the open context. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* pNFS: Fix a typo in pnfs_update_layoutTrond Myklebust2019-03-121-1/+1
| | | | | | | | | We're supposed to wait for the outstanding layout count to go to zero, but that got lost somehow. Fixes: d03360aaf5cca ("pNFS: Ensure we return the error if someone...") Reported-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* NFS/pnfs: Bulk destroy of layouts needs to be safe w.r.t. umountTrond Myklebust2019-02-231-10/+23
| | | | | | | | | If a bulk layout recall or a metadata server reboot coincides with a umount, then holding a reference to an inode is unsafe unless we also hold a reference to the super block. Fixes: fd9a8d7160937 ("NFSv4.1: Fix bulk recall and destroy of layouts") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* NFS/NFSD/SUNRPC: replace generic creds with 'struct cred'.NeilBrown2018-12-191-7/+7
| | | | | | | | | | | | | | | | | | | | | | SUNRPC has two sorts of credentials, both of which appear as "struct rpc_cred". There are "generic credentials" which are supplied by clients such as NFS and passed in 'struct rpc_message' to indicate which user should be used to authorize the request, and there are low-level credentials such as AUTH_NULL, AUTH_UNIX, AUTH_GSS which describe the credential to be sent over the wires. This patch replaces all the generic credentials by 'struct cred' pointers - the credential structure used throughout Linux. For machine credentials, there is a special 'struct cred *' pointer which is statically allocated and recognized where needed as having a special meaning. A look-up of a low-level cred will map this to a machine credential. Signed-off-by: NeilBrown <neilb@suse.com> Acked-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* NFS: Convert lookups of the open context to RCUTrond Myklebust2018-09-301-1/+4
| | | | | | | Reduce contention on the inode->i_lock by ensuring that we use RCU when looking up the NFS open context. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pNFS: Don't allocate more pages than we need to fit a layoutget responseTrond Myklebust2018-09-301-0/+7
| | | | | | | | For the 'files' and 'flexfiles' layout types, we do not expect the reply to be any larger than 4k. The block and scsi layout types are a little more greedy, so we keep allocating the maximum response size for now. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pNFS: Don't zero out the array in nfs4_alloc_pages()Trond Myklebust2018-09-301-2/+2
| | | | | | We don't need a zeroed out array, since it is immediately being filled. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pNFS: Ensure we return the error if someone kills a waiting layoutgetTrond Myklebust2018-09-141-10/+16
| | | | | | | | If someone interrupts a wait on one or more outstanding layoutgets in pnfs_update_layout() then return the ERESTARTSYS/EINTR error. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* pNFS: Remove unwanted optimisation of layoutgetTrond Myklebust2018-08-211-6/+0Star
| | | | | | | | | | If we knew that the file was empty, we wouldn't be asking for a layout. Any optimisation here is already done before calling pnfs_update_layout(). As it stands, we sometimes end up doing an unnecessary inband read to the MDS even when holding a layout. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* pNFS: Treat RECALLCONFLICT like DELAY...Trond Myklebust2018-08-161-9/+0Star
| | | | | | | | Yes, it is possible to get trapped in a loop, but the server should be administratively revoking the recalled layout if it never gets returned. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* pNFS: When updating the stateid in layoutreturn, also update the recall rangeTrond Myklebust2018-08-161-1/+4
| | | | | | | | | | When we update the layout stateid in nfs4_layoutreturn_refresh_stateid, we should also update the range in order to let the server know we're actually returning everything. Fixes: 16c278dbfa63 ("pnfs: Fix handling of NFS4ERR_OLD_STATEID replies...") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* pnfs: Use true and false for boolean valuesGustavo A. R. Silva2018-08-081-1/+1
| | | | | | | | | | Return statements in functions returning bool should use true or false instead of an integer value. This issue was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* pnfs: pnfs_find_lseg() should not check NFS_LSEG_LAYOUTRETURNTrond Myklebust2018-08-081-1/+0Star
| | | | | | | | | | | Layout segment validity is determined only by the NFS_LSEG_VALID flag. If it is set, the layout segment is finable. As it is, when the flexfiles driver sets NFS_LSEG_LAYOUTRETURN to indicate that we cannot discard the layout segment, but that it must be returned, then this can result in an unnecessary layoutget storm. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* pnfs: Fix handling of NFS4ERR_OLD_STATEID replies to layoutreturnTrond Myklebust2018-08-081-3/+14
| | | | | | | | | If the server tells us that out layoutreturn raced with another layout update, then we must ensure that the new layout segments are not in use before we resend with an updated layout stateid. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* pNFS: Parse the results of layoutget on open even if permissions checks failTrond Myklebust2018-07-261-4/+0Star
| | | | | | | | | | | | Even if the results of the permissions checks failed, we should parse the results of the layout on open call so that we can return the layout if required. Note that we also want to ignore the sequence counter for whether or not a layout recall occurred. If the recall pertained to our OPEN, then the callback will know, and will attempt to wait for us to finih processing anyway. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pNFS: Wait for stale layoutget calls to complete in pnfs_update_layout()Trond Myklebust2018-07-261-5/+31
| | | | | | | | If the old layout was recalled, and we returned NFS4ERR_NOMATCHINGLAYOUT then we need to wait for all outstanding layoutget calls to complete before we can send a new one. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pNFS: Ignore non-recalled layouts in pnfs_layout_need_return()Trond Myklebust2018-07-261-1/+10
| | | | | | | If a layout has been recalled, then we should fire off a layoutreturn as soon as all the layout segments that match the recall have been retired. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pNFS: Don't discard layout segments that are marked for returnTrond Myklebust2018-07-261-7/+27
| | | | | | | | | If there are layout segments that are marked for return, then we need to ensure that pnfs_mark_matching_lsegs_return() does not just silently discard them, but it should tell the caller that there is a layoutreturn scheduled. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* skip LAYOUTRETURN if layout is invalidOlga Kornievskaia2018-06-121-2/+4
| | | | | | | | | | | | | | | Currently, when IO to DS fails, client returns the layout and retries against the MDS. However, then on umounting (inode eviction) it returns the layout again. This is because pnfs_return_layout() was changed in commit d78471d32bb6 ("pnfs/blocklayout: set PNFS_LAYOUTRETURN_ON_ERROR") to always set NFS_LAYOUT_RETURN_REQUESTED so even if we returned the layout, it will be returned again. Instead, let's also check if we have already marked the layout invalid. Signed-off-by: Olga Kornievskaia <kolga@netapp.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs: Don't call commit on failed layoutget-on-openTrond Myklebust2018-05-311-6/+1Star
| | | | | | | If the layoutget on open call failed, we can't really commit the inode, so don't bother calling it. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pNFS: Don't send LAYOUTGET on OPEN for read, if we already have cached dataTrond Myklebust2018-05-311-0/+5
| | | | | | | | If we're only opening the file for reading, and the file is empty and/or we already have cached data, then heuristically optimise away the LAYOUTGET. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* NFSv4/pnfs: Don't switch off layoutget-on-open for transient errorsTrond Myklebust2018-05-311-7/+15
| | | | | | | | | | Ensure that we only switch off the LAYOUTGET operation in the OPEN compound when the server is truly broken, and/or it is complaining that the compound is too large. Currently, we end up turning off the functionality permanently, even for transient errors such as EACCES or ENOSPC. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* NFSv4/pnfs: Ensure pnfs_parse_lgopen() won't try to parse uninitialised dataTrond Myklebust2018-05-311-1/+2
| | | | | | | | | | | | | We need to ensure that pnfs_parse_lgopen() doesn't try to parse a struct nfs4_layoutget_res that was not filled by a successful call to decode_layoutget(). This can happen if we performed a cached open, or if either the OP_ACCESS or OP_GETATTR operations preceding the OP_LAYOUTGET in the compound returned an error. By initialising the 'status' field to NFS4ERR_DELAY, we ensure that pnfs_parse_lgopen() won't try to interpret the structure. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs: Fix manipulation of NFS_LAYOUT_FIRST_LAYOUTGETFred Isaman2018-05-311-6/+14
| | | | | | | The flag was not always being cleared after LAYOUTGET on OPEN. Signed-off-by: Fred Isaman <fred.isaman@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs: Add barrier to prevent lgopen using LAYOUTGET during recallFred Isaman2018-05-311-1/+7
| | | | | | | | | | Since the LAYOUTGET on OPEN can be sent without prior inode information, existing methods to prevent LAYOUTGET from being sent while processing CB_LAYOUTRECALL don't work. Track if a recall occurred while LAYOUTGET was being sent, and if so ignore the results. Signed-off-by: Fred Isaman <fred.isaman@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs: Stop attempting LAYOUTGET on OPEN on failureFred Isaman2018-05-311-1/+18
| | | | | Signed-off-by: Fred Isaman <fred.isaman@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs: Add LAYOUTGET to OPEN of an existing fileFred Isaman2018-05-311-17/+73
| | | | | Signed-off-by: Fred Isaman <fred.isaman@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pNFS: Refactor nfs4_layoutget_release()Trond Myklebust2018-05-311-0/+50
| | | | | | | Move the actual freeing of the struct nfs4_layoutget into fs/nfs/pnfs.c where it can be reused by the layoutget on open code. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs: Add LAYOUTGET to OPEN of a new fileFred Isaman2018-05-311-2/+79
| | | | | | | | This triggers when have no pre-existing inode to attach to. The preexisting case is saved for later. Signed-off-by: Fred Isaman <fred.isaman@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs: Change pnfs_alloc_init_layoutget_args call signatureFred Isaman2018-05-311-12/+28
| | | | | | | | | | Don't send in a layout, instead use the (possibly NULL) inode. This is needed for LAYOUTGET attached to an OPEN where the inode is not yet set. Signed-off-by: Fred Isaman <fred.isaman@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs: Move nfs4_opendata into nfs4_fs.hFred Isaman2018-05-311-0/+1
| | | | | | | It will be needed now by the pnfs code. Signed-off-by: Fred Isaman <fred.isaman@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs: move allocations out of nfs4_proc_layoutgetFred Isaman2018-05-311-1/+11
| | | | | | | They work better in the new alloc_init function. Signed-off-by: Fred Isaman <fred.isaman@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pnfs: refactor send_layoutgetFred Isaman2018-05-311-18/+15Star
| | | | | | | Pull out the alloc/init part for eventual reuse by OPEN. Signed-off-by: Fred Isaman <fred.isaman@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
* pNFS: Prevent the layout header refcount going to zero in pnfs_roc()Trond Myklebust2018-03-081-3/+10
| | | | | | | | | | | Ensure that we hold a reference to the layout header when processing the pNFS return-on-close so that the refcount value does not inadvertently go to zero. Reported-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Cc: stable@vger.kernel.org # v4.10+ Tested-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
* nfs/pnfs: fix nfs_direct_req ref leak when i/o falls back to the mdsScott Mayhew2018-01-151-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently when falling back to doing I/O through the MDS (via pnfs_{read|write}_through_mds), the client frees the nfs_pgio_header without releasing the reference taken on the dreq via pnfs_generic_pg_{read|write}pages -> nfs_pgheader_init -> nfs_direct_pgio_init. It then takes another reference on the dreq via nfs_generic_pg_pgios -> nfs_pgheader_init -> nfs_direct_pgio_init and as a result the requester will become stuck in inode_dio_wait. Once that happens, other processes accessing the inode will become stuck as well. Ensure that pnfs_read_through_mds() and pnfs_write_through_mds() clean up correctly by calling hdr->completion_ops->completion() instead of calling hdr->release() directly. This can be reproduced (sometimes) by performing "storage failover takeover" commands on NetApp filer while doing direct I/O from a client. This can also be reproduced using SystemTap to simulate a failure while doing direct I/O from a client (from Dave Wysochanski <dwysocha@redhat.com>): stap -v -g -e 'probe module("nfs_layout_nfsv41_files").function("nfs4_fl_prepare_ds").return { $return=NULL; exit(); }' Suggested-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Scott Mayhew <smayhew@redhat.com> Fixes: 1ca018d28d ("pNFS: Fix a memory leak when attempted pnfs fails") Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
* pnfs/blocklayout: handle transient devicesBenjamin Coddington2018-01-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | PNFS block/SCSI layouts should gracefully handle cases where block devices are not available when a layout is retrieved, or the block devices are removed while the client holds a layout. While setting up a layout segment, keep a record of an unavailable or un-parsable block device in cache with a flag so that subsequent layouts do not spam the server with GETDEVINFO. We can reuse the current NFS_DEVICEID_UNAVAILABLE handling with one variation: instead of reusing the device, we will discard it and send a fresh GETDEVINFO after the timeout, since the lookup and validation of the device occurs within the GETDEVINFO response handling. A lookup of a layout segment that references an unavailable device will return a segment with the NFS_LSEG_UNAVAILABLE flag set. This will allow the pgio layer to mark the layout with the appropriate fail bit, which forces subsequent IO to the MDS, and prevents spamming the server with LAYOUTGET, LAYOUTRETURN. Finally, when IO to a block device fails, look up the block device(s) referenced by the pgio header, and mark them as unavailable. Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
* pNFS: Retry NFS4ERR_OLD_STATEID errors in layoutreturn-on-closeTrond Myklebust2017-11-171-0/+18
| | | | | | | | | If our layoutreturn on close operation returns an NFS4ERR_OLD_STATEID, then try to update the stateid and retry. We know that there should be no further LAYOUTGET requests being launched. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* NFS: Fix bool initialization/comparisonThomas Meyer2017-11-171-1/+1
| | | | | | | | Bool initializations should use true and false. Bool tests don't need comparisons. Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* fs, nfs: convert pnfs_layout_hdr.plh_refcount from atomic_t to refcount_tElena Reshetova2017-11-171-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable pnfs_layout_hdr.plh_refcount is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook <keescook@chromium.org> Reviewed-by: David Windsor <dwindsor@gmail.com> Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* fs, nfs: convert pnfs_layout_segment.pls_refcount from atomic_t to refcount_tElena Reshetova2017-11-171-6/+6
| | | | | | | | | | | | | | refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
* pNFS: Use the standard I/O stateid when calling LAYOUTGETTrond Myklebust2017-09-121-5/+9
| | | | | | | | | | Instead of having a private method for copying the open/delegation stateid, use the same call that is used for standard I/O through the MDS. Note that this means we transmit the stateid with a zero seqid, avoiding issues with NFS4ERR_OLD_STATEID. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
* NFS: Fix 2 use after free issues in the I/O codeTrond Myklebust2017-09-091-2/+0Star
| | | | | | | | | | | | | | | The writeback code wants to send a commit after processing the pages, which is why we want to delay releasing the struct path until after that's done. Also, the layout code expects that we do not free the inode before we've put the layout segments in pnfs_writehdr_free() and pnfs_readhdr_free() Fixes: 919e3bd9a875 ("NFS: Ensure we commit after writeback is complete") Fixes: 4714fb51fd03 ("nfs: remove pgio_header refcount, related cleanup") Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
* NFSv4/pnfs: Replace pnfs_put_lseg_locked() with pnfs_put_lseg()Trond Myklebust2017-08-151-41/+0Star
| | | | | | | Now that we no longer hold the inode->i_lock when manipulating the commit lists, it is safe to call pnfs_put_lseg() again. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
* pnfs: Fix the check for requests in range of layout segmentBenjamin Coddington2017-05-241-8/+17
| | | | | | | | | | | | | | | | | | | It's possible and acceptable for NFS to attempt to add requests beyond the range of the current pgio->pg_lseg, a case which should be caught and limited by the pg_test operation. However, the current handling of this case replaces pgio->pg_lseg with a new layout segment (after a WARN) within that pg_test operation. That will cause all the previously added requests to be submitted with this new layout segment, which may not be valid for those requests. Fix this problem by only returning zero for the number of bytes to coalesce from pg_test for this case which allows any previously added requests to complete on the current layout segment. The check for requests starting out of range of the layout segment moves to pg_init, so that the replacement of pgio->pg_lseg will be done when the next request is added. Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
* pNFS: Fix a deadlock when coalescing writes and returning the layoutTrond Myklebust2017-05-021-2/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Consider the following deadlock: Process P1 Process P2 Process P3 ========== ========== ========== lock_page(page) lseg = pnfs_update_layout(inode) lo = NFS_I(inode)->layout pnfs_error_mark_layout_for_return(lo) lock_page(page) lseg = pnfs_update_layout(inode) In this scenario, - P1 has declared the layout to be in error, but P2 holds a reference to a layout segment on that inode, so the layoutreturn is deferred. - P2 is waiting for a page lock held by P3. - P3 is asking for a new layout segment, but is blocked waiting for the layoutreturn. The fix is to ensure that pnfs_error_mark_layout_for_return() does not set the NFS_LAYOUT_RETURN flag, which blocks P3. Instead, we allow the latter to call LAYOUTGET so that it can make progress and unblock P2. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
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