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* nfsd: pNFS block layout driverChristoph Hellwig2015-02-051-0/+8
| | | | | | | | | | | | Add a small shim between core nfsd and filesystems to translate the somewhat cumbersome pNFS data structures and semantics to something more palatable for Linux filesystems. Thanks to Rick McNeal for the old prototype pNFS blocklayout server code, which gave a lot of inspiration to this version even if no code is left from it. Signed-off-by: Christoph Hellwig <hch@lst.de>
* nfsd: add trace eventsChristoph Hellwig2015-02-021-1/+15
| | | | | | | | For now just a few simple events to trace the layout stateid lifetime, but these already were enough to find several bugs in the Linux client layout stateid handling. Signed-off-by: Christoph Hellwig <hch@lst.de>
* nfsd: implement pNFS layout recallsChristoph Hellwig2015-02-021-1/+213
| | | | | | | | | | | | | | | | | | | | Add support to issue layout recalls to clients. For now we only support full-file recalls to get a simple and stable implementation. This allows to embedd a nfsd4_callback structure in the layout_state and thus avoid any memory allocations under spinlocks during a recall. For normal use cases that do not intent to share a single file between multiple clients this implementation is fully sufficient. To ensure layouts are recalled on local filesystem access each layout state registers a new FL_LAYOUT lease with the kernel file locking code, which filesystems that support pNFS exports that require recalls need to break on conflicting access patterns. The XDR code is based on the old pNFS server implementation by Andy Adamson, Benny Halevy, Boaz Harrosh, Dean Hildebrand, Fred Isaman, Marc Eshel, Mike Sager and Ricardo Labiaga. Signed-off-by: Christoph Hellwig <hch@lst.de>
* nfsd: implement pNFS operationsChristoph Hellwig2015-02-021-0/+487
Add support for the GETDEVICEINFO, LAYOUTGET, LAYOUTCOMMIT and LAYOUTRETURN NFSv4.1 operations, as well as backing code to manage outstanding layouts and devices. Layout management is very straight forward, with a nfs4_layout_stateid structure that extends nfs4_stid to manage layout stateids as the top-level structure. It is linked into the nfs4_file and nfs4_client structures like the other stateids, and contains a linked list of layouts that hang of the stateid. The actual layout operations are implemented in layout drivers that are not part of this commit, but will be added later. The worst part of this commit is the management of the pNFS device IDs, which suffers from a specification that is not sanely implementable due to the fact that the device-IDs are global and not bound to an export, and have a small enough size so that we can't store the fsid portion of a file handle, and must never be reused. As we still do need perform all export authentication and validation checks on a device ID passed to GETDEVICEINFO we are caught between a rock and a hard place. To work around this issue we add a new hash that maps from a 64-bit integer to a fsid so that we can look up the export to authenticate against it, a 32-bit integer as a generation that we can bump when changing the device, and a currently unused 32-bit integer that could be used in the future to handle more than a single device per export. Entries in this hash table are never deleted as we can't reuse the ids anyway, and would have a severe lifetime problem anyway as Linux export structures are temporary structures that can go away under load. Parts of the XDR data, structures and marshaling/unmarshaling code, as well as many concepts are derived from the old pNFS server implementation from Andy Adamson, Benny Halevy, Dean Hildebrand, Marc Eshel, Fred Isaman, Mike Sager, Ricardo Labiaga and many others. Signed-off-by: Christoph Hellwig <hch@lst.de>
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