To do asynchronous copies, NFSD creates a new kthread to handle the request. Upon receiving the COPY, it generates a unique copy stateid (stored in a global list for keeping track of state for OFFLOAD_STATUS to be queried by), starts the thread, and replies back to the client. nfsd4_copy arguments that are allocated on the stack are copies for the kthread. In the async copy handler, it calls into VFS copy_file_range() (for synch we keep the 4MB chunk and requested size for the async copy). If error is encountered it's saved but also we save the amount of data copied so far. Once done, the results are queued for the callback workqueue and sent via CB_OFFLOAD. When the server received an OFFLOAD_CANCEL, it will find the kthread running the copy and will send a SIGPENDING and kthread_stop() and it will interrupt the ongoing do_splice() and once vfs returns we are choosing not to send the CB_OFFLOAD back to the client. When the server receives an OFFLOAD_STATUS, it will find the kthread running the copy and will query the i_size_read() of the associated filehandle of the destination file and return the result. v5: 1. reimplementing asynchronous copy to use kthreads instead of the workqueue 2. store asynchronous copies in the list of the nfs4_client structure 3. when copying nfsd4_copy datastructure for the async copy refcount the nfs4_client structure as well as struct file src/dst structure 4. add refcount to the nfsd4_copy structure to coordinate with offload_status and offload_cancel 5. offload_cancel/copy_shutdown sets the SIGPENDING in the copy's thread to interrupt do_splice and calls kthread_stop to wait for the copy to stop 6. offload_cancel adds MODIFIES_SOMETHING to flags 7. offload_status reports the size of the destination file form i_size_read() instead of before 4MB loop updated chunk size. 8. for async copy call vfs_copy_file_range() with the whole copy size. still keep the loop to do more the MAX_RW_COUNT that do_splice can do. Olga Kornievskaia (10): NFSD CB_OFFLOAD xdr NFSD OFFLOAD_STATUS xdr NFSD OFFLOAD_CANCEL xdr NFSD xdr callback stateid in async COPY reply NFSD first draft of async copy NFSD return nfs4_stid in nfs4_preprocess_stateid_op NFSD create new stateid for async copy NFSD handle OFFLOAD_CANCEL op NFSD support OFFLOAD_STATUS NFSD stop queued async copies on client shutdown fs/nfsd/netns.h | 8 ++ fs/nfsd/nfs4callback.c | 97 +++++++++++++++ fs/nfsd/nfs4proc.c | 321 ++++++++++++++++++++++++++++++++++++++++++++----- fs/nfsd/nfs4state.c | 77 +++++++++++- fs/nfsd/nfs4xdr.c | 50 ++++++-- fs/nfsd/nfsctl.c | 1 + fs/nfsd/state.h | 21 +++- fs/nfsd/xdr4.h | 28 +++++ fs/nfsd/xdr4cb.h | 10 ++ 9 files changed, 576 insertions(+), 37 deletions(-) -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
