On Fri, Oct 13, 2017 at 5:26 PM, J. Bruce Fields <bfields@xxxxxxxxxx> wrote: > On Fri, Oct 13, 2017 at 04:54:02PM -0400, Olga Kornievskaia wrote: >> 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. > > That assumes we're copying into a previously empty file? Sigh. Alright, then it's back to my original solution where I broke everything into 4MB calls and kept track of bytes copies so far. > > --b. > >> >> 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 -- 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
