diff options
Diffstat (limited to 'fs/netfs/write_collect.c')
| -rw-r--r-- | fs/netfs/write_collect.c | 809 |
1 files changed, 809 insertions, 0 deletions
diff --git a/fs/netfs/write_collect.c b/fs/netfs/write_collect.c new file mode 100644 index 0000000000..488147439f --- /dev/null +++ b/fs/netfs/write_collect.c @@ -0,0 +1,809 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Network filesystem write subrequest result collection, assessment + * and retrying. + * + * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/export.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/slab.h> +#include "internal.h" + +/* Notes made in the collector */ +#define HIT_PENDING 0x01 /* A front op was still pending */ +#define SOME_EMPTY 0x02 /* One of more streams are empty */ +#define ALL_EMPTY 0x04 /* All streams are empty */ +#define MAYBE_DISCONTIG 0x08 /* A front op may be discontiguous (rounded to PAGE_SIZE) */ +#define NEED_REASSESS 0x10 /* Need to loop round and reassess */ +#define REASSESS_DISCONTIG 0x20 /* Reassess discontiguity if contiguity advances */ +#define MADE_PROGRESS 0x40 /* Made progress cleaning up a stream or the folio set */ +#define BUFFERED 0x80 /* The pagecache needs cleaning up */ +#define NEED_RETRY 0x100 /* A front op requests retrying */ +#define SAW_FAILURE 0x200 /* One stream or hit a permanent failure */ + +/* + * Successful completion of write of a folio to the server and/or cache. Note + * that we are not allowed to lock the folio here on pain of deadlocking with + * truncate. + */ +int netfs_folio_written_back(struct folio *folio) +{ + enum netfs_folio_trace why = netfs_folio_trace_clear; + struct netfs_folio *finfo; + struct netfs_group *group = NULL; + int gcount = 0; + + if ((finfo = netfs_folio_info(folio))) { + /* Streaming writes cannot be redirtied whilst under writeback, + * so discard the streaming record. + */ + folio_detach_private(folio); + group = finfo->netfs_group; + gcount++; + kfree(finfo); + why = netfs_folio_trace_clear_s; + goto end_wb; + } + + if ((group = netfs_folio_group(folio))) { + if (group == NETFS_FOLIO_COPY_TO_CACHE) { + why = netfs_folio_trace_clear_cc; + folio_detach_private(folio); + goto end_wb; + } + + /* Need to detach the group pointer if the page didn't get + * redirtied. If it has been redirtied, then it must be within + * the same group. + */ + why = netfs_folio_trace_redirtied; + if (!folio_test_dirty(folio)) { + folio_detach_private(folio); + gcount++; + why = netfs_folio_trace_clear_g; + } + } + +end_wb: + trace_netfs_folio(folio, why); + folio_end_writeback(folio); + return gcount; +} + +/* + * Get hold of a folio we have under writeback. We don't want to get the + * refcount on it. + */ +static struct folio *netfs_writeback_lookup_folio(struct netfs_io_request *wreq, loff_t pos) +{ + XA_STATE(xas, &wreq->mapping->i_pages, pos / PAGE_SIZE); + struct folio *folio; + + rcu_read_lock(); + + for (;;) { + xas_reset(&xas); + folio = xas_load(&xas); + if (xas_retry(&xas, folio)) + continue; + + if (!folio || xa_is_value(folio)) + kdebug("R=%08x: folio %lx (%llx) not present", + wreq->debug_id, xas.xa_index, pos / PAGE_SIZE); + BUG_ON(!folio || xa_is_value(folio)); + + if (folio == xas_reload(&xas)) + break; + } + + rcu_read_unlock(); + + if (WARN_ONCE(!folio_test_writeback(folio), + "R=%08x: folio %lx is not under writeback\n", + wreq->debug_id, folio->index)) { + trace_netfs_folio(folio, netfs_folio_trace_not_under_wback); + } + return folio; +} + +/* + * Unlock any folios we've finished with. + */ +static void netfs_writeback_unlock_folios(struct netfs_io_request *wreq, + unsigned long long collected_to, + unsigned int *notes) +{ + for (;;) { + struct folio *folio; + struct netfs_folio *finfo; + unsigned long long fpos, fend; + size_t fsize, flen; + + folio = netfs_writeback_lookup_folio(wreq, wreq->cleaned_to); + + fpos = folio_pos(folio); + fsize = folio_size(folio); + finfo = netfs_folio_info(folio); + flen = finfo ? finfo->dirty_offset + finfo->dirty_len : fsize; + + fend = min_t(unsigned long long, fpos + flen, wreq->i_size); + + trace_netfs_collect_folio(wreq, folio, fend, collected_to); + + if (fpos + fsize > wreq->contiguity) { + trace_netfs_collect_contig(wreq, fpos + fsize, + netfs_contig_trace_unlock); + wreq->contiguity = fpos + fsize; + } + + /* Unlock any folio we've transferred all of. */ + if (collected_to < fend) + break; + + wreq->nr_group_rel += netfs_folio_written_back(folio); + wreq->cleaned_to = fpos + fsize; + *notes |= MADE_PROGRESS; + + if (fpos + fsize >= collected_to) + break; + } +} + +/* + * Perform retries on the streams that need it. + */ +static void netfs_retry_write_stream(struct netfs_io_request *wreq, + struct netfs_io_stream *stream) +{ + struct list_head *next; + + kenter("R=%x[%x:]", wreq->debug_id, stream->stream_nr); + + if (list_empty(&stream->subrequests)) + return; + + if (stream->source == NETFS_UPLOAD_TO_SERVER && + wreq->netfs_ops->retry_request) + wreq->netfs_ops->retry_request(wreq, stream); + + if (unlikely(stream->failed)) + return; + + /* If there's no renegotiation to do, just resend each failed subreq. */ + if (!stream->prepare_write) { + struct netfs_io_subrequest *subreq; + + list_for_each_entry(subreq, &stream->subrequests, rreq_link) { + if (test_bit(NETFS_SREQ_FAILED, &subreq->flags)) + break; + if (__test_and_clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags)) { + __set_bit(NETFS_SREQ_RETRYING, &subreq->flags); + netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit); + netfs_reissue_write(stream, subreq); + } + } + return; + } + + next = stream->subrequests.next; + + do { + struct netfs_io_subrequest *subreq = NULL, *from, *to, *tmp; + unsigned long long start, len; + size_t part; + bool boundary = false; + + /* Go through the stream and find the next span of contiguous + * data that we then rejig (cifs, for example, needs the wsize + * renegotiating) and reissue. + */ + from = list_entry(next, struct netfs_io_subrequest, rreq_link); + to = from; + start = from->start + from->transferred; + len = from->len - from->transferred; + + if (test_bit(NETFS_SREQ_FAILED, &from->flags) || + !test_bit(NETFS_SREQ_NEED_RETRY, &from->flags)) + return; + + list_for_each_continue(next, &stream->subrequests) { + subreq = list_entry(next, struct netfs_io_subrequest, rreq_link); + if (subreq->start + subreq->transferred != start + len || + test_bit(NETFS_SREQ_BOUNDARY, &subreq->flags) || + !test_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags)) + break; + to = subreq; + len += to->len; + } + + /* Work through the sublist. */ + subreq = from; + list_for_each_entry_from(subreq, &stream->subrequests, rreq_link) { + if (!len) + break; + /* Renegotiate max_len (wsize) */ + trace_netfs_sreq(subreq, netfs_sreq_trace_retry); + __clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags); + __set_bit(NETFS_SREQ_RETRYING, &subreq->flags); + stream->prepare_write(subreq); + + part = min(len, subreq->max_len); + subreq->len = part; + subreq->start = start; + subreq->transferred = 0; + len -= part; + start += part; + if (len && subreq == to && + __test_and_clear_bit(NETFS_SREQ_BOUNDARY, &to->flags)) + boundary = true; + + netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit); + netfs_reissue_write(stream, subreq); + if (subreq == to) + break; + } + + /* If we managed to use fewer subreqs, we can discard the + * excess; if we used the same number, then we're done. + */ + if (!len) { + if (subreq == to) + continue; + list_for_each_entry_safe_from(subreq, tmp, + &stream->subrequests, rreq_link) { + trace_netfs_sreq(subreq, netfs_sreq_trace_discard); + list_del(&subreq->rreq_link); + netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_done); + if (subreq == to) + break; + } + continue; + } + + /* We ran out of subrequests, so we need to allocate some more + * and insert them after. + */ + do { + subreq = netfs_alloc_subrequest(wreq); + subreq->source = to->source; + subreq->start = start; + subreq->max_len = len; + subreq->max_nr_segs = INT_MAX; + subreq->debug_index = atomic_inc_return(&wreq->subreq_counter); + subreq->stream_nr = to->stream_nr; + __set_bit(NETFS_SREQ_RETRYING, &subreq->flags); + + trace_netfs_sreq_ref(wreq->debug_id, subreq->debug_index, + refcount_read(&subreq->ref), + netfs_sreq_trace_new); + netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit); + + list_add(&subreq->rreq_link, &to->rreq_link); + to = list_next_entry(to, rreq_link); + trace_netfs_sreq(subreq, netfs_sreq_trace_retry); + + switch (stream->source) { + case NETFS_UPLOAD_TO_SERVER: + netfs_stat(&netfs_n_wh_upload); + subreq->max_len = min(len, wreq->wsize); + break; + case NETFS_WRITE_TO_CACHE: + netfs_stat(&netfs_n_wh_write); + break; + default: + WARN_ON_ONCE(1); + } + + stream->prepare_write(subreq); + + part = min(len, subreq->max_len); + subreq->len = subreq->transferred + part; + len -= part; + start += part; + if (!len && boundary) { + __set_bit(NETFS_SREQ_BOUNDARY, &to->flags); + boundary = false; + } + + netfs_reissue_write(stream, subreq); + if (!len) + break; + + } while (len); + + } while (!list_is_head(next, &stream->subrequests)); +} + +/* + * Perform retries on the streams that need it. If we're doing content + * encryption and the server copy changed due to a third-party write, we may + * need to do an RMW cycle and also rewrite the data to the cache. + */ +static void netfs_retry_writes(struct netfs_io_request *wreq) +{ + struct netfs_io_subrequest *subreq; + struct netfs_io_stream *stream; + int s; + + /* Wait for all outstanding I/O to quiesce before performing retries as + * we may need to renegotiate the I/O sizes. + */ + for (s = 0; s < NR_IO_STREAMS; s++) { + stream = &wreq->io_streams[s]; + if (!stream->active) + continue; + + list_for_each_entry(subreq, &stream->subrequests, rreq_link) { + wait_on_bit(&subreq->flags, NETFS_SREQ_IN_PROGRESS, + TASK_UNINTERRUPTIBLE); + } + } + + // TODO: Enc: Fetch changed partial pages + // TODO: Enc: Reencrypt content if needed. + // TODO: Enc: Wind back transferred point. + // TODO: Enc: Mark cache pages for retry. + + for (s = 0; s < NR_IO_STREAMS; s++) { + stream = &wreq->io_streams[s]; + if (stream->need_retry) { + stream->need_retry = false; + netfs_retry_write_stream(wreq, stream); + } + } +} + +/* + * Collect and assess the results of various write subrequests. We may need to + * retry some of the results - or even do an RMW cycle for content crypto. + * + * Note that we have a number of parallel, overlapping lists of subrequests, + * one to the server and one to the local cache for example, which may not be + * the same size or starting position and may not even correspond in boundary + * alignment. + */ +static void netfs_collect_write_results(struct netfs_io_request *wreq) +{ + struct netfs_io_subrequest *front, *remove; + struct netfs_io_stream *stream; + unsigned long long collected_to; + unsigned int notes; + int s; + + kenter("%llx-%llx", wreq->start, wreq->start + wreq->len); + trace_netfs_collect(wreq); + trace_netfs_rreq(wreq, netfs_rreq_trace_collect); + +reassess_streams: + smp_rmb(); + collected_to = ULLONG_MAX; + if (wreq->origin == NETFS_WRITEBACK) + notes = ALL_EMPTY | BUFFERED | MAYBE_DISCONTIG; + else if (wreq->origin == NETFS_WRITETHROUGH) + notes = ALL_EMPTY | BUFFERED; + else + notes = ALL_EMPTY; + + /* Remove completed subrequests from the front of the streams and + * advance the completion point on each stream. We stop when we hit + * something that's in progress. The issuer thread may be adding stuff + * to the tail whilst we're doing this. + * + * We must not, however, merge in discontiguities that span whole + * folios that aren't under writeback. This is made more complicated + * by the folios in the gap being of unpredictable sizes - if they even + * exist - but we don't want to look them up. + */ + for (s = 0; s < NR_IO_STREAMS; s++) { + loff_t rstart, rend; + + stream = &wreq->io_streams[s]; + /* Read active flag before list pointers */ + if (!smp_load_acquire(&stream->active)) + continue; + + front = stream->front; + while (front) { + trace_netfs_collect_sreq(wreq, front); + //kdebug("sreq [%x] %llx %zx/%zx", + // front->debug_index, front->start, front->transferred, front->len); + + /* Stall if there may be a discontinuity. */ + rstart = round_down(front->start, PAGE_SIZE); + if (rstart > wreq->contiguity) { + if (wreq->contiguity > stream->collected_to) { + trace_netfs_collect_gap(wreq, stream, + wreq->contiguity, 'D'); + stream->collected_to = wreq->contiguity; + } + notes |= REASSESS_DISCONTIG; + break; + } + rend = round_up(front->start + front->len, PAGE_SIZE); + if (rend > wreq->contiguity) { + trace_netfs_collect_contig(wreq, rend, + netfs_contig_trace_collect); + wreq->contiguity = rend; + if (notes & REASSESS_DISCONTIG) + notes |= NEED_REASSESS; + } + notes &= ~MAYBE_DISCONTIG; + + /* Stall if the front is still undergoing I/O. */ + if (test_bit(NETFS_SREQ_IN_PROGRESS, &front->flags)) { + notes |= HIT_PENDING; + break; + } + smp_rmb(); /* Read counters after I-P flag. */ + + if (stream->failed) { + stream->collected_to = front->start + front->len; + notes |= MADE_PROGRESS | SAW_FAILURE; + goto cancel; + } + if (front->start + front->transferred > stream->collected_to) { + stream->collected_to = front->start + front->transferred; + stream->transferred = stream->collected_to - wreq->start; + notes |= MADE_PROGRESS; + } + if (test_bit(NETFS_SREQ_FAILED, &front->flags)) { + stream->failed = true; + stream->error = front->error; + if (stream->source == NETFS_UPLOAD_TO_SERVER) + mapping_set_error(wreq->mapping, front->error); + notes |= NEED_REASSESS | SAW_FAILURE; + break; + } + if (front->transferred < front->len) { + stream->need_retry = true; + notes |= NEED_RETRY | MADE_PROGRESS; + break; + } + + cancel: + /* Remove if completely consumed. */ + spin_lock(&wreq->lock); + + remove = front; + list_del_init(&front->rreq_link); + front = list_first_entry_or_null(&stream->subrequests, + struct netfs_io_subrequest, rreq_link); + stream->front = front; + if (!front) { + unsigned long long jump_to = atomic64_read(&wreq->issued_to); + + if (stream->collected_to < jump_to) { + trace_netfs_collect_gap(wreq, stream, jump_to, 'A'); + stream->collected_to = jump_to; + } + } + + spin_unlock(&wreq->lock); + netfs_put_subrequest(remove, false, + notes & SAW_FAILURE ? + netfs_sreq_trace_put_cancel : + netfs_sreq_trace_put_done); + } + + if (front) + notes &= ~ALL_EMPTY; + else + notes |= SOME_EMPTY; + + if (stream->collected_to < collected_to) + collected_to = stream->collected_to; + } + + if (collected_to != ULLONG_MAX && collected_to > wreq->collected_to) + wreq->collected_to = collected_to; + + /* If we have an empty stream, we need to jump it forward over any gap + * otherwise the collection point will never advance. + * + * Note that the issuer always adds to the stream with the lowest + * so-far submitted start, so if we see two consecutive subreqs in one + * stream with nothing between then in another stream, then the second + * stream has a gap that can be jumped. + */ + if (notes & SOME_EMPTY) { + unsigned long long jump_to = wreq->start + READ_ONCE(wreq->submitted); + + for (s = 0; s < NR_IO_STREAMS; s++) { + stream = &wreq->io_streams[s]; + if (stream->active && + stream->front && + stream->front->start < jump_to) + jump_to = stream->front->start; + } + + for (s = 0; s < NR_IO_STREAMS; s++) { + stream = &wreq->io_streams[s]; + if (stream->active && + !stream->front && + stream->collected_to < jump_to) { + trace_netfs_collect_gap(wreq, stream, jump_to, 'B'); + stream->collected_to = jump_to; + } + } + } + + for (s = 0; s < NR_IO_STREAMS; s++) { + stream = &wreq->io_streams[s]; + if (stream->active) + trace_netfs_collect_stream(wreq, stream); + } + + trace_netfs_collect_state(wreq, wreq->collected_to, notes); + + /* Unlock any folios that we have now finished with. */ + if (notes & BUFFERED) { + unsigned long long clean_to = min(wreq->collected_to, wreq->contiguity); + + if (wreq->cleaned_to < clean_to) + netfs_writeback_unlock_folios(wreq, clean_to, ¬es); + } else { + wreq->cleaned_to = wreq->collected_to; + } + + // TODO: Discard encryption buffers + + /* If all streams are discontiguous with the last folio we cleared, we + * may need to skip a set of folios. + */ + if ((notes & (MAYBE_DISCONTIG | ALL_EMPTY)) == MAYBE_DISCONTIG) { + unsigned long long jump_to = ULLONG_MAX; + + for (s = 0; s < NR_IO_STREAMS; s++) { + stream = &wreq->io_streams[s]; + if (stream->active && stream->front && + stream->front->start < jump_to) + jump_to = stream->front->start; + } + + trace_netfs_collect_contig(wreq, jump_to, netfs_contig_trace_jump); + wreq->contiguity = jump_to; + wreq->cleaned_to = jump_to; + wreq->collected_to = jump_to; + for (s = 0; s < NR_IO_STREAMS; s++) { + stream = &wreq->io_streams[s]; + if (stream->collected_to < jump_to) + stream->collected_to = jump_to; + } + //cond_resched(); + notes |= MADE_PROGRESS; + goto reassess_streams; + } + + if (notes & NEED_RETRY) + goto need_retry; + if ((notes & MADE_PROGRESS) && test_bit(NETFS_RREQ_PAUSE, &wreq->flags)) { + trace_netfs_rreq(wreq, netfs_rreq_trace_unpause); + clear_bit_unlock(NETFS_RREQ_PAUSE, &wreq->flags); + wake_up_bit(&wreq->flags, NETFS_RREQ_PAUSE); + } + + if (notes & NEED_REASSESS) { + //cond_resched(); + goto reassess_streams; + } + if (notes & MADE_PROGRESS) { + //cond_resched(); + goto reassess_streams; + } + +out: + netfs_put_group_many(wreq->group, wreq->nr_group_rel); + wreq->nr_group_rel = 0; + kleave(" = %x", notes); + return; + +need_retry: + /* Okay... We're going to have to retry one or both streams. Note + * that any partially completed op will have had any wholly transferred + * folios removed from it. + */ + kdebug("retry"); + netfs_retry_writes(wreq); + goto out; +} + +/* + * Perform the collection of subrequests, folios and encryption buffers. + */ +void netfs_write_collection_worker(struct work_struct *work) +{ + struct netfs_io_request *wreq = container_of(work, struct netfs_io_request, work); + struct netfs_inode *ictx = netfs_inode(wreq->inode); + size_t transferred; + int s; + + kenter("R=%x", wreq->debug_id); + + netfs_see_request(wreq, netfs_rreq_trace_see_work); + if (!test_bit(NETFS_RREQ_IN_PROGRESS, &wreq->flags)) { + netfs_put_request(wreq, false, netfs_rreq_trace_put_work); + return; + } + + netfs_collect_write_results(wreq); + + /* We're done when the app thread has finished posting subreqs and all + * the queues in all the streams are empty. + */ + if (!test_bit(NETFS_RREQ_ALL_QUEUED, &wreq->flags)) { + netfs_put_request(wreq, false, netfs_rreq_trace_put_work); + return; + } + smp_rmb(); /* Read ALL_QUEUED before lists. */ + + transferred = LONG_MAX; + for (s = 0; s < NR_IO_STREAMS; s++) { + struct netfs_io_stream *stream = &wreq->io_streams[s]; + if (!stream->active) + continue; + if (!list_empty(&stream->subrequests)) { + netfs_put_request(wreq, false, netfs_rreq_trace_put_work); + return; + } + if (stream->transferred < transferred) + transferred = stream->transferred; + } + + /* Okay, declare that all I/O is complete. */ + wreq->transferred = transferred; + trace_netfs_rreq(wreq, netfs_rreq_trace_write_done); + + if (wreq->io_streams[1].active && + wreq->io_streams[1].failed) { + /* Cache write failure doesn't prevent writeback completion + * unless we're in disconnected mode. + */ + ictx->ops->invalidate_cache(wreq); + } + + if (wreq->cleanup) + wreq->cleanup(wreq); + + if (wreq->origin == NETFS_DIO_WRITE && + wreq->mapping->nrpages) { + /* mmap may have got underfoot and we may now have folios + * locally covering the region we just wrote. Attempt to + * discard the folios, but leave in place any modified locally. + * ->write_iter() is prevented from interfering by the DIO + * counter. + */ + pgoff_t first = wreq->start >> PAGE_SHIFT; + pgoff_t last = (wreq->start + wreq->transferred - 1) >> PAGE_SHIFT; + invalidate_inode_pages2_range(wreq->mapping, first, last); + } + + if (wreq->origin == NETFS_DIO_WRITE) + inode_dio_end(wreq->inode); + + kdebug("finished"); + trace_netfs_rreq(wreq, netfs_rreq_trace_wake_ip); + clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &wreq->flags); + wake_up_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS); + + if (wreq->iocb) { + size_t written = min(wreq->transferred, wreq->len); + wreq->iocb->ki_pos += written; + if (wreq->iocb->ki_complete) + wreq->iocb->ki_complete( + wreq->iocb, wreq->error ? wreq->error : written); + wreq->iocb = VFS_PTR_POISON; + } + + netfs_clear_subrequests(wreq, false); + netfs_put_request(wreq, false, netfs_rreq_trace_put_work_complete); +} + +/* + * Wake the collection work item. + */ +void netfs_wake_write_collector(struct netfs_io_request *wreq, bool was_async) +{ + if (!work_pending(&wreq->work)) { + netfs_get_request(wreq, netfs_rreq_trace_get_work); + if (!queue_work(system_unbound_wq, &wreq->work)) + netfs_put_request(wreq, was_async, netfs_rreq_trace_put_work_nq); + } +} + +/** + * netfs_write_subrequest_terminated - Note the termination of a write operation. + * @_op: The I/O request that has terminated. + * @transferred_or_error: The amount of data transferred or an error code. + * @was_async: The termination was asynchronous + * + * This tells the library that a contributory write I/O operation has + * terminated, one way or another, and that it should collect the results. + * + * The caller indicates in @transferred_or_error the outcome of the operation, + * supplying a positive value to indicate the number of bytes transferred or a + * negative error code. The library will look after reissuing I/O operations + * as appropriate and writing downloaded data to the cache. + * + * If @was_async is true, the caller might be running in softirq or interrupt + * context and we can't sleep. + * + * When this is called, ownership of the subrequest is transferred back to the + * library, along with a ref. + * + * Note that %_op is a void* so that the function can be passed to + * kiocb::term_func without the need for a casting wrapper. + */ +void netfs_write_subrequest_terminated(void *_op, ssize_t transferred_or_error, + bool was_async) +{ + struct netfs_io_subrequest *subreq = _op; + struct netfs_io_request *wreq = subreq->rreq; + struct netfs_io_stream *stream = &wreq->io_streams[subreq->stream_nr]; + + kenter("%x[%x] %zd", wreq->debug_id, subreq->debug_index, transferred_or_error); + + switch (subreq->source) { + case NETFS_UPLOAD_TO_SERVER: + netfs_stat(&netfs_n_wh_upload_done); + break; + case NETFS_WRITE_TO_CACHE: + netfs_stat(&netfs_n_wh_write_done); + break; + case NETFS_INVALID_WRITE: + break; + default: + BUG(); + } + + if (IS_ERR_VALUE(transferred_or_error)) { + subreq->error = transferred_or_error; + if (subreq->error == -EAGAIN) + set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags); + else + set_bit(NETFS_SREQ_FAILED, &subreq->flags); + trace_netfs_failure(wreq, subreq, transferred_or_error, netfs_fail_write); + + switch (subreq->source) { + case NETFS_WRITE_TO_CACHE: + netfs_stat(&netfs_n_wh_write_failed); + break; + case NETFS_UPLOAD_TO_SERVER: + netfs_stat(&netfs_n_wh_upload_failed); + break; + default: + break; + } + trace_netfs_rreq(wreq, netfs_rreq_trace_set_pause); + set_bit(NETFS_RREQ_PAUSE, &wreq->flags); + } else { + if (WARN(transferred_or_error > subreq->len - subreq->transferred, + "Subreq excess write: R=%x[%x] %zd > %zu - %zu", + wreq->debug_id, subreq->debug_index, + transferred_or_error, subreq->len, subreq->transferred)) + transferred_or_error = subreq->len - subreq->transferred; + + subreq->error = 0; + subreq->transferred += transferred_or_error; + + if (subreq->transferred < subreq->len) + set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags); + } + + trace_netfs_sreq(subreq, netfs_sreq_trace_terminated); + + clear_bit_unlock(NETFS_SREQ_IN_PROGRESS, &subreq->flags); + wake_up_bit(&subreq->flags, NETFS_SREQ_IN_PROGRESS); + + /* If we are at the head of the queue, wake up the collector, + * transferring a ref to it if we were the ones to do so. + */ + if (list_is_first(&subreq->rreq_link, &stream->subrequests)) + netfs_wake_write_collector(wreq, was_async); + + netfs_put_subrequest(subreq, was_async, netfs_sreq_trace_put_terminated); +} +EXPORT_SYMBOL(netfs_write_subrequest_terminated); |