diff options
Diffstat (limited to 'fs/netfs/misc.c')
| -rw-r--r-- | fs/netfs/misc.c | 546 |
1 files changed, 546 insertions, 0 deletions
diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c new file mode 100644 index 000000000000..6df89c92b10b --- /dev/null +++ b/fs/netfs/misc.c @@ -0,0 +1,546 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Miscellaneous routines. + * + * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/swap.h> +#include "internal.h" + +/** + * netfs_alloc_folioq_buffer - Allocate buffer space into a folio queue + * @mapping: Address space to set on the folio (or NULL). + * @_buffer: Pointer to the folio queue to add to (may point to a NULL; updated). + * @_cur_size: Current size of the buffer (updated). + * @size: Target size of the buffer. + * @gfp: The allocation constraints. + */ +int netfs_alloc_folioq_buffer(struct address_space *mapping, + struct folio_queue **_buffer, + size_t *_cur_size, ssize_t size, gfp_t gfp) +{ + struct folio_queue *tail = *_buffer, *p; + + size = round_up(size, PAGE_SIZE); + if (*_cur_size >= size) + return 0; + + if (tail) + while (tail->next) + tail = tail->next; + + do { + struct folio *folio; + int order = 0, slot; + + if (!tail || folioq_full(tail)) { + p = netfs_folioq_alloc(0, GFP_NOFS, netfs_trace_folioq_alloc_buffer); + if (!p) + return -ENOMEM; + if (tail) { + tail->next = p; + p->prev = tail; + } else { + *_buffer = p; + } + tail = p; + } + + if (size - *_cur_size > PAGE_SIZE) + order = umin(ilog2(size - *_cur_size) - PAGE_SHIFT, + MAX_PAGECACHE_ORDER); + + folio = folio_alloc(gfp, order); + if (!folio && order > 0) + folio = folio_alloc(gfp, 0); + if (!folio) + return -ENOMEM; + + folio->mapping = mapping; + folio->index = *_cur_size / PAGE_SIZE; + trace_netfs_folio(folio, netfs_folio_trace_alloc_buffer); + slot = folioq_append_mark(tail, folio); + *_cur_size += folioq_folio_size(tail, slot); + } while (*_cur_size < size); + + return 0; +} +EXPORT_SYMBOL(netfs_alloc_folioq_buffer); + +/** + * netfs_free_folioq_buffer - Free a folio queue. + * @fq: The start of the folio queue to free + * + * Free up a chain of folio_queues and, if marked, the marked folios they point + * to. + */ +void netfs_free_folioq_buffer(struct folio_queue *fq) +{ + struct folio_queue *next; + struct folio_batch fbatch; + + folio_batch_init(&fbatch); + + for (; fq; fq = next) { + for (int slot = 0; slot < folioq_count(fq); slot++) { + struct folio *folio = folioq_folio(fq, slot); + + if (!folio || + !folioq_is_marked(fq, slot)) + continue; + + trace_netfs_folio(folio, netfs_folio_trace_put); + if (folio_batch_add(&fbatch, folio)) + folio_batch_release(&fbatch); + } + + netfs_stat_d(&netfs_n_folioq); + next = fq->next; + kfree(fq); + } + + folio_batch_release(&fbatch); +} +EXPORT_SYMBOL(netfs_free_folioq_buffer); + +/* + * Reset the subrequest iterator to refer just to the region remaining to be + * read. The iterator may or may not have been advanced by socket ops or + * extraction ops to an extent that may or may not match the amount actually + * read. + */ +void netfs_reset_iter(struct netfs_io_subrequest *subreq) +{ + struct iov_iter *io_iter = &subreq->io_iter; + size_t remain = subreq->len - subreq->transferred; + + if (io_iter->count > remain) + iov_iter_advance(io_iter, io_iter->count - remain); + else if (io_iter->count < remain) + iov_iter_revert(io_iter, remain - io_iter->count); + iov_iter_truncate(&subreq->io_iter, remain); +} + +/** + * netfs_dirty_folio - Mark folio dirty and pin a cache object for writeback + * @mapping: The mapping the folio belongs to. + * @folio: The folio being dirtied. + * + * Set the dirty flag on a folio and pin an in-use cache object in memory so + * that writeback can later write to it. This is intended to be called from + * the filesystem's ->dirty_folio() method. + * + * Return: true if the dirty flag was set on the folio, false otherwise. + */ +bool netfs_dirty_folio(struct address_space *mapping, struct folio *folio) +{ + struct inode *inode = mapping->host; + struct netfs_inode *ictx = netfs_inode(inode); + struct fscache_cookie *cookie = netfs_i_cookie(ictx); + bool need_use = false; + + _enter(""); + + if (!filemap_dirty_folio(mapping, folio)) + return false; + if (!fscache_cookie_valid(cookie)) + return true; + + if (!(inode_state_read_once(inode) & I_PINNING_NETFS_WB)) { + spin_lock(&inode->i_lock); + if (!(inode_state_read(inode) & I_PINNING_NETFS_WB)) { + inode_state_set(inode, I_PINNING_NETFS_WB); + need_use = true; + } + spin_unlock(&inode->i_lock); + + if (need_use) + fscache_use_cookie(cookie, true); + } + return true; +} +EXPORT_SYMBOL(netfs_dirty_folio); + +/** + * netfs_unpin_writeback - Unpin writeback resources + * @inode: The inode on which the cookie resides + * @wbc: The writeback control + * + * Unpin the writeback resources pinned by netfs_dirty_folio(). This is + * intended to be called as/by the netfs's ->write_inode() method. + */ +int netfs_unpin_writeback(struct inode *inode, struct writeback_control *wbc) +{ + struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode)); + + if (wbc->unpinned_netfs_wb) + fscache_unuse_cookie(cookie, NULL, NULL); + return 0; +} +EXPORT_SYMBOL(netfs_unpin_writeback); + +/** + * netfs_clear_inode_writeback - Clear writeback resources pinned by an inode + * @inode: The inode to clean up + * @aux: Auxiliary data to apply to the inode + * + * Clear any writeback resources held by an inode when the inode is evicted. + * This must be called before clear_inode() is called. + */ +void netfs_clear_inode_writeback(struct inode *inode, const void *aux) +{ + struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode)); + + if (inode_state_read_once(inode) & I_PINNING_NETFS_WB) { + loff_t i_size = i_size_read(inode); + fscache_unuse_cookie(cookie, aux, &i_size); + } +} +EXPORT_SYMBOL(netfs_clear_inode_writeback); + +/** + * netfs_invalidate_folio - Invalidate or partially invalidate a folio + * @folio: Folio proposed for release + * @offset: Offset of the invalidated region + * @length: Length of the invalidated region + * + * Invalidate part or all of a folio for a network filesystem. The folio will + * be removed afterwards if the invalidated region covers the entire folio. + */ +void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length) +{ + struct netfs_folio *finfo; + struct netfs_inode *ctx = netfs_inode(folio_inode(folio)); + size_t flen = folio_size(folio); + + _enter("{%lx},%zx,%zx", folio->index, offset, length); + + if (offset == 0 && length == flen) { + unsigned long long i_size = i_size_read(&ctx->inode); + unsigned long long fpos = folio_pos(folio), end; + + end = umin(fpos + flen, i_size); + if (fpos < i_size && end > ctx->zero_point) + ctx->zero_point = end; + } + + folio_wait_private_2(folio); /* [DEPRECATED] */ + + if (!folio_test_private(folio)) + return; + + finfo = netfs_folio_info(folio); + + if (offset == 0 && length >= flen) + goto erase_completely; + + if (finfo) { + /* We have a partially uptodate page from a streaming write. */ + unsigned int fstart = finfo->dirty_offset; + unsigned int fend = fstart + finfo->dirty_len; + unsigned int iend = offset + length; + + if (offset >= fend) + return; + if (iend <= fstart) + return; + + /* The invalidation region overlaps the data. If the region + * covers the start of the data, we either move along the start + * or just erase the data entirely. + */ + if (offset <= fstart) { + if (iend >= fend) + goto erase_completely; + /* Move the start of the data. */ + finfo->dirty_len = fend - iend; + finfo->dirty_offset = offset; + return; + } + + /* Reduce the length of the data if the invalidation region + * covers the tail part. + */ + if (iend >= fend) { + finfo->dirty_len = offset - fstart; + return; + } + + /* A partial write was split. The caller has already zeroed + * it, so just absorb the hole. + */ + } + return; + +erase_completely: + netfs_put_group(netfs_folio_group(folio)); + folio_detach_private(folio); + folio_clear_uptodate(folio); + kfree(finfo); + return; +} +EXPORT_SYMBOL(netfs_invalidate_folio); + +/** + * netfs_release_folio - Try to release a folio + * @folio: Folio proposed for release + * @gfp: Flags qualifying the release + * + * Request release of a folio and clean up its private state if it's not busy. + * Returns true if the folio can now be released, false if not + */ +bool netfs_release_folio(struct folio *folio, gfp_t gfp) +{ + struct netfs_inode *ctx = netfs_inode(folio_inode(folio)); + unsigned long long end; + + if (folio_test_dirty(folio)) + return false; + + end = umin(folio_next_pos(folio), i_size_read(&ctx->inode)); + if (end > ctx->zero_point) + ctx->zero_point = end; + + if (folio_test_private(folio)) + return false; + if (unlikely(folio_test_private_2(folio))) { /* [DEPRECATED] */ + if (current_is_kswapd() || !(gfp & __GFP_FS)) + return false; + folio_wait_private_2(folio); + } + fscache_note_page_release(netfs_i_cookie(ctx)); + return true; +} +EXPORT_SYMBOL(netfs_release_folio); + +/* + * Wake the collection work item. + */ +void netfs_wake_collector(struct netfs_io_request *rreq) +{ + if (test_bit(NETFS_RREQ_OFFLOAD_COLLECTION, &rreq->flags) && + !test_bit(NETFS_RREQ_RETRYING, &rreq->flags)) { + queue_work(system_dfl_wq, &rreq->work); + } else { + trace_netfs_rreq(rreq, netfs_rreq_trace_wake_queue); + wake_up(&rreq->waitq); + } +} + +/* + * Mark a subrequest as no longer being in progress and, if need be, wake the + * collector. + */ +void netfs_subreq_clear_in_progress(struct netfs_io_subrequest *subreq) +{ + struct netfs_io_request *rreq = subreq->rreq; + struct netfs_io_stream *stream = &rreq->io_streams[subreq->stream_nr]; + + clear_bit_unlock(NETFS_SREQ_IN_PROGRESS, &subreq->flags); + smp_mb__after_atomic(); /* Clear IN_PROGRESS before task state */ + + /* If we are at the head of the queue, wake up the collector. */ + if (list_is_first(&subreq->rreq_link, &stream->subrequests) || + test_bit(NETFS_RREQ_RETRYING, &rreq->flags)) + netfs_wake_collector(rreq); +} + +/* + * Wait for all outstanding I/O in a stream to quiesce. + */ +void netfs_wait_for_in_progress_stream(struct netfs_io_request *rreq, + struct netfs_io_stream *stream) +{ + struct netfs_io_subrequest *subreq; + DEFINE_WAIT(myself); + + list_for_each_entry(subreq, &stream->subrequests, rreq_link) { + if (!netfs_check_subreq_in_progress(subreq)) + continue; + + trace_netfs_rreq(rreq, netfs_rreq_trace_wait_quiesce); + for (;;) { + prepare_to_wait(&rreq->waitq, &myself, TASK_UNINTERRUPTIBLE); + + if (!netfs_check_subreq_in_progress(subreq)) + break; + + trace_netfs_sreq(subreq, netfs_sreq_trace_wait_for); + schedule(); + } + } + + trace_netfs_rreq(rreq, netfs_rreq_trace_waited_quiesce); + finish_wait(&rreq->waitq, &myself); +} + +/* + * Perform collection in app thread if not offloaded to workqueue. + */ +static int netfs_collect_in_app(struct netfs_io_request *rreq, + bool (*collector)(struct netfs_io_request *rreq)) +{ + bool need_collect = false, inactive = true, done = true; + + if (!netfs_check_rreq_in_progress(rreq)) { + trace_netfs_rreq(rreq, netfs_rreq_trace_recollect); + return 1; /* Done */ + } + + for (int i = 0; i < NR_IO_STREAMS; i++) { + struct netfs_io_subrequest *subreq; + struct netfs_io_stream *stream = &rreq->io_streams[i]; + + if (!stream->active) + continue; + inactive = false; + trace_netfs_collect_stream(rreq, stream); + subreq = list_first_entry_or_null(&stream->subrequests, + struct netfs_io_subrequest, + rreq_link); + if (subreq && + (!netfs_check_subreq_in_progress(subreq) || + test_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags))) { + need_collect = true; + break; + } + if (subreq || !test_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags)) + done = false; + } + + if (!need_collect && !inactive && !done) + return 0; /* Sleep */ + + __set_current_state(TASK_RUNNING); + if (collector(rreq)) { + /* Drop the ref from the NETFS_RREQ_IN_PROGRESS flag. */ + netfs_put_request(rreq, netfs_rreq_trace_put_work_ip); + return 1; /* Done */ + } + + if (inactive) { + WARN(true, "Failed to collect inactive req R=%08x\n", + rreq->debug_id); + cond_resched(); + } + return 2; /* Again */ +} + +/* + * Wait for a request to complete, successfully or otherwise. + */ +static ssize_t netfs_wait_for_in_progress(struct netfs_io_request *rreq, + bool (*collector)(struct netfs_io_request *rreq)) +{ + DEFINE_WAIT(myself); + ssize_t ret; + + for (;;) { + prepare_to_wait(&rreq->waitq, &myself, TASK_UNINTERRUPTIBLE); + + if (!test_bit(NETFS_RREQ_OFFLOAD_COLLECTION, &rreq->flags)) { + switch (netfs_collect_in_app(rreq, collector)) { + case 0: + break; + case 1: + goto all_collected; + case 2: + if (!netfs_check_rreq_in_progress(rreq)) + break; + cond_resched(); + continue; + } + } + + if (!netfs_check_rreq_in_progress(rreq)) + break; + + trace_netfs_rreq(rreq, netfs_rreq_trace_wait_ip); + schedule(); + } + +all_collected: + trace_netfs_rreq(rreq, netfs_rreq_trace_waited_ip); + finish_wait(&rreq->waitq, &myself); + + ret = rreq->error; + if (ret == 0) { + ret = rreq->transferred; + switch (rreq->origin) { + case NETFS_DIO_READ: + case NETFS_DIO_WRITE: + case NETFS_READ_SINGLE: + case NETFS_UNBUFFERED_READ: + case NETFS_UNBUFFERED_WRITE: + break; + default: + if (rreq->submitted < rreq->len) { + trace_netfs_failure(rreq, NULL, ret, netfs_fail_short_read); + ret = -EIO; + } + break; + } + } + + return ret; +} + +ssize_t netfs_wait_for_read(struct netfs_io_request *rreq) +{ + return netfs_wait_for_in_progress(rreq, netfs_read_collection); +} + +ssize_t netfs_wait_for_write(struct netfs_io_request *rreq) +{ + return netfs_wait_for_in_progress(rreq, netfs_write_collection); +} + +/* + * Wait for a paused operation to unpause or complete in some manner. + */ +static void netfs_wait_for_pause(struct netfs_io_request *rreq, + bool (*collector)(struct netfs_io_request *rreq)) +{ + DEFINE_WAIT(myself); + + for (;;) { + trace_netfs_rreq(rreq, netfs_rreq_trace_wait_pause); + prepare_to_wait(&rreq->waitq, &myself, TASK_UNINTERRUPTIBLE); + + if (!test_bit(NETFS_RREQ_OFFLOAD_COLLECTION, &rreq->flags)) { + switch (netfs_collect_in_app(rreq, collector)) { + case 0: + break; + case 1: + goto all_collected; + case 2: + if (!netfs_check_rreq_in_progress(rreq) || + !test_bit(NETFS_RREQ_PAUSE, &rreq->flags)) + break; + cond_resched(); + continue; + } + } + + if (!netfs_check_rreq_in_progress(rreq) || + !test_bit(NETFS_RREQ_PAUSE, &rreq->flags)) + break; + + schedule(); + } + +all_collected: + trace_netfs_rreq(rreq, netfs_rreq_trace_waited_pause); + finish_wait(&rreq->waitq, &myself); +} + +void netfs_wait_for_paused_read(struct netfs_io_request *rreq) +{ + return netfs_wait_for_pause(rreq, netfs_read_collection); +} + +void netfs_wait_for_paused_write(struct netfs_io_request *rreq) +{ + return netfs_wait_for_pause(rreq, netfs_write_collection); +} |