| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* Network filesystem high-level buffered read support. |
| * |
| * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| */ |
| |
| #include <linux/export.h> |
| #include <linux/task_io_accounting_ops.h> |
| #include "internal.h" |
| |
| /* |
| * [DEPRECATED] Unlock the folios in a read operation for when the filesystem |
| * is using PG_private_2 and direct writing to the cache from here rather than |
| * marking the page for writeback. |
| * |
| * Note that we don't touch folio->private in this code. |
| */ |
| static void netfs_rreq_unlock_folios_pgpriv2(struct netfs_io_request *rreq, |
| size_t *account) |
| { |
| struct netfs_io_subrequest *subreq; |
| struct folio *folio; |
| pgoff_t start_page = rreq->start / PAGE_SIZE; |
| pgoff_t last_page = ((rreq->start + rreq->len) / PAGE_SIZE) - 1; |
| bool subreq_failed = false; |
| |
| XA_STATE(xas, &rreq->mapping->i_pages, start_page); |
| |
| /* Walk through the pagecache and the I/O request lists simultaneously. |
| * We may have a mixture of cached and uncached sections and we only |
| * really want to write out the uncached sections. This is slightly |
| * complicated by the possibility that we might have huge pages with a |
| * mixture inside. |
| */ |
| subreq = list_first_entry(&rreq->subrequests, |
| struct netfs_io_subrequest, rreq_link); |
| subreq_failed = (subreq->error < 0); |
| |
| trace_netfs_rreq(rreq, netfs_rreq_trace_unlock_pgpriv2); |
| |
| rcu_read_lock(); |
| xas_for_each(&xas, folio, last_page) { |
| loff_t pg_end; |
| bool pg_failed = false; |
| bool folio_started = false; |
| |
| if (xas_retry(&xas, folio)) |
| continue; |
| |
| pg_end = folio_pos(folio) + folio_size(folio) - 1; |
| |
| for (;;) { |
| loff_t sreq_end; |
| |
| if (!subreq) { |
| pg_failed = true; |
| break; |
| } |
| |
| if (!folio_started && |
| test_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags) && |
| fscache_operation_valid(&rreq->cache_resources)) { |
| trace_netfs_folio(folio, netfs_folio_trace_copy_to_cache); |
| folio_start_private_2(folio); |
| folio_started = true; |
| } |
| |
| pg_failed |= subreq_failed; |
| sreq_end = subreq->start + subreq->len - 1; |
| if (pg_end < sreq_end) |
| break; |
| |
| *account += subreq->transferred; |
| if (!list_is_last(&subreq->rreq_link, &rreq->subrequests)) { |
| subreq = list_next_entry(subreq, rreq_link); |
| subreq_failed = (subreq->error < 0); |
| } else { |
| subreq = NULL; |
| subreq_failed = false; |
| } |
| |
| if (pg_end == sreq_end) |
| break; |
| } |
| |
| if (!pg_failed) { |
| flush_dcache_folio(folio); |
| folio_mark_uptodate(folio); |
| } |
| |
| if (!test_bit(NETFS_RREQ_DONT_UNLOCK_FOLIOS, &rreq->flags)) { |
| if (folio->index == rreq->no_unlock_folio && |
| test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags)) |
| _debug("no unlock"); |
| else |
| folio_unlock(folio); |
| } |
| } |
| rcu_read_unlock(); |
| } |
| |
| /* |
| * Unlock the folios in a read operation. We need to set PG_writeback on any |
| * folios we're going to write back before we unlock them. |
| * |
| * Note that if the deprecated NETFS_RREQ_USE_PGPRIV2 is set then we use |
| * PG_private_2 and do a direct write to the cache from here instead. |
| */ |
| void netfs_rreq_unlock_folios(struct netfs_io_request *rreq) |
| { |
| struct netfs_io_subrequest *subreq; |
| struct netfs_folio *finfo; |
| struct folio *folio; |
| pgoff_t start_page = rreq->start / PAGE_SIZE; |
| pgoff_t last_page = ((rreq->start + rreq->len) / PAGE_SIZE) - 1; |
| size_t account = 0; |
| bool subreq_failed = false; |
| |
| XA_STATE(xas, &rreq->mapping->i_pages, start_page); |
| |
| if (test_bit(NETFS_RREQ_FAILED, &rreq->flags)) { |
| __clear_bit(NETFS_RREQ_COPY_TO_CACHE, &rreq->flags); |
| list_for_each_entry(subreq, &rreq->subrequests, rreq_link) { |
| __clear_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags); |
| } |
| } |
| |
| /* Handle deprecated PG_private_2 case. */ |
| if (test_bit(NETFS_RREQ_USE_PGPRIV2, &rreq->flags)) { |
| netfs_rreq_unlock_folios_pgpriv2(rreq, &account); |
| goto out; |
| } |
| |
| /* Walk through the pagecache and the I/O request lists simultaneously. |
| * We may have a mixture of cached and uncached sections and we only |
| * really want to write out the uncached sections. This is slightly |
| * complicated by the possibility that we might have huge pages with a |
| * mixture inside. |
| */ |
| subreq = list_first_entry(&rreq->subrequests, |
| struct netfs_io_subrequest, rreq_link); |
| subreq_failed = (subreq->error < 0); |
| |
| trace_netfs_rreq(rreq, netfs_rreq_trace_unlock); |
| |
| rcu_read_lock(); |
| xas_for_each(&xas, folio, last_page) { |
| loff_t pg_end; |
| bool pg_failed = false; |
| bool wback_to_cache = false; |
| |
| if (xas_retry(&xas, folio)) |
| continue; |
| |
| pg_end = folio_pos(folio) + folio_size(folio) - 1; |
| |
| for (;;) { |
| loff_t sreq_end; |
| |
| if (!subreq) { |
| pg_failed = true; |
| break; |
| } |
| |
| wback_to_cache |= test_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags); |
| pg_failed |= subreq_failed; |
| sreq_end = subreq->start + subreq->len - 1; |
| if (pg_end < sreq_end) |
| break; |
| |
| account += subreq->transferred; |
| if (!list_is_last(&subreq->rreq_link, &rreq->subrequests)) { |
| subreq = list_next_entry(subreq, rreq_link); |
| subreq_failed = (subreq->error < 0); |
| } else { |
| subreq = NULL; |
| subreq_failed = false; |
| } |
| |
| if (pg_end == sreq_end) |
| break; |
| } |
| |
| if (!pg_failed) { |
| flush_dcache_folio(folio); |
| finfo = netfs_folio_info(folio); |
| if (finfo) { |
| trace_netfs_folio(folio, netfs_folio_trace_filled_gaps); |
| if (finfo->netfs_group) |
| folio_change_private(folio, finfo->netfs_group); |
| else |
| folio_detach_private(folio); |
| kfree(finfo); |
| } |
| folio_mark_uptodate(folio); |
| if (wback_to_cache && !WARN_ON_ONCE(folio_get_private(folio) != NULL)) { |
| trace_netfs_folio(folio, netfs_folio_trace_copy_to_cache); |
| folio_attach_private(folio, NETFS_FOLIO_COPY_TO_CACHE); |
| filemap_dirty_folio(folio->mapping, folio); |
| } |
| } |
| |
| if (!test_bit(NETFS_RREQ_DONT_UNLOCK_FOLIOS, &rreq->flags)) { |
| if (folio->index == rreq->no_unlock_folio && |
| test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags)) |
| _debug("no unlock"); |
| else |
| folio_unlock(folio); |
| } |
| } |
| rcu_read_unlock(); |
| |
| out: |
| task_io_account_read(account); |
| if (rreq->netfs_ops->done) |
| rreq->netfs_ops->done(rreq); |
| } |
| |
| static void netfs_cache_expand_readahead(struct netfs_io_request *rreq, |
| unsigned long long *_start, |
| unsigned long long *_len, |
| unsigned long long i_size) |
| { |
| struct netfs_cache_resources *cres = &rreq->cache_resources; |
| |
| if (cres->ops && cres->ops->expand_readahead) |
| cres->ops->expand_readahead(cres, _start, _len, i_size); |
| } |
| |
| static void netfs_rreq_expand(struct netfs_io_request *rreq, |
| struct readahead_control *ractl) |
| { |
| /* Give the cache a chance to change the request parameters. The |
| * resultant request must contain the original region. |
| */ |
| netfs_cache_expand_readahead(rreq, &rreq->start, &rreq->len, rreq->i_size); |
| |
| /* Give the netfs a chance to change the request parameters. The |
| * resultant request must contain the original region. |
| */ |
| if (rreq->netfs_ops->expand_readahead) |
| rreq->netfs_ops->expand_readahead(rreq); |
| |
| /* Expand the request if the cache wants it to start earlier. Note |
| * that the expansion may get further extended if the VM wishes to |
| * insert THPs and the preferred start and/or end wind up in the middle |
| * of THPs. |
| * |
| * If this is the case, however, the THP size should be an integer |
| * multiple of the cache granule size, so we get a whole number of |
| * granules to deal with. |
| */ |
| if (rreq->start != readahead_pos(ractl) || |
| rreq->len != readahead_length(ractl)) { |
| readahead_expand(ractl, rreq->start, rreq->len); |
| rreq->start = readahead_pos(ractl); |
| rreq->len = readahead_length(ractl); |
| |
| trace_netfs_read(rreq, readahead_pos(ractl), readahead_length(ractl), |
| netfs_read_trace_expanded); |
| } |
| } |
| |
| /* |
| * Begin an operation, and fetch the stored zero point value from the cookie if |
| * available. |
| */ |
| static int netfs_begin_cache_read(struct netfs_io_request *rreq, struct netfs_inode *ctx) |
| { |
| return fscache_begin_read_operation(&rreq->cache_resources, netfs_i_cookie(ctx)); |
| } |
| |
| /** |
| * netfs_readahead - Helper to manage a read request |
| * @ractl: The description of the readahead request |
| * |
| * Fulfil a readahead request by drawing data from the cache if possible, or |
| * the netfs if not. Space beyond the EOF is zero-filled. Multiple I/O |
| * requests from different sources will get munged together. If necessary, the |
| * readahead window can be expanded in either direction to a more convenient |
| * alighment for RPC efficiency or to make storage in the cache feasible. |
| * |
| * The calling netfs must initialise a netfs context contiguous to the vfs |
| * inode before calling this. |
| * |
| * This is usable whether or not caching is enabled. |
| */ |
| void netfs_readahead(struct readahead_control *ractl) |
| { |
| struct netfs_io_request *rreq; |
| struct netfs_inode *ctx = netfs_inode(ractl->mapping->host); |
| int ret; |
| |
| _enter("%lx,%x", readahead_index(ractl), readahead_count(ractl)); |
| |
| if (readahead_count(ractl) == 0) |
| return; |
| |
| rreq = netfs_alloc_request(ractl->mapping, ractl->file, |
| readahead_pos(ractl), |
| readahead_length(ractl), |
| NETFS_READAHEAD); |
| if (IS_ERR(rreq)) |
| return; |
| |
| ret = netfs_begin_cache_read(rreq, ctx); |
| if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) |
| goto cleanup_free; |
| |
| netfs_stat(&netfs_n_rh_readahead); |
| trace_netfs_read(rreq, readahead_pos(ractl), readahead_length(ractl), |
| netfs_read_trace_readahead); |
| |
| netfs_rreq_expand(rreq, ractl); |
| |
| /* Set up the output buffer */ |
| iov_iter_xarray(&rreq->iter, ITER_DEST, &ractl->mapping->i_pages, |
| rreq->start, rreq->len); |
| |
| /* Drop the refs on the folios here rather than in the cache or |
| * filesystem. The locks will be dropped in netfs_rreq_unlock(). |
| */ |
| while (readahead_folio(ractl)) |
| ; |
| |
| netfs_begin_read(rreq, false); |
| netfs_put_request(rreq, false, netfs_rreq_trace_put_return); |
| return; |
| |
| cleanup_free: |
| netfs_put_request(rreq, false, netfs_rreq_trace_put_failed); |
| return; |
| } |
| EXPORT_SYMBOL(netfs_readahead); |
| |
| /** |
| * netfs_read_folio - Helper to manage a read_folio request |
| * @file: The file to read from |
| * @folio: The folio to read |
| * |
| * Fulfil a read_folio request by drawing data from the cache if |
| * possible, or the netfs if not. Space beyond the EOF is zero-filled. |
| * Multiple I/O requests from different sources will get munged together. |
| * |
| * The calling netfs must initialise a netfs context contiguous to the vfs |
| * inode before calling this. |
| * |
| * This is usable whether or not caching is enabled. |
| */ |
| int netfs_read_folio(struct file *file, struct folio *folio) |
| { |
| struct address_space *mapping = folio->mapping; |
| struct netfs_io_request *rreq; |
| struct netfs_inode *ctx = netfs_inode(mapping->host); |
| struct folio *sink = NULL; |
| int ret; |
| |
| _enter("%lx", folio->index); |
| |
| rreq = netfs_alloc_request(mapping, file, |
| folio_pos(folio), folio_size(folio), |
| NETFS_READPAGE); |
| if (IS_ERR(rreq)) { |
| ret = PTR_ERR(rreq); |
| goto alloc_error; |
| } |
| |
| ret = netfs_begin_cache_read(rreq, ctx); |
| if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) |
| goto discard; |
| |
| netfs_stat(&netfs_n_rh_read_folio); |
| trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage); |
| |
| /* Set up the output buffer */ |
| if (folio_test_dirty(folio)) { |
| /* Handle someone trying to read from an unflushed streaming |
| * write. We fiddle the buffer so that a gap at the beginning |
| * and/or a gap at the end get copied to, but the middle is |
| * discarded. |
| */ |
| struct netfs_folio *finfo = netfs_folio_info(folio); |
| struct bio_vec *bvec; |
| unsigned int from = finfo->dirty_offset; |
| unsigned int to = from + finfo->dirty_len; |
| unsigned int off = 0, i = 0; |
| size_t flen = folio_size(folio); |
| size_t nr_bvec = flen / PAGE_SIZE + 2; |
| size_t part; |
| |
| ret = -ENOMEM; |
| bvec = kmalloc_array(nr_bvec, sizeof(*bvec), GFP_KERNEL); |
| if (!bvec) |
| goto discard; |
| |
| sink = folio_alloc(GFP_KERNEL, 0); |
| if (!sink) |
| goto discard; |
| |
| trace_netfs_folio(folio, netfs_folio_trace_read_gaps); |
| |
| rreq->direct_bv = bvec; |
| rreq->direct_bv_count = nr_bvec; |
| if (from > 0) { |
| bvec_set_folio(&bvec[i++], folio, from, 0); |
| off = from; |
| } |
| while (off < to) { |
| part = min_t(size_t, to - off, PAGE_SIZE); |
| bvec_set_folio(&bvec[i++], sink, part, 0); |
| off += part; |
| } |
| if (to < flen) |
| bvec_set_folio(&bvec[i++], folio, flen - to, to); |
| iov_iter_bvec(&rreq->iter, ITER_DEST, bvec, i, rreq->len); |
| } else { |
| iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages, |
| rreq->start, rreq->len); |
| } |
| |
| ret = netfs_begin_read(rreq, true); |
| if (sink) |
| folio_put(sink); |
| netfs_put_request(rreq, false, netfs_rreq_trace_put_return); |
| return ret < 0 ? ret : 0; |
| |
| discard: |
| netfs_put_request(rreq, false, netfs_rreq_trace_put_discard); |
| alloc_error: |
| folio_unlock(folio); |
| return ret; |
| } |
| EXPORT_SYMBOL(netfs_read_folio); |
| |
| /* |
| * Prepare a folio for writing without reading first |
| * @folio: The folio being prepared |
| * @pos: starting position for the write |
| * @len: length of write |
| * @always_fill: T if the folio should always be completely filled/cleared |
| * |
| * In some cases, write_begin doesn't need to read at all: |
| * - full folio write |
| * - write that lies in a folio that is completely beyond EOF |
| * - write that covers the folio from start to EOF or beyond it |
| * |
| * If any of these criteria are met, then zero out the unwritten parts |
| * of the folio and return true. Otherwise, return false. |
| */ |
| static bool netfs_skip_folio_read(struct folio *folio, loff_t pos, size_t len, |
| bool always_fill) |
| { |
| struct inode *inode = folio_inode(folio); |
| loff_t i_size = i_size_read(inode); |
| size_t offset = offset_in_folio(folio, pos); |
| size_t plen = folio_size(folio); |
| |
| if (unlikely(always_fill)) { |
| if (pos - offset + len <= i_size) |
| return false; /* Page entirely before EOF */ |
| zero_user_segment(&folio->page, 0, plen); |
| folio_mark_uptodate(folio); |
| return true; |
| } |
| |
| /* Full folio write */ |
| if (offset == 0 && len >= plen) |
| return true; |
| |
| /* Page entirely beyond the end of the file */ |
| if (pos - offset >= i_size) |
| goto zero_out; |
| |
| /* Write that covers from the start of the folio to EOF or beyond */ |
| if (offset == 0 && (pos + len) >= i_size) |
| goto zero_out; |
| |
| return false; |
| zero_out: |
| zero_user_segments(&folio->page, 0, offset, offset + len, plen); |
| return true; |
| } |
| |
| /** |
| * netfs_write_begin - Helper to prepare for writing [DEPRECATED] |
| * @ctx: The netfs context |
| * @file: The file to read from |
| * @mapping: The mapping to read from |
| * @pos: File position at which the write will begin |
| * @len: The length of the write (may extend beyond the end of the folio chosen) |
| * @_folio: Where to put the resultant folio |
| * @_fsdata: Place for the netfs to store a cookie |
| * |
| * Pre-read data for a write-begin request by drawing data from the cache if |
| * possible, or the netfs if not. Space beyond the EOF is zero-filled. |
| * Multiple I/O requests from different sources will get munged together. If |
| * necessary, the readahead window can be expanded in either direction to a |
| * more convenient alighment for RPC efficiency or to make storage in the cache |
| * feasible. |
| * |
| * The calling netfs must provide a table of operations, only one of which, |
| * issue_op, is mandatory. |
| * |
| * The check_write_begin() operation can be provided to check for and flush |
| * conflicting writes once the folio is grabbed and locked. It is passed a |
| * pointer to the fsdata cookie that gets returned to the VM to be passed to |
| * write_end. It is permitted to sleep. It should return 0 if the request |
| * should go ahead or it may return an error. It may also unlock and put the |
| * folio, provided it sets ``*foliop`` to NULL, in which case a return of 0 |
| * will cause the folio to be re-got and the process to be retried. |
| * |
| * The calling netfs must initialise a netfs context contiguous to the vfs |
| * inode before calling this. |
| * |
| * This is usable whether or not caching is enabled. |
| * |
| * Note that this should be considered deprecated and netfs_perform_write() |
| * used instead. |
| */ |
| int netfs_write_begin(struct netfs_inode *ctx, |
| struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned int len, struct folio **_folio, |
| void **_fsdata) |
| { |
| struct netfs_io_request *rreq; |
| struct folio *folio; |
| pgoff_t index = pos >> PAGE_SHIFT; |
| int ret; |
| |
| DEFINE_READAHEAD(ractl, file, NULL, mapping, index); |
| |
| retry: |
| folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN, |
| mapping_gfp_mask(mapping)); |
| if (IS_ERR(folio)) |
| return PTR_ERR(folio); |
| |
| if (ctx->ops->check_write_begin) { |
| /* Allow the netfs (eg. ceph) to flush conflicts. */ |
| ret = ctx->ops->check_write_begin(file, pos, len, &folio, _fsdata); |
| if (ret < 0) { |
| trace_netfs_failure(NULL, NULL, ret, netfs_fail_check_write_begin); |
| goto error; |
| } |
| if (!folio) |
| goto retry; |
| } |
| |
| if (folio_test_uptodate(folio)) |
| goto have_folio; |
| |
| /* If the page is beyond the EOF, we want to clear it - unless it's |
| * within the cache granule containing the EOF, in which case we need |
| * to preload the granule. |
| */ |
| if (!netfs_is_cache_enabled(ctx) && |
| netfs_skip_folio_read(folio, pos, len, false)) { |
| netfs_stat(&netfs_n_rh_write_zskip); |
| goto have_folio_no_wait; |
| } |
| |
| rreq = netfs_alloc_request(mapping, file, |
| folio_pos(folio), folio_size(folio), |
| NETFS_READ_FOR_WRITE); |
| if (IS_ERR(rreq)) { |
| ret = PTR_ERR(rreq); |
| goto error; |
| } |
| rreq->no_unlock_folio = folio->index; |
| __set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags); |
| |
| ret = netfs_begin_cache_read(rreq, ctx); |
| if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) |
| goto error_put; |
| |
| netfs_stat(&netfs_n_rh_write_begin); |
| trace_netfs_read(rreq, pos, len, netfs_read_trace_write_begin); |
| |
| /* Expand the request to meet caching requirements and download |
| * preferences. |
| */ |
| ractl._nr_pages = folio_nr_pages(folio); |
| netfs_rreq_expand(rreq, &ractl); |
| |
| /* Set up the output buffer */ |
| iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages, |
| rreq->start, rreq->len); |
| |
| /* We hold the folio locks, so we can drop the references */ |
| folio_get(folio); |
| while (readahead_folio(&ractl)) |
| ; |
| |
| ret = netfs_begin_read(rreq, true); |
| if (ret < 0) |
| goto error; |
| netfs_put_request(rreq, false, netfs_rreq_trace_put_return); |
| |
| have_folio: |
| ret = folio_wait_private_2_killable(folio); |
| if (ret < 0) |
| goto error; |
| have_folio_no_wait: |
| *_folio = folio; |
| _leave(" = 0"); |
| return 0; |
| |
| error_put: |
| netfs_put_request(rreq, false, netfs_rreq_trace_put_failed); |
| error: |
| if (folio) { |
| folio_unlock(folio); |
| folio_put(folio); |
| } |
| _leave(" = %d", ret); |
| return ret; |
| } |
| EXPORT_SYMBOL(netfs_write_begin); |
| |
| /* |
| * Preload the data into a page we're proposing to write into. |
| */ |
| int netfs_prefetch_for_write(struct file *file, struct folio *folio, |
| size_t offset, size_t len) |
| { |
| struct netfs_io_request *rreq; |
| struct address_space *mapping = folio->mapping; |
| struct netfs_inode *ctx = netfs_inode(mapping->host); |
| unsigned long long start = folio_pos(folio); |
| size_t flen = folio_size(folio); |
| int ret; |
| |
| _enter("%zx @%llx", flen, start); |
| |
| ret = -ENOMEM; |
| |
| rreq = netfs_alloc_request(mapping, file, start, flen, |
| NETFS_READ_FOR_WRITE); |
| if (IS_ERR(rreq)) { |
| ret = PTR_ERR(rreq); |
| goto error; |
| } |
| |
| rreq->no_unlock_folio = folio->index; |
| __set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags); |
| ret = netfs_begin_cache_read(rreq, ctx); |
| if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) |
| goto error_put; |
| |
| netfs_stat(&netfs_n_rh_write_begin); |
| trace_netfs_read(rreq, start, flen, netfs_read_trace_prefetch_for_write); |
| |
| /* Set up the output buffer */ |
| iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages, |
| rreq->start, rreq->len); |
| |
| ret = netfs_begin_read(rreq, true); |
| netfs_put_request(rreq, false, netfs_rreq_trace_put_return); |
| return ret; |
| |
| error_put: |
| netfs_put_request(rreq, false, netfs_rreq_trace_put_discard); |
| error: |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /** |
| * netfs_buffered_read_iter - Filesystem buffered I/O read routine |
| * @iocb: kernel I/O control block |
| * @iter: destination for the data read |
| * |
| * This is the ->read_iter() routine for all filesystems that can use the page |
| * cache directly. |
| * |
| * The IOCB_NOWAIT flag in iocb->ki_flags indicates that -EAGAIN shall be |
| * returned when no data can be read without waiting for I/O requests to |
| * complete; it doesn't prevent readahead. |
| * |
| * The IOCB_NOIO flag in iocb->ki_flags indicates that no new I/O requests |
| * shall be made for the read or for readahead. When no data can be read, |
| * -EAGAIN shall be returned. When readahead would be triggered, a partial, |
| * possibly empty read shall be returned. |
| * |
| * Return: |
| * * number of bytes copied, even for partial reads |
| * * negative error code (or 0 if IOCB_NOIO) if nothing was read |
| */ |
| ssize_t netfs_buffered_read_iter(struct kiocb *iocb, struct iov_iter *iter) |
| { |
| struct inode *inode = file_inode(iocb->ki_filp); |
| struct netfs_inode *ictx = netfs_inode(inode); |
| ssize_t ret; |
| |
| if (WARN_ON_ONCE((iocb->ki_flags & IOCB_DIRECT) || |
| test_bit(NETFS_ICTX_UNBUFFERED, &ictx->flags))) |
| return -EINVAL; |
| |
| ret = netfs_start_io_read(inode); |
| if (ret == 0) { |
| ret = filemap_read(iocb, iter, 0); |
| netfs_end_io_read(inode); |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL(netfs_buffered_read_iter); |
| |
| /** |
| * netfs_file_read_iter - Generic filesystem read routine |
| * @iocb: kernel I/O control block |
| * @iter: destination for the data read |
| * |
| * This is the ->read_iter() routine for all filesystems that can use the page |
| * cache directly. |
| * |
| * The IOCB_NOWAIT flag in iocb->ki_flags indicates that -EAGAIN shall be |
| * returned when no data can be read without waiting for I/O requests to |
| * complete; it doesn't prevent readahead. |
| * |
| * The IOCB_NOIO flag in iocb->ki_flags indicates that no new I/O requests |
| * shall be made for the read or for readahead. When no data can be read, |
| * -EAGAIN shall be returned. When readahead would be triggered, a partial, |
| * possibly empty read shall be returned. |
| * |
| * Return: |
| * * number of bytes copied, even for partial reads |
| * * negative error code (or 0 if IOCB_NOIO) if nothing was read |
| */ |
| ssize_t netfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) |
| { |
| struct netfs_inode *ictx = netfs_inode(iocb->ki_filp->f_mapping->host); |
| |
| if ((iocb->ki_flags & IOCB_DIRECT) || |
| test_bit(NETFS_ICTX_UNBUFFERED, &ictx->flags)) |
| return netfs_unbuffered_read_iter(iocb, iter); |
| |
| return netfs_buffered_read_iter(iocb, iter); |
| } |
| EXPORT_SYMBOL(netfs_file_read_iter); |