From 4498a8eccc97de3d65f876b6fdeddb439ef73abc Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 20 Nov 2023 17:09:47 +0000 Subject: netfs, fscache: Remove ->begin_cache_operation Remove ->begin_cache_operation() in favour of just calling fscache directly. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: Christian Brauner cc: linux-fsdevel@vger.kernel.org cc: linux-cachefs@redhat.com --- fs/netfs/buffered_read.c | 33 ++++++++++++++++++--------------- 1 file changed, 18 insertions(+), 15 deletions(-) (limited to 'fs/netfs/buffered_read.c') diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 2cd3ccf4c439..d39d0ffe75d2 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -147,6 +147,15 @@ static void netfs_rreq_expand(struct netfs_io_request *rreq, } } +/* + * 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 @@ -180,11 +189,9 @@ void netfs_readahead(struct readahead_control *ractl) if (IS_ERR(rreq)) return; - if (ctx->ops->begin_cache_operation) { - ret = ctx->ops->begin_cache_operation(rreq); - if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) - goto cleanup_free; - } + 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), @@ -238,11 +245,9 @@ int netfs_read_folio(struct file *file, struct folio *folio) goto alloc_error; } - if (ctx->ops->begin_cache_operation) { - ret = ctx->ops->begin_cache_operation(rreq); - if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) - goto discard; - } + ret = netfs_begin_cache_read(rreq, ctx); + if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) + goto discard; netfs_stat(&netfs_n_rh_readpage); trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage); @@ -390,11 +395,9 @@ retry: rreq->no_unlock_folio = folio_index(folio); __set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags); - if (ctx->ops->begin_cache_operation) { - ret = ctx->ops->begin_cache_operation(rreq); - if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS) - goto error_put; - } + 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); -- cgit v1.2.3 From 92b6cc5d1e7cbe569f00e9c1249ac8214fd5e2d2 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 26 Sep 2023 17:42:26 +0100 Subject: netfs: Add iov_iters to (sub)requests to describe various buffers Add three iov_iter structs: (1) Add an iov_iter (->iter) to the I/O request to describe the unencrypted-side buffer. (2) Add an iov_iter (->io_iter) to the I/O request to describe the encrypted-side I/O buffer. This may be a different size to the buffer in (1). (3) Add an iov_iter (->io_iter) to the I/O subrequest to describe the part of the I/O buffer for that subrequest. This will allow future patches to point to a bounce buffer instead for purposes of handling oversize writes, decryption (where we want to save the encrypted data to the cache) and decompression. These iov_iters persist for the lifetime of the (sub)request, and so can be accessed multiple times without worrying about them being deallocated upon return to the caller. The network filesystem must appropriately advance the iterator before terminating the request. Signed-off-by: David Howells cc: Jeff Layton cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/afs/file.c | 6 +---- fs/netfs/buffered_read.c | 13 +++++++++ fs/netfs/io.c | 69 +++++++++++++++++++++++++++++++++++------------- include/linux/netfs.h | 3 +++ 4 files changed, 67 insertions(+), 24 deletions(-) (limited to 'fs/netfs/buffered_read.c') diff --git a/fs/afs/file.c b/fs/afs/file.c index d152ba451f0e..3403bb792deb 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -323,11 +323,7 @@ static void afs_issue_read(struct netfs_io_subrequest *subreq) fsreq->len = subreq->len - subreq->transferred; fsreq->key = key_get(subreq->rreq->netfs_priv); fsreq->vnode = vnode; - fsreq->iter = &fsreq->def_iter; - - iov_iter_xarray(&fsreq->def_iter, ITER_DEST, - &fsreq->vnode->netfs.inode.i_mapping->i_pages, - fsreq->pos, fsreq->len); + fsreq->iter = &subreq->io_iter; afs_fetch_data(fsreq->vnode, fsreq); afs_put_read(fsreq); diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index d39d0ffe75d2..751556faa70b 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -199,6 +199,10 @@ void netfs_readahead(struct readahead_control *ractl) 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(). */ @@ -251,6 +255,11 @@ int netfs_read_folio(struct file *file, struct folio *folio) netfs_stat(&netfs_n_rh_readpage); trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage); + + /* Set up the output buffer */ + iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages, + rreq->start, rreq->len); + return netfs_begin_read(rreq, true); discard: @@ -408,6 +417,10 @@ retry: 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)) diff --git a/fs/netfs/io.c b/fs/netfs/io.c index 7f753380e047..e9d408e211b8 100644 --- a/fs/netfs/io.c +++ b/fs/netfs/io.c @@ -21,12 +21,7 @@ */ static void netfs_clear_unread(struct netfs_io_subrequest *subreq) { - struct iov_iter iter; - - iov_iter_xarray(&iter, ITER_DEST, &subreq->rreq->mapping->i_pages, - subreq->start + subreq->transferred, - subreq->len - subreq->transferred); - iov_iter_zero(iov_iter_count(&iter), &iter); + iov_iter_zero(iov_iter_count(&subreq->io_iter), &subreq->io_iter); } static void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error, @@ -46,14 +41,9 @@ static void netfs_read_from_cache(struct netfs_io_request *rreq, enum netfs_read_from_hole read_hole) { struct netfs_cache_resources *cres = &rreq->cache_resources; - struct iov_iter iter; netfs_stat(&netfs_n_rh_read); - iov_iter_xarray(&iter, ITER_DEST, &rreq->mapping->i_pages, - subreq->start + subreq->transferred, - subreq->len - subreq->transferred); - - cres->ops->read(cres, subreq->start, &iter, read_hole, + cres->ops->read(cres, subreq->start, &subreq->io_iter, read_hole, netfs_cache_read_terminated, subreq); } @@ -88,6 +78,11 @@ static void netfs_read_from_server(struct netfs_io_request *rreq, struct netfs_io_subrequest *subreq) { netfs_stat(&netfs_n_rh_download); + if (iov_iter_count(&subreq->io_iter) != subreq->len - subreq->transferred) + pr_warn("R=%08x[%u] ITER PRE-MISMATCH %zx != %zx-%zx %lx\n", + rreq->debug_id, subreq->debug_index, + iov_iter_count(&subreq->io_iter), subreq->len, + subreq->transferred, subreq->flags); rreq->netfs_ops->issue_read(subreq); } @@ -259,6 +254,30 @@ static void netfs_rreq_short_read(struct netfs_io_request *rreq, netfs_read_from_server(rreq, subreq); } +/* + * Reset the subrequest iterator prior to resubmission. + */ +static void netfs_reset_subreq_iter(struct netfs_io_request *rreq, + struct netfs_io_subrequest *subreq) +{ + size_t remaining = subreq->len - subreq->transferred; + size_t count = iov_iter_count(&subreq->io_iter); + + if (count == remaining) + return; + + _debug("R=%08x[%u] ITER RESUB-MISMATCH %zx != %zx-%zx-%llx %x\n", + rreq->debug_id, subreq->debug_index, + iov_iter_count(&subreq->io_iter), subreq->transferred, + subreq->len, rreq->i_size, + subreq->io_iter.iter_type); + + if (count < remaining) + iov_iter_revert(&subreq->io_iter, remaining - count); + else + iov_iter_advance(&subreq->io_iter, count - remaining); +} + /* * Resubmit any short or failed operations. Returns true if we got the rreq * ref back. @@ -287,6 +306,7 @@ static bool netfs_rreq_perform_resubmissions(struct netfs_io_request *rreq) trace_netfs_sreq(subreq, netfs_sreq_trace_download_instead); netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit); atomic_inc(&rreq->nr_outstanding); + netfs_reset_subreq_iter(rreq, subreq); netfs_read_from_server(rreq, subreq); } else if (test_bit(NETFS_SREQ_SHORT_IO, &subreq->flags)) { netfs_rreq_short_read(rreq, subreq); @@ -399,9 +419,9 @@ void netfs_subreq_terminated(struct netfs_io_subrequest *subreq, struct netfs_io_request *rreq = subreq->rreq; int u; - _enter("[%u]{%llx,%lx},%zd", - subreq->debug_index, subreq->start, subreq->flags, - transferred_or_error); + _enter("R=%x[%x]{%llx,%lx},%zd", + rreq->debug_id, subreq->debug_index, + subreq->start, subreq->flags, transferred_or_error); switch (subreq->source) { case NETFS_READ_FROM_CACHE: @@ -501,7 +521,8 @@ static enum netfs_io_source netfs_cache_prepare_read(struct netfs_io_subrequest */ static enum netfs_io_source netfs_rreq_prepare_read(struct netfs_io_request *rreq, - struct netfs_io_subrequest *subreq) + struct netfs_io_subrequest *subreq, + struct iov_iter *io_iter) { enum netfs_io_source source; @@ -528,9 +549,14 @@ netfs_rreq_prepare_read(struct netfs_io_request *rreq, } } - if (WARN_ON(subreq->len == 0)) + if (WARN_ON(subreq->len == 0)) { source = NETFS_INVALID_READ; + goto out; + } + subreq->io_iter = *io_iter; + iov_iter_truncate(&subreq->io_iter, subreq->len); + iov_iter_advance(io_iter, subreq->len); out: subreq->source = source; trace_netfs_sreq(subreq, netfs_sreq_trace_prepare); @@ -541,6 +567,7 @@ out: * Slice off a piece of a read request and submit an I/O request for it. */ static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq, + struct iov_iter *io_iter, unsigned int *_debug_index) { struct netfs_io_subrequest *subreq; @@ -565,7 +592,7 @@ static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq, * (the starts must coincide), in which case, we go around the loop * again and ask it to download the next piece. */ - source = netfs_rreq_prepare_read(rreq, subreq); + source = netfs_rreq_prepare_read(rreq, subreq, io_iter); if (source == NETFS_INVALID_READ) goto subreq_failed; @@ -603,6 +630,7 @@ subreq_failed: */ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) { + struct iov_iter io_iter; unsigned int debug_index = 0; int ret; @@ -615,6 +643,8 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) return -EIO; } + rreq->io_iter = rreq->iter; + INIT_WORK(&rreq->work, netfs_rreq_work); if (sync) @@ -624,8 +654,9 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) * want and submit each one. */ atomic_set(&rreq->nr_outstanding, 1); + io_iter = rreq->io_iter; do { - if (!netfs_rreq_submit_slice(rreq, &debug_index)) + if (!netfs_rreq_submit_slice(rreq, &io_iter, &debug_index)) break; } while (rreq->submitted < rreq->len); diff --git a/include/linux/netfs.h b/include/linux/netfs.h index fc6d9756a029..3da962e977f5 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -150,6 +150,7 @@ struct netfs_cache_resources { struct netfs_io_subrequest { struct netfs_io_request *rreq; /* Supervising I/O request */ struct list_head rreq_link; /* Link in rreq->subrequests */ + struct iov_iter io_iter; /* Iterator for this subrequest */ loff_t start; /* Where to start the I/O */ size_t len; /* Size of the I/O */ size_t transferred; /* Amount of data transferred */ @@ -186,6 +187,8 @@ struct netfs_io_request { struct netfs_cache_resources cache_resources; struct list_head proc_link; /* Link in netfs_iorequests */ struct list_head subrequests; /* Contributory I/O operations */ + struct iov_iter iter; /* Unencrypted-side iterator */ + struct iov_iter io_iter; /* I/O (Encrypted-side) iterator */ void *netfs_priv; /* Private data for the netfs */ unsigned int debug_id; atomic_t nr_outstanding; /* Number of ops in progress */ -- cgit v1.2.3 From 4fcccc38ebbdcff74494701c50a8e2fe4689837e Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 4 Oct 2023 16:15:48 +0100 Subject: netfs: Make the refcounting of netfs_begin_read() easier to use Make the refcounting of netfs_begin_read() easier to use by not eating the caller's ref on the netfs_io_request it's given. This makes it easier to use when we need to look in the request struct after. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/netfs/buffered_read.c | 6 +++++- fs/netfs/io.c | 28 +++++++++++++--------------- include/trace/events/netfs.h | 9 +++++---- 3 files changed, 23 insertions(+), 20 deletions(-) (limited to 'fs/netfs/buffered_read.c') diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 751556faa70b..6b9a44cafbac 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -210,6 +210,7 @@ void netfs_readahead(struct readahead_control *ractl) ; netfs_begin_read(rreq, false); + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); return; cleanup_free: @@ -260,7 +261,9 @@ int netfs_read_folio(struct file *file, struct folio *folio) iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages, rreq->start, rreq->len); - return netfs_begin_read(rreq, true); + ret = netfs_begin_read(rreq, true); + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); + return ret; discard: netfs_put_request(rreq, false, netfs_rreq_trace_put_discard); @@ -429,6 +432,7 @@ retry: 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_fscache_killable(folio); diff --git a/fs/netfs/io.c b/fs/netfs/io.c index e228bfb530ea..e83ef5835d25 100644 --- a/fs/netfs/io.c +++ b/fs/netfs/io.c @@ -362,6 +362,7 @@ again: netfs_rreq_unlock_folios(rreq); + trace_netfs_rreq(rreq, netfs_rreq_trace_wake_ip); clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &rreq->flags); wake_up_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS); @@ -657,7 +658,6 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) if (rreq->len == 0) { pr_err("Zero-sized read [R=%x]\n", rreq->debug_id); - netfs_put_request(rreq, false, netfs_rreq_trace_put_zero_len); return -EIO; } @@ -665,12 +665,10 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) INIT_WORK(&rreq->work, netfs_rreq_work); - if (sync) - netfs_get_request(rreq, netfs_rreq_trace_get_hold); - /* Chop the read into slices according to what the cache and the netfs * want and submit each one. */ + netfs_get_request(rreq, netfs_rreq_trace_get_for_outstanding); atomic_set(&rreq->nr_outstanding, 1); io_iter = rreq->io_iter; do { @@ -680,25 +678,25 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) } while (rreq->submitted < rreq->len); if (sync) { - /* Keep nr_outstanding incremented so that the ref always belongs to - * us, and the service code isn't punted off to a random thread pool to - * process. + /* Keep nr_outstanding incremented so that the ref always + * belongs to us, and the service code isn't punted off to a + * random thread pool to process. Note that this might start + * further work, such as writing to the cache. */ - for (;;) { - wait_var_event(&rreq->nr_outstanding, - atomic_read(&rreq->nr_outstanding) == 1); + wait_var_event(&rreq->nr_outstanding, + atomic_read(&rreq->nr_outstanding) == 1); + if (atomic_dec_and_test(&rreq->nr_outstanding)) netfs_rreq_assess(rreq, false); - if (!test_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags)) - break; - cond_resched(); - } + + trace_netfs_rreq(rreq, netfs_rreq_trace_wait_ip); + wait_on_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS, + TASK_UNINTERRUPTIBLE); ret = rreq->error; if (ret == 0 && rreq->submitted < rreq->len) { trace_netfs_failure(rreq, NULL, ret, netfs_fail_short_read); ret = -EIO; } - netfs_put_request(rreq, false, netfs_rreq_trace_put_hold); } else { /* If we decrement nr_outstanding to 0, the ref belongs to us. */ if (atomic_dec_and_test(&rreq->nr_outstanding)) diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index 4ea4e34d279f..6daadf2aac8a 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -34,7 +34,9 @@ EM(netfs_rreq_trace_free, "FREE ") \ EM(netfs_rreq_trace_resubmit, "RESUBMT") \ EM(netfs_rreq_trace_unlock, "UNLOCK ") \ - E_(netfs_rreq_trace_unmark, "UNMARK ") + EM(netfs_rreq_trace_unmark, "UNMARK ") \ + EM(netfs_rreq_trace_wait_ip, "WAIT-IP") \ + E_(netfs_rreq_trace_wake_ip, "WAKE-IP") #define netfs_sreq_sources \ EM(NETFS_FILL_WITH_ZEROES, "ZERO") \ @@ -65,14 +67,13 @@ E_(netfs_fail_prepare_write, "prep-write") #define netfs_rreq_ref_traces \ - EM(netfs_rreq_trace_get_hold, "GET HOLD ") \ + EM(netfs_rreq_trace_get_for_outstanding,"GET OUTSTND") \ EM(netfs_rreq_trace_get_subreq, "GET SUBREQ ") \ EM(netfs_rreq_trace_put_complete, "PUT COMPLT ") \ EM(netfs_rreq_trace_put_discard, "PUT DISCARD") \ EM(netfs_rreq_trace_put_failed, "PUT FAILED ") \ - EM(netfs_rreq_trace_put_hold, "PUT HOLD ") \ + EM(netfs_rreq_trace_put_return, "PUT RETURN ") \ EM(netfs_rreq_trace_put_subreq, "PUT SUBREQ ") \ - EM(netfs_rreq_trace_put_zero_len, "PUT ZEROLEN") \ E_(netfs_rreq_trace_new, "NEW ") #define netfs_sreq_ref_traces \ -- cgit v1.2.3 From c38f4e96e605f17990e871214e6ea1496bc4e65f Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 17 Jun 2021 13:09:21 +0100 Subject: netfs: Provide func to copy data to pagecache for buffered write Provide a netfs write helper, netfs_perform_write() to buffer data to be written in the pagecache and mark the modified folios dirty. It will perform "streaming writes" for folios that aren't currently resident, if possible, storing data in partially modified folios that are marked dirty, but not uptodate. It will also tag pages as belonging to fs-specific write groups if so directed by the filesystem. This is derived from generic_perform_write(), but doesn't use ->write_begin() and ->write_end(), having that logic rolled in instead. Signed-off-by: David Howells cc: Jeff Layton cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/netfs/Makefile | 1 + fs/netfs/buffered_read.c | 49 +++++++ fs/netfs/buffered_write.c | 330 +++++++++++++++++++++++++++++++++++++++++++ fs/netfs/internal.h | 2 + fs/netfs/io.c | 1 + include/linux/netfs.h | 5 + include/trace/events/netfs.h | 73 ++++++++++ 7 files changed, 461 insertions(+) create mode 100644 fs/netfs/buffered_write.c (limited to 'fs/netfs/buffered_read.c') diff --git a/fs/netfs/Makefile b/fs/netfs/Makefile index c69c6775b8ac..85d8333a1ed4 100644 --- a/fs/netfs/Makefile +++ b/fs/netfs/Makefile @@ -2,6 +2,7 @@ netfs-y := \ buffered_read.o \ + buffered_write.o \ io.o \ iterator.o \ locking.o \ diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 6b9a44cafbac..73a6e4d61f9d 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -63,6 +63,7 @@ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq) break; } if (!folio_started && test_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags)) { + trace_netfs_folio(folio, netfs_folio_trace_copy_to_cache); folio_start_fscache(folio); folio_started = true; } @@ -454,3 +455,51 @@ error: 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_file_mapping(folio); + 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(folio); + __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; +} diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c new file mode 100644 index 000000000000..6e7f06d9962d --- /dev/null +++ b/fs/netfs/buffered_write.c @@ -0,0 +1,330 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Network filesystem high-level write support. + * + * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include +#include +#include +#include +#include +#include "internal.h" + +/* + * Determined write method. Adjust netfs_folio_traces if this is changed. + */ +enum netfs_how_to_modify { + NETFS_FOLIO_IS_UPTODATE, /* Folio is uptodate already */ + NETFS_JUST_PREFETCH, /* We have to read the folio anyway */ + NETFS_WHOLE_FOLIO_MODIFY, /* We're going to overwrite the whole folio */ + NETFS_MODIFY_AND_CLEAR, /* We can assume there is no data to be downloaded. */ + NETFS_STREAMING_WRITE, /* Store incomplete data in non-uptodate page. */ + NETFS_STREAMING_WRITE_CONT, /* Continue streaming write. */ + NETFS_FLUSH_CONTENT, /* Flush incompatible content. */ +}; + +static void netfs_set_group(struct folio *folio, struct netfs_group *netfs_group) +{ + if (netfs_group && !folio_get_private(folio)) + folio_attach_private(folio, netfs_get_group(netfs_group)); +} + +/* + * Decide how we should modify a folio. We might be attempting to do + * write-streaming, in which case we don't want to a local RMW cycle if we can + * avoid it. If we're doing local caching or content crypto, we award that + * priority over avoiding RMW. If the file is open readably, then we also + * assume that we may want to read what we wrote. + */ +static enum netfs_how_to_modify netfs_how_to_modify(struct netfs_inode *ctx, + struct file *file, + struct folio *folio, + void *netfs_group, + size_t flen, + size_t offset, + size_t len, + bool maybe_trouble) +{ + struct netfs_folio *finfo = netfs_folio_info(folio); + loff_t pos = folio_file_pos(folio); + + _enter(""); + + if (netfs_folio_group(folio) != netfs_group) + return NETFS_FLUSH_CONTENT; + + if (folio_test_uptodate(folio)) + return NETFS_FOLIO_IS_UPTODATE; + + if (pos >= ctx->remote_i_size) + return NETFS_MODIFY_AND_CLEAR; + + if (!maybe_trouble && offset == 0 && len >= flen) + return NETFS_WHOLE_FOLIO_MODIFY; + + if (file->f_mode & FMODE_READ) + return NETFS_JUST_PREFETCH; + + if (netfs_is_cache_enabled(ctx)) + return NETFS_JUST_PREFETCH; + + if (!finfo) + return NETFS_STREAMING_WRITE; + + /* We can continue a streaming write only if it continues on from the + * previous. If it overlaps, we must flush lest we suffer a partial + * copy and disjoint dirty regions. + */ + if (offset == finfo->dirty_offset + finfo->dirty_len) + return NETFS_STREAMING_WRITE_CONT; + return NETFS_FLUSH_CONTENT; +} + +/* + * Grab a folio for writing and lock it. + */ +static struct folio *netfs_grab_folio_for_write(struct address_space *mapping, + loff_t pos, size_t part) +{ + pgoff_t index = pos / PAGE_SIZE; + + return __filemap_get_folio(mapping, index, FGP_WRITEBEGIN, + mapping_gfp_mask(mapping)); +} + +/** + * netfs_perform_write - Copy data into the pagecache. + * @iocb: The operation parameters + * @iter: The source buffer + * @netfs_group: Grouping for dirty pages (eg. ceph snaps). + * + * Copy data into pagecache pages attached to the inode specified by @iocb. + * The caller must hold appropriate inode locks. + * + * Dirty pages are tagged with a netfs_folio struct if they're not up to date + * to indicate the range modified. Dirty pages may also be tagged with a + * netfs-specific grouping such that data from an old group gets flushed before + * a new one is started. + */ +ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, + struct netfs_group *netfs_group) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file_inode(file); + struct address_space *mapping = inode->i_mapping; + struct netfs_inode *ctx = netfs_inode(inode); + struct netfs_folio *finfo; + struct folio *folio; + enum netfs_how_to_modify howto; + enum netfs_folio_trace trace; + unsigned int bdp_flags = (iocb->ki_flags & IOCB_SYNC) ? 0: BDP_ASYNC; + ssize_t written = 0, ret; + loff_t i_size, pos = iocb->ki_pos, from, to; + size_t max_chunk = PAGE_SIZE << MAX_PAGECACHE_ORDER; + bool maybe_trouble = false; + + do { + size_t flen; + size_t offset; /* Offset into pagecache folio */ + size_t part; /* Bytes to write to folio */ + size_t copied; /* Bytes copied from user */ + + ret = balance_dirty_pages_ratelimited_flags(mapping, bdp_flags); + if (unlikely(ret < 0)) + break; + + offset = pos & (max_chunk - 1); + part = min(max_chunk - offset, iov_iter_count(iter)); + + /* Bring in the user pages that we will copy from _first_ lest + * we hit a nasty deadlock on copying from the same page as + * we're writing to, without it being marked uptodate. + * + * Not only is this an optimisation, but it is also required to + * check that the address is actually valid, when atomic + * usercopies are used below. + * + * We rely on the page being held onto long enough by the LRU + * that we can grab it below if this causes it to be read. + */ + ret = -EFAULT; + if (unlikely(fault_in_iov_iter_readable(iter, part) == part)) + break; + + ret = -ENOMEM; + folio = netfs_grab_folio_for_write(mapping, pos, part); + if (!folio) + break; + + flen = folio_size(folio); + offset = pos & (flen - 1); + part = min_t(size_t, flen - offset, part); + + if (signal_pending(current)) { + ret = written ? -EINTR : -ERESTARTSYS; + goto error_folio_unlock; + } + + /* See if we need to prefetch the area we're going to modify. + * We need to do this before we get a lock on the folio in case + * there's more than one writer competing for the same cache + * block. + */ + howto = netfs_how_to_modify(ctx, file, folio, netfs_group, + flen, offset, part, maybe_trouble); + _debug("howto %u", howto); + switch (howto) { + case NETFS_JUST_PREFETCH: + ret = netfs_prefetch_for_write(file, folio, offset, part); + if (ret < 0) { + _debug("prefetch = %zd", ret); + goto error_folio_unlock; + } + break; + case NETFS_FOLIO_IS_UPTODATE: + case NETFS_WHOLE_FOLIO_MODIFY: + case NETFS_STREAMING_WRITE_CONT: + break; + case NETFS_MODIFY_AND_CLEAR: + zero_user_segment(&folio->page, 0, offset); + break; + case NETFS_STREAMING_WRITE: + ret = -EIO; + if (WARN_ON(folio_get_private(folio))) + goto error_folio_unlock; + break; + case NETFS_FLUSH_CONTENT: + trace_netfs_folio(folio, netfs_flush_content); + from = folio_pos(folio); + to = from + folio_size(folio) - 1; + folio_unlock(folio); + folio_put(folio); + ret = filemap_write_and_wait_range(mapping, from, to); + if (ret < 0) + goto error_folio_unlock; + continue; + } + + if (mapping_writably_mapped(mapping)) + flush_dcache_folio(folio); + + copied = copy_folio_from_iter_atomic(folio, offset, part, iter); + + flush_dcache_folio(folio); + + /* Deal with a (partially) failed copy */ + if (copied == 0) { + ret = -EFAULT; + goto error_folio_unlock; + } + + trace = (enum netfs_folio_trace)howto; + switch (howto) { + case NETFS_FOLIO_IS_UPTODATE: + case NETFS_JUST_PREFETCH: + netfs_set_group(folio, netfs_group); + break; + case NETFS_MODIFY_AND_CLEAR: + zero_user_segment(&folio->page, offset + copied, flen); + netfs_set_group(folio, netfs_group); + folio_mark_uptodate(folio); + break; + case NETFS_WHOLE_FOLIO_MODIFY: + if (unlikely(copied < part)) { + maybe_trouble = true; + iov_iter_revert(iter, copied); + copied = 0; + goto retry; + } + netfs_set_group(folio, netfs_group); + folio_mark_uptodate(folio); + break; + case NETFS_STREAMING_WRITE: + if (offset == 0 && copied == flen) { + netfs_set_group(folio, netfs_group); + folio_mark_uptodate(folio); + trace = netfs_streaming_filled_page; + break; + } + finfo = kzalloc(sizeof(*finfo), GFP_KERNEL); + if (!finfo) { + iov_iter_revert(iter, copied); + ret = -ENOMEM; + goto error_folio_unlock; + } + finfo->netfs_group = netfs_get_group(netfs_group); + finfo->dirty_offset = offset; + finfo->dirty_len = copied; + folio_attach_private(folio, (void *)((unsigned long)finfo | + NETFS_FOLIO_INFO)); + break; + case NETFS_STREAMING_WRITE_CONT: + finfo = netfs_folio_info(folio); + finfo->dirty_len += copied; + if (finfo->dirty_offset == 0 && finfo->dirty_len == flen) { + if (finfo->netfs_group) + folio_change_private(folio, finfo->netfs_group); + else + folio_detach_private(folio); + folio_mark_uptodate(folio); + kfree(finfo); + trace = netfs_streaming_cont_filled_page; + } + break; + default: + WARN(true, "Unexpected modify type %u ix=%lx\n", + howto, folio_index(folio)); + ret = -EIO; + goto error_folio_unlock; + } + + trace_netfs_folio(folio, trace); + + /* Update the inode size if we moved the EOF marker */ + i_size = i_size_read(inode); + pos += copied; + if (pos > i_size) { + if (ctx->ops->update_i_size) { + ctx->ops->update_i_size(inode, pos); + } else { + i_size_write(inode, pos); +#if IS_ENABLED(CONFIG_FSCACHE) + fscache_update_cookie(ctx->cache, NULL, &pos); +#endif + } + } + written += copied; + + folio_mark_dirty(folio); + retry: + folio_unlock(folio); + folio_put(folio); + folio = NULL; + + cond_resched(); + } while (iov_iter_count(iter)); + +out: + if (likely(written)) { + /* Flush and wait for a write that requires immediate synchronisation. */ + if (iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC)) { + _debug("dsync"); + ret = filemap_fdatawait_range(mapping, iocb->ki_pos, + iocb->ki_pos + written); + } + + iocb->ki_pos += written; + } + + _leave(" = %zd [%zd]", written, ret); + return written ? written : ret; + +error_folio_unlock: + folio_unlock(folio); + folio_put(folio); + goto out; +} +EXPORT_SYMBOL(netfs_perform_write); diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h index 0f20587f5a9b..17e4ea4456c7 100644 --- a/fs/netfs/internal.h +++ b/fs/netfs/internal.h @@ -23,6 +23,8 @@ * buffered_read.c */ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq); +int netfs_prefetch_for_write(struct file *file, struct folio *folio, + size_t offset, size_t len); /* * io.c diff --git a/fs/netfs/io.c b/fs/netfs/io.c index e83ef5835d25..774aef6ea4cb 100644 --- a/fs/netfs/io.c +++ b/fs/netfs/io.c @@ -125,6 +125,7 @@ static void netfs_rreq_unmark_after_write(struct netfs_io_request *rreq, if (have_unlocked && folio_index(folio) <= unlocked) continue; unlocked = folio_index(folio); + trace_netfs_folio(folio, netfs_folio_trace_end_copy); folio_end_fscache(folio); have_unlocked = true; } diff --git a/include/linux/netfs.h b/include/linux/netfs.h index 890a5d8b2299..70f578cf3715 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -367,6 +367,11 @@ struct netfs_cache_ops { loff_t *_data_start, size_t *_data_len); }; +/* High-level write API */ +ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, + struct netfs_group *netfs_group); + +/* Address operations API */ struct readahead_control; void netfs_readahead(struct readahead_control *); int netfs_read_folio(struct file *, struct folio *); diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index e03635172760..8308b81f36be 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -19,6 +19,7 @@ EM(netfs_read_trace_expanded, "EXPANDED ") \ EM(netfs_read_trace_readahead, "READAHEAD") \ EM(netfs_read_trace_readpage, "READPAGE ") \ + EM(netfs_read_trace_prefetch_for_write, "PREFETCHW") \ E_(netfs_read_trace_write_begin, "WRITEBEGN") #define netfs_write_traces \ @@ -100,6 +101,31 @@ EM(netfs_sreq_trace_put_work, "PUT WORK ") \ E_(netfs_sreq_trace_put_terminated, "PUT TERM ") +#define netfs_folio_traces \ + /* The first few correspond to enum netfs_how_to_modify */ \ + EM(netfs_folio_is_uptodate, "mod-uptodate") \ + EM(netfs_just_prefetch, "mod-prefetch") \ + EM(netfs_whole_folio_modify, "mod-whole-f") \ + EM(netfs_modify_and_clear, "mod-n-clear") \ + EM(netfs_streaming_write, "mod-streamw") \ + EM(netfs_streaming_write_cont, "mod-streamw+") \ + EM(netfs_flush_content, "flush") \ + EM(netfs_streaming_filled_page, "mod-streamw-f") \ + EM(netfs_streaming_cont_filled_page, "mod-streamw-f+") \ + /* The rest are for writeback */ \ + EM(netfs_folio_trace_clear, "clear") \ + EM(netfs_folio_trace_clear_s, "clear-s") \ + EM(netfs_folio_trace_clear_g, "clear-g") \ + EM(netfs_folio_trace_copy_to_cache, "copy") \ + EM(netfs_folio_trace_end_copy, "end-copy") \ + EM(netfs_folio_trace_kill, "kill") \ + EM(netfs_folio_trace_mkwrite, "mkwrite") \ + EM(netfs_folio_trace_mkwrite_plus, "mkwrite+") \ + EM(netfs_folio_trace_redirty, "redirty") \ + EM(netfs_folio_trace_redirtied, "redirtied") \ + EM(netfs_folio_trace_store, "store") \ + E_(netfs_folio_trace_store_plus, "store+") + #ifndef __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY #define __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY @@ -115,6 +141,7 @@ enum netfs_sreq_trace { netfs_sreq_traces } __mode(byte); enum netfs_failure { netfs_failures } __mode(byte); enum netfs_rreq_ref_trace { netfs_rreq_ref_traces } __mode(byte); enum netfs_sreq_ref_trace { netfs_sreq_ref_traces } __mode(byte); +enum netfs_folio_trace { netfs_folio_traces } __mode(byte); #endif @@ -135,6 +162,7 @@ netfs_sreq_traces; netfs_failures; netfs_rreq_ref_traces; netfs_sreq_ref_traces; +netfs_folio_traces; /* * Now redefine the EM() and E_() macros to map the enums to the strings that @@ -335,6 +363,51 @@ TRACE_EVENT(netfs_sreq_ref, __entry->ref) ); +TRACE_EVENT(netfs_folio, + TP_PROTO(struct folio *folio, enum netfs_folio_trace why), + + TP_ARGS(folio, why), + + TP_STRUCT__entry( + __field(ino_t, ino) + __field(pgoff_t, index) + __field(unsigned int, nr) + __field(enum netfs_folio_trace, why) + ), + + TP_fast_assign( + __entry->ino = folio->mapping->host->i_ino; + __entry->why = why; + __entry->index = folio_index(folio); + __entry->nr = folio_nr_pages(folio); + ), + + TP_printk("i=%05lx ix=%05lx-%05lx %s", + __entry->ino, __entry->index, __entry->index + __entry->nr - 1, + __print_symbolic(__entry->why, netfs_folio_traces)) + ); + +TRACE_EVENT(netfs_write_iter, + TP_PROTO(const struct kiocb *iocb, const struct iov_iter *from), + + TP_ARGS(iocb, from), + + TP_STRUCT__entry( + __field(unsigned long long, start ) + __field(size_t, len ) + __field(unsigned int, flags ) + ), + + TP_fast_assign( + __entry->start = iocb->ki_pos; + __entry->len = iov_iter_count(from); + __entry->flags = iocb->ki_flags; + ), + + TP_printk("WRITE-ITER s=%llx l=%zx f=%x", + __entry->start, __entry->len, __entry->flags) + ); + TRACE_EVENT(netfs_write, TP_PROTO(const struct netfs_io_request *wreq, enum netfs_write_trace what), -- cgit v1.2.3 From 7f84a7b9892d1c9429a6f5d6f67916c61b3fc183 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 2 Oct 2023 12:51:19 +0100 Subject: netfs: Make netfs_read_folio() handle streaming-write pages netfs_read_folio() needs to handle partially-valid pages that are marked dirty, but not uptodate in the event that someone tries to read a page was used to cache data by a streaming write. In such a case, make netfs_read_folio() set up a bvec iterator that points to the parts of the folio that need filling and to a sink page for the data that should be discarded and use that instead of i_pages as the iterator to be written to. This requires netfs_rreq_unlock_folios() to convert the page into a normal dirty uptodate page, getting rid of the partial write record and bumping the group pointer over to folio->private. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/netfs/buffered_read.c | 61 +++++++++++++++++++++++++++++++++++++++++--- include/trace/events/netfs.h | 2 ++ 2 files changed, 60 insertions(+), 3 deletions(-) (limited to 'fs/netfs/buffered_read.c') diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 73a6e4d61f9d..950f63fc156a 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -16,6 +16,7 @@ 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; @@ -87,6 +88,15 @@ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq) 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); } @@ -239,6 +249,7 @@ int netfs_read_folio(struct file *file, struct folio *folio) struct address_space *mapping = folio_file_mapping(folio); struct netfs_io_request *rreq; struct netfs_inode *ctx = netfs_inode(mapping->host); + struct folio *sink = NULL; int ret; _enter("%lx", folio_index(folio)); @@ -259,12 +270,56 @@ int netfs_read_folio(struct file *file, struct folio *folio) trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage); /* Set up the output buffer */ - iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages, - rreq->start, rreq->len); + 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; + return ret < 0 ? ret : 0; discard: netfs_put_request(rreq, false, netfs_rreq_trace_put_discard); diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index 8308b81f36be..082a5e717b58 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -118,9 +118,11 @@ EM(netfs_folio_trace_clear_g, "clear-g") \ EM(netfs_folio_trace_copy_to_cache, "copy") \ EM(netfs_folio_trace_end_copy, "end-copy") \ + EM(netfs_folio_trace_filled_gaps, "filled-gaps") \ EM(netfs_folio_trace_kill, "kill") \ EM(netfs_folio_trace_mkwrite, "mkwrite") \ EM(netfs_folio_trace_mkwrite_plus, "mkwrite+") \ + EM(netfs_folio_trace_read_gaps, "read-gaps") \ EM(netfs_folio_trace_redirty, "redirty") \ EM(netfs_folio_trace_redirtied, "redirtied") \ EM(netfs_folio_trace_store, "store") \ -- cgit v1.2.3 From 80645bd4aa33a5c325f11b8dc6b38b38410ad5c0 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 11 Oct 2023 09:29:43 +0100 Subject: netfs: Provide netfs_file_read_iter() Provide a top-level-ish function that can be pointed to directly by ->read_iter file op. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/netfs/buffered_read.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/netfs.h | 2 ++ 2 files changed, 75 insertions(+) (limited to 'fs/netfs/buffered_read.c') diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 950f63fc156a..a59e7b2edaac 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -558,3 +558,76 @@ 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); diff --git a/include/linux/netfs.h b/include/linux/netfs.h index d7f324c7c22a..19a41c437af3 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -378,6 +378,8 @@ struct netfs_cache_ops { /* High-level read API. */ ssize_t netfs_unbuffered_read_iter(struct kiocb *iocb, struct iov_iter *iter); +ssize_t netfs_buffered_read_iter(struct kiocb *iocb, struct iov_iter *iter); +ssize_t netfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter); /* High-level write API */ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, -- cgit v1.2.3 From 202bc57b675601bc07b5942369ecc16af64d1b95 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 9 Jan 2024 17:17:36 +0000 Subject: netfs: Don't use certain unnecessary folio_*() functions Filesystems should use folio->index and folio->mapping, instead of folio_index(folio), folio_mapping() and folio_file_mapping() since they know that it's in the pagecache. Change this automagically with: perl -p -i -e 's/folio_mapping[(]([^)]*)[)]/\1->mapping/g' fs/netfs/*.c perl -p -i -e 's/folio_file_mapping[(]([^)]*)[)]/\1->mapping/g' fs/netfs/*.c perl -p -i -e 's/folio_index[(]([^)]*)[)]/\1->index/g' fs/netfs/*.c Reported-by: Matthew Wilcox Signed-off-by: David Howells cc: Jeff Layton cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-cifs@vger.kernel.org cc: linux-erofs@lists.ozlabs.org cc: linux-fsdevel@vger.kernel.org --- fs/netfs/buffered_read.c | 12 ++++++------ fs/netfs/buffered_write.c | 10 +++++----- fs/netfs/io.c | 2 +- fs/netfs/misc.c | 2 +- 4 files changed, 13 insertions(+), 13 deletions(-) (limited to 'fs/netfs/buffered_read.c') diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index a59e7b2edaac..3298c29b5548 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -101,7 +101,7 @@ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq) } if (!test_bit(NETFS_RREQ_DONT_UNLOCK_FOLIOS, &rreq->flags)) { - if (folio_index(folio) == rreq->no_unlock_folio && + if (folio->index == rreq->no_unlock_folio && test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags)) _debug("no unlock"); else @@ -246,13 +246,13 @@ EXPORT_SYMBOL(netfs_readahead); */ int netfs_read_folio(struct file *file, struct folio *folio) { - struct address_space *mapping = folio_file_mapping(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(folio)); + _enter("%lx", folio->index); rreq = netfs_alloc_request(mapping, file, folio_file_pos(folio), folio_size(folio), @@ -460,7 +460,7 @@ retry: ret = PTR_ERR(rreq); goto error; } - rreq->no_unlock_folio = folio_index(folio); + rreq->no_unlock_folio = folio->index; __set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags); ret = netfs_begin_cache_read(rreq, ctx); @@ -518,7 +518,7 @@ 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_file_mapping(folio); + 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); @@ -535,7 +535,7 @@ int netfs_prefetch_for_write(struct file *file, struct folio *folio, goto error; } - rreq->no_unlock_folio = folio_index(folio); + 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) diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index 93dc76f34e39..e7f9ba6fb16b 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -343,7 +343,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, break; default: WARN(true, "Unexpected modify type %u ix=%lx\n", - howto, folio_index(folio)); + howto, folio->index); ret = -EIO; goto error_folio_unlock; } @@ -648,7 +648,7 @@ static void netfs_pages_written_back(struct netfs_io_request *wreq) xas_for_each(&xas, folio, last) { WARN(!folio_test_writeback(folio), "bad %zx @%llx page %lx %lx\n", - wreq->len, wreq->start, folio_index(folio), last); + wreq->len, wreq->start, folio->index, last); if ((finfo = netfs_folio_info(folio))) { /* Streaming writes cannot be redirtied whilst under @@ -795,7 +795,7 @@ static void netfs_extend_writeback(struct address_space *mapping, continue; if (xa_is_value(folio)) break; - if (folio_index(folio) != index) { + if (folio->index != index) { xas_reset(xas); break; } @@ -901,7 +901,7 @@ static ssize_t netfs_write_back_from_locked_folio(struct address_space *mapping, long count = wbc->nr_to_write; int ret; - _enter(",%lx,%llx-%llx,%u", folio_index(folio), start, end, caching); + _enter(",%lx,%llx-%llx,%u", folio->index, start, end, caching); wreq = netfs_alloc_request(mapping, NULL, start, folio_size(folio), NETFS_WRITEBACK); @@ -1047,7 +1047,7 @@ search_again: start = folio_pos(folio); /* May regress with THPs */ - _debug("wback %lx", folio_index(folio)); + _debug("wback %lx", folio->index); /* At this point we hold neither the i_pages lock nor the page lock: * the page may be truncated or invalidated (changing page->mapping to diff --git a/fs/netfs/io.c b/fs/netfs/io.c index 4309edf33862..e8ff1e61ce79 100644 --- a/fs/netfs/io.c +++ b/fs/netfs/io.c @@ -124,7 +124,7 @@ static void netfs_rreq_unmark_after_write(struct netfs_io_request *rreq, /* We might have multiple writes from the same huge * folio, but we mustn't unlock a folio more than once. */ - if (have_unlocked && folio_index(folio) <= unlocked) + if (have_unlocked && folio->index <= unlocked) continue; unlocked = folio_next_index(folio) - 1; trace_netfs_folio(folio, netfs_folio_trace_end_copy); diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c index 0e3af37fc924..90051ced8e2a 100644 --- a/fs/netfs/misc.c +++ b/fs/netfs/misc.c @@ -180,7 +180,7 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length) struct netfs_folio *finfo = NULL; size_t flen = folio_size(folio); - _enter("{%lx},%zx,%zx", folio_index(folio), offset, length); + _enter("{%lx},%zx,%zx", folio->index, offset, length); folio_wait_fscache(folio); -- cgit v1.2.3