From 9fffa4e9b3b158f63334e603e610da7d529a0f9a Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 27 Sep 2024 09:08:42 +0100 Subject: netfs: Advance iterator correctly rather than jumping it In netfs_write_folio(), use iov_iter_advance() to advance the folio as we split bits of it off to subrequests rather than manually jumping the ->iov_offset value around. This becomes more problematic when we use a bounce buffer made out of single-page folios to cover a multipage pagecache folio. Signed-off-by: David Howells Link: https://lore.kernel.org/r/2238548.1727424522@warthog.procyon.org.uk cc: Jeff Layton cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/write_issue.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'fs/netfs') diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c index 04e66d587f77..f9761d11791d 100644 --- a/fs/netfs/write_issue.c +++ b/fs/netfs/write_issue.c @@ -307,6 +307,7 @@ static int netfs_write_folio(struct netfs_io_request *wreq, struct netfs_io_stream *stream; struct netfs_group *fgroup; /* TODO: Use this with ceph */ struct netfs_folio *finfo; + size_t iter_off = 0; size_t fsize = folio_size(folio), flen = fsize, foff = 0; loff_t fpos = folio_pos(folio), i_size; bool to_eof = false, streamw = false; @@ -462,7 +463,12 @@ static int netfs_write_folio(struct netfs_io_request *wreq, if (choose_s < 0) break; stream = &wreq->io_streams[choose_s]; - wreq->io_iter.iov_offset = stream->submit_off; + + /* Advance the iterator(s). */ + if (stream->submit_off > iter_off) { + iov_iter_advance(&wreq->io_iter, stream->submit_off - iter_off); + iter_off = stream->submit_off; + } atomic64_set(&wreq->issued_to, fpos + stream->submit_off); stream->submit_extendable_to = fsize - stream->submit_off; @@ -477,8 +483,8 @@ static int netfs_write_folio(struct netfs_io_request *wreq, debug = true; } - wreq->io_iter.iov_offset = 0; - iov_iter_advance(&wreq->io_iter, fsize); + if (fsize > iter_off) + iov_iter_advance(&wreq->io_iter, fsize - iter_off); atomic64_set(&wreq->issued_to, fpos + fsize); if (!debug) -- cgit v1.2.3 From c6a90fe7f080d71271b723490454cfda1f81e4b0 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Sat, 5 Oct 2024 19:23:04 +0100 Subject: netfs: Fix a few minor bugs in netfs_page_mkwrite() We can't return with VM_FAULT_SIGBUS | VM_FAULT_LOCKED; the core code will not unlock the folio in this instance. Introduce a new "unlock" error exit to handle this case. Use it to handle the "folio is truncated" check, and change the "writeback interrupted by a fatal signal" to do a NOPAGE exit instead of letting the core code install the folio currently under writeback before killing the process. Signed-off-by: Matthew Wilcox (Oracle) Link: https://lore.kernel.org/r/20241005182307.3190401-3-willy@infradead.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_write.c | 27 +++++++++++++-------------- 1 file changed, 13 insertions(+), 14 deletions(-) (limited to 'fs/netfs') diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index b3910dfcb56d..ff2814da88b1 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -491,7 +491,9 @@ EXPORT_SYMBOL(netfs_file_write_iter); /* * Notification that a previously read-only page is about to become writable. - * Note that the caller indicates a single page of a multipage folio. + * The caller indicates the precise page that needs to be written to, but + * we only track group on a per-folio basis, so we block more often than + * we might otherwise. */ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group) { @@ -501,7 +503,7 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr struct address_space *mapping = file->f_mapping; struct inode *inode = file_inode(file); struct netfs_inode *ictx = netfs_inode(inode); - vm_fault_t ret = VM_FAULT_RETRY; + vm_fault_t ret = VM_FAULT_NOPAGE; int err; _enter("%lx", folio->index); @@ -510,21 +512,15 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr if (folio_lock_killable(folio) < 0) goto out; - if (folio->mapping != mapping) { - folio_unlock(folio); - ret = VM_FAULT_NOPAGE; - goto out; - } - - if (folio_wait_writeback_killable(folio)) { - ret = VM_FAULT_LOCKED; - goto out; - } + if (folio->mapping != mapping) + goto unlock; + if (folio_wait_writeback_killable(folio) < 0) + goto unlock; /* Can we see a streaming write here? */ if (WARN_ON(!folio_test_uptodate(folio))) { - ret = VM_FAULT_SIGBUS | VM_FAULT_LOCKED; - goto out; + ret = VM_FAULT_SIGBUS; + goto unlock; } group = netfs_folio_group(folio); @@ -559,5 +555,8 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr out: sb_end_pagefault(inode->i_sb); return ret; +unlock: + folio_unlock(folio); + goto out; } EXPORT_SYMBOL(netfs_page_mkwrite); -- cgit v1.2.3 From e995e8b600260cff3cfaf2607a62be8bdc4aa9c7 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Sat, 5 Oct 2024 19:23:05 +0100 Subject: netfs: Remove unnecessary references to pages These places should all use folios instead of pages. Signed-off-by: Matthew Wilcox (Oracle) Link: https://lore.kernel.org/r/20241005182307.3190401-4-willy@infradead.org Signed-off-by: Christian Brauner --- fs/netfs/buffered_read.c | 8 ++++---- fs/netfs/buffered_write.c | 14 +++++++------- 2 files changed, 11 insertions(+), 11 deletions(-) (limited to 'fs/netfs') diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index c40e226053cc..17aaec00002b 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -646,7 +646,7 @@ static bool netfs_skip_folio_read(struct folio *folio, loff_t pos, size_t len, if (unlikely(always_fill)) { if (pos - offset + len <= i_size) return false; /* Page entirely before EOF */ - zero_user_segment(&folio->page, 0, plen); + folio_zero_segment(folio, 0, plen); folio_mark_uptodate(folio); return true; } @@ -665,7 +665,7 @@ static bool netfs_skip_folio_read(struct folio *folio, loff_t pos, size_t len, return false; zero_out: - zero_user_segments(&folio->page, 0, offset, offset + len, plen); + folio_zero_segments(folio, 0, offset, offset + len, plen); return true; } @@ -732,7 +732,7 @@ retry: if (folio_test_uptodate(folio)) goto have_folio; - /* If the page is beyond the EOF, we want to clear it - unless it's + /* If the folio 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. */ @@ -792,7 +792,7 @@ error: EXPORT_SYMBOL(netfs_write_begin); /* - * Preload the data into a page we're proposing to write into. + * Preload the data into a folio we're proposing to write into. */ int netfs_prefetch_for_write(struct file *file, struct folio *folio, size_t offset, size_t len) diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index ff2814da88b1..b4826360a411 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -83,13 +83,13 @@ static void netfs_update_i_size(struct netfs_inode *ctx, struct inode *inode, * 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). + * @netfs_group: Grouping for dirty folios (eg. ceph snaps). * - * Copy data into pagecache pages attached to the inode specified by @iocb. + * Copy data into pagecache folios 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 + * Dirty folios are tagged with a netfs_folio struct if they're not up to date + * to indicate the range modified. Dirty folios may also be tagged with a * netfs-specific grouping such that data from an old group gets flushed before * a new one is started. */ @@ -223,11 +223,11 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, * we try to read it. */ if (fpos >= ctx->zero_point) { - zero_user_segment(&folio->page, 0, offset); + folio_zero_segment(folio, 0, offset); copied = copy_folio_from_iter_atomic(folio, offset, part, iter); if (unlikely(copied == 0)) goto copy_failed; - zero_user_segment(&folio->page, offset + copied, flen); + folio_zero_segment(folio, offset + copied, flen); __netfs_set_group(folio, netfs_group); folio_mark_uptodate(folio); trace_netfs_folio(folio, netfs_modify_and_clear); @@ -407,7 +407,7 @@ EXPORT_SYMBOL(netfs_perform_write); * netfs_buffered_write_iter_locked - write data to a file * @iocb: IO state structure (file, offset, etc.) * @from: iov_iter with data to write - * @netfs_group: Grouping for dirty pages (eg. ceph snaps). + * @netfs_group: Grouping for dirty folios (eg. ceph snaps). * * This function does all the work needed for actually writing data to a * file. It does all basic checks, removes SUID from the file, updates -- cgit v1.2.3