From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9D8FB284690 for ; Thu, 27 Aug 2026 11:17:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787829467; cv=none; b=hfypHEt0nSAW8QFwxuVwSt2OG+WXhJ5p7mp4afP1D47weFNjijVCh9Sg1BnmmcEjrHI9JSMKfWwCJPuxluS5DOq7/NcNuY0h3HEi2bU8lg1QGrSPMtZgu3mazyVTnefajPLQu+vcyNuugwMGdJiW4liXeVqIUHX8sY+5fq4qZac= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787829467; c=relaxed/simple; bh=Uuvx2qkuQDSU5xx4en03ujADsE7yJzb5HqD0FcmA31o=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=QN/87T9r54DPrKgDW3Ef4M57as3QtjvQvLIv1Ks8jcojVuiMB/kBrkaN0S7BolmBT0Ks++r+kfRvs+C9S40Yvmd9fGHD5PRjM3L76vUFi9aaEh56bU+m7tRfCbQafH7lkATZB+d9ONCTNsd8nJL7bkYlPjg/RMwSfOedcW8qd+E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=N4VjvVhw; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="N4VjvVhw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F8201F000E9; Thu, 27 Aug 2026 11:17:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787829457; bh=I4Bt8kr0nNnrQ6UbfitFzZlShwAgxIrVJzbQud63VPQ=; h=Date:Cc:Subject:To:References:From:In-Reply-To; b=N4VjvVhwcBouu4O/kHvKoRJddKX/7L8jwl2GVWi23t+oHsbCQtX//AGoko/6ywFQN Dz62sUuWv1RaowDNtKhOAMu1vqaxzCungLVHrIp583j96LwmJWB9asxJ5EQFolYYUb LXXKDTh7mmoQBB9eZWkRL7w2flWGV9U0ET9VQZ6HEsSZu7niDS5YFB5OOWom1M+sE3 MlwYWNu8bxQnlNUbPCxPmL92zT89NJNcVJHnzuBPX9S2tCVVTcWiLdwDLJPJ2aRxop Z05aiMAdDtSpdbv6ob3zV+m7tgoMuCV89pdxL8QwMaCw0AmZxkhNJbDdOKvybqlkk8 9D5As3P7H/0Nw== Message-ID: <12ab1762-e635-42d6-ab0b-e3358e3b32c2@kernel.org> Date: Thu, 27 Aug 2026 19:17:33 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, Barry Song , Nanzhe Zhao , Juan Yescas , Dev Jain , linux-kernel@vger.kernel.org, David Hildenbrand , Bo Zhang , Kalesh Singh , Ryan Roberts , Pengfei Li Subject: Re: [PATCH 05/14] f2fs: support large folio writeback To: Nanzhe Zhao , linux-f2fs-devel@lists.sourceforge.net, Jaegeuk Kim References: <20260826082641.2007658-1-zhaonanzhe@xiaomi.com> <20260826082641.2007658-6-zhaonanzhe@xiaomi.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20260826082641.2007658-6-zhaonanzhe@xiaomi.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/26/26 16:26, Nanzhe Zhao wrote: > Large folio can contain multiple dirty ranges. > Add a folio-based writeback path for large-folio mapping files > and keep the legacy f2fs_write_cache_pages() path unchanged for > non large-folio mapping files. > > Signed-off-by: Nanzhe Zhao > --- > fs/f2fs/data.c | 404 ++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 398 insertions(+), 6 deletions(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index dff802725544..608d8ea8e607 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -358,6 +358,7 @@ static void f2fs_write_end_bio(struct bio *bio) > struct folio *folio = fi.folio; > unsigned int nr_pages = fi.length >> PAGE_SHIFT; > enum count_type type; > + bool finished = true; > > if (fscrypt_is_bounce_folio(folio)) { > struct folio *io_folio = folio; > @@ -388,11 +389,20 @@ static void f2fs_write_end_bio(struct bio *bio) > folio->index, NODE_TYPE_REGULAR, true); > f2fs_bug_on(sbi, folio->index != nid_of_node(folio)); > } > + if (f2fs_folio_has_ffs(folio)) { > + struct f2fs_folio_state *ffs = > + (struct f2fs_folio_state *)folio->private; > + > + finished = atomic_sub_and_test(nr_pages, > + &ffs->write_pages_pending); > + } > + > + while (nr_pages--) > + dec_page_count(sbi, type); > + > if (f2fs_in_warm_node_list(folio)) > f2fs_del_fsync_node_entry(sbi, folio); > > - dec_page_count(sbi, type); We should not relocate dec_page_count() above f2fs_in_warm_node_list() to avoid racing bugs. > - > /* > * we should access sbi before folio_end_writeback() to > * avoid racing w/ kill_f2fs_super() > @@ -401,8 +411,10 @@ static void f2fs_write_end_bio(struct bio *bio) > wq_has_sleeper(&sbi->cp_wait)) > wake_up(&sbi->cp_wait); > > - folio_clear_f2fs_gcing(folio); > - folio_end_writeback(folio); > + if (finished) { > + folio_clear_f2fs_gcing(folio); > + folio_end_writeback(folio); > + } > } > > bio_put(bio); > @@ -2669,7 +2681,7 @@ static void f2fs_ffs_mark_subrange_uptodate(struct folio *folio, size_t offset, > folio_mark_uptodate(folio); > } > > -static void f2fs_ffs_mark_subrange_dirty(struct folio *folio, > +void f2fs_ffs_mark_subrange_dirty(struct folio *folio, > size_t offset, size_t len) > { > struct f2fs_folio_state *ffs; > @@ -2692,6 +2704,86 @@ static void f2fs_ffs_mark_subrange_dirty(struct folio *folio, > spin_unlock_irqrestore(&ffs->state_lock, flags); > } > > +static bool __ffs_clear_subrange_dirty(struct folio *folio, > + struct f2fs_folio_state *ffs, size_t offset, size_t len) > +{ > + unsigned int nr_subpages = folio_nr_pages(folio); > + unsigned int start, end; > + > + start = offset >> PAGE_SHIFT; > + end = (offset + len + PAGE_SIZE - 1) >> PAGE_SHIFT; > + end = min(end, nr_subpages); > + > + bitmap_clear(ffs->state, nr_subpages + start, end - start); > + return find_next_bit(ffs->state, 2 * nr_subpages, nr_subpages) < > + 2 * nr_subpages; > +} > + > +void f2fs_ffs_clear_subrange_dirty(struct folio *folio, size_t offset, size_t len) > +{ > + struct f2fs_folio_state *ffs; > + unsigned long flags; > + > + if (!f2fs_folio_has_ffs(folio)) > + return; > + > + ffs = (struct f2fs_folio_state *)folio->private; > + spin_lock_irqsave(&ffs->state_lock, flags); > + __ffs_clear_subrange_dirty(folio, ffs, offset, len); > + spin_unlock_irqrestore(&ffs->state_lock, flags); > +} > + > +static unsigned int ffs_next_dirty_subpage(struct f2fs_folio_state *ffs, > + const struct folio *folio, unsigned int start, > + unsigned int end) > +{ > + unsigned int nr_subpages = folio_nr_pages(folio); > + > + return find_next_bit(ffs->state, nr_subpages + end + 1, > + nr_subpages + start) - nr_subpages; > +} > + > +static unsigned int ffs_next_clean_subpage(struct f2fs_folio_state *ffs, > + const struct folio *folio, unsigned int start, > + unsigned int end) > +{ > + unsigned int nr_subpages = folio_nr_pages(folio); > + > + return find_next_zero_bit(ffs->state, nr_subpages + end + 1, > + nr_subpages + start) - nr_subpages; > +} > + > +static unsigned int ffs_find_dirty_range(struct folio *folio, > + u64 *range_start, u64 range_end) > +{ > + struct f2fs_folio_state *ffs; > + unsigned int start, end, nr_pages; > + > + if (*range_start >= range_end) > + return 0; > + > + if (!f2fs_folio_has_ffs(folio)) > + return range_end - *range_start; > + > + ffs = (struct f2fs_folio_state *)folio->private; > + start = offset_in_folio(folio, *range_start) >> PAGE_SHIFT; > + end = DIV_ROUND_UP(min_not_zero(offset_in_folio(folio, range_end), > + folio_size(folio)), PAGE_SIZE) - 1; > + > + start = ffs_next_dirty_subpage(ffs, folio, start, end); > + if (start > end) > + return 0; > + > + if (start == end) > + nr_pages = 1; > + else > + nr_pages = ffs_next_clean_subpage(ffs, folio, > + start + 1, end) - start; > + > + *range_start = folio_pos(folio) + ((u64)start << PAGE_SHIFT); > + return (u64)nr_pages << PAGE_SHIFT; > +} > + > static bool find_next_valid_block(const struct folio *folio, > size_t orig_off, size_t *need_off, > size_t len) > @@ -3309,6 +3401,139 @@ int f2fs_do_write_data_page(struct f2fs_io_info *fio) > return err; > } > > +static int f2fs_write_single_data_folio(struct folio *folio, int *submitted, > + struct writeback_control *wbc, > + enum iostat_type io_type, > + u64 start, u64 end) > +{ > + struct inode *inode = folio->mapping->host; > + struct f2fs_sb_info *sbi = F2FS_I_SB(inode); > + bool atomic_commit = f2fs_is_atomic_file(inode) && > + folio_test_f2fs_atomic(folio); > + struct inode *dn_inode = atomic_commit ? > + F2FS_I(inode)->cow_inode : inode; > + u64 pos = folio_pos(folio); > + pgoff_t start_idx = (start - pos) >> PAGE_SHIFT; > + pgoff_t end_idx = (end - 1 - pos) >> PAGE_SHIFT; > + int local_submitted = 0; > + int err = 0; > + > + for (pgoff_t i = start_idx; i <= end_idx; i++) { > + struct dnode_of_data dn; > + struct node_info ni; > + pgoff_t data_idx = folio->index + i; > + bool ipu_force = false; > + struct f2fs_io_info fio = { > + .sbi = sbi, > + .ino = inode->i_ino, > + .type = DATA, > + .op = REQ_OP_WRITE, > + .op_flags = wbc_to_write_flags(wbc), > + .old_blkaddr = NULL_ADDR, > + .folio = folio, > + .folio_offset = i, > + .folio_blkcnt = 1, > + .encrypted_page = NULL, > + .submitted = 0, > + .need_lock = LOCK_DONE, > + .meta_gc = f2fs_meta_inode_gc_required(inode) ? 1 : 0, > + .io_type = io_type, > + .io_wbc = wbc, > + }; > + > + if (f2fs_folio_has_ffs(folio)) { > + struct f2fs_folio_state *ffs = > + (struct f2fs_folio_state *)folio->private; > + > + atomic_inc(&ffs->write_pages_pending); > + } > + > + set_new_dnode(&dn, dn_inode, NULL, NULL, 0); > + > + if (!atomic_commit && need_inplace_update(&fio) && In f2fs_write_single_data_page(), we didn't have !atomic_commit condition in the check? can we drop !atomic_commit check? need_inplace_update() has checked w/ f2fs_used_in_atomic_write(). - need_inplace_update - f2fs_should_update_outplace - f2fs_used_in_atomic_write static inline bool f2fs_used_in_atomic_write(struct inode *inode) { return f2fs_is_atomic_file(inode) || f2fs_is_cow_file(inode); } > + f2fs_lookup_read_extent_cache_block(inode, data_idx, > + &fio.old_blkaddr)) { > + if (!f2fs_is_valid_blkaddr(sbi, fio.old_blkaddr, > + DATA_GENERIC_ENHANCE)) { > + err = -EFSCORRUPTED; > + goto rollback; > + } > + ipu_force = true; > + goto got_it; > + } > + > + err = f2fs_get_dnode_of_data(&dn, data_idx, LOOKUP_NODE); > + if (err) > + goto rollback; > + > + fio.old_blkaddr = dn.data_blkaddr; > + > +got_it: > + if (__is_valid_data_blkaddr(fio.old_blkaddr) && > + !f2fs_is_valid_blkaddr(sbi, fio.old_blkaddr, > + DATA_GENERIC_ENHANCE)) { > + err = -EFSCORRUPTED; > + goto rollback; > + } > + > + if (fio.meta_gc) > + f2fs_wait_on_block_writeback(inode, fio.old_blkaddr); > + > + if (!atomic_commit && (ipu_force || > + (__is_valid_data_blkaddr(fio.old_blkaddr) && > + need_inplace_update(&fio)))) { > + err = f2fs_encrypt_one_page(&fio); > + if (err) > + goto rollback; > + > + f2fs_put_dnode(&dn); > + err = f2fs_inplace_write_data(&fio); > + if (err) { > + if (fscrypt_inode_uses_fs_layer_crypto(inode)) > + fscrypt_finalize_bounce_page( > + &fio.encrypted_page); > + goto rollback_no_dnode; > + } > + > + local_submitted++; > + set_inode_flag(inode, FI_UPDATE_WRITE); trace_f2fs_do_write_data_page(folio, IPU); > + continue; > + } > + > + err = f2fs_get_node_info(sbi, dn.nid, &ni, false); > + if (err) > + goto rollback; > + > + fio.version = ni.version; > + > + err = f2fs_encrypt_one_page(&fio); > + if (err) > + goto rollback; > + > + f2fs_outplace_write_data(&dn, &fio); > + local_submitted++; > + set_inode_flag(inode, FI_APPEND_WRITE); > + trace_f2fs_do_write_data_page(folio, OPU); > + f2fs_put_dnode(&dn); > + continue; > + > +rollback: > + f2fs_put_dnode(&dn); > +rollback_no_dnode: > + if (f2fs_folio_has_ffs(folio)) { > + struct f2fs_folio_state *ffs = > + (struct f2fs_folio_state *)folio->private; > + > + atomic_dec(&ffs->write_pages_pending); > + } > + break; > + } > + > + if (submitted) > + *submitted = local_submitted; > + return err; > +} > + > int f2fs_write_single_data_page(struct folio *folio, int *submitted, > struct bio **bio, > sector_t *last_block, > @@ -3757,6 +3982,170 @@ static int f2fs_write_cache_pages(struct address_space *mapping, > return ret; > } > > +static int f2fs_write_cache_folios(struct address_space *mapping, > + struct writeback_control *wbc, > + enum iostat_type io_type) > +{ > + struct folio *folio = NULL; > + struct inode *inode = mapping->host; > + struct f2fs_sb_info *sbi = F2FS_I_SB(inode); > + struct f2fs_lock_context lc; > + u64 pos = 0; > + u64 end_pos = 0; > + u32 r_len = 0; > + int err = 0; > + int submitted = 0; > + int nwritten = 0; > + bool op_locked = false; > + bool next = false; > + bool retry = false; > + > + if (get_dirty_pages(inode) <= SM_I(sbi)->min_hot_blocks) > + set_inode_flag(inode, FI_HOT_DATA); > + else > + clear_inode_flag(inode, FI_HOT_DATA); > + > + while ((folio = writeback_iter(mapping, wbc, folio, &err))) { > + struct f2fs_folio_state *ffs = NULL; > + u64 isize; > + size_t poff; > + pgoff_t end_index; > + bool verity_in_progress; > + int folio_submitted = 0; > + bool bias_added = false; > + > + submitted = 0; > + next = true; > + retry = false; > + > + if (atomic_read(&sbi->wb_sync_req[DATA]) && > + wbc->sync_mode == WB_SYNC_NONE) { > + folio_redirty_for_writepage(wbc, folio); > + next = false; > + goto retry_out; > + } > +retry: > + pos = folio_pos(folio); > + end_pos = pos + folio_size(folio); > + isize = i_size_read(inode); > + verity_in_progress = f2fs_verity_in_progress(inode); > + poff = 0; > + end_index = 0; > + > + if (retry) { > + if (unlikely(folio->mapping != mapping)) > + goto retry_out; > + > + if (!folio_test_dirty(folio)) > + goto retry_out; > + > + if (folio_test_writeback(folio)) { > + if (wbc->sync_mode == WB_SYNC_NONE) > + goto retry_out; > + f2fs_folio_wait_writeback(folio, DATA, true, true); > + } > + > + if (!folio_clear_dirty_for_io(folio)) > + goto retry_out; > + } > + > + /* To avoid dealing with the complexity for one subrange is in bio > + * while we trylock_op failed before writing another subrange. > + * Try to lock_op before any subrange write for the folio. > + */ > + if (!op_locked) { > + if (!f2fs_trylock_op(sbi, &lc)) { > + folio_redirty_for_writepage(wbc, folio); > + err = 0; > + if (wbc->sync_mode != WB_SYNC_ALL) > + goto retry_out; > + > + retry = true; > + folio_unlock(folio); > + f2fs_io_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT); > + folio_lock(folio); > + goto retry; > + } > + op_locked = true; > + } > + > + if (!verity_in_progress) { > + poff = offset_in_folio(folio, isize); > + end_index = isize >> PAGE_SHIFT; > + > + if (folio->index > end_index || > + (folio->index == end_index && poff == 0)) > + goto out; > + > + if (end_pos > isize) { > + folio_zero_segment(folio, poff, folio_size(folio)); > + end_pos = isize; > + } > + } > + > + folio_start_writeback(folio); > + > + if (folio_test_large(folio)) { > + if (!f2fs_folio_has_ffs(folio)) { Can you explain why there is no ffs for a dirty large folio? Thanks, > + ffs = f2fs_ffs_find_or_alloc(folio); > + f2fs_ffs_mark_subrange_dirty(folio, 0, end_pos - pos); > + } else { > + ffs = (struct f2fs_folio_state *)folio->private; > + } > + if (f2fs_folio_has_ffs(folio) && !bias_added) { > + WARN_ON_ONCE(atomic_read(&ffs->write_pages_pending) != 0); > + atomic_inc(&ffs->write_pages_pending); > + bias_added = true; > + } > + } > + > + while ((r_len = ffs_find_dirty_range(folio, &pos, end_pos))) { > + err = f2fs_write_single_data_folio(folio, &submitted, > + wbc, io_type, pos, pos + r_len); > + folio_submitted += submitted; > + if (err) > + goto out; > + > + nwritten += submitted; > + pos += r_len; > + } > + > + if (!err && folio_submitted && > + f2fs_is_atomic_file(inode) && > + folio_test_f2fs_atomic(folio)) > + folio_clear_f2fs_atomic(folio); > + > +out: > + f2fs_ffs_clear_subrange_dirty(folio, 0, folio_size(folio)); > + inode_dec_dirty_pages(inode); > + > + if (bias_added) { > + if (atomic_dec_and_test(&ffs->write_pages_pending)) > + folio_end_writeback(folio); > + } else if (!folio_submitted && folio_test_writeback(folio)) { > + folio_end_writeback(folio); > + } > + > +retry_out: > + if (folio_test_locked(folio)) > + folio_unlock(folio); > + > + if (op_locked) { > + f2fs_unlock_op(sbi, &lc); > + op_locked = false; > + } > + > + if (err || !next) > + break; > + } > + > + if (nwritten) > + f2fs_submit_merged_write_cond(F2FS_M_SB(mapping), mapping->host, > + NULL, 0, DATA); > + > + return err; > +} > + > static inline bool __should_serialize_io(struct inode *inode, > struct writeback_control *wbc) > { > @@ -3851,7 +4240,10 @@ static int __f2fs_write_data_pages(struct address_space *mapping, > account_writeback(inode, true); > > blk_start_plug(&plug); > - ret = f2fs_write_cache_pages(mapping, wbc, io_type); > + if (mapping_large_folio_support(inode->i_mapping)) > + ret = f2fs_write_cache_folios(mapping, wbc, io_type); > + else > + ret = f2fs_write_cache_pages(mapping, wbc, io_type); > blk_finish_plug(&plug); > > account_writeback(inode, false);