bcachefs: Split up fs-io.[ch]

fs-io.c is too big - time for some reorganization
- fs-dio.c: direct io
- fs-pagecache.c: pagecache data structures (bch_folio), utility code

Signed-off-by: Kent Overstreet <[e-mail]>

fs/bcachefs/Makefile

···
 	fs-common.o		\
 	fs-ioctl.o		\
 	fs-io.o			\
+	fs-io-buffered.o	\
+	fs-io-direct.o		\
+	fs-io-pagecache.o	\
 	fsck.o			\
 	inode.o			\
 	io.o			\

fs/bcachefs/fs-io-buffered.c

···
+// SPDX-License-Identifier: GPL-2.0
+#ifndef NO_BCACHEFS_FS
+
+#include "bcachefs.h"
+#include "alloc_foreground.h"
+#include "bkey_buf.h"
+#include "fs-io.h"
+#include "fs-io-buffered.h"
+#include "fs-io-direct.h"
+#include "fs-io-pagecache.h"
+#include "io.h"
+
+#include <linux/backing-dev.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+
+static inline bool bio_full(struct bio *bio, unsigned len)
+{
+	if (bio->bi_vcnt >= bio->bi_max_vecs)
+		return true;
+	if (bio->bi_iter.bi_size > UINT_MAX - len)
+		return true;
+	return false;
+}
+
+/* readpage(s): */
+
+static void bch2_readpages_end_io(struct bio *bio)
+{
+	struct folio_iter fi;
+
+	bio_for_each_folio_all(fi, bio) {
+		if (!bio->bi_status) {
+			folio_mark_uptodate(fi.folio);
+		} else {
+			folio_clear_uptodate(fi.folio);
+			folio_set_error(fi.folio);
+		}
+		folio_unlock(fi.folio);
+	}
+
+	bio_put(bio);
+}
+
+struct readpages_iter {
+	struct address_space	*mapping;
+	unsigned		idx;
+	folios			folios;
+};
+
+static int readpages_iter_init(struct readpages_iter *iter,
+			       struct readahead_control *ractl)
+{
+	struct folio **fi;
+	int ret;
+
+	memset(iter, 0, sizeof(*iter));
+
+	iter->mapping = ractl->mapping;
+
+	ret = bch2_filemap_get_contig_folios_d(iter->mapping,
+				ractl->_index << PAGE_SHIFT,
+				(ractl->_index + ractl->_nr_pages) << PAGE_SHIFT,
+				0, mapping_gfp_mask(iter->mapping),
+				&iter->folios);
+	if (ret)
+		return ret;
+
+	darray_for_each(iter->folios, fi) {
+		ractl->_nr_pages -= 1U << folio_order(*fi);
+		__bch2_folio_create(*fi, __GFP_NOFAIL|GFP_KERNEL);
+		folio_put(*fi);
+		folio_put(*fi);
+	}
+
+	return 0;
+}
+
+static inline struct folio *readpage_iter_peek(struct readpages_iter *iter)
+{
+	if (iter->idx >= iter->folios.nr)
+		return NULL;
+	return iter->folios.data[iter->idx];
+}
+
+static inline void readpage_iter_advance(struct readpages_iter *iter)
+{
+	iter->idx++;
+}
+
+static bool extent_partial_reads_expensive(struct bkey_s_c k)
+{
+	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+	struct bch_extent_crc_unpacked crc;
+	const union bch_extent_entry *i;
+
+	bkey_for_each_crc(k.k, ptrs, crc, i)
+		if (crc.csum_type || crc.compression_type)
+			return true;
+	return false;
+}
+
+static int readpage_bio_extend(struct btree_trans *trans,
+			       struct readpages_iter *iter,
+			       struct bio *bio,
+			       unsigned sectors_this_extent,
+			       bool get_more)
+{
+	/* Don't hold btree locks while allocating memory: */
+	bch2_trans_unlock(trans);
+
+	while (bio_sectors(bio) < sectors_this_extent &&
+	       bio->bi_vcnt < bio->bi_max_vecs) {
+		struct folio *folio = readpage_iter_peek(iter);
+		int ret;
+
+		if (folio) {
+			readpage_iter_advance(iter);
+		} else {
+			pgoff_t folio_offset = bio_end_sector(bio) >> PAGE_SECTORS_SHIFT;
+
+			if (!get_more)
+				break;
+
+			folio = xa_load(&iter->mapping->i_pages, folio_offset);
+			if (folio && !xa_is_value(folio))
+				break;
+
+			folio = filemap_alloc_folio(readahead_gfp_mask(iter->mapping), 0);
+			if (!folio)
+				break;
+
+			if (!__bch2_folio_create(folio, GFP_KERNEL)) {
+				folio_put(folio);
+				break;
+			}
+
+			ret = filemap_add_folio(iter->mapping, folio, folio_offset, GFP_KERNEL);
+			if (ret) {
+				__bch2_folio_release(folio);
+				folio_put(folio);
+				break;
+			}
+
+			folio_put(folio);
+		}
+
+		BUG_ON(folio_sector(folio) != bio_end_sector(bio));
+
+		BUG_ON(!bio_add_folio(bio, folio, folio_size(folio), 0));
+	}
+
+	return bch2_trans_relock(trans);
+}
+
+static void bchfs_read(struct btree_trans *trans,
+		       struct bch_read_bio *rbio,
+		       subvol_inum inum,
+		       struct readpages_iter *readpages_iter)
+{
+	struct bch_fs *c = trans->c;
+	struct btree_iter iter;
+	struct bkey_buf sk;
+	int flags = BCH_READ_RETRY_IF_STALE|
+		BCH_READ_MAY_PROMOTE;
+	u32 snapshot;
+	int ret = 0;
+
+	rbio->c = c;
+	rbio->start_time = local_clock();
+	rbio->subvol = inum.subvol;
+
+	bch2_bkey_buf_init(&sk);
+retry:
+	bch2_trans_begin(trans);
+	iter = (struct btree_iter) { NULL };
+
+	ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
+	if (ret)
+		goto err;
+
+	bch2_trans_iter_init(trans, &iter, BTREE_ID_extents,
+			     SPOS(inum.inum, rbio->bio.bi_iter.bi_sector, snapshot),
+			     BTREE_ITER_SLOTS);
+	while (1) {
+		struct bkey_s_c k;
+		unsigned bytes, sectors, offset_into_extent;
+		enum btree_id data_btree = BTREE_ID_extents;
+
+		/*
+		 * read_extent -> io_time_reset may cause a transaction restart
+		 * without returning an error, we need to check for that here:
+		 */
+		ret = bch2_trans_relock(trans);
+		if (ret)
+			break;
+
+		bch2_btree_iter_set_pos(&iter,
+				POS(inum.inum, rbio->bio.bi_iter.bi_sector));
+
+		k = bch2_btree_iter_peek_slot(&iter);
+		ret = bkey_err(k);
+		if (ret)
+			break;
+
+		offset_into_extent = iter.pos.offset -
+			bkey_start_offset(k.k);
+		sectors = k.k->size - offset_into_extent;
+
+		bch2_bkey_buf_reassemble(&sk, c, k);
+
+		ret = bch2_read_indirect_extent(trans, &data_btree,
+					&offset_into_extent, &sk);
+		if (ret)
+			break;
+
+		k = bkey_i_to_s_c(sk.k);
+
+		sectors = min(sectors, k.k->size - offset_into_extent);
+
+		if (readpages_iter) {
+			ret = readpage_bio_extend(trans, readpages_iter, &rbio->bio, sectors,
+						  extent_partial_reads_expensive(k));
+			if (ret)
+				break;
+		}
+
+		bytes = min(sectors, bio_sectors(&rbio->bio)) << 9;
+		swap(rbio->bio.bi_iter.bi_size, bytes);
+
+		if (rbio->bio.bi_iter.bi_size == bytes)
+			flags |= BCH_READ_LAST_FRAGMENT;
+
+		bch2_bio_page_state_set(&rbio->bio, k);
+
+		bch2_read_extent(trans, rbio, iter.pos,
+				 data_btree, k, offset_into_extent, flags);
+
+		if (flags & BCH_READ_LAST_FRAGMENT)
+			break;
+
+		swap(rbio->bio.bi_iter.bi_size, bytes);
+		bio_advance(&rbio->bio, bytes);
+
+		ret = btree_trans_too_many_iters(trans);
+		if (ret)
+			break;
+	}
+err:
+	bch2_trans_iter_exit(trans, &iter);
+
+	if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+		goto retry;
+
+	if (ret) {
+		bch_err_inum_offset_ratelimited(c,
+				iter.pos.inode,
+				iter.pos.offset << 9,
+				"read error %i from btree lookup", ret);
+		rbio->bio.bi_status = BLK_STS_IOERR;
+		bio_endio(&rbio->bio);
+	}
+
+	bch2_bkey_buf_exit(&sk, c);
+}
+
+void bch2_readahead(struct readahead_control *ractl)
+{
+	struct bch_inode_info *inode = to_bch_ei(ractl->mapping->host);
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct bch_io_opts opts;
+	struct btree_trans trans;
+	struct folio *folio;
+	struct readpages_iter readpages_iter;
+	int ret;
+
+	bch2_inode_opts_get(&opts, c, &inode->ei_inode);
+
+	ret = readpages_iter_init(&readpages_iter, ractl);
+	BUG_ON(ret);
+
+	bch2_trans_init(&trans, c, 0, 0);
+
+	bch2_pagecache_add_get(inode);
+
+	while ((folio = readpage_iter_peek(&readpages_iter))) {
+		unsigned n = min_t(unsigned,
+				   readpages_iter.folios.nr -
+				   readpages_iter.idx,
+				   BIO_MAX_VECS);
+		struct bch_read_bio *rbio =
+			rbio_init(bio_alloc_bioset(NULL, n, REQ_OP_READ,
+						   GFP_KERNEL, &c->bio_read),
+				  opts);
+
+		readpage_iter_advance(&readpages_iter);
+
+		rbio->bio.bi_iter.bi_sector = folio_sector(folio);
+		rbio->bio.bi_end_io = bch2_readpages_end_io;
+		BUG_ON(!bio_add_folio(&rbio->bio, folio, folio_size(folio), 0));
+
+		bchfs_read(&trans, rbio, inode_inum(inode),
+			   &readpages_iter);
+		bch2_trans_unlock(&trans);
+	}
+
+	bch2_pagecache_add_put(inode);
+
+	bch2_trans_exit(&trans);
+	darray_exit(&readpages_iter.folios);
+}
+
+static void __bchfs_readfolio(struct bch_fs *c, struct bch_read_bio *rbio,
+			     subvol_inum inum, struct folio *folio)
+{
+	struct btree_trans trans;
+
+	bch2_folio_create(folio, __GFP_NOFAIL);
+
+	rbio->bio.bi_opf = REQ_OP_READ|REQ_SYNC;
+	rbio->bio.bi_iter.bi_sector = folio_sector(folio);
+	BUG_ON(!bio_add_folio(&rbio->bio, folio, folio_size(folio), 0));
+
+	bch2_trans_init(&trans, c, 0, 0);
+	bchfs_read(&trans, rbio, inum, NULL);
+	bch2_trans_exit(&trans);
+}
+
+static void bch2_read_single_folio_end_io(struct bio *bio)
+{
+	complete(bio->bi_private);
+}
+
+int bch2_read_single_folio(struct folio *folio, struct address_space *mapping)
+{
+	struct bch_inode_info *inode = to_bch_ei(mapping->host);
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct bch_read_bio *rbio;
+	struct bch_io_opts opts;
+	int ret;
+	DECLARE_COMPLETION_ONSTACK(done);
+
+	bch2_inode_opts_get(&opts, c, &inode->ei_inode);
+
+	rbio = rbio_init(bio_alloc_bioset(NULL, 1, REQ_OP_READ, GFP_KERNEL, &c->bio_read),
+			 opts);
+	rbio->bio.bi_private = &done;
+	rbio->bio.bi_end_io = bch2_read_single_folio_end_io;
+
+	__bchfs_readfolio(c, rbio, inode_inum(inode), folio);
+	wait_for_completion(&done);
+
+	ret = blk_status_to_errno(rbio->bio.bi_status);
+	bio_put(&rbio->bio);
+
+	if (ret < 0)
+		return ret;
+
+	folio_mark_uptodate(folio);
+	return 0;
+}
+
+int bch2_read_folio(struct file *file, struct folio *folio)
+{
+	int ret;
+
+	ret = bch2_read_single_folio(folio, folio->mapping);
+	folio_unlock(folio);
+	return bch2_err_class(ret);
+}
+
+/* writepages: */
+
+struct bch_writepage_io {
+	struct bch_inode_info		*inode;
+
+	/* must be last: */
+	struct bch_write_op		op;
+};
+
+struct bch_writepage_state {
+	struct bch_writepage_io	*io;
+	struct bch_io_opts	opts;
+	struct bch_folio_sector	*tmp;
+	unsigned		tmp_sectors;
+};
+
+static inline struct bch_writepage_state bch_writepage_state_init(struct bch_fs *c,
+								  struct bch_inode_info *inode)
+{
+	struct bch_writepage_state ret = { 0 };
+
+	bch2_inode_opts_get(&ret.opts, c, &inode->ei_inode);
+	return ret;
+}
+
+static void bch2_writepage_io_done(struct bch_write_op *op)
+{
+	struct bch_writepage_io *io =
+		container_of(op, struct bch_writepage_io, op);
+	struct bch_fs *c = io->op.c;
+	struct bio *bio = &io->op.wbio.bio;
+	struct folio_iter fi;
+	unsigned i;
+
+	if (io->op.error) {
+		set_bit(EI_INODE_ERROR, &io->inode->ei_flags);
+
+		bio_for_each_folio_all(fi, bio) {
+			struct bch_folio *s;
+
+			folio_set_error(fi.folio);
+			mapping_set_error(fi.folio->mapping, -EIO);
+
+			s = __bch2_folio(fi.folio);
+			spin_lock(&s->lock);
+			for (i = 0; i < folio_sectors(fi.folio); i++)
+				s->s[i].nr_replicas = 0;
+			spin_unlock(&s->lock);
+		}
+	}
+
+	if (io->op.flags & BCH_WRITE_WROTE_DATA_INLINE) {
+		bio_for_each_folio_all(fi, bio) {
+			struct bch_folio *s;
+
+			s = __bch2_folio(fi.folio);
+			spin_lock(&s->lock);
+			for (i = 0; i < folio_sectors(fi.folio); i++)
+				s->s[i].nr_replicas = 0;
+			spin_unlock(&s->lock);
+		}
+	}
+
+	/*
+	 * racing with fallocate can cause us to add fewer sectors than
+	 * expected - but we shouldn't add more sectors than expected:
+	 */
+	WARN_ON_ONCE(io->op.i_sectors_delta > 0);
+
+	/*
+	 * (error (due to going RO) halfway through a page can screw that up
+	 * slightly)
+	 * XXX wtf?
+	   BUG_ON(io->op.op.i_sectors_delta >= PAGE_SECTORS);
+	 */
+
+	/*
+	 * PageWriteback is effectively our ref on the inode - fixup i_blocks
+	 * before calling end_page_writeback:
+	 */
+	bch2_i_sectors_acct(c, io->inode, NULL, io->op.i_sectors_delta);
+
+	bio_for_each_folio_all(fi, bio) {
+		struct bch_folio *s = __bch2_folio(fi.folio);
+
+		if (atomic_dec_and_test(&s->write_count))
+			folio_end_writeback(fi.folio);
+	}
+
+	bio_put(&io->op.wbio.bio);
+}
+
+static void bch2_writepage_do_io(struct bch_writepage_state *w)
+{
+	struct bch_writepage_io *io = w->io;
+
+	w->io = NULL;
+	closure_call(&io->op.cl, bch2_write, NULL, NULL);
+}
+
+/*
+ * Get a bch_writepage_io and add @page to it - appending to an existing one if
+ * possible, else allocating a new one:
+ */
+static void bch2_writepage_io_alloc(struct bch_fs *c,
+				    struct writeback_control *wbc,
+				    struct bch_writepage_state *w,
+				    struct bch_inode_info *inode,
+				    u64 sector,
+				    unsigned nr_replicas)
+{
+	struct bch_write_op *op;
+
+	w->io = container_of(bio_alloc_bioset(NULL, BIO_MAX_VECS,
+					      REQ_OP_WRITE,
+					      GFP_KERNEL,
+					      &c->writepage_bioset),
+			     struct bch_writepage_io, op.wbio.bio);
+
+	w->io->inode		= inode;
+	op			= &w->io->op;
+	bch2_write_op_init(op, c, w->opts);
+	op->target		= w->opts.foreground_target;
+	op->nr_replicas		= nr_replicas;
+	op->res.nr_replicas	= nr_replicas;
+	op->write_point		= writepoint_hashed(inode->ei_last_dirtied);
+	op->subvol		= inode->ei_subvol;
+	op->pos			= POS(inode->v.i_ino, sector);
+	op->end_io		= bch2_writepage_io_done;
+	op->devs_need_flush	= &inode->ei_devs_need_flush;
+	op->wbio.bio.bi_iter.bi_sector = sector;
+	op->wbio.bio.bi_opf	= wbc_to_write_flags(wbc);
+}
+
+static int __bch2_writepage(struct folio *folio,
+			    struct writeback_control *wbc,
+			    void *data)
+{
+	struct bch_inode_info *inode = to_bch_ei(folio->mapping->host);
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct bch_writepage_state *w = data;
+	struct bch_folio *s;
+	unsigned i, offset, f_sectors, nr_replicas_this_write = U32_MAX;
+	loff_t i_size = i_size_read(&inode->v);
+	int ret;
+
+	EBUG_ON(!folio_test_uptodate(folio));
+
+	/* Is the folio fully inside i_size? */
+	if (folio_end_pos(folio) <= i_size)
+		goto do_io;
+
+	/* Is the folio fully outside i_size? (truncate in progress) */
+	if (folio_pos(folio) >= i_size) {
+		folio_unlock(folio);
+		return 0;
+	}
+
+	/*
+	 * The folio straddles i_size.  It must be zeroed out on each and every
+	 * writepage invocation because it may be mmapped.  "A file is mapped
+	 * in multiples of the folio size.  For a file that is not a multiple of
+	 * the  folio size, the remaining memory is zeroed when mapped, and
+	 * writes to that region are not written out to the file."
+	 */
+	folio_zero_segment(folio,
+			   i_size - folio_pos(folio),
+			   folio_size(folio));
+do_io:
+	f_sectors = folio_sectors(folio);
+	s = bch2_folio(folio);
+
+	if (f_sectors > w->tmp_sectors) {
+		kfree(w->tmp);
+		w->tmp = kcalloc(f_sectors, sizeof(struct bch_folio_sector), __GFP_NOFAIL);
+		w->tmp_sectors = f_sectors;
+	}
+
+	/*
+	 * Things get really hairy with errors during writeback:
+	 */
+	ret = bch2_get_folio_disk_reservation(c, inode, folio, false);
+	BUG_ON(ret);
+
+	/* Before unlocking the page, get copy of reservations: */
+	spin_lock(&s->lock);
+	memcpy(w->tmp, s->s, sizeof(struct bch_folio_sector) * f_sectors);
+
+	for (i = 0; i < f_sectors; i++) {
+		if (s->s[i].state < SECTOR_dirty)
+			continue;
+
+		nr_replicas_this_write =
+			min_t(unsigned, nr_replicas_this_write,
+			      s->s[i].nr_replicas +
+			      s->s[i].replicas_reserved);
+	}
+
+	for (i = 0; i < f_sectors; i++) {
+		if (s->s[i].state < SECTOR_dirty)
+			continue;
+
+		s->s[i].nr_replicas = w->opts.compression
+			? 0 : nr_replicas_this_write;
+
+		s->s[i].replicas_reserved = 0;
+		bch2_folio_sector_set(folio, s, i, SECTOR_allocated);
+	}
+	spin_unlock(&s->lock);
+
+	BUG_ON(atomic_read(&s->write_count));
+	atomic_set(&s->write_count, 1);
+
+	BUG_ON(folio_test_writeback(folio));
+	folio_start_writeback(folio);
+
+	folio_unlock(folio);
+
+	offset = 0;
+	while (1) {
+		unsigned sectors = 0, dirty_sectors = 0, reserved_sectors = 0;
+		u64 sector;
+
+		while (offset < f_sectors &&
+		       w->tmp[offset].state < SECTOR_dirty)
+			offset++;
+
+		if (offset == f_sectors)
+			break;
+
+		while (offset + sectors < f_sectors &&
+		       w->tmp[offset + sectors].state >= SECTOR_dirty) {
+			reserved_sectors += w->tmp[offset + sectors].replicas_reserved;
+			dirty_sectors += w->tmp[offset + sectors].state == SECTOR_dirty;
+			sectors++;
+		}
+		BUG_ON(!sectors);
+
+		sector = folio_sector(folio) + offset;
+
+		if (w->io &&
+		    (w->io->op.res.nr_replicas != nr_replicas_this_write ||
+		     bio_full(&w->io->op.wbio.bio, sectors << 9) ||
+		     w->io->op.wbio.bio.bi_iter.bi_size + (sectors << 9) >=
+		     (BIO_MAX_VECS * PAGE_SIZE) ||
+		     bio_end_sector(&w->io->op.wbio.bio) != sector))
+			bch2_writepage_do_io(w);
+
+		if (!w->io)
+			bch2_writepage_io_alloc(c, wbc, w, inode, sector,
+						nr_replicas_this_write);
+
+		atomic_inc(&s->write_count);
+
+		BUG_ON(inode != w->io->inode);
+		BUG_ON(!bio_add_folio(&w->io->op.wbio.bio, folio,
+				     sectors << 9, offset << 9));
+
+		/* Check for writing past i_size: */
+		WARN_ONCE((bio_end_sector(&w->io->op.wbio.bio) << 9) >
+			  round_up(i_size, block_bytes(c)) &&
+			  !test_bit(BCH_FS_EMERGENCY_RO, &c->flags),
+			  "writing past i_size: %llu > %llu (unrounded %llu)\n",
+			  bio_end_sector(&w->io->op.wbio.bio) << 9,
+			  round_up(i_size, block_bytes(c)),
+			  i_size);
+
+		w->io->op.res.sectors += reserved_sectors;
+		w->io->op.i_sectors_delta -= dirty_sectors;
+		w->io->op.new_i_size = i_size;
+
+		offset += sectors;
+	}
+
+	if (atomic_dec_and_test(&s->write_count))
+		folio_end_writeback(folio);
+
+	return 0;
+}
+
+int bch2_writepages(struct address_space *mapping, struct writeback_control *wbc)
+{
+	struct bch_fs *c = mapping->host->i_sb->s_fs_info;
+	struct bch_writepage_state w =
+		bch_writepage_state_init(c, to_bch_ei(mapping->host));
+	struct blk_plug plug;
+	int ret;
+
+	blk_start_plug(&plug);
+	ret = write_cache_pages(mapping, wbc, __bch2_writepage, &w);
+	if (w.io)
+		bch2_writepage_do_io(&w);
+	blk_finish_plug(&plug);
+	kfree(w.tmp);
+	return bch2_err_class(ret);
+}
+
+/* buffered writes: */
+
+int bch2_write_begin(struct file *file, struct address_space *mapping,
+		     loff_t pos, unsigned len,
+		     struct page **pagep, void **fsdata)
+{
+	struct bch_inode_info *inode = to_bch_ei(mapping->host);
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct bch2_folio_reservation *res;
+	struct folio *folio;
+	unsigned offset;
+	int ret = -ENOMEM;
+
+	res = kmalloc(sizeof(*res), GFP_KERNEL);
+	if (!res)
+		return -ENOMEM;
+
+	bch2_folio_reservation_init(c, inode, res);
+	*fsdata = res;
+
+	bch2_pagecache_add_get(inode);
+
+	folio = __filemap_get_folio(mapping, pos >> PAGE_SHIFT,
+				FGP_LOCK|FGP_WRITE|FGP_CREAT|FGP_STABLE,
+				mapping_gfp_mask(mapping));
+	if (IS_ERR_OR_NULL(folio))
+		goto err_unlock;
+
+	if (folio_test_uptodate(folio))
+		goto out;
+
+	offset = pos - folio_pos(folio);
+	len = min_t(size_t, len, folio_end_pos(folio) - pos);
+
+	/* If we're writing entire folio, don't need to read it in first: */
+	if (!offset && len == folio_size(folio))
+		goto out;
+
+	if (!offset && pos + len >= inode->v.i_size) {
+		folio_zero_segment(folio, len, folio_size(folio));
+		flush_dcache_folio(folio);
+		goto out;
+	}
+
+	if (folio_pos(folio) >= inode->v.i_size) {
+		folio_zero_segments(folio, 0, offset, offset + len, folio_size(folio));
+		flush_dcache_folio(folio);
+		goto out;
+	}
+readpage:
+	ret = bch2_read_single_folio(folio, mapping);
+	if (ret)
+		goto err;
+out:
+	ret = bch2_folio_set(c, inode_inum(inode), &folio, 1);
+	if (ret)
+		goto err;
+
+	ret = bch2_folio_reservation_get(c, inode, folio, res, offset, len);
+	if (ret) {
+		if (!folio_test_uptodate(folio)) {
+			/*
+			 * If the folio hasn't been read in, we won't know if we
+			 * actually need a reservation - we don't actually need
+			 * to read here, we just need to check if the folio is
+			 * fully backed by uncompressed data:
+			 */
+			goto readpage;
+		}
+
+		goto err;
+	}
+
+	*pagep = &folio->page;
+	return 0;
+err:
+	folio_unlock(folio);
+	folio_put(folio);
+	*pagep = NULL;
+err_unlock:
+	bch2_pagecache_add_put(inode);
+	kfree(res);
+	*fsdata = NULL;
+	return bch2_err_class(ret);
+}
+
+int bch2_write_end(struct file *file, struct address_space *mapping,
+		   loff_t pos, unsigned len, unsigned copied,
+		   struct page *page, void *fsdata)
+{
+	struct bch_inode_info *inode = to_bch_ei(mapping->host);
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct bch2_folio_reservation *res = fsdata;
+	struct folio *folio = page_folio(page);
+	unsigned offset = pos - folio_pos(folio);
+
+	lockdep_assert_held(&inode->v.i_rwsem);
+	BUG_ON(offset + copied > folio_size(folio));
+
+	if (unlikely(copied < len && !folio_test_uptodate(folio))) {
+		/*
+		 * The folio needs to be read in, but that would destroy
+		 * our partial write - simplest thing is to just force
+		 * userspace to redo the write:
+		 */
+		folio_zero_range(folio, 0, folio_size(folio));
+		flush_dcache_folio(folio);
+		copied = 0;
+	}
+
+	spin_lock(&inode->v.i_lock);
+	if (pos + copied > inode->v.i_size)
+		i_size_write(&inode->v, pos + copied);
+	spin_unlock(&inode->v.i_lock);
+
+	if (copied) {
+		if (!folio_test_uptodate(folio))
+			folio_mark_uptodate(folio);
+
+		bch2_set_folio_dirty(c, inode, folio, res, offset, copied);
+
+		inode->ei_last_dirtied = (unsigned long) current;
+	}
+
+	folio_unlock(folio);
+	folio_put(folio);
+	bch2_pagecache_add_put(inode);
+
+	bch2_folio_reservation_put(c, inode, res);
+	kfree(res);
+
+	return copied;
+}
+
+static noinline void folios_trunc(folios *folios, struct folio **fi)
+{
+	while (folios->data + folios->nr > fi) {
+		struct folio *f = darray_pop(folios);
+
+		folio_unlock(f);
+		folio_put(f);
+	}
+}
+
+static int __bch2_buffered_write(struct bch_inode_info *inode,
+				 struct address_space *mapping,
+				 struct iov_iter *iter,
+				 loff_t pos, unsigned len)
+{
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct bch2_folio_reservation res;
+	folios folios;
+	struct folio **fi, *f;
+	unsigned copied = 0, f_offset;
+	u64 end = pos + len, f_pos;
+	loff_t last_folio_pos = inode->v.i_size;
+	int ret = 0;
+
+	BUG_ON(!len);
+
+	bch2_folio_reservation_init(c, inode, &res);
+	darray_init(&folios);
+
+	ret = bch2_filemap_get_contig_folios_d(mapping, pos, end,
+				   FGP_LOCK|FGP_WRITE|FGP_STABLE|FGP_CREAT,
+				   mapping_gfp_mask(mapping),
+				   &folios);
+	if (ret)
+		goto out;
+
+	BUG_ON(!folios.nr);
+
+	f = darray_first(folios);
+	if (pos != folio_pos(f) && !folio_test_uptodate(f)) {
+		ret = bch2_read_single_folio(f, mapping);
+		if (ret)
+			goto out;
+	}
+
+	f = darray_last(folios);
+	end = min(end, folio_end_pos(f));
+	last_folio_pos = folio_pos(f);
+	if (end != folio_end_pos(f) && !folio_test_uptodate(f)) {
+		if (end >= inode->v.i_size) {
+			folio_zero_range(f, 0, folio_size(f));
+		} else {
+			ret = bch2_read_single_folio(f, mapping);
+			if (ret)
+				goto out;
+		}
+	}
+
+	ret = bch2_folio_set(c, inode_inum(inode), folios.data, folios.nr);
+	if (ret)
+		goto out;
+
+	f_pos = pos;
+	f_offset = pos - folio_pos(darray_first(folios));
+	darray_for_each(folios, fi) {
+		struct folio *f = *fi;
+		u64 f_len = min(end, folio_end_pos(f)) - f_pos;
+
+		/*
+		 * XXX: per POSIX and fstests generic/275, on -ENOSPC we're
+		 * supposed to write as much as we have disk space for.
+		 *
+		 * On failure here we should still write out a partial page if
+		 * we aren't completely out of disk space - we don't do that
+		 * yet:
+		 */
+		ret = bch2_folio_reservation_get(c, inode, f, &res, f_offset, f_len);
+		if (unlikely(ret)) {
+			folios_trunc(&folios, fi);
+			if (!folios.nr)
+				goto out;
+
+			end = min(end, folio_end_pos(darray_last(folios)));
+			break;
+		}
+
+		f_pos = folio_end_pos(f);
+		f_offset = 0;
+	}
+
+	if (mapping_writably_mapped(mapping))
+		darray_for_each(folios, fi)
+			flush_dcache_folio(*fi);
+
+	f_pos = pos;
+	f_offset = pos - folio_pos(darray_first(folios));
+	darray_for_each(folios, fi) {
+		struct folio *f = *fi;
+		u64 f_len = min(end, folio_end_pos(f)) - f_pos;
+		unsigned f_copied = copy_page_from_iter_atomic(&f->page, f_offset, f_len, iter);
+
+		if (!f_copied) {
+			folios_trunc(&folios, fi);
+			break;
+		}
+
+		if (!folio_test_uptodate(f) &&
+		    f_copied != folio_size(f) &&
+		    pos + copied + f_copied < inode->v.i_size) {
+			folio_zero_range(f, 0, folio_size(f));
+			folios_trunc(&folios, fi);
+			break;
+		}
+
+		flush_dcache_folio(f);
+		copied += f_copied;
+
+		if (f_copied != f_len) {
+			folios_trunc(&folios, fi + 1);
+			break;
+		}
+
+		f_pos = folio_end_pos(f);
+		f_offset = 0;
+	}
+
+	if (!copied)
+		goto out;
+
+	end = pos + copied;
+
+	spin_lock(&inode->v.i_lock);
+	if (end > inode->v.i_size)
+		i_size_write(&inode->v, end);
+	spin_unlock(&inode->v.i_lock);
+
+	f_pos = pos;
+	f_offset = pos - folio_pos(darray_first(folios));
+	darray_for_each(folios, fi) {
+		struct folio *f = *fi;
+		u64 f_len = min(end, folio_end_pos(f)) - f_pos;
+
+		if (!folio_test_uptodate(f))
+			folio_mark_uptodate(f);
+
+		bch2_set_folio_dirty(c, inode, f, &res, f_offset, f_len);
+
+		f_pos = folio_end_pos(f);
+		f_offset = 0;
+	}
+
+	inode->ei_last_dirtied = (unsigned long) current;
+out:
+	darray_for_each(folios, fi) {
+		folio_unlock(*fi);
+		folio_put(*fi);
+	}
+
+	/*
+	 * If the last folio added to the mapping starts beyond current EOF, we
+	 * performed a short write but left around at least one post-EOF folio.
+	 * Clean up the mapping before we return.
+	 */
+	if (last_folio_pos >= inode->v.i_size)
+		truncate_pagecache(&inode->v, inode->v.i_size);
+
+	darray_exit(&folios);
+	bch2_folio_reservation_put(c, inode, &res);
+
+	return copied ?: ret;
+}
+
+static ssize_t bch2_buffered_write(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct file *file = iocb->ki_filp;
+	struct address_space *mapping = file->f_mapping;
+	struct bch_inode_info *inode = file_bch_inode(file);
+	loff_t pos = iocb->ki_pos;
+	ssize_t written = 0;
+	int ret = 0;
+
+	bch2_pagecache_add_get(inode);
+
+	do {
+		unsigned offset = pos & (PAGE_SIZE - 1);
+		unsigned bytes = iov_iter_count(iter);
+again:
+		/*
+		 * Bring in the user page that we will copy from _first_.
+		 * Otherwise there's a nasty deadlock on copying from the
+		 * same page as we're writing to, without it being marked
+		 * up-to-date.
+		 *
+		 * 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.
+		 */
+		if (unlikely(fault_in_iov_iter_readable(iter, bytes))) {
+			bytes = min_t(unsigned long, iov_iter_count(iter),
+				      PAGE_SIZE - offset);
+
+			if (unlikely(fault_in_iov_iter_readable(iter, bytes))) {
+				ret = -EFAULT;
+				break;
+			}
+		}
+
+		if (unlikely(fatal_signal_pending(current))) {
+			ret = -EINTR;
+			break;
+		}
+
+		ret = __bch2_buffered_write(inode, mapping, iter, pos, bytes);
+		if (unlikely(ret < 0))
+			break;
+
+		cond_resched();
+
+		if (unlikely(ret == 0)) {
+			/*
+			 * If we were unable to copy any data at all, we must
+			 * fall back to a single segment length write.
+			 *
+			 * If we didn't fallback here, we could livelock
+			 * because not all segments in the iov can be copied at
+			 * once without a pagefault.
+			 */
+			bytes = min_t(unsigned long, PAGE_SIZE - offset,
+				      iov_iter_single_seg_count(iter));
+			goto again;
+		}
+		pos += ret;
+		written += ret;
+		ret = 0;
+
+		balance_dirty_pages_ratelimited(mapping);
+	} while (iov_iter_count(iter));
+
+	bch2_pagecache_add_put(inode);
+
+	return written ? written : ret;
+}
+
+ssize_t bch2_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct bch_inode_info *inode = file_bch_inode(file);
+	ssize_t ret;
+
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		ret = bch2_direct_write(iocb, from);
+		goto out;
+	}
+
+	inode_lock(&inode->v);
+
+	ret = generic_write_checks(iocb, from);
+	if (ret <= 0)
+		goto unlock;
+
+	ret = file_remove_privs(file);
+	if (ret)
+		goto unlock;
+
+	ret = file_update_time(file);
+	if (ret)
+		goto unlock;
+
+	ret = bch2_buffered_write(iocb, from);
+	if (likely(ret > 0))
+		iocb->ki_pos += ret;
+unlock:
+	inode_unlock(&inode->v);
+
+	if (ret > 0)
+		ret = generic_write_sync(iocb, ret);
+out:
+	return bch2_err_class(ret);
+}
+
+void bch2_fs_fs_io_buffered_exit(struct bch_fs *c)
+{
+	bioset_exit(&c->writepage_bioset);
+}
+
+int bch2_fs_fs_io_buffered_init(struct bch_fs *c)
+{
+	if (bioset_init(&c->writepage_bioset,
+			4, offsetof(struct bch_writepage_io, op.wbio.bio),
+			BIOSET_NEED_BVECS))
+		return -BCH_ERR_ENOMEM_writepage_bioset_init;
+
+	return 0;
+}
+
+#endif /* NO_BCACHEFS_FS */

fs/bcachefs/fs-io-buffered.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_FS_IO_BUFFERED_H
+#define _BCACHEFS_FS_IO_BUFFERED_H
+
+#ifndef NO_BCACHEFS_FS
+
+int bch2_read_single_folio(struct folio *, struct address_space *);
+int bch2_read_folio(struct file *, struct folio *);
+
+int bch2_writepages(struct address_space *, struct writeback_control *);
+void bch2_readahead(struct readahead_control *);
+
+int bch2_write_begin(struct file *, struct address_space *, loff_t,
+		     unsigned, struct page **, void **);
+int bch2_write_end(struct file *, struct address_space *, loff_t,
+		   unsigned, unsigned, struct page *, void *);
+
+ssize_t bch2_write_iter(struct kiocb *, struct iov_iter *);
+
+void bch2_fs_fs_io_buffered_exit(struct bch_fs *);
+int bch2_fs_fs_io_buffered_init(struct bch_fs *);
+#else
+static inline void bch2_fs_fs_io_buffered_exit(struct bch_fs *c) {}
+static inline int bch2_fs_fs_io_buffered_init(struct bch_fs *c) { return 0; }
+#endif
+
+#endif /* _BCACHEFS_FS_IO_BUFFERED_H */

fs/bcachefs/fs-io-direct.c

···
+// SPDX-License-Identifier: GPL-2.0
+#ifndef NO_BCACHEFS_FS
+
+#include "bcachefs.h"
+#include "alloc_foreground.h"
+#include "fs.h"
+#include "fs-io.h"
+#include "fs-io-direct.h"
+#include "fs-io-pagecache.h"
+#include "io.h"
+
+#include <linux/kthread.h>
+#include <linux/pagemap.h>
+#include <linux/task_io_accounting_ops.h>
+
+/* O_DIRECT reads */
+
+struct dio_read {
+	struct closure			cl;
+	struct kiocb			*req;
+	long				ret;
+	bool				should_dirty;
+	struct bch_read_bio		rbio;
+};
+
+static void bio_check_or_release(struct bio *bio, bool check_dirty)
+{
+	if (check_dirty) {
+		bio_check_pages_dirty(bio);
+	} else {
+		bio_release_pages(bio, false);
+		bio_put(bio);
+	}
+}
+
+static void bch2_dio_read_complete(struct closure *cl)
+{
+	struct dio_read *dio = container_of(cl, struct dio_read, cl);
+
+	dio->req->ki_complete(dio->req, dio->ret);
+	bio_check_or_release(&dio->rbio.bio, dio->should_dirty);
+}
+
+static void bch2_direct_IO_read_endio(struct bio *bio)
+{
+	struct dio_read *dio = bio->bi_private;
+
+	if (bio->bi_status)
+		dio->ret = blk_status_to_errno(bio->bi_status);
+
+	closure_put(&dio->cl);
+}
+
+static void bch2_direct_IO_read_split_endio(struct bio *bio)
+{
+	struct dio_read *dio = bio->bi_private;
+	bool should_dirty = dio->should_dirty;
+
+	bch2_direct_IO_read_endio(bio);
+	bio_check_or_release(bio, should_dirty);
+}
+
+static int bch2_direct_IO_read(struct kiocb *req, struct iov_iter *iter)
+{
+	struct file *file = req->ki_filp;
+	struct bch_inode_info *inode = file_bch_inode(file);
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct bch_io_opts opts;
+	struct dio_read *dio;
+	struct bio *bio;
+	loff_t offset = req->ki_pos;
+	bool sync = is_sync_kiocb(req);
+	size_t shorten;
+	ssize_t ret;
+
+	bch2_inode_opts_get(&opts, c, &inode->ei_inode);
+
+	if ((offset|iter->count) & (block_bytes(c) - 1))
+		return -EINVAL;
+
+	ret = min_t(loff_t, iter->count,
+		    max_t(loff_t, 0, i_size_read(&inode->v) - offset));
+
+	if (!ret)
+		return ret;
+
+	shorten = iov_iter_count(iter) - round_up(ret, block_bytes(c));
+	iter->count -= shorten;
+
+	bio = bio_alloc_bioset(NULL,
+			       bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
+			       REQ_OP_READ,
+			       GFP_KERNEL,
+			       &c->dio_read_bioset);
+
+	bio->bi_end_io = bch2_direct_IO_read_endio;
+
+	dio = container_of(bio, struct dio_read, rbio.bio);
+	closure_init(&dio->cl, NULL);
+
+	/*
+	 * this is a _really_ horrible hack just to avoid an atomic sub at the
+	 * end:
+	 */
+	if (!sync) {
+		set_closure_fn(&dio->cl, bch2_dio_read_complete, NULL);
+		atomic_set(&dio->cl.remaining,
+			   CLOSURE_REMAINING_INITIALIZER -
+			   CLOSURE_RUNNING +
+			   CLOSURE_DESTRUCTOR);
+	} else {
+		atomic_set(&dio->cl.remaining,
+			   CLOSURE_REMAINING_INITIALIZER + 1);
+	}
+
+	dio->req	= req;
+	dio->ret	= ret;
+	/*
+	 * This is one of the sketchier things I've encountered: we have to skip
+	 * the dirtying of requests that are internal from the kernel (i.e. from
+	 * loopback), because we'll deadlock on page_lock.
+	 */
+	dio->should_dirty = iter_is_iovec(iter);
+
+	goto start;
+	while (iter->count) {
+		bio = bio_alloc_bioset(NULL,
+				       bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
+				       REQ_OP_READ,
+				       GFP_KERNEL,
+				       &c->bio_read);
+		bio->bi_end_io		= bch2_direct_IO_read_split_endio;
+start:
+		bio->bi_opf		= REQ_OP_READ|REQ_SYNC;
+		bio->bi_iter.bi_sector	= offset >> 9;
+		bio->bi_private		= dio;
+
+		ret = bio_iov_iter_get_pages(bio, iter);
+		if (ret < 0) {
+			/* XXX: fault inject this path */
+			bio->bi_status = BLK_STS_RESOURCE;
+			bio_endio(bio);
+			break;
+		}
+
+		offset += bio->bi_iter.bi_size;
+
+		if (dio->should_dirty)
+			bio_set_pages_dirty(bio);
+
+		if (iter->count)
+			closure_get(&dio->cl);
+
+		bch2_read(c, rbio_init(bio, opts), inode_inum(inode));
+	}
+
+	iter->count += shorten;
+
+	if (sync) {
+		closure_sync(&dio->cl);
+		closure_debug_destroy(&dio->cl);
+		ret = dio->ret;
+		bio_check_or_release(&dio->rbio.bio, dio->should_dirty);
+		return ret;
+	} else {
+		return -EIOCBQUEUED;
+	}
+}
+
+ssize_t bch2_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct file *file = iocb->ki_filp;
+	struct bch_inode_info *inode = file_bch_inode(file);
+	struct address_space *mapping = file->f_mapping;
+	size_t count = iov_iter_count(iter);
+	ssize_t ret;
+
+	if (!count)
+		return 0; /* skip atime */
+
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		struct blk_plug plug;
+
+		if (unlikely(mapping->nrpages)) {
+			ret = filemap_write_and_wait_range(mapping,
+						iocb->ki_pos,
+						iocb->ki_pos + count - 1);
+			if (ret < 0)
+				goto out;
+		}
+
+		file_accessed(file);
+
+		blk_start_plug(&plug);
+		ret = bch2_direct_IO_read(iocb, iter);
+		blk_finish_plug(&plug);
+
+		if (ret >= 0)
+			iocb->ki_pos += ret;
+	} else {
+		bch2_pagecache_add_get(inode);
+		ret = generic_file_read_iter(iocb, iter);
+		bch2_pagecache_add_put(inode);
+	}
+out:
+	return bch2_err_class(ret);
+}
+
+/* O_DIRECT writes */
+
+struct dio_write {
+	struct kiocb			*req;
+	struct address_space		*mapping;
+	struct bch_inode_info		*inode;
+	struct mm_struct		*mm;
+	unsigned			loop:1,
+					extending:1,
+					sync:1,
+					flush:1,
+					free_iov:1;
+	struct quota_res		quota_res;
+	u64				written;
+
+	struct iov_iter			iter;
+	struct iovec			inline_vecs[2];
+
+	/* must be last: */
+	struct bch_write_op		op;
+};
+
+static bool bch2_check_range_allocated(struct bch_fs *c, subvol_inum inum,
+				       u64 offset, u64 size,
+				       unsigned nr_replicas, bool compressed)
+{
+	struct btree_trans trans;
+	struct btree_iter iter;
+	struct bkey_s_c k;
+	u64 end = offset + size;
+	u32 snapshot;
+	bool ret = true;
+	int err;
+
+	bch2_trans_init(&trans, c, 0, 0);
+retry:
+	bch2_trans_begin(&trans);
+
+	err = bch2_subvolume_get_snapshot(&trans, inum.subvol, &snapshot);
+	if (err)
+		goto err;
+
+	for_each_btree_key_norestart(&trans, iter, BTREE_ID_extents,
+			   SPOS(inum.inum, offset, snapshot),
+			   BTREE_ITER_SLOTS, k, err) {
+		if (bkey_ge(bkey_start_pos(k.k), POS(inum.inum, end)))
+			break;
+
+		if (k.k->p.snapshot != snapshot ||
+		    nr_replicas > bch2_bkey_replicas(c, k) ||
+		    (!compressed && bch2_bkey_sectors_compressed(k))) {
+			ret = false;
+			break;
+		}
+	}
+
+	offset = iter.pos.offset;
+	bch2_trans_iter_exit(&trans, &iter);
+err:
+	if (bch2_err_matches(err, BCH_ERR_transaction_restart))
+		goto retry;
+	bch2_trans_exit(&trans);
+
+	return err ? false : ret;
+}
+
+static noinline bool bch2_dio_write_check_allocated(struct dio_write *dio)
+{
+	struct bch_fs *c = dio->op.c;
+	struct bch_inode_info *inode = dio->inode;
+	struct bio *bio = &dio->op.wbio.bio;
+
+	return bch2_check_range_allocated(c, inode_inum(inode),
+				dio->op.pos.offset, bio_sectors(bio),
+				dio->op.opts.data_replicas,
+				dio->op.opts.compression != 0);
+}
+
+static void bch2_dio_write_loop_async(struct bch_write_op *);
+static __always_inline long bch2_dio_write_done(struct dio_write *dio);
+
+/*
+ * We're going to return -EIOCBQUEUED, but we haven't finished consuming the
+ * iov_iter yet, so we need to stash a copy of the iovec: it might be on the
+ * caller's stack, we're not guaranteed that it will live for the duration of
+ * the IO:
+ */
+static noinline int bch2_dio_write_copy_iov(struct dio_write *dio)
+{
+	struct iovec *iov = dio->inline_vecs;
+
+	/*
+	 * iov_iter has a single embedded iovec - nothing to do:
+	 */
+	if (iter_is_ubuf(&dio->iter))
+		return 0;
+
+	/*
+	 * We don't currently handle non-iovec iov_iters here - return an error,
+	 * and we'll fall back to doing the IO synchronously:
+	 */
+	if (!iter_is_iovec(&dio->iter))
+		return -1;
+
+	if (dio->iter.nr_segs > ARRAY_SIZE(dio->inline_vecs)) {
+		iov = kmalloc_array(dio->iter.nr_segs, sizeof(*iov),
+				    GFP_KERNEL);
+		if (unlikely(!iov))
+			return -ENOMEM;
+
+		dio->free_iov = true;
+	}
+
+	memcpy(iov, dio->iter.__iov, dio->iter.nr_segs * sizeof(*iov));
+	dio->iter.__iov = iov;
+	return 0;
+}
+
+static void bch2_dio_write_flush_done(struct closure *cl)
+{
+	struct dio_write *dio = container_of(cl, struct dio_write, op.cl);
+	struct bch_fs *c = dio->op.c;
+
+	closure_debug_destroy(cl);
+
+	dio->op.error = bch2_journal_error(&c->journal);
+
+	bch2_dio_write_done(dio);
+}
+
+static noinline void bch2_dio_write_flush(struct dio_write *dio)
+{
+	struct bch_fs *c = dio->op.c;
+	struct bch_inode_unpacked inode;
+	int ret;
+
+	dio->flush = 0;
+
+	closure_init(&dio->op.cl, NULL);
+
+	if (!dio->op.error) {
+		ret = bch2_inode_find_by_inum(c, inode_inum(dio->inode), &inode);
+		if (ret) {
+			dio->op.error = ret;
+		} else {
+			bch2_journal_flush_seq_async(&c->journal, inode.bi_journal_seq,
+						     &dio->op.cl);
+			bch2_inode_flush_nocow_writes_async(c, dio->inode, &dio->op.cl);
+		}
+	}
+
+	if (dio->sync) {
+		closure_sync(&dio->op.cl);
+		closure_debug_destroy(&dio->op.cl);
+	} else {
+		continue_at(&dio->op.cl, bch2_dio_write_flush_done, NULL);
+	}
+}
+
+static __always_inline long bch2_dio_write_done(struct dio_write *dio)
+{
+	struct kiocb *req = dio->req;
+	struct bch_inode_info *inode = dio->inode;
+	bool sync = dio->sync;
+	long ret;
+
+	if (unlikely(dio->flush)) {
+		bch2_dio_write_flush(dio);
+		if (!sync)
+			return -EIOCBQUEUED;
+	}
+
+	bch2_pagecache_block_put(inode);
+
+	if (dio->free_iov)
+		kfree(dio->iter.__iov);
+
+	ret = dio->op.error ?: ((long) dio->written << 9);
+	bio_put(&dio->op.wbio.bio);
+
+	/* inode->i_dio_count is our ref on inode and thus bch_fs */
+	inode_dio_end(&inode->v);
+
+	if (ret < 0)
+		ret = bch2_err_class(ret);
+
+	if (!sync) {
+		req->ki_complete(req, ret);
+		ret = -EIOCBQUEUED;
+	}
+	return ret;
+}
+
+static __always_inline void bch2_dio_write_end(struct dio_write *dio)
+{
+	struct bch_fs *c = dio->op.c;
+	struct kiocb *req = dio->req;
+	struct bch_inode_info *inode = dio->inode;
+	struct bio *bio = &dio->op.wbio.bio;
+
+	req->ki_pos	+= (u64) dio->op.written << 9;
+	dio->written	+= dio->op.written;
+
+	if (dio->extending) {
+		spin_lock(&inode->v.i_lock);
+		if (req->ki_pos > inode->v.i_size)
+			i_size_write(&inode->v, req->ki_pos);
+		spin_unlock(&inode->v.i_lock);
+	}
+
+	if (dio->op.i_sectors_delta || dio->quota_res.sectors) {
+		mutex_lock(&inode->ei_quota_lock);
+		__bch2_i_sectors_acct(c, inode, &dio->quota_res, dio->op.i_sectors_delta);
+		__bch2_quota_reservation_put(c, inode, &dio->quota_res);
+		mutex_unlock(&inode->ei_quota_lock);
+	}
+
+	bio_release_pages(bio, false);
+
+	if (unlikely(dio->op.error))
+		set_bit(EI_INODE_ERROR, &inode->ei_flags);
+}
+
+static __always_inline long bch2_dio_write_loop(struct dio_write *dio)
+{
+	struct bch_fs *c = dio->op.c;
+	struct kiocb *req = dio->req;
+	struct address_space *mapping = dio->mapping;
+	struct bch_inode_info *inode = dio->inode;
+	struct bch_io_opts opts;
+	struct bio *bio = &dio->op.wbio.bio;
+	unsigned unaligned, iter_count;
+	bool sync = dio->sync, dropped_locks;
+	long ret;
+
+	bch2_inode_opts_get(&opts, c, &inode->ei_inode);
+
+	while (1) {
+		iter_count = dio->iter.count;
+
+		EBUG_ON(current->faults_disabled_mapping);
+		current->faults_disabled_mapping = mapping;
+
+		ret = bio_iov_iter_get_pages(bio, &dio->iter);
+
+		dropped_locks = fdm_dropped_locks();
+
+		current->faults_disabled_mapping = NULL;
+
+		/*
+		 * If the fault handler returned an error but also signalled
+		 * that it dropped & retook ei_pagecache_lock, we just need to
+		 * re-shoot down the page cache and retry:
+		 */
+		if (dropped_locks && ret)
+			ret = 0;
+
+		if (unlikely(ret < 0))
+			goto err;
+
+		if (unlikely(dropped_locks)) {
+			ret = bch2_write_invalidate_inode_pages_range(mapping,
+					req->ki_pos,
+					req->ki_pos + iter_count - 1);
+			if (unlikely(ret))
+				goto err;
+
+			if (!bio->bi_iter.bi_size)
+				continue;
+		}
+
+		unaligned = bio->bi_iter.bi_size & (block_bytes(c) - 1);
+		bio->bi_iter.bi_size -= unaligned;
+		iov_iter_revert(&dio->iter, unaligned);
+
+		if (!bio->bi_iter.bi_size) {
+			/*
+			 * bio_iov_iter_get_pages was only able to get <
+			 * blocksize worth of pages:
+			 */
+			ret = -EFAULT;
+			goto err;
+		}
+
+		bch2_write_op_init(&dio->op, c, opts);
+		dio->op.end_io		= sync
+			? NULL
+			: bch2_dio_write_loop_async;
+		dio->op.target		= dio->op.opts.foreground_target;
+		dio->op.write_point	= writepoint_hashed((unsigned long) current);
+		dio->op.nr_replicas	= dio->op.opts.data_replicas;
+		dio->op.subvol		= inode->ei_subvol;
+		dio->op.pos		= POS(inode->v.i_ino, (u64) req->ki_pos >> 9);
+		dio->op.devs_need_flush	= &inode->ei_devs_need_flush;
+
+		if (sync)
+			dio->op.flags |= BCH_WRITE_SYNC;
+		dio->op.flags |= BCH_WRITE_CHECK_ENOSPC;
+
+		ret = bch2_quota_reservation_add(c, inode, &dio->quota_res,
+						 bio_sectors(bio), true);
+		if (unlikely(ret))
+			goto err;
+
+		ret = bch2_disk_reservation_get(c, &dio->op.res, bio_sectors(bio),
+						dio->op.opts.data_replicas, 0);
+		if (unlikely(ret) &&
+		    !bch2_dio_write_check_allocated(dio))
+			goto err;
+
+		task_io_account_write(bio->bi_iter.bi_size);
+
+		if (unlikely(dio->iter.count) &&
+		    !dio->sync &&
+		    !dio->loop &&
+		    bch2_dio_write_copy_iov(dio))
+			dio->sync = sync = true;
+
+		dio->loop = true;
+		closure_call(&dio->op.cl, bch2_write, NULL, NULL);
+
+		if (!sync)
+			return -EIOCBQUEUED;
+
+		bch2_dio_write_end(dio);
+
+		if (likely(!dio->iter.count) || dio->op.error)
+			break;
+
+		bio_reset(bio, NULL, REQ_OP_WRITE);
+	}
+out:
+	return bch2_dio_write_done(dio);
+err:
+	dio->op.error = ret;
+
+	bio_release_pages(bio, false);
+
+	bch2_quota_reservation_put(c, inode, &dio->quota_res);
+	goto out;
+}
+
+static noinline __cold void bch2_dio_write_continue(struct dio_write *dio)
+{
+	struct mm_struct *mm = dio->mm;
+
+	bio_reset(&dio->op.wbio.bio, NULL, REQ_OP_WRITE);
+
+	if (mm)
+		kthread_use_mm(mm);
+	bch2_dio_write_loop(dio);
+	if (mm)
+		kthread_unuse_mm(mm);
+}
+
+static void bch2_dio_write_loop_async(struct bch_write_op *op)
+{
+	struct dio_write *dio = container_of(op, struct dio_write, op);
+
+	bch2_dio_write_end(dio);
+
+	if (likely(!dio->iter.count) || dio->op.error)
+		bch2_dio_write_done(dio);
+	else
+		bch2_dio_write_continue(dio);
+}
+
+ssize_t bch2_direct_write(struct kiocb *req, struct iov_iter *iter)
+{
+	struct file *file = req->ki_filp;
+	struct address_space *mapping = file->f_mapping;
+	struct bch_inode_info *inode = file_bch_inode(file);
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct dio_write *dio;
+	struct bio *bio;
+	bool locked = true, extending;
+	ssize_t ret;
+
+	prefetch(&c->opts);
+	prefetch((void *) &c->opts + 64);
+	prefetch(&inode->ei_inode);
+	prefetch((void *) &inode->ei_inode + 64);
+
+	inode_lock(&inode->v);
+
+	ret = generic_write_checks(req, iter);
+	if (unlikely(ret <= 0))
+		goto err;
+
+	ret = file_remove_privs(file);
+	if (unlikely(ret))
+		goto err;
+
+	ret = file_update_time(file);
+	if (unlikely(ret))
+		goto err;
+
+	if (unlikely((req->ki_pos|iter->count) & (block_bytes(c) - 1)))
+		goto err;
+
+	inode_dio_begin(&inode->v);
+	bch2_pagecache_block_get(inode);
+
+	extending = req->ki_pos + iter->count > inode->v.i_size;
+	if (!extending) {
+		inode_unlock(&inode->v);
+		locked = false;
+	}
+
+	bio = bio_alloc_bioset(NULL,
+			       bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
+			       REQ_OP_WRITE,
+			       GFP_KERNEL,
+			       &c->dio_write_bioset);
+	dio = container_of(bio, struct dio_write, op.wbio.bio);
+	dio->req		= req;
+	dio->mapping		= mapping;
+	dio->inode		= inode;
+	dio->mm			= current->mm;
+	dio->loop		= false;
+	dio->extending		= extending;
+	dio->sync		= is_sync_kiocb(req) || extending;
+	dio->flush		= iocb_is_dsync(req) && !c->opts.journal_flush_disabled;
+	dio->free_iov		= false;
+	dio->quota_res.sectors	= 0;
+	dio->written		= 0;
+	dio->iter		= *iter;
+	dio->op.c		= c;
+
+	if (unlikely(mapping->nrpages)) {
+		ret = bch2_write_invalidate_inode_pages_range(mapping,
+						req->ki_pos,
+						req->ki_pos + iter->count - 1);
+		if (unlikely(ret))
+			goto err_put_bio;
+	}
+
+	ret = bch2_dio_write_loop(dio);
+err:
+	if (locked)
+		inode_unlock(&inode->v);
+	return ret;
+err_put_bio:
+	bch2_pagecache_block_put(inode);
+	bio_put(bio);
+	inode_dio_end(&inode->v);
+	goto err;
+}
+
+void bch2_fs_fs_io_direct_exit(struct bch_fs *c)
+{
+	bioset_exit(&c->dio_write_bioset);
+	bioset_exit(&c->dio_read_bioset);
+}
+
+int bch2_fs_fs_io_direct_init(struct bch_fs *c)
+{
+	if (bioset_init(&c->dio_read_bioset,
+			4, offsetof(struct dio_read, rbio.bio),
+			BIOSET_NEED_BVECS))
+		return -BCH_ERR_ENOMEM_dio_read_bioset_init;
+
+	if (bioset_init(&c->dio_write_bioset,
+			4, offsetof(struct dio_write, op.wbio.bio),
+			BIOSET_NEED_BVECS))
+		return -BCH_ERR_ENOMEM_dio_write_bioset_init;
+
+	return 0;
+}
+
+#endif /* NO_BCACHEFS_FS */

fs/bcachefs/fs-io-direct.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_FS_IO_DIRECT_H
+#define _BCACHEFS_FS_IO_DIRECT_H
+
+#ifndef NO_BCACHEFS_FS
+ssize_t bch2_direct_write(struct kiocb *, struct iov_iter *);
+ssize_t bch2_read_iter(struct kiocb *, struct iov_iter *);
+
+void bch2_fs_fs_io_direct_exit(struct bch_fs *);
+int bch2_fs_fs_io_direct_init(struct bch_fs *);
+#else
+static inline void bch2_fs_fs_io_direct_exit(struct bch_fs *c) {}
+static inline int bch2_fs_fs_io_direct_init(struct bch_fs *c) { return 0; }
+#endif
+
+#endif /* _BCACHEFS_FS_IO_DIRECT_H */

fs/bcachefs/fs-io-pagecache.c

···
+// SPDX-License-Identifier: GPL-2.0
+#ifndef NO_BCACHEFS_FS
+
+#include "bcachefs.h"
+#include "btree_iter.h"
+#include "extents.h"
+#include "fs-io.h"
+#include "fs-io-pagecache.h"
+#include "subvolume.h"
+
+#include <linux/pagevec.h>
+#include <linux/writeback.h>
+
+int bch2_filemap_get_contig_folios_d(struct address_space *mapping,
+				     loff_t start, u64 end,
+				     int fgp_flags, gfp_t gfp,
+				     folios *folios)
+{
+	struct folio *f;
+	u64 pos = start;
+	int ret = 0;
+
+	while (pos < end) {
+		if ((u64) pos >= (u64) start + (1ULL << 20))
+			fgp_flags &= ~FGP_CREAT;
+
+		ret = darray_make_room_gfp(folios, 1, gfp & GFP_KERNEL);
+		if (ret)
+			break;
+
+		f = __filemap_get_folio(mapping, pos >> PAGE_SHIFT, fgp_flags, gfp);
+		if (IS_ERR_OR_NULL(f))
+			break;
+
+		BUG_ON(folios->nr && folio_pos(f) != pos);
+
+		pos = folio_end_pos(f);
+		darray_push(folios, f);
+	}
+
+	if (!folios->nr && !ret && (fgp_flags & FGP_CREAT))
+		ret = -ENOMEM;
+
+	return folios->nr ? 0 : ret;
+}
+
+/* pagecache_block must be held */
+int bch2_write_invalidate_inode_pages_range(struct address_space *mapping,
+					    loff_t start, loff_t end)
+{
+	int ret;
+
+	/*
+	 * XXX: the way this is currently implemented, we can spin if a process
+	 * is continually redirtying a specific page
+	 */
+	do {
+		if (!mapping->nrpages)
+			return 0;
+
+		ret = filemap_write_and_wait_range(mapping, start, end);
+		if (ret)
+			break;
+
+		if (!mapping->nrpages)
+			return 0;
+
+		ret = invalidate_inode_pages2_range(mapping,
+				start >> PAGE_SHIFT,
+				end >> PAGE_SHIFT);
+	} while (ret == -EBUSY);
+
+	return ret;
+}
+
+static const char * const bch2_folio_sector_states[] = {
+#define x(n)	#n,
+	BCH_FOLIO_SECTOR_STATE()
+#undef x
+	NULL
+};
+
+static inline enum bch_folio_sector_state
+folio_sector_dirty(enum bch_folio_sector_state state)
+{
+	switch (state) {
+	case SECTOR_unallocated:
+		return SECTOR_dirty;
+	case SECTOR_reserved:
+		return SECTOR_dirty_reserved;
+	default:
+		return state;
+	}
+}
+
+static inline enum bch_folio_sector_state
+folio_sector_undirty(enum bch_folio_sector_state state)
+{
+	switch (state) {
+	case SECTOR_dirty:
+		return SECTOR_unallocated;
+	case SECTOR_dirty_reserved:
+		return SECTOR_reserved;
+	default:
+		return state;
+	}
+}
+
+static inline enum bch_folio_sector_state
+folio_sector_reserve(enum bch_folio_sector_state state)
+{
+	switch (state) {
+	case SECTOR_unallocated:
+		return SECTOR_reserved;
+	case SECTOR_dirty:
+		return SECTOR_dirty_reserved;
+	default:
+		return state;
+	}
+}
+
+/* for newly allocated folios: */
+struct bch_folio *__bch2_folio_create(struct folio *folio, gfp_t gfp)
+{
+	struct bch_folio *s;
+
+	s = kzalloc(sizeof(*s) +
+		    sizeof(struct bch_folio_sector) *
+		    folio_sectors(folio), gfp);
+	if (!s)
+		return NULL;
+
+	spin_lock_init(&s->lock);
+	folio_attach_private(folio, s);
+	return s;
+}
+
+struct bch_folio *bch2_folio_create(struct folio *folio, gfp_t gfp)
+{
+	return bch2_folio(folio) ?: __bch2_folio_create(folio, gfp);
+}
+
+static unsigned bkey_to_sector_state(struct bkey_s_c k)
+{
+	if (bkey_extent_is_reservation(k))
+		return SECTOR_reserved;
+	if (bkey_extent_is_allocation(k.k))
+		return SECTOR_allocated;
+	return SECTOR_unallocated;
+}
+
+static void __bch2_folio_set(struct folio *folio,
+			     unsigned pg_offset, unsigned pg_len,
+			     unsigned nr_ptrs, unsigned state)
+{
+	struct bch_folio *s = bch2_folio(folio);
+	unsigned i, sectors = folio_sectors(folio);
+
+	BUG_ON(pg_offset >= sectors);
+	BUG_ON(pg_offset + pg_len > sectors);
+
+	spin_lock(&s->lock);
+
+	for (i = pg_offset; i < pg_offset + pg_len; i++) {
+		s->s[i].nr_replicas	= nr_ptrs;
+		bch2_folio_sector_set(folio, s, i, state);
+	}
+
+	if (i == sectors)
+		s->uptodate = true;
+
+	spin_unlock(&s->lock);
+}
+
+/*
+ * Initialize bch_folio state (allocated/unallocated, nr_replicas) from the
+ * extents btree:
+ */
+int bch2_folio_set(struct bch_fs *c, subvol_inum inum,
+		   struct folio **folios, unsigned nr_folios)
+{
+	struct btree_trans trans;
+	struct btree_iter iter;
+	struct bkey_s_c k;
+	struct bch_folio *s;
+	u64 offset = folio_sector(folios[0]);
+	unsigned folio_idx;
+	u32 snapshot;
+	bool need_set = false;
+	int ret;
+
+	for (folio_idx = 0; folio_idx < nr_folios; folio_idx++) {
+		s = bch2_folio_create(folios[folio_idx], GFP_KERNEL);
+		if (!s)
+			return -ENOMEM;
+
+		need_set |= !s->uptodate;
+	}
+
+	if (!need_set)
+		return 0;
+
+	folio_idx = 0;
+	bch2_trans_init(&trans, c, 0, 0);
+retry:
+	bch2_trans_begin(&trans);
+
+	ret = bch2_subvolume_get_snapshot(&trans, inum.subvol, &snapshot);
+	if (ret)
+		goto err;
+
+	for_each_btree_key_norestart(&trans, iter, BTREE_ID_extents,
+			   SPOS(inum.inum, offset, snapshot),
+			   BTREE_ITER_SLOTS, k, ret) {
+		unsigned nr_ptrs = bch2_bkey_nr_ptrs_fully_allocated(k);
+		unsigned state = bkey_to_sector_state(k);
+
+		while (folio_idx < nr_folios) {
+			struct folio *folio = folios[folio_idx];
+			u64 folio_start	= folio_sector(folio);
+			u64 folio_end	= folio_end_sector(folio);
+			unsigned folio_offset = max(bkey_start_offset(k.k), folio_start) -
+				folio_start;
+			unsigned folio_len = min(k.k->p.offset, folio_end) -
+				folio_offset - folio_start;
+
+			BUG_ON(k.k->p.offset < folio_start);
+			BUG_ON(bkey_start_offset(k.k) > folio_end);
+
+			if (!bch2_folio(folio)->uptodate)
+				__bch2_folio_set(folio, folio_offset, folio_len, nr_ptrs, state);
+
+			if (k.k->p.offset < folio_end)
+				break;
+			folio_idx++;
+		}
+
+		if (folio_idx == nr_folios)
+			break;
+	}
+
+	offset = iter.pos.offset;
+	bch2_trans_iter_exit(&trans, &iter);
+err:
+	if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+		goto retry;
+	bch2_trans_exit(&trans);
+
+	return ret;
+}
+
+void bch2_bio_page_state_set(struct bio *bio, struct bkey_s_c k)
+{
+	struct bvec_iter iter;
+	struct folio_vec fv;
+	unsigned nr_ptrs = k.k->type == KEY_TYPE_reflink_v
+		? 0 : bch2_bkey_nr_ptrs_fully_allocated(k);
+	unsigned state = bkey_to_sector_state(k);
+
+	bio_for_each_folio(fv, bio, iter)
+		__bch2_folio_set(fv.fv_folio,
+				 fv.fv_offset >> 9,
+				 fv.fv_len >> 9,
+				 nr_ptrs, state);
+}
+
+void bch2_mark_pagecache_unallocated(struct bch_inode_info *inode,
+				     u64 start, u64 end)
+{
+	pgoff_t index = start >> PAGE_SECTORS_SHIFT;
+	pgoff_t end_index = (end - 1) >> PAGE_SECTORS_SHIFT;
+	struct folio_batch fbatch;
+	unsigned i, j;
+
+	if (end <= start)
+		return;
+
+	folio_batch_init(&fbatch);
+
+	while (filemap_get_folios(inode->v.i_mapping,
+				  &index, end_index, &fbatch)) {
+		for (i = 0; i < folio_batch_count(&fbatch); i++) {
+			struct folio *folio = fbatch.folios[i];
+			u64 folio_start = folio_sector(folio);
+			u64 folio_end = folio_end_sector(folio);
+			unsigned folio_offset = max(start, folio_start) - folio_start;
+			unsigned folio_len = min(end, folio_end) - folio_offset - folio_start;
+			struct bch_folio *s;
+
+			BUG_ON(end <= folio_start);
+
+			folio_lock(folio);
+			s = bch2_folio(folio);
+
+			if (s) {
+				spin_lock(&s->lock);
+				for (j = folio_offset; j < folio_offset + folio_len; j++)
+					s->s[j].nr_replicas = 0;
+				spin_unlock(&s->lock);
+			}
+
+			folio_unlock(folio);
+		}
+		folio_batch_release(&fbatch);
+		cond_resched();
+	}
+}
+
+void bch2_mark_pagecache_reserved(struct bch_inode_info *inode,
+				  u64 start, u64 end)
+{
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	pgoff_t index = start >> PAGE_SECTORS_SHIFT;
+	pgoff_t end_index = (end - 1) >> PAGE_SECTORS_SHIFT;
+	struct folio_batch fbatch;
+	s64 i_sectors_delta = 0;
+	unsigned i, j;
+
+	if (end <= start)
+		return;
+
+	folio_batch_init(&fbatch);
+
+	while (filemap_get_folios(inode->v.i_mapping,
+				  &index, end_index, &fbatch)) {
+		for (i = 0; i < folio_batch_count(&fbatch); i++) {
+			struct folio *folio = fbatch.folios[i];
+			u64 folio_start = folio_sector(folio);
+			u64 folio_end = folio_end_sector(folio);
+			unsigned folio_offset = max(start, folio_start) - folio_start;
+			unsigned folio_len = min(end, folio_end) - folio_offset - folio_start;
+			struct bch_folio *s;
+
+			BUG_ON(end <= folio_start);
+
+			folio_lock(folio);
+			s = bch2_folio(folio);
+
+			if (s) {
+				spin_lock(&s->lock);
+				for (j = folio_offset; j < folio_offset + folio_len; j++) {
+					i_sectors_delta -= s->s[j].state == SECTOR_dirty;
+					bch2_folio_sector_set(folio, s, j,
+						folio_sector_reserve(s->s[j].state));
+				}
+				spin_unlock(&s->lock);
+			}
+
+			folio_unlock(folio);
+		}
+		folio_batch_release(&fbatch);
+		cond_resched();
+	}
+
+	bch2_i_sectors_acct(c, inode, NULL, i_sectors_delta);
+}
+
+static inline unsigned sectors_to_reserve(struct bch_folio_sector *s,
+					  unsigned nr_replicas)
+{
+	return max(0, (int) nr_replicas -
+		   s->nr_replicas -
+		   s->replicas_reserved);
+}
+
+int bch2_get_folio_disk_reservation(struct bch_fs *c,
+				struct bch_inode_info *inode,
+				struct folio *folio, bool check_enospc)
+{
+	struct bch_folio *s = bch2_folio_create(folio, 0);
+	unsigned nr_replicas = inode_nr_replicas(c, inode);
+	struct disk_reservation disk_res = { 0 };
+	unsigned i, sectors = folio_sectors(folio), disk_res_sectors = 0;
+	int ret;
+
+	if (!s)
+		return -ENOMEM;
+
+	for (i = 0; i < sectors; i++)
+		disk_res_sectors += sectors_to_reserve(&s->s[i], nr_replicas);
+
+	if (!disk_res_sectors)
+		return 0;
+
+	ret = bch2_disk_reservation_get(c, &disk_res,
+					disk_res_sectors, 1,
+					!check_enospc
+					? BCH_DISK_RESERVATION_NOFAIL
+					: 0);
+	if (unlikely(ret))
+		return ret;
+
+	for (i = 0; i < sectors; i++)
+		s->s[i].replicas_reserved +=
+			sectors_to_reserve(&s->s[i], nr_replicas);
+
+	return 0;
+}
+
+void bch2_folio_reservation_put(struct bch_fs *c,
+			struct bch_inode_info *inode,
+			struct bch2_folio_reservation *res)
+{
+	bch2_disk_reservation_put(c, &res->disk);
+	bch2_quota_reservation_put(c, inode, &res->quota);
+}
+
+int bch2_folio_reservation_get(struct bch_fs *c,
+			struct bch_inode_info *inode,
+			struct folio *folio,
+			struct bch2_folio_reservation *res,
+			unsigned offset, unsigned len)
+{
+	struct bch_folio *s = bch2_folio_create(folio, 0);
+	unsigned i, disk_sectors = 0, quota_sectors = 0;
+	int ret;
+
+	if (!s)
+		return -ENOMEM;
+
+	BUG_ON(!s->uptodate);
+
+	for (i = round_down(offset, block_bytes(c)) >> 9;
+	     i < round_up(offset + len, block_bytes(c)) >> 9;
+	     i++) {
+		disk_sectors += sectors_to_reserve(&s->s[i],
+						res->disk.nr_replicas);
+		quota_sectors += s->s[i].state == SECTOR_unallocated;
+	}
+
+	if (disk_sectors) {
+		ret = bch2_disk_reservation_add(c, &res->disk, disk_sectors, 0);
+		if (unlikely(ret))
+			return ret;
+	}
+
+	if (quota_sectors) {
+		ret = bch2_quota_reservation_add(c, inode, &res->quota,
+						 quota_sectors, true);
+		if (unlikely(ret)) {
+			struct disk_reservation tmp = {
+				.sectors = disk_sectors
+			};
+
+			bch2_disk_reservation_put(c, &tmp);
+			res->disk.sectors -= disk_sectors;
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static void bch2_clear_folio_bits(struct folio *folio)
+{
+	struct bch_inode_info *inode = to_bch_ei(folio->mapping->host);
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct bch_folio *s = bch2_folio(folio);
+	struct disk_reservation disk_res = { 0 };
+	int i, sectors = folio_sectors(folio), dirty_sectors = 0;
+
+	if (!s)
+		return;
+
+	EBUG_ON(!folio_test_locked(folio));
+	EBUG_ON(folio_test_writeback(folio));
+
+	for (i = 0; i < sectors; i++) {
+		disk_res.sectors += s->s[i].replicas_reserved;
+		s->s[i].replicas_reserved = 0;
+
+		dirty_sectors -= s->s[i].state == SECTOR_dirty;
+		bch2_folio_sector_set(folio, s, i, folio_sector_undirty(s->s[i].state));
+	}
+
+	bch2_disk_reservation_put(c, &disk_res);
+
+	bch2_i_sectors_acct(c, inode, NULL, dirty_sectors);
+
+	bch2_folio_release(folio);
+}
+
+void bch2_set_folio_dirty(struct bch_fs *c,
+			  struct bch_inode_info *inode,
+			  struct folio *folio,
+			  struct bch2_folio_reservation *res,
+			  unsigned offset, unsigned len)
+{
+	struct bch_folio *s = bch2_folio(folio);
+	unsigned i, dirty_sectors = 0;
+
+	WARN_ON((u64) folio_pos(folio) + offset + len >
+		round_up((u64) i_size_read(&inode->v), block_bytes(c)));
+
+	BUG_ON(!s->uptodate);
+
+	spin_lock(&s->lock);
+
+	for (i = round_down(offset, block_bytes(c)) >> 9;
+	     i < round_up(offset + len, block_bytes(c)) >> 9;
+	     i++) {
+		unsigned sectors = sectors_to_reserve(&s->s[i],
+						res->disk.nr_replicas);
+
+		/*
+		 * This can happen if we race with the error path in
+		 * bch2_writepage_io_done():
+		 */
+		sectors = min_t(unsigned, sectors, res->disk.sectors);
+
+		s->s[i].replicas_reserved += sectors;
+		res->disk.sectors -= sectors;
+
+		dirty_sectors += s->s[i].state == SECTOR_unallocated;
+
+		bch2_folio_sector_set(folio, s, i, folio_sector_dirty(s->s[i].state));
+	}
+
+	spin_unlock(&s->lock);
+
+	bch2_i_sectors_acct(c, inode, &res->quota, dirty_sectors);
+
+	if (!folio_test_dirty(folio))
+		filemap_dirty_folio(inode->v.i_mapping, folio);
+}
+
+vm_fault_t bch2_page_fault(struct vm_fault *vmf)
+{
+	struct file *file = vmf->vma->vm_file;
+	struct address_space *mapping = file->f_mapping;
+	struct address_space *fdm = faults_disabled_mapping();
+	struct bch_inode_info *inode = file_bch_inode(file);
+	vm_fault_t ret;
+
+	if (fdm == mapping)
+		return VM_FAULT_SIGBUS;
+
+	/* Lock ordering: */
+	if (fdm > mapping) {
+		struct bch_inode_info *fdm_host = to_bch_ei(fdm->host);
+
+		if (bch2_pagecache_add_tryget(inode))
+			goto got_lock;
+
+		bch2_pagecache_block_put(fdm_host);
+
+		bch2_pagecache_add_get(inode);
+		bch2_pagecache_add_put(inode);
+
+		bch2_pagecache_block_get(fdm_host);
+
+		/* Signal that lock has been dropped: */
+		set_fdm_dropped_locks();
+		return VM_FAULT_SIGBUS;
+	}
+
+	bch2_pagecache_add_get(inode);
+got_lock:
+	ret = filemap_fault(vmf);
+	bch2_pagecache_add_put(inode);
+
+	return ret;
+}
+
+vm_fault_t bch2_page_mkwrite(struct vm_fault *vmf)
+{
+	struct folio *folio = page_folio(vmf->page);
+	struct file *file = vmf->vma->vm_file;
+	struct bch_inode_info *inode = file_bch_inode(file);
+	struct address_space *mapping = file->f_mapping;
+	struct bch_fs *c = inode->v.i_sb->s_fs_info;
+	struct bch2_folio_reservation res;
+	unsigned len;
+	loff_t isize;
+	vm_fault_t ret;
+
+	bch2_folio_reservation_init(c, inode, &res);
+
+	sb_start_pagefault(inode->v.i_sb);
+	file_update_time(file);
+
+	/*
+	 * Not strictly necessary, but helps avoid dio writes livelocking in
+	 * bch2_write_invalidate_inode_pages_range() - can drop this if/when we get
+	 * a bch2_write_invalidate_inode_pages_range() that works without dropping
+	 * page lock before invalidating page
+	 */
+	bch2_pagecache_add_get(inode);
+
+	folio_lock(folio);
+	isize = i_size_read(&inode->v);
+
+	if (folio->mapping != mapping || folio_pos(folio) >= isize) {
+		folio_unlock(folio);
+		ret = VM_FAULT_NOPAGE;
+		goto out;
+	}
+
+	len = min_t(loff_t, folio_size(folio), isize - folio_pos(folio));
+
+	if (bch2_folio_set(c, inode_inum(inode), &folio, 1) ?:
+	    bch2_folio_reservation_get(c, inode, folio, &res, 0, len)) {
+		folio_unlock(folio);
+		ret = VM_FAULT_SIGBUS;
+		goto out;
+	}
+
+	bch2_set_folio_dirty(c, inode, folio, &res, 0, len);
+	bch2_folio_reservation_put(c, inode, &res);
+
+	folio_wait_stable(folio);
+	ret = VM_FAULT_LOCKED;
+out:
+	bch2_pagecache_add_put(inode);
+	sb_end_pagefault(inode->v.i_sb);
+
+	return ret;
+}
+
+void bch2_invalidate_folio(struct folio *folio, size_t offset, size_t length)
+{
+	if (offset || length < folio_size(folio))
+		return;
+
+	bch2_clear_folio_bits(folio);
+}
+
+bool bch2_release_folio(struct folio *folio, gfp_t gfp_mask)
+{
+	if (folio_test_dirty(folio) || folio_test_writeback(folio))
+		return false;
+
+	bch2_clear_folio_bits(folio);
+	return true;
+}
+
+/* fseek: */
+
+static int folio_data_offset(struct folio *folio, loff_t pos,
+			     unsigned min_replicas)
+{
+	struct bch_folio *s = bch2_folio(folio);
+	unsigned i, sectors = folio_sectors(folio);
+
+	if (s)
+		for (i = folio_pos_to_s(folio, pos); i < sectors; i++)
+			if (s->s[i].state >= SECTOR_dirty &&
+			    s->s[i].nr_replicas + s->s[i].replicas_reserved >= min_replicas)
+				return i << SECTOR_SHIFT;
+
+	return -1;
+}
+
+loff_t bch2_seek_pagecache_data(struct inode *vinode,
+				loff_t start_offset,
+				loff_t end_offset,
+				unsigned min_replicas,
+				bool nonblock)
+{
+	struct folio_batch fbatch;
+	pgoff_t start_index	= start_offset >> PAGE_SHIFT;
+	pgoff_t end_index	= end_offset >> PAGE_SHIFT;
+	pgoff_t index		= start_index;
+	unsigned i;
+	loff_t ret;
+	int offset;
+
+	folio_batch_init(&fbatch);
+
+	while (filemap_get_folios(vinode->i_mapping,
+				  &index, end_index, &fbatch)) {
+		for (i = 0; i < folio_batch_count(&fbatch); i++) {
+			struct folio *folio = fbatch.folios[i];
+
+			if (!nonblock) {
+				folio_lock(folio);
+			} else if (!folio_trylock(folio)) {
+				folio_batch_release(&fbatch);
+				return -EAGAIN;
+			}
+
+			offset = folio_data_offset(folio,
+					max(folio_pos(folio), start_offset),
+					min_replicas);
+			if (offset >= 0) {
+				ret = clamp(folio_pos(folio) + offset,
+					    start_offset, end_offset);
+				folio_unlock(folio);
+				folio_batch_release(&fbatch);
+				return ret;
+			}
+			folio_unlock(folio);
+		}
+		folio_batch_release(&fbatch);
+		cond_resched();
+	}
+
+	return end_offset;
+}
+
+static int folio_hole_offset(struct address_space *mapping, loff_t *offset,
+			      unsigned min_replicas, bool nonblock)
+{
+	struct folio *folio;
+	struct bch_folio *s;
+	unsigned i, sectors;
+	bool ret = true;
+
+	folio = __filemap_get_folio(mapping, *offset >> PAGE_SHIFT,
+				    FGP_LOCK|(nonblock ? FGP_NOWAIT : 0), 0);
+	if (folio == ERR_PTR(-EAGAIN))
+		return -EAGAIN;
+	if (IS_ERR_OR_NULL(folio))
+		return true;
+
+	s = bch2_folio(folio);
+	if (!s)
+		goto unlock;
+
+	sectors = folio_sectors(folio);
+	for (i = folio_pos_to_s(folio, *offset); i < sectors; i++)
+		if (s->s[i].state < SECTOR_dirty ||
+		    s->s[i].nr_replicas + s->s[i].replicas_reserved < min_replicas) {
+			*offset = max(*offset,
+				      folio_pos(folio) + (i << SECTOR_SHIFT));
+			goto unlock;
+		}
+
+	*offset = folio_end_pos(folio);
+	ret = false;
+unlock:
+	folio_unlock(folio);
+	folio_put(folio);
+	return ret;
+}
+
+loff_t bch2_seek_pagecache_hole(struct inode *vinode,
+				loff_t start_offset,
+				loff_t end_offset,
+				unsigned min_replicas,
+				bool nonblock)
+{
+	struct address_space *mapping = vinode->i_mapping;
+	loff_t offset = start_offset;
+
+	while (offset < end_offset &&
+	       !folio_hole_offset(mapping, &offset, min_replicas, nonblock))
+		;
+
+	return min(offset, end_offset);
+}
+
+int bch2_clamp_data_hole(struct inode *inode,
+			 u64 *hole_start,
+			 u64 *hole_end,
+			 unsigned min_replicas,
+			 bool nonblock)
+{
+	loff_t ret;
+
+	ret = bch2_seek_pagecache_hole(inode,
+		*hole_start << 9, *hole_end << 9, min_replicas, nonblock) >> 9;
+	if (ret < 0)
+		return ret;
+
+	*hole_start = ret;
+
+	if (*hole_start == *hole_end)
+		return 0;
+
+	ret = bch2_seek_pagecache_data(inode,
+		*hole_start << 9, *hole_end << 9, min_replicas, nonblock) >> 9;
+	if (ret < 0)
+		return ret;
+
+	*hole_end = ret;
+	return 0;
+}
+
+#endif /* NO_BCACHEFS_FS */

fs/bcachefs/fs-io-pagecache.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_FS_IO_PAGECACHE_H
+#define _BCACHEFS_FS_IO_PAGECACHE_H
+
+#include <linux/pagemap.h>
+
+typedef DARRAY(struct folio *) folios;
+
+int bch2_filemap_get_contig_folios_d(struct address_space *, loff_t,
+				     u64, int, gfp_t, folios *);
+int bch2_write_invalidate_inode_pages_range(struct address_space *, loff_t, loff_t);
+
+/*
+ * Use u64 for the end pos and sector helpers because if the folio covers the
+ * max supported range of the mapping, the start offset of the next folio
+ * overflows loff_t. This breaks much of the range based processing in the
+ * buffered write path.
+ */
+static inline u64 folio_end_pos(struct folio *folio)
+{
+	return folio_pos(folio) + folio_size(folio);
+}
+
+static inline size_t folio_sectors(struct folio *folio)
+{
+	return PAGE_SECTORS << folio_order(folio);
+}
+
+static inline loff_t folio_sector(struct folio *folio)
+{
+	return folio_pos(folio) >> 9;
+}
+
+static inline u64 folio_end_sector(struct folio *folio)
+{
+	return folio_end_pos(folio) >> 9;
+}
+
+#define BCH_FOLIO_SECTOR_STATE()	\
+	x(unallocated)			\
+	x(reserved)			\
+	x(dirty)			\
+	x(dirty_reserved)		\
+	x(allocated)
+
+enum bch_folio_sector_state {
+#define x(n)	SECTOR_##n,
+	BCH_FOLIO_SECTOR_STATE()
+#undef x
+};
+
+struct bch_folio_sector {
+	/* Uncompressed, fully allocated replicas (or on disk reservation): */
+	unsigned		nr_replicas:4;
+
+	/* Owns PAGE_SECTORS * replicas_reserved sized in memory reservation: */
+	unsigned		replicas_reserved:4;
+
+	/* i_sectors: */
+	enum bch_folio_sector_state state:8;
+};
+
+struct bch_folio {
+	spinlock_t		lock;
+	atomic_t		write_count;
+	/*
+	 * Is the sector state up to date with the btree?
+	 * (Not the data itself)
+	 */
+	bool			uptodate;
+	struct bch_folio_sector	s[];
+};
+
+/* Helper for when we need to add debug instrumentation: */
+static inline void bch2_folio_sector_set(struct folio *folio,
+			     struct bch_folio *s,
+			     unsigned i, unsigned n)
+{
+	s->s[i].state = n;
+}
+
+/* file offset (to folio offset) to bch_folio_sector index */
+static inline int folio_pos_to_s(struct folio *folio, loff_t pos)
+{
+	u64 f_offset = pos - folio_pos(folio);
+
+	BUG_ON(pos < folio_pos(folio) || pos >= folio_end_pos(folio));
+	return f_offset >> SECTOR_SHIFT;
+}
+
+/* for newly allocated folios: */
+static inline void __bch2_folio_release(struct folio *folio)
+{
+	kfree(folio_detach_private(folio));
+}
+
+static inline void bch2_folio_release(struct folio *folio)
+{
+	EBUG_ON(!folio_test_locked(folio));
+	__bch2_folio_release(folio);
+}
+
+static inline struct bch_folio *__bch2_folio(struct folio *folio)
+{
+	return folio_has_private(folio)
+		? (struct bch_folio *) folio_get_private(folio)
+		: NULL;
+}
+
+static inline struct bch_folio *bch2_folio(struct folio *folio)
+{
+	EBUG_ON(!folio_test_locked(folio));
+
+	return __bch2_folio(folio);
+}
+
+struct bch_folio *__bch2_folio_create(struct folio *, gfp_t);
+struct bch_folio *bch2_folio_create(struct folio *, gfp_t);
+
+struct bch2_folio_reservation {
+	struct disk_reservation	disk;
+	struct quota_res	quota;
+};
+
+static inline unsigned inode_nr_replicas(struct bch_fs *c, struct bch_inode_info *inode)
+{
+	/* XXX: this should not be open coded */
+	return inode->ei_inode.bi_data_replicas
+		? inode->ei_inode.bi_data_replicas - 1
+		: c->opts.data_replicas;
+}
+
+static inline void bch2_folio_reservation_init(struct bch_fs *c,
+			struct bch_inode_info *inode,
+			struct bch2_folio_reservation *res)
+{
+	memset(res, 0, sizeof(*res));
+
+	res->disk.nr_replicas = inode_nr_replicas(c, inode);
+}
+
+int bch2_folio_set(struct bch_fs *, subvol_inum, struct folio **, unsigned);
+void bch2_bio_page_state_set(struct bio *, struct bkey_s_c);
+
+void bch2_mark_pagecache_unallocated(struct bch_inode_info *, u64, u64);
+void bch2_mark_pagecache_reserved(struct bch_inode_info *, u64, u64);
+
+int bch2_get_folio_disk_reservation(struct bch_fs *,
+				struct bch_inode_info *,
+				struct folio *, bool);
+
+void bch2_folio_reservation_put(struct bch_fs *,
+			struct bch_inode_info *,
+			struct bch2_folio_reservation *);
+int bch2_folio_reservation_get(struct bch_fs *,
+			struct bch_inode_info *,
+			struct folio *,
+			struct bch2_folio_reservation *,
+			unsigned, unsigned);
+
+void bch2_set_folio_dirty(struct bch_fs *,
+			  struct bch_inode_info *,
+			  struct folio *,
+			  struct bch2_folio_reservation *,
+			  unsigned, unsigned);
+
+vm_fault_t bch2_page_fault(struct vm_fault *);
+vm_fault_t bch2_page_mkwrite(struct vm_fault *);
+void bch2_invalidate_folio(struct folio *, size_t, size_t);
+bool bch2_release_folio(struct folio *, gfp_t);
+
+loff_t bch2_seek_pagecache_data(struct inode *, loff_t, loff_t, unsigned, bool);
+loff_t bch2_seek_pagecache_hole(struct inode *, loff_t, loff_t, unsigned, bool);
+int bch2_clamp_data_hole(struct inode *, u64 *, u64 *, unsigned, bool);
+
+#endif /* _BCACHEFS_FS_IO_PAGECACHE_H */

fs/bcachefs/fs-io.c

···
 
 #include "bcachefs.h"
 #include "alloc_foreground.h"
-#include "bkey_buf.h"
 #include "btree_update.h"
 #include "buckets.h"
 #include "clock.h"
···
 #include "extent_update.h"
 #include "fs.h"
 #include "fs-io.h"
+#include "fs-io-buffered.h"
+#include "fs-io-pagecache.h"
 #include "fsck.h"
 #include "inode.h"
 #include "journal.h"
···
 #include <linux/sched/signal.h>
 #include <linux/task_io_accounting_ops.h>
 #include <linux/uio.h>
-#include <linux/writeback.h>
 
 #include <trace/events/writeback.h>
-
-static int bch2_clamp_data_hole(struct inode *, u64 *, u64 *, unsigned, bool);
-
-struct folio_vec {
-	struct folio	*fv_folio;
-	size_t		fv_offset;
-	size_t		fv_len;
-};
-
-static inline struct folio_vec biovec_to_foliovec(struct bio_vec bv)
-{
-
-	struct folio *folio	= page_folio(bv.bv_page);
-	size_t offset		= (folio_page_idx(folio, bv.bv_page) << PAGE_SHIFT) +
-		bv.bv_offset;
-	size_t len = min_t(size_t, folio_size(folio) - offset, bv.bv_len);
-
-	return (struct folio_vec) {
-		.fv_folio	= folio,
-		.fv_offset	= offset,
-		.fv_len		= len,
-	};
-}
-
-static inline struct folio_vec bio_iter_iovec_folio(struct bio *bio,
-						    struct bvec_iter iter)
-{
-	return biovec_to_foliovec(bio_iter_iovec(bio, iter));
-}
-
-#define __bio_for_each_folio(bvl, bio, iter, start)			\
-	for (iter = (start);						\
-	     (iter).bi_size &&						\
-		((bvl = bio_iter_iovec_folio((bio), (iter))), 1);	\
-	     bio_advance_iter_single((bio), &(iter), (bvl).fv_len))
-
-/**
- * bio_for_each_folio - iterate over folios within a bio
- *
- * Like other non-_all versions, this iterates over what bio->bi_iter currently
- * points to. This version is for drivers, where the bio may have previously
- * been split or cloned.
- */
-#define bio_for_each_folio(bvl, bio, iter)				\
-	__bio_for_each_folio(bvl, bio, iter, (bio)->bi_iter)
-
-/*
- * Use u64 for the end pos and sector helpers because if the folio covers the
- * max supported range of the mapping, the start offset of the next folio
- * overflows loff_t. This breaks much of the range based processing in the
- * buffered write path.
- */
-static inline u64 folio_end_pos(struct folio *folio)
-{
-	return folio_pos(folio) + folio_size(folio);
-}
-
-static inline size_t folio_sectors(struct folio *folio)
-{
-	return PAGE_SECTORS << folio_order(folio);
-}
-
-static inline loff_t folio_sector(struct folio *folio)
-{
-	return folio_pos(folio) >> 9;
-}
-
-static inline u64 folio_end_sector(struct folio *folio)
-{
-	return folio_end_pos(folio) >> 9;
-}
-
-typedef DARRAY(struct folio *) folios;
-
-static int filemap_get_contig_folios_d(struct address_space *mapping,
-				       loff_t start, u64 end,
-				       int fgp_flags, gfp_t gfp,
-				       folios *folios)
-{
-	struct folio *f;
-	u64 pos = start;
-	int ret = 0;
-
-	while (pos < end) {
-		if ((u64) pos >= (u64) start + (1ULL << 20))
-			fgp_flags &= ~FGP_CREAT;
-
-		ret = darray_make_room_gfp(folios, 1, gfp & GFP_KERNEL);
-		if (ret)
-			break;
-
-		f = __filemap_get_folio(mapping, pos >> PAGE_SHIFT, fgp_flags, gfp);
-		if (IS_ERR_OR_NULL(f))
-			break;
-
-		BUG_ON(folios->nr && folio_pos(f) != pos);
-
-		pos = folio_end_pos(f);
-		darray_push(folios, f);
-	}
-
-	if (!folios->nr && !ret && (fgp_flags & FGP_CREAT))
-		ret = -ENOMEM;
-
-	return folios->nr ? 0 : ret;
-}
 
 struct nocow_flush {
 	struct closure	*cl;
···
 	bio_put(&bio->bio);
 }
 
-static void bch2_inode_flush_nocow_writes_async(struct bch_fs *c,
-						struct bch_inode_info *inode,
-						struct closure *cl)
+void bch2_inode_flush_nocow_writes_async(struct bch_fs *c,
+					 struct bch_inode_info *inode,
+					 struct closure *cl)
 {
 	struct nocow_flush *bio;
 	struct bch_dev *ca;
···
 	return 0;
 }
 
-static inline bool bio_full(struct bio *bio, unsigned len)
-{
-	if (bio->bi_vcnt >= bio->bi_max_vecs)
-		return true;
-	if (bio->bi_iter.bi_size > UINT_MAX - len)
-		return true;
-	return false;
-}
-
-static inline struct address_space *faults_disabled_mapping(void)
-{
-	return (void *) (((unsigned long) current->faults_disabled_mapping) & ~1UL);
-}
-
-static inline void set_fdm_dropped_locks(void)
-{
-	current->faults_disabled_mapping =
-		(void *) (((unsigned long) current->faults_disabled_mapping)|1);
-}
-
-static inline bool fdm_dropped_locks(void)
-{
-	return ((unsigned long) current->faults_disabled_mapping) & 1;
-}
-
-struct quota_res {
-	u64				sectors;
-};
-
-struct bch_writepage_io {
-	struct bch_inode_info		*inode;
-
-	/* must be last: */
-	struct bch_write_op		op;
-};
-
-struct dio_write {
-	struct kiocb			*req;
-	struct address_space		*mapping;
-	struct bch_inode_info		*inode;
-	struct mm_struct		*mm;
-	unsigned			loop:1,
-					extending:1,
-					sync:1,
-					flush:1,
-					free_iov:1;
-	struct quota_res		quota_res;
-	u64				written;
-
-	struct iov_iter			iter;
-	struct iovec			inline_vecs[2];
-
-	/* must be last: */
-	struct bch_write_op		op;
-};
-
-struct dio_read {
-	struct closure			cl;
-	struct kiocb			*req;
-	long				ret;
-	bool				should_dirty;
-	struct bch_read_bio		rbio;
-};
-
-/* pagecache_block must be held */
-static noinline int write_invalidate_inode_pages_range(struct address_space *mapping,
-					      loff_t start, loff_t end)
-{
-	int ret;
-
-	/*
-	 * XXX: the way this is currently implemented, we can spin if a process
-	 * is continually redirtying a specific page
-	 */
-	do {
-		if (!mapping->nrpages)
-			return 0;
-
-		ret = filemap_write_and_wait_range(mapping, start, end);
-		if (ret)
-			break;
-
-		if (!mapping->nrpages)
-			return 0;
-
-		ret = invalidate_inode_pages2_range(mapping,
-				start >> PAGE_SHIFT,
-				end >> PAGE_SHIFT);
-	} while (ret == -EBUSY);
-
-	return ret;
-}
-
-/* quotas */
-
-#ifdef CONFIG_BCACHEFS_QUOTA
-
-static void __bch2_quota_reservation_put(struct bch_fs *c,
-					 struct bch_inode_info *inode,
-					 struct quota_res *res)
-{
-	BUG_ON(res->sectors > inode->ei_quota_reserved);
-
-	bch2_quota_acct(c, inode->ei_qid, Q_SPC,
-			-((s64) res->sectors), KEY_TYPE_QUOTA_PREALLOC);
-	inode->ei_quota_reserved -= res->sectors;
-	res->sectors = 0;
-}
-
-static void bch2_quota_reservation_put(struct bch_fs *c,
-				       struct bch_inode_info *inode,
-				       struct quota_res *res)
-{
-	if (res->sectors) {
-		mutex_lock(&inode->ei_quota_lock);
-		__bch2_quota_reservation_put(c, inode, res);
-		mutex_unlock(&inode->ei_quota_lock);
-	}
-}
-
-static int bch2_quota_reservation_add(struct bch_fs *c,
-				      struct bch_inode_info *inode,
-				      struct quota_res *res,
-				      u64 sectors,
-				      bool check_enospc)
-{
-	int ret;
-
-	if (test_bit(EI_INODE_SNAPSHOT, &inode->ei_flags))
-		return 0;
-
-	mutex_lock(&inode->ei_quota_lock);
-	ret = bch2_quota_acct(c, inode->ei_qid, Q_SPC, sectors,
-			      check_enospc ? KEY_TYPE_QUOTA_PREALLOC : KEY_TYPE_QUOTA_NOCHECK);
-	if (likely(!ret)) {
-		inode->ei_quota_reserved += sectors;
-		res->sectors += sectors;
-	}
-	mutex_unlock(&inode->ei_quota_lock);
-
-	return ret;
-}
-
-#else
-
-static void __bch2_quota_reservation_put(struct bch_fs *c,
-					 struct bch_inode_info *inode,
-					 struct quota_res *res) {}
-
-static void bch2_quota_reservation_put(struct bch_fs *c,
-				       struct bch_inode_info *inode,
-				       struct quota_res *res) {}
-
-static int bch2_quota_reservation_add(struct bch_fs *c,
-				      struct bch_inode_info *inode,
-				      struct quota_res *res,
-				      unsigned sectors,
-				      bool check_enospc)
-{
-	return 0;
-}
-
-#endif
-
 /* i_size updates: */
 
 struct inode_new_size {
···
 	return bch2_write_inode(c, inode, inode_set_size, &s, fields);
 }
 
-static void __i_sectors_acct(struct bch_fs *c, struct bch_inode_info *inode,
+void __bch2_i_sectors_acct(struct bch_fs *c, struct bch_inode_info *inode,
 			   struct quota_res *quota_res, s64 sectors)
 {
 	bch2_fs_inconsistent_on((s64) inode->v.i_blocks + sectors < 0, c,
···
 		bch2_quota_acct(c, inode->ei_qid, Q_SPC, sectors, KEY_TYPE_QUOTA_WARN);
 	}
 #endif
-}
-
-static void i_sectors_acct(struct bch_fs *c, struct bch_inode_info *inode,
-			   struct quota_res *quota_res, s64 sectors)
-{
-	if (sectors) {
-		mutex_lock(&inode->ei_quota_lock);
-		__i_sectors_acct(c, inode, quota_res, sectors);
-		mutex_unlock(&inode->ei_quota_lock);
-	}
-}
-
-/* page state: */
-
-/* stored in page->private: */
-
-#define BCH_FOLIO_SECTOR_STATE()	\
-	x(unallocated)			\
-	x(reserved)			\
-	x(dirty)			\
-	x(dirty_reserved)		\
-	x(allocated)
-
-enum bch_folio_sector_state {
-#define x(n)	SECTOR_##n,
-	BCH_FOLIO_SECTOR_STATE()
-#undef x
-};
-
-static const char * const bch2_folio_sector_states[] = {
-#define x(n)	#n,
-	BCH_FOLIO_SECTOR_STATE()
-#undef x
-	NULL
-};
-
-static inline enum bch_folio_sector_state
-folio_sector_dirty(enum bch_folio_sector_state state)
-{
-	switch (state) {
-	case SECTOR_unallocated:
-		return SECTOR_dirty;
-	case SECTOR_reserved:
-		return SECTOR_dirty_reserved;
-	default:
-		return state;
-	}
-}
-
-static inline enum bch_folio_sector_state
-folio_sector_undirty(enum bch_folio_sector_state state)
-{
-	switch (state) {
-	case SECTOR_dirty:
-		return SECTOR_unallocated;
-	case SECTOR_dirty_reserved:
-		return SECTOR_reserved;
-	default:
-		return state;
-	}
-}
-
-static inline enum bch_folio_sector_state
-folio_sector_reserve(enum bch_folio_sector_state state)
-{
-	switch (state) {
-	case SECTOR_unallocated:
-		return SECTOR_reserved;
-	case SECTOR_dirty:
-		return SECTOR_dirty_reserved;
-	default:
-		return state;
-	}
-}
-
-struct bch_folio_sector {
-	/* Uncompressed, fully allocated replicas (or on disk reservation): */
-	unsigned		nr_replicas:4;
-
-	/* Owns PAGE_SECTORS * replicas_reserved sized in memory reservation: */
-	unsigned		replicas_reserved:4;
-
-	/* i_sectors: */
-	enum bch_folio_sector_state state:8;
-};
-
-struct bch_folio {
-	spinlock_t		lock;
-	atomic_t		write_count;
-	/*
-	 * Is the sector state up to date with the btree?
-	 * (Not the data itself)
-	 */
-	bool			uptodate;
-	struct bch_folio_sector	s[];
-};
-
-static inline void folio_sector_set(struct folio *folio,
-			     struct bch_folio *s,
-			     unsigned i, unsigned n)
-{
-	s->s[i].state = n;
-}
-
-/* file offset (to folio offset) to bch_folio_sector index */
-static inline int folio_pos_to_s(struct folio *folio, loff_t pos)
-{
-	u64 f_offset = pos - folio_pos(folio);
-	BUG_ON(pos < folio_pos(folio) || pos >= folio_end_pos(folio));
-	return f_offset >> SECTOR_SHIFT;
-}
-
-static inline struct bch_folio *__bch2_folio(struct folio *folio)
-{
-	return folio_has_private(folio)
-		? (struct bch_folio *) folio_get_private(folio)
-		: NULL;
-}
-
-static inline struct bch_folio *bch2_folio(struct folio *folio)
-{
-	EBUG_ON(!folio_test_locked(folio));
-
-	return __bch2_folio(folio);
-}
-
-/* for newly allocated folios: */
-static void __bch2_folio_release(struct folio *folio)
-{
-	kfree(folio_detach_private(folio));
-}
-
-static void bch2_folio_release(struct folio *folio)
-{
-	EBUG_ON(!folio_test_locked(folio));
-	__bch2_folio_release(folio);
-}
-
-/* for newly allocated folios: */
-static struct bch_folio *__bch2_folio_create(struct folio *folio, gfp_t gfp)
-{
-	struct bch_folio *s;
-
-	s = kzalloc(sizeof(*s) +
-		    sizeof(struct bch_folio_sector) *
-		    folio_sectors(folio), gfp);
-	if (!s)
-		return NULL;
-
-	spin_lock_init(&s->lock);
-	folio_attach_private(folio, s);
-	return s;
-}
-
-static struct bch_folio *bch2_folio_create(struct folio *folio, gfp_t gfp)
-{
-	return bch2_folio(folio) ?: __bch2_folio_create(folio, gfp);
-}
-
-static unsigned bkey_to_sector_state(struct bkey_s_c k)
-{
-	if (bkey_extent_is_reservation(k))
-		return SECTOR_reserved;
-	if (bkey_extent_is_allocation(k.k))
-		return SECTOR_allocated;
-	return SECTOR_unallocated;
-}
-
-static void __bch2_folio_set(struct folio *folio,
-			     unsigned pg_offset, unsigned pg_len,
-			     unsigned nr_ptrs, unsigned state)
-{
-	struct bch_folio *s = bch2_folio(folio);
-	unsigned i, sectors = folio_sectors(folio);
-
-	BUG_ON(pg_offset >= sectors);
-	BUG_ON(pg_offset + pg_len > sectors);
-
-	spin_lock(&s->lock);
-
-	for (i = pg_offset; i < pg_offset + pg_len; i++) {
-		s->s[i].nr_replicas	= nr_ptrs;
-		folio_sector_set(folio, s, i, state);
-	}
-
-	if (i == sectors)
-		s->uptodate = true;
-
-	spin_unlock(&s->lock);
-}
-
-/*
- * Initialize bch_folio state (allocated/unallocated, nr_replicas) from the
- * extents btree:
- */
-static int bch2_folio_set(struct bch_fs *c, subvol_inum inum,
-			  struct folio **folios, unsigned nr_folios)
-{
-	struct btree_trans trans;
-	struct btree_iter iter;
-	struct bkey_s_c k;
-	struct bch_folio *s;
-	u64 offset = folio_sector(folios[0]);
-	unsigned folio_idx;
-	u32 snapshot;
-	bool need_set = false;
-	int ret;
-
-	for (folio_idx = 0; folio_idx < nr_folios; folio_idx++) {
-		s = bch2_folio_create(folios[folio_idx], GFP_KERNEL);
-		if (!s)
-			return -ENOMEM;
-
-		need_set |= !s->uptodate;
-	}
-
-	if (!need_set)
-		return 0;
-
-	folio_idx = 0;
-	bch2_trans_init(&trans, c, 0, 0);
-retry:
-	bch2_trans_begin(&trans);
-
-	ret = bch2_subvolume_get_snapshot(&trans, inum.subvol, &snapshot);
-	if (ret)
-		goto err;
-
-	for_each_btree_key_norestart(&trans, iter, BTREE_ID_extents,
-			   SPOS(inum.inum, offset, snapshot),
-			   BTREE_ITER_SLOTS, k, ret) {
-		unsigned nr_ptrs = bch2_bkey_nr_ptrs_fully_allocated(k);
-		unsigned state = bkey_to_sector_state(k);
-
-		while (folio_idx < nr_folios) {
-			struct folio *folio = folios[folio_idx];
-			u64 folio_start	= folio_sector(folio);
-			u64 folio_end	= folio_end_sector(folio);
-			unsigned folio_offset = max(bkey_start_offset(k.k), folio_start) - folio_start;
-			unsigned folio_len = min(k.k->p.offset, folio_end) - folio_offset - folio_start;
-
-			BUG_ON(k.k->p.offset < folio_start);
-			BUG_ON(bkey_start_offset(k.k) > folio_end);
-
-			if (!bch2_folio(folio)->uptodate)
-				__bch2_folio_set(folio, folio_offset, folio_len, nr_ptrs, state);
-
-			if (k.k->p.offset < folio_end)
-				break;
-			folio_idx++;
-		}
-
-		if (folio_idx == nr_folios)
-			break;
-	}
-
-	offset = iter.pos.offset;
-	bch2_trans_iter_exit(&trans, &iter);
-err:
-	if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
-		goto retry;
-	bch2_trans_exit(&trans);
-
-	return ret;
-}
-
-static void bch2_bio_page_state_set(struct bio *bio, struct bkey_s_c k)
-{
-	struct bvec_iter iter;
-	struct folio_vec fv;
-	unsigned nr_ptrs = k.k->type == KEY_TYPE_reflink_v
-		? 0 : bch2_bkey_nr_ptrs_fully_allocated(k);
-	unsigned state = bkey_to_sector_state(k);
-
-	bio_for_each_folio(fv, bio, iter)
-		__bch2_folio_set(fv.fv_folio,
-				 fv.fv_offset >> 9,
-				 fv.fv_len >> 9,
-				 nr_ptrs, state);
-}
-
-static void mark_pagecache_unallocated(struct bch_inode_info *inode,
-				       u64 start, u64 end)
-{
-	pgoff_t index = start >> PAGE_SECTORS_SHIFT;
-	pgoff_t end_index = (end - 1) >> PAGE_SECTORS_SHIFT;
-	struct folio_batch fbatch;
-	unsigned i, j;
-
-	if (end <= start)
-		return;
-
-	folio_batch_init(&fbatch);
-
-	while (filemap_get_folios(inode->v.i_mapping,
-				  &index, end_index, &fbatch)) {
-		for (i = 0; i < folio_batch_count(&fbatch); i++) {
-			struct folio *folio = fbatch.folios[i];
-			u64 folio_start = folio_sector(folio);
-			u64 folio_end = folio_end_sector(folio);
-			unsigned folio_offset = max(start, folio_start) - folio_start;
-			unsigned folio_len = min(end, folio_end) - folio_offset - folio_start;
-			struct bch_folio *s;
-
-			BUG_ON(end <= folio_start);
-
-			folio_lock(folio);
-			s = bch2_folio(folio);
-
-			if (s) {
-				spin_lock(&s->lock);
-				for (j = folio_offset; j < folio_offset + folio_len; j++)
-					s->s[j].nr_replicas = 0;
-				spin_unlock(&s->lock);
-			}
-
-			folio_unlock(folio);
-		}
-		folio_batch_release(&fbatch);
-		cond_resched();
-	}
-}
-
-static void mark_pagecache_reserved(struct bch_inode_info *inode,
-				    u64 start, u64 end)
-{
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	pgoff_t index = start >> PAGE_SECTORS_SHIFT;
-	pgoff_t end_index = (end - 1) >> PAGE_SECTORS_SHIFT;
-	struct folio_batch fbatch;
-	s64 i_sectors_delta = 0;
-	unsigned i, j;
-
-	if (end <= start)
-		return;
-
-	folio_batch_init(&fbatch);
-
-	while (filemap_get_folios(inode->v.i_mapping,
-				  &index, end_index, &fbatch)) {
-		for (i = 0; i < folio_batch_count(&fbatch); i++) {
-			struct folio *folio = fbatch.folios[i];
-			u64 folio_start = folio_sector(folio);
-			u64 folio_end = folio_end_sector(folio);
-			unsigned folio_offset = max(start, folio_start) - folio_start;
-			unsigned folio_len = min(end, folio_end) - folio_offset - folio_start;
-			struct bch_folio *s;
-
-			BUG_ON(end <= folio_start);
-
-			folio_lock(folio);
-			s = bch2_folio(folio);
-
-			if (s) {
-				spin_lock(&s->lock);
-				for (j = folio_offset; j < folio_offset + folio_len; j++) {
-					i_sectors_delta -= s->s[j].state == SECTOR_dirty;
-					folio_sector_set(folio, s, j, folio_sector_reserve(s->s[j].state));
-				}
-				spin_unlock(&s->lock);
-			}
-
-			folio_unlock(folio);
-		}
-		folio_batch_release(&fbatch);
-		cond_resched();
-	}
-
-	i_sectors_acct(c, inode, NULL, i_sectors_delta);
-}
-
-static inline unsigned inode_nr_replicas(struct bch_fs *c, struct bch_inode_info *inode)
-{
-	/* XXX: this should not be open coded */
-	return inode->ei_inode.bi_data_replicas
-		? inode->ei_inode.bi_data_replicas - 1
-		: c->opts.data_replicas;
-}
-
-static inline unsigned sectors_to_reserve(struct bch_folio_sector *s,
-					  unsigned nr_replicas)
-{
-	return max(0, (int) nr_replicas -
-		   s->nr_replicas -
-		   s->replicas_reserved);
-}
-
-static int bch2_get_folio_disk_reservation(struct bch_fs *c,
-				struct bch_inode_info *inode,
-				struct folio *folio, bool check_enospc)
-{
-	struct bch_folio *s = bch2_folio_create(folio, 0);
-	unsigned nr_replicas = inode_nr_replicas(c, inode);
-	struct disk_reservation disk_res = { 0 };
-	unsigned i, sectors = folio_sectors(folio), disk_res_sectors = 0;
-	int ret;
-
-	if (!s)
-		return -ENOMEM;
-
-	for (i = 0; i < sectors; i++)
-		disk_res_sectors += sectors_to_reserve(&s->s[i], nr_replicas);
-
-	if (!disk_res_sectors)
-		return 0;
-
-	ret = bch2_disk_reservation_get(c, &disk_res,
-					disk_res_sectors, 1,
-					!check_enospc
-					? BCH_DISK_RESERVATION_NOFAIL
-					: 0);
-	if (unlikely(ret))
-		return ret;
-
-	for (i = 0; i < sectors; i++)
-		s->s[i].replicas_reserved +=
-			sectors_to_reserve(&s->s[i], nr_replicas);
-
-	return 0;
-}
-
-struct bch2_folio_reservation {
-	struct disk_reservation	disk;
-	struct quota_res	quota;
-};
-
-static void bch2_folio_reservation_init(struct bch_fs *c,
-			struct bch_inode_info *inode,
-			struct bch2_folio_reservation *res)
-{
-	memset(res, 0, sizeof(*res));
-
-	res->disk.nr_replicas = inode_nr_replicas(c, inode);
-}
-
-static void bch2_folio_reservation_put(struct bch_fs *c,
-			struct bch_inode_info *inode,
-			struct bch2_folio_reservation *res)
-{
-	bch2_disk_reservation_put(c, &res->disk);
-	bch2_quota_reservation_put(c, inode, &res->quota);
-}
-
-static int bch2_folio_reservation_get(struct bch_fs *c,
-			struct bch_inode_info *inode,
-			struct folio *folio,
-			struct bch2_folio_reservation *res,
-			unsigned offset, unsigned len)
-{
-	struct bch_folio *s = bch2_folio_create(folio, 0);
-	unsigned i, disk_sectors = 0, quota_sectors = 0;
-	int ret;
-
-	if (!s)
-		return -ENOMEM;
-
-	BUG_ON(!s->uptodate);
-
-	for (i = round_down(offset, block_bytes(c)) >> 9;
-	     i < round_up(offset + len, block_bytes(c)) >> 9;
-	     i++) {
-		disk_sectors += sectors_to_reserve(&s->s[i],
-						res->disk.nr_replicas);
-		quota_sectors += s->s[i].state == SECTOR_unallocated;
-	}
-
-	if (disk_sectors) {
-		ret = bch2_disk_reservation_add(c, &res->disk, disk_sectors, 0);
-		if (unlikely(ret))
-			return ret;
-	}
-
-	if (quota_sectors) {
-		ret = bch2_quota_reservation_add(c, inode, &res->quota,
-						 quota_sectors, true);
-		if (unlikely(ret)) {
-			struct disk_reservation tmp = {
-				.sectors = disk_sectors
-			};
-
-			bch2_disk_reservation_put(c, &tmp);
-			res->disk.sectors -= disk_sectors;
-			return ret;
-		}
-	}
-
-	return 0;
-}
-
-static void bch2_clear_folio_bits(struct folio *folio)
-{
-	struct bch_inode_info *inode = to_bch_ei(folio->mapping->host);
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	struct bch_folio *s = bch2_folio(folio);
-	struct disk_reservation disk_res = { 0 };
-	int i, sectors = folio_sectors(folio), dirty_sectors = 0;
-
-	if (!s)
-		return;
-
-	EBUG_ON(!folio_test_locked(folio));
-	EBUG_ON(folio_test_writeback(folio));
-
-	for (i = 0; i < sectors; i++) {
-		disk_res.sectors += s->s[i].replicas_reserved;
-		s->s[i].replicas_reserved = 0;
-
-		dirty_sectors -= s->s[i].state == SECTOR_dirty;
-		folio_sector_set(folio, s, i, folio_sector_undirty(s->s[i].state));
-	}
-
-	bch2_disk_reservation_put(c, &disk_res);
-
-	i_sectors_acct(c, inode, NULL, dirty_sectors);
-
-	bch2_folio_release(folio);
-}
-
-static void bch2_set_folio_dirty(struct bch_fs *c,
-			struct bch_inode_info *inode,
-			struct folio *folio,
-			struct bch2_folio_reservation *res,
-			unsigned offset, unsigned len)
-{
-	struct bch_folio *s = bch2_folio(folio);
-	unsigned i, dirty_sectors = 0;
-
-	WARN_ON((u64) folio_pos(folio) + offset + len >
-		round_up((u64) i_size_read(&inode->v), block_bytes(c)));
-
-	BUG_ON(!s->uptodate);
-
-	spin_lock(&s->lock);
-
-	for (i = round_down(offset, block_bytes(c)) >> 9;
-	     i < round_up(offset + len, block_bytes(c)) >> 9;
-	     i++) {
-		unsigned sectors = sectors_to_reserve(&s->s[i],
-						res->disk.nr_replicas);
-
-		/*
-		 * This can happen if we race with the error path in
-		 * bch2_writepage_io_done():
-		 */
-		sectors = min_t(unsigned, sectors, res->disk.sectors);
-
-		s->s[i].replicas_reserved += sectors;
-		res->disk.sectors -= sectors;
-
-		dirty_sectors += s->s[i].state == SECTOR_unallocated;
-
-		folio_sector_set(folio, s, i, folio_sector_dirty(s->s[i].state));
-	}
-
-	spin_unlock(&s->lock);
-
-	i_sectors_acct(c, inode, &res->quota, dirty_sectors);
-
-	if (!folio_test_dirty(folio))
-		filemap_dirty_folio(inode->v.i_mapping, folio);
-}
-
-vm_fault_t bch2_page_fault(struct vm_fault *vmf)
-{
-	struct file *file = vmf->vma->vm_file;
-	struct address_space *mapping = file->f_mapping;
-	struct address_space *fdm = faults_disabled_mapping();
-	struct bch_inode_info *inode = file_bch_inode(file);
-	vm_fault_t ret;
-
-	if (fdm == mapping)
-		return VM_FAULT_SIGBUS;
-
-	/* Lock ordering: */
-	if (fdm > mapping) {
-		struct bch_inode_info *fdm_host = to_bch_ei(fdm->host);
-
-		if (bch2_pagecache_add_tryget(inode))
-			goto got_lock;
-
-		bch2_pagecache_block_put(fdm_host);
-
-		bch2_pagecache_add_get(inode);
-		bch2_pagecache_add_put(inode);
-
-		bch2_pagecache_block_get(fdm_host);
-
-		/* Signal that lock has been dropped: */
-		set_fdm_dropped_locks();
-		return VM_FAULT_SIGBUS;
-	}
-
-	bch2_pagecache_add_get(inode);
-got_lock:
-	ret = filemap_fault(vmf);
-	bch2_pagecache_add_put(inode);
-
-	return ret;
-}
-
-vm_fault_t bch2_page_mkwrite(struct vm_fault *vmf)
-{
-	struct folio *folio = page_folio(vmf->page);
-	struct file *file = vmf->vma->vm_file;
-	struct bch_inode_info *inode = file_bch_inode(file);
-	struct address_space *mapping = file->f_mapping;
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	struct bch2_folio_reservation res;
-	unsigned len;
-	loff_t isize;
-	vm_fault_t ret;
-
-	bch2_folio_reservation_init(c, inode, &res);
-
-	sb_start_pagefault(inode->v.i_sb);
-	file_update_time(file);
-
-	/*
-	 * Not strictly necessary, but helps avoid dio writes livelocking in
-	 * write_invalidate_inode_pages_range() - can drop this if/when we get
-	 * a write_invalidate_inode_pages_range() that works without dropping
-	 * page lock before invalidating page
-	 */
-	bch2_pagecache_add_get(inode);
-
-	folio_lock(folio);
-	isize = i_size_read(&inode->v);
-
-	if (folio->mapping != mapping || folio_pos(folio) >= isize) {
-		folio_unlock(folio);
-		ret = VM_FAULT_NOPAGE;
-		goto out;
-	}
-
-	len = min_t(loff_t, folio_size(folio), isize - folio_pos(folio));
-
-	if (bch2_folio_set(c, inode_inum(inode), &folio, 1) ?:
-	    bch2_folio_reservation_get(c, inode, folio, &res, 0, len)) {
-		folio_unlock(folio);
-		ret = VM_FAULT_SIGBUS;
-		goto out;
-	}
-
-	bch2_set_folio_dirty(c, inode, folio, &res, 0, len);
-	bch2_folio_reservation_put(c, inode, &res);
-
-	folio_wait_stable(folio);
-	ret = VM_FAULT_LOCKED;
-out:
-	bch2_pagecache_add_put(inode);
-	sb_end_pagefault(inode->v.i_sb);
-
-	return ret;
-}
-
-void bch2_invalidate_folio(struct folio *folio, size_t offset, size_t length)
-{
-	if (offset || length < folio_size(folio))
-		return;
-
-	bch2_clear_folio_bits(folio);
-}
-
-bool bch2_release_folio(struct folio *folio, gfp_t gfp_mask)
-{
-	if (folio_test_dirty(folio) || folio_test_writeback(folio))
-		return false;
-
-	bch2_clear_folio_bits(folio);
-	return true;
-}
-
-/* readpage(s): */
-
-static void bch2_readpages_end_io(struct bio *bio)
-{
-	struct folio_iter fi;
-
-	bio_for_each_folio_all(fi, bio) {
-		if (!bio->bi_status) {
-			folio_mark_uptodate(fi.folio);
-		} else {
-			folio_clear_uptodate(fi.folio);
-			folio_set_error(fi.folio);
-		}
-		folio_unlock(fi.folio);
-	}
-
-	bio_put(bio);
-}
-
-struct readpages_iter {
-	struct address_space	*mapping;
-	unsigned		idx;
-	folios			folios;
-};
-
-static int readpages_iter_init(struct readpages_iter *iter,
-			       struct readahead_control *ractl)
-{
-	struct folio **fi;
-	int ret;
-
-	memset(iter, 0, sizeof(*iter));
-
-	iter->mapping = ractl->mapping;
-
-	ret = filemap_get_contig_folios_d(iter->mapping,
-				ractl->_index << PAGE_SHIFT,
-				(ractl->_index + ractl->_nr_pages) << PAGE_SHIFT,
-				0, mapping_gfp_mask(iter->mapping),
-				&iter->folios);
-	if (ret)
-		return ret;
-
-	darray_for_each(iter->folios, fi) {
-		ractl->_nr_pages -= 1U << folio_order(*fi);
-		__bch2_folio_create(*fi, __GFP_NOFAIL|GFP_KERNEL);
-		folio_put(*fi);
-		folio_put(*fi);
-	}
-
-	return 0;
-}
-
-static inline struct folio *readpage_iter_peek(struct readpages_iter *iter)
-{
-	if (iter->idx >= iter->folios.nr)
-		return NULL;
-	return iter->folios.data[iter->idx];
-}
-
-static inline void readpage_iter_advance(struct readpages_iter *iter)
-{
-	iter->idx++;
-}
-
-static bool extent_partial_reads_expensive(struct bkey_s_c k)
-{
-	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
-	struct bch_extent_crc_unpacked crc;
-	const union bch_extent_entry *i;
-
-	bkey_for_each_crc(k.k, ptrs, crc, i)
-		if (crc.csum_type || crc.compression_type)
-			return true;
-	return false;
-}
-
-static int readpage_bio_extend(struct btree_trans *trans,
-			       struct readpages_iter *iter,
-			       struct bio *bio,
-			       unsigned sectors_this_extent,
-			       bool get_more)
-{
-	/* Don't hold btree locks while allocating memory: */
-	bch2_trans_unlock(trans);
-
-	while (bio_sectors(bio) < sectors_this_extent &&
-	       bio->bi_vcnt < bio->bi_max_vecs) {
-		struct folio *folio = readpage_iter_peek(iter);
-		int ret;
-
-		if (folio) {
-			readpage_iter_advance(iter);
-		} else {
-			pgoff_t folio_offset = bio_end_sector(bio) >> PAGE_SECTORS_SHIFT;
-
-			if (!get_more)
-				break;
-
-			folio = xa_load(&iter->mapping->i_pages, folio_offset);
-			if (folio && !xa_is_value(folio))
-				break;
-
-			folio = filemap_alloc_folio(readahead_gfp_mask(iter->mapping), 0);
-			if (!folio)
-				break;
-
-			if (!__bch2_folio_create(folio, GFP_KERNEL)) {
-				folio_put(folio);
-				break;
-			}
-
-			ret = filemap_add_folio(iter->mapping, folio, folio_offset, GFP_KERNEL);
-			if (ret) {
-				__bch2_folio_release(folio);
-				folio_put(folio);
-				break;
-			}
-
-			folio_put(folio);
-		}
-
-		BUG_ON(folio_sector(folio) != bio_end_sector(bio));
-
-		BUG_ON(!bio_add_folio(bio, folio, folio_size(folio), 0));
-	}
-
-	return bch2_trans_relock(trans);
-}
-
-static void bchfs_read(struct btree_trans *trans,
-		       struct bch_read_bio *rbio,
-		       subvol_inum inum,
-		       struct readpages_iter *readpages_iter)
-{
-	struct bch_fs *c = trans->c;
-	struct btree_iter iter;
-	struct bkey_buf sk;
-	int flags = BCH_READ_RETRY_IF_STALE|
-		BCH_READ_MAY_PROMOTE;
-	u32 snapshot;
-	int ret = 0;
-
-	rbio->c = c;
-	rbio->start_time = local_clock();
-	rbio->subvol = inum.subvol;
-
-	bch2_bkey_buf_init(&sk);
-retry:
-	bch2_trans_begin(trans);
-	iter = (struct btree_iter) { NULL };
-
-	ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
-	if (ret)
-		goto err;
-
-	bch2_trans_iter_init(trans, &iter, BTREE_ID_extents,
-			     SPOS(inum.inum, rbio->bio.bi_iter.bi_sector, snapshot),
-			     BTREE_ITER_SLOTS);
-	while (1) {
-		struct bkey_s_c k;
-		unsigned bytes, sectors, offset_into_extent;
-		enum btree_id data_btree = BTREE_ID_extents;
-
-		/*
-		 * read_extent -> io_time_reset may cause a transaction restart
-		 * without returning an error, we need to check for that here:
-		 */
-		ret = bch2_trans_relock(trans);
-		if (ret)
-			break;
-
-		bch2_btree_iter_set_pos(&iter,
-				POS(inum.inum, rbio->bio.bi_iter.bi_sector));
-
-		k = bch2_btree_iter_peek_slot(&iter);
-		ret = bkey_err(k);
-		if (ret)
-			break;
-
-		offset_into_extent = iter.pos.offset -
-			bkey_start_offset(k.k);
-		sectors = k.k->size - offset_into_extent;
-
-		bch2_bkey_buf_reassemble(&sk, c, k);
-
-		ret = bch2_read_indirect_extent(trans, &data_btree,
-					&offset_into_extent, &sk);
-		if (ret)
-			break;
-
-		k = bkey_i_to_s_c(sk.k);
-
-		sectors = min(sectors, k.k->size - offset_into_extent);
-
-		if (readpages_iter) {
-			ret = readpage_bio_extend(trans, readpages_iter, &rbio->bio, sectors,
-						  extent_partial_reads_expensive(k));
-			if (ret)
-				break;
-		}
-
-		bytes = min(sectors, bio_sectors(&rbio->bio)) << 9;
-		swap(rbio->bio.bi_iter.bi_size, bytes);
-
-		if (rbio->bio.bi_iter.bi_size == bytes)
-			flags |= BCH_READ_LAST_FRAGMENT;
-
-		bch2_bio_page_state_set(&rbio->bio, k);
-
-		bch2_read_extent(trans, rbio, iter.pos,
-				 data_btree, k, offset_into_extent, flags);
-
-		if (flags & BCH_READ_LAST_FRAGMENT)
-			break;
-
-		swap(rbio->bio.bi_iter.bi_size, bytes);
-		bio_advance(&rbio->bio, bytes);
-
-		ret = btree_trans_too_many_iters(trans);
-		if (ret)
-			break;
-	}
-err:
-	bch2_trans_iter_exit(trans, &iter);
-
-	if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
-		goto retry;
-
-	if (ret) {
-		bch_err_inum_offset_ratelimited(c,
-				iter.pos.inode,
-				iter.pos.offset << 9,
-				"read error %i from btree lookup", ret);
-		rbio->bio.bi_status = BLK_STS_IOERR;
-		bio_endio(&rbio->bio);
-	}
-
-	bch2_bkey_buf_exit(&sk, c);
-}
-
-void bch2_readahead(struct readahead_control *ractl)
-{
-	struct bch_inode_info *inode = to_bch_ei(ractl->mapping->host);
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	struct bch_io_opts opts;
-	struct btree_trans trans;
-	struct folio *folio;
-	struct readpages_iter readpages_iter;
-	int ret;
-
-	bch2_inode_opts_get(&opts, c, &inode->ei_inode);
-
-	ret = readpages_iter_init(&readpages_iter, ractl);
-	BUG_ON(ret);
-
-	bch2_trans_init(&trans, c, 0, 0);
-
-	bch2_pagecache_add_get(inode);
-
-	while ((folio = readpage_iter_peek(&readpages_iter))) {
-		unsigned n = min_t(unsigned,
-				   readpages_iter.folios.nr -
-				   readpages_iter.idx,
-				   BIO_MAX_VECS);
-		struct bch_read_bio *rbio =
-			rbio_init(bio_alloc_bioset(NULL, n, REQ_OP_READ,
-						   GFP_KERNEL, &c->bio_read),
-				  opts);
-
-		readpage_iter_advance(&readpages_iter);
-
-		rbio->bio.bi_iter.bi_sector = folio_sector(folio);
-		rbio->bio.bi_end_io = bch2_readpages_end_io;
-		BUG_ON(!bio_add_folio(&rbio->bio, folio, folio_size(folio), 0));
-
-		bchfs_read(&trans, rbio, inode_inum(inode),
-			   &readpages_iter);
-		bch2_trans_unlock(&trans);
-	}
-
-	bch2_pagecache_add_put(inode);
-
-	bch2_trans_exit(&trans);
-	darray_exit(&readpages_iter.folios);
-}
-
-static void __bchfs_readfolio(struct bch_fs *c, struct bch_read_bio *rbio,
-			     subvol_inum inum, struct folio *folio)
-{
-	struct btree_trans trans;
-
-	bch2_folio_create(folio, __GFP_NOFAIL);
-
-	rbio->bio.bi_opf = REQ_OP_READ|REQ_SYNC;
-	rbio->bio.bi_iter.bi_sector = folio_sector(folio);
-	BUG_ON(!bio_add_folio(&rbio->bio, folio, folio_size(folio), 0));
-
-	bch2_trans_init(&trans, c, 0, 0);
-	bchfs_read(&trans, rbio, inum, NULL);
-	bch2_trans_exit(&trans);
-}
-
-static void bch2_read_single_folio_end_io(struct bio *bio)
-{
-	complete(bio->bi_private);
-}
-
-static int bch2_read_single_folio(struct folio *folio,
-				  struct address_space *mapping)
-{
-	struct bch_inode_info *inode = to_bch_ei(mapping->host);
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	struct bch_read_bio *rbio;
-	struct bch_io_opts opts;
-	int ret;
-	DECLARE_COMPLETION_ONSTACK(done);
-
-	bch2_inode_opts_get(&opts, c, &inode->ei_inode);
-
-	rbio = rbio_init(bio_alloc_bioset(NULL, 1, REQ_OP_READ, GFP_KERNEL, &c->bio_read),
-			 opts);
-	rbio->bio.bi_private = &done;
-	rbio->bio.bi_end_io = bch2_read_single_folio_end_io;
-
-	__bchfs_readfolio(c, rbio, inode_inum(inode), folio);
-	wait_for_completion(&done);
-
-	ret = blk_status_to_errno(rbio->bio.bi_status);
-	bio_put(&rbio->bio);
-
-	if (ret < 0)
-		return ret;
-
-	folio_mark_uptodate(folio);
-	return 0;
-}
-
-int bch2_read_folio(struct file *file, struct folio *folio)
-{
-	int ret;
-
-	ret = bch2_read_single_folio(folio, folio->mapping);
-	folio_unlock(folio);
-	return bch2_err_class(ret);
-}
-
-/* writepages: */
-
-struct bch_writepage_state {
-	struct bch_writepage_io	*io;
-	struct bch_io_opts	opts;
-	struct bch_folio_sector	*tmp;
-	unsigned		tmp_sectors;
-};
-
-static inline struct bch_writepage_state bch_writepage_state_init(struct bch_fs *c,
-								  struct bch_inode_info *inode)
-{
-	struct bch_writepage_state ret = { 0 };
-
-	bch2_inode_opts_get(&ret.opts, c, &inode->ei_inode);
-	return ret;
-}
-
-static void bch2_writepage_io_done(struct bch_write_op *op)
-{
-	struct bch_writepage_io *io =
-		container_of(op, struct bch_writepage_io, op);
-	struct bch_fs *c = io->op.c;
-	struct bio *bio = &io->op.wbio.bio;
-	struct folio_iter fi;
-	unsigned i;
-
-	if (io->op.error) {
-		set_bit(EI_INODE_ERROR, &io->inode->ei_flags);
-
-		bio_for_each_folio_all(fi, bio) {
-			struct bch_folio *s;
-
-			folio_set_error(fi.folio);
-			mapping_set_error(fi.folio->mapping, -EIO);
-
-			s = __bch2_folio(fi.folio);
-			spin_lock(&s->lock);
-			for (i = 0; i < folio_sectors(fi.folio); i++)
-				s->s[i].nr_replicas = 0;
-			spin_unlock(&s->lock);
-		}
-	}
-
-	if (io->op.flags & BCH_WRITE_WROTE_DATA_INLINE) {
-		bio_for_each_folio_all(fi, bio) {
-			struct bch_folio *s;
-
-			s = __bch2_folio(fi.folio);
-			spin_lock(&s->lock);
-			for (i = 0; i < folio_sectors(fi.folio); i++)
-				s->s[i].nr_replicas = 0;
-			spin_unlock(&s->lock);
-		}
-	}
-
-	/*
-	 * racing with fallocate can cause us to add fewer sectors than
-	 * expected - but we shouldn't add more sectors than expected:
-	 */
-	WARN_ON_ONCE(io->op.i_sectors_delta > 0);
-
-	/*
-	 * (error (due to going RO) halfway through a page can screw that up
-	 * slightly)
-	 * XXX wtf?
-	   BUG_ON(io->op.op.i_sectors_delta >= PAGE_SECTORS);
-	 */
-
-	/*
-	 * PageWriteback is effectively our ref on the inode - fixup i_blocks
-	 * before calling end_page_writeback:
-	 */
-	i_sectors_acct(c, io->inode, NULL, io->op.i_sectors_delta);
-
-	bio_for_each_folio_all(fi, bio) {
-		struct bch_folio *s = __bch2_folio(fi.folio);
-
-		if (atomic_dec_and_test(&s->write_count))
-			folio_end_writeback(fi.folio);
-	}
-
-	bio_put(&io->op.wbio.bio);
-}
-
-static void bch2_writepage_do_io(struct bch_writepage_state *w)
-{
-	struct bch_writepage_io *io = w->io;
-
-	w->io = NULL;
-	closure_call(&io->op.cl, bch2_write, NULL, NULL);
-}
-
-/*
- * Get a bch_writepage_io and add @page to it - appending to an existing one if
- * possible, else allocating a new one:
- */
-static void bch2_writepage_io_alloc(struct bch_fs *c,
-				    struct writeback_control *wbc,
-				    struct bch_writepage_state *w,
-				    struct bch_inode_info *inode,
-				    u64 sector,
-				    unsigned nr_replicas)
-{
-	struct bch_write_op *op;
-
-	w->io = container_of(bio_alloc_bioset(NULL, BIO_MAX_VECS,
-					      REQ_OP_WRITE,
-					      GFP_KERNEL,
-					      &c->writepage_bioset),
-			     struct bch_writepage_io, op.wbio.bio);
-
-	w->io->inode		= inode;
-	op			= &w->io->op;
-	bch2_write_op_init(op, c, w->opts);
-	op->target		= w->opts.foreground_target;
-	op->nr_replicas		= nr_replicas;
-	op->res.nr_replicas	= nr_replicas;
-	op->write_point		= writepoint_hashed(inode->ei_last_dirtied);
-	op->subvol		= inode->ei_subvol;
-	op->pos			= POS(inode->v.i_ino, sector);
-	op->end_io		= bch2_writepage_io_done;
-	op->devs_need_flush	= &inode->ei_devs_need_flush;
-	op->wbio.bio.bi_iter.bi_sector = sector;
-	op->wbio.bio.bi_opf	= wbc_to_write_flags(wbc);
-}
-
-static int __bch2_writepage(struct folio *folio,
-			    struct writeback_control *wbc,
-			    void *data)
-{
-	struct bch_inode_info *inode = to_bch_ei(folio->mapping->host);
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	struct bch_writepage_state *w = data;
-	struct bch_folio *s;
-	unsigned i, offset, f_sectors, nr_replicas_this_write = U32_MAX;
-	loff_t i_size = i_size_read(&inode->v);
-	int ret;
-
-	EBUG_ON(!folio_test_uptodate(folio));
-
-	/* Is the folio fully inside i_size? */
-	if (folio_end_pos(folio) <= i_size)
-		goto do_io;
-
-	/* Is the folio fully outside i_size? (truncate in progress) */
-	if (folio_pos(folio) >= i_size) {
-		folio_unlock(folio);
-		return 0;
-	}
-
-	/*
-	 * The folio straddles i_size.  It must be zeroed out on each and every
-	 * writepage invocation because it may be mmapped.  "A file is mapped
-	 * in multiples of the folio size.  For a file that is not a multiple of
-	 * the  folio size, the remaining memory is zeroed when mapped, and
-	 * writes to that region are not written out to the file."
-	 */
-	folio_zero_segment(folio,
-			   i_size - folio_pos(folio),
-			   folio_size(folio));
-do_io:
-	f_sectors = folio_sectors(folio);
-	s = bch2_folio(folio);
-
-	if (f_sectors > w->tmp_sectors) {
-		kfree(w->tmp);
-		w->tmp = kzalloc(sizeof(struct bch_folio_sector) *
-				 f_sectors, __GFP_NOFAIL);
-		w->tmp_sectors = f_sectors;
-	}
-
-	/*
-	 * Things get really hairy with errors during writeback:
-	 */
-	ret = bch2_get_folio_disk_reservation(c, inode, folio, false);
-	BUG_ON(ret);
-
-	/* Before unlocking the page, get copy of reservations: */
-	spin_lock(&s->lock);
-	memcpy(w->tmp, s->s, sizeof(struct bch_folio_sector) * f_sectors);
-
-	for (i = 0; i < f_sectors; i++) {
-		if (s->s[i].state < SECTOR_dirty)
-			continue;
-
-		nr_replicas_this_write =
-			min_t(unsigned, nr_replicas_this_write,
-			      s->s[i].nr_replicas +
-			      s->s[i].replicas_reserved);
-	}
-
-	for (i = 0; i < f_sectors; i++) {
-		if (s->s[i].state < SECTOR_dirty)
-			continue;
-
-		s->s[i].nr_replicas = w->opts.compression
-			? 0 : nr_replicas_this_write;
-
-		s->s[i].replicas_reserved = 0;
-		folio_sector_set(folio, s, i, SECTOR_allocated);
-	}
-	spin_unlock(&s->lock);
-
-	BUG_ON(atomic_read(&s->write_count));
-	atomic_set(&s->write_count, 1);
-
-	BUG_ON(folio_test_writeback(folio));
-	folio_start_writeback(folio);
-
-	folio_unlock(folio);
-
-	offset = 0;
-	while (1) {
-		unsigned sectors = 0, dirty_sectors = 0, reserved_sectors = 0;
-		u64 sector;
-
-		while (offset < f_sectors &&
-		       w->tmp[offset].state < SECTOR_dirty)
-			offset++;
-
-		if (offset == f_sectors)
-			break;
-
-		while (offset + sectors < f_sectors &&
-		       w->tmp[offset + sectors].state >= SECTOR_dirty) {
-			reserved_sectors += w->tmp[offset + sectors].replicas_reserved;
-			dirty_sectors += w->tmp[offset + sectors].state == SECTOR_dirty;
-			sectors++;
-		}
-		BUG_ON(!sectors);
-
-		sector = folio_sector(folio) + offset;
-
-		if (w->io &&
-		    (w->io->op.res.nr_replicas != nr_replicas_this_write ||
-		     bio_full(&w->io->op.wbio.bio, sectors << 9) ||
-		     w->io->op.wbio.bio.bi_iter.bi_size + (sectors << 9) >=
-		     (BIO_MAX_VECS * PAGE_SIZE) ||
-		     bio_end_sector(&w->io->op.wbio.bio) != sector))
-			bch2_writepage_do_io(w);
-
-		if (!w->io)
-			bch2_writepage_io_alloc(c, wbc, w, inode, sector,
-						nr_replicas_this_write);
-
-		atomic_inc(&s->write_count);
-
-		BUG_ON(inode != w->io->inode);
-		BUG_ON(!bio_add_folio(&w->io->op.wbio.bio, folio,
-				     sectors << 9, offset << 9));
-
-		/* Check for writing past i_size: */
-		WARN_ONCE((bio_end_sector(&w->io->op.wbio.bio) << 9) >
-			  round_up(i_size, block_bytes(c)) &&
-			  !test_bit(BCH_FS_EMERGENCY_RO, &c->flags),
-			  "writing past i_size: %llu > %llu (unrounded %llu)\n",
-			  bio_end_sector(&w->io->op.wbio.bio) << 9,
-			  round_up(i_size, block_bytes(c)),
-			  i_size);
-
-		w->io->op.res.sectors += reserved_sectors;
-		w->io->op.i_sectors_delta -= dirty_sectors;
-		w->io->op.new_i_size = i_size;
-
-		offset += sectors;
-	}
-
-	if (atomic_dec_and_test(&s->write_count))
-		folio_end_writeback(folio);
-
-	return 0;
-}
-
-int bch2_writepages(struct address_space *mapping, struct writeback_control *wbc)
-{
-	struct bch_fs *c = mapping->host->i_sb->s_fs_info;
-	struct bch_writepage_state w =
-		bch_writepage_state_init(c, to_bch_ei(mapping->host));
-	struct blk_plug plug;
-	int ret;
-
-	blk_start_plug(&plug);
-	ret = write_cache_pages(mapping, wbc, __bch2_writepage, &w);
-	if (w.io)
-		bch2_writepage_do_io(&w);
-	blk_finish_plug(&plug);
-	kfree(w.tmp);
-	return bch2_err_class(ret);
-}
-
-/* buffered writes: */
-
-int bch2_write_begin(struct file *file, struct address_space *mapping,
-		     loff_t pos, unsigned len,
-		     struct page **pagep, void **fsdata)
-{
-	struct bch_inode_info *inode = to_bch_ei(mapping->host);
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	struct bch2_folio_reservation *res;
-	struct folio *folio;
-	unsigned offset;
-	int ret = -ENOMEM;
-
-	res = kmalloc(sizeof(*res), GFP_KERNEL);
-	if (!res)
-		return -ENOMEM;
-
-	bch2_folio_reservation_init(c, inode, res);
-	*fsdata = res;
-
-	bch2_pagecache_add_get(inode);
-
-	folio = __filemap_get_folio(mapping, pos >> PAGE_SHIFT,
-				FGP_LOCK|FGP_WRITE|FGP_CREAT|FGP_STABLE,
-				mapping_gfp_mask(mapping));
-	if (IS_ERR_OR_NULL(folio))
-		goto err_unlock;
-
-	if (folio_test_uptodate(folio))
-		goto out;
-
-	offset = pos - folio_pos(folio);
-	len = min_t(size_t, len, folio_end_pos(folio) - pos);
-
-	/* If we're writing entire folio, don't need to read it in first: */
-	if (!offset && len == folio_size(folio))
-		goto out;
-
-	if (!offset && pos + len >= inode->v.i_size) {
-		folio_zero_segment(folio, len, folio_size(folio));
-		flush_dcache_folio(folio);
-		goto out;
-	}
-
-	if (folio_pos(folio) >= inode->v.i_size) {
-		folio_zero_segments(folio, 0, offset, offset + len, folio_size(folio));
-		flush_dcache_folio(folio);
-		goto out;
-	}
-readpage:
-	ret = bch2_read_single_folio(folio, mapping);
-	if (ret)
-		goto err;
-out:
-	ret = bch2_folio_set(c, inode_inum(inode), &folio, 1);
-	if (ret)
-		goto err;
-
-	ret = bch2_folio_reservation_get(c, inode, folio, res, offset, len);
-	if (ret) {
-		if (!folio_test_uptodate(folio)) {
-			/*
-			 * If the folio hasn't been read in, we won't know if we
-			 * actually need a reservation - we don't actually need
-			 * to read here, we just need to check if the folio is
-			 * fully backed by uncompressed data:
-			 */
-			goto readpage;
-		}
-
-		goto err;
-	}
-
-	*pagep = &folio->page;
-	return 0;
-err:
-	folio_unlock(folio);
-	folio_put(folio);
-	*pagep = NULL;
-err_unlock:
-	bch2_pagecache_add_put(inode);
-	kfree(res);
-	*fsdata = NULL;
-	return bch2_err_class(ret);
-}
-
-int bch2_write_end(struct file *file, struct address_space *mapping,
-		   loff_t pos, unsigned len, unsigned copied,
-		   struct page *page, void *fsdata)
-{
-	struct bch_inode_info *inode = to_bch_ei(mapping->host);
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	struct bch2_folio_reservation *res = fsdata;
-	struct folio *folio = page_folio(page);
-	unsigned offset = pos - folio_pos(folio);
-
-	lockdep_assert_held(&inode->v.i_rwsem);
-	BUG_ON(offset + copied > folio_size(folio));
-
-	if (unlikely(copied < len && !folio_test_uptodate(folio))) {
-		/*
-		 * The folio needs to be read in, but that would destroy
-		 * our partial write - simplest thing is to just force
-		 * userspace to redo the write:
-		 */
-		folio_zero_range(folio, 0, folio_size(folio));
-		flush_dcache_folio(folio);
-		copied = 0;
-	}
-
-	spin_lock(&inode->v.i_lock);
-	if (pos + copied > inode->v.i_size)
-		i_size_write(&inode->v, pos + copied);
-	spin_unlock(&inode->v.i_lock);
-
-	if (copied) {
-		if (!folio_test_uptodate(folio))
-			folio_mark_uptodate(folio);
-
-		bch2_set_folio_dirty(c, inode, folio, res, offset, copied);
-
-		inode->ei_last_dirtied = (unsigned long) current;
-	}
-
-	folio_unlock(folio);
-	folio_put(folio);
-	bch2_pagecache_add_put(inode);
-
-	bch2_folio_reservation_put(c, inode, res);
-	kfree(res);
-
-	return copied;
-}
-
-static noinline void folios_trunc(folios *folios, struct folio **fi)
-{
-	while (folios->data + folios->nr > fi) {
-		struct folio *f = darray_pop(folios);
-
-		folio_unlock(f);
-		folio_put(f);
-	}
-}
-
-static int __bch2_buffered_write(struct bch_inode_info *inode,
-				 struct address_space *mapping,
-				 struct iov_iter *iter,
-				 loff_t pos, unsigned len)
-{
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	struct bch2_folio_reservation res;
-	folios folios;
-	struct folio **fi, *f;
-	unsigned copied = 0, f_offset;
-	u64 end = pos + len, f_pos;
-	loff_t last_folio_pos = inode->v.i_size;
-	int ret = 0;
-
-	BUG_ON(!len);
-
-	bch2_folio_reservation_init(c, inode, &res);
-	darray_init(&folios);
-
-	ret = filemap_get_contig_folios_d(mapping, pos, end,
-				   FGP_LOCK|FGP_WRITE|FGP_STABLE|FGP_CREAT,
-				   mapping_gfp_mask(mapping),
-				   &folios);
-	if (ret)
-		goto out;
-
-	BUG_ON(!folios.nr);
-
-	f = darray_first(folios);
-	if (pos != folio_pos(f) && !folio_test_uptodate(f)) {
-		ret = bch2_read_single_folio(f, mapping);
-		if (ret)
-			goto out;
-	}
-
-	f = darray_last(folios);
-	end = min(end, folio_end_pos(f));
-	last_folio_pos = folio_pos(f);
-	if (end != folio_end_pos(f) && !folio_test_uptodate(f)) {
-		if (end >= inode->v.i_size) {
-			folio_zero_range(f, 0, folio_size(f));
-		} else {
-			ret = bch2_read_single_folio(f, mapping);
-			if (ret)
-				goto out;
-		}
-	}
-
-	ret = bch2_folio_set(c, inode_inum(inode), folios.data, folios.nr);
-	if (ret)
-		goto out;
-
-	f_pos = pos;
-	f_offset = pos - folio_pos(darray_first(folios));
-	darray_for_each(folios, fi) {
-		struct folio *f = *fi;
-		u64 f_len = min(end, folio_end_pos(f)) - f_pos;
-
-		/*
-		 * XXX: per POSIX and fstests generic/275, on -ENOSPC we're
-		 * supposed to write as much as we have disk space for.
-		 *
-		 * On failure here we should still write out a partial page if
-		 * we aren't completely out of disk space - we don't do that
-		 * yet:
-		 */
-		ret = bch2_folio_reservation_get(c, inode, f, &res, f_offset, f_len);
-		if (unlikely(ret)) {
-			folios_trunc(&folios, fi);
-			if (!folios.nr)
-				goto out;
-
-			end = min(end, folio_end_pos(darray_last(folios)));
-			break;
-		}
-
-		f_pos = folio_end_pos(f);
-		f_offset = 0;
-	}
-
-	if (mapping_writably_mapped(mapping))
-		darray_for_each(folios, fi)
-			flush_dcache_folio(*fi);
-
-	f_pos = pos;
-	f_offset = pos - folio_pos(darray_first(folios));
-	darray_for_each(folios, fi) {
-		struct folio *f = *fi;
-		u64 f_len = min(end, folio_end_pos(f)) - f_pos;
-		unsigned f_copied = copy_page_from_iter_atomic(&f->page, f_offset, f_len, iter);
-
-		if (!f_copied) {
-			folios_trunc(&folios, fi);
-			break;
-		}
-
-		if (!folio_test_uptodate(f) &&
-		    f_copied != folio_size(f) &&
-		    pos + copied + f_copied < inode->v.i_size) {
-			folio_zero_range(f, 0, folio_size(f));
-			folios_trunc(&folios, fi);
-			break;
-		}
-
-		flush_dcache_folio(f);
-		copied += f_copied;
-
-		if (f_copied != f_len) {
-			folios_trunc(&folios, fi + 1);
-			break;
-		}
-
-		f_pos = folio_end_pos(f);
-		f_offset = 0;
-	}
-
-	if (!copied)
-		goto out;
-
-	end = pos + copied;
-
-	spin_lock(&inode->v.i_lock);
-	if (end > inode->v.i_size)
-		i_size_write(&inode->v, end);
-	spin_unlock(&inode->v.i_lock);
-
-	f_pos = pos;
-	f_offset = pos - folio_pos(darray_first(folios));
-	darray_for_each(folios, fi) {
-		struct folio *f = *fi;
-		u64 f_len = min(end, folio_end_pos(f)) - f_pos;
-
-		if (!folio_test_uptodate(f))
-			folio_mark_uptodate(f);
-
-		bch2_set_folio_dirty(c, inode, f, &res, f_offset, f_len);
-
-		f_pos = folio_end_pos(f);
-		f_offset = 0;
-	}
-
-	inode->ei_last_dirtied = (unsigned long) current;
-out:
-	darray_for_each(folios, fi) {
-		folio_unlock(*fi);
-		folio_put(*fi);
-	}
-
-	/*
-	 * If the last folio added to the mapping starts beyond current EOF, we
-	 * performed a short write but left around at least one post-EOF folio.
-	 * Clean up the mapping before we return.
-	 */
-	if (last_folio_pos >= inode->v.i_size)
-		truncate_pagecache(&inode->v, inode->v.i_size);
-
-	darray_exit(&folios);
-	bch2_folio_reservation_put(c, inode, &res);
-
-	return copied ?: ret;
-}
-
-static ssize_t bch2_buffered_write(struct kiocb *iocb, struct iov_iter *iter)
-{
-	struct file *file = iocb->ki_filp;
-	struct address_space *mapping = file->f_mapping;
-	struct bch_inode_info *inode = file_bch_inode(file);
-	loff_t pos = iocb->ki_pos;
-	ssize_t written = 0;
-	int ret = 0;
-
-	bch2_pagecache_add_get(inode);
-
-	do {
-		unsigned offset = pos & (PAGE_SIZE - 1);
-		unsigned bytes = iov_iter_count(iter);
-again:
-		/*
-		 * Bring in the user page that we will copy from _first_.
-		 * Otherwise there's a nasty deadlock on copying from the
-		 * same page as we're writing to, without it being marked
-		 * up-to-date.
-		 *
-		 * 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.
-		 */
-		if (unlikely(fault_in_iov_iter_readable(iter, bytes))) {
-			bytes = min_t(unsigned long, iov_iter_count(iter),
-				      PAGE_SIZE - offset);
-
-			if (unlikely(fault_in_iov_iter_readable(iter, bytes))) {
-				ret = -EFAULT;
-				break;
-			}
-		}
-
-		if (unlikely(fatal_signal_pending(current))) {
-			ret = -EINTR;
-			break;
-		}
-
-		ret = __bch2_buffered_write(inode, mapping, iter, pos, bytes);
-		if (unlikely(ret < 0))
-			break;
-
-		cond_resched();
-
-		if (unlikely(ret == 0)) {
-			/*
-			 * If we were unable to copy any data at all, we must
-			 * fall back to a single segment length write.
-			 *
-			 * If we didn't fallback here, we could livelock
-			 * because not all segments in the iov can be copied at
-			 * once without a pagefault.
-			 */
-			bytes = min_t(unsigned long, PAGE_SIZE - offset,
-				      iov_iter_single_seg_count(iter));
-			goto again;
-		}
-		pos += ret;
-		written += ret;
-		ret = 0;
-
-		balance_dirty_pages_ratelimited(mapping);
-	} while (iov_iter_count(iter));
-
-	bch2_pagecache_add_put(inode);
-
-	return written ? written : ret;
-}
-
-/* O_DIRECT reads */
-
-static void bio_check_or_release(struct bio *bio, bool check_dirty)
-{
-	if (check_dirty) {
-		bio_check_pages_dirty(bio);
-	} else {
-		bio_release_pages(bio, false);
-		bio_put(bio);
-	}
-}
-
-static void bch2_dio_read_complete(struct closure *cl)
-{
-	struct dio_read *dio = container_of(cl, struct dio_read, cl);
-
-	dio->req->ki_complete(dio->req, dio->ret);
-	bio_check_or_release(&dio->rbio.bio, dio->should_dirty);
-}
-
-static void bch2_direct_IO_read_endio(struct bio *bio)
-{
-	struct dio_read *dio = bio->bi_private;
-
-	if (bio->bi_status)
-		dio->ret = blk_status_to_errno(bio->bi_status);
-
-	closure_put(&dio->cl);
-}
-
-static void bch2_direct_IO_read_split_endio(struct bio *bio)
-{
-	struct dio_read *dio = bio->bi_private;
-	bool should_dirty = dio->should_dirty;
-
-	bch2_direct_IO_read_endio(bio);
-	bio_check_or_release(bio, should_dirty);
-}
-
-static int bch2_direct_IO_read(struct kiocb *req, struct iov_iter *iter)
-{
-	struct file *file = req->ki_filp;
-	struct bch_inode_info *inode = file_bch_inode(file);
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	struct bch_io_opts opts;
-	struct dio_read *dio;
-	struct bio *bio;
-	loff_t offset = req->ki_pos;
-	bool sync = is_sync_kiocb(req);
-	size_t shorten;
-	ssize_t ret;
-
-	bch2_inode_opts_get(&opts, c, &inode->ei_inode);
-
-	if ((offset|iter->count) & (block_bytes(c) - 1))
-		return -EINVAL;
-
-	ret = min_t(loff_t, iter->count,
-		    max_t(loff_t, 0, i_size_read(&inode->v) - offset));
-
-	if (!ret)
-		return ret;
-
-	shorten = iov_iter_count(iter) - round_up(ret, block_bytes(c));
-	iter->count -= shorten;
-
-	bio = bio_alloc_bioset(NULL,
-			       bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
-			       REQ_OP_READ,
-			       GFP_KERNEL,
-			       &c->dio_read_bioset);
-
-	bio->bi_end_io = bch2_direct_IO_read_endio;
-
-	dio = container_of(bio, struct dio_read, rbio.bio);
-	closure_init(&dio->cl, NULL);
-
-	/*
-	 * this is a _really_ horrible hack just to avoid an atomic sub at the
-	 * end:
-	 */
-	if (!sync) {
-		set_closure_fn(&dio->cl, bch2_dio_read_complete, NULL);
-		atomic_set(&dio->cl.remaining,
-			   CLOSURE_REMAINING_INITIALIZER -
-			   CLOSURE_RUNNING +
-			   CLOSURE_DESTRUCTOR);
-	} else {
-		atomic_set(&dio->cl.remaining,
-			   CLOSURE_REMAINING_INITIALIZER + 1);
-	}
-
-	dio->req	= req;
-	dio->ret	= ret;
-	/*
-	 * This is one of the sketchier things I've encountered: we have to skip
-	 * the dirtying of requests that are internal from the kernel (i.e. from
-	 * loopback), because we'll deadlock on page_lock.
-	 */
-	dio->should_dirty = iter_is_iovec(iter);
-
-	goto start;
-	while (iter->count) {
-		bio = bio_alloc_bioset(NULL,
-				       bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
-				       REQ_OP_READ,
-				       GFP_KERNEL,
-				       &c->bio_read);
-		bio->bi_end_io		= bch2_direct_IO_read_split_endio;
-start:
-		bio->bi_opf		= REQ_OP_READ|REQ_SYNC;
-		bio->bi_iter.bi_sector	= offset >> 9;
-		bio->bi_private		= dio;
-
-		ret = bio_iov_iter_get_pages(bio, iter);
-		if (ret < 0) {
-			/* XXX: fault inject this path */
-			bio->bi_status = BLK_STS_RESOURCE;
-			bio_endio(bio);
-			break;
-		}
-
-		offset += bio->bi_iter.bi_size;
-
-		if (dio->should_dirty)
-			bio_set_pages_dirty(bio);
-
-		if (iter->count)
-			closure_get(&dio->cl);
-
-		bch2_read(c, rbio_init(bio, opts), inode_inum(inode));
-	}
-
-	iter->count += shorten;
-
-	if (sync) {
-		closure_sync(&dio->cl);
-		closure_debug_destroy(&dio->cl);
-		ret = dio->ret;
-		bio_check_or_release(&dio->rbio.bio, dio->should_dirty);
-		return ret;
-	} else {
-		return -EIOCBQUEUED;
-	}
-}
-
-ssize_t bch2_read_iter(struct kiocb *iocb, struct iov_iter *iter)
-{
-	struct file *file = iocb->ki_filp;
-	struct bch_inode_info *inode = file_bch_inode(file);
-	struct address_space *mapping = file->f_mapping;
-	size_t count = iov_iter_count(iter);
-	ssize_t ret;
-
-	if (!count)
-		return 0; /* skip atime */
-
-	if (iocb->ki_flags & IOCB_DIRECT) {
-		struct blk_plug plug;
-
-		if (unlikely(mapping->nrpages)) {
-			ret = filemap_write_and_wait_range(mapping,
-						iocb->ki_pos,
-						iocb->ki_pos + count - 1);
-			if (ret < 0)
-				goto out;
-		}
-
-		file_accessed(file);
-
-		blk_start_plug(&plug);
-		ret = bch2_direct_IO_read(iocb, iter);
-		blk_finish_plug(&plug);
-
-		if (ret >= 0)
-			iocb->ki_pos += ret;
-	} else {
-		bch2_pagecache_add_get(inode);
-		ret = generic_file_read_iter(iocb, iter);
-		bch2_pagecache_add_put(inode);
-	}
-out:
-	return bch2_err_class(ret);
-}
-
-/* O_DIRECT writes */
-
-static bool bch2_check_range_allocated(struct bch_fs *c, subvol_inum inum,
-				       u64 offset, u64 size,
-				       unsigned nr_replicas, bool compressed)
-{
-	struct btree_trans trans;
-	struct btree_iter iter;
-	struct bkey_s_c k;
-	u64 end = offset + size;
-	u32 snapshot;
-	bool ret = true;
-	int err;
-
-	bch2_trans_init(&trans, c, 0, 0);
-retry:
-	bch2_trans_begin(&trans);
-
-	err = bch2_subvolume_get_snapshot(&trans, inum.subvol, &snapshot);
-	if (err)
-		goto err;
-
-	for_each_btree_key_norestart(&trans, iter, BTREE_ID_extents,
-			   SPOS(inum.inum, offset, snapshot),
-			   BTREE_ITER_SLOTS, k, err) {
-		if (bkey_ge(bkey_start_pos(k.k), POS(inum.inum, end)))
-			break;
-
-		if (k.k->p.snapshot != snapshot ||
-		    nr_replicas > bch2_bkey_replicas(c, k) ||
-		    (!compressed && bch2_bkey_sectors_compressed(k))) {
-			ret = false;
-			break;
-		}
-	}
-
-	offset = iter.pos.offset;
-	bch2_trans_iter_exit(&trans, &iter);
-err:
-	if (bch2_err_matches(err, BCH_ERR_transaction_restart))
-		goto retry;
-	bch2_trans_exit(&trans);
-
-	return err ? false : ret;
-}
-
-static noinline bool bch2_dio_write_check_allocated(struct dio_write *dio)
-{
-	struct bch_fs *c = dio->op.c;
-	struct bch_inode_info *inode = dio->inode;
-	struct bio *bio = &dio->op.wbio.bio;
-
-	return bch2_check_range_allocated(c, inode_inum(inode),
-				dio->op.pos.offset, bio_sectors(bio),
-				dio->op.opts.data_replicas,
-				dio->op.opts.compression != 0);
-}
-
-static void bch2_dio_write_loop_async(struct bch_write_op *);
-static __always_inline long bch2_dio_write_done(struct dio_write *dio);
-
-/*
- * We're going to return -EIOCBQUEUED, but we haven't finished consuming the
- * iov_iter yet, so we need to stash a copy of the iovec: it might be on the
- * caller's stack, we're not guaranteed that it will live for the duration of
- * the IO:
- */
-static noinline int bch2_dio_write_copy_iov(struct dio_write *dio)
-{
-	struct iovec *iov = dio->inline_vecs;
-
-	/*
-	 * iov_iter has a single embedded iovec - nothing to do:
-	 */
-	if (iter_is_ubuf(&dio->iter))
-		return 0;
-
-	/*
-	 * We don't currently handle non-iovec iov_iters here - return an error,
-	 * and we'll fall back to doing the IO synchronously:
-	 */
-	if (!iter_is_iovec(&dio->iter))
-		return -1;
-
-	if (dio->iter.nr_segs > ARRAY_SIZE(dio->inline_vecs)) {
-		iov = kmalloc_array(dio->iter.nr_segs, sizeof(*iov),
-				    GFP_KERNEL);
-		if (unlikely(!iov))
-			return -ENOMEM;
-
-		dio->free_iov = true;
-	}
-
-	memcpy(iov, dio->iter.__iov, dio->iter.nr_segs * sizeof(*iov));
-	dio->iter.__iov = iov;
-	return 0;
-}
-
-static void bch2_dio_write_flush_done(struct closure *cl)
-{
-	struct dio_write *dio = container_of(cl, struct dio_write, op.cl);
-	struct bch_fs *c = dio->op.c;
-
-	closure_debug_destroy(cl);
-
-	dio->op.error = bch2_journal_error(&c->journal);
-
-	bch2_dio_write_done(dio);
-}
-
-static noinline void bch2_dio_write_flush(struct dio_write *dio)
-{
-	struct bch_fs *c = dio->op.c;
-	struct bch_inode_unpacked inode;
-	int ret;
-
-	dio->flush = 0;
-
-	closure_init(&dio->op.cl, NULL);
-
-	if (!dio->op.error) {
-		ret = bch2_inode_find_by_inum(c, inode_inum(dio->inode), &inode);
-		if (ret) {
-			dio->op.error = ret;
-		} else {
-			bch2_journal_flush_seq_async(&c->journal, inode.bi_journal_seq, &dio->op.cl);
-			bch2_inode_flush_nocow_writes_async(c, dio->inode, &dio->op.cl);
-		}
-	}
-
-	if (dio->sync) {
-		closure_sync(&dio->op.cl);
-		closure_debug_destroy(&dio->op.cl);
-	} else {
-		continue_at(&dio->op.cl, bch2_dio_write_flush_done, NULL);
-	}
-}
-
-static __always_inline long bch2_dio_write_done(struct dio_write *dio)
-{
-	struct kiocb *req = dio->req;
-	struct bch_inode_info *inode = dio->inode;
-	bool sync = dio->sync;
-	long ret;
-
-	if (unlikely(dio->flush)) {
-		bch2_dio_write_flush(dio);
-		if (!sync)
-			return -EIOCBQUEUED;
-	}
-
-	bch2_pagecache_block_put(inode);
-
-	if (dio->free_iov)
-		kfree(dio->iter.__iov);
-
-	ret = dio->op.error ?: ((long) dio->written << 9);
-	bio_put(&dio->op.wbio.bio);
-
-	/* inode->i_dio_count is our ref on inode and thus bch_fs */
-	inode_dio_end(&inode->v);
-
-	if (ret < 0)
-		ret = bch2_err_class(ret);
-
-	if (!sync) {
-		req->ki_complete(req, ret);
-		ret = -EIOCBQUEUED;
-	}
-	return ret;
-}
-
-static __always_inline void bch2_dio_write_end(struct dio_write *dio)
-{
-	struct bch_fs *c = dio->op.c;
-	struct kiocb *req = dio->req;
-	struct bch_inode_info *inode = dio->inode;
-	struct bio *bio = &dio->op.wbio.bio;
-
-	req->ki_pos	+= (u64) dio->op.written << 9;
-	dio->written	+= dio->op.written;
-
-	if (dio->extending) {
-		spin_lock(&inode->v.i_lock);
-		if (req->ki_pos > inode->v.i_size)
-			i_size_write(&inode->v, req->ki_pos);
-		spin_unlock(&inode->v.i_lock);
-	}
-
-	if (dio->op.i_sectors_delta || dio->quota_res.sectors) {
-		mutex_lock(&inode->ei_quota_lock);
-		__i_sectors_acct(c, inode, &dio->quota_res, dio->op.i_sectors_delta);
-		__bch2_quota_reservation_put(c, inode, &dio->quota_res);
-		mutex_unlock(&inode->ei_quota_lock);
-	}
-
-	bio_release_pages(bio, false);
-
-	if (unlikely(dio->op.error))
-		set_bit(EI_INODE_ERROR, &inode->ei_flags);
-}
-
-static __always_inline long bch2_dio_write_loop(struct dio_write *dio)
-{
-	struct bch_fs *c = dio->op.c;
-	struct kiocb *req = dio->req;
-	struct address_space *mapping = dio->mapping;
-	struct bch_inode_info *inode = dio->inode;
-	struct bch_io_opts opts;
-	struct bio *bio = &dio->op.wbio.bio;
-	unsigned unaligned, iter_count;
-	bool sync = dio->sync, dropped_locks;
-	long ret;
-
-	bch2_inode_opts_get(&opts, c, &inode->ei_inode);
-
-	while (1) {
-		iter_count = dio->iter.count;
-
-		EBUG_ON(current->faults_disabled_mapping);
-		current->faults_disabled_mapping = mapping;
-
-		ret = bio_iov_iter_get_pages(bio, &dio->iter);
-
-		dropped_locks = fdm_dropped_locks();
-
-		current->faults_disabled_mapping = NULL;
-
-		/*
-		 * If the fault handler returned an error but also signalled
-		 * that it dropped & retook ei_pagecache_lock, we just need to
-		 * re-shoot down the page cache and retry:
-		 */
-		if (dropped_locks && ret)
-			ret = 0;
-
-		if (unlikely(ret < 0))
-			goto err;
-
-		if (unlikely(dropped_locks)) {
-			ret = write_invalidate_inode_pages_range(mapping,
-					req->ki_pos,
-					req->ki_pos + iter_count - 1);
-			if (unlikely(ret))
-				goto err;
-
-			if (!bio->bi_iter.bi_size)
-				continue;
-		}
-
-		unaligned = bio->bi_iter.bi_size & (block_bytes(c) - 1);
-		bio->bi_iter.bi_size -= unaligned;
-		iov_iter_revert(&dio->iter, unaligned);
-
-		if (!bio->bi_iter.bi_size) {
-			/*
-			 * bio_iov_iter_get_pages was only able to get <
-			 * blocksize worth of pages:
-			 */
-			ret = -EFAULT;
-			goto err;
-		}
-
-		bch2_write_op_init(&dio->op, c, opts);
-		dio->op.end_io		= sync
-			? NULL
-			: bch2_dio_write_loop_async;
-		dio->op.target		= dio->op.opts.foreground_target;
-		dio->op.write_point	= writepoint_hashed((unsigned long) current);
-		dio->op.nr_replicas	= dio->op.opts.data_replicas;
-		dio->op.subvol		= inode->ei_subvol;
-		dio->op.pos		= POS(inode->v.i_ino, (u64) req->ki_pos >> 9);
-		dio->op.devs_need_flush	= &inode->ei_devs_need_flush;
-
-		if (sync)
-			dio->op.flags |= BCH_WRITE_SYNC;
-		dio->op.flags |= BCH_WRITE_CHECK_ENOSPC;
-
-		ret = bch2_quota_reservation_add(c, inode, &dio->quota_res,
-						 bio_sectors(bio), true);
-		if (unlikely(ret))
-			goto err;
-
-		ret = bch2_disk_reservation_get(c, &dio->op.res, bio_sectors(bio),
-						dio->op.opts.data_replicas, 0);
-		if (unlikely(ret) &&
-		    !bch2_dio_write_check_allocated(dio))
-			goto err;
-
-		task_io_account_write(bio->bi_iter.bi_size);
-
-		if (unlikely(dio->iter.count) &&
-		    !dio->sync &&
-		    !dio->loop &&
-		    bch2_dio_write_copy_iov(dio))
-			dio->sync = sync = true;
-
-		dio->loop = true;
-		closure_call(&dio->op.cl, bch2_write, NULL, NULL);
-
-		if (!sync)
-			return -EIOCBQUEUED;
-
-		bch2_dio_write_end(dio);
-
-		if (likely(!dio->iter.count) || dio->op.error)
-			break;
-
-		bio_reset(bio, NULL, REQ_OP_WRITE);
-	}
-out:
-	return bch2_dio_write_done(dio);
-err:
-	dio->op.error = ret;
-
-	bio_release_pages(bio, false);
-
-	bch2_quota_reservation_put(c, inode, &dio->quota_res);
-	goto out;
-}
-
-static noinline __cold void bch2_dio_write_continue(struct dio_write *dio)
-{
-	struct mm_struct *mm = dio->mm;
-
-	bio_reset(&dio->op.wbio.bio, NULL, REQ_OP_WRITE);
-
-	if (mm)
-		kthread_use_mm(mm);
-	bch2_dio_write_loop(dio);
-	if (mm)
-		kthread_unuse_mm(mm);
-}
-
-static void bch2_dio_write_loop_async(struct bch_write_op *op)
-{
-	struct dio_write *dio = container_of(op, struct dio_write, op);
-
-	bch2_dio_write_end(dio);
-
-	if (likely(!dio->iter.count) || dio->op.error)
-		bch2_dio_write_done(dio);
-	else
-		bch2_dio_write_continue(dio);
-}
-
-static noinline
-ssize_t bch2_direct_write(struct kiocb *req, struct iov_iter *iter)
-{
-	struct file *file = req->ki_filp;
-	struct address_space *mapping = file->f_mapping;
-	struct bch_inode_info *inode = file_bch_inode(file);
-	struct bch_fs *c = inode->v.i_sb->s_fs_info;
-	struct dio_write *dio;
-	struct bio *bio;
-	bool locked = true, extending;
-	ssize_t ret;
-
-	prefetch(&c->opts);
-	prefetch((void *) &c->opts + 64);
-	prefetch(&inode->ei_inode);
-	prefetch((void *) &inode->ei_inode + 64);
-
-	inode_lock(&inode->v);
-
-	ret = generic_write_checks(req, iter);
-	if (unlikely(ret <= 0))
-		goto err;
-
-	ret = file_remove_privs(file);
-	if (unlikely(ret))
-		goto err;
-
-	ret = file_update_time(file);
-	if (unlikely(ret))
-		goto err;
-
-	if (unlikely((req->ki_pos|iter->count) & (block_bytes(c) - 1)))
-		goto err;
-
-	inode_dio_begin(&inode->v);
-	bch2_pagecache_block_get(inode);
-
-	extending = req->ki_pos + iter->count > inode->v.i_size;
-	if (!extending) {
-		inode_unlock(&inode->v);
-		locked = false;
-	}
-
-	bio = bio_alloc_bioset(NULL,
-			       bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
-			       REQ_OP_WRITE,
-			       GFP_KERNEL,
-			       &c->dio_write_bioset);
-	dio = container_of(bio, struct dio_write, op.wbio.bio);
-	dio->req		= req;
-	dio->mapping		= mapping;
-	dio->inode		= inode;
-	dio->mm			= current->mm;
-	dio->loop		= false;
-	dio->extending		= extending;
-	dio->sync		= is_sync_kiocb(req) || extending;
-	dio->flush		= iocb_is_dsync(req) && !c->opts.journal_flush_disabled;
-	dio->free_iov		= false;
-	dio->quota_res.sectors	= 0;
-	dio->written		= 0;
-	dio->iter		= *iter;
-	dio->op.c		= c;
-
-	if (unlikely(mapping->nrpages)) {
-		ret = write_invalidate_inode_pages_range(mapping,
-						req->ki_pos,
-						req->ki_pos + iter->count - 1);
-		if (unlikely(ret))
-			goto err_put_bio;
-	}
-
-	ret = bch2_dio_write_loop(dio);
-err:
-	if (locked)
-		inode_unlock(&inode->v);
-	return ret;
-err_put_bio:
-	bch2_pagecache_block_put(inode);
-	bio_put(bio);
-	inode_dio_end(&inode->v);
-	goto err;
-}
-
-ssize_t bch2_write_iter(struct kiocb *iocb, struct iov_iter *from)
-{
-	struct file *file = iocb->ki_filp;
-	struct bch_inode_info *inode = file_bch_inode(file);
-	ssize_t	ret;
-
-	if (iocb->ki_flags & IOCB_DIRECT) {
-		ret = bch2_direct_write(iocb, from);
-		goto out;
-	}
-
-	inode_lock(&inode->v);
-
-	ret = generic_write_checks(iocb, from);
-	if (ret <= 0)
-		goto unlock;
-
-	ret = file_remove_privs(file);
-	if (ret)
-		goto unlock;
-
-	ret = file_update_time(file);
-	if (ret)
-		goto unlock;
-
-	ret = bch2_buffered_write(iocb, from);
-	if (likely(ret > 0))
-		iocb->ki_pos += ret;
-unlock:
-	inode_unlock(&inode->v);
-
-	if (ret > 0)
-		ret = generic_write_sync(iocb, ret);
-out:
-	return bch2_err_class(ret);
 }
 
 /* fsync: */
···
 		s->s[i].nr_replicas	= 0;
 
 		i_sectors_delta -= s->s[i].state == SECTOR_dirty;
-		folio_sector_set(folio, s, i, SECTOR_unallocated);
+		bch2_folio_sector_set(folio, s, i, SECTOR_unallocated);
 	}
 
-	i_sectors_acct(c, inode, NULL, i_sectors_delta);
+	bch2_i_sectors_acct(c, inode, NULL, i_sectors_delta);
 
 	/*
 	 * Caller needs to know whether this folio will be written out by
···
 	ret = bch2_fpunch(c, inode_inum(inode),
 			round_up(iattr->ia_size, block_bytes(c)) >> 9,
 			U64_MAX, &i_sectors_delta);
-	i_sectors_acct(c, inode, NULL, i_sectors_delta);
+	bch2_i_sectors_acct(c, inode, NULL, i_sectors_delta);
 
 	bch2_fs_inconsistent_on(!inode->v.i_size && inode->v.i_blocks &&
 				!bch2_journal_error(&c->journal), c,
···
 		ret = bch2_fpunch(c, inode_inum(inode),
 				  block_start >> 9, block_end >> 9,
 				  &i_sectors_delta);
-		i_sectors_acct(c, inode, NULL, i_sectors_delta);
+		bch2_i_sectors_acct(c, inode, NULL, i_sectors_delta);
 	}
 
 	mutex_lock(&inode->ei_update_lock);
···
 
 	new_size = inode->v.i_size + shift;
 
-	ret = write_invalidate_inode_pages_range(mapping, offset, LLONG_MAX);
+	ret = bch2_write_invalidate_inode_pages_range(mapping, offset, LLONG_MAX);
 	if (ret)
 		return ret;
 
···
 		ret = bch2_fpunch(c, inode_inum(inode),
 				  offset >> 9, (offset + len) >> 9,
 				  &i_sectors_delta);
-		i_sectors_acct(c, inode, NULL, i_sectors_delta);
+		bch2_i_sectors_acct(c, inode, NULL, i_sectors_delta);
 
 		if (ret)
 			return ret;
···
 		if (ret)
 			goto bkey_err;
 
-		i_sectors_acct(c, inode, &quota_res, i_sectors_delta);
+		bch2_i_sectors_acct(c, inode, &quota_res, i_sectors_delta);
 
 		drop_locks_do(&trans,
-			(mark_pagecache_reserved(inode, hole_start, iter.pos.offset), 0));
+			(bch2_mark_pagecache_reserved(inode, hole_start, iter.pos.offset), 0));
 bkey_err:
 		bch2_quota_reservation_put(c, inode, &quota_res);
 		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
···
 
 		bch2_fpunch_at(&trans, &iter, inode_inum(inode),
 			       end_sector, &i_sectors_delta);
-		i_sectors_acct(c, inode, &quota_res, i_sectors_delta);
+		bch2_i_sectors_acct(c, inode, &quota_res, i_sectors_delta);
 		bch2_quota_reservation_put(c, inode, &quota_res);
 	}
 
···
 
 	aligned_len = round_up((u64) len, block_bytes(c));
 
-	ret = write_invalidate_inode_pages_range(dst->v.i_mapping,
+	ret = bch2_write_invalidate_inode_pages_range(dst->v.i_mapping,
 				pos_dst, pos_dst + len - 1);
 	if (ret)
 		goto err;
···
 
 	file_update_time(file_dst);
 
-	mark_pagecache_unallocated(src, pos_src >> 9,
+	bch2_mark_pagecache_unallocated(src, pos_src >> 9,
 				   (pos_src + aligned_len) >> 9);
 
 	ret = bch2_remap_range(c,
···
 	 */
 	ret = min((u64) ret << 9, (u64) len);
 
-	i_sectors_acct(c, dst, &quota_res, i_sectors_delta);
+	bch2_i_sectors_acct(c, dst, &quota_res, i_sectors_delta);
 
 	spin_lock(&dst->v.i_lock);
 	if (pos_dst + ret > dst->v.i_size)
···
 }
 
 /* fseek: */
-
-static int folio_data_offset(struct folio *folio, loff_t pos,
-			     unsigned min_replicas)
-{
-	struct bch_folio *s = bch2_folio(folio);
-	unsigned i, sectors = folio_sectors(folio);
-
-	if (s)
-		for (i = folio_pos_to_s(folio, pos); i < sectors; i++)
-			if (s->s[i].state >= SECTOR_dirty &&
-			    s->s[i].nr_replicas + s->s[i].replicas_reserved >= min_replicas)
-				return i << SECTOR_SHIFT;
-
-	return -1;
-}
-
-static loff_t bch2_seek_pagecache_data(struct inode *vinode,
-				       loff_t start_offset,
-				       loff_t end_offset,
-				       unsigned min_replicas,
-				       bool nonblock)
-{
-	struct folio_batch fbatch;
-	pgoff_t start_index	= start_offset >> PAGE_SHIFT;
-	pgoff_t end_index	= end_offset >> PAGE_SHIFT;
-	pgoff_t index		= start_index;
-	unsigned i;
-	loff_t ret;
-	int offset;
-
-	folio_batch_init(&fbatch);
-
-	while (filemap_get_folios(vinode->i_mapping,
-				  &index, end_index, &fbatch)) {
-		for (i = 0; i < folio_batch_count(&fbatch); i++) {
-			struct folio *folio = fbatch.folios[i];
-
-			if (!nonblock) {
-				folio_lock(folio);
-			} else if (!folio_trylock(folio)) {
-				folio_batch_release(&fbatch);
-				return -EAGAIN;
-			}
-
-			offset = folio_data_offset(folio,
-					max(folio_pos(folio), start_offset),
-					min_replicas);
-			if (offset >= 0) {
-				ret = clamp(folio_pos(folio) + offset,
-					    start_offset, end_offset);
-				folio_unlock(folio);
-				folio_batch_release(&fbatch);
-				return ret;
-			}
-			folio_unlock(folio);
-		}
-		folio_batch_release(&fbatch);
-		cond_resched();
-	}
-
-	return end_offset;
-}
 
 static loff_t bch2_seek_data(struct file *file, u64 offset)
 {
···
 		return -ENXIO;
 
 	return vfs_setpos(file, next_data, MAX_LFS_FILESIZE);
-}
-
-static int folio_hole_offset(struct address_space *mapping, loff_t *offset,
-			      unsigned min_replicas, bool nonblock)
-{
-	struct folio *folio;
-	struct bch_folio *s;
-	unsigned i, sectors;
-	bool ret = true;
-
-	folio = __filemap_get_folio(mapping, *offset >> PAGE_SHIFT,
-				    FGP_LOCK|(nonblock ? FGP_NOWAIT : 0), 0);
-	if (folio == ERR_PTR(-EAGAIN))
-		return -EAGAIN;
-	if (IS_ERR_OR_NULL(folio))
-		return true;
-
-	s = bch2_folio(folio);
-	if (!s)
-		goto unlock;
-
-	sectors = folio_sectors(folio);
-	for (i = folio_pos_to_s(folio, *offset); i < sectors; i++)
-		if (s->s[i].state < SECTOR_dirty ||
-		    s->s[i].nr_replicas + s->s[i].replicas_reserved < min_replicas) {
-			*offset = max(*offset,
-				      folio_pos(folio) + (i << SECTOR_SHIFT));
-			goto unlock;
-		}
-
-	*offset = folio_end_pos(folio);
-	ret = false;
-unlock:
-	folio_unlock(folio);
-	folio_put(folio);
-	return ret;
-}
-
-static loff_t bch2_seek_pagecache_hole(struct inode *vinode,
-				       loff_t start_offset,
-				       loff_t end_offset,
-				       unsigned min_replicas,
-				       bool nonblock)
-{
-	struct address_space *mapping = vinode->i_mapping;
-	loff_t offset = start_offset;
-
-	while (offset < end_offset &&
-	       !folio_hole_offset(mapping, &offset, min_replicas, nonblock))
-		;
-
-	return min(offset, end_offset);
-}
-
-static int bch2_clamp_data_hole(struct inode *inode,
-				u64 *hole_start,
-				u64 *hole_end,
-				unsigned min_replicas,
-				bool nonblock)
-{
-	loff_t ret;
-
-	ret = bch2_seek_pagecache_hole(inode,
-		*hole_start << 9, *hole_end << 9, min_replicas, nonblock) >> 9;
-	if (ret < 0)
-		return ret;
-
-	*hole_start = ret;
-
-	if (*hole_start == *hole_end)
-		return 0;
-
-	ret = bch2_seek_pagecache_data(inode,
-		*hole_start << 9, *hole_end << 9, min_replicas, nonblock) >> 9;
-	if (ret < 0)
-		return ret;
-
-	*hole_end = ret;
-	return 0;
 }
 
 static loff_t bch2_seek_hole(struct file *file, u64 offset)
···
 void bch2_fs_fsio_exit(struct bch_fs *c)
 {
 	bioset_exit(&c->nocow_flush_bioset);
-	bioset_exit(&c->dio_write_bioset);
-	bioset_exit(&c->dio_read_bioset);
-	bioset_exit(&c->writepage_bioset);
 }
 
 int bch2_fs_fsio_init(struct bch_fs *c)
 {
-	if (bioset_init(&c->writepage_bioset,
-			4, offsetof(struct bch_writepage_io, op.wbio.bio),
-			BIOSET_NEED_BVECS))
-		return -BCH_ERR_ENOMEM_writepage_bioset_init;
-
-	if (bioset_init(&c->dio_read_bioset,
-			4, offsetof(struct dio_read, rbio.bio),
-			BIOSET_NEED_BVECS))
-		return -BCH_ERR_ENOMEM_dio_read_bioset_init;
-
-	if (bioset_init(&c->dio_write_bioset,
-			4, offsetof(struct dio_write, op.wbio.bio),
-			BIOSET_NEED_BVECS))
-		return -BCH_ERR_ENOMEM_dio_write_bioset_init;
-
 	if (bioset_init(&c->nocow_flush_bioset,
 			1, offsetof(struct nocow_flush, bio), 0))
 		return -BCH_ERR_ENOMEM_nocow_flush_bioset_init;

fs/bcachefs/fs-io.h

···
 #ifndef NO_BCACHEFS_FS
 
 #include "buckets.h"
+#include "fs.h"
 #include "io_types.h"
+#include "quota.h"
 
 #include <linux/uio.h>
 
-struct quota_res;
+struct folio_vec {
+	struct folio	*fv_folio;
+	size_t		fv_offset;
+	size_t		fv_len;
+};
+
+static inline struct folio_vec biovec_to_foliovec(struct bio_vec bv)
+{
+
+	struct folio *folio	= page_folio(bv.bv_page);
+	size_t offset		= (folio_page_idx(folio, bv.bv_page) << PAGE_SHIFT) +
+		bv.bv_offset;
+	size_t len = min_t(size_t, folio_size(folio) - offset, bv.bv_len);
+
+	return (struct folio_vec) {
+		.fv_folio	= folio,
+		.fv_offset	= offset,
+		.fv_len		= len,
+	};
+}
+
+static inline struct folio_vec bio_iter_iovec_folio(struct bio *bio,
+						    struct bvec_iter iter)
+{
+	return biovec_to_foliovec(bio_iter_iovec(bio, iter));
+}
+
+#define __bio_for_each_folio(bvl, bio, iter, start)			\
+	for (iter = (start);						\
+	     (iter).bi_size &&						\
+		((bvl = bio_iter_iovec_folio((bio), (iter))), 1);	\
+	     bio_advance_iter_single((bio), &(iter), (bvl).fv_len))
+
+/**
+ * bio_for_each_folio - iterate over folios within a bio
+ *
+ * Like other non-_all versions, this iterates over what bio->bi_iter currently
+ * points to. This version is for drivers, where the bio may have previously
+ * been split or cloned.
+ */
+#define bio_for_each_folio(bvl, bio, iter)				\
+	__bio_for_each_folio(bvl, bio, iter, (bio)->bi_iter)
+
+struct quota_res {
+	u64				sectors;
+};
+
+#ifdef CONFIG_BCACHEFS_QUOTA
+
+static inline void __bch2_quota_reservation_put(struct bch_fs *c,
+					 struct bch_inode_info *inode,
+					 struct quota_res *res)
+{
+	BUG_ON(res->sectors > inode->ei_quota_reserved);
+
+	bch2_quota_acct(c, inode->ei_qid, Q_SPC,
+			-((s64) res->sectors), KEY_TYPE_QUOTA_PREALLOC);
+	inode->ei_quota_reserved -= res->sectors;
+	res->sectors = 0;
+}
+
+static inline void bch2_quota_reservation_put(struct bch_fs *c,
+				       struct bch_inode_info *inode,
+				       struct quota_res *res)
+{
+	if (res->sectors) {
+		mutex_lock(&inode->ei_quota_lock);
+		__bch2_quota_reservation_put(c, inode, res);
+		mutex_unlock(&inode->ei_quota_lock);
+	}
+}
+
+static inline int bch2_quota_reservation_add(struct bch_fs *c,
+				      struct bch_inode_info *inode,
+				      struct quota_res *res,
+				      u64 sectors,
+				      bool check_enospc)
+{
+	int ret;
+
+	if (test_bit(EI_INODE_SNAPSHOT, &inode->ei_flags))
+		return 0;
+
+	mutex_lock(&inode->ei_quota_lock);
+	ret = bch2_quota_acct(c, inode->ei_qid, Q_SPC, sectors,
+			      check_enospc ? KEY_TYPE_QUOTA_PREALLOC : KEY_TYPE_QUOTA_NOCHECK);
+	if (likely(!ret)) {
+		inode->ei_quota_reserved += sectors;
+		res->sectors += sectors;
+	}
+	mutex_unlock(&inode->ei_quota_lock);
+
+	return ret;
+}
+
+#else
+
+static inline void __bch2_quota_reservation_put(struct bch_fs *c,
+					 struct bch_inode_info *inode,
+					 struct quota_res *res) {}
+
+static inline void bch2_quota_reservation_put(struct bch_fs *c,
+				       struct bch_inode_info *inode,
+				       struct quota_res *res) {}
+
+static inline int bch2_quota_reservation_add(struct bch_fs *c,
+				      struct bch_inode_info *inode,
+				      struct quota_res *res,
+				      unsigned sectors,
+				      bool check_enospc)
+{
+	return 0;
+}
+
+#endif
+
+void __bch2_i_sectors_acct(struct bch_fs *, struct bch_inode_info *,
+			   struct quota_res *, s64);
+
+static inline void bch2_i_sectors_acct(struct bch_fs *c, struct bch_inode_info *inode,
+				       struct quota_res *quota_res, s64 sectors)
+{
+	if (sectors) {
+		mutex_lock(&inode->ei_quota_lock);
+		__bch2_i_sectors_acct(c, inode, quota_res, sectors);
+		mutex_unlock(&inode->ei_quota_lock);
+	}
+}
+
+static inline struct address_space *faults_disabled_mapping(void)
+{
+	return (void *) (((unsigned long) current->faults_disabled_mapping) & ~1UL);
+}
+
+static inline void set_fdm_dropped_locks(void)
+{
+	current->faults_disabled_mapping =
+		(void *) (((unsigned long) current->faults_disabled_mapping)|1);
+}
+
+static inline bool fdm_dropped_locks(void)
+{
+	return ((unsigned long) current->faults_disabled_mapping) & 1;
+}
+
+void bch2_inode_flush_nocow_writes_async(struct bch_fs *,
+			struct bch_inode_info *, struct closure *);
 
 int __must_check bch2_write_inode_size(struct bch_fs *,
 				       struct bch_inode_info *,
 				       loff_t, unsigned);
-
-int bch2_read_folio(struct file *, struct folio *);
-
-int bch2_writepages(struct address_space *, struct writeback_control *);
-void bch2_readahead(struct readahead_control *);
-
-int bch2_write_begin(struct file *, struct address_space *, loff_t,
-		     unsigned, struct page **, void **);
-int bch2_write_end(struct file *, struct address_space *, loff_t,
-		   unsigned, unsigned, struct page *, void *);
-
-ssize_t bch2_read_iter(struct kiocb *, struct iov_iter *);
-ssize_t bch2_write_iter(struct kiocb *, struct iov_iter *);
 
 int bch2_fsync(struct file *, loff_t, loff_t, int);
 
···
 			     loff_t, loff_t, unsigned);
 
 loff_t bch2_llseek(struct file *, loff_t, int);
-
-vm_fault_t bch2_page_fault(struct vm_fault *);
-vm_fault_t bch2_page_mkwrite(struct vm_fault *);
-void bch2_invalidate_folio(struct folio *, size_t, size_t);
-bool bch2_release_folio(struct folio *, gfp_t);
 
 void bch2_fs_fsio_exit(struct bch_fs *);
 int bch2_fs_fsio_init(struct bch_fs *);

fs/bcachefs/fs.c

···
 #include "fs-common.h"
 #include "fs-io.h"
 #include "fs-ioctl.h"
+#include "fs-io-buffered.h"
+#include "fs-io-direct.h"
+#include "fs-io-pagecache.h"
 #include "fsck.h"
 #include "inode.h"
 #include "io.h"

fs/bcachefs/super.c

···
 #include "error.h"
 #include "fs.h"
 #include "fs-io.h"
+#include "fs-io-buffered.h"
+#include "fs-io-direct.h"
 #include "fsck.h"
 #include "inode.h"
 #include "io.h"
···
 	bch2_fs_counters_exit(c);
 	bch2_fs_snapshots_exit(c);
 	bch2_fs_quota_exit(c);
+	bch2_fs_fs_io_direct_exit(c);
+	bch2_fs_fs_io_buffered_exit(c);
 	bch2_fs_fsio_exit(c);
 	bch2_fs_ec_exit(c);
 	bch2_fs_encryption_exit(c);
···
 	    bch2_fs_encryption_init(c) ?:
 	    bch2_fs_compress_init(c) ?:
 	    bch2_fs_ec_init(c) ?:
-	    bch2_fs_fsio_init(c);
+	    bch2_fs_fsio_init(c) ?:
+	    bch2_fs_fs_io_buffered_init(c);
+	    bch2_fs_fs_io_direct_init(c);
 	if (ret)
 		goto err;