1 files changed, 173 insertions, 228 deletions

diff --git a/fs/bcachefs/fs-io-buffered.c b/fs/bcachefs/fs-io-buffered.c
index 39292e7ef342..66bacdd49f78 100644
--- a/fs/bcachefs/fs-io-buffered.c
+++ b/fs/bcachefs/fs-io-buffered.c
@@ -30,15 +30,8 @@ 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_for_each_folio_all(fi, bio)
+		folio_end_read(fi.folio, bio->bi_status == BLK_STS_OK);
 
 	bio_put(bio);
 }
@@ -117,11 +110,21 @@ static int readpage_bio_extend(struct btree_trans *trans,
 			if (!get_more)
 				break;
 
+			unsigned sectors_remaining = sectors_this_extent - bio_sectors(bio);
+
+			if (sectors_remaining < PAGE_SECTORS << mapping_min_folio_order(iter->mapping))
+				break;
+
+			unsigned order = ilog2(rounddown_pow_of_two(sectors_remaining) / PAGE_SECTORS);
+
+			/* ensure proper alignment */
+			order = min(order, __ffs(folio_offset|BIT(31)));
+
 			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);
+			folio = filemap_alloc_folio(readahead_gfp_mask(iter->mapping), order);
 			if (!folio)
 				break;
 
@@ -156,47 +159,39 @@ static void bchfs_read(struct btree_trans *trans,
 	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 flags = BCH_READ_retry_if_stale|
+		BCH_READ_may_promote;
 	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);
+			     POS(inum.inum, rbio->bio.bi_iter.bi_sector),
+			     BTREE_ITER_slots);
 	while (1) {
 		struct bkey_s_c k;
-		unsigned bytes, sectors, offset_into_extent;
+		unsigned bytes, sectors;
+		s64 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);
+		bch2_trans_begin(trans);
+
+		u32 snapshot;
+		ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
 		if (ret)
-			break;
+			goto err;
+
+		bch2_btree_iter_set_snapshot(trans, &iter, snapshot);
 
-		bch2_btree_iter_set_pos(&iter,
+		bch2_btree_iter_set_pos(trans, &iter,
 				POS(inum.inum, rbio->bio.bi_iter.bi_sector));
 
-		k = bch2_btree_iter_peek_slot(&iter);
+		k = bch2_btree_iter_peek_slot(trans, &iter);
 		ret = bkey_err(k);
 		if (ret)
-			break;
+			goto err;
 
 		offset_into_extent = iter.pos.offset -
 			bkey_start_offset(k.k);
@@ -207,51 +202,65 @@ retry:
 		ret = bch2_read_indirect_extent(trans, &data_btree,
 					&offset_into_extent, &sk);
 		if (ret)
-			break;
+			goto err;
 
 		k = bkey_i_to_s_c(sk.k);
 
-		sectors = min(sectors, k.k->size - offset_into_extent);
+		sectors = min_t(unsigned, 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;
+				goto err;
 		}
 
 		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;
+			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);
+		/*
+		 * Careful there's a landmine here if bch2_read_extent() ever
+		 * starts returning transaction restarts here.
+		 *
+		 * We've changed rbio->bi_iter.bi_size to be "bytes we can read
+		 * from this extent" with the swap call, and we restore it
+		 * below. That restore needs to come before checking for
+		 * errors.
+		 *
+		 * But unlike __bch2_read(), we use the rbio bvec iter, not one
+		 * on the stack, so we can't do the restore right after the
+		 * bch2_read_extent() call: we don't own that iterator anymore
+		 * if BCH_READ_last_fragment is set, since we may have submitted
+		 * that rbio instead of cloning it.
+		 */
 
-		if (flags & BCH_READ_LAST_FRAGMENT)
+		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)
+err:
+		if (ret &&
+		    !bch2_err_matches(ret, BCH_ERR_transaction_restart))
 			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);
+		struct printbuf buf = PRINTBUF;
+		lockrestart_do(trans,
+			bch2_inum_offset_err_msg_trans(trans, &buf, inum, iter.pos.offset << 9));
+		prt_printf(&buf, "read error %i from btree lookup", ret);
+		bch_err_ratelimited(c, "%s", buf.buf);
+		printbuf_exit(&buf);
+
 		rbio->bio.bi_status = BLK_STS_IOERR;
 		bio_endio(&rbio->bio);
 	}
@@ -264,9 +273,9 @@ 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 = bch2_trans_get(c);
 	struct folio *folio;
 	struct readpages_iter readpages_iter;
+	struct blk_plug plug;
 
 	bch2_inode_opts_get(&opts, c, &inode->ei_inode);
 
@@ -274,8 +283,19 @@ void bch2_readahead(struct readahead_control *ractl)
 	if (ret)
 		return;
 
+	/*
+	 * Besides being a general performance optimization, plugging helps with
+	 * avoiding btree transaction srcu warnings - submitting a bio can
+	 * block, and we don't want todo that with the transaction locked.
+	 *
+	 * However, plugged bios are submitted when we schedule; we ideally
+	 * would have our own scheduler hook to call unlock_long() before
+	 * scheduling.
+	 */
+	blk_start_plug(&plug);
 	bch2_pagecache_add_get(inode);
 
+	struct btree_trans *trans = bch2_trans_get(c);
 	while ((folio = readpage_iter_peek(&readpages_iter))) {
 		unsigned n = min_t(unsigned,
 				   readpages_iter.folios.nr -
@@ -284,22 +304,23 @@ void bch2_readahead(struct readahead_control *ractl)
 		struct bch_read_bio *rbio =
 			rbio_init(bio_alloc_bioset(NULL, n, REQ_OP_READ,
 						   GFP_KERNEL, &c->bio_read),
-				  opts);
+				  c,
+				  opts,
+				  bch2_readpages_end_io);
 
 		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_trans_put(trans);
 
 	bch2_pagecache_add_put(inode);
-
-	bch2_trans_put(trans);
+	blk_finish_plug(&plug);
 	darray_exit(&readpages_iter.folios);
 }
 
@@ -314,24 +335,30 @@ int bch2_read_single_folio(struct folio *folio, struct address_space *mapping)
 	struct bch_fs *c = inode->v.i_sb->s_fs_info;
 	struct bch_read_bio *rbio;
 	struct bch_io_opts opts;
+	struct blk_plug plug;
 	int ret;
 	DECLARE_COMPLETION_ONSTACK(done);
 
+	BUG_ON(folio_test_uptodate(folio));
+	BUG_ON(folio_test_dirty(folio));
+
 	if (!bch2_folio_create(folio, GFP_KERNEL))
 		return -ENOMEM;
 
 	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);
+			 c,
+			 opts,
+			 bch2_read_single_folio_end_io);
 	rbio->bio.bi_private = &done;
-	rbio->bio.bi_end_io = bch2_read_single_folio_end_io;
-
 	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));
 
+	blk_start_plug(&plug);
 	bch2_trans_run(c, (bchfs_read(trans, rbio, inode_inum(inode), NULL), 0));
+	blk_finish_plug(&plug);
 	wait_for_completion(&done);
 
 	ret = blk_status_to_errno(rbio->bio.bi_status);
@@ -367,17 +394,9 @@ struct bch_writepage_state {
 	struct bch_io_opts	opts;
 	struct bch_folio_sector	*tmp;
 	unsigned		tmp_sectors;
+	struct blk_plug		plug;
 };
 
-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;
-}
-
 /*
  * Determine when a writepage io is full. We have to limit writepage bios to a
  * single page per bvec (i.e. 1MB with 4k pages) because that is the limit to
@@ -408,7 +427,6 @@ static void bch2_writepage_io_done(struct bch_write_op *op)
 		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);
@@ -419,7 +437,7 @@ static void bch2_writepage_io_done(struct bch_write_op *op)
 		}
 	}
 
-	if (io->op.flags & BCH_WRITE_WROTE_DATA_INLINE) {
+	if (io->op.flags & BCH_WRITE_wrote_data_inline) {
 		bio_for_each_folio_all(fi, bio) {
 			struct bch_folio *s;
 
@@ -445,8 +463,8 @@ static void bch2_writepage_io_done(struct bch_write_op *op)
 	 */
 
 	/*
-	 * PageWriteback is effectively our ref on the inode - fixup i_blocks
-	 * before calling end_page_writeback:
+	 * The writeback flag is effectively our ref on the inode -
+	 * fixup i_blocks before calling folio_end_writeback:
 	 */
 	bch2_i_sectors_acct(c, io->inode, NULL, io->op.i_sectors_delta);
 
@@ -494,7 +512,7 @@ static void bch2_writepage_io_alloc(struct bch_fs *c,
 	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->subvol		= inode->ei_inum.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;
@@ -542,7 +560,7 @@ do_io:
 
 	if (f_sectors > w->tmp_sectors) {
 		kfree(w->tmp);
-		w->tmp = kcalloc(f_sectors, sizeof(struct bch_folio_sector), __GFP_NOFAIL);
+		w->tmp = kcalloc(f_sectors, sizeof(struct bch_folio_sector), GFP_NOFS|__GFP_NOFAIL);
 		w->tmp_sectors = f_sectors;
 	}
 
@@ -624,15 +642,6 @@ do_io:
 		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;
@@ -649,17 +658,17 @@ do_io:
 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;
+	struct bch_writepage_state *w = kzalloc(sizeof(*w), GFP_NOFS|__GFP_NOFAIL);
 
-	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);
+	bch2_inode_opts_get(&w->opts, c, &to_bch_ei(mapping->host)->ei_inode);
+
+	blk_start_plug(&w->plug);
+	int ret = write_cache_pages(mapping, wbc, __bch2_writepage, w);
+	if (w->io)
+		bch2_writepage_do_io(w);
+	blk_finish_plug(&w->plug);
+	kfree(w->tmp);
+	kfree(w);
 	return bch2_err_class(ret);
 }
 
@@ -667,7 +676,7 @@ int bch2_writepages(struct address_space *mapping, struct writeback_control *wbc
 
 int bch2_write_begin(struct file *file, struct address_space *mapping,
 		     loff_t pos, unsigned len,
-		     struct page **pagep, void **fsdata)
+		     struct folio **foliop, void **fsdata)
 {
 	struct bch_inode_info *inode = to_bch_ei(mapping->host);
 	struct bch_fs *c = inode->v.i_sb->s_fs_info;
@@ -686,9 +695,9 @@ int bch2_write_begin(struct file *file, struct address_space *mapping,
 	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))
+				    FGP_WRITEBEGIN | fgf_set_order(len),
+				    mapping_gfp_mask(mapping));
+	if (IS_ERR(folio))
 		goto err_unlock;
 
 	offset = pos - folio_pos(folio);
@@ -736,12 +745,11 @@ out:
 		goto err;
 	}
 
-	*pagep = &folio->page;
+	*foliop = folio;
 	return 0;
 err:
 	folio_unlock(folio);
 	folio_put(folio);
-	*pagep = NULL;
 err_unlock:
 	bch2_pagecache_add_put(inode);
 	kfree(res);
@@ -751,12 +759,11 @@ err_unlock:
 
 int bch2_write_end(struct file *file, struct address_space *mapping,
 		   loff_t pos, unsigned len, unsigned copied,
-		   struct page *page, void *fsdata)
+		   struct folio *folio, 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);
@@ -810,8 +817,7 @@ static noinline void folios_trunc(folios *fs, struct folio **fi)
 static int __bch2_buffered_write(struct bch_inode_info *inode,
 				 struct address_space *mapping,
 				 struct iov_iter *iter,
-				 loff_t pos, unsigned len,
-				 bool inode_locked)
+				 loff_t pos, unsigned len)
 {
 	struct bch_fs *c = inode->v.i_sb->s_fs_info;
 	struct bch2_folio_reservation res;
@@ -828,23 +834,13 @@ static int __bch2_buffered_write(struct bch_inode_info *inode,
 	darray_init(&fs);
 
 	ret = bch2_filemap_get_contig_folios_d(mapping, pos, end,
-				   FGP_LOCK|FGP_WRITE|FGP_STABLE|FGP_CREAT,
-				   mapping_gfp_mask(mapping),
-				   &fs);
+					       FGP_WRITEBEGIN | fgf_set_order(len),
+					       mapping_gfp_mask(mapping), &fs);
 	if (ret)
 		goto out;
 
 	BUG_ON(!fs.nr);
 
-	/*
-	 * If we're not using the inode lock, we need to lock all the folios for
-	 * atomiticity of writes vs. other writes:
-	 */
-	if (!inode_locked && folio_end_pos(darray_last(fs)) < end) {
-		ret = -BCH_ERR_need_inode_lock;
-		goto out;
-	}
-
 	f = darray_first(fs);
 	if (pos != folio_pos(f) && !folio_test_uptodate(f)) {
 		ret = bch2_read_single_folio(f, mapping);
@@ -872,24 +868,32 @@ static int __bch2_buffered_write(struct bch_inode_info *inode,
 	f_pos = pos;
 	f_offset = pos - folio_pos(darray_first(fs));
 	darray_for_each(fs, fi) {
+		ssize_t f_reserved;
+
 		f = *fi;
 		f_len = min(end, folio_end_pos(f)) - f_pos;
+		f_reserved = bch2_folio_reservation_get_partial(c, inode, f, &res, f_offset, f_len);
+
+		if (unlikely(f_reserved != f_len)) {
+			if (f_reserved < 0) {
+				if (f == darray_first(fs)) {
+					ret = f_reserved;
+					goto out;
+				}
+
+				folios_trunc(&fs, fi);
+				end = min(end, folio_end_pos(darray_last(fs)));
+			} else {
+				if (!folio_test_uptodate(f)) {
+					ret = bch2_read_single_folio(f, mapping);
+					if (ret)
+						goto out;
+				}
+
+				folios_trunc(&fs, fi + 1);
+				end = f_pos + f_reserved;
+			}
 
-		/*
-		 * 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(&fs, fi);
-			if (!fs.nr)
-				goto out;
-
-			end = min(end, folio_end_pos(darray_last(fs)));
 			break;
 		}
 
@@ -906,7 +910,7 @@ static int __bch2_buffered_write(struct bch_inode_info *inode,
 	darray_for_each(fs, fi) {
 		f = *fi;
 		f_len = min(end, folio_end_pos(f)) - f_pos;
-		f_copied = copy_page_from_iter_atomic(&f->page, f_offset, f_len, iter);
+		f_copied = copy_folio_from_iter_atomic(f, f_offset, f_len, iter);
 		if (!f_copied) {
 			folios_trunc(&fs, fi);
 			break;
@@ -939,10 +943,8 @@ static int __bch2_buffered_write(struct bch_inode_info *inode,
 	end = pos + copied;
 
 	spin_lock(&inode->v.i_lock);
-	if (end > inode->v.i_size) {
-		BUG_ON(!inode_locked);
+	if (end > inode->v.i_size)
 		i_size_write(&inode->v, end);
-	}
 	spin_unlock(&inode->v.i_lock);
 
 	f_pos = pos;
@@ -986,68 +988,12 @@ 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;
-	bool inode_locked = false;
-	ssize_t written = 0, written2 = 0, ret = 0;
-
-	/*
-	 * We don't take the inode lock unless i_size will be changing. Folio
-	 * locks provide exclusion with other writes, and the pagecache add lock
-	 * provides exclusion with truncate and hole punching.
-	 *
-	 * There is one nasty corner case where atomicity would be broken
-	 * without great care: when copying data from userspace to the page
-	 * cache, we do that with faults disable - a page fault would recurse
-	 * back into the filesystem, taking filesystem locks again, and
-	 * deadlock; so it's done with faults disabled, and we fault in the user
-	 * buffer when we aren't holding locks.
-	 *
-	 * If we do part of the write, but we then race and in the userspace
-	 * buffer have been evicted and are no longer resident, then we have to
-	 * drop our folio locks to re-fault them in, breaking write atomicity.
-	 *
-	 * To fix this, we restart the write from the start, if we weren't
-	 * holding the inode lock.
-	 *
-	 * There is another wrinkle after that; if we restart the write from the
-	 * start, and then get an unrecoverable error, we _cannot_ claim to
-	 * userspace that we did not write data we actually did - so we must
-	 * track (written2) the most we ever wrote.
-	 */
-
-	if ((iocb->ki_flags & IOCB_APPEND) ||
-	    (iocb->ki_pos + iov_iter_count(iter) > i_size_read(&inode->v))) {
-		inode_lock(&inode->v);
-		inode_locked = true;
-	}
-
-	ret = generic_write_checks(iocb, iter);
-	if (ret <= 0)
-		goto unlock;
-
-	ret = file_remove_privs_flags(file, !inode_locked ? IOCB_NOWAIT : 0);
-	if (ret) {
-		if (!inode_locked) {
-			inode_lock(&inode->v);
-			inode_locked = true;
-			ret = file_remove_privs_flags(file, 0);
-		}
-		if (ret)
-			goto unlock;
-	}
-
-	ret = file_update_time(file);
-	if (ret)
-		goto unlock;
-
-	pos = iocb->ki_pos;
+	loff_t pos = iocb->ki_pos;
+	ssize_t written = 0;
+	int ret = 0;
 
 	bch2_pagecache_add_get(inode);
 
-	if (!inode_locked &&
-	    (iocb->ki_pos + iov_iter_count(iter) > i_size_read(&inode->v)))
-		goto get_inode_lock;
-
 	do {
 		unsigned offset = pos & (PAGE_SIZE - 1);
 		unsigned bytes = iov_iter_count(iter);
@@ -1072,17 +1018,12 @@ again:
 			}
 		}
 
-		if (unlikely(bytes != iov_iter_count(iter) && !inode_locked))
-			goto get_inode_lock;
-
 		if (unlikely(fatal_signal_pending(current))) {
 			ret = -EINTR;
 			break;
 		}
 
-		ret = __bch2_buffered_write(inode, mapping, iter, pos, bytes, inode_locked);
-		if (ret == -BCH_ERR_need_inode_lock)
-			goto get_inode_lock;
+		ret = __bch2_buffered_write(inode, mapping, iter, pos, bytes);
 		if (unlikely(ret < 0))
 			break;
 
@@ -1103,46 +1044,50 @@ again:
 		}
 		pos += ret;
 		written += ret;
-		written2 = max(written, written2);
-
-		if (ret != bytes && !inode_locked)
-			goto get_inode_lock;
 		ret = 0;
 
 		balance_dirty_pages_ratelimited(mapping);
-
-		if (0) {
-get_inode_lock:
-			bch2_pagecache_add_put(inode);
-			inode_lock(&inode->v);
-			inode_locked = true;
-			bch2_pagecache_add_get(inode);
-
-			iov_iter_revert(iter, written);
-			pos -= written;
-			written = 0;
-			ret = 0;
-		}
 	} while (iov_iter_count(iter));
-	bch2_pagecache_add_put(inode);
-unlock:
-	if (inode_locked)
-		inode_unlock(&inode->v);
 
-	iocb->ki_pos += written;
+	bch2_pagecache_add_put(inode);
 
-	ret = max(written, written2) ?: ret;
-	if (ret > 0)
-		ret = generic_write_sync(iocb, ret);
-	return ret;
+	return written ? written : ret;
 }
 
-ssize_t bch2_write_iter(struct kiocb *iocb, struct iov_iter *iter)
+ssize_t bch2_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
-	ssize_t ret = iocb->ki_flags & IOCB_DIRECT
-		? bch2_direct_write(iocb, iter)
-		: bch2_buffered_write(iocb, iter);
+	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);
 }