bcachefs: Break up io.c

More reorganization, this splits up io.c into
 - io_read.c
 - io_misc.c - fallocate, fpunch, truncate
 - io_write.c

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 215 insertions, 0 deletions

diff --git a/fs/bcachefs/io_misc.c b/fs/bcachefs/io_misc.c
new file mode 100644
index 000000000000..c04e5dacfc8d
--- /dev/null
+++ b/fs/bcachefs/io_misc.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * io_misc.c - fallocate, fpunch, truncate:
+ */
+
+#include "bcachefs.h"
+#include "alloc_foreground.h"
+#include "bkey_buf.h"
+#include "btree_update.h"
+#include "buckets.h"
+#include "clock.h"
+#include "extents.h"
+#include "io_misc.h"
+#include "io_write.h"
+#include "subvolume.h"
+
+/* Overwrites whatever was present with zeroes: */
+int bch2_extent_fallocate(struct btree_trans *trans,
+			  subvol_inum inum,
+			  struct btree_iter *iter,
+			  unsigned sectors,
+			  struct bch_io_opts opts,
+			  s64 *i_sectors_delta,
+			  struct write_point_specifier write_point)
+{
+	struct bch_fs *c = trans->c;
+	struct disk_reservation disk_res = { 0 };
+	struct closure cl;
+	struct open_buckets open_buckets = { 0 };
+	struct bkey_s_c k;
+	struct bkey_buf old, new;
+	unsigned sectors_allocated = 0;
+	bool have_reservation = false;
+	bool unwritten = opts.nocow &&
+	    c->sb.version >= bcachefs_metadata_version_unwritten_extents;
+	int ret;
+
+	bch2_bkey_buf_init(&old);
+	bch2_bkey_buf_init(&new);
+	closure_init_stack(&cl);
+
+	k = bch2_btree_iter_peek_slot(iter);
+	ret = bkey_err(k);
+	if (ret)
+		return ret;
+
+	sectors = min_t(u64, sectors, k.k->p.offset - iter->pos.offset);
+
+	if (!have_reservation) {
+		unsigned new_replicas =
+			max(0, (int) opts.data_replicas -
+			    (int) bch2_bkey_nr_ptrs_fully_allocated(k));
+		/*
+		 * Get a disk reservation before (in the nocow case) calling
+		 * into the allocator:
+		 */
+		ret = bch2_disk_reservation_get(c, &disk_res, sectors, new_replicas, 0);
+		if (unlikely(ret))
+			goto err;
+
+		bch2_bkey_buf_reassemble(&old, c, k);
+	}
+
+	if (have_reservation) {
+		if (!bch2_extents_match(k, bkey_i_to_s_c(old.k)))
+			goto err;
+
+		bch2_key_resize(&new.k->k, sectors);
+	} else if (!unwritten) {
+		struct bkey_i_reservation *reservation;
+
+		bch2_bkey_buf_realloc(&new, c, sizeof(*reservation) / sizeof(u64));
+		reservation = bkey_reservation_init(new.k);
+		reservation->k.p = iter->pos;
+		bch2_key_resize(&reservation->k, sectors);
+		reservation->v.nr_replicas = opts.data_replicas;
+	} else {
+		struct bkey_i_extent *e;
+		struct bch_devs_list devs_have;
+		struct write_point *wp;
+		struct bch_extent_ptr *ptr;
+
+		devs_have.nr = 0;
+
+		bch2_bkey_buf_realloc(&new, c, BKEY_EXTENT_U64s_MAX);
+
+		e = bkey_extent_init(new.k);
+		e->k.p = iter->pos;
+
+		ret = bch2_alloc_sectors_start_trans(trans,
+				opts.foreground_target,
+				false,
+				write_point,
+				&devs_have,
+				opts.data_replicas,
+				opts.data_replicas,
+				BCH_WATERMARK_normal, 0, &cl, &wp);
+		if (bch2_err_matches(ret, BCH_ERR_operation_blocked))
+			ret = -BCH_ERR_transaction_restart_nested;
+		if (ret)
+			goto err;
+
+		sectors = min(sectors, wp->sectors_free);
+		sectors_allocated = sectors;
+
+		bch2_key_resize(&e->k, sectors);
+
+		bch2_open_bucket_get(c, wp, &open_buckets);
+		bch2_alloc_sectors_append_ptrs(c, wp, &e->k_i, sectors, false);
+		bch2_alloc_sectors_done(c, wp);
+
+		extent_for_each_ptr(extent_i_to_s(e), ptr)
+			ptr->unwritten = true;
+	}
+
+	have_reservation = true;
+
+	ret = bch2_extent_update(trans, inum, iter, new.k, &disk_res,
+				 0, i_sectors_delta, true);
+err:
+	if (!ret && sectors_allocated)
+		bch2_increment_clock(c, sectors_allocated, WRITE);
+
+	bch2_open_buckets_put(c, &open_buckets);
+	bch2_disk_reservation_put(c, &disk_res);
+	bch2_bkey_buf_exit(&new, c);
+	bch2_bkey_buf_exit(&old, c);
+
+	if (closure_nr_remaining(&cl) != 1) {
+		bch2_trans_unlock(trans);
+		closure_sync(&cl);
+	}
+
+	return ret;
+}
+
+/*
+ * Returns -BCH_ERR_transacton_restart if we had to drop locks:
+ */
+int bch2_fpunch_at(struct btree_trans *trans, struct btree_iter *iter,
+		   subvol_inum inum, u64 end,
+		   s64 *i_sectors_delta)
+{
+	struct bch_fs *c	= trans->c;
+	unsigned max_sectors	= KEY_SIZE_MAX & (~0 << c->block_bits);
+	struct bpos end_pos = POS(inum.inum, end);
+	struct bkey_s_c k;
+	int ret = 0, ret2 = 0;
+	u32 snapshot;
+
+	while (!ret ||
+	       bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
+		struct disk_reservation disk_res =
+			bch2_disk_reservation_init(c, 0);
+		struct bkey_i delete;
+
+		if (ret)
+			ret2 = ret;
+
+		bch2_trans_begin(trans);
+
+		ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
+		if (ret)
+			continue;
+
+		bch2_btree_iter_set_snapshot(iter, snapshot);
+
+		/*
+		 * peek_upto() doesn't have ideal semantics for extents:
+		 */
+		k = bch2_btree_iter_peek_upto(iter, end_pos);
+		if (!k.k)
+			break;
+
+		ret = bkey_err(k);
+		if (ret)
+			continue;
+
+		bkey_init(&delete.k);
+		delete.k.p = iter->pos;
+
+		/* create the biggest key we can */
+		bch2_key_resize(&delete.k, max_sectors);
+		bch2_cut_back(end_pos, &delete);
+
+		ret = bch2_extent_update(trans, inum, iter, &delete,
+				&disk_res, 0, i_sectors_delta, false);
+		bch2_disk_reservation_put(c, &disk_res);
+	}
+
+	return ret ?: ret2;
+}
+
+int bch2_fpunch(struct bch_fs *c, subvol_inum inum, u64 start, u64 end,
+		s64 *i_sectors_delta)
+{
+	struct btree_trans trans;
+	struct btree_iter iter;
+	int ret;
+
+	bch2_trans_init(&trans, c, BTREE_ITER_MAX, 1024);
+	bch2_trans_iter_init(&trans, &iter, BTREE_ID_extents,
+			     POS(inum.inum, start),
+			     BTREE_ITER_INTENT);
+
+	ret = bch2_fpunch_at(&trans, &iter, inum, end, i_sectors_delta);
+
+	bch2_trans_iter_exit(&trans, &iter);
+	bch2_trans_exit(&trans);
+
+	if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+		ret = 0;
+
+	return ret;
+}