1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _BCACHEFS_IO_READ_H
  3#define _BCACHEFS_IO_READ_H
  4
  5#include "bkey_buf.h"
  6
  7struct bch_read_bio {
  8	struct bch_fs		*c;
  9	u64			start_time;
 10	u64			submit_time;
 11
 12	/*
 13	 * Reads will often have to be split, and if the extent being read from
 14	 * was checksummed or compressed we'll also have to allocate bounce
 15	 * buffers and copy the data back into the original bio.
 16	 *
 17	 * If we didn't have to split, we have to save and restore the original
 18	 * bi_end_io - @split below indicates which:
 19	 */
 20	union {
 21	struct bch_read_bio	*parent;
 22	bio_end_io_t		*end_io;
 23	};
 24
 25	/*
 26	 * Saved copy of bio->bi_iter, from submission time - allows us to
 27	 * resubmit on IO error, and also to copy data back to the original bio
 28	 * when we're bouncing:
 29	 */
 30	struct bvec_iter	bvec_iter;
 31
 32	unsigned		offset_into_extent;
 33
 34	u16			flags;
 35	union {
 36	struct {
 37	u16			bounce:1,
 38				split:1,
 39				kmalloc:1,
 40				have_ioref:1,
 41				narrow_crcs:1,
 42				hole:1,
 43				retry:2,
 44				context:2;
 45	};
 46	u16			_state;
 47	};
 48
 49	struct bch_devs_list	devs_have;
 50
 51	struct extent_ptr_decoded pick;
 52
 53	/*
 54	 * pos we read from - different from data_pos for indirect extents:
 55	 */
 56	u32			subvol;
 57	struct bpos		read_pos;
 58
 59	/*
 60	 * start pos of data we read (may not be pos of data we want) - for
 61	 * promote, narrow extents paths:
 62	 */
 63	enum btree_id		data_btree;
 64	struct bpos		data_pos;
 65	struct bversion		version;
 66
 67	struct promote_op	*promote;
 68
 69	struct bch_io_opts	opts;
 70
 71	struct work_struct	work;
 72
 73	struct bio		bio;
 74};
 75
 76#define to_rbio(_bio)		container_of((_bio), struct bch_read_bio, bio)
 77
 78struct bch_devs_mask;
 79struct cache_promote_op;
 80struct extent_ptr_decoded;
 81
 82int __bch2_read_indirect_extent(struct btree_trans *, unsigned *,
 83				struct bkey_buf *);
 84
 85static inline int bch2_read_indirect_extent(struct btree_trans *trans,
 86					    enum btree_id *data_btree,
 87					    unsigned *offset_into_extent,
 88					    struct bkey_buf *k)
 89{
 90	if (k->k->k.type != KEY_TYPE_reflink_p)
 91		return 0;
 92
 93	*data_btree = BTREE_ID_reflink;
 94	return __bch2_read_indirect_extent(trans, offset_into_extent, k);
 95}
 96
 97enum bch_read_flags {
 98	BCH_READ_RETRY_IF_STALE		= 1 << 0,
 99	BCH_READ_MAY_PROMOTE		= 1 << 1,
100	BCH_READ_USER_MAPPED		= 1 << 2,
101	BCH_READ_NODECODE		= 1 << 3,
102	BCH_READ_LAST_FRAGMENT		= 1 << 4,
103
104	/* internal: */
105	BCH_READ_MUST_BOUNCE		= 1 << 5,
106	BCH_READ_MUST_CLONE		= 1 << 6,
107	BCH_READ_IN_RETRY		= 1 << 7,
108};
109
110int __bch2_read_extent(struct btree_trans *, struct bch_read_bio *,
111		       struct bvec_iter, struct bpos, enum btree_id,
112		       struct bkey_s_c, unsigned,
113		       struct bch_io_failures *, unsigned);
114
115static inline void bch2_read_extent(struct btree_trans *trans,
116			struct bch_read_bio *rbio, struct bpos read_pos,
117			enum btree_id data_btree, struct bkey_s_c k,
118			unsigned offset_into_extent, unsigned flags)
119{
120	__bch2_read_extent(trans, rbio, rbio->bio.bi_iter, read_pos,
121			   data_btree, k, offset_into_extent, NULL, flags);
122}
123
124void __bch2_read(struct bch_fs *, struct bch_read_bio *, struct bvec_iter,
125		 subvol_inum, struct bch_io_failures *, unsigned flags);
126
127static inline void bch2_read(struct bch_fs *c, struct bch_read_bio *rbio,
128			     subvol_inum inum)
129{
130	struct bch_io_failures failed = { .nr = 0 };
131
132	BUG_ON(rbio->_state);
133
134	rbio->c = c;
135	rbio->start_time = local_clock();
136	rbio->subvol = inum.subvol;
137
138	__bch2_read(c, rbio, rbio->bio.bi_iter, inum, &failed,
139		    BCH_READ_RETRY_IF_STALE|
140		    BCH_READ_MAY_PROMOTE|
141		    BCH_READ_USER_MAPPED);
142}
143
144static inline struct bch_read_bio *rbio_init(struct bio *bio,
145					     struct bch_io_opts opts)
146{
147	struct bch_read_bio *rbio = to_rbio(bio);
148
149	rbio->_state	= 0;
150	rbio->promote	= NULL;
151	rbio->opts	= opts;
152	return rbio;
153}
154
155void bch2_fs_io_read_exit(struct bch_fs *);
156int bch2_fs_io_read_init(struct bch_fs *);
157
158#endif /* _BCACHEFS_IO_READ_H */