git.sesse.net Git - bcachefs-tools-debian/blob - c_src/libbcachefs/io_read.h

   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
   7 struct 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
  78 struct bch_devs_mask;
  79 struct cache_promote_op;
  80 struct extent_ptr_decoded;
  81
  82 int __bch2_read_indirect_extent(struct btree_trans *, unsigned *,
  83                                 struct bkey_buf *);
  84
  85 static 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
  97 enum 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
 110 int __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
 115 static 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
 124 void __bch2_read(struct bch_fs *, struct bch_read_bio *, struct bvec_iter,
 125                  subvol_inum, struct bch_io_failures *, unsigned flags);
 126
 127 static 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
 144 static 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
 155 void bch2_fs_io_read_exit(struct bch_fs *);
 156 int bch2_fs_io_read_init(struct bch_fs *);
 157
 158 #endif /* _BCACHEFS_IO_READ_H */