xref: /linux/fs/btrfs/bio.h (revision 0da908c291070d89482f6211dbe81d4d43c3f7cb)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Copyright (C) 2007 Oracle.  All rights reserved.
4  * Copyright (C) 2022 Christoph Hellwig.
5  */
6 
7 #ifndef BTRFS_BIO_H
8 #define BTRFS_BIO_H
9 
10 #include <linux/bio.h>
11 #include <linux/workqueue.h>
12 #include "tree-checker.h"
13 
14 struct btrfs_bio;
15 struct btrfs_fs_info;
16 
17 #define BTRFS_BIO_INLINE_CSUM_SIZE	64
18 
19 /*
20  * Maximum number of sectors for a single bio to limit the size of the
21  * checksum array.  This matches the number of bio_vecs per bio and thus the
22  * I/O size for buffered I/O.
23  */
24 #define BTRFS_MAX_BIO_SECTORS		(256)
25 
26 typedef void (*btrfs_bio_end_io_t)(struct btrfs_bio *bbio);
27 
28 /*
29  * Additional info to pass along bio.
30  *
31  * Mostly for btrfs specific features like csum and mirror_num.
32  */
33 struct btrfs_bio {
34 	unsigned int mirror_num:7;
35 
36 	/*
37 	 * Extra indicator for metadata bios.
38 	 * For some btrfs bios they use pages without a mapping, thus
39 	 * we can not rely on page->mapping->host to determine if
40 	 * it's a metadata bio.
41 	 */
42 	unsigned int is_metadata:1;
43 	struct bvec_iter iter;
44 
45 	/* for direct I/O */
46 	u64 file_offset;
47 
48 	/* @device is for stripe IO submission. */
49 	struct btrfs_device *device;
50 	union {
51 		/* For data checksum verification. */
52 		struct {
53 			u8 *csum;
54 			u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE];
55 		};
56 
57 		/* For metadata parentness verification. */
58 		struct btrfs_tree_parent_check parent_check;
59 	};
60 
61 	/* End I/O information supplied to btrfs_bio_alloc */
62 	btrfs_bio_end_io_t end_io;
63 	void *private;
64 
65 	/* For read end I/O handling */
66 	struct work_struct end_io_work;
67 
68 	/*
69 	 * This member must come last, bio_alloc_bioset will allocate enough
70 	 * bytes for entire btrfs_bio but relies on bio being last.
71 	 */
72 	struct bio bio;
73 };
74 
75 static inline struct btrfs_bio *btrfs_bio(struct bio *bio)
76 {
77 	return container_of(bio, struct btrfs_bio, bio);
78 }
79 
80 int __init btrfs_bioset_init(void);
81 void __cold btrfs_bioset_exit(void);
82 
83 struct bio *btrfs_bio_alloc(unsigned int nr_vecs, blk_opf_t opf,
84 			    btrfs_bio_end_io_t end_io, void *private);
85 struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size,
86 				    btrfs_bio_end_io_t end_io, void *private);
87 
88 
89 static inline void btrfs_bio_end_io(struct btrfs_bio *bbio, blk_status_t status)
90 {
91 	bbio->bio.bi_status = status;
92 	bbio->end_io(bbio);
93 }
94 
95 static inline void btrfs_bio_free_csum(struct btrfs_bio *bbio)
96 {
97 	if (bbio->is_metadata)
98 		return;
99 	if (bbio->csum != bbio->csum_inline) {
100 		kfree(bbio->csum);
101 		bbio->csum = NULL;
102 	}
103 }
104 
105 /*
106  * Iterate through a btrfs_bio (@bbio) on a per-sector basis.
107  *
108  * bvl        - struct bio_vec
109  * bbio       - struct btrfs_bio
110  * iters      - struct bvec_iter
111  * bio_offset - unsigned int
112  */
113 #define btrfs_bio_for_each_sector(fs_info, bvl, bbio, iter, bio_offset)	\
114 	for ((iter) = (bbio)->iter, (bio_offset) = 0;			\
115 	     (iter).bi_size &&					\
116 	     (((bvl) = bio_iter_iovec((&(bbio)->bio), (iter))), 1);	\
117 	     (bio_offset) += fs_info->sectorsize,			\
118 	     bio_advance_iter_single(&(bbio)->bio, &(iter),		\
119 	     (fs_info)->sectorsize))
120 
121 void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
122 		      int mirror_num);
123 int btrfs_repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
124 			    u64 length, u64 logical, struct page *page,
125 			    unsigned int pg_offset, int mirror_num);
126 
127 #endif
128