1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 2012 Fusion-io All rights reserved.
4 * Copyright (C) 2012 Intel Corp. All rights reserved.
5 */
6
7 #ifndef BTRFS_RAID56_H
8 #define BTRFS_RAID56_H
9
10 #include <linux/workqueue.h>
11 #include "volumes.h"
12
13 enum btrfs_rbio_ops {
14 BTRFS_RBIO_WRITE,
15 BTRFS_RBIO_READ_REBUILD,
16 BTRFS_RBIO_PARITY_SCRUB,
17 };
18
19 struct btrfs_raid_bio {
20 struct btrfs_io_context *bioc;
21
22 /*
23 * While we're doing RMW on a stripe we put it into a hash table so we
24 * can lock the stripe and merge more rbios into it.
25 */
26 struct list_head hash_list;
27
28 /* LRU list for the stripe cache */
29 struct list_head stripe_cache;
30
31 /* For scheduling work in the helper threads */
32 struct work_struct work;
33
34 /*
35 * bio_list and bio_list_lock are used to add more bios into the stripe
36 * in hopes of avoiding the full RMW
37 */
38 struct bio_list bio_list;
39 spinlock_t bio_list_lock;
40
41 /*
42 * Also protected by the bio_list_lock, the plug list is used by the
43 * plugging code to collect partial bios while plugged. The stripe
44 * locking code also uses it to hand off the stripe lock to the next
45 * pending IO.
46 */
47 struct list_head plug_list;
48
49 /* Flags that tell us if it is safe to merge with this bio. */
50 unsigned long flags;
51
52 /*
53 * Set if we're doing a parity rebuild for a read from higher up, which
54 * is handled differently from a parity rebuild as part of RMW.
55 */
56 enum btrfs_rbio_ops operation;
57
58 /* How many pages there are for the full stripe including P/Q */
59 u16 nr_pages;
60
61 /* How many sectors there are for the full stripe including P/Q */
62 u16 nr_sectors;
63
64 /* Number of data stripes (no p/q) */
65 u8 nr_data;
66
67 /* Number of all stripes (including P/Q) */
68 u8 real_stripes;
69
70 /* How many pages there are for each stripe */
71 u8 stripe_npages;
72
73 /* How many sectors there are for each stripe */
74 u8 stripe_nsectors;
75
76 /* Stripe number that we're scrubbing */
77 u8 scrubp;
78
79 /*
80 * Size of all the bios in the bio_list. This helps us decide if the
81 * rbio maps to a full stripe or not.
82 */
83 int bio_list_bytes;
84
85 refcount_t refs;
86
87 atomic_t stripes_pending;
88
89 wait_queue_head_t io_wait;
90
91 /* Bitmap to record which horizontal stripe has data */
92 unsigned long dbitmap;
93
94 /* Allocated with stripe_nsectors-many bits for finish_*() calls */
95 unsigned long finish_pbitmap;
96
97 /*
98 * These are two arrays of pointers. We allocate the rbio big enough
99 * to hold them both and setup their locations when the rbio is
100 * allocated.
101 */
102
103 /*
104 * Pointers to pages that we allocated for reading/writing stripes
105 * directly from the disk (including P/Q).
106 */
107 struct page **stripe_pages;
108
109 /* Pointers to the sectors in the bio_list, for faster lookup */
110 struct sector_ptr *bio_sectors;
111
112 /*
113 * For subpage support, we need to map each sector to above
114 * stripe_pages.
115 */
116 struct sector_ptr *stripe_sectors;
117
118 /* Allocated with real_stripes-many pointers for finish_*() calls */
119 void **finish_pointers;
120
121 /*
122 * The bitmap recording where IO errors happened.
123 * Each bit is corresponding to one sector in either bio_sectors[] or
124 * stripe_sectors[] array.
125 *
126 * The reason we don't use another bit in sector_ptr is, we have two
127 * arrays of sectors, and a lot of IO can use sectors in both arrays.
128 * Thus making it much harder to iterate.
129 */
130 unsigned long *error_bitmap;
131
132 /*
133 * Checksum buffer if the rbio is for data. The buffer should cover
134 * all data sectors (excluding P/Q sectors).
135 */
136 u8 *csum_buf;
137
138 /*
139 * Each bit represents if the corresponding sector has data csum found.
140 * Should only cover data sectors (excluding P/Q sectors).
141 */
142 unsigned long *csum_bitmap;
143 };
144
145 /*
146 * For trace event usage only. Records useful debug info for each bio submitted
147 * by RAID56 to each physical device.
148 *
149 * No matter signed or not, (-1) is always the one indicating we can not grab
150 * the proper stripe number.
151 */
152 struct raid56_bio_trace_info {
153 u64 devid;
154
155 /* The offset inside the stripe. (<= STRIPE_LEN) */
156 u32 offset;
157
158 /*
159 * Stripe number.
160 * 0 is the first data stripe, and nr_data for P stripe,
161 * nr_data + 1 for Q stripe.
162 * >= real_stripes for
163 */
164 u8 stripe_nr;
165 };
166
nr_data_stripes(const struct map_lookup * map)167 static inline int nr_data_stripes(const struct map_lookup *map)
168 {
169 return map->num_stripes - btrfs_nr_parity_stripes(map->type);
170 }
171
nr_bioc_data_stripes(const struct btrfs_io_context * bioc)172 static inline int nr_bioc_data_stripes(const struct btrfs_io_context *bioc)
173 {
174 return bioc->num_stripes - btrfs_nr_parity_stripes(bioc->map_type);
175 }
176
177 #define RAID5_P_STRIPE ((u64)-2)
178 #define RAID6_Q_STRIPE ((u64)-1)
179
180 #define is_parity_stripe(x) (((x) == RAID5_P_STRIPE) || \
181 ((x) == RAID6_Q_STRIPE))
182
183 struct btrfs_device;
184
185 void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
186 int mirror_num);
187 void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc);
188
189 struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio,
190 struct btrfs_io_context *bioc,
191 struct btrfs_device *scrub_dev,
192 unsigned long *dbitmap, int stripe_nsectors);
193 void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio);
194
195 void raid56_parity_cache_data_pages(struct btrfs_raid_bio *rbio,
196 struct page **data_pages, u64 data_logical);
197
198 int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info);
199 void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info);
200
201 #endif
202