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/types.h>
11#include <linux/list.h>
12#include <linux/spinlock.h>
13#include <linux/bio.h>
14#include <linux/refcount.h>
15#include <linux/workqueue.h>
16#include "volumes.h"
17
18struct page;
19struct sector_ptr;
20struct btrfs_fs_info;
21
22enum btrfs_rbio_ops {
23	BTRFS_RBIO_WRITE,
24	BTRFS_RBIO_READ_REBUILD,
25	BTRFS_RBIO_PARITY_SCRUB,
26};
27
28struct btrfs_raid_bio {
29	struct btrfs_io_context *bioc;
30
31	/*
32	 * While we're doing RMW on a stripe we put it into a hash table so we
33	 * can lock the stripe and merge more rbios into it.
34	 */
35	struct list_head hash_list;
36
37	/* LRU list for the stripe cache */
38	struct list_head stripe_cache;
39
40	/* For scheduling work in the helper threads */
41	struct work_struct work;
42
43	/*
44	 * bio_list and bio_list_lock are used to add more bios into the stripe
45	 * in hopes of avoiding the full RMW
46	 */
47	struct bio_list bio_list;
48	spinlock_t bio_list_lock;
49
50	/*
51	 * Also protected by the bio_list_lock, the plug list is used by the
52	 * plugging code to collect partial bios while plugged.  The stripe
53	 * locking code also uses it to hand off the stripe lock to the next
54	 * pending IO.
55	 */
56	struct list_head plug_list;
57
58	/* Flags that tell us if it is safe to merge with this bio. */
59	unsigned long flags;
60
61	/*
62	 * Set if we're doing a parity rebuild for a read from higher up, which
63	 * is handled differently from a parity rebuild as part of RMW.
64	 */
65	enum btrfs_rbio_ops operation;
66
67	/* How many pages there are for the full stripe including P/Q */
68	u16 nr_pages;
69
70	/* How many sectors there are for the full stripe including P/Q */
71	u16 nr_sectors;
72
73	/* Number of data stripes (no p/q) */
74	u8 nr_data;
75
76	/* Number of all stripes (including P/Q) */
77	u8 real_stripes;
78
79	/* How many pages there are for each stripe */
80	u8 stripe_npages;
81
82	/* How many sectors there are for each stripe */
83	u8 stripe_nsectors;
84
85	/* Stripe number that we're scrubbing  */
86	u8 scrubp;
87
88	/*
89	 * Size of all the bios in the bio_list.  This helps us decide if the
90	 * rbio maps to a full stripe or not.
91	 */
92	int bio_list_bytes;
93
94	refcount_t refs;
95
96	atomic_t stripes_pending;
97
98	wait_queue_head_t io_wait;
99
100	/* Bitmap to record which horizontal stripe has data */
101	unsigned long dbitmap;
102
103	/* Allocated with stripe_nsectors-many bits for finish_*() calls */
104	unsigned long finish_pbitmap;
105
106	/*
107	 * These are two arrays of pointers.  We allocate the rbio big enough
108	 * to hold them both and setup their locations when the rbio is
109	 * allocated.
110	 */
111
112	/*
113	 * Pointers to pages that we allocated for reading/writing stripes
114	 * directly from the disk (including P/Q).
115	 */
116	struct page **stripe_pages;
117
118	/* Pointers to the sectors in the bio_list, for faster lookup */
119	struct sector_ptr *bio_sectors;
120
121	/*
122	 * For subpage support, we need to map each sector to above
123	 * stripe_pages.
124	 */
125	struct sector_ptr *stripe_sectors;
126
127	/* Allocated with real_stripes-many pointers for finish_*() calls */
128	void **finish_pointers;
129
130	/*
131	 * The bitmap recording where IO errors happened.
132	 * Each bit is corresponding to one sector in either bio_sectors[] or
133	 * stripe_sectors[] array.
134	 *
135	 * The reason we don't use another bit in sector_ptr is, we have two
136	 * arrays of sectors, and a lot of IO can use sectors in both arrays.
137	 * Thus making it much harder to iterate.
138	 */
139	unsigned long *error_bitmap;
140
141	/*
142	 * Checksum buffer if the rbio is for data.  The buffer should cover
143	 * all data sectors (excluding P/Q sectors).
144	 */
145	u8 *csum_buf;
146
147	/*
148	 * Each bit represents if the corresponding sector has data csum found.
149	 * Should only cover data sectors (excluding P/Q sectors).
150	 */
151	unsigned long *csum_bitmap;
152};
153
154/*
155 * For trace event usage only. Records useful debug info for each bio submitted
156 * by RAID56 to each physical device.
157 *
158 * No matter signed or not, (-1) is always the one indicating we can not grab
159 * the proper stripe number.
160 */
161struct raid56_bio_trace_info {
162	u64 devid;
163
164	/* The offset inside the stripe. (<= STRIPE_LEN) */
165	u32 offset;
166
167	/*
168	 * Stripe number.
169	 * 0 is the first data stripe, and nr_data for P stripe,
170	 * nr_data + 1 for Q stripe.
171	 * >= real_stripes for
172	 */
173	u8 stripe_nr;
174};
175
176static inline int nr_data_stripes(const struct btrfs_chunk_map *map)
177{
178	return map->num_stripes - btrfs_nr_parity_stripes(map->type);
179}
180
181static inline int nr_bioc_data_stripes(const struct btrfs_io_context *bioc)
182{
183	return bioc->num_stripes - btrfs_nr_parity_stripes(bioc->map_type);
184}
185
186#define RAID5_P_STRIPE ((u64)-2)
187#define RAID6_Q_STRIPE ((u64)-1)
188
189#define is_parity_stripe(x) (((x) == RAID5_P_STRIPE) ||		\
190			     ((x) == RAID6_Q_STRIPE))
191
192struct btrfs_device;
193
194void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
195			   int mirror_num);
196void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc);
197
198struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio,
199				struct btrfs_io_context *bioc,
200				struct btrfs_device *scrub_dev,
201				unsigned long *dbitmap, int stripe_nsectors);
202void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio);
203
204void raid56_parity_cache_data_pages(struct btrfs_raid_bio *rbio,
205				    struct page **data_pages, u64 data_logical);
206
207int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info);
208void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info);
209
210#endif
211