1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _RAID10_H
3#define _RAID10_H
4
5/* Note: raid10_info.rdev can be set to NULL asynchronously by
6 * raid10_remove_disk.
7 * There are three safe ways to access raid10_info.rdev.
8 * 1/ when holding mddev->reconfig_mutex
9 * 2/ when resync/recovery/reshape is known to be happening - i.e. in code
10 *    that is called as part of performing resync/recovery/reshape.
11 * 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer
12 *    and if it is non-NULL, increment rdev->nr_pending before dropping the
13 *    RCU lock.
14 * When .rdev is set to NULL, the nr_pending count checked again and if it has
15 * been incremented, the pointer is put back in .rdev.
16 */
17
18struct raid10_info {
19	struct md_rdev	*rdev, *replacement;
20	sector_t	head_position;
21	int		recovery_disabled;	/* matches
22						 * mddev->recovery_disabled
23						 * when we shouldn't try
24						 * recovering this device.
25						 */
26};
27
28struct r10conf {
29	struct mddev		*mddev;
30	struct raid10_info	*mirrors;
31	struct raid10_info	*mirrors_new, *mirrors_old;
32	spinlock_t		device_lock;
33
34	/* geometry */
35	struct geom {
36		int		raid_disks;
37		int		near_copies;  /* number of copies laid out
38					       * raid0 style */
39		int		far_copies;   /* number of copies laid out
40					       * at large strides across drives
41					       */
42		int		far_offset;   /* far_copies are offset by 1
43					       * stripe instead of many
44					       */
45		sector_t	stride;	      /* distance between far copies.
46					       * This is size / far_copies unless
47					       * far_offset, in which case it is
48					       * 1 stripe.
49					       */
50		int             far_set_size; /* The number of devices in a set,
51					       * where a 'set' are devices that
52					       * contain far/offset copies of
53					       * each other.
54					       */
55		int		chunk_shift; /* shift from chunks to sectors */
56		sector_t	chunk_mask;
57	} prev, geo;
58	int			copies;	      /* near_copies * far_copies.
59					       * must be <= raid_disks
60					       */
61
62	sector_t		dev_sectors;  /* temp copy of
63					       * mddev->dev_sectors */
64	sector_t		reshape_progress;
65	sector_t		reshape_safe;
66	unsigned long		reshape_checkpoint;
67	sector_t		offset_diff;
68
69	struct list_head	retry_list;
70	/* A separate list of r1bio which just need raid_end_bio_io called.
71	 * This mustn't happen for writes which had any errors if the superblock
72	 * needs to be written.
73	 */
74	struct list_head	bio_end_io_list;
75
76	/* queue pending writes and submit them on unplug */
77	struct bio_list		pending_bio_list;
78
79	seqlock_t		resync_lock;
80	atomic_t		nr_pending;
81	int			nr_waiting;
82	int			nr_queued;
83	int			barrier;
84	int			array_freeze_pending;
85	sector_t		next_resync;
86	int			fullsync;  /* set to 1 if a full sync is needed,
87					    * (fresh device added).
88					    * Cleared when a sync completes.
89					    */
90	int			have_replacement; /* There is at least one
91						   * replacement device.
92						   */
93	wait_queue_head_t	wait_barrier;
94
95	mempool_t		r10bio_pool;
96	mempool_t		r10buf_pool;
97	struct page		*tmppage;
98	struct bio_set		bio_split;
99
100	/* When taking over an array from a different personality, we store
101	 * the new thread here until we fully activate the array.
102	 */
103	struct md_thread __rcu	*thread;
104
105	/*
106	 * Keep track of cluster resync window to send to other nodes.
107	 */
108	sector_t		cluster_sync_low;
109	sector_t		cluster_sync_high;
110};
111
112/*
113 * this is our 'private' RAID10 bio.
114 *
115 * it contains information about what kind of IO operations were started
116 * for this RAID10 operation, and about their status:
117 */
118
119struct r10bio {
120	atomic_t		remaining; /* 'have we finished' count,
121					    * used from IRQ handlers
122					    */
123	sector_t		sector;	/* virtual sector number */
124	int			sectors;
125	unsigned long		state;
126	struct mddev		*mddev;
127	/*
128	 * original bio going to /dev/mdx
129	 */
130	struct bio		*master_bio;
131	/*
132	 * if the IO is in READ direction, then this is where we read
133	 */
134	int			read_slot;
135
136	struct list_head	retry_list;
137	/*
138	 * if the IO is in WRITE direction, then multiple bios are used,
139	 * one for each copy.
140	 * When resyncing we also use one for each copy.
141	 * When reconstructing, we use 2 bios, one for read, one for write.
142	 * We choose the number when they are allocated.
143	 * We sometimes need an extra bio to write to the replacement.
144	 */
145	struct r10dev {
146		struct bio	*bio;
147		union {
148			struct bio	*repl_bio; /* used for resync and
149						    * writes */
150			struct md_rdev	*rdev;	   /* used for reads
151						    * (read_slot >= 0) */
152		};
153		sector_t	addr;
154		int		devnum;
155	} devs[];
156};
157
158/* bits for r10bio.state */
159enum r10bio_state {
160	R10BIO_Uptodate,
161	R10BIO_IsSync,
162	R10BIO_IsRecover,
163	R10BIO_IsReshape,
164	R10BIO_Degraded,
165/* Set ReadError on bios that experience a read error
166 * so that raid10d knows what to do with them.
167 */
168	R10BIO_ReadError,
169/* If a write for this request means we can clear some
170 * known-bad-block records, we set this flag.
171 */
172	R10BIO_MadeGood,
173	R10BIO_WriteError,
174/* During a reshape we might be performing IO on the
175 * 'previous' part of the array, in which case this
176 * flag is set
177 */
178	R10BIO_Previous,
179/* failfast devices did receive failfast requests. */
180	R10BIO_FailFast,
181	R10BIO_Discard,
182};
183#endif
184