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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _RAID5_H
2#define _RAID5_H
3
Linus Torvalds1da177e2005-04-16 15:20:36 -07004#include <linux/raid/xor.h>
Dan Williamsad283ea2009-08-29 19:09:26 -07005#include <linux/dmaengine.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07006
7/*
8 *
NeilBrownc4c16632011-07-26 11:34:20 +10009 * Each stripe contains one buffer per device. Each buffer can be in
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 * one of a number of states stored in "flags". Changes between
NeilBrownc4c16632011-07-26 11:34:20 +100011 * these states happen *almost* exclusively under the protection of the
12 * STRIPE_ACTIVE flag. Some very specific changes can happen in bi_end_io, and
13 * these are not protected by STRIPE_ACTIVE.
Linus Torvalds1da177e2005-04-16 15:20:36 -070014 *
15 * The flag bits that are used to represent these states are:
16 * R5_UPTODATE and R5_LOCKED
17 *
18 * State Empty == !UPTODATE, !LOCK
19 * We have no data, and there is no active request
20 * State Want == !UPTODATE, LOCK
21 * A read request is being submitted for this block
22 * State Dirty == UPTODATE, LOCK
23 * Some new data is in this buffer, and it is being written out
24 * State Clean == UPTODATE, !LOCK
25 * We have valid data which is the same as on disc
26 *
27 * The possible state transitions are:
28 *
29 * Empty -> Want - on read or write to get old data for parity calc
NeilBrownede7ee82011-12-23 10:17:52 +110030 * Empty -> Dirty - on compute_parity to satisfy write/sync request.
Linus Torvalds1da177e2005-04-16 15:20:36 -070031 * Empty -> Clean - on compute_block when computing a block for failed drive
32 * Want -> Empty - on failed read
33 * Want -> Clean - on successful completion of read request
34 * Dirty -> Clean - on successful completion of write request
35 * Dirty -> Clean - on failed write
36 * Clean -> Dirty - on compute_parity to satisfy write/sync (RECONSTRUCT or RMW)
37 *
38 * The Want->Empty, Want->Clean, Dirty->Clean, transitions
39 * all happen in b_end_io at interrupt time.
40 * Each sets the Uptodate bit before releasing the Lock bit.
41 * This leaves one multi-stage transition:
42 * Want->Dirty->Clean
43 * This is safe because thinking that a Clean buffer is actually dirty
44 * will at worst delay some action, and the stripe will be scheduled
45 * for attention after the transition is complete.
46 *
47 * There is one possibility that is not covered by these states. That
48 * is if one drive has failed and there is a spare being rebuilt. We
49 * can't distinguish between a clean block that has been generated
50 * from parity calculations, and a clean block that has been
51 * successfully written to the spare ( or to parity when resyncing).
52 * To distingush these states we have a stripe bit STRIPE_INSYNC that
53 * is set whenever a write is scheduled to the spare, or to the parity
54 * disc if there is no spare. A sync request clears this bit, and
55 * when we find it set with no buffers locked, we know the sync is
56 * complete.
57 *
58 * Buffers for the md device that arrive via make_request are attached
59 * to the appropriate stripe in one of two lists linked on b_reqnext.
60 * One list (bh_read) for read requests, one (bh_write) for write.
61 * There should never be more than one buffer on the two lists
62 * together, but we are not guaranteed of that so we allow for more.
63 *
64 * If a buffer is on the read list when the associated cache buffer is
65 * Uptodate, the data is copied into the read buffer and it's b_end_io
66 * routine is called. This may happen in the end_request routine only
67 * if the buffer has just successfully been read. end_request should
68 * remove the buffers from the list and then set the Uptodate bit on
69 * the buffer. Other threads may do this only if they first check
70 * that the Uptodate bit is set. Once they have checked that they may
71 * take buffers off the read queue.
72 *
73 * When a buffer on the write list is committed for write it is copied
74 * into the cache buffer, which is then marked dirty, and moved onto a
75 * third list, the written list (bh_written). Once both the parity
76 * block and the cached buffer are successfully written, any buffer on
77 * a written list can be returned with b_end_io.
78 *
NeilBrownc4c16632011-07-26 11:34:20 +100079 * The write list and read list both act as fifos. The read list,
80 * write list and written list are protected by the device_lock.
81 * The device_lock is only for list manipulations and will only be
82 * held for a very short time. It can be claimed from interrupts.
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 *
84 *
85 * Stripes in the stripe cache can be on one of two lists (or on
86 * neither). The "inactive_list" contains stripes which are not
87 * currently being used for any request. They can freely be reused
88 * for another stripe. The "handle_list" contains stripes that need
89 * to be handled in some way. Both of these are fifo queues. Each
90 * stripe is also (potentially) linked to a hash bucket in the hash
91 * table so that it can be found by sector number. Stripes that are
92 * not hashed must be on the inactive_list, and will normally be at
93 * the front. All stripes start life this way.
94 *
95 * The inactive_list, handle_list and hash bucket lists are all protected by the
96 * device_lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 * - stripes have a reference counter. If count==0, they are on a list.
98 * - If a stripe might need handling, STRIPE_HANDLE is set.
99 * - When refcount reaches zero, then if STRIPE_HANDLE it is put on
100 * handle_list else inactive_list
101 *
102 * This, combined with the fact that STRIPE_HANDLE is only ever
103 * cleared while a stripe has a non-zero count means that if the
104 * refcount is 0 and STRIPE_HANDLE is set, then it is on the
105 * handle_list and if recount is 0 and STRIPE_HANDLE is not set, then
106 * the stripe is on inactive_list.
107 *
108 * The possible transitions are:
109 * activate an unhashed/inactive stripe (get_active_stripe())
110 * lockdev check-hash unlink-stripe cnt++ clean-stripe hash-stripe unlockdev
111 * activate a hashed, possibly active stripe (get_active_stripe())
112 * lockdev check-hash if(!cnt++)unlink-stripe unlockdev
113 * attach a request to an active stripe (add_stripe_bh())
114 * lockdev attach-buffer unlockdev
115 * handle a stripe (handle_stripe())
NeilBrownc4c16632011-07-26 11:34:20 +1000116 * setSTRIPE_ACTIVE, clrSTRIPE_HANDLE ...
Dan Williams91c00922007-01-02 13:52:30 -0700117 * (lockdev check-buffers unlockdev) ..
118 * change-state ..
NeilBrownc4c16632011-07-26 11:34:20 +1000119 * record io/ops needed clearSTRIPE_ACTIVE schedule io/ops
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 * release an active stripe (release_stripe())
121 * lockdev if (!--cnt) { if STRIPE_HANDLE, add to handle_list else add to inactive-list } unlockdev
122 *
123 * The refcount counts each thread that have activated the stripe,
124 * plus raid5d if it is handling it, plus one for each active request
Dan Williams91c00922007-01-02 13:52:30 -0700125 * on a cached buffer, and plus one if the stripe is undergoing stripe
126 * operations.
127 *
NeilBrownc4c16632011-07-26 11:34:20 +1000128 * The stripe operations are:
Dan Williams91c00922007-01-02 13:52:30 -0700129 * -copying data between the stripe cache and user application buffers
130 * -computing blocks to save a disk access, or to recover a missing block
131 * -updating the parity on a write operation (reconstruct write and
132 * read-modify-write)
133 * -checking parity correctness
134 * -running i/o to disk
135 * These operations are carried out by raid5_run_ops which uses the async_tx
136 * api to (optionally) offload operations to dedicated hardware engines.
137 * When requesting an operation handle_stripe sets the pending bit for the
138 * operation and increments the count. raid5_run_ops is then run whenever
139 * the count is non-zero.
140 * There are some critical dependencies between the operations that prevent some
141 * from being requested while another is in flight.
142 * 1/ Parity check operations destroy the in cache version of the parity block,
143 * so we prevent parity dependent operations like writes and compute_blocks
144 * from starting while a check is in progress. Some dma engines can perform
145 * the check without damaging the parity block, in these cases the parity
146 * block is re-marked up to date (assuming the check was successful) and is
147 * not re-read from disk.
148 * 2/ When a write operation is requested we immediately lock the affected
149 * blocks, and mark them as not up to date. This causes new read requests
150 * to be held off, as well as parity checks and compute block operations.
151 * 3/ Once a compute block operation has been requested handle_stripe treats
152 * that block as if it is up to date. raid5_run_ops guaruntees that any
153 * operation that is dependent on the compute block result is initiated after
154 * the compute block completes.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 */
156
Dan Williamsecc65c92008-06-28 08:31:57 +1000157/*
NeilBrownc4c16632011-07-26 11:34:20 +1000158 * Operations state - intermediate states that are visible outside of
159 * STRIPE_ACTIVE.
Dan Williamsecc65c92008-06-28 08:31:57 +1000160 * In general _idle indicates nothing is running, _run indicates a data
161 * processing operation is active, and _result means the data processing result
162 * is stable and can be acted upon. For simple operations like biofill and
163 * compute that only have an _idle and _run state they are indicated with
164 * sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN)
165 */
166/**
167 * enum check_states - handles syncing / repairing a stripe
168 * @check_state_idle - check operations are quiesced
169 * @check_state_run - check operation is running
170 * @check_state_result - set outside lock when check result is valid
171 * @check_state_compute_run - check failed and we are repairing
172 * @check_state_compute_result - set outside lock when compute result is valid
173 */
174enum check_states {
175 check_state_idle = 0,
Dan Williamsac6b53b2009-07-14 13:40:19 -0700176 check_state_run, /* xor parity check */
177 check_state_run_q, /* q-parity check */
178 check_state_run_pq, /* pq dual parity check */
Dan Williamsecc65c92008-06-28 08:31:57 +1000179 check_state_check_result,
180 check_state_compute_run, /* parity repair */
181 check_state_compute_result,
182};
183
184/**
185 * enum reconstruct_states - handles writing or expanding a stripe
186 */
187enum reconstruct_states {
188 reconstruct_state_idle = 0,
Dan Williamsd8ee0722008-06-28 08:32:06 +1000189 reconstruct_state_prexor_drain_run, /* prexor-write */
Dan Williamsecc65c92008-06-28 08:31:57 +1000190 reconstruct_state_drain_run, /* write */
191 reconstruct_state_run, /* expand */
Dan Williamsd8ee0722008-06-28 08:32:06 +1000192 reconstruct_state_prexor_drain_result,
Dan Williamsecc65c92008-06-28 08:31:57 +1000193 reconstruct_state_drain_result,
194 reconstruct_state_result,
195};
196
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197struct stripe_head {
NeilBrownfccddba2006-01-06 00:20:33 -0800198 struct hlist_node hash;
NeilBrownd0dabf72009-03-31 14:39:38 +1100199 struct list_head lru; /* inactive_list or handle_list */
NeilBrownd1688a62011-10-11 16:49:52 +1100200 struct r5conf *raid_conf;
NeilBrown86b42c72009-03-31 15:19:03 +1100201 short generation; /* increments with every
202 * reshape */
NeilBrownd0dabf72009-03-31 14:39:38 +1100203 sector_t sector; /* sector of this row */
204 short pd_idx; /* parity disk index */
205 short qd_idx; /* 'Q' disk index for raid6 */
NeilBrown67cc2b82009-03-31 14:39:38 +1100206 short ddf_layout;/* use DDF ordering to calculate Q */
NeilBrownd0dabf72009-03-31 14:39:38 +1100207 unsigned long state; /* state flags */
208 atomic_t count; /* nr of active thread/requests */
NeilBrown72626682005-09-09 16:23:54 -0700209 int bm_seq; /* sequence number for bitmap flushes */
NeilBrownd0dabf72009-03-31 14:39:38 +1100210 int disks; /* disks in stripe */
Dan Williamsecc65c92008-06-28 08:31:57 +1000211 enum check_states check_state;
Dan Williams600aa102008-06-28 08:32:05 +1000212 enum reconstruct_states reconstruct_state;
Shaohua Lib17459c2012-07-19 16:01:31 +1000213 spinlock_t stripe_lock;
Dan Williams417b8d42009-10-16 16:25:22 +1100214 /**
215 * struct stripe_operations
Dan Williams91c00922007-01-02 13:52:30 -0700216 * @target - STRIPE_OP_COMPUTE_BLK target
Dan Williams417b8d42009-10-16 16:25:22 +1100217 * @target2 - 2nd compute target in the raid6 case
218 * @zero_sum_result - P and Q verification flags
219 * @request - async service request flags for raid_run_ops
Dan Williams91c00922007-01-02 13:52:30 -0700220 */
221 struct stripe_operations {
Dan Williamsac6b53b2009-07-14 13:40:19 -0700222 int target, target2;
Dan Williamsad283ea2009-08-29 19:09:26 -0700223 enum sum_check_flags zero_sum_result;
Dan Williams417b8d42009-10-16 16:25:22 +1100224 #ifdef CONFIG_MULTICORE_RAID456
225 unsigned long request;
226 wait_queue_head_t wait_for_ops;
227 #endif
Dan Williams91c00922007-01-02 13:52:30 -0700228 } ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 struct r5dev {
NeilBrown671488c2011-12-23 10:17:52 +1100230 /* rreq and rvec are used for the replacement device when
231 * writing data to both devices.
232 */
233 struct bio req, rreq;
234 struct bio_vec vec, rvec;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 struct page *page;
Dan Williams91c00922007-01-02 13:52:30 -0700236 struct bio *toread, *read, *towrite, *written;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 sector_t sector; /* sector of this page */
238 unsigned long flags;
239 } dev[1]; /* allocated with extra space depending of RAID geometry */
240};
Dan Williamsa4456852007-07-09 11:56:43 -0700241
242/* stripe_head_state - collects and tracks the dynamic state of a stripe_head
NeilBrownc4c16632011-07-26 11:34:20 +1000243 * for handle_stripe.
Dan Williamsa4456852007-07-09 11:56:43 -0700244 */
245struct stripe_head_state {
NeilBrown9a3e1102011-12-23 10:17:53 +1100246 /* 'syncing' means that we need to read all devices, either
247 * to check/correct parity, or to reconstruct a missing device.
248 * 'replacing' means we are replacing one or more drives and
249 * the source is valid at this point so we don't need to
250 * read all devices, just the replacement targets.
251 */
252 int syncing, expanding, expanded, replacing;
Dan Williamsa4456852007-07-09 11:56:43 -0700253 int locked, uptodate, to_read, to_write, failed, written;
Dan Williamsb5e98d62007-01-02 13:52:31 -0700254 int to_fill, compute, req_compute, non_overwrite;
NeilBrownf2b3b442011-07-26 11:35:19 +1000255 int failed_num[2];
NeilBrownf2b3b442011-07-26 11:35:19 +1000256 int p_failed, q_failed;
NeilBrownc5709ef2011-07-26 11:35:20 +1000257 int dec_preread_active;
258 unsigned long ops_request;
259
260 struct bio *return_bi;
NeilBrown3cb03002011-10-11 16:45:26 +1100261 struct md_rdev *blocked_rdev;
NeilBrownbc2607f2011-07-28 11:39:22 +1000262 int handle_bad_blocks;
Dan Williamsa4456852007-07-09 11:56:43 -0700263};
264
NeilBrown671488c2011-12-23 10:17:52 +1100265/* Flags for struct r5dev.flags */
266enum r5dev_flags {
267 R5_UPTODATE, /* page contains current data */
268 R5_LOCKED, /* IO has been submitted on "req" */
NeilBrown977df362011-12-23 10:17:53 +1100269 R5_DOUBLE_LOCKED,/* Cannot clear R5_LOCKED until 2 writes complete */
NeilBrown671488c2011-12-23 10:17:52 +1100270 R5_OVERWRITE, /* towrite covers whole page */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271/* and some that are internal to handle_stripe */
NeilBrown671488c2011-12-23 10:17:52 +1100272 R5_Insync, /* rdev && rdev->in_sync at start */
273 R5_Wantread, /* want to schedule a read */
274 R5_Wantwrite,
275 R5_Overlap, /* There is a pending overlapping request
276 * on this block */
majianpeng3f9e7c12012-07-31 10:04:21 +1000277 R5_ReadNoMerge, /* prevent bio from merging in block-layer */
NeilBrown671488c2011-12-23 10:17:52 +1100278 R5_ReadError, /* seen a read error here recently */
279 R5_ReWrite, /* have tried to over-write the readerror */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280
NeilBrown671488c2011-12-23 10:17:52 +1100281 R5_Expanded, /* This block now has post-expand data */
282 R5_Wantcompute, /* compute_block in progress treat as
283 * uptodate
284 */
285 R5_Wantfill, /* dev->toread contains a bio that needs
286 * filling
287 */
288 R5_Wantdrain, /* dev->towrite needs to be drained */
289 R5_WantFUA, /* Write should be FUA */
Shaohua Libc0934f2012-05-22 13:55:05 +1000290 R5_SyncIO, /* The IO is sync */
NeilBrown671488c2011-12-23 10:17:52 +1100291 R5_WriteError, /* got a write error - need to record it */
292 R5_MadeGood, /* A bad block has been fixed by writing to it */
293 R5_ReadRepl, /* Will/did read from replacement rather than orig */
294 R5_MadeGoodRepl,/* A bad block on the replacement device has been
295 * fixed by writing to it */
NeilBrown9a3e1102011-12-23 10:17:53 +1100296 R5_NeedReplace, /* This device has a replacement which is not
297 * up-to-date at this stripe. */
298 R5_WantReplace, /* We need to update the replacement, we have read
299 * data in, and now is a good time to write it out.
300 */
Shaohua Li620125f2012-10-11 13:49:05 +1100301 R5_Discard, /* Discard the stripe */
NeilBrown671488c2011-12-23 10:17:52 +1100302};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303
304/*
305 * Stripe state
306 */
NeilBrown83206d62011-07-26 11:19:49 +1000307enum {
NeilBrownc4c16632011-07-26 11:34:20 +1000308 STRIPE_ACTIVE,
NeilBrown83206d62011-07-26 11:19:49 +1000309 STRIPE_HANDLE,
310 STRIPE_SYNC_REQUESTED,
311 STRIPE_SYNCING,
312 STRIPE_INSYNC,
313 STRIPE_PREREAD_ACTIVE,
314 STRIPE_DELAYED,
315 STRIPE_DEGRADED,
316 STRIPE_BIT_DELAY,
317 STRIPE_EXPANDING,
318 STRIPE_EXPAND_SOURCE,
319 STRIPE_EXPAND_READY,
320 STRIPE_IO_STARTED, /* do not count towards 'bypass_count' */
321 STRIPE_FULL_WRITE, /* all blocks are set to be overwritten */
322 STRIPE_BIOFILL_RUN,
323 STRIPE_COMPUTE_RUN,
324 STRIPE_OPS_REQ_PENDING,
Shaohua Li8811b592012-08-02 08:33:00 +1000325 STRIPE_ON_UNPLUG_LIST,
NeilBrown83206d62011-07-26 11:19:49 +1000326};
Dan Williams417b8d42009-10-16 16:25:22 +1100327
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328/*
Dan Williamsecc65c92008-06-28 08:31:57 +1000329 * Operation request flags
Dan Williams91c00922007-01-02 13:52:30 -0700330 */
NeilBrownede7ee82011-12-23 10:17:52 +1100331enum {
332 STRIPE_OP_BIOFILL,
333 STRIPE_OP_COMPUTE_BLK,
334 STRIPE_OP_PREXOR,
335 STRIPE_OP_BIODRAIN,
336 STRIPE_OP_RECONSTRUCT,
337 STRIPE_OP_CHECK,
338};
Dan Williams91c00922007-01-02 13:52:30 -0700339/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 * Plugging:
341 *
342 * To improve write throughput, we need to delay the handling of some
343 * stripes until there has been a chance that several write requests
344 * for the one stripe have all been collected.
345 * In particular, any write request that would require pre-reading
346 * is put on a "delayed" queue until there are no stripes currently
347 * in a pre-read phase. Further, if the "delayed" queue is empty when
348 * a stripe is put on it then we "plug" the queue and do not process it
349 * until an unplug call is made. (the unplug_io_fn() is called).
350 *
351 * When preread is initiated on a stripe, we set PREREAD_ACTIVE and add
352 * it to the count of prereading stripes.
353 * When write is initiated, or the stripe refcnt == 0 (just in case) we
354 * clear the PREREAD_ACTIVE flag and decrement the count
NeilBrownb5c124a2006-10-03 01:15:45 -0700355 * Whenever the 'handle' queue is empty and the device is not plugged, we
356 * move any strips from delayed to handle and clear the DELAYED flag and set
357 * PREREAD_ACTIVE.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 * In stripe_handle, if we find pre-reading is necessary, we do it if
359 * PREREAD_ACTIVE is set, else we set DELAYED which will send it to the delayed queue.
NeilBrownc4c16632011-07-26 11:34:20 +1000360 * HANDLE gets cleared if stripe_handle leaves nothing locked.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 */
Christoph Hellwigef740c32009-03-31 14:27:03 +1100362
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363
364struct disk_info {
NeilBrown671488c2011-12-23 10:17:52 +1100365 struct md_rdev *rdev, *replacement;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366};
367
NeilBrownd1688a62011-10-11 16:49:52 +1100368struct r5conf {
NeilBrownfccddba2006-01-06 00:20:33 -0800369 struct hlist_head *stripe_hashtbl;
NeilBrownfd01b882011-10-11 16:47:53 +1100370 struct mddev *mddev;
Andre Noll09c9e5f2009-06-18 08:45:55 +1000371 int chunk_sectors;
372 int level, algorithm;
NeilBrown16a53ec2006-06-26 00:27:38 -0700373 int max_degraded;
NeilBrown02c2de82006-10-03 01:15:47 -0700374 int raid_disks;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 int max_nr_stripes;
376
NeilBrownfef9c612009-03-31 15:16:46 +1100377 /* reshape_progress is the leading edge of a 'reshape'
378 * It has value MaxSector when no reshape is happening
379 * If delta_disks < 0, it is the last sector we started work on,
380 * else is it the next sector to work on.
381 */
382 sector_t reshape_progress;
383 /* reshape_safe is the trailing edge of a reshape. We know that
384 * before (or after) this address, all reshape has completed.
385 */
386 sector_t reshape_safe;
NeilBrown7ecaa1e2006-03-27 01:18:08 -0800387 int previous_raid_disks;
Andre Noll09c9e5f2009-06-18 08:45:55 +1000388 int prev_chunk_sectors;
389 int prev_algo;
NeilBrown86b42c72009-03-31 15:19:03 +1100390 short generation; /* increments with every reshape */
NeilBrownc8f517c2009-03-31 15:28:40 +1100391 unsigned long reshape_checkpoint; /* Time we last updated
392 * metadata */
NeilBrownb5254dd2012-05-21 09:27:01 +1000393 long long min_offset_diff; /* minimum difference between
394 * data_offset and
395 * new_data_offset across all
396 * devices. May be negative,
397 * but is closest to zero.
398 */
NeilBrown7ecaa1e2006-03-27 01:18:08 -0800399
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 struct list_head handle_list; /* stripes needing handling */
Dan Williams8b3e6cd2008-04-28 02:15:53 -0700401 struct list_head hold_list; /* preread ready stripes */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 struct list_head delayed_list; /* stripes that have plugged requests */
NeilBrown72626682005-09-09 16:23:54 -0700403 struct list_head bitmap_list; /* stripes delaying awaiting bitmap update */
Raz Ben-Jehuda(caro)46031f92006-12-10 02:20:47 -0800404 struct bio *retry_read_aligned; /* currently retrying aligned bios */
405 struct bio *retry_read_aligned_list; /* aligned bios retry list */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 atomic_t preread_active_stripes; /* stripes with scheduled io */
Raz Ben-Jehuda(caro)46031f92006-12-10 02:20:47 -0800407 atomic_t active_aligned_reads;
Dan Williams8b3e6cd2008-04-28 02:15:53 -0700408 atomic_t pending_full_writes; /* full write backlog */
409 int bypass_count; /* bypassed prereads */
410 int bypass_threshold; /* preread nice */
411 struct list_head *last_hold; /* detect hold_list promotions */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412
NeilBrownf6705572006-03-27 01:18:11 -0800413 atomic_t reshape_stripes; /* stripes with pending writes for reshape */
NeilBrownad01c9e2006-03-27 01:18:07 -0800414 /* unfortunately we need two cache names as we temporarily have
415 * two caches.
416 */
417 int active_name;
NeilBrownf4be6b42010-06-01 19:37:25 +1000418 char cache_name[2][32];
Christoph Lametere18b8902006-12-06 20:33:20 -0800419 struct kmem_cache *slab_cache; /* for allocating stripes */
NeilBrown72626682005-09-09 16:23:54 -0700420
421 int seq_flush, seq_write;
422 int quiesce;
423
424 int fullsync; /* set to 1 if a full sync is needed,
425 * (fresh device added).
426 * Cleared when a sync completes.
427 */
NeilBrown7f0da592011-07-28 11:39:22 +1000428 int recovery_disabled;
Dan Williams36d1c642009-07-14 11:48:22 -0700429 /* per cpu variables */
430 struct raid5_percpu {
431 struct page *spare_page; /* Used when checking P/Q in raid6 */
Dan Williamsd6f38f32009-07-14 11:50:52 -0700432 void *scribble; /* space for constructing buffer
433 * lists and performing address
434 * conversions
435 */
Tejun Heoa29d8b82010-02-02 14:39:15 +0900436 } __percpu *percpu;
Dan Williamsd6f38f32009-07-14 11:50:52 -0700437 size_t scribble_len; /* size of scribble region must be
438 * associated with conf to handle
439 * cpu hotplug while reshaping
440 */
Dan Williams36d1c642009-07-14 11:48:22 -0700441#ifdef CONFIG_HOTPLUG_CPU
442 struct notifier_block cpu_notify;
443#endif
NeilBrownca65b732006-01-06 00:20:17 -0800444
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 /*
446 * Free stripes pool
447 */
448 atomic_t active_stripes;
449 struct list_head inactive_list;
450 wait_queue_head_t wait_for_stripe;
451 wait_queue_head_t wait_for_overlap;
452 int inactive_blocked; /* release of inactive stripes blocked,
453 * waiting for 25% to be free
NeilBrownad01c9e2006-03-27 01:18:07 -0800454 */
455 int pool_size; /* number of disks in stripeheads in pool */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 spinlock_t device_lock;
NeilBrownb55e6bf2006-03-27 01:18:06 -0800457 struct disk_info *disks;
NeilBrown91adb562009-03-31 14:39:39 +1100458
459 /* When taking over an array from a different personality, we store
460 * the new thread here until we fully activate the array.
461 */
NeilBrown2b8bf342011-10-11 16:48:23 +1100462 struct md_thread *thread;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463};
464
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465/*
466 * Our supported algorithms
467 */
NeilBrown99c0fb52009-03-31 14:39:38 +1100468#define ALGORITHM_LEFT_ASYMMETRIC 0 /* Rotating Parity N with Data Restart */
469#define ALGORITHM_RIGHT_ASYMMETRIC 1 /* Rotating Parity 0 with Data Restart */
470#define ALGORITHM_LEFT_SYMMETRIC 2 /* Rotating Parity N with Data Continuation */
471#define ALGORITHM_RIGHT_SYMMETRIC 3 /* Rotating Parity 0 with Data Continuation */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472
NeilBrown99c0fb52009-03-31 14:39:38 +1100473/* Define non-rotating (raid4) algorithms. These allow
474 * conversion of raid4 to raid5.
475 */
476#define ALGORITHM_PARITY_0 4 /* P or P,Q are initial devices */
477#define ALGORITHM_PARITY_N 5 /* P or P,Q are final devices. */
478
479/* DDF RAID6 layouts differ from md/raid6 layouts in two ways.
480 * Firstly, the exact positioning of the parity block is slightly
481 * different between the 'LEFT_*' modes of md and the "_N_*" modes
482 * of DDF.
483 * Secondly, or order of datablocks over which the Q syndrome is computed
484 * is different.
485 * Consequently we have different layouts for DDF/raid6 than md/raid6.
486 * These layouts are from the DDFv1.2 spec.
487 * Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but
488 * leaves RLQ=3 as 'Vendor Specific'
489 */
490
491#define ALGORITHM_ROTATING_ZERO_RESTART 8 /* DDF PRL=6 RLQ=1 */
492#define ALGORITHM_ROTATING_N_RESTART 9 /* DDF PRL=6 RLQ=2 */
493#define ALGORITHM_ROTATING_N_CONTINUE 10 /*DDF PRL=6 RLQ=3 */
494
495
496/* For every RAID5 algorithm we define a RAID6 algorithm
497 * with exactly the same layout for data and parity, and
498 * with the Q block always on the last device (N-1).
499 * This allows trivial conversion from RAID5 to RAID6
500 */
501#define ALGORITHM_LEFT_ASYMMETRIC_6 16
502#define ALGORITHM_RIGHT_ASYMMETRIC_6 17
503#define ALGORITHM_LEFT_SYMMETRIC_6 18
504#define ALGORITHM_RIGHT_SYMMETRIC_6 19
505#define ALGORITHM_PARITY_0_6 20
506#define ALGORITHM_PARITY_N_6 ALGORITHM_PARITY_N
507
508static inline int algorithm_valid_raid5(int layout)
509{
510 return (layout >= 0) &&
511 (layout <= 5);
512}
513static inline int algorithm_valid_raid6(int layout)
514{
515 return (layout >= 0 && layout <= 5)
516 ||
NeilBrowne4424fe2009-10-16 16:27:34 +1100517 (layout >= 8 && layout <= 10)
NeilBrown99c0fb52009-03-31 14:39:38 +1100518 ||
519 (layout >= 16 && layout <= 20);
520}
521
522static inline int algorithm_is_DDF(int layout)
523{
524 return layout >= 8 && layout <= 10;
525}
NeilBrown11d8a6e2010-07-26 11:57:07 +1000526
NeilBrownfd01b882011-10-11 16:47:53 +1100527extern int md_raid5_congested(struct mddev *mddev, int bits);
NeilBrownd1688a62011-10-11 16:49:52 +1100528extern void md_raid5_kick_device(struct r5conf *conf);
NeilBrownfd01b882011-10-11 16:47:53 +1100529extern int raid5_set_cache_size(struct mddev *mddev, int size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530#endif