Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef _RAID5_H |
| 2 | #define _RAID5_H |
| 3 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4 | #include <linux/raid/xor.h> |
Dan Williams | ad283ea | 2009-08-29 19:09:26 -0700 | [diff] [blame] | 5 | #include <linux/dmaengine.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6 | |
| 7 | /* |
| 8 | * |
| 9 | * Each stripe contains one buffer per disc. Each buffer can be in |
| 10 | * one of a number of states stored in "flags". Changes between |
| 11 | * these states happen *almost* exclusively under a per-stripe |
| 12 | * spinlock. Some very specific changes can happen in bi_end_io, and |
| 13 | * these are not protected by the spin lock. |
| 14 | * |
| 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 |
| 30 | * Empty -> Dirty - on compute_parity to satisfy write/sync request.(RECONSTRUCT_WRITE) |
| 31 | * 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 | * |
| 79 | * The write list and read list both act as fifos. The read list is |
| 80 | * protected by the device_lock. The write and written lists are |
| 81 | * protected by the stripe lock. The device_lock, which can be |
| 82 | * claimed while the stipe lock is held, is only for list |
| 83 | * manipulations and will only be held for a very short time. It can |
| 84 | * be claimed from interrupts. |
| 85 | * |
| 86 | * |
| 87 | * Stripes in the stripe cache can be on one of two lists (or on |
| 88 | * neither). The "inactive_list" contains stripes which are not |
| 89 | * currently being used for any request. They can freely be reused |
| 90 | * for another stripe. The "handle_list" contains stripes that need |
| 91 | * to be handled in some way. Both of these are fifo queues. Each |
| 92 | * stripe is also (potentially) linked to a hash bucket in the hash |
| 93 | * table so that it can be found by sector number. Stripes that are |
| 94 | * not hashed must be on the inactive_list, and will normally be at |
| 95 | * the front. All stripes start life this way. |
| 96 | * |
| 97 | * The inactive_list, handle_list and hash bucket lists are all protected by the |
| 98 | * device_lock. |
| 99 | * - stripes on the inactive_list never have their stripe_lock held. |
| 100 | * - stripes have a reference counter. If count==0, they are on a list. |
| 101 | * - If a stripe might need handling, STRIPE_HANDLE is set. |
| 102 | * - When refcount reaches zero, then if STRIPE_HANDLE it is put on |
| 103 | * handle_list else inactive_list |
| 104 | * |
| 105 | * This, combined with the fact that STRIPE_HANDLE is only ever |
| 106 | * cleared while a stripe has a non-zero count means that if the |
| 107 | * refcount is 0 and STRIPE_HANDLE is set, then it is on the |
| 108 | * handle_list and if recount is 0 and STRIPE_HANDLE is not set, then |
| 109 | * the stripe is on inactive_list. |
| 110 | * |
| 111 | * The possible transitions are: |
| 112 | * activate an unhashed/inactive stripe (get_active_stripe()) |
| 113 | * lockdev check-hash unlink-stripe cnt++ clean-stripe hash-stripe unlockdev |
| 114 | * activate a hashed, possibly active stripe (get_active_stripe()) |
| 115 | * lockdev check-hash if(!cnt++)unlink-stripe unlockdev |
| 116 | * attach a request to an active stripe (add_stripe_bh()) |
| 117 | * lockdev attach-buffer unlockdev |
| 118 | * handle a stripe (handle_stripe()) |
Dan Williams | 91c0092 | 2007-01-02 13:52:30 -0700 | [diff] [blame] | 119 | * lockstripe clrSTRIPE_HANDLE ... |
| 120 | * (lockdev check-buffers unlockdev) .. |
| 121 | * change-state .. |
| 122 | * record io/ops needed unlockstripe schedule io/ops |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | * release an active stripe (release_stripe()) |
| 124 | * lockdev if (!--cnt) { if STRIPE_HANDLE, add to handle_list else add to inactive-list } unlockdev |
| 125 | * |
| 126 | * The refcount counts each thread that have activated the stripe, |
| 127 | * plus raid5d if it is handling it, plus one for each active request |
Dan Williams | 91c0092 | 2007-01-02 13:52:30 -0700 | [diff] [blame] | 128 | * on a cached buffer, and plus one if the stripe is undergoing stripe |
| 129 | * operations. |
| 130 | * |
| 131 | * Stripe operations are performed outside the stripe lock, |
| 132 | * the stripe operations are: |
| 133 | * -copying data between the stripe cache and user application buffers |
| 134 | * -computing blocks to save a disk access, or to recover a missing block |
| 135 | * -updating the parity on a write operation (reconstruct write and |
| 136 | * read-modify-write) |
| 137 | * -checking parity correctness |
| 138 | * -running i/o to disk |
| 139 | * These operations are carried out by raid5_run_ops which uses the async_tx |
| 140 | * api to (optionally) offload operations to dedicated hardware engines. |
| 141 | * When requesting an operation handle_stripe sets the pending bit for the |
| 142 | * operation and increments the count. raid5_run_ops is then run whenever |
| 143 | * the count is non-zero. |
| 144 | * There are some critical dependencies between the operations that prevent some |
| 145 | * from being requested while another is in flight. |
| 146 | * 1/ Parity check operations destroy the in cache version of the parity block, |
| 147 | * so we prevent parity dependent operations like writes and compute_blocks |
| 148 | * from starting while a check is in progress. Some dma engines can perform |
| 149 | * the check without damaging the parity block, in these cases the parity |
| 150 | * block is re-marked up to date (assuming the check was successful) and is |
| 151 | * not re-read from disk. |
| 152 | * 2/ When a write operation is requested we immediately lock the affected |
| 153 | * blocks, and mark them as not up to date. This causes new read requests |
| 154 | * to be held off, as well as parity checks and compute block operations. |
| 155 | * 3/ Once a compute block operation has been requested handle_stripe treats |
| 156 | * that block as if it is up to date. raid5_run_ops guaruntees that any |
| 157 | * operation that is dependent on the compute block result is initiated after |
| 158 | * the compute block completes. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 159 | */ |
| 160 | |
Dan Williams | ecc65c9 | 2008-06-28 08:31:57 +1000 | [diff] [blame] | 161 | /* |
| 162 | * Operations state - intermediate states that are visible outside of sh->lock |
| 163 | * In general _idle indicates nothing is running, _run indicates a data |
| 164 | * processing operation is active, and _result means the data processing result |
| 165 | * is stable and can be acted upon. For simple operations like biofill and |
| 166 | * compute that only have an _idle and _run state they are indicated with |
| 167 | * sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN) |
| 168 | */ |
| 169 | /** |
| 170 | * enum check_states - handles syncing / repairing a stripe |
| 171 | * @check_state_idle - check operations are quiesced |
| 172 | * @check_state_run - check operation is running |
| 173 | * @check_state_result - set outside lock when check result is valid |
| 174 | * @check_state_compute_run - check failed and we are repairing |
| 175 | * @check_state_compute_result - set outside lock when compute result is valid |
| 176 | */ |
| 177 | enum check_states { |
| 178 | check_state_idle = 0, |
Dan Williams | ac6b53b | 2009-07-14 13:40:19 -0700 | [diff] [blame] | 179 | check_state_run, /* xor parity check */ |
| 180 | check_state_run_q, /* q-parity check */ |
| 181 | check_state_run_pq, /* pq dual parity check */ |
Dan Williams | ecc65c9 | 2008-06-28 08:31:57 +1000 | [diff] [blame] | 182 | check_state_check_result, |
| 183 | check_state_compute_run, /* parity repair */ |
| 184 | check_state_compute_result, |
| 185 | }; |
| 186 | |
| 187 | /** |
| 188 | * enum reconstruct_states - handles writing or expanding a stripe |
| 189 | */ |
| 190 | enum reconstruct_states { |
| 191 | reconstruct_state_idle = 0, |
Dan Williams | d8ee072 | 2008-06-28 08:32:06 +1000 | [diff] [blame] | 192 | reconstruct_state_prexor_drain_run, /* prexor-write */ |
Dan Williams | ecc65c9 | 2008-06-28 08:31:57 +1000 | [diff] [blame] | 193 | reconstruct_state_drain_run, /* write */ |
| 194 | reconstruct_state_run, /* expand */ |
Dan Williams | d8ee072 | 2008-06-28 08:32:06 +1000 | [diff] [blame] | 195 | reconstruct_state_prexor_drain_result, |
Dan Williams | ecc65c9 | 2008-06-28 08:31:57 +1000 | [diff] [blame] | 196 | reconstruct_state_drain_result, |
| 197 | reconstruct_state_result, |
| 198 | }; |
| 199 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | struct stripe_head { |
NeilBrown | fccddba | 2006-01-06 00:20:33 -0800 | [diff] [blame] | 201 | struct hlist_node hash; |
NeilBrown | d0dabf7 | 2009-03-31 14:39:38 +1100 | [diff] [blame] | 202 | struct list_head lru; /* inactive_list or handle_list */ |
| 203 | struct raid5_private_data *raid_conf; |
NeilBrown | 86b42c7 | 2009-03-31 15:19:03 +1100 | [diff] [blame] | 204 | short generation; /* increments with every |
| 205 | * reshape */ |
NeilBrown | d0dabf7 | 2009-03-31 14:39:38 +1100 | [diff] [blame] | 206 | sector_t sector; /* sector of this row */ |
| 207 | short pd_idx; /* parity disk index */ |
| 208 | short qd_idx; /* 'Q' disk index for raid6 */ |
NeilBrown | 67cc2b8 | 2009-03-31 14:39:38 +1100 | [diff] [blame] | 209 | short ddf_layout;/* use DDF ordering to calculate Q */ |
NeilBrown | d0dabf7 | 2009-03-31 14:39:38 +1100 | [diff] [blame] | 210 | unsigned long state; /* state flags */ |
| 211 | atomic_t count; /* nr of active thread/requests */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | spinlock_t lock; |
NeilBrown | 7262668 | 2005-09-09 16:23:54 -0700 | [diff] [blame] | 213 | int bm_seq; /* sequence number for bitmap flushes */ |
NeilBrown | d0dabf7 | 2009-03-31 14:39:38 +1100 | [diff] [blame] | 214 | int disks; /* disks in stripe */ |
Dan Williams | ecc65c9 | 2008-06-28 08:31:57 +1000 | [diff] [blame] | 215 | enum check_states check_state; |
Dan Williams | 600aa10 | 2008-06-28 08:32:05 +1000 | [diff] [blame] | 216 | enum reconstruct_states reconstruct_state; |
Dan Williams | 417b8d4 | 2009-10-16 16:25:22 +1100 | [diff] [blame] | 217 | /** |
| 218 | * struct stripe_operations |
Dan Williams | 91c0092 | 2007-01-02 13:52:30 -0700 | [diff] [blame] | 219 | * @target - STRIPE_OP_COMPUTE_BLK target |
Dan Williams | 417b8d4 | 2009-10-16 16:25:22 +1100 | [diff] [blame] | 220 | * @target2 - 2nd compute target in the raid6 case |
| 221 | * @zero_sum_result - P and Q verification flags |
| 222 | * @request - async service request flags for raid_run_ops |
Dan Williams | 91c0092 | 2007-01-02 13:52:30 -0700 | [diff] [blame] | 223 | */ |
| 224 | struct stripe_operations { |
Dan Williams | ac6b53b | 2009-07-14 13:40:19 -0700 | [diff] [blame] | 225 | int target, target2; |
Dan Williams | ad283ea | 2009-08-29 19:09:26 -0700 | [diff] [blame] | 226 | enum sum_check_flags zero_sum_result; |
Dan Williams | 417b8d4 | 2009-10-16 16:25:22 +1100 | [diff] [blame] | 227 | #ifdef CONFIG_MULTICORE_RAID456 |
| 228 | unsigned long request; |
| 229 | wait_queue_head_t wait_for_ops; |
| 230 | #endif |
Dan Williams | 91c0092 | 2007-01-02 13:52:30 -0700 | [diff] [blame] | 231 | } ops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | struct r5dev { |
| 233 | struct bio req; |
| 234 | struct bio_vec vec; |
| 235 | struct page *page; |
Dan Williams | 91c0092 | 2007-01-02 13:52:30 -0700 | [diff] [blame] | 236 | struct bio *toread, *read, *towrite, *written; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | sector_t sector; /* sector of this page */ |
| 238 | unsigned long flags; |
| 239 | } dev[1]; /* allocated with extra space depending of RAID geometry */ |
| 240 | }; |
Dan Williams | a445685 | 2007-07-09 11:56:43 -0700 | [diff] [blame] | 241 | |
| 242 | /* stripe_head_state - collects and tracks the dynamic state of a stripe_head |
| 243 | * for handle_stripe. It is only valid under spin_lock(sh->lock); |
| 244 | */ |
| 245 | struct stripe_head_state { |
| 246 | int syncing, expanding, expanded; |
| 247 | int locked, uptodate, to_read, to_write, failed, written; |
Dan Williams | b5e98d6 | 2007-01-02 13:52:31 -0700 | [diff] [blame] | 248 | int to_fill, compute, req_compute, non_overwrite; |
Dan Williams | a445685 | 2007-07-09 11:56:43 -0700 | [diff] [blame] | 249 | int failed_num; |
Dan Williams | ecc65c9 | 2008-06-28 08:31:57 +1000 | [diff] [blame] | 250 | unsigned long ops_request; |
Dan Williams | a445685 | 2007-07-09 11:56:43 -0700 | [diff] [blame] | 251 | }; |
| 252 | |
| 253 | /* r6_state - extra state data only relevant to r6 */ |
| 254 | struct r6_state { |
NeilBrown | 34e04e8 | 2009-03-31 15:10:16 +1100 | [diff] [blame] | 255 | int p_failed, q_failed, failed_num[2]; |
Dan Williams | a445685 | 2007-07-09 11:56:43 -0700 | [diff] [blame] | 256 | }; |
| 257 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | /* Flags */ |
| 259 | #define R5_UPTODATE 0 /* page contains current data */ |
| 260 | #define R5_LOCKED 1 /* IO has been submitted on "req" */ |
| 261 | #define R5_OVERWRITE 2 /* towrite covers whole page */ |
| 262 | /* and some that are internal to handle_stripe */ |
| 263 | #define R5_Insync 3 /* rdev && rdev->in_sync at start */ |
| 264 | #define R5_Wantread 4 /* want to schedule a read */ |
| 265 | #define R5_Wantwrite 5 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 266 | #define R5_Overlap 7 /* There is a pending overlapping request on this block */ |
NeilBrown | 4e5314b | 2005-11-08 21:39:22 -0800 | [diff] [blame] | 267 | #define R5_ReadError 8 /* seen a read error here recently */ |
| 268 | #define R5_ReWrite 9 /* have tried to over-write the readerror */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | |
NeilBrown | ccfcc3c | 2006-03-27 01:18:09 -0800 | [diff] [blame] | 270 | #define R5_Expanded 10 /* This block now has post-expand data */ |
Dan Williams | 91c0092 | 2007-01-02 13:52:30 -0700 | [diff] [blame] | 271 | #define R5_Wantcompute 11 /* compute_block in progress treat as |
| 272 | * uptodate |
| 273 | */ |
| 274 | #define R5_Wantfill 12 /* dev->toread contains a bio that needs |
| 275 | * filling |
| 276 | */ |
Dan Williams | d8ee072 | 2008-06-28 08:32:06 +1000 | [diff] [blame] | 277 | #define R5_Wantdrain 13 /* dev->towrite needs to be drained */ |
Tejun Heo | e9c7469 | 2010-09-03 11:56:18 +0200 | [diff] [blame] | 278 | #define R5_WantFUA 14 /* Write should be FUA */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | /* |
| 280 | * Write method |
| 281 | */ |
| 282 | #define RECONSTRUCT_WRITE 1 |
| 283 | #define READ_MODIFY_WRITE 2 |
| 284 | /* not a write method, but a compute_parity mode */ |
| 285 | #define CHECK_PARITY 3 |
Dan Williams | f701d58 | 2009-03-31 15:09:39 +1100 | [diff] [blame] | 286 | /* Additional compute_parity mode -- updates the parity w/o LOCKING */ |
| 287 | #define UPDATE_PARITY 4 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 288 | |
| 289 | /* |
| 290 | * Stripe state |
| 291 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 292 | #define STRIPE_HANDLE 2 |
| 293 | #define STRIPE_SYNCING 3 |
| 294 | #define STRIPE_INSYNC 4 |
| 295 | #define STRIPE_PREREAD_ACTIVE 5 |
| 296 | #define STRIPE_DELAYED 6 |
NeilBrown | 7262668 | 2005-09-09 16:23:54 -0700 | [diff] [blame] | 297 | #define STRIPE_DEGRADED 7 |
| 298 | #define STRIPE_BIT_DELAY 8 |
NeilBrown | 7ecaa1e | 2006-03-27 01:18:08 -0800 | [diff] [blame] | 299 | #define STRIPE_EXPANDING 9 |
NeilBrown | ccfcc3c | 2006-03-27 01:18:09 -0800 | [diff] [blame] | 300 | #define STRIPE_EXPAND_SOURCE 10 |
| 301 | #define STRIPE_EXPAND_READY 11 |
Dan Williams | 8b3e6cd | 2008-04-28 02:15:53 -0700 | [diff] [blame] | 302 | #define STRIPE_IO_STARTED 12 /* do not count towards 'bypass_count' */ |
| 303 | #define STRIPE_FULL_WRITE 13 /* all blocks are set to be overwritten */ |
Dan Williams | ecc65c9 | 2008-06-28 08:31:57 +1000 | [diff] [blame] | 304 | #define STRIPE_BIOFILL_RUN 14 |
| 305 | #define STRIPE_COMPUTE_RUN 15 |
Dan Williams | 417b8d4 | 2009-10-16 16:25:22 +1100 | [diff] [blame] | 306 | #define STRIPE_OPS_REQ_PENDING 16 |
| 307 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 308 | /* |
Dan Williams | ecc65c9 | 2008-06-28 08:31:57 +1000 | [diff] [blame] | 309 | * Operation request flags |
Dan Williams | 91c0092 | 2007-01-02 13:52:30 -0700 | [diff] [blame] | 310 | */ |
| 311 | #define STRIPE_OP_BIOFILL 0 |
| 312 | #define STRIPE_OP_COMPUTE_BLK 1 |
| 313 | #define STRIPE_OP_PREXOR 2 |
| 314 | #define STRIPE_OP_BIODRAIN 3 |
Dan Williams | ac6b53b | 2009-07-14 13:40:19 -0700 | [diff] [blame] | 315 | #define STRIPE_OP_RECONSTRUCT 4 |
Dan Williams | 91c0092 | 2007-01-02 13:52:30 -0700 | [diff] [blame] | 316 | #define STRIPE_OP_CHECK 5 |
Dan Williams | 91c0092 | 2007-01-02 13:52:30 -0700 | [diff] [blame] | 317 | |
Dan Williams | 91c0092 | 2007-01-02 13:52:30 -0700 | [diff] [blame] | 318 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | * Plugging: |
| 320 | * |
| 321 | * To improve write throughput, we need to delay the handling of some |
| 322 | * stripes until there has been a chance that several write requests |
| 323 | * for the one stripe have all been collected. |
| 324 | * In particular, any write request that would require pre-reading |
| 325 | * is put on a "delayed" queue until there are no stripes currently |
| 326 | * in a pre-read phase. Further, if the "delayed" queue is empty when |
| 327 | * a stripe is put on it then we "plug" the queue and do not process it |
| 328 | * until an unplug call is made. (the unplug_io_fn() is called). |
| 329 | * |
| 330 | * When preread is initiated on a stripe, we set PREREAD_ACTIVE and add |
| 331 | * it to the count of prereading stripes. |
| 332 | * When write is initiated, or the stripe refcnt == 0 (just in case) we |
| 333 | * clear the PREREAD_ACTIVE flag and decrement the count |
NeilBrown | b5c124a | 2006-10-03 01:15:45 -0700 | [diff] [blame] | 334 | * Whenever the 'handle' queue is empty and the device is not plugged, we |
| 335 | * move any strips from delayed to handle and clear the DELAYED flag and set |
| 336 | * PREREAD_ACTIVE. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 | * In stripe_handle, if we find pre-reading is necessary, we do it if |
| 338 | * PREREAD_ACTIVE is set, else we set DELAYED which will send it to the delayed queue. |
| 339 | * HANDLE gets cleared if stripe_handle leave nothing locked. |
| 340 | */ |
Christoph Hellwig | ef740c3 | 2009-03-31 14:27:03 +1100 | [diff] [blame] | 341 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | |
| 343 | struct disk_info { |
| 344 | mdk_rdev_t *rdev; |
| 345 | }; |
| 346 | |
| 347 | struct raid5_private_data { |
NeilBrown | fccddba | 2006-01-06 00:20:33 -0800 | [diff] [blame] | 348 | struct hlist_head *stripe_hashtbl; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | mddev_t *mddev; |
| 350 | struct disk_info *spare; |
Andre Noll | 09c9e5f | 2009-06-18 08:45:55 +1000 | [diff] [blame] | 351 | int chunk_sectors; |
| 352 | int level, algorithm; |
NeilBrown | 16a53ec | 2006-06-26 00:27:38 -0700 | [diff] [blame] | 353 | int max_degraded; |
NeilBrown | 02c2de8 | 2006-10-03 01:15:47 -0700 | [diff] [blame] | 354 | int raid_disks; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | int max_nr_stripes; |
| 356 | |
NeilBrown | fef9c61 | 2009-03-31 15:16:46 +1100 | [diff] [blame] | 357 | /* reshape_progress is the leading edge of a 'reshape' |
| 358 | * It has value MaxSector when no reshape is happening |
| 359 | * If delta_disks < 0, it is the last sector we started work on, |
| 360 | * else is it the next sector to work on. |
| 361 | */ |
| 362 | sector_t reshape_progress; |
| 363 | /* reshape_safe is the trailing edge of a reshape. We know that |
| 364 | * before (or after) this address, all reshape has completed. |
| 365 | */ |
| 366 | sector_t reshape_safe; |
NeilBrown | 7ecaa1e | 2006-03-27 01:18:08 -0800 | [diff] [blame] | 367 | int previous_raid_disks; |
Andre Noll | 09c9e5f | 2009-06-18 08:45:55 +1000 | [diff] [blame] | 368 | int prev_chunk_sectors; |
| 369 | int prev_algo; |
NeilBrown | 86b42c7 | 2009-03-31 15:19:03 +1100 | [diff] [blame] | 370 | short generation; /* increments with every reshape */ |
NeilBrown | c8f517c | 2009-03-31 15:28:40 +1100 | [diff] [blame] | 371 | unsigned long reshape_checkpoint; /* Time we last updated |
| 372 | * metadata */ |
NeilBrown | 7ecaa1e | 2006-03-27 01:18:08 -0800 | [diff] [blame] | 373 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 374 | struct list_head handle_list; /* stripes needing handling */ |
Dan Williams | 8b3e6cd | 2008-04-28 02:15:53 -0700 | [diff] [blame] | 375 | struct list_head hold_list; /* preread ready stripes */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 376 | struct list_head delayed_list; /* stripes that have plugged requests */ |
NeilBrown | 7262668 | 2005-09-09 16:23:54 -0700 | [diff] [blame] | 377 | struct list_head bitmap_list; /* stripes delaying awaiting bitmap update */ |
Raz Ben-Jehuda(caro) | 46031f9 | 2006-12-10 02:20:47 -0800 | [diff] [blame] | 378 | struct bio *retry_read_aligned; /* currently retrying aligned bios */ |
| 379 | struct bio *retry_read_aligned_list; /* aligned bios retry list */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 380 | atomic_t preread_active_stripes; /* stripes with scheduled io */ |
Raz Ben-Jehuda(caro) | 46031f9 | 2006-12-10 02:20:47 -0800 | [diff] [blame] | 381 | atomic_t active_aligned_reads; |
Dan Williams | 8b3e6cd | 2008-04-28 02:15:53 -0700 | [diff] [blame] | 382 | atomic_t pending_full_writes; /* full write backlog */ |
| 383 | int bypass_count; /* bypassed prereads */ |
| 384 | int bypass_threshold; /* preread nice */ |
| 385 | struct list_head *last_hold; /* detect hold_list promotions */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | |
NeilBrown | f670557 | 2006-03-27 01:18:11 -0800 | [diff] [blame] | 387 | atomic_t reshape_stripes; /* stripes with pending writes for reshape */ |
NeilBrown | ad01c9e | 2006-03-27 01:18:07 -0800 | [diff] [blame] | 388 | /* unfortunately we need two cache names as we temporarily have |
| 389 | * two caches. |
| 390 | */ |
| 391 | int active_name; |
NeilBrown | f4be6b4 | 2010-06-01 19:37:25 +1000 | [diff] [blame] | 392 | char cache_name[2][32]; |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 393 | struct kmem_cache *slab_cache; /* for allocating stripes */ |
NeilBrown | 7262668 | 2005-09-09 16:23:54 -0700 | [diff] [blame] | 394 | |
| 395 | int seq_flush, seq_write; |
| 396 | int quiesce; |
| 397 | |
| 398 | int fullsync; /* set to 1 if a full sync is needed, |
| 399 | * (fresh device added). |
| 400 | * Cleared when a sync completes. |
| 401 | */ |
NeilBrown | 2ac8740 | 2010-06-01 19:37:29 +1000 | [diff] [blame] | 402 | |
| 403 | struct plug_handle plug; |
| 404 | |
Dan Williams | 36d1c64 | 2009-07-14 11:48:22 -0700 | [diff] [blame] | 405 | /* per cpu variables */ |
| 406 | struct raid5_percpu { |
| 407 | struct page *spare_page; /* Used when checking P/Q in raid6 */ |
Dan Williams | d6f38f3 | 2009-07-14 11:50:52 -0700 | [diff] [blame] | 408 | void *scribble; /* space for constructing buffer |
| 409 | * lists and performing address |
| 410 | * conversions |
| 411 | */ |
Tejun Heo | a29d8b8 | 2010-02-02 14:39:15 +0900 | [diff] [blame] | 412 | } __percpu *percpu; |
Dan Williams | d6f38f3 | 2009-07-14 11:50:52 -0700 | [diff] [blame] | 413 | size_t scribble_len; /* size of scribble region must be |
| 414 | * associated with conf to handle |
| 415 | * cpu hotplug while reshaping |
| 416 | */ |
Dan Williams | 36d1c64 | 2009-07-14 11:48:22 -0700 | [diff] [blame] | 417 | #ifdef CONFIG_HOTPLUG_CPU |
| 418 | struct notifier_block cpu_notify; |
| 419 | #endif |
NeilBrown | ca65b73 | 2006-01-06 00:20:17 -0800 | [diff] [blame] | 420 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 421 | /* |
| 422 | * Free stripes pool |
| 423 | */ |
| 424 | atomic_t active_stripes; |
| 425 | struct list_head inactive_list; |
| 426 | wait_queue_head_t wait_for_stripe; |
| 427 | wait_queue_head_t wait_for_overlap; |
| 428 | int inactive_blocked; /* release of inactive stripes blocked, |
| 429 | * waiting for 25% to be free |
NeilBrown | ad01c9e | 2006-03-27 01:18:07 -0800 | [diff] [blame] | 430 | */ |
| 431 | int pool_size; /* number of disks in stripeheads in pool */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 432 | spinlock_t device_lock; |
NeilBrown | b55e6bf | 2006-03-27 01:18:06 -0800 | [diff] [blame] | 433 | struct disk_info *disks; |
NeilBrown | 91adb56 | 2009-03-31 14:39:39 +1100 | [diff] [blame] | 434 | |
| 435 | /* When taking over an array from a different personality, we store |
| 436 | * the new thread here until we fully activate the array. |
| 437 | */ |
| 438 | struct mdk_thread_s *thread; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 439 | }; |
| 440 | |
| 441 | typedef struct raid5_private_data raid5_conf_t; |
| 442 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | /* |
| 444 | * Our supported algorithms |
| 445 | */ |
NeilBrown | 99c0fb5 | 2009-03-31 14:39:38 +1100 | [diff] [blame] | 446 | #define ALGORITHM_LEFT_ASYMMETRIC 0 /* Rotating Parity N with Data Restart */ |
| 447 | #define ALGORITHM_RIGHT_ASYMMETRIC 1 /* Rotating Parity 0 with Data Restart */ |
| 448 | #define ALGORITHM_LEFT_SYMMETRIC 2 /* Rotating Parity N with Data Continuation */ |
| 449 | #define ALGORITHM_RIGHT_SYMMETRIC 3 /* Rotating Parity 0 with Data Continuation */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | |
NeilBrown | 99c0fb5 | 2009-03-31 14:39:38 +1100 | [diff] [blame] | 451 | /* Define non-rotating (raid4) algorithms. These allow |
| 452 | * conversion of raid4 to raid5. |
| 453 | */ |
| 454 | #define ALGORITHM_PARITY_0 4 /* P or P,Q are initial devices */ |
| 455 | #define ALGORITHM_PARITY_N 5 /* P or P,Q are final devices. */ |
| 456 | |
| 457 | /* DDF RAID6 layouts differ from md/raid6 layouts in two ways. |
| 458 | * Firstly, the exact positioning of the parity block is slightly |
| 459 | * different between the 'LEFT_*' modes of md and the "_N_*" modes |
| 460 | * of DDF. |
| 461 | * Secondly, or order of datablocks over which the Q syndrome is computed |
| 462 | * is different. |
| 463 | * Consequently we have different layouts for DDF/raid6 than md/raid6. |
| 464 | * These layouts are from the DDFv1.2 spec. |
| 465 | * Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but |
| 466 | * leaves RLQ=3 as 'Vendor Specific' |
| 467 | */ |
| 468 | |
| 469 | #define ALGORITHM_ROTATING_ZERO_RESTART 8 /* DDF PRL=6 RLQ=1 */ |
| 470 | #define ALGORITHM_ROTATING_N_RESTART 9 /* DDF PRL=6 RLQ=2 */ |
| 471 | #define ALGORITHM_ROTATING_N_CONTINUE 10 /*DDF PRL=6 RLQ=3 */ |
| 472 | |
| 473 | |
| 474 | /* For every RAID5 algorithm we define a RAID6 algorithm |
| 475 | * with exactly the same layout for data and parity, and |
| 476 | * with the Q block always on the last device (N-1). |
| 477 | * This allows trivial conversion from RAID5 to RAID6 |
| 478 | */ |
| 479 | #define ALGORITHM_LEFT_ASYMMETRIC_6 16 |
| 480 | #define ALGORITHM_RIGHT_ASYMMETRIC_6 17 |
| 481 | #define ALGORITHM_LEFT_SYMMETRIC_6 18 |
| 482 | #define ALGORITHM_RIGHT_SYMMETRIC_6 19 |
| 483 | #define ALGORITHM_PARITY_0_6 20 |
| 484 | #define ALGORITHM_PARITY_N_6 ALGORITHM_PARITY_N |
| 485 | |
| 486 | static inline int algorithm_valid_raid5(int layout) |
| 487 | { |
| 488 | return (layout >= 0) && |
| 489 | (layout <= 5); |
| 490 | } |
| 491 | static inline int algorithm_valid_raid6(int layout) |
| 492 | { |
| 493 | return (layout >= 0 && layout <= 5) |
| 494 | || |
NeilBrown | e4424fe | 2009-10-16 16:27:34 +1100 | [diff] [blame] | 495 | (layout >= 8 && layout <= 10) |
NeilBrown | 99c0fb5 | 2009-03-31 14:39:38 +1100 | [diff] [blame] | 496 | || |
| 497 | (layout >= 16 && layout <= 20); |
| 498 | } |
| 499 | |
| 500 | static inline int algorithm_is_DDF(int layout) |
| 501 | { |
| 502 | return layout >= 8 && layout <= 10; |
| 503 | } |
NeilBrown | 11d8a6e | 2010-07-26 11:57:07 +1000 | [diff] [blame] | 504 | |
| 505 | extern int md_raid5_congested(mddev_t *mddev, int bits); |
Jens Axboe | 7eaceac | 2011-03-10 08:52:07 +0100 | [diff] [blame] | 506 | extern void md_raid5_kick_device(raid5_conf_t *conf); |
NeilBrown | c41d4ac | 2010-06-01 19:37:24 +1000 | [diff] [blame] | 507 | extern int raid5_set_cache_size(mddev_t *mddev, int size); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 508 | #endif |