Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Some low level IO code, and hacks for various block layer limitations |
| 3 | * |
| 4 | * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com> |
| 5 | * Copyright 2012 Google, Inc. |
| 6 | */ |
| 7 | |
| 8 | #include "bcache.h" |
| 9 | #include "bset.h" |
| 10 | #include "debug.h" |
| 11 | |
Kent Overstreet | c37511b | 2013-04-26 15:39:55 -0700 | [diff] [blame] | 12 | #include <linux/blkdev.h> |
| 13 | |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 14 | /** |
| 15 | * bch_bio_split - split a bio |
| 16 | * @bio: bio to split |
| 17 | * @sectors: number of sectors to split from the front of @bio |
| 18 | * @gfp: gfp mask |
| 19 | * @bs: bio set to allocate from |
| 20 | * |
| 21 | * Allocates and returns a new bio which represents @sectors from the start of |
| 22 | * @bio, and updates @bio to represent the remaining sectors. |
| 23 | * |
| 24 | * If bio_sectors(@bio) was less than or equal to @sectors, returns @bio |
| 25 | * unchanged. |
| 26 | * |
| 27 | * The newly allocated bio will point to @bio's bi_io_vec, if the split was on a |
| 28 | * bvec boundry; it is the caller's responsibility to ensure that @bio is not |
| 29 | * freed before the split. |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 30 | */ |
| 31 | struct bio *bch_bio_split(struct bio *bio, int sectors, |
| 32 | gfp_t gfp, struct bio_set *bs) |
| 33 | { |
Kent Overstreet | 7988613 | 2013-11-23 17:19:00 -0800 | [diff] [blame] | 34 | unsigned vcnt = 0, nbytes = sectors << 9; |
| 35 | struct bio_vec bv; |
| 36 | struct bvec_iter iter; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 37 | struct bio *ret = NULL; |
| 38 | |
| 39 | BUG_ON(sectors <= 0); |
| 40 | |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 41 | if (sectors >= bio_sectors(bio)) |
| 42 | return bio; |
| 43 | |
| 44 | if (bio->bi_rw & REQ_DISCARD) { |
| 45 | ret = bio_alloc_bioset(gfp, 1, bs); |
Kumar Amit Mehta | 5c69412 | 2013-05-28 00:31:15 -0700 | [diff] [blame] | 46 | if (!ret) |
| 47 | return NULL; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 48 | goto out; |
| 49 | } |
| 50 | |
Kent Overstreet | 7988613 | 2013-11-23 17:19:00 -0800 | [diff] [blame] | 51 | bio_for_each_segment(bv, bio, iter) { |
| 52 | vcnt++; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 53 | |
Kent Overstreet | 7988613 | 2013-11-23 17:19:00 -0800 | [diff] [blame] | 54 | if (nbytes <= bv.bv_len) |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 55 | break; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 56 | |
Kent Overstreet | 7988613 | 2013-11-23 17:19:00 -0800 | [diff] [blame] | 57 | nbytes -= bv.bv_len; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 58 | } |
Kent Overstreet | 7988613 | 2013-11-23 17:19:00 -0800 | [diff] [blame] | 59 | |
| 60 | ret = bio_alloc_bioset(gfp, vcnt, bs); |
| 61 | if (!ret) |
| 62 | return NULL; |
| 63 | |
| 64 | bio_for_each_segment(bv, bio, iter) { |
| 65 | ret->bi_io_vec[ret->bi_vcnt++] = bv; |
| 66 | |
| 67 | if (ret->bi_vcnt == vcnt) |
| 68 | break; |
| 69 | } |
| 70 | |
| 71 | ret->bi_io_vec[ret->bi_vcnt - 1].bv_len = nbytes; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 72 | out: |
| 73 | ret->bi_bdev = bio->bi_bdev; |
Kent Overstreet | 4f024f3 | 2013-10-11 15:44:27 -0700 | [diff] [blame] | 74 | ret->bi_iter.bi_sector = bio->bi_iter.bi_sector; |
| 75 | ret->bi_iter.bi_size = sectors << 9; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 76 | ret->bi_rw = bio->bi_rw; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 77 | |
| 78 | if (bio_integrity(bio)) { |
| 79 | if (bio_integrity_clone(ret, bio, gfp)) { |
| 80 | bio_put(ret); |
| 81 | return NULL; |
| 82 | } |
| 83 | |
| 84 | bio_integrity_trim(ret, 0, bio_sectors(ret)); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 85 | } |
| 86 | |
Kent Overstreet | 7988613 | 2013-11-23 17:19:00 -0800 | [diff] [blame] | 87 | bio_advance(bio, ret->bi_iter.bi_size); |
| 88 | |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 89 | return ret; |
| 90 | } |
| 91 | |
| 92 | static unsigned bch_bio_max_sectors(struct bio *bio) |
| 93 | { |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 94 | struct request_queue *q = bdev_get_queue(bio->bi_bdev); |
Kent Overstreet | 458b76e | 2013-09-24 16:26:05 -0700 | [diff] [blame] | 95 | struct bio_vec bv; |
| 96 | struct bvec_iter iter; |
| 97 | unsigned ret = 0, seg = 0; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 98 | |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 99 | if (bio->bi_rw & REQ_DISCARD) |
Kent Overstreet | 458b76e | 2013-09-24 16:26:05 -0700 | [diff] [blame] | 100 | return min(bio_sectors(bio), q->limits.max_discard_sectors); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 101 | |
Kent Overstreet | 458b76e | 2013-09-24 16:26:05 -0700 | [diff] [blame] | 102 | bio_for_each_segment(bv, bio, iter) { |
| 103 | struct bvec_merge_data bvm = { |
| 104 | .bi_bdev = bio->bi_bdev, |
| 105 | .bi_sector = bio->bi_iter.bi_sector, |
| 106 | .bi_size = ret << 9, |
| 107 | .bi_rw = bio->bi_rw, |
| 108 | }; |
Kent Overstreet | 8e51e41 | 2013-06-06 18:15:57 -0700 | [diff] [blame] | 109 | |
Kent Overstreet | 458b76e | 2013-09-24 16:26:05 -0700 | [diff] [blame] | 110 | if (seg == min_t(unsigned, BIO_MAX_PAGES, |
| 111 | queue_max_segments(q))) |
| 112 | break; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 113 | |
Kent Overstreet | 458b76e | 2013-09-24 16:26:05 -0700 | [diff] [blame] | 114 | if (q->merge_bvec_fn && |
| 115 | q->merge_bvec_fn(q, &bvm, &bv) < (int) bv.bv_len) |
| 116 | break; |
Kent Overstreet | a09ded8 | 2013-04-22 14:44:24 -0700 | [diff] [blame] | 117 | |
Kent Overstreet | 458b76e | 2013-09-24 16:26:05 -0700 | [diff] [blame] | 118 | seg++; |
| 119 | ret += bv.bv_len >> 9; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 120 | } |
| 121 | |
| 122 | ret = min(ret, queue_max_sectors(q)); |
| 123 | |
| 124 | WARN_ON(!ret); |
Kent Overstreet | a4ad39b1 | 2013-08-07 14:24:32 -0700 | [diff] [blame] | 125 | ret = max_t(int, ret, bio_iovec(bio).bv_len >> 9); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 126 | |
| 127 | return ret; |
| 128 | } |
| 129 | |
| 130 | static void bch_bio_submit_split_done(struct closure *cl) |
| 131 | { |
| 132 | struct bio_split_hook *s = container_of(cl, struct bio_split_hook, cl); |
| 133 | |
| 134 | s->bio->bi_end_io = s->bi_end_io; |
| 135 | s->bio->bi_private = s->bi_private; |
Kent Overstreet | 196d38b | 2013-11-23 18:34:15 -0800 | [diff] [blame^] | 136 | bio_endio_nodec(s->bio, 0); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 137 | |
| 138 | closure_debug_destroy(&s->cl); |
| 139 | mempool_free(s, s->p->bio_split_hook); |
| 140 | } |
| 141 | |
| 142 | static void bch_bio_submit_split_endio(struct bio *bio, int error) |
| 143 | { |
| 144 | struct closure *cl = bio->bi_private; |
| 145 | struct bio_split_hook *s = container_of(cl, struct bio_split_hook, cl); |
| 146 | |
| 147 | if (error) |
| 148 | clear_bit(BIO_UPTODATE, &s->bio->bi_flags); |
| 149 | |
| 150 | bio_put(bio); |
| 151 | closure_put(cl); |
| 152 | } |
| 153 | |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 154 | void bch_generic_make_request(struct bio *bio, struct bio_split_pool *p) |
| 155 | { |
| 156 | struct bio_split_hook *s; |
Kent Overstreet | 8e51e41 | 2013-06-06 18:15:57 -0700 | [diff] [blame] | 157 | struct bio *n; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 158 | |
| 159 | if (!bio_has_data(bio) && !(bio->bi_rw & REQ_DISCARD)) |
| 160 | goto submit; |
| 161 | |
| 162 | if (bio_sectors(bio) <= bch_bio_max_sectors(bio)) |
| 163 | goto submit; |
| 164 | |
| 165 | s = mempool_alloc(p->bio_split_hook, GFP_NOIO); |
Kent Overstreet | 8e51e41 | 2013-06-06 18:15:57 -0700 | [diff] [blame] | 166 | closure_init(&s->cl, NULL); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 167 | |
| 168 | s->bio = bio; |
| 169 | s->p = p; |
| 170 | s->bi_end_io = bio->bi_end_io; |
| 171 | s->bi_private = bio->bi_private; |
| 172 | bio_get(bio); |
| 173 | |
Kent Overstreet | 8e51e41 | 2013-06-06 18:15:57 -0700 | [diff] [blame] | 174 | do { |
| 175 | n = bch_bio_split(bio, bch_bio_max_sectors(bio), |
| 176 | GFP_NOIO, s->p->bio_split); |
| 177 | |
| 178 | n->bi_end_io = bch_bio_submit_split_endio; |
| 179 | n->bi_private = &s->cl; |
| 180 | |
| 181 | closure_get(&s->cl); |
Kent Overstreet | e90abc8 | 2013-08-07 14:31:42 -0700 | [diff] [blame] | 182 | generic_make_request(n); |
Kent Overstreet | 8e51e41 | 2013-06-06 18:15:57 -0700 | [diff] [blame] | 183 | } while (n != bio); |
| 184 | |
| 185 | continue_at(&s->cl, bch_bio_submit_split_done, NULL); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 186 | submit: |
Kent Overstreet | e90abc8 | 2013-08-07 14:31:42 -0700 | [diff] [blame] | 187 | generic_make_request(bio); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 188 | } |
| 189 | |
| 190 | /* Bios with headers */ |
| 191 | |
| 192 | void bch_bbio_free(struct bio *bio, struct cache_set *c) |
| 193 | { |
| 194 | struct bbio *b = container_of(bio, struct bbio, bio); |
| 195 | mempool_free(b, c->bio_meta); |
| 196 | } |
| 197 | |
| 198 | struct bio *bch_bbio_alloc(struct cache_set *c) |
| 199 | { |
| 200 | struct bbio *b = mempool_alloc(c->bio_meta, GFP_NOIO); |
| 201 | struct bio *bio = &b->bio; |
| 202 | |
| 203 | bio_init(bio); |
| 204 | bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET; |
| 205 | bio->bi_max_vecs = bucket_pages(c); |
| 206 | bio->bi_io_vec = bio->bi_inline_vecs; |
| 207 | |
| 208 | return bio; |
| 209 | } |
| 210 | |
| 211 | void __bch_submit_bbio(struct bio *bio, struct cache_set *c) |
| 212 | { |
| 213 | struct bbio *b = container_of(bio, struct bbio, bio); |
| 214 | |
Kent Overstreet | 4f024f3 | 2013-10-11 15:44:27 -0700 | [diff] [blame] | 215 | bio->bi_iter.bi_sector = PTR_OFFSET(&b->key, 0); |
| 216 | bio->bi_bdev = PTR_CACHE(c, &b->key, 0)->bdev; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 217 | |
| 218 | b->submit_time_us = local_clock_us(); |
| 219 | closure_bio_submit(bio, bio->bi_private, PTR_CACHE(c, &b->key, 0)); |
| 220 | } |
| 221 | |
| 222 | void bch_submit_bbio(struct bio *bio, struct cache_set *c, |
| 223 | struct bkey *k, unsigned ptr) |
| 224 | { |
| 225 | struct bbio *b = container_of(bio, struct bbio, bio); |
| 226 | bch_bkey_copy_single_ptr(&b->key, k, ptr); |
| 227 | __bch_submit_bbio(bio, c); |
| 228 | } |
| 229 | |
| 230 | /* IO errors */ |
| 231 | |
| 232 | void bch_count_io_errors(struct cache *ca, int error, const char *m) |
| 233 | { |
| 234 | /* |
| 235 | * The halflife of an error is: |
| 236 | * log2(1/2)/log2(127/128) * refresh ~= 88 * refresh |
| 237 | */ |
| 238 | |
| 239 | if (ca->set->error_decay) { |
| 240 | unsigned count = atomic_inc_return(&ca->io_count); |
| 241 | |
| 242 | while (count > ca->set->error_decay) { |
| 243 | unsigned errors; |
| 244 | unsigned old = count; |
| 245 | unsigned new = count - ca->set->error_decay; |
| 246 | |
| 247 | /* |
| 248 | * First we subtract refresh from count; each time we |
| 249 | * succesfully do so, we rescale the errors once: |
| 250 | */ |
| 251 | |
| 252 | count = atomic_cmpxchg(&ca->io_count, old, new); |
| 253 | |
| 254 | if (count == old) { |
| 255 | count = new; |
| 256 | |
| 257 | errors = atomic_read(&ca->io_errors); |
| 258 | do { |
| 259 | old = errors; |
| 260 | new = ((uint64_t) errors * 127) / 128; |
| 261 | errors = atomic_cmpxchg(&ca->io_errors, |
| 262 | old, new); |
| 263 | } while (old != errors); |
| 264 | } |
| 265 | } |
| 266 | } |
| 267 | |
| 268 | if (error) { |
| 269 | char buf[BDEVNAME_SIZE]; |
| 270 | unsigned errors = atomic_add_return(1 << IO_ERROR_SHIFT, |
| 271 | &ca->io_errors); |
| 272 | errors >>= IO_ERROR_SHIFT; |
| 273 | |
| 274 | if (errors < ca->set->error_limit) |
| 275 | pr_err("%s: IO error on %s, recovering", |
| 276 | bdevname(ca->bdev, buf), m); |
| 277 | else |
| 278 | bch_cache_set_error(ca->set, |
| 279 | "%s: too many IO errors %s", |
| 280 | bdevname(ca->bdev, buf), m); |
| 281 | } |
| 282 | } |
| 283 | |
| 284 | void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio, |
| 285 | int error, const char *m) |
| 286 | { |
| 287 | struct bbio *b = container_of(bio, struct bbio, bio); |
| 288 | struct cache *ca = PTR_CACHE(c, &b->key, 0); |
| 289 | |
| 290 | unsigned threshold = bio->bi_rw & REQ_WRITE |
| 291 | ? c->congested_write_threshold_us |
| 292 | : c->congested_read_threshold_us; |
| 293 | |
| 294 | if (threshold) { |
| 295 | unsigned t = local_clock_us(); |
| 296 | |
| 297 | int us = t - b->submit_time_us; |
| 298 | int congested = atomic_read(&c->congested); |
| 299 | |
| 300 | if (us > (int) threshold) { |
| 301 | int ms = us / 1024; |
| 302 | c->congested_last_us = t; |
| 303 | |
| 304 | ms = min(ms, CONGESTED_MAX + congested); |
| 305 | atomic_sub(ms, &c->congested); |
| 306 | } else if (congested < 0) |
| 307 | atomic_inc(&c->congested); |
| 308 | } |
| 309 | |
| 310 | bch_count_io_errors(ca, error, m); |
| 311 | } |
| 312 | |
| 313 | void bch_bbio_endio(struct cache_set *c, struct bio *bio, |
| 314 | int error, const char *m) |
| 315 | { |
| 316 | struct closure *cl = bio->bi_private; |
| 317 | |
| 318 | bch_bbio_count_io_errors(c, bio, error, m); |
| 319 | bio_put(bio); |
| 320 | closure_put(cl); |
| 321 | } |