| 1 | /* |
| 2 | * Copyright (c) 2000-2006 Silicon Graphics, Inc. |
| 3 | * All Rights Reserved. |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU General Public License as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * This program is distributed in the hope that it would be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write the Free Software Foundation, |
| 16 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 17 | */ |
| 18 | #include "xfs.h" |
| 19 | #include <linux/stddef.h> |
| 20 | #include <linux/errno.h> |
| 21 | #include <linux/gfp.h> |
| 22 | #include <linux/pagemap.h> |
| 23 | #include <linux/init.h> |
| 24 | #include <linux/vmalloc.h> |
| 25 | #include <linux/bio.h> |
| 26 | #include <linux/sysctl.h> |
| 27 | #include <linux/proc_fs.h> |
| 28 | #include <linux/workqueue.h> |
| 29 | #include <linux/percpu.h> |
| 30 | #include <linux/blkdev.h> |
| 31 | #include <linux/hash.h> |
| 32 | #include <linux/kthread.h> |
| 33 | #include <linux/migrate.h> |
| 34 | #include <linux/backing-dev.h> |
| 35 | #include <linux/freezer.h> |
| 36 | |
| 37 | #include "xfs_format.h" |
| 38 | #include "xfs_log_format.h" |
| 39 | #include "xfs_trans_resv.h" |
| 40 | #include "xfs_sb.h" |
| 41 | #include "xfs_mount.h" |
| 42 | #include "xfs_trace.h" |
| 43 | #include "xfs_log.h" |
| 44 | |
| 45 | static kmem_zone_t *xfs_buf_zone; |
| 46 | |
| 47 | #ifdef XFS_BUF_LOCK_TRACKING |
| 48 | # define XB_SET_OWNER(bp) ((bp)->b_last_holder = current->pid) |
| 49 | # define XB_CLEAR_OWNER(bp) ((bp)->b_last_holder = -1) |
| 50 | # define XB_GET_OWNER(bp) ((bp)->b_last_holder) |
| 51 | #else |
| 52 | # define XB_SET_OWNER(bp) do { } while (0) |
| 53 | # define XB_CLEAR_OWNER(bp) do { } while (0) |
| 54 | # define XB_GET_OWNER(bp) do { } while (0) |
| 55 | #endif |
| 56 | |
| 57 | #define xb_to_gfp(flags) \ |
| 58 | ((((flags) & XBF_READ_AHEAD) ? __GFP_NORETRY : GFP_NOFS) | __GFP_NOWARN) |
| 59 | |
| 60 | |
| 61 | static inline int |
| 62 | xfs_buf_is_vmapped( |
| 63 | struct xfs_buf *bp) |
| 64 | { |
| 65 | /* |
| 66 | * Return true if the buffer is vmapped. |
| 67 | * |
| 68 | * b_addr is null if the buffer is not mapped, but the code is clever |
| 69 | * enough to know it doesn't have to map a single page, so the check has |
| 70 | * to be both for b_addr and bp->b_page_count > 1. |
| 71 | */ |
| 72 | return bp->b_addr && bp->b_page_count > 1; |
| 73 | } |
| 74 | |
| 75 | static inline int |
| 76 | xfs_buf_vmap_len( |
| 77 | struct xfs_buf *bp) |
| 78 | { |
| 79 | return (bp->b_page_count * PAGE_SIZE) - bp->b_offset; |
| 80 | } |
| 81 | |
| 82 | /* |
| 83 | * When we mark a buffer stale, we remove the buffer from the LRU and clear the |
| 84 | * b_lru_ref count so that the buffer is freed immediately when the buffer |
| 85 | * reference count falls to zero. If the buffer is already on the LRU, we need |
| 86 | * to remove the reference that LRU holds on the buffer. |
| 87 | * |
| 88 | * This prevents build-up of stale buffers on the LRU. |
| 89 | */ |
| 90 | void |
| 91 | xfs_buf_stale( |
| 92 | struct xfs_buf *bp) |
| 93 | { |
| 94 | ASSERT(xfs_buf_islocked(bp)); |
| 95 | |
| 96 | bp->b_flags |= XBF_STALE; |
| 97 | |
| 98 | /* |
| 99 | * Clear the delwri status so that a delwri queue walker will not |
| 100 | * flush this buffer to disk now that it is stale. The delwri queue has |
| 101 | * a reference to the buffer, so this is safe to do. |
| 102 | */ |
| 103 | bp->b_flags &= ~_XBF_DELWRI_Q; |
| 104 | |
| 105 | spin_lock(&bp->b_lock); |
| 106 | atomic_set(&bp->b_lru_ref, 0); |
| 107 | if (!(bp->b_state & XFS_BSTATE_DISPOSE) && |
| 108 | (list_lru_del(&bp->b_target->bt_lru, &bp->b_lru))) |
| 109 | atomic_dec(&bp->b_hold); |
| 110 | |
| 111 | ASSERT(atomic_read(&bp->b_hold) >= 1); |
| 112 | spin_unlock(&bp->b_lock); |
| 113 | } |
| 114 | |
| 115 | static int |
| 116 | xfs_buf_get_maps( |
| 117 | struct xfs_buf *bp, |
| 118 | int map_count) |
| 119 | { |
| 120 | ASSERT(bp->b_maps == NULL); |
| 121 | bp->b_map_count = map_count; |
| 122 | |
| 123 | if (map_count == 1) { |
| 124 | bp->b_maps = &bp->__b_map; |
| 125 | return 0; |
| 126 | } |
| 127 | |
| 128 | bp->b_maps = kmem_zalloc(map_count * sizeof(struct xfs_buf_map), |
| 129 | KM_NOFS); |
| 130 | if (!bp->b_maps) |
| 131 | return -ENOMEM; |
| 132 | return 0; |
| 133 | } |
| 134 | |
| 135 | /* |
| 136 | * Frees b_pages if it was allocated. |
| 137 | */ |
| 138 | static void |
| 139 | xfs_buf_free_maps( |
| 140 | struct xfs_buf *bp) |
| 141 | { |
| 142 | if (bp->b_maps != &bp->__b_map) { |
| 143 | kmem_free(bp->b_maps); |
| 144 | bp->b_maps = NULL; |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | struct xfs_buf * |
| 149 | _xfs_buf_alloc( |
| 150 | struct xfs_buftarg *target, |
| 151 | struct xfs_buf_map *map, |
| 152 | int nmaps, |
| 153 | xfs_buf_flags_t flags) |
| 154 | { |
| 155 | struct xfs_buf *bp; |
| 156 | int error; |
| 157 | int i; |
| 158 | |
| 159 | bp = kmem_zone_zalloc(xfs_buf_zone, KM_NOFS); |
| 160 | if (unlikely(!bp)) |
| 161 | return NULL; |
| 162 | |
| 163 | /* |
| 164 | * We don't want certain flags to appear in b_flags unless they are |
| 165 | * specifically set by later operations on the buffer. |
| 166 | */ |
| 167 | flags &= ~(XBF_UNMAPPED | XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD); |
| 168 | |
| 169 | atomic_set(&bp->b_hold, 1); |
| 170 | atomic_set(&bp->b_lru_ref, 1); |
| 171 | init_completion(&bp->b_iowait); |
| 172 | INIT_LIST_HEAD(&bp->b_lru); |
| 173 | INIT_LIST_HEAD(&bp->b_list); |
| 174 | RB_CLEAR_NODE(&bp->b_rbnode); |
| 175 | sema_init(&bp->b_sema, 0); /* held, no waiters */ |
| 176 | spin_lock_init(&bp->b_lock); |
| 177 | XB_SET_OWNER(bp); |
| 178 | bp->b_target = target; |
| 179 | bp->b_flags = flags; |
| 180 | |
| 181 | /* |
| 182 | * Set length and io_length to the same value initially. |
| 183 | * I/O routines should use io_length, which will be the same in |
| 184 | * most cases but may be reset (e.g. XFS recovery). |
| 185 | */ |
| 186 | error = xfs_buf_get_maps(bp, nmaps); |
| 187 | if (error) { |
| 188 | kmem_zone_free(xfs_buf_zone, bp); |
| 189 | return NULL; |
| 190 | } |
| 191 | |
| 192 | bp->b_bn = map[0].bm_bn; |
| 193 | bp->b_length = 0; |
| 194 | for (i = 0; i < nmaps; i++) { |
| 195 | bp->b_maps[i].bm_bn = map[i].bm_bn; |
| 196 | bp->b_maps[i].bm_len = map[i].bm_len; |
| 197 | bp->b_length += map[i].bm_len; |
| 198 | } |
| 199 | bp->b_io_length = bp->b_length; |
| 200 | |
| 201 | atomic_set(&bp->b_pin_count, 0); |
| 202 | init_waitqueue_head(&bp->b_waiters); |
| 203 | |
| 204 | XFS_STATS_INC(target->bt_mount, xb_create); |
| 205 | trace_xfs_buf_init(bp, _RET_IP_); |
| 206 | |
| 207 | return bp; |
| 208 | } |
| 209 | |
| 210 | /* |
| 211 | * Allocate a page array capable of holding a specified number |
| 212 | * of pages, and point the page buf at it. |
| 213 | */ |
| 214 | STATIC int |
| 215 | _xfs_buf_get_pages( |
| 216 | xfs_buf_t *bp, |
| 217 | int page_count) |
| 218 | { |
| 219 | /* Make sure that we have a page list */ |
| 220 | if (bp->b_pages == NULL) { |
| 221 | bp->b_page_count = page_count; |
| 222 | if (page_count <= XB_PAGES) { |
| 223 | bp->b_pages = bp->b_page_array; |
| 224 | } else { |
| 225 | bp->b_pages = kmem_alloc(sizeof(struct page *) * |
| 226 | page_count, KM_NOFS); |
| 227 | if (bp->b_pages == NULL) |
| 228 | return -ENOMEM; |
| 229 | } |
| 230 | memset(bp->b_pages, 0, sizeof(struct page *) * page_count); |
| 231 | } |
| 232 | return 0; |
| 233 | } |
| 234 | |
| 235 | /* |
| 236 | * Frees b_pages if it was allocated. |
| 237 | */ |
| 238 | STATIC void |
| 239 | _xfs_buf_free_pages( |
| 240 | xfs_buf_t *bp) |
| 241 | { |
| 242 | if (bp->b_pages != bp->b_page_array) { |
| 243 | kmem_free(bp->b_pages); |
| 244 | bp->b_pages = NULL; |
| 245 | } |
| 246 | } |
| 247 | |
| 248 | /* |
| 249 | * Releases the specified buffer. |
| 250 | * |
| 251 | * The modification state of any associated pages is left unchanged. |
| 252 | * The buffer must not be on any hash - use xfs_buf_rele instead for |
| 253 | * hashed and refcounted buffers |
| 254 | */ |
| 255 | void |
| 256 | xfs_buf_free( |
| 257 | xfs_buf_t *bp) |
| 258 | { |
| 259 | trace_xfs_buf_free(bp, _RET_IP_); |
| 260 | |
| 261 | ASSERT(list_empty(&bp->b_lru)); |
| 262 | |
| 263 | if (bp->b_flags & _XBF_PAGES) { |
| 264 | uint i; |
| 265 | |
| 266 | if (xfs_buf_is_vmapped(bp)) |
| 267 | vm_unmap_ram(bp->b_addr - bp->b_offset, |
| 268 | bp->b_page_count); |
| 269 | |
| 270 | for (i = 0; i < bp->b_page_count; i++) { |
| 271 | struct page *page = bp->b_pages[i]; |
| 272 | |
| 273 | __free_page(page); |
| 274 | } |
| 275 | } else if (bp->b_flags & _XBF_KMEM) |
| 276 | kmem_free(bp->b_addr); |
| 277 | _xfs_buf_free_pages(bp); |
| 278 | xfs_buf_free_maps(bp); |
| 279 | kmem_zone_free(xfs_buf_zone, bp); |
| 280 | } |
| 281 | |
| 282 | /* |
| 283 | * Allocates all the pages for buffer in question and builds it's page list. |
| 284 | */ |
| 285 | STATIC int |
| 286 | xfs_buf_allocate_memory( |
| 287 | xfs_buf_t *bp, |
| 288 | uint flags) |
| 289 | { |
| 290 | size_t size; |
| 291 | size_t nbytes, offset; |
| 292 | gfp_t gfp_mask = xb_to_gfp(flags); |
| 293 | unsigned short page_count, i; |
| 294 | xfs_off_t start, end; |
| 295 | int error; |
| 296 | |
| 297 | /* |
| 298 | * for buffers that are contained within a single page, just allocate |
| 299 | * the memory from the heap - there's no need for the complexity of |
| 300 | * page arrays to keep allocation down to order 0. |
| 301 | */ |
| 302 | size = BBTOB(bp->b_length); |
| 303 | if (size < PAGE_SIZE) { |
| 304 | bp->b_addr = kmem_alloc(size, KM_NOFS); |
| 305 | if (!bp->b_addr) { |
| 306 | /* low memory - use alloc_page loop instead */ |
| 307 | goto use_alloc_page; |
| 308 | } |
| 309 | |
| 310 | if (((unsigned long)(bp->b_addr + size - 1) & PAGE_MASK) != |
| 311 | ((unsigned long)bp->b_addr & PAGE_MASK)) { |
| 312 | /* b_addr spans two pages - use alloc_page instead */ |
| 313 | kmem_free(bp->b_addr); |
| 314 | bp->b_addr = NULL; |
| 315 | goto use_alloc_page; |
| 316 | } |
| 317 | bp->b_offset = offset_in_page(bp->b_addr); |
| 318 | bp->b_pages = bp->b_page_array; |
| 319 | bp->b_pages[0] = virt_to_page(bp->b_addr); |
| 320 | bp->b_page_count = 1; |
| 321 | bp->b_flags |= _XBF_KMEM; |
| 322 | return 0; |
| 323 | } |
| 324 | |
| 325 | use_alloc_page: |
| 326 | start = BBTOB(bp->b_maps[0].bm_bn) >> PAGE_SHIFT; |
| 327 | end = (BBTOB(bp->b_maps[0].bm_bn + bp->b_length) + PAGE_SIZE - 1) |
| 328 | >> PAGE_SHIFT; |
| 329 | page_count = end - start; |
| 330 | error = _xfs_buf_get_pages(bp, page_count); |
| 331 | if (unlikely(error)) |
| 332 | return error; |
| 333 | |
| 334 | offset = bp->b_offset; |
| 335 | bp->b_flags |= _XBF_PAGES; |
| 336 | |
| 337 | for (i = 0; i < bp->b_page_count; i++) { |
| 338 | struct page *page; |
| 339 | uint retries = 0; |
| 340 | retry: |
| 341 | page = alloc_page(gfp_mask); |
| 342 | if (unlikely(page == NULL)) { |
| 343 | if (flags & XBF_READ_AHEAD) { |
| 344 | bp->b_page_count = i; |
| 345 | error = -ENOMEM; |
| 346 | goto out_free_pages; |
| 347 | } |
| 348 | |
| 349 | /* |
| 350 | * This could deadlock. |
| 351 | * |
| 352 | * But until all the XFS lowlevel code is revamped to |
| 353 | * handle buffer allocation failures we can't do much. |
| 354 | */ |
| 355 | if (!(++retries % 100)) |
| 356 | xfs_err(NULL, |
| 357 | "%s(%u) possible memory allocation deadlock in %s (mode:0x%x)", |
| 358 | current->comm, current->pid, |
| 359 | __func__, gfp_mask); |
| 360 | |
| 361 | XFS_STATS_INC(bp->b_target->bt_mount, xb_page_retries); |
| 362 | congestion_wait(BLK_RW_ASYNC, HZ/50); |
| 363 | goto retry; |
| 364 | } |
| 365 | |
| 366 | XFS_STATS_INC(bp->b_target->bt_mount, xb_page_found); |
| 367 | |
| 368 | nbytes = min_t(size_t, size, PAGE_SIZE - offset); |
| 369 | size -= nbytes; |
| 370 | bp->b_pages[i] = page; |
| 371 | offset = 0; |
| 372 | } |
| 373 | return 0; |
| 374 | |
| 375 | out_free_pages: |
| 376 | for (i = 0; i < bp->b_page_count; i++) |
| 377 | __free_page(bp->b_pages[i]); |
| 378 | return error; |
| 379 | } |
| 380 | |
| 381 | /* |
| 382 | * Map buffer into kernel address-space if necessary. |
| 383 | */ |
| 384 | STATIC int |
| 385 | _xfs_buf_map_pages( |
| 386 | xfs_buf_t *bp, |
| 387 | uint flags) |
| 388 | { |
| 389 | ASSERT(bp->b_flags & _XBF_PAGES); |
| 390 | if (bp->b_page_count == 1) { |
| 391 | /* A single page buffer is always mappable */ |
| 392 | bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset; |
| 393 | } else if (flags & XBF_UNMAPPED) { |
| 394 | bp->b_addr = NULL; |
| 395 | } else { |
| 396 | int retried = 0; |
| 397 | unsigned noio_flag; |
| 398 | |
| 399 | /* |
| 400 | * vm_map_ram() will allocate auxillary structures (e.g. |
| 401 | * pagetables) with GFP_KERNEL, yet we are likely to be under |
| 402 | * GFP_NOFS context here. Hence we need to tell memory reclaim |
| 403 | * that we are in such a context via PF_MEMALLOC_NOIO to prevent |
| 404 | * memory reclaim re-entering the filesystem here and |
| 405 | * potentially deadlocking. |
| 406 | */ |
| 407 | noio_flag = memalloc_noio_save(); |
| 408 | do { |
| 409 | bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count, |
| 410 | -1, PAGE_KERNEL); |
| 411 | if (bp->b_addr) |
| 412 | break; |
| 413 | vm_unmap_aliases(); |
| 414 | } while (retried++ <= 1); |
| 415 | memalloc_noio_restore(noio_flag); |
| 416 | |
| 417 | if (!bp->b_addr) |
| 418 | return -ENOMEM; |
| 419 | bp->b_addr += bp->b_offset; |
| 420 | } |
| 421 | |
| 422 | return 0; |
| 423 | } |
| 424 | |
| 425 | /* |
| 426 | * Finding and Reading Buffers |
| 427 | */ |
| 428 | |
| 429 | /* |
| 430 | * Look up, and creates if absent, a lockable buffer for |
| 431 | * a given range of an inode. The buffer is returned |
| 432 | * locked. No I/O is implied by this call. |
| 433 | */ |
| 434 | xfs_buf_t * |
| 435 | _xfs_buf_find( |
| 436 | struct xfs_buftarg *btp, |
| 437 | struct xfs_buf_map *map, |
| 438 | int nmaps, |
| 439 | xfs_buf_flags_t flags, |
| 440 | xfs_buf_t *new_bp) |
| 441 | { |
| 442 | struct xfs_perag *pag; |
| 443 | struct rb_node **rbp; |
| 444 | struct rb_node *parent; |
| 445 | xfs_buf_t *bp; |
| 446 | xfs_daddr_t blkno = map[0].bm_bn; |
| 447 | xfs_daddr_t eofs; |
| 448 | int numblks = 0; |
| 449 | int i; |
| 450 | |
| 451 | for (i = 0; i < nmaps; i++) |
| 452 | numblks += map[i].bm_len; |
| 453 | |
| 454 | /* Check for IOs smaller than the sector size / not sector aligned */ |
| 455 | ASSERT(!(BBTOB(numblks) < btp->bt_meta_sectorsize)); |
| 456 | ASSERT(!(BBTOB(blkno) & (xfs_off_t)btp->bt_meta_sectormask)); |
| 457 | |
| 458 | /* |
| 459 | * Corrupted block numbers can get through to here, unfortunately, so we |
| 460 | * have to check that the buffer falls within the filesystem bounds. |
| 461 | */ |
| 462 | eofs = XFS_FSB_TO_BB(btp->bt_mount, btp->bt_mount->m_sb.sb_dblocks); |
| 463 | if (blkno < 0 || blkno >= eofs) { |
| 464 | /* |
| 465 | * XXX (dgc): we should really be returning -EFSCORRUPTED here, |
| 466 | * but none of the higher level infrastructure supports |
| 467 | * returning a specific error on buffer lookup failures. |
| 468 | */ |
| 469 | xfs_alert(btp->bt_mount, |
| 470 | "%s: Block out of range: block 0x%llx, EOFS 0x%llx ", |
| 471 | __func__, blkno, eofs); |
| 472 | WARN_ON(1); |
| 473 | return NULL; |
| 474 | } |
| 475 | |
| 476 | /* get tree root */ |
| 477 | pag = xfs_perag_get(btp->bt_mount, |
| 478 | xfs_daddr_to_agno(btp->bt_mount, blkno)); |
| 479 | |
| 480 | /* walk tree */ |
| 481 | spin_lock(&pag->pag_buf_lock); |
| 482 | rbp = &pag->pag_buf_tree.rb_node; |
| 483 | parent = NULL; |
| 484 | bp = NULL; |
| 485 | while (*rbp) { |
| 486 | parent = *rbp; |
| 487 | bp = rb_entry(parent, struct xfs_buf, b_rbnode); |
| 488 | |
| 489 | if (blkno < bp->b_bn) |
| 490 | rbp = &(*rbp)->rb_left; |
| 491 | else if (blkno > bp->b_bn) |
| 492 | rbp = &(*rbp)->rb_right; |
| 493 | else { |
| 494 | /* |
| 495 | * found a block number match. If the range doesn't |
| 496 | * match, the only way this is allowed is if the buffer |
| 497 | * in the cache is stale and the transaction that made |
| 498 | * it stale has not yet committed. i.e. we are |
| 499 | * reallocating a busy extent. Skip this buffer and |
| 500 | * continue searching to the right for an exact match. |
| 501 | */ |
| 502 | if (bp->b_length != numblks) { |
| 503 | ASSERT(bp->b_flags & XBF_STALE); |
| 504 | rbp = &(*rbp)->rb_right; |
| 505 | continue; |
| 506 | } |
| 507 | atomic_inc(&bp->b_hold); |
| 508 | goto found; |
| 509 | } |
| 510 | } |
| 511 | |
| 512 | /* No match found */ |
| 513 | if (new_bp) { |
| 514 | rb_link_node(&new_bp->b_rbnode, parent, rbp); |
| 515 | rb_insert_color(&new_bp->b_rbnode, &pag->pag_buf_tree); |
| 516 | /* the buffer keeps the perag reference until it is freed */ |
| 517 | new_bp->b_pag = pag; |
| 518 | spin_unlock(&pag->pag_buf_lock); |
| 519 | } else { |
| 520 | XFS_STATS_INC(btp->bt_mount, xb_miss_locked); |
| 521 | spin_unlock(&pag->pag_buf_lock); |
| 522 | xfs_perag_put(pag); |
| 523 | } |
| 524 | return new_bp; |
| 525 | |
| 526 | found: |
| 527 | spin_unlock(&pag->pag_buf_lock); |
| 528 | xfs_perag_put(pag); |
| 529 | |
| 530 | if (!xfs_buf_trylock(bp)) { |
| 531 | if (flags & XBF_TRYLOCK) { |
| 532 | xfs_buf_rele(bp); |
| 533 | XFS_STATS_INC(btp->bt_mount, xb_busy_locked); |
| 534 | return NULL; |
| 535 | } |
| 536 | xfs_buf_lock(bp); |
| 537 | XFS_STATS_INC(btp->bt_mount, xb_get_locked_waited); |
| 538 | } |
| 539 | |
| 540 | /* |
| 541 | * if the buffer is stale, clear all the external state associated with |
| 542 | * it. We need to keep flags such as how we allocated the buffer memory |
| 543 | * intact here. |
| 544 | */ |
| 545 | if (bp->b_flags & XBF_STALE) { |
| 546 | ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0); |
| 547 | ASSERT(bp->b_iodone == NULL); |
| 548 | bp->b_flags &= _XBF_KMEM | _XBF_PAGES; |
| 549 | bp->b_ops = NULL; |
| 550 | } |
| 551 | |
| 552 | trace_xfs_buf_find(bp, flags, _RET_IP_); |
| 553 | XFS_STATS_INC(btp->bt_mount, xb_get_locked); |
| 554 | return bp; |
| 555 | } |
| 556 | |
| 557 | /* |
| 558 | * Assembles a buffer covering the specified range. The code is optimised for |
| 559 | * cache hits, as metadata intensive workloads will see 3 orders of magnitude |
| 560 | * more hits than misses. |
| 561 | */ |
| 562 | struct xfs_buf * |
| 563 | xfs_buf_get_map( |
| 564 | struct xfs_buftarg *target, |
| 565 | struct xfs_buf_map *map, |
| 566 | int nmaps, |
| 567 | xfs_buf_flags_t flags) |
| 568 | { |
| 569 | struct xfs_buf *bp; |
| 570 | struct xfs_buf *new_bp; |
| 571 | int error = 0; |
| 572 | |
| 573 | bp = _xfs_buf_find(target, map, nmaps, flags, NULL); |
| 574 | if (likely(bp)) |
| 575 | goto found; |
| 576 | |
| 577 | new_bp = _xfs_buf_alloc(target, map, nmaps, flags); |
| 578 | if (unlikely(!new_bp)) |
| 579 | return NULL; |
| 580 | |
| 581 | error = xfs_buf_allocate_memory(new_bp, flags); |
| 582 | if (error) { |
| 583 | xfs_buf_free(new_bp); |
| 584 | return NULL; |
| 585 | } |
| 586 | |
| 587 | bp = _xfs_buf_find(target, map, nmaps, flags, new_bp); |
| 588 | if (!bp) { |
| 589 | xfs_buf_free(new_bp); |
| 590 | return NULL; |
| 591 | } |
| 592 | |
| 593 | if (bp != new_bp) |
| 594 | xfs_buf_free(new_bp); |
| 595 | |
| 596 | found: |
| 597 | if (!bp->b_addr) { |
| 598 | error = _xfs_buf_map_pages(bp, flags); |
| 599 | if (unlikely(error)) { |
| 600 | xfs_warn(target->bt_mount, |
| 601 | "%s: failed to map pagesn", __func__); |
| 602 | xfs_buf_relse(bp); |
| 603 | return NULL; |
| 604 | } |
| 605 | } |
| 606 | |
| 607 | /* |
| 608 | * Clear b_error if this is a lookup from a caller that doesn't expect |
| 609 | * valid data to be found in the buffer. |
| 610 | */ |
| 611 | if (!(flags & XBF_READ)) |
| 612 | xfs_buf_ioerror(bp, 0); |
| 613 | |
| 614 | XFS_STATS_INC(target->bt_mount, xb_get); |
| 615 | trace_xfs_buf_get(bp, flags, _RET_IP_); |
| 616 | return bp; |
| 617 | } |
| 618 | |
| 619 | STATIC int |
| 620 | _xfs_buf_read( |
| 621 | xfs_buf_t *bp, |
| 622 | xfs_buf_flags_t flags) |
| 623 | { |
| 624 | ASSERT(!(flags & XBF_WRITE)); |
| 625 | ASSERT(bp->b_maps[0].bm_bn != XFS_BUF_DADDR_NULL); |
| 626 | |
| 627 | bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD); |
| 628 | bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD); |
| 629 | |
| 630 | if (flags & XBF_ASYNC) { |
| 631 | xfs_buf_submit(bp); |
| 632 | return 0; |
| 633 | } |
| 634 | return xfs_buf_submit_wait(bp); |
| 635 | } |
| 636 | |
| 637 | xfs_buf_t * |
| 638 | xfs_buf_read_map( |
| 639 | struct xfs_buftarg *target, |
| 640 | struct xfs_buf_map *map, |
| 641 | int nmaps, |
| 642 | xfs_buf_flags_t flags, |
| 643 | const struct xfs_buf_ops *ops) |
| 644 | { |
| 645 | struct xfs_buf *bp; |
| 646 | |
| 647 | flags |= XBF_READ; |
| 648 | |
| 649 | bp = xfs_buf_get_map(target, map, nmaps, flags); |
| 650 | if (bp) { |
| 651 | trace_xfs_buf_read(bp, flags, _RET_IP_); |
| 652 | |
| 653 | if (!XFS_BUF_ISDONE(bp)) { |
| 654 | XFS_STATS_INC(target->bt_mount, xb_get_read); |
| 655 | bp->b_ops = ops; |
| 656 | _xfs_buf_read(bp, flags); |
| 657 | } else if (flags & XBF_ASYNC) { |
| 658 | /* |
| 659 | * Read ahead call which is already satisfied, |
| 660 | * drop the buffer |
| 661 | */ |
| 662 | xfs_buf_relse(bp); |
| 663 | return NULL; |
| 664 | } else { |
| 665 | /* We do not want read in the flags */ |
| 666 | bp->b_flags &= ~XBF_READ; |
| 667 | } |
| 668 | } |
| 669 | |
| 670 | return bp; |
| 671 | } |
| 672 | |
| 673 | /* |
| 674 | * If we are not low on memory then do the readahead in a deadlock |
| 675 | * safe manner. |
| 676 | */ |
| 677 | void |
| 678 | xfs_buf_readahead_map( |
| 679 | struct xfs_buftarg *target, |
| 680 | struct xfs_buf_map *map, |
| 681 | int nmaps, |
| 682 | const struct xfs_buf_ops *ops) |
| 683 | { |
| 684 | if (bdi_read_congested(target->bt_bdi)) |
| 685 | return; |
| 686 | |
| 687 | xfs_buf_read_map(target, map, nmaps, |
| 688 | XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD, ops); |
| 689 | } |
| 690 | |
| 691 | /* |
| 692 | * Read an uncached buffer from disk. Allocates and returns a locked |
| 693 | * buffer containing the disk contents or nothing. |
| 694 | */ |
| 695 | int |
| 696 | xfs_buf_read_uncached( |
| 697 | struct xfs_buftarg *target, |
| 698 | xfs_daddr_t daddr, |
| 699 | size_t numblks, |
| 700 | int flags, |
| 701 | struct xfs_buf **bpp, |
| 702 | const struct xfs_buf_ops *ops) |
| 703 | { |
| 704 | struct xfs_buf *bp; |
| 705 | |
| 706 | *bpp = NULL; |
| 707 | |
| 708 | bp = xfs_buf_get_uncached(target, numblks, flags); |
| 709 | if (!bp) |
| 710 | return -ENOMEM; |
| 711 | |
| 712 | /* set up the buffer for a read IO */ |
| 713 | ASSERT(bp->b_map_count == 1); |
| 714 | bp->b_bn = XFS_BUF_DADDR_NULL; /* always null for uncached buffers */ |
| 715 | bp->b_maps[0].bm_bn = daddr; |
| 716 | bp->b_flags |= XBF_READ; |
| 717 | bp->b_ops = ops; |
| 718 | |
| 719 | xfs_buf_submit_wait(bp); |
| 720 | if (bp->b_error) { |
| 721 | int error = bp->b_error; |
| 722 | xfs_buf_relse(bp); |
| 723 | return error; |
| 724 | } |
| 725 | |
| 726 | *bpp = bp; |
| 727 | return 0; |
| 728 | } |
| 729 | |
| 730 | /* |
| 731 | * Return a buffer allocated as an empty buffer and associated to external |
| 732 | * memory via xfs_buf_associate_memory() back to it's empty state. |
| 733 | */ |
| 734 | void |
| 735 | xfs_buf_set_empty( |
| 736 | struct xfs_buf *bp, |
| 737 | size_t numblks) |
| 738 | { |
| 739 | if (bp->b_pages) |
| 740 | _xfs_buf_free_pages(bp); |
| 741 | |
| 742 | bp->b_pages = NULL; |
| 743 | bp->b_page_count = 0; |
| 744 | bp->b_addr = NULL; |
| 745 | bp->b_length = numblks; |
| 746 | bp->b_io_length = numblks; |
| 747 | |
| 748 | ASSERT(bp->b_map_count == 1); |
| 749 | bp->b_bn = XFS_BUF_DADDR_NULL; |
| 750 | bp->b_maps[0].bm_bn = XFS_BUF_DADDR_NULL; |
| 751 | bp->b_maps[0].bm_len = bp->b_length; |
| 752 | } |
| 753 | |
| 754 | static inline struct page * |
| 755 | mem_to_page( |
| 756 | void *addr) |
| 757 | { |
| 758 | if ((!is_vmalloc_addr(addr))) { |
| 759 | return virt_to_page(addr); |
| 760 | } else { |
| 761 | return vmalloc_to_page(addr); |
| 762 | } |
| 763 | } |
| 764 | |
| 765 | int |
| 766 | xfs_buf_associate_memory( |
| 767 | xfs_buf_t *bp, |
| 768 | void *mem, |
| 769 | size_t len) |
| 770 | { |
| 771 | int rval; |
| 772 | int i = 0; |
| 773 | unsigned long pageaddr; |
| 774 | unsigned long offset; |
| 775 | size_t buflen; |
| 776 | int page_count; |
| 777 | |
| 778 | pageaddr = (unsigned long)mem & PAGE_MASK; |
| 779 | offset = (unsigned long)mem - pageaddr; |
| 780 | buflen = PAGE_ALIGN(len + offset); |
| 781 | page_count = buflen >> PAGE_SHIFT; |
| 782 | |
| 783 | /* Free any previous set of page pointers */ |
| 784 | if (bp->b_pages) |
| 785 | _xfs_buf_free_pages(bp); |
| 786 | |
| 787 | bp->b_pages = NULL; |
| 788 | bp->b_addr = mem; |
| 789 | |
| 790 | rval = _xfs_buf_get_pages(bp, page_count); |
| 791 | if (rval) |
| 792 | return rval; |
| 793 | |
| 794 | bp->b_offset = offset; |
| 795 | |
| 796 | for (i = 0; i < bp->b_page_count; i++) { |
| 797 | bp->b_pages[i] = mem_to_page((void *)pageaddr); |
| 798 | pageaddr += PAGE_SIZE; |
| 799 | } |
| 800 | |
| 801 | bp->b_io_length = BTOBB(len); |
| 802 | bp->b_length = BTOBB(buflen); |
| 803 | |
| 804 | return 0; |
| 805 | } |
| 806 | |
| 807 | xfs_buf_t * |
| 808 | xfs_buf_get_uncached( |
| 809 | struct xfs_buftarg *target, |
| 810 | size_t numblks, |
| 811 | int flags) |
| 812 | { |
| 813 | unsigned long page_count; |
| 814 | int error, i; |
| 815 | struct xfs_buf *bp; |
| 816 | DEFINE_SINGLE_BUF_MAP(map, XFS_BUF_DADDR_NULL, numblks); |
| 817 | |
| 818 | bp = _xfs_buf_alloc(target, &map, 1, 0); |
| 819 | if (unlikely(bp == NULL)) |
| 820 | goto fail; |
| 821 | |
| 822 | page_count = PAGE_ALIGN(numblks << BBSHIFT) >> PAGE_SHIFT; |
| 823 | error = _xfs_buf_get_pages(bp, page_count); |
| 824 | if (error) |
| 825 | goto fail_free_buf; |
| 826 | |
| 827 | for (i = 0; i < page_count; i++) { |
| 828 | bp->b_pages[i] = alloc_page(xb_to_gfp(flags)); |
| 829 | if (!bp->b_pages[i]) |
| 830 | goto fail_free_mem; |
| 831 | } |
| 832 | bp->b_flags |= _XBF_PAGES; |
| 833 | |
| 834 | error = _xfs_buf_map_pages(bp, 0); |
| 835 | if (unlikely(error)) { |
| 836 | xfs_warn(target->bt_mount, |
| 837 | "%s: failed to map pages", __func__); |
| 838 | goto fail_free_mem; |
| 839 | } |
| 840 | |
| 841 | trace_xfs_buf_get_uncached(bp, _RET_IP_); |
| 842 | return bp; |
| 843 | |
| 844 | fail_free_mem: |
| 845 | while (--i >= 0) |
| 846 | __free_page(bp->b_pages[i]); |
| 847 | _xfs_buf_free_pages(bp); |
| 848 | fail_free_buf: |
| 849 | xfs_buf_free_maps(bp); |
| 850 | kmem_zone_free(xfs_buf_zone, bp); |
| 851 | fail: |
| 852 | return NULL; |
| 853 | } |
| 854 | |
| 855 | /* |
| 856 | * Increment reference count on buffer, to hold the buffer concurrently |
| 857 | * with another thread which may release (free) the buffer asynchronously. |
| 858 | * Must hold the buffer already to call this function. |
| 859 | */ |
| 860 | void |
| 861 | xfs_buf_hold( |
| 862 | xfs_buf_t *bp) |
| 863 | { |
| 864 | trace_xfs_buf_hold(bp, _RET_IP_); |
| 865 | atomic_inc(&bp->b_hold); |
| 866 | } |
| 867 | |
| 868 | /* |
| 869 | * Releases a hold on the specified buffer. If the |
| 870 | * the hold count is 1, calls xfs_buf_free. |
| 871 | */ |
| 872 | void |
| 873 | xfs_buf_rele( |
| 874 | xfs_buf_t *bp) |
| 875 | { |
| 876 | struct xfs_perag *pag = bp->b_pag; |
| 877 | |
| 878 | trace_xfs_buf_rele(bp, _RET_IP_); |
| 879 | |
| 880 | if (!pag) { |
| 881 | ASSERT(list_empty(&bp->b_lru)); |
| 882 | ASSERT(RB_EMPTY_NODE(&bp->b_rbnode)); |
| 883 | if (atomic_dec_and_test(&bp->b_hold)) |
| 884 | xfs_buf_free(bp); |
| 885 | return; |
| 886 | } |
| 887 | |
| 888 | ASSERT(!RB_EMPTY_NODE(&bp->b_rbnode)); |
| 889 | |
| 890 | ASSERT(atomic_read(&bp->b_hold) > 0); |
| 891 | if (atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock)) { |
| 892 | spin_lock(&bp->b_lock); |
| 893 | if (!(bp->b_flags & XBF_STALE) && atomic_read(&bp->b_lru_ref)) { |
| 894 | /* |
| 895 | * If the buffer is added to the LRU take a new |
| 896 | * reference to the buffer for the LRU and clear the |
| 897 | * (now stale) dispose list state flag |
| 898 | */ |
| 899 | if (list_lru_add(&bp->b_target->bt_lru, &bp->b_lru)) { |
| 900 | bp->b_state &= ~XFS_BSTATE_DISPOSE; |
| 901 | atomic_inc(&bp->b_hold); |
| 902 | } |
| 903 | spin_unlock(&bp->b_lock); |
| 904 | spin_unlock(&pag->pag_buf_lock); |
| 905 | } else { |
| 906 | /* |
| 907 | * most of the time buffers will already be removed from |
| 908 | * the LRU, so optimise that case by checking for the |
| 909 | * XFS_BSTATE_DISPOSE flag indicating the last list the |
| 910 | * buffer was on was the disposal list |
| 911 | */ |
| 912 | if (!(bp->b_state & XFS_BSTATE_DISPOSE)) { |
| 913 | list_lru_del(&bp->b_target->bt_lru, &bp->b_lru); |
| 914 | } else { |
| 915 | ASSERT(list_empty(&bp->b_lru)); |
| 916 | } |
| 917 | spin_unlock(&bp->b_lock); |
| 918 | |
| 919 | ASSERT(!(bp->b_flags & _XBF_DELWRI_Q)); |
| 920 | rb_erase(&bp->b_rbnode, &pag->pag_buf_tree); |
| 921 | spin_unlock(&pag->pag_buf_lock); |
| 922 | xfs_perag_put(pag); |
| 923 | xfs_buf_free(bp); |
| 924 | } |
| 925 | } |
| 926 | } |
| 927 | |
| 928 | |
| 929 | /* |
| 930 | * Lock a buffer object, if it is not already locked. |
| 931 | * |
| 932 | * If we come across a stale, pinned, locked buffer, we know that we are |
| 933 | * being asked to lock a buffer that has been reallocated. Because it is |
| 934 | * pinned, we know that the log has not been pushed to disk and hence it |
| 935 | * will still be locked. Rather than continuing to have trylock attempts |
| 936 | * fail until someone else pushes the log, push it ourselves before |
| 937 | * returning. This means that the xfsaild will not get stuck trying |
| 938 | * to push on stale inode buffers. |
| 939 | */ |
| 940 | int |
| 941 | xfs_buf_trylock( |
| 942 | struct xfs_buf *bp) |
| 943 | { |
| 944 | int locked; |
| 945 | |
| 946 | locked = down_trylock(&bp->b_sema) == 0; |
| 947 | if (locked) |
| 948 | XB_SET_OWNER(bp); |
| 949 | |
| 950 | trace_xfs_buf_trylock(bp, _RET_IP_); |
| 951 | return locked; |
| 952 | } |
| 953 | |
| 954 | /* |
| 955 | * Lock a buffer object. |
| 956 | * |
| 957 | * If we come across a stale, pinned, locked buffer, we know that we |
| 958 | * are being asked to lock a buffer that has been reallocated. Because |
| 959 | * it is pinned, we know that the log has not been pushed to disk and |
| 960 | * hence it will still be locked. Rather than sleeping until someone |
| 961 | * else pushes the log, push it ourselves before trying to get the lock. |
| 962 | */ |
| 963 | void |
| 964 | xfs_buf_lock( |
| 965 | struct xfs_buf *bp) |
| 966 | { |
| 967 | trace_xfs_buf_lock(bp, _RET_IP_); |
| 968 | |
| 969 | if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE)) |
| 970 | xfs_log_force(bp->b_target->bt_mount, 0); |
| 971 | down(&bp->b_sema); |
| 972 | XB_SET_OWNER(bp); |
| 973 | |
| 974 | trace_xfs_buf_lock_done(bp, _RET_IP_); |
| 975 | } |
| 976 | |
| 977 | void |
| 978 | xfs_buf_unlock( |
| 979 | struct xfs_buf *bp) |
| 980 | { |
| 981 | XB_CLEAR_OWNER(bp); |
| 982 | up(&bp->b_sema); |
| 983 | |
| 984 | trace_xfs_buf_unlock(bp, _RET_IP_); |
| 985 | } |
| 986 | |
| 987 | STATIC void |
| 988 | xfs_buf_wait_unpin( |
| 989 | xfs_buf_t *bp) |
| 990 | { |
| 991 | DECLARE_WAITQUEUE (wait, current); |
| 992 | |
| 993 | if (atomic_read(&bp->b_pin_count) == 0) |
| 994 | return; |
| 995 | |
| 996 | add_wait_queue(&bp->b_waiters, &wait); |
| 997 | for (;;) { |
| 998 | set_current_state(TASK_UNINTERRUPTIBLE); |
| 999 | if (atomic_read(&bp->b_pin_count) == 0) |
| 1000 | break; |
| 1001 | io_schedule(); |
| 1002 | } |
| 1003 | remove_wait_queue(&bp->b_waiters, &wait); |
| 1004 | set_current_state(TASK_RUNNING); |
| 1005 | } |
| 1006 | |
| 1007 | /* |
| 1008 | * Buffer Utility Routines |
| 1009 | */ |
| 1010 | |
| 1011 | void |
| 1012 | xfs_buf_ioend( |
| 1013 | struct xfs_buf *bp) |
| 1014 | { |
| 1015 | bool read = bp->b_flags & XBF_READ; |
| 1016 | |
| 1017 | trace_xfs_buf_iodone(bp, _RET_IP_); |
| 1018 | |
| 1019 | bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD); |
| 1020 | |
| 1021 | /* |
| 1022 | * Pull in IO completion errors now. We are guaranteed to be running |
| 1023 | * single threaded, so we don't need the lock to read b_io_error. |
| 1024 | */ |
| 1025 | if (!bp->b_error && bp->b_io_error) |
| 1026 | xfs_buf_ioerror(bp, bp->b_io_error); |
| 1027 | |
| 1028 | /* Only validate buffers that were read without errors */ |
| 1029 | if (read && !bp->b_error && bp->b_ops) { |
| 1030 | ASSERT(!bp->b_iodone); |
| 1031 | bp->b_ops->verify_read(bp); |
| 1032 | } |
| 1033 | |
| 1034 | if (!bp->b_error) |
| 1035 | bp->b_flags |= XBF_DONE; |
| 1036 | |
| 1037 | if (bp->b_iodone) |
| 1038 | (*(bp->b_iodone))(bp); |
| 1039 | else if (bp->b_flags & XBF_ASYNC) |
| 1040 | xfs_buf_relse(bp); |
| 1041 | else |
| 1042 | complete(&bp->b_iowait); |
| 1043 | } |
| 1044 | |
| 1045 | static void |
| 1046 | xfs_buf_ioend_work( |
| 1047 | struct work_struct *work) |
| 1048 | { |
| 1049 | struct xfs_buf *bp = |
| 1050 | container_of(work, xfs_buf_t, b_ioend_work); |
| 1051 | |
| 1052 | xfs_buf_ioend(bp); |
| 1053 | } |
| 1054 | |
| 1055 | static void |
| 1056 | xfs_buf_ioend_async( |
| 1057 | struct xfs_buf *bp) |
| 1058 | { |
| 1059 | INIT_WORK(&bp->b_ioend_work, xfs_buf_ioend_work); |
| 1060 | queue_work(bp->b_ioend_wq, &bp->b_ioend_work); |
| 1061 | } |
| 1062 | |
| 1063 | void |
| 1064 | xfs_buf_ioerror( |
| 1065 | xfs_buf_t *bp, |
| 1066 | int error) |
| 1067 | { |
| 1068 | ASSERT(error <= 0 && error >= -1000); |
| 1069 | bp->b_error = error; |
| 1070 | trace_xfs_buf_ioerror(bp, error, _RET_IP_); |
| 1071 | } |
| 1072 | |
| 1073 | void |
| 1074 | xfs_buf_ioerror_alert( |
| 1075 | struct xfs_buf *bp, |
| 1076 | const char *func) |
| 1077 | { |
| 1078 | xfs_alert(bp->b_target->bt_mount, |
| 1079 | "metadata I/O error: block 0x%llx (\"%s\") error %d numblks %d", |
| 1080 | (__uint64_t)XFS_BUF_ADDR(bp), func, -bp->b_error, bp->b_length); |
| 1081 | } |
| 1082 | |
| 1083 | int |
| 1084 | xfs_bwrite( |
| 1085 | struct xfs_buf *bp) |
| 1086 | { |
| 1087 | int error; |
| 1088 | |
| 1089 | ASSERT(xfs_buf_islocked(bp)); |
| 1090 | |
| 1091 | bp->b_flags |= XBF_WRITE; |
| 1092 | bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q | |
| 1093 | XBF_WRITE_FAIL | XBF_DONE); |
| 1094 | |
| 1095 | error = xfs_buf_submit_wait(bp); |
| 1096 | if (error) { |
| 1097 | xfs_force_shutdown(bp->b_target->bt_mount, |
| 1098 | SHUTDOWN_META_IO_ERROR); |
| 1099 | } |
| 1100 | return error; |
| 1101 | } |
| 1102 | |
| 1103 | STATIC void |
| 1104 | xfs_buf_bio_end_io( |
| 1105 | struct bio *bio) |
| 1106 | { |
| 1107 | xfs_buf_t *bp = (xfs_buf_t *)bio->bi_private; |
| 1108 | |
| 1109 | /* |
| 1110 | * don't overwrite existing errors - otherwise we can lose errors on |
| 1111 | * buffers that require multiple bios to complete. |
| 1112 | */ |
| 1113 | if (bio->bi_error) { |
| 1114 | spin_lock(&bp->b_lock); |
| 1115 | if (!bp->b_io_error) |
| 1116 | bp->b_io_error = bio->bi_error; |
| 1117 | spin_unlock(&bp->b_lock); |
| 1118 | } |
| 1119 | |
| 1120 | if (!bp->b_error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ)) |
| 1121 | invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp)); |
| 1122 | |
| 1123 | if (atomic_dec_and_test(&bp->b_io_remaining) == 1) |
| 1124 | xfs_buf_ioend_async(bp); |
| 1125 | bio_put(bio); |
| 1126 | } |
| 1127 | |
| 1128 | static void |
| 1129 | xfs_buf_ioapply_map( |
| 1130 | struct xfs_buf *bp, |
| 1131 | int map, |
| 1132 | int *buf_offset, |
| 1133 | int *count, |
| 1134 | int rw) |
| 1135 | { |
| 1136 | int page_index; |
| 1137 | int total_nr_pages = bp->b_page_count; |
| 1138 | int nr_pages; |
| 1139 | struct bio *bio; |
| 1140 | sector_t sector = bp->b_maps[map].bm_bn; |
| 1141 | int size; |
| 1142 | int offset; |
| 1143 | |
| 1144 | total_nr_pages = bp->b_page_count; |
| 1145 | |
| 1146 | /* skip the pages in the buffer before the start offset */ |
| 1147 | page_index = 0; |
| 1148 | offset = *buf_offset; |
| 1149 | while (offset >= PAGE_SIZE) { |
| 1150 | page_index++; |
| 1151 | offset -= PAGE_SIZE; |
| 1152 | } |
| 1153 | |
| 1154 | /* |
| 1155 | * Limit the IO size to the length of the current vector, and update the |
| 1156 | * remaining IO count for the next time around. |
| 1157 | */ |
| 1158 | size = min_t(int, BBTOB(bp->b_maps[map].bm_len), *count); |
| 1159 | *count -= size; |
| 1160 | *buf_offset += size; |
| 1161 | |
| 1162 | next_chunk: |
| 1163 | atomic_inc(&bp->b_io_remaining); |
| 1164 | nr_pages = BIO_MAX_SECTORS >> (PAGE_SHIFT - BBSHIFT); |
| 1165 | if (nr_pages > total_nr_pages) |
| 1166 | nr_pages = total_nr_pages; |
| 1167 | |
| 1168 | bio = bio_alloc(GFP_NOIO, nr_pages); |
| 1169 | bio->bi_bdev = bp->b_target->bt_bdev; |
| 1170 | bio->bi_iter.bi_sector = sector; |
| 1171 | bio->bi_end_io = xfs_buf_bio_end_io; |
| 1172 | bio->bi_private = bp; |
| 1173 | |
| 1174 | |
| 1175 | for (; size && nr_pages; nr_pages--, page_index++) { |
| 1176 | int rbytes, nbytes = PAGE_SIZE - offset; |
| 1177 | |
| 1178 | if (nbytes > size) |
| 1179 | nbytes = size; |
| 1180 | |
| 1181 | rbytes = bio_add_page(bio, bp->b_pages[page_index], nbytes, |
| 1182 | offset); |
| 1183 | if (rbytes < nbytes) |
| 1184 | break; |
| 1185 | |
| 1186 | offset = 0; |
| 1187 | sector += BTOBB(nbytes); |
| 1188 | size -= nbytes; |
| 1189 | total_nr_pages--; |
| 1190 | } |
| 1191 | |
| 1192 | if (likely(bio->bi_iter.bi_size)) { |
| 1193 | if (xfs_buf_is_vmapped(bp)) { |
| 1194 | flush_kernel_vmap_range(bp->b_addr, |
| 1195 | xfs_buf_vmap_len(bp)); |
| 1196 | } |
| 1197 | submit_bio(rw, bio); |
| 1198 | if (size) |
| 1199 | goto next_chunk; |
| 1200 | } else { |
| 1201 | /* |
| 1202 | * This is guaranteed not to be the last io reference count |
| 1203 | * because the caller (xfs_buf_submit) holds a count itself. |
| 1204 | */ |
| 1205 | atomic_dec(&bp->b_io_remaining); |
| 1206 | xfs_buf_ioerror(bp, -EIO); |
| 1207 | bio_put(bio); |
| 1208 | } |
| 1209 | |
| 1210 | } |
| 1211 | |
| 1212 | STATIC void |
| 1213 | _xfs_buf_ioapply( |
| 1214 | struct xfs_buf *bp) |
| 1215 | { |
| 1216 | struct blk_plug plug; |
| 1217 | int rw; |
| 1218 | int offset; |
| 1219 | int size; |
| 1220 | int i; |
| 1221 | |
| 1222 | /* |
| 1223 | * Make sure we capture only current IO errors rather than stale errors |
| 1224 | * left over from previous use of the buffer (e.g. failed readahead). |
| 1225 | */ |
| 1226 | bp->b_error = 0; |
| 1227 | |
| 1228 | /* |
| 1229 | * Initialize the I/O completion workqueue if we haven't yet or the |
| 1230 | * submitter has not opted to specify a custom one. |
| 1231 | */ |
| 1232 | if (!bp->b_ioend_wq) |
| 1233 | bp->b_ioend_wq = bp->b_target->bt_mount->m_buf_workqueue; |
| 1234 | |
| 1235 | if (bp->b_flags & XBF_WRITE) { |
| 1236 | if (bp->b_flags & XBF_SYNCIO) |
| 1237 | rw = WRITE_SYNC; |
| 1238 | else |
| 1239 | rw = WRITE; |
| 1240 | if (bp->b_flags & XBF_FUA) |
| 1241 | rw |= REQ_FUA; |
| 1242 | if (bp->b_flags & XBF_FLUSH) |
| 1243 | rw |= REQ_FLUSH; |
| 1244 | |
| 1245 | /* |
| 1246 | * Run the write verifier callback function if it exists. If |
| 1247 | * this function fails it will mark the buffer with an error and |
| 1248 | * the IO should not be dispatched. |
| 1249 | */ |
| 1250 | if (bp->b_ops) { |
| 1251 | bp->b_ops->verify_write(bp); |
| 1252 | if (bp->b_error) { |
| 1253 | xfs_force_shutdown(bp->b_target->bt_mount, |
| 1254 | SHUTDOWN_CORRUPT_INCORE); |
| 1255 | return; |
| 1256 | } |
| 1257 | } else if (bp->b_bn != XFS_BUF_DADDR_NULL) { |
| 1258 | struct xfs_mount *mp = bp->b_target->bt_mount; |
| 1259 | |
| 1260 | /* |
| 1261 | * non-crc filesystems don't attach verifiers during |
| 1262 | * log recovery, so don't warn for such filesystems. |
| 1263 | */ |
| 1264 | if (xfs_sb_version_hascrc(&mp->m_sb)) { |
| 1265 | xfs_warn(mp, |
| 1266 | "%s: no ops on block 0x%llx/0x%x", |
| 1267 | __func__, bp->b_bn, bp->b_length); |
| 1268 | xfs_hex_dump(bp->b_addr, 64); |
| 1269 | dump_stack(); |
| 1270 | } |
| 1271 | } |
| 1272 | } else if (bp->b_flags & XBF_READ_AHEAD) { |
| 1273 | rw = READA; |
| 1274 | } else { |
| 1275 | rw = READ; |
| 1276 | } |
| 1277 | |
| 1278 | /* we only use the buffer cache for meta-data */ |
| 1279 | rw |= REQ_META; |
| 1280 | |
| 1281 | /* |
| 1282 | * Walk all the vectors issuing IO on them. Set up the initial offset |
| 1283 | * into the buffer and the desired IO size before we start - |
| 1284 | * _xfs_buf_ioapply_vec() will modify them appropriately for each |
| 1285 | * subsequent call. |
| 1286 | */ |
| 1287 | offset = bp->b_offset; |
| 1288 | size = BBTOB(bp->b_io_length); |
| 1289 | blk_start_plug(&plug); |
| 1290 | for (i = 0; i < bp->b_map_count; i++) { |
| 1291 | xfs_buf_ioapply_map(bp, i, &offset, &size, rw); |
| 1292 | if (bp->b_error) |
| 1293 | break; |
| 1294 | if (size <= 0) |
| 1295 | break; /* all done */ |
| 1296 | } |
| 1297 | blk_finish_plug(&plug); |
| 1298 | } |
| 1299 | |
| 1300 | /* |
| 1301 | * Asynchronous IO submission path. This transfers the buffer lock ownership and |
| 1302 | * the current reference to the IO. It is not safe to reference the buffer after |
| 1303 | * a call to this function unless the caller holds an additional reference |
| 1304 | * itself. |
| 1305 | */ |
| 1306 | void |
| 1307 | xfs_buf_submit( |
| 1308 | struct xfs_buf *bp) |
| 1309 | { |
| 1310 | trace_xfs_buf_submit(bp, _RET_IP_); |
| 1311 | |
| 1312 | ASSERT(!(bp->b_flags & _XBF_DELWRI_Q)); |
| 1313 | ASSERT(bp->b_flags & XBF_ASYNC); |
| 1314 | |
| 1315 | /* on shutdown we stale and complete the buffer immediately */ |
| 1316 | if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) { |
| 1317 | xfs_buf_ioerror(bp, -EIO); |
| 1318 | bp->b_flags &= ~XBF_DONE; |
| 1319 | xfs_buf_stale(bp); |
| 1320 | xfs_buf_ioend(bp); |
| 1321 | return; |
| 1322 | } |
| 1323 | |
| 1324 | if (bp->b_flags & XBF_WRITE) |
| 1325 | xfs_buf_wait_unpin(bp); |
| 1326 | |
| 1327 | /* clear the internal error state to avoid spurious errors */ |
| 1328 | bp->b_io_error = 0; |
| 1329 | |
| 1330 | /* |
| 1331 | * The caller's reference is released during I/O completion. |
| 1332 | * This occurs some time after the last b_io_remaining reference is |
| 1333 | * released, so after we drop our Io reference we have to have some |
| 1334 | * other reference to ensure the buffer doesn't go away from underneath |
| 1335 | * us. Take a direct reference to ensure we have safe access to the |
| 1336 | * buffer until we are finished with it. |
| 1337 | */ |
| 1338 | xfs_buf_hold(bp); |
| 1339 | |
| 1340 | /* |
| 1341 | * Set the count to 1 initially, this will stop an I/O completion |
| 1342 | * callout which happens before we have started all the I/O from calling |
| 1343 | * xfs_buf_ioend too early. |
| 1344 | */ |
| 1345 | atomic_set(&bp->b_io_remaining, 1); |
| 1346 | _xfs_buf_ioapply(bp); |
| 1347 | |
| 1348 | /* |
| 1349 | * If _xfs_buf_ioapply failed, we can get back here with only the IO |
| 1350 | * reference we took above. If we drop it to zero, run completion so |
| 1351 | * that we don't return to the caller with completion still pending. |
| 1352 | */ |
| 1353 | if (atomic_dec_and_test(&bp->b_io_remaining) == 1) { |
| 1354 | if (bp->b_error) |
| 1355 | xfs_buf_ioend(bp); |
| 1356 | else |
| 1357 | xfs_buf_ioend_async(bp); |
| 1358 | } |
| 1359 | |
| 1360 | xfs_buf_rele(bp); |
| 1361 | /* Note: it is not safe to reference bp now we've dropped our ref */ |
| 1362 | } |
| 1363 | |
| 1364 | /* |
| 1365 | * Synchronous buffer IO submission path, read or write. |
| 1366 | */ |
| 1367 | int |
| 1368 | xfs_buf_submit_wait( |
| 1369 | struct xfs_buf *bp) |
| 1370 | { |
| 1371 | int error; |
| 1372 | |
| 1373 | trace_xfs_buf_submit_wait(bp, _RET_IP_); |
| 1374 | |
| 1375 | ASSERT(!(bp->b_flags & (_XBF_DELWRI_Q | XBF_ASYNC))); |
| 1376 | |
| 1377 | if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) { |
| 1378 | xfs_buf_ioerror(bp, -EIO); |
| 1379 | xfs_buf_stale(bp); |
| 1380 | bp->b_flags &= ~XBF_DONE; |
| 1381 | return -EIO; |
| 1382 | } |
| 1383 | |
| 1384 | if (bp->b_flags & XBF_WRITE) |
| 1385 | xfs_buf_wait_unpin(bp); |
| 1386 | |
| 1387 | /* clear the internal error state to avoid spurious errors */ |
| 1388 | bp->b_io_error = 0; |
| 1389 | |
| 1390 | /* |
| 1391 | * For synchronous IO, the IO does not inherit the submitters reference |
| 1392 | * count, nor the buffer lock. Hence we cannot release the reference we |
| 1393 | * are about to take until we've waited for all IO completion to occur, |
| 1394 | * including any xfs_buf_ioend_async() work that may be pending. |
| 1395 | */ |
| 1396 | xfs_buf_hold(bp); |
| 1397 | |
| 1398 | /* |
| 1399 | * Set the count to 1 initially, this will stop an I/O completion |
| 1400 | * callout which happens before we have started all the I/O from calling |
| 1401 | * xfs_buf_ioend too early. |
| 1402 | */ |
| 1403 | atomic_set(&bp->b_io_remaining, 1); |
| 1404 | _xfs_buf_ioapply(bp); |
| 1405 | |
| 1406 | /* |
| 1407 | * make sure we run completion synchronously if it raced with us and is |
| 1408 | * already complete. |
| 1409 | */ |
| 1410 | if (atomic_dec_and_test(&bp->b_io_remaining) == 1) |
| 1411 | xfs_buf_ioend(bp); |
| 1412 | |
| 1413 | /* wait for completion before gathering the error from the buffer */ |
| 1414 | trace_xfs_buf_iowait(bp, _RET_IP_); |
| 1415 | wait_for_completion(&bp->b_iowait); |
| 1416 | trace_xfs_buf_iowait_done(bp, _RET_IP_); |
| 1417 | error = bp->b_error; |
| 1418 | |
| 1419 | /* |
| 1420 | * all done now, we can release the hold that keeps the buffer |
| 1421 | * referenced for the entire IO. |
| 1422 | */ |
| 1423 | xfs_buf_rele(bp); |
| 1424 | return error; |
| 1425 | } |
| 1426 | |
| 1427 | void * |
| 1428 | xfs_buf_offset( |
| 1429 | struct xfs_buf *bp, |
| 1430 | size_t offset) |
| 1431 | { |
| 1432 | struct page *page; |
| 1433 | |
| 1434 | if (bp->b_addr) |
| 1435 | return bp->b_addr + offset; |
| 1436 | |
| 1437 | offset += bp->b_offset; |
| 1438 | page = bp->b_pages[offset >> PAGE_SHIFT]; |
| 1439 | return page_address(page) + (offset & (PAGE_SIZE-1)); |
| 1440 | } |
| 1441 | |
| 1442 | /* |
| 1443 | * Move data into or out of a buffer. |
| 1444 | */ |
| 1445 | void |
| 1446 | xfs_buf_iomove( |
| 1447 | xfs_buf_t *bp, /* buffer to process */ |
| 1448 | size_t boff, /* starting buffer offset */ |
| 1449 | size_t bsize, /* length to copy */ |
| 1450 | void *data, /* data address */ |
| 1451 | xfs_buf_rw_t mode) /* read/write/zero flag */ |
| 1452 | { |
| 1453 | size_t bend; |
| 1454 | |
| 1455 | bend = boff + bsize; |
| 1456 | while (boff < bend) { |
| 1457 | struct page *page; |
| 1458 | int page_index, page_offset, csize; |
| 1459 | |
| 1460 | page_index = (boff + bp->b_offset) >> PAGE_SHIFT; |
| 1461 | page_offset = (boff + bp->b_offset) & ~PAGE_MASK; |
| 1462 | page = bp->b_pages[page_index]; |
| 1463 | csize = min_t(size_t, PAGE_SIZE - page_offset, |
| 1464 | BBTOB(bp->b_io_length) - boff); |
| 1465 | |
| 1466 | ASSERT((csize + page_offset) <= PAGE_SIZE); |
| 1467 | |
| 1468 | switch (mode) { |
| 1469 | case XBRW_ZERO: |
| 1470 | memset(page_address(page) + page_offset, 0, csize); |
| 1471 | break; |
| 1472 | case XBRW_READ: |
| 1473 | memcpy(data, page_address(page) + page_offset, csize); |
| 1474 | break; |
| 1475 | case XBRW_WRITE: |
| 1476 | memcpy(page_address(page) + page_offset, data, csize); |
| 1477 | } |
| 1478 | |
| 1479 | boff += csize; |
| 1480 | data += csize; |
| 1481 | } |
| 1482 | } |
| 1483 | |
| 1484 | /* |
| 1485 | * Handling of buffer targets (buftargs). |
| 1486 | */ |
| 1487 | |
| 1488 | /* |
| 1489 | * Wait for any bufs with callbacks that have been submitted but have not yet |
| 1490 | * returned. These buffers will have an elevated hold count, so wait on those |
| 1491 | * while freeing all the buffers only held by the LRU. |
| 1492 | */ |
| 1493 | static enum lru_status |
| 1494 | xfs_buftarg_wait_rele( |
| 1495 | struct list_head *item, |
| 1496 | struct list_lru_one *lru, |
| 1497 | spinlock_t *lru_lock, |
| 1498 | void *arg) |
| 1499 | |
| 1500 | { |
| 1501 | struct xfs_buf *bp = container_of(item, struct xfs_buf, b_lru); |
| 1502 | struct list_head *dispose = arg; |
| 1503 | |
| 1504 | if (atomic_read(&bp->b_hold) > 1) { |
| 1505 | /* need to wait, so skip it this pass */ |
| 1506 | trace_xfs_buf_wait_buftarg(bp, _RET_IP_); |
| 1507 | return LRU_SKIP; |
| 1508 | } |
| 1509 | if (!spin_trylock(&bp->b_lock)) |
| 1510 | return LRU_SKIP; |
| 1511 | |
| 1512 | /* |
| 1513 | * clear the LRU reference count so the buffer doesn't get |
| 1514 | * ignored in xfs_buf_rele(). |
| 1515 | */ |
| 1516 | atomic_set(&bp->b_lru_ref, 0); |
| 1517 | bp->b_state |= XFS_BSTATE_DISPOSE; |
| 1518 | list_lru_isolate_move(lru, item, dispose); |
| 1519 | spin_unlock(&bp->b_lock); |
| 1520 | return LRU_REMOVED; |
| 1521 | } |
| 1522 | |
| 1523 | void |
| 1524 | xfs_wait_buftarg( |
| 1525 | struct xfs_buftarg *btp) |
| 1526 | { |
| 1527 | LIST_HEAD(dispose); |
| 1528 | int loop = 0; |
| 1529 | |
| 1530 | /* |
| 1531 | * We need to flush the buffer workqueue to ensure that all IO |
| 1532 | * completion processing is 100% done. Just waiting on buffer locks is |
| 1533 | * not sufficient for async IO as the reference count held over IO is |
| 1534 | * not released until after the buffer lock is dropped. Hence we need to |
| 1535 | * ensure here that all reference counts have been dropped before we |
| 1536 | * start walking the LRU list. |
| 1537 | */ |
| 1538 | drain_workqueue(btp->bt_mount->m_buf_workqueue); |
| 1539 | |
| 1540 | /* loop until there is nothing left on the lru list. */ |
| 1541 | while (list_lru_count(&btp->bt_lru)) { |
| 1542 | list_lru_walk(&btp->bt_lru, xfs_buftarg_wait_rele, |
| 1543 | &dispose, LONG_MAX); |
| 1544 | |
| 1545 | while (!list_empty(&dispose)) { |
| 1546 | struct xfs_buf *bp; |
| 1547 | bp = list_first_entry(&dispose, struct xfs_buf, b_lru); |
| 1548 | list_del_init(&bp->b_lru); |
| 1549 | if (bp->b_flags & XBF_WRITE_FAIL) { |
| 1550 | xfs_alert(btp->bt_mount, |
| 1551 | "Corruption Alert: Buffer at block 0x%llx had permanent write failures!", |
| 1552 | (long long)bp->b_bn); |
| 1553 | xfs_alert(btp->bt_mount, |
| 1554 | "Please run xfs_repair to determine the extent of the problem."); |
| 1555 | } |
| 1556 | xfs_buf_rele(bp); |
| 1557 | } |
| 1558 | if (loop++ != 0) |
| 1559 | delay(100); |
| 1560 | } |
| 1561 | } |
| 1562 | |
| 1563 | static enum lru_status |
| 1564 | xfs_buftarg_isolate( |
| 1565 | struct list_head *item, |
| 1566 | struct list_lru_one *lru, |
| 1567 | spinlock_t *lru_lock, |
| 1568 | void *arg) |
| 1569 | { |
| 1570 | struct xfs_buf *bp = container_of(item, struct xfs_buf, b_lru); |
| 1571 | struct list_head *dispose = arg; |
| 1572 | |
| 1573 | /* |
| 1574 | * we are inverting the lru lock/bp->b_lock here, so use a trylock. |
| 1575 | * If we fail to get the lock, just skip it. |
| 1576 | */ |
| 1577 | if (!spin_trylock(&bp->b_lock)) |
| 1578 | return LRU_SKIP; |
| 1579 | /* |
| 1580 | * Decrement the b_lru_ref count unless the value is already |
| 1581 | * zero. If the value is already zero, we need to reclaim the |
| 1582 | * buffer, otherwise it gets another trip through the LRU. |
| 1583 | */ |
| 1584 | if (!atomic_add_unless(&bp->b_lru_ref, -1, 0)) { |
| 1585 | spin_unlock(&bp->b_lock); |
| 1586 | return LRU_ROTATE; |
| 1587 | } |
| 1588 | |
| 1589 | bp->b_state |= XFS_BSTATE_DISPOSE; |
| 1590 | list_lru_isolate_move(lru, item, dispose); |
| 1591 | spin_unlock(&bp->b_lock); |
| 1592 | return LRU_REMOVED; |
| 1593 | } |
| 1594 | |
| 1595 | static unsigned long |
| 1596 | xfs_buftarg_shrink_scan( |
| 1597 | struct shrinker *shrink, |
| 1598 | struct shrink_control *sc) |
| 1599 | { |
| 1600 | struct xfs_buftarg *btp = container_of(shrink, |
| 1601 | struct xfs_buftarg, bt_shrinker); |
| 1602 | LIST_HEAD(dispose); |
| 1603 | unsigned long freed; |
| 1604 | |
| 1605 | freed = list_lru_shrink_walk(&btp->bt_lru, sc, |
| 1606 | xfs_buftarg_isolate, &dispose); |
| 1607 | |
| 1608 | while (!list_empty(&dispose)) { |
| 1609 | struct xfs_buf *bp; |
| 1610 | bp = list_first_entry(&dispose, struct xfs_buf, b_lru); |
| 1611 | list_del_init(&bp->b_lru); |
| 1612 | xfs_buf_rele(bp); |
| 1613 | } |
| 1614 | |
| 1615 | return freed; |
| 1616 | } |
| 1617 | |
| 1618 | static unsigned long |
| 1619 | xfs_buftarg_shrink_count( |
| 1620 | struct shrinker *shrink, |
| 1621 | struct shrink_control *sc) |
| 1622 | { |
| 1623 | struct xfs_buftarg *btp = container_of(shrink, |
| 1624 | struct xfs_buftarg, bt_shrinker); |
| 1625 | return list_lru_shrink_count(&btp->bt_lru, sc); |
| 1626 | } |
| 1627 | |
| 1628 | void |
| 1629 | xfs_free_buftarg( |
| 1630 | struct xfs_mount *mp, |
| 1631 | struct xfs_buftarg *btp) |
| 1632 | { |
| 1633 | unregister_shrinker(&btp->bt_shrinker); |
| 1634 | list_lru_destroy(&btp->bt_lru); |
| 1635 | |
| 1636 | if (mp->m_flags & XFS_MOUNT_BARRIER) |
| 1637 | xfs_blkdev_issue_flush(btp); |
| 1638 | |
| 1639 | kmem_free(btp); |
| 1640 | } |
| 1641 | |
| 1642 | int |
| 1643 | xfs_setsize_buftarg( |
| 1644 | xfs_buftarg_t *btp, |
| 1645 | unsigned int sectorsize) |
| 1646 | { |
| 1647 | /* Set up metadata sector size info */ |
| 1648 | btp->bt_meta_sectorsize = sectorsize; |
| 1649 | btp->bt_meta_sectormask = sectorsize - 1; |
| 1650 | |
| 1651 | if (set_blocksize(btp->bt_bdev, sectorsize)) { |
| 1652 | xfs_warn(btp->bt_mount, |
| 1653 | "Cannot set_blocksize to %u on device %pg", |
| 1654 | sectorsize, btp->bt_bdev); |
| 1655 | return -EINVAL; |
| 1656 | } |
| 1657 | |
| 1658 | /* Set up device logical sector size mask */ |
| 1659 | btp->bt_logical_sectorsize = bdev_logical_block_size(btp->bt_bdev); |
| 1660 | btp->bt_logical_sectormask = bdev_logical_block_size(btp->bt_bdev) - 1; |
| 1661 | |
| 1662 | return 0; |
| 1663 | } |
| 1664 | |
| 1665 | /* |
| 1666 | * When allocating the initial buffer target we have not yet |
| 1667 | * read in the superblock, so don't know what sized sectors |
| 1668 | * are being used at this early stage. Play safe. |
| 1669 | */ |
| 1670 | STATIC int |
| 1671 | xfs_setsize_buftarg_early( |
| 1672 | xfs_buftarg_t *btp, |
| 1673 | struct block_device *bdev) |
| 1674 | { |
| 1675 | return xfs_setsize_buftarg(btp, bdev_logical_block_size(bdev)); |
| 1676 | } |
| 1677 | |
| 1678 | xfs_buftarg_t * |
| 1679 | xfs_alloc_buftarg( |
| 1680 | struct xfs_mount *mp, |
| 1681 | struct block_device *bdev) |
| 1682 | { |
| 1683 | xfs_buftarg_t *btp; |
| 1684 | |
| 1685 | btp = kmem_zalloc(sizeof(*btp), KM_SLEEP | KM_NOFS); |
| 1686 | |
| 1687 | btp->bt_mount = mp; |
| 1688 | btp->bt_dev = bdev->bd_dev; |
| 1689 | btp->bt_bdev = bdev; |
| 1690 | btp->bt_bdi = blk_get_backing_dev_info(bdev); |
| 1691 | |
| 1692 | if (xfs_setsize_buftarg_early(btp, bdev)) |
| 1693 | goto error; |
| 1694 | |
| 1695 | if (list_lru_init(&btp->bt_lru)) |
| 1696 | goto error; |
| 1697 | |
| 1698 | btp->bt_shrinker.count_objects = xfs_buftarg_shrink_count; |
| 1699 | btp->bt_shrinker.scan_objects = xfs_buftarg_shrink_scan; |
| 1700 | btp->bt_shrinker.seeks = DEFAULT_SEEKS; |
| 1701 | btp->bt_shrinker.flags = SHRINKER_NUMA_AWARE; |
| 1702 | register_shrinker(&btp->bt_shrinker); |
| 1703 | return btp; |
| 1704 | |
| 1705 | error: |
| 1706 | kmem_free(btp); |
| 1707 | return NULL; |
| 1708 | } |
| 1709 | |
| 1710 | /* |
| 1711 | * Add a buffer to the delayed write list. |
| 1712 | * |
| 1713 | * This queues a buffer for writeout if it hasn't already been. Note that |
| 1714 | * neither this routine nor the buffer list submission functions perform |
| 1715 | * any internal synchronization. It is expected that the lists are thread-local |
| 1716 | * to the callers. |
| 1717 | * |
| 1718 | * Returns true if we queued up the buffer, or false if it already had |
| 1719 | * been on the buffer list. |
| 1720 | */ |
| 1721 | bool |
| 1722 | xfs_buf_delwri_queue( |
| 1723 | struct xfs_buf *bp, |
| 1724 | struct list_head *list) |
| 1725 | { |
| 1726 | ASSERT(xfs_buf_islocked(bp)); |
| 1727 | ASSERT(!(bp->b_flags & XBF_READ)); |
| 1728 | |
| 1729 | /* |
| 1730 | * If the buffer is already marked delwri it already is queued up |
| 1731 | * by someone else for imediate writeout. Just ignore it in that |
| 1732 | * case. |
| 1733 | */ |
| 1734 | if (bp->b_flags & _XBF_DELWRI_Q) { |
| 1735 | trace_xfs_buf_delwri_queued(bp, _RET_IP_); |
| 1736 | return false; |
| 1737 | } |
| 1738 | |
| 1739 | trace_xfs_buf_delwri_queue(bp, _RET_IP_); |
| 1740 | |
| 1741 | /* |
| 1742 | * If a buffer gets written out synchronously or marked stale while it |
| 1743 | * is on a delwri list we lazily remove it. To do this, the other party |
| 1744 | * clears the _XBF_DELWRI_Q flag but otherwise leaves the buffer alone. |
| 1745 | * It remains referenced and on the list. In a rare corner case it |
| 1746 | * might get readded to a delwri list after the synchronous writeout, in |
| 1747 | * which case we need just need to re-add the flag here. |
| 1748 | */ |
| 1749 | bp->b_flags |= _XBF_DELWRI_Q; |
| 1750 | if (list_empty(&bp->b_list)) { |
| 1751 | atomic_inc(&bp->b_hold); |
| 1752 | list_add_tail(&bp->b_list, list); |
| 1753 | } |
| 1754 | |
| 1755 | return true; |
| 1756 | } |
| 1757 | |
| 1758 | /* |
| 1759 | * Compare function is more complex than it needs to be because |
| 1760 | * the return value is only 32 bits and we are doing comparisons |
| 1761 | * on 64 bit values |
| 1762 | */ |
| 1763 | static int |
| 1764 | xfs_buf_cmp( |
| 1765 | void *priv, |
| 1766 | struct list_head *a, |
| 1767 | struct list_head *b) |
| 1768 | { |
| 1769 | struct xfs_buf *ap = container_of(a, struct xfs_buf, b_list); |
| 1770 | struct xfs_buf *bp = container_of(b, struct xfs_buf, b_list); |
| 1771 | xfs_daddr_t diff; |
| 1772 | |
| 1773 | diff = ap->b_maps[0].bm_bn - bp->b_maps[0].bm_bn; |
| 1774 | if (diff < 0) |
| 1775 | return -1; |
| 1776 | if (diff > 0) |
| 1777 | return 1; |
| 1778 | return 0; |
| 1779 | } |
| 1780 | |
| 1781 | static int |
| 1782 | __xfs_buf_delwri_submit( |
| 1783 | struct list_head *buffer_list, |
| 1784 | struct list_head *io_list, |
| 1785 | bool wait) |
| 1786 | { |
| 1787 | struct blk_plug plug; |
| 1788 | struct xfs_buf *bp, *n; |
| 1789 | int pinned = 0; |
| 1790 | |
| 1791 | list_for_each_entry_safe(bp, n, buffer_list, b_list) { |
| 1792 | if (!wait) { |
| 1793 | if (xfs_buf_ispinned(bp)) { |
| 1794 | pinned++; |
| 1795 | continue; |
| 1796 | } |
| 1797 | if (!xfs_buf_trylock(bp)) |
| 1798 | continue; |
| 1799 | } else { |
| 1800 | xfs_buf_lock(bp); |
| 1801 | } |
| 1802 | |
| 1803 | /* |
| 1804 | * Someone else might have written the buffer synchronously or |
| 1805 | * marked it stale in the meantime. In that case only the |
| 1806 | * _XBF_DELWRI_Q flag got cleared, and we have to drop the |
| 1807 | * reference and remove it from the list here. |
| 1808 | */ |
| 1809 | if (!(bp->b_flags & _XBF_DELWRI_Q)) { |
| 1810 | list_del_init(&bp->b_list); |
| 1811 | xfs_buf_relse(bp); |
| 1812 | continue; |
| 1813 | } |
| 1814 | |
| 1815 | list_move_tail(&bp->b_list, io_list); |
| 1816 | trace_xfs_buf_delwri_split(bp, _RET_IP_); |
| 1817 | } |
| 1818 | |
| 1819 | list_sort(NULL, io_list, xfs_buf_cmp); |
| 1820 | |
| 1821 | blk_start_plug(&plug); |
| 1822 | list_for_each_entry_safe(bp, n, io_list, b_list) { |
| 1823 | bp->b_flags &= ~(_XBF_DELWRI_Q | XBF_ASYNC | XBF_WRITE_FAIL); |
| 1824 | bp->b_flags |= XBF_WRITE | XBF_ASYNC; |
| 1825 | |
| 1826 | /* |
| 1827 | * we do all Io submission async. This means if we need to wait |
| 1828 | * for IO completion we need to take an extra reference so the |
| 1829 | * buffer is still valid on the other side. |
| 1830 | */ |
| 1831 | if (wait) |
| 1832 | xfs_buf_hold(bp); |
| 1833 | else |
| 1834 | list_del_init(&bp->b_list); |
| 1835 | |
| 1836 | xfs_buf_submit(bp); |
| 1837 | } |
| 1838 | blk_finish_plug(&plug); |
| 1839 | |
| 1840 | return pinned; |
| 1841 | } |
| 1842 | |
| 1843 | /* |
| 1844 | * Write out a buffer list asynchronously. |
| 1845 | * |
| 1846 | * This will take the @buffer_list, write all non-locked and non-pinned buffers |
| 1847 | * out and not wait for I/O completion on any of the buffers. This interface |
| 1848 | * is only safely useable for callers that can track I/O completion by higher |
| 1849 | * level means, e.g. AIL pushing as the @buffer_list is consumed in this |
| 1850 | * function. |
| 1851 | */ |
| 1852 | int |
| 1853 | xfs_buf_delwri_submit_nowait( |
| 1854 | struct list_head *buffer_list) |
| 1855 | { |
| 1856 | LIST_HEAD (io_list); |
| 1857 | return __xfs_buf_delwri_submit(buffer_list, &io_list, false); |
| 1858 | } |
| 1859 | |
| 1860 | /* |
| 1861 | * Write out a buffer list synchronously. |
| 1862 | * |
| 1863 | * This will take the @buffer_list, write all buffers out and wait for I/O |
| 1864 | * completion on all of the buffers. @buffer_list is consumed by the function, |
| 1865 | * so callers must have some other way of tracking buffers if they require such |
| 1866 | * functionality. |
| 1867 | */ |
| 1868 | int |
| 1869 | xfs_buf_delwri_submit( |
| 1870 | struct list_head *buffer_list) |
| 1871 | { |
| 1872 | LIST_HEAD (io_list); |
| 1873 | int error = 0, error2; |
| 1874 | struct xfs_buf *bp; |
| 1875 | |
| 1876 | __xfs_buf_delwri_submit(buffer_list, &io_list, true); |
| 1877 | |
| 1878 | /* Wait for IO to complete. */ |
| 1879 | while (!list_empty(&io_list)) { |
| 1880 | bp = list_first_entry(&io_list, struct xfs_buf, b_list); |
| 1881 | |
| 1882 | list_del_init(&bp->b_list); |
| 1883 | |
| 1884 | /* locking the buffer will wait for async IO completion. */ |
| 1885 | xfs_buf_lock(bp); |
| 1886 | error2 = bp->b_error; |
| 1887 | xfs_buf_relse(bp); |
| 1888 | if (!error) |
| 1889 | error = error2; |
| 1890 | } |
| 1891 | |
| 1892 | return error; |
| 1893 | } |
| 1894 | |
| 1895 | int __init |
| 1896 | xfs_buf_init(void) |
| 1897 | { |
| 1898 | xfs_buf_zone = kmem_zone_init_flags(sizeof(xfs_buf_t), "xfs_buf", |
| 1899 | KM_ZONE_HWALIGN, NULL); |
| 1900 | if (!xfs_buf_zone) |
| 1901 | goto out; |
| 1902 | |
| 1903 | return 0; |
| 1904 | |
| 1905 | out: |
| 1906 | return -ENOMEM; |
| 1907 | } |
| 1908 | |
| 1909 | void |
| 1910 | xfs_buf_terminate(void) |
| 1911 | { |
| 1912 | kmem_zone_destroy(xfs_buf_zone); |
| 1913 | } |