| 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_sb.h" |
| 38 | #include "xfs_inum.h" |
| 39 | #include "xfs_log.h" |
| 40 | #include "xfs_ag.h" |
| 41 | #include "xfs_mount.h" |
| 42 | #include "xfs_trace.h" |
| 43 | |
| 44 | static kmem_zone_t *xfs_buf_zone; |
| 45 | STATIC int xfsbufd(void *); |
| 46 | |
| 47 | static struct workqueue_struct *xfslogd_workqueue; |
| 48 | struct workqueue_struct *xfsdatad_workqueue; |
| 49 | struct workqueue_struct *xfsconvertd_workqueue; |
| 50 | |
| 51 | #ifdef XFS_BUF_LOCK_TRACKING |
| 52 | # define XB_SET_OWNER(bp) ((bp)->b_last_holder = current->pid) |
| 53 | # define XB_CLEAR_OWNER(bp) ((bp)->b_last_holder = -1) |
| 54 | # define XB_GET_OWNER(bp) ((bp)->b_last_holder) |
| 55 | #else |
| 56 | # define XB_SET_OWNER(bp) do { } while (0) |
| 57 | # define XB_CLEAR_OWNER(bp) do { } while (0) |
| 58 | # define XB_GET_OWNER(bp) do { } while (0) |
| 59 | #endif |
| 60 | |
| 61 | #define xb_to_gfp(flags) \ |
| 62 | ((((flags) & XBF_READ_AHEAD) ? __GFP_NORETRY : \ |
| 63 | ((flags) & XBF_DONT_BLOCK) ? GFP_NOFS : GFP_KERNEL) | __GFP_NOWARN) |
| 64 | |
| 65 | #define xb_to_km(flags) \ |
| 66 | (((flags) & XBF_DONT_BLOCK) ? KM_NOFS : KM_SLEEP) |
| 67 | |
| 68 | |
| 69 | static inline int |
| 70 | xfs_buf_is_vmapped( |
| 71 | struct xfs_buf *bp) |
| 72 | { |
| 73 | /* |
| 74 | * Return true if the buffer is vmapped. |
| 75 | * |
| 76 | * The XBF_MAPPED flag is set if the buffer should be mapped, but the |
| 77 | * code is clever enough to know it doesn't have to map a single page, |
| 78 | * so the check has to be both for XBF_MAPPED and bp->b_page_count > 1. |
| 79 | */ |
| 80 | return (bp->b_flags & XBF_MAPPED) && bp->b_page_count > 1; |
| 81 | } |
| 82 | |
| 83 | static inline int |
| 84 | xfs_buf_vmap_len( |
| 85 | struct xfs_buf *bp) |
| 86 | { |
| 87 | return (bp->b_page_count * PAGE_SIZE) - bp->b_offset; |
| 88 | } |
| 89 | |
| 90 | /* |
| 91 | * xfs_buf_lru_add - add a buffer to the LRU. |
| 92 | * |
| 93 | * The LRU takes a new reference to the buffer so that it will only be freed |
| 94 | * once the shrinker takes the buffer off the LRU. |
| 95 | */ |
| 96 | STATIC void |
| 97 | xfs_buf_lru_add( |
| 98 | struct xfs_buf *bp) |
| 99 | { |
| 100 | struct xfs_buftarg *btp = bp->b_target; |
| 101 | |
| 102 | spin_lock(&btp->bt_lru_lock); |
| 103 | if (list_empty(&bp->b_lru)) { |
| 104 | atomic_inc(&bp->b_hold); |
| 105 | list_add_tail(&bp->b_lru, &btp->bt_lru); |
| 106 | btp->bt_lru_nr++; |
| 107 | } |
| 108 | spin_unlock(&btp->bt_lru_lock); |
| 109 | } |
| 110 | |
| 111 | /* |
| 112 | * xfs_buf_lru_del - remove a buffer from the LRU |
| 113 | * |
| 114 | * The unlocked check is safe here because it only occurs when there are not |
| 115 | * b_lru_ref counts left on the inode under the pag->pag_buf_lock. it is there |
| 116 | * to optimise the shrinker removing the buffer from the LRU and calling |
| 117 | * xfs_buf_free(). i.e. it removes an unnecessary round trip on the |
| 118 | * bt_lru_lock. |
| 119 | */ |
| 120 | STATIC void |
| 121 | xfs_buf_lru_del( |
| 122 | struct xfs_buf *bp) |
| 123 | { |
| 124 | struct xfs_buftarg *btp = bp->b_target; |
| 125 | |
| 126 | if (list_empty(&bp->b_lru)) |
| 127 | return; |
| 128 | |
| 129 | spin_lock(&btp->bt_lru_lock); |
| 130 | if (!list_empty(&bp->b_lru)) { |
| 131 | list_del_init(&bp->b_lru); |
| 132 | btp->bt_lru_nr--; |
| 133 | } |
| 134 | spin_unlock(&btp->bt_lru_lock); |
| 135 | } |
| 136 | |
| 137 | /* |
| 138 | * When we mark a buffer stale, we remove the buffer from the LRU and clear the |
| 139 | * b_lru_ref count so that the buffer is freed immediately when the buffer |
| 140 | * reference count falls to zero. If the buffer is already on the LRU, we need |
| 141 | * to remove the reference that LRU holds on the buffer. |
| 142 | * |
| 143 | * This prevents build-up of stale buffers on the LRU. |
| 144 | */ |
| 145 | void |
| 146 | xfs_buf_stale( |
| 147 | struct xfs_buf *bp) |
| 148 | { |
| 149 | bp->b_flags |= XBF_STALE; |
| 150 | xfs_buf_delwri_dequeue(bp); |
| 151 | atomic_set(&(bp)->b_lru_ref, 0); |
| 152 | if (!list_empty(&bp->b_lru)) { |
| 153 | struct xfs_buftarg *btp = bp->b_target; |
| 154 | |
| 155 | spin_lock(&btp->bt_lru_lock); |
| 156 | if (!list_empty(&bp->b_lru)) { |
| 157 | list_del_init(&bp->b_lru); |
| 158 | btp->bt_lru_nr--; |
| 159 | atomic_dec(&bp->b_hold); |
| 160 | } |
| 161 | spin_unlock(&btp->bt_lru_lock); |
| 162 | } |
| 163 | ASSERT(atomic_read(&bp->b_hold) >= 1); |
| 164 | } |
| 165 | |
| 166 | struct xfs_buf * |
| 167 | xfs_buf_alloc( |
| 168 | struct xfs_buftarg *target, |
| 169 | xfs_off_t range_base, |
| 170 | size_t range_length, |
| 171 | xfs_buf_flags_t flags) |
| 172 | { |
| 173 | struct xfs_buf *bp; |
| 174 | |
| 175 | bp = kmem_zone_alloc(xfs_buf_zone, xb_to_km(flags)); |
| 176 | if (unlikely(!bp)) |
| 177 | return NULL; |
| 178 | |
| 179 | /* |
| 180 | * We don't want certain flags to appear in b_flags. |
| 181 | */ |
| 182 | flags &= ~(XBF_LOCK|XBF_MAPPED|XBF_DONT_BLOCK|XBF_READ_AHEAD); |
| 183 | |
| 184 | memset(bp, 0, sizeof(xfs_buf_t)); |
| 185 | atomic_set(&bp->b_hold, 1); |
| 186 | atomic_set(&bp->b_lru_ref, 1); |
| 187 | init_completion(&bp->b_iowait); |
| 188 | INIT_LIST_HEAD(&bp->b_lru); |
| 189 | INIT_LIST_HEAD(&bp->b_list); |
| 190 | RB_CLEAR_NODE(&bp->b_rbnode); |
| 191 | sema_init(&bp->b_sema, 0); /* held, no waiters */ |
| 192 | XB_SET_OWNER(bp); |
| 193 | bp->b_target = target; |
| 194 | bp->b_file_offset = range_base; |
| 195 | /* |
| 196 | * Set buffer_length and count_desired to the same value initially. |
| 197 | * I/O routines should use count_desired, which will be the same in |
| 198 | * most cases but may be reset (e.g. XFS recovery). |
| 199 | */ |
| 200 | bp->b_buffer_length = bp->b_count_desired = range_length; |
| 201 | bp->b_flags = flags; |
| 202 | bp->b_bn = XFS_BUF_DADDR_NULL; |
| 203 | atomic_set(&bp->b_pin_count, 0); |
| 204 | init_waitqueue_head(&bp->b_waiters); |
| 205 | |
| 206 | XFS_STATS_INC(xb_create); |
| 207 | trace_xfs_buf_init(bp, _RET_IP_); |
| 208 | |
| 209 | return bp; |
| 210 | } |
| 211 | |
| 212 | /* |
| 213 | * Allocate a page array capable of holding a specified number |
| 214 | * of pages, and point the page buf at it. |
| 215 | */ |
| 216 | STATIC int |
| 217 | _xfs_buf_get_pages( |
| 218 | xfs_buf_t *bp, |
| 219 | int page_count, |
| 220 | xfs_buf_flags_t flags) |
| 221 | { |
| 222 | /* Make sure that we have a page list */ |
| 223 | if (bp->b_pages == NULL) { |
| 224 | bp->b_offset = xfs_buf_poff(bp->b_file_offset); |
| 225 | bp->b_page_count = page_count; |
| 226 | if (page_count <= XB_PAGES) { |
| 227 | bp->b_pages = bp->b_page_array; |
| 228 | } else { |
| 229 | bp->b_pages = kmem_alloc(sizeof(struct page *) * |
| 230 | page_count, xb_to_km(flags)); |
| 231 | if (bp->b_pages == NULL) |
| 232 | return -ENOMEM; |
| 233 | } |
| 234 | memset(bp->b_pages, 0, sizeof(struct page *) * page_count); |
| 235 | } |
| 236 | return 0; |
| 237 | } |
| 238 | |
| 239 | /* |
| 240 | * Frees b_pages if it was allocated. |
| 241 | */ |
| 242 | STATIC void |
| 243 | _xfs_buf_free_pages( |
| 244 | xfs_buf_t *bp) |
| 245 | { |
| 246 | if (bp->b_pages != bp->b_page_array) { |
| 247 | kmem_free(bp->b_pages); |
| 248 | bp->b_pages = NULL; |
| 249 | } |
| 250 | } |
| 251 | |
| 252 | /* |
| 253 | * Releases the specified buffer. |
| 254 | * |
| 255 | * The modification state of any associated pages is left unchanged. |
| 256 | * The buffer most not be on any hash - use xfs_buf_rele instead for |
| 257 | * hashed and refcounted buffers |
| 258 | */ |
| 259 | void |
| 260 | xfs_buf_free( |
| 261 | xfs_buf_t *bp) |
| 262 | { |
| 263 | trace_xfs_buf_free(bp, _RET_IP_); |
| 264 | |
| 265 | ASSERT(list_empty(&bp->b_lru)); |
| 266 | |
| 267 | if (bp->b_flags & _XBF_PAGES) { |
| 268 | uint i; |
| 269 | |
| 270 | if (xfs_buf_is_vmapped(bp)) |
| 271 | vm_unmap_ram(bp->b_addr - bp->b_offset, |
| 272 | bp->b_page_count); |
| 273 | |
| 274 | for (i = 0; i < bp->b_page_count; i++) { |
| 275 | struct page *page = bp->b_pages[i]; |
| 276 | |
| 277 | __free_page(page); |
| 278 | } |
| 279 | } else if (bp->b_flags & _XBF_KMEM) |
| 280 | kmem_free(bp->b_addr); |
| 281 | _xfs_buf_free_pages(bp); |
| 282 | kmem_zone_free(xfs_buf_zone, bp); |
| 283 | } |
| 284 | |
| 285 | /* |
| 286 | * Allocates all the pages for buffer in question and builds it's page list. |
| 287 | */ |
| 288 | STATIC int |
| 289 | xfs_buf_allocate_memory( |
| 290 | xfs_buf_t *bp, |
| 291 | uint flags) |
| 292 | { |
| 293 | size_t size = bp->b_count_desired; |
| 294 | size_t nbytes, offset; |
| 295 | gfp_t gfp_mask = xb_to_gfp(flags); |
| 296 | unsigned short page_count, i; |
| 297 | xfs_off_t end; |
| 298 | int error; |
| 299 | |
| 300 | /* |
| 301 | * for buffers that are contained within a single page, just allocate |
| 302 | * the memory from the heap - there's no need for the complexity of |
| 303 | * page arrays to keep allocation down to order 0. |
| 304 | */ |
| 305 | if (bp->b_buffer_length < PAGE_SIZE) { |
| 306 | bp->b_addr = kmem_alloc(bp->b_buffer_length, xb_to_km(flags)); |
| 307 | if (!bp->b_addr) { |
| 308 | /* low memory - use alloc_page loop instead */ |
| 309 | goto use_alloc_page; |
| 310 | } |
| 311 | |
| 312 | if (((unsigned long)(bp->b_addr + bp->b_buffer_length - 1) & |
| 313 | PAGE_MASK) != |
| 314 | ((unsigned long)bp->b_addr & PAGE_MASK)) { |
| 315 | /* b_addr spans two pages - use alloc_page instead */ |
| 316 | kmem_free(bp->b_addr); |
| 317 | bp->b_addr = NULL; |
| 318 | goto use_alloc_page; |
| 319 | } |
| 320 | bp->b_offset = offset_in_page(bp->b_addr); |
| 321 | bp->b_pages = bp->b_page_array; |
| 322 | bp->b_pages[0] = virt_to_page(bp->b_addr); |
| 323 | bp->b_page_count = 1; |
| 324 | bp->b_flags |= XBF_MAPPED | _XBF_KMEM; |
| 325 | return 0; |
| 326 | } |
| 327 | |
| 328 | use_alloc_page: |
| 329 | end = bp->b_file_offset + bp->b_buffer_length; |
| 330 | page_count = xfs_buf_btoc(end) - xfs_buf_btoct(bp->b_file_offset); |
| 331 | error = _xfs_buf_get_pages(bp, page_count, flags); |
| 332 | if (unlikely(error)) |
| 333 | return error; |
| 334 | |
| 335 | offset = bp->b_offset; |
| 336 | bp->b_flags |= _XBF_PAGES; |
| 337 | |
| 338 | for (i = 0; i < bp->b_page_count; i++) { |
| 339 | struct page *page; |
| 340 | uint retries = 0; |
| 341 | retry: |
| 342 | page = alloc_page(gfp_mask); |
| 343 | if (unlikely(page == NULL)) { |
| 344 | if (flags & XBF_READ_AHEAD) { |
| 345 | bp->b_page_count = i; |
| 346 | error = ENOMEM; |
| 347 | goto out_free_pages; |
| 348 | } |
| 349 | |
| 350 | /* |
| 351 | * This could deadlock. |
| 352 | * |
| 353 | * But until all the XFS lowlevel code is revamped to |
| 354 | * handle buffer allocation failures we can't do much. |
| 355 | */ |
| 356 | if (!(++retries % 100)) |
| 357 | xfs_err(NULL, |
| 358 | "possible memory allocation deadlock in %s (mode:0x%x)", |
| 359 | __func__, gfp_mask); |
| 360 | |
| 361 | XFS_STATS_INC(xb_page_retries); |
| 362 | congestion_wait(BLK_RW_ASYNC, HZ/50); |
| 363 | goto retry; |
| 364 | } |
| 365 | |
| 366 | XFS_STATS_INC(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 | bp->b_flags |= XBF_MAPPED; |
| 394 | } else if (flags & XBF_MAPPED) { |
| 395 | int retried = 0; |
| 396 | |
| 397 | do { |
| 398 | bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count, |
| 399 | -1, PAGE_KERNEL); |
| 400 | if (bp->b_addr) |
| 401 | break; |
| 402 | vm_unmap_aliases(); |
| 403 | } while (retried++ <= 1); |
| 404 | |
| 405 | if (!bp->b_addr) |
| 406 | return -ENOMEM; |
| 407 | bp->b_addr += bp->b_offset; |
| 408 | bp->b_flags |= XBF_MAPPED; |
| 409 | } |
| 410 | |
| 411 | return 0; |
| 412 | } |
| 413 | |
| 414 | /* |
| 415 | * Finding and Reading Buffers |
| 416 | */ |
| 417 | |
| 418 | /* |
| 419 | * Look up, and creates if absent, a lockable buffer for |
| 420 | * a given range of an inode. The buffer is returned |
| 421 | * locked. No I/O is implied by this call. |
| 422 | */ |
| 423 | xfs_buf_t * |
| 424 | _xfs_buf_find( |
| 425 | xfs_buftarg_t *btp, /* block device target */ |
| 426 | xfs_off_t ioff, /* starting offset of range */ |
| 427 | size_t isize, /* length of range */ |
| 428 | xfs_buf_flags_t flags, |
| 429 | xfs_buf_t *new_bp) |
| 430 | { |
| 431 | xfs_off_t range_base; |
| 432 | size_t range_length; |
| 433 | struct xfs_perag *pag; |
| 434 | struct rb_node **rbp; |
| 435 | struct rb_node *parent; |
| 436 | xfs_buf_t *bp; |
| 437 | |
| 438 | range_base = (ioff << BBSHIFT); |
| 439 | range_length = (isize << BBSHIFT); |
| 440 | |
| 441 | /* Check for IOs smaller than the sector size / not sector aligned */ |
| 442 | ASSERT(!(range_length < (1 << btp->bt_sshift))); |
| 443 | ASSERT(!(range_base & (xfs_off_t)btp->bt_smask)); |
| 444 | |
| 445 | /* get tree root */ |
| 446 | pag = xfs_perag_get(btp->bt_mount, |
| 447 | xfs_daddr_to_agno(btp->bt_mount, ioff)); |
| 448 | |
| 449 | /* walk tree */ |
| 450 | spin_lock(&pag->pag_buf_lock); |
| 451 | rbp = &pag->pag_buf_tree.rb_node; |
| 452 | parent = NULL; |
| 453 | bp = NULL; |
| 454 | while (*rbp) { |
| 455 | parent = *rbp; |
| 456 | bp = rb_entry(parent, struct xfs_buf, b_rbnode); |
| 457 | |
| 458 | if (range_base < bp->b_file_offset) |
| 459 | rbp = &(*rbp)->rb_left; |
| 460 | else if (range_base > bp->b_file_offset) |
| 461 | rbp = &(*rbp)->rb_right; |
| 462 | else { |
| 463 | /* |
| 464 | * found a block offset match. If the range doesn't |
| 465 | * match, the only way this is allowed is if the buffer |
| 466 | * in the cache is stale and the transaction that made |
| 467 | * it stale has not yet committed. i.e. we are |
| 468 | * reallocating a busy extent. Skip this buffer and |
| 469 | * continue searching to the right for an exact match. |
| 470 | */ |
| 471 | if (bp->b_buffer_length != range_length) { |
| 472 | ASSERT(bp->b_flags & XBF_STALE); |
| 473 | rbp = &(*rbp)->rb_right; |
| 474 | continue; |
| 475 | } |
| 476 | atomic_inc(&bp->b_hold); |
| 477 | goto found; |
| 478 | } |
| 479 | } |
| 480 | |
| 481 | /* No match found */ |
| 482 | if (new_bp) { |
| 483 | rb_link_node(&new_bp->b_rbnode, parent, rbp); |
| 484 | rb_insert_color(&new_bp->b_rbnode, &pag->pag_buf_tree); |
| 485 | /* the buffer keeps the perag reference until it is freed */ |
| 486 | new_bp->b_pag = pag; |
| 487 | spin_unlock(&pag->pag_buf_lock); |
| 488 | } else { |
| 489 | XFS_STATS_INC(xb_miss_locked); |
| 490 | spin_unlock(&pag->pag_buf_lock); |
| 491 | xfs_perag_put(pag); |
| 492 | } |
| 493 | return new_bp; |
| 494 | |
| 495 | found: |
| 496 | spin_unlock(&pag->pag_buf_lock); |
| 497 | xfs_perag_put(pag); |
| 498 | |
| 499 | if (!xfs_buf_trylock(bp)) { |
| 500 | if (flags & XBF_TRYLOCK) { |
| 501 | xfs_buf_rele(bp); |
| 502 | XFS_STATS_INC(xb_busy_locked); |
| 503 | return NULL; |
| 504 | } |
| 505 | xfs_buf_lock(bp); |
| 506 | XFS_STATS_INC(xb_get_locked_waited); |
| 507 | } |
| 508 | |
| 509 | /* |
| 510 | * if the buffer is stale, clear all the external state associated with |
| 511 | * it. We need to keep flags such as how we allocated the buffer memory |
| 512 | * intact here. |
| 513 | */ |
| 514 | if (bp->b_flags & XBF_STALE) { |
| 515 | ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0); |
| 516 | bp->b_flags &= XBF_MAPPED | _XBF_KMEM | _XBF_PAGES; |
| 517 | } |
| 518 | |
| 519 | trace_xfs_buf_find(bp, flags, _RET_IP_); |
| 520 | XFS_STATS_INC(xb_get_locked); |
| 521 | return bp; |
| 522 | } |
| 523 | |
| 524 | /* |
| 525 | * Assembles a buffer covering the specified range. The code is optimised for |
| 526 | * cache hits, as metadata intensive workloads will see 3 orders of magnitude |
| 527 | * more hits than misses. |
| 528 | */ |
| 529 | struct xfs_buf * |
| 530 | xfs_buf_get( |
| 531 | xfs_buftarg_t *target,/* target for buffer */ |
| 532 | xfs_off_t ioff, /* starting offset of range */ |
| 533 | size_t isize, /* length of range */ |
| 534 | xfs_buf_flags_t flags) |
| 535 | { |
| 536 | struct xfs_buf *bp; |
| 537 | struct xfs_buf *new_bp; |
| 538 | int error = 0; |
| 539 | |
| 540 | bp = _xfs_buf_find(target, ioff, isize, flags, NULL); |
| 541 | if (likely(bp)) |
| 542 | goto found; |
| 543 | |
| 544 | new_bp = xfs_buf_alloc(target, ioff << BBSHIFT, isize << BBSHIFT, |
| 545 | flags); |
| 546 | if (unlikely(!new_bp)) |
| 547 | return NULL; |
| 548 | |
| 549 | bp = _xfs_buf_find(target, ioff, isize, flags, new_bp); |
| 550 | if (!bp) { |
| 551 | kmem_zone_free(xfs_buf_zone, new_bp); |
| 552 | return NULL; |
| 553 | } |
| 554 | |
| 555 | if (bp == new_bp) { |
| 556 | error = xfs_buf_allocate_memory(bp, flags); |
| 557 | if (error) |
| 558 | goto no_buffer; |
| 559 | } else |
| 560 | kmem_zone_free(xfs_buf_zone, new_bp); |
| 561 | |
| 562 | /* |
| 563 | * Now we have a workable buffer, fill in the block number so |
| 564 | * that we can do IO on it. |
| 565 | */ |
| 566 | bp->b_bn = ioff; |
| 567 | bp->b_count_desired = bp->b_buffer_length; |
| 568 | |
| 569 | found: |
| 570 | if (!(bp->b_flags & XBF_MAPPED)) { |
| 571 | error = _xfs_buf_map_pages(bp, flags); |
| 572 | if (unlikely(error)) { |
| 573 | xfs_warn(target->bt_mount, |
| 574 | "%s: failed to map pages\n", __func__); |
| 575 | goto no_buffer; |
| 576 | } |
| 577 | } |
| 578 | |
| 579 | XFS_STATS_INC(xb_get); |
| 580 | trace_xfs_buf_get(bp, flags, _RET_IP_); |
| 581 | return bp; |
| 582 | |
| 583 | no_buffer: |
| 584 | if (flags & (XBF_LOCK | XBF_TRYLOCK)) |
| 585 | xfs_buf_unlock(bp); |
| 586 | xfs_buf_rele(bp); |
| 587 | return NULL; |
| 588 | } |
| 589 | |
| 590 | STATIC int |
| 591 | _xfs_buf_read( |
| 592 | xfs_buf_t *bp, |
| 593 | xfs_buf_flags_t flags) |
| 594 | { |
| 595 | int status; |
| 596 | |
| 597 | ASSERT(!(flags & (XBF_DELWRI|XBF_WRITE))); |
| 598 | ASSERT(bp->b_bn != XFS_BUF_DADDR_NULL); |
| 599 | |
| 600 | bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_DELWRI | XBF_READ_AHEAD); |
| 601 | bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD); |
| 602 | |
| 603 | status = xfs_buf_iorequest(bp); |
| 604 | if (status || bp->b_error || (flags & XBF_ASYNC)) |
| 605 | return status; |
| 606 | return xfs_buf_iowait(bp); |
| 607 | } |
| 608 | |
| 609 | xfs_buf_t * |
| 610 | xfs_buf_read( |
| 611 | xfs_buftarg_t *target, |
| 612 | xfs_off_t ioff, |
| 613 | size_t isize, |
| 614 | xfs_buf_flags_t flags) |
| 615 | { |
| 616 | xfs_buf_t *bp; |
| 617 | |
| 618 | flags |= XBF_READ; |
| 619 | |
| 620 | bp = xfs_buf_get(target, ioff, isize, flags); |
| 621 | if (bp) { |
| 622 | trace_xfs_buf_read(bp, flags, _RET_IP_); |
| 623 | |
| 624 | if (!XFS_BUF_ISDONE(bp)) { |
| 625 | XFS_STATS_INC(xb_get_read); |
| 626 | _xfs_buf_read(bp, flags); |
| 627 | } else if (flags & XBF_ASYNC) { |
| 628 | /* |
| 629 | * Read ahead call which is already satisfied, |
| 630 | * drop the buffer |
| 631 | */ |
| 632 | goto no_buffer; |
| 633 | } else { |
| 634 | /* We do not want read in the flags */ |
| 635 | bp->b_flags &= ~XBF_READ; |
| 636 | } |
| 637 | } |
| 638 | |
| 639 | return bp; |
| 640 | |
| 641 | no_buffer: |
| 642 | if (flags & (XBF_LOCK | XBF_TRYLOCK)) |
| 643 | xfs_buf_unlock(bp); |
| 644 | xfs_buf_rele(bp); |
| 645 | return NULL; |
| 646 | } |
| 647 | |
| 648 | /* |
| 649 | * If we are not low on memory then do the readahead in a deadlock |
| 650 | * safe manner. |
| 651 | */ |
| 652 | void |
| 653 | xfs_buf_readahead( |
| 654 | xfs_buftarg_t *target, |
| 655 | xfs_off_t ioff, |
| 656 | size_t isize) |
| 657 | { |
| 658 | if (bdi_read_congested(target->bt_bdi)) |
| 659 | return; |
| 660 | |
| 661 | xfs_buf_read(target, ioff, isize, |
| 662 | XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD|XBF_DONT_BLOCK); |
| 663 | } |
| 664 | |
| 665 | /* |
| 666 | * Read an uncached buffer from disk. Allocates and returns a locked |
| 667 | * buffer containing the disk contents or nothing. |
| 668 | */ |
| 669 | struct xfs_buf * |
| 670 | xfs_buf_read_uncached( |
| 671 | struct xfs_mount *mp, |
| 672 | struct xfs_buftarg *target, |
| 673 | xfs_daddr_t daddr, |
| 674 | size_t length, |
| 675 | int flags) |
| 676 | { |
| 677 | xfs_buf_t *bp; |
| 678 | int error; |
| 679 | |
| 680 | bp = xfs_buf_get_uncached(target, length, flags); |
| 681 | if (!bp) |
| 682 | return NULL; |
| 683 | |
| 684 | /* set up the buffer for a read IO */ |
| 685 | XFS_BUF_SET_ADDR(bp, daddr); |
| 686 | XFS_BUF_READ(bp); |
| 687 | |
| 688 | xfsbdstrat(mp, bp); |
| 689 | error = xfs_buf_iowait(bp); |
| 690 | if (error || bp->b_error) { |
| 691 | xfs_buf_relse(bp); |
| 692 | return NULL; |
| 693 | } |
| 694 | return bp; |
| 695 | } |
| 696 | |
| 697 | /* |
| 698 | * Return a buffer allocated as an empty buffer and associated to external |
| 699 | * memory via xfs_buf_associate_memory() back to it's empty state. |
| 700 | */ |
| 701 | void |
| 702 | xfs_buf_set_empty( |
| 703 | struct xfs_buf *bp, |
| 704 | size_t len) |
| 705 | { |
| 706 | if (bp->b_pages) |
| 707 | _xfs_buf_free_pages(bp); |
| 708 | |
| 709 | bp->b_pages = NULL; |
| 710 | bp->b_page_count = 0; |
| 711 | bp->b_addr = NULL; |
| 712 | bp->b_file_offset = 0; |
| 713 | bp->b_buffer_length = bp->b_count_desired = len; |
| 714 | bp->b_bn = XFS_BUF_DADDR_NULL; |
| 715 | bp->b_flags &= ~XBF_MAPPED; |
| 716 | } |
| 717 | |
| 718 | static inline struct page * |
| 719 | mem_to_page( |
| 720 | void *addr) |
| 721 | { |
| 722 | if ((!is_vmalloc_addr(addr))) { |
| 723 | return virt_to_page(addr); |
| 724 | } else { |
| 725 | return vmalloc_to_page(addr); |
| 726 | } |
| 727 | } |
| 728 | |
| 729 | int |
| 730 | xfs_buf_associate_memory( |
| 731 | xfs_buf_t *bp, |
| 732 | void *mem, |
| 733 | size_t len) |
| 734 | { |
| 735 | int rval; |
| 736 | int i = 0; |
| 737 | unsigned long pageaddr; |
| 738 | unsigned long offset; |
| 739 | size_t buflen; |
| 740 | int page_count; |
| 741 | |
| 742 | pageaddr = (unsigned long)mem & PAGE_MASK; |
| 743 | offset = (unsigned long)mem - pageaddr; |
| 744 | buflen = PAGE_ALIGN(len + offset); |
| 745 | page_count = buflen >> PAGE_SHIFT; |
| 746 | |
| 747 | /* Free any previous set of page pointers */ |
| 748 | if (bp->b_pages) |
| 749 | _xfs_buf_free_pages(bp); |
| 750 | |
| 751 | bp->b_pages = NULL; |
| 752 | bp->b_addr = mem; |
| 753 | |
| 754 | rval = _xfs_buf_get_pages(bp, page_count, XBF_DONT_BLOCK); |
| 755 | if (rval) |
| 756 | return rval; |
| 757 | |
| 758 | bp->b_offset = offset; |
| 759 | |
| 760 | for (i = 0; i < bp->b_page_count; i++) { |
| 761 | bp->b_pages[i] = mem_to_page((void *)pageaddr); |
| 762 | pageaddr += PAGE_SIZE; |
| 763 | } |
| 764 | |
| 765 | bp->b_count_desired = len; |
| 766 | bp->b_buffer_length = buflen; |
| 767 | bp->b_flags |= XBF_MAPPED; |
| 768 | |
| 769 | return 0; |
| 770 | } |
| 771 | |
| 772 | xfs_buf_t * |
| 773 | xfs_buf_get_uncached( |
| 774 | struct xfs_buftarg *target, |
| 775 | size_t len, |
| 776 | int flags) |
| 777 | { |
| 778 | unsigned long page_count = PAGE_ALIGN(len) >> PAGE_SHIFT; |
| 779 | int error, i; |
| 780 | xfs_buf_t *bp; |
| 781 | |
| 782 | bp = xfs_buf_alloc(target, 0, len, 0); |
| 783 | if (unlikely(bp == NULL)) |
| 784 | goto fail; |
| 785 | |
| 786 | error = _xfs_buf_get_pages(bp, page_count, 0); |
| 787 | if (error) |
| 788 | goto fail_free_buf; |
| 789 | |
| 790 | for (i = 0; i < page_count; i++) { |
| 791 | bp->b_pages[i] = alloc_page(xb_to_gfp(flags)); |
| 792 | if (!bp->b_pages[i]) |
| 793 | goto fail_free_mem; |
| 794 | } |
| 795 | bp->b_flags |= _XBF_PAGES; |
| 796 | |
| 797 | error = _xfs_buf_map_pages(bp, XBF_MAPPED); |
| 798 | if (unlikely(error)) { |
| 799 | xfs_warn(target->bt_mount, |
| 800 | "%s: failed to map pages\n", __func__); |
| 801 | goto fail_free_mem; |
| 802 | } |
| 803 | |
| 804 | trace_xfs_buf_get_uncached(bp, _RET_IP_); |
| 805 | return bp; |
| 806 | |
| 807 | fail_free_mem: |
| 808 | while (--i >= 0) |
| 809 | __free_page(bp->b_pages[i]); |
| 810 | _xfs_buf_free_pages(bp); |
| 811 | fail_free_buf: |
| 812 | kmem_zone_free(xfs_buf_zone, bp); |
| 813 | fail: |
| 814 | return NULL; |
| 815 | } |
| 816 | |
| 817 | /* |
| 818 | * Increment reference count on buffer, to hold the buffer concurrently |
| 819 | * with another thread which may release (free) the buffer asynchronously. |
| 820 | * Must hold the buffer already to call this function. |
| 821 | */ |
| 822 | void |
| 823 | xfs_buf_hold( |
| 824 | xfs_buf_t *bp) |
| 825 | { |
| 826 | trace_xfs_buf_hold(bp, _RET_IP_); |
| 827 | atomic_inc(&bp->b_hold); |
| 828 | } |
| 829 | |
| 830 | /* |
| 831 | * Releases a hold on the specified buffer. If the |
| 832 | * the hold count is 1, calls xfs_buf_free. |
| 833 | */ |
| 834 | void |
| 835 | xfs_buf_rele( |
| 836 | xfs_buf_t *bp) |
| 837 | { |
| 838 | struct xfs_perag *pag = bp->b_pag; |
| 839 | |
| 840 | trace_xfs_buf_rele(bp, _RET_IP_); |
| 841 | |
| 842 | if (!pag) { |
| 843 | ASSERT(list_empty(&bp->b_lru)); |
| 844 | ASSERT(RB_EMPTY_NODE(&bp->b_rbnode)); |
| 845 | if (atomic_dec_and_test(&bp->b_hold)) |
| 846 | xfs_buf_free(bp); |
| 847 | return; |
| 848 | } |
| 849 | |
| 850 | ASSERT(!RB_EMPTY_NODE(&bp->b_rbnode)); |
| 851 | |
| 852 | ASSERT(atomic_read(&bp->b_hold) > 0); |
| 853 | if (atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock)) { |
| 854 | if (!(bp->b_flags & XBF_STALE) && |
| 855 | atomic_read(&bp->b_lru_ref)) { |
| 856 | xfs_buf_lru_add(bp); |
| 857 | spin_unlock(&pag->pag_buf_lock); |
| 858 | } else { |
| 859 | xfs_buf_lru_del(bp); |
| 860 | ASSERT(!(bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q))); |
| 861 | rb_erase(&bp->b_rbnode, &pag->pag_buf_tree); |
| 862 | spin_unlock(&pag->pag_buf_lock); |
| 863 | xfs_perag_put(pag); |
| 864 | xfs_buf_free(bp); |
| 865 | } |
| 866 | } |
| 867 | } |
| 868 | |
| 869 | |
| 870 | /* |
| 871 | * Lock a buffer object, if it is not already locked. |
| 872 | * |
| 873 | * If we come across a stale, pinned, locked buffer, we know that we are |
| 874 | * being asked to lock a buffer that has been reallocated. Because it is |
| 875 | * pinned, we know that the log has not been pushed to disk and hence it |
| 876 | * will still be locked. Rather than continuing to have trylock attempts |
| 877 | * fail until someone else pushes the log, push it ourselves before |
| 878 | * returning. This means that the xfsaild will not get stuck trying |
| 879 | * to push on stale inode buffers. |
| 880 | */ |
| 881 | int |
| 882 | xfs_buf_trylock( |
| 883 | struct xfs_buf *bp) |
| 884 | { |
| 885 | int locked; |
| 886 | |
| 887 | locked = down_trylock(&bp->b_sema) == 0; |
| 888 | if (locked) |
| 889 | XB_SET_OWNER(bp); |
| 890 | else if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE)) |
| 891 | xfs_log_force(bp->b_target->bt_mount, 0); |
| 892 | |
| 893 | trace_xfs_buf_trylock(bp, _RET_IP_); |
| 894 | return locked; |
| 895 | } |
| 896 | |
| 897 | /* |
| 898 | * Lock a buffer object. |
| 899 | * |
| 900 | * If we come across a stale, pinned, locked buffer, we know that we |
| 901 | * are being asked to lock a buffer that has been reallocated. Because |
| 902 | * it is pinned, we know that the log has not been pushed to disk and |
| 903 | * hence it will still be locked. Rather than sleeping until someone |
| 904 | * else pushes the log, push it ourselves before trying to get the lock. |
| 905 | */ |
| 906 | void |
| 907 | xfs_buf_lock( |
| 908 | struct xfs_buf *bp) |
| 909 | { |
| 910 | trace_xfs_buf_lock(bp, _RET_IP_); |
| 911 | |
| 912 | if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE)) |
| 913 | xfs_log_force(bp->b_target->bt_mount, 0); |
| 914 | down(&bp->b_sema); |
| 915 | XB_SET_OWNER(bp); |
| 916 | |
| 917 | trace_xfs_buf_lock_done(bp, _RET_IP_); |
| 918 | } |
| 919 | |
| 920 | /* |
| 921 | * Releases the lock on the buffer object. |
| 922 | * If the buffer is marked delwri but is not queued, do so before we |
| 923 | * unlock the buffer as we need to set flags correctly. We also need to |
| 924 | * take a reference for the delwri queue because the unlocker is going to |
| 925 | * drop their's and they don't know we just queued it. |
| 926 | */ |
| 927 | void |
| 928 | xfs_buf_unlock( |
| 929 | struct xfs_buf *bp) |
| 930 | { |
| 931 | XB_CLEAR_OWNER(bp); |
| 932 | up(&bp->b_sema); |
| 933 | |
| 934 | trace_xfs_buf_unlock(bp, _RET_IP_); |
| 935 | } |
| 936 | |
| 937 | STATIC void |
| 938 | xfs_buf_wait_unpin( |
| 939 | xfs_buf_t *bp) |
| 940 | { |
| 941 | DECLARE_WAITQUEUE (wait, current); |
| 942 | |
| 943 | if (atomic_read(&bp->b_pin_count) == 0) |
| 944 | return; |
| 945 | |
| 946 | add_wait_queue(&bp->b_waiters, &wait); |
| 947 | for (;;) { |
| 948 | set_current_state(TASK_UNINTERRUPTIBLE); |
| 949 | if (atomic_read(&bp->b_pin_count) == 0) |
| 950 | break; |
| 951 | io_schedule(); |
| 952 | } |
| 953 | remove_wait_queue(&bp->b_waiters, &wait); |
| 954 | set_current_state(TASK_RUNNING); |
| 955 | } |
| 956 | |
| 957 | /* |
| 958 | * Buffer Utility Routines |
| 959 | */ |
| 960 | |
| 961 | STATIC void |
| 962 | xfs_buf_iodone_work( |
| 963 | struct work_struct *work) |
| 964 | { |
| 965 | xfs_buf_t *bp = |
| 966 | container_of(work, xfs_buf_t, b_iodone_work); |
| 967 | |
| 968 | if (bp->b_iodone) |
| 969 | (*(bp->b_iodone))(bp); |
| 970 | else if (bp->b_flags & XBF_ASYNC) |
| 971 | xfs_buf_relse(bp); |
| 972 | } |
| 973 | |
| 974 | void |
| 975 | xfs_buf_ioend( |
| 976 | xfs_buf_t *bp, |
| 977 | int schedule) |
| 978 | { |
| 979 | trace_xfs_buf_iodone(bp, _RET_IP_); |
| 980 | |
| 981 | bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD); |
| 982 | if (bp->b_error == 0) |
| 983 | bp->b_flags |= XBF_DONE; |
| 984 | |
| 985 | if ((bp->b_iodone) || (bp->b_flags & XBF_ASYNC)) { |
| 986 | if (schedule) { |
| 987 | INIT_WORK(&bp->b_iodone_work, xfs_buf_iodone_work); |
| 988 | queue_work(xfslogd_workqueue, &bp->b_iodone_work); |
| 989 | } else { |
| 990 | xfs_buf_iodone_work(&bp->b_iodone_work); |
| 991 | } |
| 992 | } else { |
| 993 | complete(&bp->b_iowait); |
| 994 | } |
| 995 | } |
| 996 | |
| 997 | void |
| 998 | xfs_buf_ioerror( |
| 999 | xfs_buf_t *bp, |
| 1000 | int error) |
| 1001 | { |
| 1002 | ASSERT(error >= 0 && error <= 0xffff); |
| 1003 | bp->b_error = (unsigned short)error; |
| 1004 | trace_xfs_buf_ioerror(bp, error, _RET_IP_); |
| 1005 | } |
| 1006 | |
| 1007 | void |
| 1008 | xfs_buf_ioerror_alert( |
| 1009 | struct xfs_buf *bp, |
| 1010 | const char *func) |
| 1011 | { |
| 1012 | xfs_alert(bp->b_target->bt_mount, |
| 1013 | "metadata I/O error: block 0x%llx (\"%s\") error %d buf count %zd", |
| 1014 | (__uint64_t)XFS_BUF_ADDR(bp), func, |
| 1015 | bp->b_error, XFS_BUF_COUNT(bp)); |
| 1016 | } |
| 1017 | |
| 1018 | int |
| 1019 | xfs_bwrite( |
| 1020 | struct xfs_buf *bp) |
| 1021 | { |
| 1022 | int error; |
| 1023 | |
| 1024 | bp->b_flags |= XBF_WRITE; |
| 1025 | bp->b_flags &= ~(XBF_ASYNC | XBF_READ); |
| 1026 | |
| 1027 | xfs_buf_delwri_dequeue(bp); |
| 1028 | xfs_bdstrat_cb(bp); |
| 1029 | |
| 1030 | error = xfs_buf_iowait(bp); |
| 1031 | if (error) { |
| 1032 | xfs_force_shutdown(bp->b_target->bt_mount, |
| 1033 | SHUTDOWN_META_IO_ERROR); |
| 1034 | } |
| 1035 | return error; |
| 1036 | } |
| 1037 | |
| 1038 | /* |
| 1039 | * Called when we want to stop a buffer from getting written or read. |
| 1040 | * We attach the EIO error, muck with its flags, and call xfs_buf_ioend |
| 1041 | * so that the proper iodone callbacks get called. |
| 1042 | */ |
| 1043 | STATIC int |
| 1044 | xfs_bioerror( |
| 1045 | xfs_buf_t *bp) |
| 1046 | { |
| 1047 | #ifdef XFSERRORDEBUG |
| 1048 | ASSERT(XFS_BUF_ISREAD(bp) || bp->b_iodone); |
| 1049 | #endif |
| 1050 | |
| 1051 | /* |
| 1052 | * No need to wait until the buffer is unpinned, we aren't flushing it. |
| 1053 | */ |
| 1054 | xfs_buf_ioerror(bp, EIO); |
| 1055 | |
| 1056 | /* |
| 1057 | * We're calling xfs_buf_ioend, so delete XBF_DONE flag. |
| 1058 | */ |
| 1059 | XFS_BUF_UNREAD(bp); |
| 1060 | XFS_BUF_UNDONE(bp); |
| 1061 | xfs_buf_stale(bp); |
| 1062 | |
| 1063 | xfs_buf_ioend(bp, 0); |
| 1064 | |
| 1065 | return EIO; |
| 1066 | } |
| 1067 | |
| 1068 | /* |
| 1069 | * Same as xfs_bioerror, except that we are releasing the buffer |
| 1070 | * here ourselves, and avoiding the xfs_buf_ioend call. |
| 1071 | * This is meant for userdata errors; metadata bufs come with |
| 1072 | * iodone functions attached, so that we can track down errors. |
| 1073 | */ |
| 1074 | STATIC int |
| 1075 | xfs_bioerror_relse( |
| 1076 | struct xfs_buf *bp) |
| 1077 | { |
| 1078 | int64_t fl = bp->b_flags; |
| 1079 | /* |
| 1080 | * No need to wait until the buffer is unpinned. |
| 1081 | * We aren't flushing it. |
| 1082 | * |
| 1083 | * chunkhold expects B_DONE to be set, whether |
| 1084 | * we actually finish the I/O or not. We don't want to |
| 1085 | * change that interface. |
| 1086 | */ |
| 1087 | XFS_BUF_UNREAD(bp); |
| 1088 | XFS_BUF_DONE(bp); |
| 1089 | xfs_buf_stale(bp); |
| 1090 | bp->b_iodone = NULL; |
| 1091 | if (!(fl & XBF_ASYNC)) { |
| 1092 | /* |
| 1093 | * Mark b_error and B_ERROR _both_. |
| 1094 | * Lot's of chunkcache code assumes that. |
| 1095 | * There's no reason to mark error for |
| 1096 | * ASYNC buffers. |
| 1097 | */ |
| 1098 | xfs_buf_ioerror(bp, EIO); |
| 1099 | complete(&bp->b_iowait); |
| 1100 | } else { |
| 1101 | xfs_buf_relse(bp); |
| 1102 | } |
| 1103 | |
| 1104 | return EIO; |
| 1105 | } |
| 1106 | |
| 1107 | |
| 1108 | /* |
| 1109 | * All xfs metadata buffers except log state machine buffers |
| 1110 | * get this attached as their b_bdstrat callback function. |
| 1111 | * This is so that we can catch a buffer |
| 1112 | * after prematurely unpinning it to forcibly shutdown the filesystem. |
| 1113 | */ |
| 1114 | int |
| 1115 | xfs_bdstrat_cb( |
| 1116 | struct xfs_buf *bp) |
| 1117 | { |
| 1118 | if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) { |
| 1119 | trace_xfs_bdstrat_shut(bp, _RET_IP_); |
| 1120 | /* |
| 1121 | * Metadata write that didn't get logged but |
| 1122 | * written delayed anyway. These aren't associated |
| 1123 | * with a transaction, and can be ignored. |
| 1124 | */ |
| 1125 | if (!bp->b_iodone && !XFS_BUF_ISREAD(bp)) |
| 1126 | return xfs_bioerror_relse(bp); |
| 1127 | else |
| 1128 | return xfs_bioerror(bp); |
| 1129 | } |
| 1130 | |
| 1131 | xfs_buf_iorequest(bp); |
| 1132 | return 0; |
| 1133 | } |
| 1134 | |
| 1135 | /* |
| 1136 | * Wrapper around bdstrat so that we can stop data from going to disk in case |
| 1137 | * we are shutting down the filesystem. Typically user data goes thru this |
| 1138 | * path; one of the exceptions is the superblock. |
| 1139 | */ |
| 1140 | void |
| 1141 | xfsbdstrat( |
| 1142 | struct xfs_mount *mp, |
| 1143 | struct xfs_buf *bp) |
| 1144 | { |
| 1145 | if (XFS_FORCED_SHUTDOWN(mp)) { |
| 1146 | trace_xfs_bdstrat_shut(bp, _RET_IP_); |
| 1147 | xfs_bioerror_relse(bp); |
| 1148 | return; |
| 1149 | } |
| 1150 | |
| 1151 | xfs_buf_iorequest(bp); |
| 1152 | } |
| 1153 | |
| 1154 | STATIC void |
| 1155 | _xfs_buf_ioend( |
| 1156 | xfs_buf_t *bp, |
| 1157 | int schedule) |
| 1158 | { |
| 1159 | if (atomic_dec_and_test(&bp->b_io_remaining) == 1) |
| 1160 | xfs_buf_ioend(bp, schedule); |
| 1161 | } |
| 1162 | |
| 1163 | STATIC void |
| 1164 | xfs_buf_bio_end_io( |
| 1165 | struct bio *bio, |
| 1166 | int error) |
| 1167 | { |
| 1168 | xfs_buf_t *bp = (xfs_buf_t *)bio->bi_private; |
| 1169 | |
| 1170 | xfs_buf_ioerror(bp, -error); |
| 1171 | |
| 1172 | if (!error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ)) |
| 1173 | invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp)); |
| 1174 | |
| 1175 | _xfs_buf_ioend(bp, 1); |
| 1176 | bio_put(bio); |
| 1177 | } |
| 1178 | |
| 1179 | STATIC void |
| 1180 | _xfs_buf_ioapply( |
| 1181 | xfs_buf_t *bp) |
| 1182 | { |
| 1183 | int rw, map_i, total_nr_pages, nr_pages; |
| 1184 | struct bio *bio; |
| 1185 | int offset = bp->b_offset; |
| 1186 | int size = bp->b_count_desired; |
| 1187 | sector_t sector = bp->b_bn; |
| 1188 | |
| 1189 | total_nr_pages = bp->b_page_count; |
| 1190 | map_i = 0; |
| 1191 | |
| 1192 | if (bp->b_flags & XBF_WRITE) { |
| 1193 | if (bp->b_flags & XBF_SYNCIO) |
| 1194 | rw = WRITE_SYNC; |
| 1195 | else |
| 1196 | rw = WRITE; |
| 1197 | if (bp->b_flags & XBF_FUA) |
| 1198 | rw |= REQ_FUA; |
| 1199 | if (bp->b_flags & XBF_FLUSH) |
| 1200 | rw |= REQ_FLUSH; |
| 1201 | } else if (bp->b_flags & XBF_READ_AHEAD) { |
| 1202 | rw = READA; |
| 1203 | } else { |
| 1204 | rw = READ; |
| 1205 | } |
| 1206 | |
| 1207 | /* we only use the buffer cache for meta-data */ |
| 1208 | rw |= REQ_META; |
| 1209 | |
| 1210 | next_chunk: |
| 1211 | atomic_inc(&bp->b_io_remaining); |
| 1212 | nr_pages = BIO_MAX_SECTORS >> (PAGE_SHIFT - BBSHIFT); |
| 1213 | if (nr_pages > total_nr_pages) |
| 1214 | nr_pages = total_nr_pages; |
| 1215 | |
| 1216 | bio = bio_alloc(GFP_NOIO, nr_pages); |
| 1217 | bio->bi_bdev = bp->b_target->bt_bdev; |
| 1218 | bio->bi_sector = sector; |
| 1219 | bio->bi_end_io = xfs_buf_bio_end_io; |
| 1220 | bio->bi_private = bp; |
| 1221 | |
| 1222 | |
| 1223 | for (; size && nr_pages; nr_pages--, map_i++) { |
| 1224 | int rbytes, nbytes = PAGE_SIZE - offset; |
| 1225 | |
| 1226 | if (nbytes > size) |
| 1227 | nbytes = size; |
| 1228 | |
| 1229 | rbytes = bio_add_page(bio, bp->b_pages[map_i], nbytes, offset); |
| 1230 | if (rbytes < nbytes) |
| 1231 | break; |
| 1232 | |
| 1233 | offset = 0; |
| 1234 | sector += nbytes >> BBSHIFT; |
| 1235 | size -= nbytes; |
| 1236 | total_nr_pages--; |
| 1237 | } |
| 1238 | |
| 1239 | if (likely(bio->bi_size)) { |
| 1240 | if (xfs_buf_is_vmapped(bp)) { |
| 1241 | flush_kernel_vmap_range(bp->b_addr, |
| 1242 | xfs_buf_vmap_len(bp)); |
| 1243 | } |
| 1244 | submit_bio(rw, bio); |
| 1245 | if (size) |
| 1246 | goto next_chunk; |
| 1247 | } else { |
| 1248 | xfs_buf_ioerror(bp, EIO); |
| 1249 | bio_put(bio); |
| 1250 | } |
| 1251 | } |
| 1252 | |
| 1253 | int |
| 1254 | xfs_buf_iorequest( |
| 1255 | xfs_buf_t *bp) |
| 1256 | { |
| 1257 | trace_xfs_buf_iorequest(bp, _RET_IP_); |
| 1258 | |
| 1259 | ASSERT(!(bp->b_flags & XBF_DELWRI)); |
| 1260 | |
| 1261 | if (bp->b_flags & XBF_WRITE) |
| 1262 | xfs_buf_wait_unpin(bp); |
| 1263 | xfs_buf_hold(bp); |
| 1264 | |
| 1265 | /* Set the count to 1 initially, this will stop an I/O |
| 1266 | * completion callout which happens before we have started |
| 1267 | * all the I/O from calling xfs_buf_ioend too early. |
| 1268 | */ |
| 1269 | atomic_set(&bp->b_io_remaining, 1); |
| 1270 | _xfs_buf_ioapply(bp); |
| 1271 | _xfs_buf_ioend(bp, 0); |
| 1272 | |
| 1273 | xfs_buf_rele(bp); |
| 1274 | return 0; |
| 1275 | } |
| 1276 | |
| 1277 | /* |
| 1278 | * Waits for I/O to complete on the buffer supplied. |
| 1279 | * It returns immediately if no I/O is pending. |
| 1280 | * It returns the I/O error code, if any, or 0 if there was no error. |
| 1281 | */ |
| 1282 | int |
| 1283 | xfs_buf_iowait( |
| 1284 | xfs_buf_t *bp) |
| 1285 | { |
| 1286 | trace_xfs_buf_iowait(bp, _RET_IP_); |
| 1287 | |
| 1288 | wait_for_completion(&bp->b_iowait); |
| 1289 | |
| 1290 | trace_xfs_buf_iowait_done(bp, _RET_IP_); |
| 1291 | return bp->b_error; |
| 1292 | } |
| 1293 | |
| 1294 | xfs_caddr_t |
| 1295 | xfs_buf_offset( |
| 1296 | xfs_buf_t *bp, |
| 1297 | size_t offset) |
| 1298 | { |
| 1299 | struct page *page; |
| 1300 | |
| 1301 | if (bp->b_flags & XBF_MAPPED) |
| 1302 | return bp->b_addr + offset; |
| 1303 | |
| 1304 | offset += bp->b_offset; |
| 1305 | page = bp->b_pages[offset >> PAGE_SHIFT]; |
| 1306 | return (xfs_caddr_t)page_address(page) + (offset & (PAGE_SIZE-1)); |
| 1307 | } |
| 1308 | |
| 1309 | /* |
| 1310 | * Move data into or out of a buffer. |
| 1311 | */ |
| 1312 | void |
| 1313 | xfs_buf_iomove( |
| 1314 | xfs_buf_t *bp, /* buffer to process */ |
| 1315 | size_t boff, /* starting buffer offset */ |
| 1316 | size_t bsize, /* length to copy */ |
| 1317 | void *data, /* data address */ |
| 1318 | xfs_buf_rw_t mode) /* read/write/zero flag */ |
| 1319 | { |
| 1320 | size_t bend, cpoff, csize; |
| 1321 | struct page *page; |
| 1322 | |
| 1323 | bend = boff + bsize; |
| 1324 | while (boff < bend) { |
| 1325 | page = bp->b_pages[xfs_buf_btoct(boff + bp->b_offset)]; |
| 1326 | cpoff = xfs_buf_poff(boff + bp->b_offset); |
| 1327 | csize = min_t(size_t, |
| 1328 | PAGE_SIZE-cpoff, bp->b_count_desired-boff); |
| 1329 | |
| 1330 | ASSERT(((csize + cpoff) <= PAGE_SIZE)); |
| 1331 | |
| 1332 | switch (mode) { |
| 1333 | case XBRW_ZERO: |
| 1334 | memset(page_address(page) + cpoff, 0, csize); |
| 1335 | break; |
| 1336 | case XBRW_READ: |
| 1337 | memcpy(data, page_address(page) + cpoff, csize); |
| 1338 | break; |
| 1339 | case XBRW_WRITE: |
| 1340 | memcpy(page_address(page) + cpoff, data, csize); |
| 1341 | } |
| 1342 | |
| 1343 | boff += csize; |
| 1344 | data += csize; |
| 1345 | } |
| 1346 | } |
| 1347 | |
| 1348 | /* |
| 1349 | * Handling of buffer targets (buftargs). |
| 1350 | */ |
| 1351 | |
| 1352 | /* |
| 1353 | * Wait for any bufs with callbacks that have been submitted but have not yet |
| 1354 | * returned. These buffers will have an elevated hold count, so wait on those |
| 1355 | * while freeing all the buffers only held by the LRU. |
| 1356 | */ |
| 1357 | void |
| 1358 | xfs_wait_buftarg( |
| 1359 | struct xfs_buftarg *btp) |
| 1360 | { |
| 1361 | struct xfs_buf *bp; |
| 1362 | |
| 1363 | restart: |
| 1364 | spin_lock(&btp->bt_lru_lock); |
| 1365 | while (!list_empty(&btp->bt_lru)) { |
| 1366 | bp = list_first_entry(&btp->bt_lru, struct xfs_buf, b_lru); |
| 1367 | if (atomic_read(&bp->b_hold) > 1) { |
| 1368 | spin_unlock(&btp->bt_lru_lock); |
| 1369 | delay(100); |
| 1370 | goto restart; |
| 1371 | } |
| 1372 | /* |
| 1373 | * clear the LRU reference count so the bufer doesn't get |
| 1374 | * ignored in xfs_buf_rele(). |
| 1375 | */ |
| 1376 | atomic_set(&bp->b_lru_ref, 0); |
| 1377 | spin_unlock(&btp->bt_lru_lock); |
| 1378 | xfs_buf_rele(bp); |
| 1379 | spin_lock(&btp->bt_lru_lock); |
| 1380 | } |
| 1381 | spin_unlock(&btp->bt_lru_lock); |
| 1382 | } |
| 1383 | |
| 1384 | int |
| 1385 | xfs_buftarg_shrink( |
| 1386 | struct shrinker *shrink, |
| 1387 | struct shrink_control *sc) |
| 1388 | { |
| 1389 | struct xfs_buftarg *btp = container_of(shrink, |
| 1390 | struct xfs_buftarg, bt_shrinker); |
| 1391 | struct xfs_buf *bp; |
| 1392 | int nr_to_scan = sc->nr_to_scan; |
| 1393 | LIST_HEAD(dispose); |
| 1394 | |
| 1395 | if (!nr_to_scan) |
| 1396 | return btp->bt_lru_nr; |
| 1397 | |
| 1398 | spin_lock(&btp->bt_lru_lock); |
| 1399 | while (!list_empty(&btp->bt_lru)) { |
| 1400 | if (nr_to_scan-- <= 0) |
| 1401 | break; |
| 1402 | |
| 1403 | bp = list_first_entry(&btp->bt_lru, struct xfs_buf, b_lru); |
| 1404 | |
| 1405 | /* |
| 1406 | * Decrement the b_lru_ref count unless the value is already |
| 1407 | * zero. If the value is already zero, we need to reclaim the |
| 1408 | * buffer, otherwise it gets another trip through the LRU. |
| 1409 | */ |
| 1410 | if (!atomic_add_unless(&bp->b_lru_ref, -1, 0)) { |
| 1411 | list_move_tail(&bp->b_lru, &btp->bt_lru); |
| 1412 | continue; |
| 1413 | } |
| 1414 | |
| 1415 | /* |
| 1416 | * remove the buffer from the LRU now to avoid needing another |
| 1417 | * lock round trip inside xfs_buf_rele(). |
| 1418 | */ |
| 1419 | list_move(&bp->b_lru, &dispose); |
| 1420 | btp->bt_lru_nr--; |
| 1421 | } |
| 1422 | spin_unlock(&btp->bt_lru_lock); |
| 1423 | |
| 1424 | while (!list_empty(&dispose)) { |
| 1425 | bp = list_first_entry(&dispose, struct xfs_buf, b_lru); |
| 1426 | list_del_init(&bp->b_lru); |
| 1427 | xfs_buf_rele(bp); |
| 1428 | } |
| 1429 | |
| 1430 | return btp->bt_lru_nr; |
| 1431 | } |
| 1432 | |
| 1433 | void |
| 1434 | xfs_free_buftarg( |
| 1435 | struct xfs_mount *mp, |
| 1436 | struct xfs_buftarg *btp) |
| 1437 | { |
| 1438 | unregister_shrinker(&btp->bt_shrinker); |
| 1439 | |
| 1440 | xfs_flush_buftarg(btp, 1); |
| 1441 | if (mp->m_flags & XFS_MOUNT_BARRIER) |
| 1442 | xfs_blkdev_issue_flush(btp); |
| 1443 | |
| 1444 | kthread_stop(btp->bt_task); |
| 1445 | kmem_free(btp); |
| 1446 | } |
| 1447 | |
| 1448 | STATIC int |
| 1449 | xfs_setsize_buftarg_flags( |
| 1450 | xfs_buftarg_t *btp, |
| 1451 | unsigned int blocksize, |
| 1452 | unsigned int sectorsize, |
| 1453 | int verbose) |
| 1454 | { |
| 1455 | btp->bt_bsize = blocksize; |
| 1456 | btp->bt_sshift = ffs(sectorsize) - 1; |
| 1457 | btp->bt_smask = sectorsize - 1; |
| 1458 | |
| 1459 | if (set_blocksize(btp->bt_bdev, sectorsize)) { |
| 1460 | xfs_warn(btp->bt_mount, |
| 1461 | "Cannot set_blocksize to %u on device %s\n", |
| 1462 | sectorsize, xfs_buf_target_name(btp)); |
| 1463 | return EINVAL; |
| 1464 | } |
| 1465 | |
| 1466 | return 0; |
| 1467 | } |
| 1468 | |
| 1469 | /* |
| 1470 | * When allocating the initial buffer target we have not yet |
| 1471 | * read in the superblock, so don't know what sized sectors |
| 1472 | * are being used is at this early stage. Play safe. |
| 1473 | */ |
| 1474 | STATIC int |
| 1475 | xfs_setsize_buftarg_early( |
| 1476 | xfs_buftarg_t *btp, |
| 1477 | struct block_device *bdev) |
| 1478 | { |
| 1479 | return xfs_setsize_buftarg_flags(btp, |
| 1480 | PAGE_SIZE, bdev_logical_block_size(bdev), 0); |
| 1481 | } |
| 1482 | |
| 1483 | int |
| 1484 | xfs_setsize_buftarg( |
| 1485 | xfs_buftarg_t *btp, |
| 1486 | unsigned int blocksize, |
| 1487 | unsigned int sectorsize) |
| 1488 | { |
| 1489 | return xfs_setsize_buftarg_flags(btp, blocksize, sectorsize, 1); |
| 1490 | } |
| 1491 | |
| 1492 | STATIC int |
| 1493 | xfs_alloc_delwri_queue( |
| 1494 | xfs_buftarg_t *btp, |
| 1495 | const char *fsname) |
| 1496 | { |
| 1497 | INIT_LIST_HEAD(&btp->bt_delwri_queue); |
| 1498 | spin_lock_init(&btp->bt_delwri_lock); |
| 1499 | btp->bt_flags = 0; |
| 1500 | btp->bt_task = kthread_run(xfsbufd, btp, "xfsbufd/%s", fsname); |
| 1501 | if (IS_ERR(btp->bt_task)) |
| 1502 | return PTR_ERR(btp->bt_task); |
| 1503 | return 0; |
| 1504 | } |
| 1505 | |
| 1506 | xfs_buftarg_t * |
| 1507 | xfs_alloc_buftarg( |
| 1508 | struct xfs_mount *mp, |
| 1509 | struct block_device *bdev, |
| 1510 | int external, |
| 1511 | const char *fsname) |
| 1512 | { |
| 1513 | xfs_buftarg_t *btp; |
| 1514 | |
| 1515 | btp = kmem_zalloc(sizeof(*btp), KM_SLEEP); |
| 1516 | |
| 1517 | btp->bt_mount = mp; |
| 1518 | btp->bt_dev = bdev->bd_dev; |
| 1519 | btp->bt_bdev = bdev; |
| 1520 | btp->bt_bdi = blk_get_backing_dev_info(bdev); |
| 1521 | if (!btp->bt_bdi) |
| 1522 | goto error; |
| 1523 | |
| 1524 | INIT_LIST_HEAD(&btp->bt_lru); |
| 1525 | spin_lock_init(&btp->bt_lru_lock); |
| 1526 | if (xfs_setsize_buftarg_early(btp, bdev)) |
| 1527 | goto error; |
| 1528 | if (xfs_alloc_delwri_queue(btp, fsname)) |
| 1529 | goto error; |
| 1530 | btp->bt_shrinker.shrink = xfs_buftarg_shrink; |
| 1531 | btp->bt_shrinker.seeks = DEFAULT_SEEKS; |
| 1532 | register_shrinker(&btp->bt_shrinker); |
| 1533 | return btp; |
| 1534 | |
| 1535 | error: |
| 1536 | kmem_free(btp); |
| 1537 | return NULL; |
| 1538 | } |
| 1539 | |
| 1540 | |
| 1541 | /* |
| 1542 | * Delayed write buffer handling |
| 1543 | */ |
| 1544 | void |
| 1545 | xfs_buf_delwri_queue( |
| 1546 | xfs_buf_t *bp) |
| 1547 | { |
| 1548 | struct xfs_buftarg *btp = bp->b_target; |
| 1549 | |
| 1550 | trace_xfs_buf_delwri_queue(bp, _RET_IP_); |
| 1551 | |
| 1552 | ASSERT(!(bp->b_flags & XBF_READ)); |
| 1553 | |
| 1554 | spin_lock(&btp->bt_delwri_lock); |
| 1555 | if (!list_empty(&bp->b_list)) { |
| 1556 | /* if already in the queue, move it to the tail */ |
| 1557 | ASSERT(bp->b_flags & _XBF_DELWRI_Q); |
| 1558 | list_move_tail(&bp->b_list, &btp->bt_delwri_queue); |
| 1559 | } else { |
| 1560 | /* start xfsbufd as it is about to have something to do */ |
| 1561 | if (list_empty(&btp->bt_delwri_queue)) |
| 1562 | wake_up_process(bp->b_target->bt_task); |
| 1563 | |
| 1564 | atomic_inc(&bp->b_hold); |
| 1565 | bp->b_flags |= XBF_DELWRI | _XBF_DELWRI_Q | XBF_ASYNC; |
| 1566 | list_add_tail(&bp->b_list, &btp->bt_delwri_queue); |
| 1567 | } |
| 1568 | bp->b_queuetime = jiffies; |
| 1569 | spin_unlock(&btp->bt_delwri_lock); |
| 1570 | } |
| 1571 | |
| 1572 | void |
| 1573 | xfs_buf_delwri_dequeue( |
| 1574 | xfs_buf_t *bp) |
| 1575 | { |
| 1576 | int dequeued = 0; |
| 1577 | |
| 1578 | spin_lock(&bp->b_target->bt_delwri_lock); |
| 1579 | if ((bp->b_flags & XBF_DELWRI) && !list_empty(&bp->b_list)) { |
| 1580 | ASSERT(bp->b_flags & _XBF_DELWRI_Q); |
| 1581 | list_del_init(&bp->b_list); |
| 1582 | dequeued = 1; |
| 1583 | } |
| 1584 | bp->b_flags &= ~(XBF_DELWRI|_XBF_DELWRI_Q); |
| 1585 | spin_unlock(&bp->b_target->bt_delwri_lock); |
| 1586 | |
| 1587 | if (dequeued) |
| 1588 | xfs_buf_rele(bp); |
| 1589 | |
| 1590 | trace_xfs_buf_delwri_dequeue(bp, _RET_IP_); |
| 1591 | } |
| 1592 | |
| 1593 | /* |
| 1594 | * If a delwri buffer needs to be pushed before it has aged out, then promote |
| 1595 | * it to the head of the delwri queue so that it will be flushed on the next |
| 1596 | * xfsbufd run. We do this by resetting the queuetime of the buffer to be older |
| 1597 | * than the age currently needed to flush the buffer. Hence the next time the |
| 1598 | * xfsbufd sees it is guaranteed to be considered old enough to flush. |
| 1599 | */ |
| 1600 | void |
| 1601 | xfs_buf_delwri_promote( |
| 1602 | struct xfs_buf *bp) |
| 1603 | { |
| 1604 | struct xfs_buftarg *btp = bp->b_target; |
| 1605 | long age = xfs_buf_age_centisecs * msecs_to_jiffies(10) + 1; |
| 1606 | |
| 1607 | ASSERT(bp->b_flags & XBF_DELWRI); |
| 1608 | ASSERT(bp->b_flags & _XBF_DELWRI_Q); |
| 1609 | |
| 1610 | /* |
| 1611 | * Check the buffer age before locking the delayed write queue as we |
| 1612 | * don't need to promote buffers that are already past the flush age. |
| 1613 | */ |
| 1614 | if (bp->b_queuetime < jiffies - age) |
| 1615 | return; |
| 1616 | bp->b_queuetime = jiffies - age; |
| 1617 | spin_lock(&btp->bt_delwri_lock); |
| 1618 | list_move(&bp->b_list, &btp->bt_delwri_queue); |
| 1619 | spin_unlock(&btp->bt_delwri_lock); |
| 1620 | } |
| 1621 | |
| 1622 | STATIC void |
| 1623 | xfs_buf_runall_queues( |
| 1624 | struct workqueue_struct *queue) |
| 1625 | { |
| 1626 | flush_workqueue(queue); |
| 1627 | } |
| 1628 | |
| 1629 | /* |
| 1630 | * Move as many buffers as specified to the supplied list |
| 1631 | * idicating if we skipped any buffers to prevent deadlocks. |
| 1632 | */ |
| 1633 | STATIC int |
| 1634 | xfs_buf_delwri_split( |
| 1635 | xfs_buftarg_t *target, |
| 1636 | struct list_head *list, |
| 1637 | unsigned long age) |
| 1638 | { |
| 1639 | xfs_buf_t *bp, *n; |
| 1640 | int skipped = 0; |
| 1641 | int force; |
| 1642 | |
| 1643 | force = test_and_clear_bit(XBT_FORCE_FLUSH, &target->bt_flags); |
| 1644 | INIT_LIST_HEAD(list); |
| 1645 | spin_lock(&target->bt_delwri_lock); |
| 1646 | list_for_each_entry_safe(bp, n, &target->bt_delwri_queue, b_list) { |
| 1647 | ASSERT(bp->b_flags & XBF_DELWRI); |
| 1648 | |
| 1649 | if (!xfs_buf_ispinned(bp) && xfs_buf_trylock(bp)) { |
| 1650 | if (!force && |
| 1651 | time_before(jiffies, bp->b_queuetime + age)) { |
| 1652 | xfs_buf_unlock(bp); |
| 1653 | break; |
| 1654 | } |
| 1655 | |
| 1656 | bp->b_flags &= ~(XBF_DELWRI | _XBF_DELWRI_Q); |
| 1657 | bp->b_flags |= XBF_WRITE; |
| 1658 | list_move_tail(&bp->b_list, list); |
| 1659 | trace_xfs_buf_delwri_split(bp, _RET_IP_); |
| 1660 | } else |
| 1661 | skipped++; |
| 1662 | } |
| 1663 | |
| 1664 | spin_unlock(&target->bt_delwri_lock); |
| 1665 | return skipped; |
| 1666 | } |
| 1667 | |
| 1668 | /* |
| 1669 | * Compare function is more complex than it needs to be because |
| 1670 | * the return value is only 32 bits and we are doing comparisons |
| 1671 | * on 64 bit values |
| 1672 | */ |
| 1673 | static int |
| 1674 | xfs_buf_cmp( |
| 1675 | void *priv, |
| 1676 | struct list_head *a, |
| 1677 | struct list_head *b) |
| 1678 | { |
| 1679 | struct xfs_buf *ap = container_of(a, struct xfs_buf, b_list); |
| 1680 | struct xfs_buf *bp = container_of(b, struct xfs_buf, b_list); |
| 1681 | xfs_daddr_t diff; |
| 1682 | |
| 1683 | diff = ap->b_bn - bp->b_bn; |
| 1684 | if (diff < 0) |
| 1685 | return -1; |
| 1686 | if (diff > 0) |
| 1687 | return 1; |
| 1688 | return 0; |
| 1689 | } |
| 1690 | |
| 1691 | STATIC int |
| 1692 | xfsbufd( |
| 1693 | void *data) |
| 1694 | { |
| 1695 | xfs_buftarg_t *target = (xfs_buftarg_t *)data; |
| 1696 | |
| 1697 | current->flags |= PF_MEMALLOC; |
| 1698 | |
| 1699 | set_freezable(); |
| 1700 | |
| 1701 | do { |
| 1702 | long age = xfs_buf_age_centisecs * msecs_to_jiffies(10); |
| 1703 | long tout = xfs_buf_timer_centisecs * msecs_to_jiffies(10); |
| 1704 | struct list_head tmp; |
| 1705 | struct blk_plug plug; |
| 1706 | |
| 1707 | if (unlikely(freezing(current))) { |
| 1708 | set_bit(XBT_FORCE_SLEEP, &target->bt_flags); |
| 1709 | refrigerator(); |
| 1710 | } else { |
| 1711 | clear_bit(XBT_FORCE_SLEEP, &target->bt_flags); |
| 1712 | } |
| 1713 | |
| 1714 | /* sleep for a long time if there is nothing to do. */ |
| 1715 | if (list_empty(&target->bt_delwri_queue)) |
| 1716 | tout = MAX_SCHEDULE_TIMEOUT; |
| 1717 | schedule_timeout_interruptible(tout); |
| 1718 | |
| 1719 | xfs_buf_delwri_split(target, &tmp, age); |
| 1720 | list_sort(NULL, &tmp, xfs_buf_cmp); |
| 1721 | |
| 1722 | blk_start_plug(&plug); |
| 1723 | while (!list_empty(&tmp)) { |
| 1724 | struct xfs_buf *bp; |
| 1725 | bp = list_first_entry(&tmp, struct xfs_buf, b_list); |
| 1726 | list_del_init(&bp->b_list); |
| 1727 | xfs_bdstrat_cb(bp); |
| 1728 | } |
| 1729 | blk_finish_plug(&plug); |
| 1730 | } while (!kthread_should_stop()); |
| 1731 | |
| 1732 | return 0; |
| 1733 | } |
| 1734 | |
| 1735 | /* |
| 1736 | * Go through all incore buffers, and release buffers if they belong to |
| 1737 | * the given device. This is used in filesystem error handling to |
| 1738 | * preserve the consistency of its metadata. |
| 1739 | */ |
| 1740 | int |
| 1741 | xfs_flush_buftarg( |
| 1742 | xfs_buftarg_t *target, |
| 1743 | int wait) |
| 1744 | { |
| 1745 | xfs_buf_t *bp; |
| 1746 | int pincount = 0; |
| 1747 | LIST_HEAD(tmp_list); |
| 1748 | LIST_HEAD(wait_list); |
| 1749 | struct blk_plug plug; |
| 1750 | |
| 1751 | xfs_buf_runall_queues(xfsconvertd_workqueue); |
| 1752 | xfs_buf_runall_queues(xfsdatad_workqueue); |
| 1753 | xfs_buf_runall_queues(xfslogd_workqueue); |
| 1754 | |
| 1755 | set_bit(XBT_FORCE_FLUSH, &target->bt_flags); |
| 1756 | pincount = xfs_buf_delwri_split(target, &tmp_list, 0); |
| 1757 | |
| 1758 | /* |
| 1759 | * Dropped the delayed write list lock, now walk the temporary list. |
| 1760 | * All I/O is issued async and then if we need to wait for completion |
| 1761 | * we do that after issuing all the IO. |
| 1762 | */ |
| 1763 | list_sort(NULL, &tmp_list, xfs_buf_cmp); |
| 1764 | |
| 1765 | blk_start_plug(&plug); |
| 1766 | while (!list_empty(&tmp_list)) { |
| 1767 | bp = list_first_entry(&tmp_list, struct xfs_buf, b_list); |
| 1768 | ASSERT(target == bp->b_target); |
| 1769 | list_del_init(&bp->b_list); |
| 1770 | if (wait) { |
| 1771 | bp->b_flags &= ~XBF_ASYNC; |
| 1772 | list_add(&bp->b_list, &wait_list); |
| 1773 | } |
| 1774 | xfs_bdstrat_cb(bp); |
| 1775 | } |
| 1776 | blk_finish_plug(&plug); |
| 1777 | |
| 1778 | if (wait) { |
| 1779 | /* Wait for IO to complete. */ |
| 1780 | while (!list_empty(&wait_list)) { |
| 1781 | bp = list_first_entry(&wait_list, struct xfs_buf, b_list); |
| 1782 | |
| 1783 | list_del_init(&bp->b_list); |
| 1784 | xfs_buf_iowait(bp); |
| 1785 | xfs_buf_relse(bp); |
| 1786 | } |
| 1787 | } |
| 1788 | |
| 1789 | return pincount; |
| 1790 | } |
| 1791 | |
| 1792 | int __init |
| 1793 | xfs_buf_init(void) |
| 1794 | { |
| 1795 | xfs_buf_zone = kmem_zone_init_flags(sizeof(xfs_buf_t), "xfs_buf", |
| 1796 | KM_ZONE_HWALIGN, NULL); |
| 1797 | if (!xfs_buf_zone) |
| 1798 | goto out; |
| 1799 | |
| 1800 | xfslogd_workqueue = alloc_workqueue("xfslogd", |
| 1801 | WQ_MEM_RECLAIM | WQ_HIGHPRI, 1); |
| 1802 | if (!xfslogd_workqueue) |
| 1803 | goto out_free_buf_zone; |
| 1804 | |
| 1805 | xfsdatad_workqueue = alloc_workqueue("xfsdatad", WQ_MEM_RECLAIM, 1); |
| 1806 | if (!xfsdatad_workqueue) |
| 1807 | goto out_destroy_xfslogd_workqueue; |
| 1808 | |
| 1809 | xfsconvertd_workqueue = alloc_workqueue("xfsconvertd", |
| 1810 | WQ_MEM_RECLAIM, 1); |
| 1811 | if (!xfsconvertd_workqueue) |
| 1812 | goto out_destroy_xfsdatad_workqueue; |
| 1813 | |
| 1814 | return 0; |
| 1815 | |
| 1816 | out_destroy_xfsdatad_workqueue: |
| 1817 | destroy_workqueue(xfsdatad_workqueue); |
| 1818 | out_destroy_xfslogd_workqueue: |
| 1819 | destroy_workqueue(xfslogd_workqueue); |
| 1820 | out_free_buf_zone: |
| 1821 | kmem_zone_destroy(xfs_buf_zone); |
| 1822 | out: |
| 1823 | return -ENOMEM; |
| 1824 | } |
| 1825 | |
| 1826 | void |
| 1827 | xfs_buf_terminate(void) |
| 1828 | { |
| 1829 | destroy_workqueue(xfsconvertd_workqueue); |
| 1830 | destroy_workqueue(xfsdatad_workqueue); |
| 1831 | destroy_workqueue(xfslogd_workqueue); |
| 1832 | kmem_zone_destroy(xfs_buf_zone); |
| 1833 | } |