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Commit | Line | Data |
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1da177e4 | 1 | /* |
f07c2250 | 2 | * Copyright (c) 2000-2006 Silicon Graphics, Inc. |
7b718769 | 3 | * All Rights Reserved. |
1da177e4 | 4 | * |
7b718769 NS |
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 | |
1da177e4 LT |
7 | * published by the Free Software Foundation. |
8 | * | |
7b718769 NS |
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. | |
1da177e4 | 13 | * |
7b718769 NS |
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 | |
1da177e4 | 17 | */ |
93c189c1 | 18 | #include "xfs.h" |
1da177e4 LT |
19 | #include <linux/stddef.h> |
20 | #include <linux/errno.h> | |
5a0e3ad6 | 21 | #include <linux/gfp.h> |
1da177e4 LT |
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> | |
4df08c52 | 32 | #include <linux/kthread.h> |
b20a3503 | 33 | #include <linux/migrate.h> |
3fcfab16 | 34 | #include <linux/backing-dev.h> |
7dfb7103 | 35 | #include <linux/freezer.h> |
5b3cc15a | 36 | #include <linux/sched/mm.h> |
1da177e4 | 37 | |
4fb6e8ad | 38 | #include "xfs_format.h" |
239880ef | 39 | #include "xfs_log_format.h" |
7fd36c44 | 40 | #include "xfs_trans_resv.h" |
239880ef | 41 | #include "xfs_sb.h" |
b7963133 | 42 | #include "xfs_mount.h" |
0b1b213f | 43 | #include "xfs_trace.h" |
239880ef | 44 | #include "xfs_log.h" |
e9e899a2 | 45 | #include "xfs_errortag.h" |
7561d27e | 46 | #include "xfs_error.h" |
b7963133 | 47 | |
7989cb8e | 48 | static kmem_zone_t *xfs_buf_zone; |
23ea4032 | 49 | |
ce8e922c NS |
50 | #ifdef XFS_BUF_LOCK_TRACKING |
51 | # define XB_SET_OWNER(bp) ((bp)->b_last_holder = current->pid) | |
52 | # define XB_CLEAR_OWNER(bp) ((bp)->b_last_holder = -1) | |
53 | # define XB_GET_OWNER(bp) ((bp)->b_last_holder) | |
1da177e4 | 54 | #else |
ce8e922c NS |
55 | # define XB_SET_OWNER(bp) do { } while (0) |
56 | # define XB_CLEAR_OWNER(bp) do { } while (0) | |
57 | # define XB_GET_OWNER(bp) do { } while (0) | |
1da177e4 LT |
58 | #endif |
59 | ||
ce8e922c | 60 | #define xb_to_gfp(flags) \ |
aa5c158e | 61 | ((((flags) & XBF_READ_AHEAD) ? __GFP_NORETRY : GFP_NOFS) | __GFP_NOWARN) |
1da177e4 | 62 | |
1da177e4 | 63 | |
73c77e2c JB |
64 | static inline int |
65 | xfs_buf_is_vmapped( | |
66 | struct xfs_buf *bp) | |
67 | { | |
68 | /* | |
69 | * Return true if the buffer is vmapped. | |
70 | * | |
611c9946 DC |
71 | * b_addr is null if the buffer is not mapped, but the code is clever |
72 | * enough to know it doesn't have to map a single page, so the check has | |
73 | * to be both for b_addr and bp->b_page_count > 1. | |
73c77e2c | 74 | */ |
611c9946 | 75 | return bp->b_addr && bp->b_page_count > 1; |
73c77e2c JB |
76 | } |
77 | ||
78 | static inline int | |
79 | xfs_buf_vmap_len( | |
80 | struct xfs_buf *bp) | |
81 | { | |
82 | return (bp->b_page_count * PAGE_SIZE) - bp->b_offset; | |
83 | } | |
84 | ||
9c7504aa BF |
85 | /* |
86 | * Bump the I/O in flight count on the buftarg if we haven't yet done so for | |
87 | * this buffer. The count is incremented once per buffer (per hold cycle) | |
88 | * because the corresponding decrement is deferred to buffer release. Buffers | |
89 | * can undergo I/O multiple times in a hold-release cycle and per buffer I/O | |
90 | * tracking adds unnecessary overhead. This is used for sychronization purposes | |
91 | * with unmount (see xfs_wait_buftarg()), so all we really need is a count of | |
92 | * in-flight buffers. | |
93 | * | |
94 | * Buffers that are never released (e.g., superblock, iclog buffers) must set | |
95 | * the XBF_NO_IOACCT flag before I/O submission. Otherwise, the buftarg count | |
96 | * never reaches zero and unmount hangs indefinitely. | |
97 | */ | |
98 | static inline void | |
99 | xfs_buf_ioacct_inc( | |
100 | struct xfs_buf *bp) | |
101 | { | |
63db7c81 | 102 | if (bp->b_flags & XBF_NO_IOACCT) |
9c7504aa BF |
103 | return; |
104 | ||
105 | ASSERT(bp->b_flags & XBF_ASYNC); | |
63db7c81 BF |
106 | spin_lock(&bp->b_lock); |
107 | if (!(bp->b_state & XFS_BSTATE_IN_FLIGHT)) { | |
108 | bp->b_state |= XFS_BSTATE_IN_FLIGHT; | |
109 | percpu_counter_inc(&bp->b_target->bt_io_count); | |
110 | } | |
111 | spin_unlock(&bp->b_lock); | |
9c7504aa BF |
112 | } |
113 | ||
114 | /* | |
115 | * Clear the in-flight state on a buffer about to be released to the LRU or | |
116 | * freed and unaccount from the buftarg. | |
117 | */ | |
118 | static inline void | |
63db7c81 | 119 | __xfs_buf_ioacct_dec( |
9c7504aa BF |
120 | struct xfs_buf *bp) |
121 | { | |
95989c46 | 122 | lockdep_assert_held(&bp->b_lock); |
9c7504aa | 123 | |
63db7c81 BF |
124 | if (bp->b_state & XFS_BSTATE_IN_FLIGHT) { |
125 | bp->b_state &= ~XFS_BSTATE_IN_FLIGHT; | |
126 | percpu_counter_dec(&bp->b_target->bt_io_count); | |
127 | } | |
128 | } | |
129 | ||
130 | static inline void | |
131 | xfs_buf_ioacct_dec( | |
132 | struct xfs_buf *bp) | |
133 | { | |
134 | spin_lock(&bp->b_lock); | |
135 | __xfs_buf_ioacct_dec(bp); | |
136 | spin_unlock(&bp->b_lock); | |
9c7504aa BF |
137 | } |
138 | ||
430cbeb8 DC |
139 | /* |
140 | * When we mark a buffer stale, we remove the buffer from the LRU and clear the | |
141 | * b_lru_ref count so that the buffer is freed immediately when the buffer | |
142 | * reference count falls to zero. If the buffer is already on the LRU, we need | |
143 | * to remove the reference that LRU holds on the buffer. | |
144 | * | |
145 | * This prevents build-up of stale buffers on the LRU. | |
146 | */ | |
147 | void | |
148 | xfs_buf_stale( | |
149 | struct xfs_buf *bp) | |
150 | { | |
43ff2122 CH |
151 | ASSERT(xfs_buf_islocked(bp)); |
152 | ||
430cbeb8 | 153 | bp->b_flags |= XBF_STALE; |
43ff2122 CH |
154 | |
155 | /* | |
156 | * Clear the delwri status so that a delwri queue walker will not | |
157 | * flush this buffer to disk now that it is stale. The delwri queue has | |
158 | * a reference to the buffer, so this is safe to do. | |
159 | */ | |
160 | bp->b_flags &= ~_XBF_DELWRI_Q; | |
161 | ||
9c7504aa BF |
162 | /* |
163 | * Once the buffer is marked stale and unlocked, a subsequent lookup | |
164 | * could reset b_flags. There is no guarantee that the buffer is | |
165 | * unaccounted (released to LRU) before that occurs. Drop in-flight | |
166 | * status now to preserve accounting consistency. | |
167 | */ | |
a4082357 | 168 | spin_lock(&bp->b_lock); |
63db7c81 BF |
169 | __xfs_buf_ioacct_dec(bp); |
170 | ||
a4082357 DC |
171 | atomic_set(&bp->b_lru_ref, 0); |
172 | if (!(bp->b_state & XFS_BSTATE_DISPOSE) && | |
e80dfa19 DC |
173 | (list_lru_del(&bp->b_target->bt_lru, &bp->b_lru))) |
174 | atomic_dec(&bp->b_hold); | |
175 | ||
430cbeb8 | 176 | ASSERT(atomic_read(&bp->b_hold) >= 1); |
a4082357 | 177 | spin_unlock(&bp->b_lock); |
430cbeb8 | 178 | } |
1da177e4 | 179 | |
3e85c868 DC |
180 | static int |
181 | xfs_buf_get_maps( | |
182 | struct xfs_buf *bp, | |
183 | int map_count) | |
184 | { | |
185 | ASSERT(bp->b_maps == NULL); | |
186 | bp->b_map_count = map_count; | |
187 | ||
188 | if (map_count == 1) { | |
f4b42421 | 189 | bp->b_maps = &bp->__b_map; |
3e85c868 DC |
190 | return 0; |
191 | } | |
192 | ||
193 | bp->b_maps = kmem_zalloc(map_count * sizeof(struct xfs_buf_map), | |
194 | KM_NOFS); | |
195 | if (!bp->b_maps) | |
2451337d | 196 | return -ENOMEM; |
3e85c868 DC |
197 | return 0; |
198 | } | |
199 | ||
200 | /* | |
201 | * Frees b_pages if it was allocated. | |
202 | */ | |
203 | static void | |
204 | xfs_buf_free_maps( | |
205 | struct xfs_buf *bp) | |
206 | { | |
f4b42421 | 207 | if (bp->b_maps != &bp->__b_map) { |
3e85c868 DC |
208 | kmem_free(bp->b_maps); |
209 | bp->b_maps = NULL; | |
210 | } | |
211 | } | |
212 | ||
4347b9d7 | 213 | struct xfs_buf * |
3e85c868 | 214 | _xfs_buf_alloc( |
4347b9d7 | 215 | struct xfs_buftarg *target, |
3e85c868 DC |
216 | struct xfs_buf_map *map, |
217 | int nmaps, | |
ce8e922c | 218 | xfs_buf_flags_t flags) |
1da177e4 | 219 | { |
4347b9d7 | 220 | struct xfs_buf *bp; |
3e85c868 DC |
221 | int error; |
222 | int i; | |
4347b9d7 | 223 | |
aa5c158e | 224 | bp = kmem_zone_zalloc(xfs_buf_zone, KM_NOFS); |
4347b9d7 CH |
225 | if (unlikely(!bp)) |
226 | return NULL; | |
227 | ||
1da177e4 | 228 | /* |
12bcb3f7 DC |
229 | * We don't want certain flags to appear in b_flags unless they are |
230 | * specifically set by later operations on the buffer. | |
1da177e4 | 231 | */ |
611c9946 | 232 | flags &= ~(XBF_UNMAPPED | XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD); |
ce8e922c | 233 | |
ce8e922c | 234 | atomic_set(&bp->b_hold, 1); |
430cbeb8 | 235 | atomic_set(&bp->b_lru_ref, 1); |
b4dd330b | 236 | init_completion(&bp->b_iowait); |
430cbeb8 | 237 | INIT_LIST_HEAD(&bp->b_lru); |
ce8e922c | 238 | INIT_LIST_HEAD(&bp->b_list); |
a731cd11 | 239 | sema_init(&bp->b_sema, 0); /* held, no waiters */ |
a4082357 | 240 | spin_lock_init(&bp->b_lock); |
ce8e922c NS |
241 | XB_SET_OWNER(bp); |
242 | bp->b_target = target; | |
3e85c868 | 243 | bp->b_flags = flags; |
de1cbee4 | 244 | |
1da177e4 | 245 | /* |
aa0e8833 DC |
246 | * Set length and io_length to the same value initially. |
247 | * I/O routines should use io_length, which will be the same in | |
1da177e4 LT |
248 | * most cases but may be reset (e.g. XFS recovery). |
249 | */ | |
3e85c868 DC |
250 | error = xfs_buf_get_maps(bp, nmaps); |
251 | if (error) { | |
252 | kmem_zone_free(xfs_buf_zone, bp); | |
253 | return NULL; | |
254 | } | |
255 | ||
256 | bp->b_bn = map[0].bm_bn; | |
257 | bp->b_length = 0; | |
258 | for (i = 0; i < nmaps; i++) { | |
259 | bp->b_maps[i].bm_bn = map[i].bm_bn; | |
260 | bp->b_maps[i].bm_len = map[i].bm_len; | |
261 | bp->b_length += map[i].bm_len; | |
262 | } | |
263 | bp->b_io_length = bp->b_length; | |
264 | ||
ce8e922c NS |
265 | atomic_set(&bp->b_pin_count, 0); |
266 | init_waitqueue_head(&bp->b_waiters); | |
267 | ||
ff6d6af2 | 268 | XFS_STATS_INC(target->bt_mount, xb_create); |
0b1b213f | 269 | trace_xfs_buf_init(bp, _RET_IP_); |
4347b9d7 CH |
270 | |
271 | return bp; | |
1da177e4 LT |
272 | } |
273 | ||
274 | /* | |
ce8e922c NS |
275 | * Allocate a page array capable of holding a specified number |
276 | * of pages, and point the page buf at it. | |
1da177e4 LT |
277 | */ |
278 | STATIC int | |
ce8e922c NS |
279 | _xfs_buf_get_pages( |
280 | xfs_buf_t *bp, | |
87937bf8 | 281 | int page_count) |
1da177e4 LT |
282 | { |
283 | /* Make sure that we have a page list */ | |
ce8e922c | 284 | if (bp->b_pages == NULL) { |
ce8e922c NS |
285 | bp->b_page_count = page_count; |
286 | if (page_count <= XB_PAGES) { | |
287 | bp->b_pages = bp->b_page_array; | |
1da177e4 | 288 | } else { |
ce8e922c | 289 | bp->b_pages = kmem_alloc(sizeof(struct page *) * |
aa5c158e | 290 | page_count, KM_NOFS); |
ce8e922c | 291 | if (bp->b_pages == NULL) |
1da177e4 LT |
292 | return -ENOMEM; |
293 | } | |
ce8e922c | 294 | memset(bp->b_pages, 0, sizeof(struct page *) * page_count); |
1da177e4 LT |
295 | } |
296 | return 0; | |
297 | } | |
298 | ||
299 | /* | |
ce8e922c | 300 | * Frees b_pages if it was allocated. |
1da177e4 LT |
301 | */ |
302 | STATIC void | |
ce8e922c | 303 | _xfs_buf_free_pages( |
1da177e4 LT |
304 | xfs_buf_t *bp) |
305 | { | |
ce8e922c | 306 | if (bp->b_pages != bp->b_page_array) { |
f0e2d93c | 307 | kmem_free(bp->b_pages); |
3fc98b1a | 308 | bp->b_pages = NULL; |
1da177e4 LT |
309 | } |
310 | } | |
311 | ||
312 | /* | |
313 | * Releases the specified buffer. | |
314 | * | |
315 | * The modification state of any associated pages is left unchanged. | |
b46fe825 | 316 | * The buffer must not be on any hash - use xfs_buf_rele instead for |
1da177e4 LT |
317 | * hashed and refcounted buffers |
318 | */ | |
319 | void | |
ce8e922c | 320 | xfs_buf_free( |
1da177e4 LT |
321 | xfs_buf_t *bp) |
322 | { | |
0b1b213f | 323 | trace_xfs_buf_free(bp, _RET_IP_); |
1da177e4 | 324 | |
430cbeb8 DC |
325 | ASSERT(list_empty(&bp->b_lru)); |
326 | ||
0e6e847f | 327 | if (bp->b_flags & _XBF_PAGES) { |
1da177e4 LT |
328 | uint i; |
329 | ||
73c77e2c | 330 | if (xfs_buf_is_vmapped(bp)) |
8a262e57 AE |
331 | vm_unmap_ram(bp->b_addr - bp->b_offset, |
332 | bp->b_page_count); | |
1da177e4 | 333 | |
948ecdb4 NS |
334 | for (i = 0; i < bp->b_page_count; i++) { |
335 | struct page *page = bp->b_pages[i]; | |
336 | ||
0e6e847f | 337 | __free_page(page); |
948ecdb4 | 338 | } |
0e6e847f DC |
339 | } else if (bp->b_flags & _XBF_KMEM) |
340 | kmem_free(bp->b_addr); | |
3fc98b1a | 341 | _xfs_buf_free_pages(bp); |
3e85c868 | 342 | xfs_buf_free_maps(bp); |
4347b9d7 | 343 | kmem_zone_free(xfs_buf_zone, bp); |
1da177e4 LT |
344 | } |
345 | ||
346 | /* | |
0e6e847f | 347 | * Allocates all the pages for buffer in question and builds it's page list. |
1da177e4 LT |
348 | */ |
349 | STATIC int | |
0e6e847f | 350 | xfs_buf_allocate_memory( |
1da177e4 LT |
351 | xfs_buf_t *bp, |
352 | uint flags) | |
353 | { | |
aa0e8833 | 354 | size_t size; |
1da177e4 | 355 | size_t nbytes, offset; |
ce8e922c | 356 | gfp_t gfp_mask = xb_to_gfp(flags); |
1da177e4 | 357 | unsigned short page_count, i; |
795cac72 | 358 | xfs_off_t start, end; |
1da177e4 LT |
359 | int error; |
360 | ||
0e6e847f DC |
361 | /* |
362 | * for buffers that are contained within a single page, just allocate | |
363 | * the memory from the heap - there's no need for the complexity of | |
364 | * page arrays to keep allocation down to order 0. | |
365 | */ | |
795cac72 DC |
366 | size = BBTOB(bp->b_length); |
367 | if (size < PAGE_SIZE) { | |
aa5c158e | 368 | bp->b_addr = kmem_alloc(size, KM_NOFS); |
0e6e847f DC |
369 | if (!bp->b_addr) { |
370 | /* low memory - use alloc_page loop instead */ | |
371 | goto use_alloc_page; | |
372 | } | |
373 | ||
795cac72 | 374 | if (((unsigned long)(bp->b_addr + size - 1) & PAGE_MASK) != |
0e6e847f DC |
375 | ((unsigned long)bp->b_addr & PAGE_MASK)) { |
376 | /* b_addr spans two pages - use alloc_page instead */ | |
377 | kmem_free(bp->b_addr); | |
378 | bp->b_addr = NULL; | |
379 | goto use_alloc_page; | |
380 | } | |
381 | bp->b_offset = offset_in_page(bp->b_addr); | |
382 | bp->b_pages = bp->b_page_array; | |
383 | bp->b_pages[0] = virt_to_page(bp->b_addr); | |
384 | bp->b_page_count = 1; | |
611c9946 | 385 | bp->b_flags |= _XBF_KMEM; |
0e6e847f DC |
386 | return 0; |
387 | } | |
388 | ||
389 | use_alloc_page: | |
f4b42421 MT |
390 | start = BBTOB(bp->b_maps[0].bm_bn) >> PAGE_SHIFT; |
391 | end = (BBTOB(bp->b_maps[0].bm_bn + bp->b_length) + PAGE_SIZE - 1) | |
cbb7baab | 392 | >> PAGE_SHIFT; |
795cac72 | 393 | page_count = end - start; |
87937bf8 | 394 | error = _xfs_buf_get_pages(bp, page_count); |
1da177e4 LT |
395 | if (unlikely(error)) |
396 | return error; | |
1da177e4 | 397 | |
ce8e922c | 398 | offset = bp->b_offset; |
0e6e847f | 399 | bp->b_flags |= _XBF_PAGES; |
1da177e4 | 400 | |
ce8e922c | 401 | for (i = 0; i < bp->b_page_count; i++) { |
1da177e4 LT |
402 | struct page *page; |
403 | uint retries = 0; | |
0e6e847f DC |
404 | retry: |
405 | page = alloc_page(gfp_mask); | |
1da177e4 | 406 | if (unlikely(page == NULL)) { |
ce8e922c NS |
407 | if (flags & XBF_READ_AHEAD) { |
408 | bp->b_page_count = i; | |
2451337d | 409 | error = -ENOMEM; |
0e6e847f | 410 | goto out_free_pages; |
1da177e4 LT |
411 | } |
412 | ||
413 | /* | |
414 | * This could deadlock. | |
415 | * | |
416 | * But until all the XFS lowlevel code is revamped to | |
417 | * handle buffer allocation failures we can't do much. | |
418 | */ | |
419 | if (!(++retries % 100)) | |
4f10700a | 420 | xfs_err(NULL, |
5bf97b1c TH |
421 | "%s(%u) possible memory allocation deadlock in %s (mode:0x%x)", |
422 | current->comm, current->pid, | |
34a622b2 | 423 | __func__, gfp_mask); |
1da177e4 | 424 | |
ff6d6af2 | 425 | XFS_STATS_INC(bp->b_target->bt_mount, xb_page_retries); |
8aa7e847 | 426 | congestion_wait(BLK_RW_ASYNC, HZ/50); |
1da177e4 LT |
427 | goto retry; |
428 | } | |
429 | ||
ff6d6af2 | 430 | XFS_STATS_INC(bp->b_target->bt_mount, xb_page_found); |
1da177e4 | 431 | |
0e6e847f | 432 | nbytes = min_t(size_t, size, PAGE_SIZE - offset); |
1da177e4 | 433 | size -= nbytes; |
ce8e922c | 434 | bp->b_pages[i] = page; |
1da177e4 LT |
435 | offset = 0; |
436 | } | |
0e6e847f | 437 | return 0; |
1da177e4 | 438 | |
0e6e847f DC |
439 | out_free_pages: |
440 | for (i = 0; i < bp->b_page_count; i++) | |
441 | __free_page(bp->b_pages[i]); | |
2aa6ba7b | 442 | bp->b_flags &= ~_XBF_PAGES; |
1da177e4 LT |
443 | return error; |
444 | } | |
445 | ||
446 | /* | |
25985edc | 447 | * Map buffer into kernel address-space if necessary. |
1da177e4 LT |
448 | */ |
449 | STATIC int | |
ce8e922c | 450 | _xfs_buf_map_pages( |
1da177e4 LT |
451 | xfs_buf_t *bp, |
452 | uint flags) | |
453 | { | |
0e6e847f | 454 | ASSERT(bp->b_flags & _XBF_PAGES); |
ce8e922c | 455 | if (bp->b_page_count == 1) { |
0e6e847f | 456 | /* A single page buffer is always mappable */ |
ce8e922c | 457 | bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset; |
611c9946 DC |
458 | } else if (flags & XBF_UNMAPPED) { |
459 | bp->b_addr = NULL; | |
460 | } else { | |
a19fb380 | 461 | int retried = 0; |
9ba1fb2c | 462 | unsigned nofs_flag; |
ae687e58 DC |
463 | |
464 | /* | |
465 | * vm_map_ram() will allocate auxillary structures (e.g. | |
466 | * pagetables) with GFP_KERNEL, yet we are likely to be under | |
467 | * GFP_NOFS context here. Hence we need to tell memory reclaim | |
9ba1fb2c | 468 | * that we are in such a context via PF_MEMALLOC_NOFS to prevent |
ae687e58 DC |
469 | * memory reclaim re-entering the filesystem here and |
470 | * potentially deadlocking. | |
471 | */ | |
9ba1fb2c | 472 | nofs_flag = memalloc_nofs_save(); |
a19fb380 DC |
473 | do { |
474 | bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count, | |
475 | -1, PAGE_KERNEL); | |
476 | if (bp->b_addr) | |
477 | break; | |
478 | vm_unmap_aliases(); | |
479 | } while (retried++ <= 1); | |
9ba1fb2c | 480 | memalloc_nofs_restore(nofs_flag); |
a19fb380 DC |
481 | |
482 | if (!bp->b_addr) | |
1da177e4 | 483 | return -ENOMEM; |
ce8e922c | 484 | bp->b_addr += bp->b_offset; |
1da177e4 LT |
485 | } |
486 | ||
487 | return 0; | |
488 | } | |
489 | ||
490 | /* | |
491 | * Finding and Reading Buffers | |
492 | */ | |
6031e73a LS |
493 | static int |
494 | _xfs_buf_obj_cmp( | |
495 | struct rhashtable_compare_arg *arg, | |
496 | const void *obj) | |
497 | { | |
498 | const struct xfs_buf_map *map = arg->key; | |
499 | const struct xfs_buf *bp = obj; | |
500 | ||
501 | /* | |
502 | * The key hashing in the lookup path depends on the key being the | |
503 | * first element of the compare_arg, make sure to assert this. | |
504 | */ | |
505 | BUILD_BUG_ON(offsetof(struct xfs_buf_map, bm_bn) != 0); | |
506 | ||
507 | if (bp->b_bn != map->bm_bn) | |
508 | return 1; | |
509 | ||
510 | if (unlikely(bp->b_length != map->bm_len)) { | |
511 | /* | |
512 | * found a block number match. If the range doesn't | |
513 | * match, the only way this is allowed is if the buffer | |
514 | * in the cache is stale and the transaction that made | |
515 | * it stale has not yet committed. i.e. we are | |
516 | * reallocating a busy extent. Skip this buffer and | |
517 | * continue searching for an exact match. | |
518 | */ | |
519 | ASSERT(bp->b_flags & XBF_STALE); | |
520 | return 1; | |
521 | } | |
522 | return 0; | |
523 | } | |
524 | ||
525 | static const struct rhashtable_params xfs_buf_hash_params = { | |
526 | .min_size = 32, /* empty AGs have minimal footprint */ | |
527 | .nelem_hint = 16, | |
528 | .key_len = sizeof(xfs_daddr_t), | |
529 | .key_offset = offsetof(struct xfs_buf, b_bn), | |
530 | .head_offset = offsetof(struct xfs_buf, b_rhash_head), | |
531 | .automatic_shrinking = true, | |
532 | .obj_cmpfn = _xfs_buf_obj_cmp, | |
533 | }; | |
534 | ||
535 | int | |
536 | xfs_buf_hash_init( | |
537 | struct xfs_perag *pag) | |
538 | { | |
539 | spin_lock_init(&pag->pag_buf_lock); | |
540 | return rhashtable_init(&pag->pag_buf_hash, &xfs_buf_hash_params); | |
541 | } | |
542 | ||
543 | void | |
544 | xfs_buf_hash_destroy( | |
545 | struct xfs_perag *pag) | |
546 | { | |
547 | rhashtable_destroy(&pag->pag_buf_hash); | |
548 | } | |
1da177e4 LT |
549 | |
550 | /* | |
ce8e922c | 551 | * Look up, and creates if absent, a lockable buffer for |
1da177e4 | 552 | * a given range of an inode. The buffer is returned |
eabbaf11 | 553 | * locked. No I/O is implied by this call. |
1da177e4 LT |
554 | */ |
555 | xfs_buf_t * | |
ce8e922c | 556 | _xfs_buf_find( |
e70b73f8 | 557 | struct xfs_buftarg *btp, |
3e85c868 DC |
558 | struct xfs_buf_map *map, |
559 | int nmaps, | |
ce8e922c NS |
560 | xfs_buf_flags_t flags, |
561 | xfs_buf_t *new_bp) | |
1da177e4 | 562 | { |
74f75a0c | 563 | struct xfs_perag *pag; |
74f75a0c | 564 | xfs_buf_t *bp; |
6031e73a | 565 | struct xfs_buf_map cmap = { .bm_bn = map[0].bm_bn }; |
10616b80 | 566 | xfs_daddr_t eofs; |
3e85c868 | 567 | int i; |
1da177e4 | 568 | |
3e85c868 | 569 | for (i = 0; i < nmaps; i++) |
6031e73a | 570 | cmap.bm_len += map[i].bm_len; |
1da177e4 LT |
571 | |
572 | /* Check for IOs smaller than the sector size / not sector aligned */ | |
6031e73a LS |
573 | ASSERT(!(BBTOB(cmap.bm_len) < btp->bt_meta_sectorsize)); |
574 | ASSERT(!(BBTOB(cmap.bm_bn) & (xfs_off_t)btp->bt_meta_sectormask)); | |
1da177e4 | 575 | |
10616b80 DC |
576 | /* |
577 | * Corrupted block numbers can get through to here, unfortunately, so we | |
578 | * have to check that the buffer falls within the filesystem bounds. | |
579 | */ | |
580 | eofs = XFS_FSB_TO_BB(btp->bt_mount, btp->bt_mount->m_sb.sb_dblocks); | |
6031e73a | 581 | if (cmap.bm_bn < 0 || cmap.bm_bn >= eofs) { |
10616b80 | 582 | /* |
2451337d | 583 | * XXX (dgc): we should really be returning -EFSCORRUPTED here, |
10616b80 DC |
584 | * but none of the higher level infrastructure supports |
585 | * returning a specific error on buffer lookup failures. | |
586 | */ | |
587 | xfs_alert(btp->bt_mount, | |
588 | "%s: Block out of range: block 0x%llx, EOFS 0x%llx ", | |
6031e73a | 589 | __func__, cmap.bm_bn, eofs); |
7bc0dc27 | 590 | WARN_ON(1); |
10616b80 DC |
591 | return NULL; |
592 | } | |
593 | ||
74f75a0c | 594 | pag = xfs_perag_get(btp->bt_mount, |
6031e73a | 595 | xfs_daddr_to_agno(btp->bt_mount, cmap.bm_bn)); |
74f75a0c | 596 | |
74f75a0c | 597 | spin_lock(&pag->pag_buf_lock); |
6031e73a LS |
598 | bp = rhashtable_lookup_fast(&pag->pag_buf_hash, &cmap, |
599 | xfs_buf_hash_params); | |
600 | if (bp) { | |
601 | atomic_inc(&bp->b_hold); | |
602 | goto found; | |
1da177e4 LT |
603 | } |
604 | ||
605 | /* No match found */ | |
ce8e922c | 606 | if (new_bp) { |
74f75a0c DC |
607 | /* the buffer keeps the perag reference until it is freed */ |
608 | new_bp->b_pag = pag; | |
6031e73a LS |
609 | rhashtable_insert_fast(&pag->pag_buf_hash, |
610 | &new_bp->b_rhash_head, | |
611 | xfs_buf_hash_params); | |
74f75a0c | 612 | spin_unlock(&pag->pag_buf_lock); |
1da177e4 | 613 | } else { |
ff6d6af2 | 614 | XFS_STATS_INC(btp->bt_mount, xb_miss_locked); |
74f75a0c DC |
615 | spin_unlock(&pag->pag_buf_lock); |
616 | xfs_perag_put(pag); | |
1da177e4 | 617 | } |
ce8e922c | 618 | return new_bp; |
1da177e4 LT |
619 | |
620 | found: | |
74f75a0c DC |
621 | spin_unlock(&pag->pag_buf_lock); |
622 | xfs_perag_put(pag); | |
1da177e4 | 623 | |
0c842ad4 CH |
624 | if (!xfs_buf_trylock(bp)) { |
625 | if (flags & XBF_TRYLOCK) { | |
ce8e922c | 626 | xfs_buf_rele(bp); |
ff6d6af2 | 627 | XFS_STATS_INC(btp->bt_mount, xb_busy_locked); |
ce8e922c | 628 | return NULL; |
1da177e4 | 629 | } |
0c842ad4 | 630 | xfs_buf_lock(bp); |
ff6d6af2 | 631 | XFS_STATS_INC(btp->bt_mount, xb_get_locked_waited); |
1da177e4 LT |
632 | } |
633 | ||
0e6e847f DC |
634 | /* |
635 | * if the buffer is stale, clear all the external state associated with | |
636 | * it. We need to keep flags such as how we allocated the buffer memory | |
637 | * intact here. | |
638 | */ | |
ce8e922c NS |
639 | if (bp->b_flags & XBF_STALE) { |
640 | ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0); | |
cfb02852 | 641 | ASSERT(bp->b_iodone == NULL); |
611c9946 | 642 | bp->b_flags &= _XBF_KMEM | _XBF_PAGES; |
1813dd64 | 643 | bp->b_ops = NULL; |
2f926587 | 644 | } |
0b1b213f CH |
645 | |
646 | trace_xfs_buf_find(bp, flags, _RET_IP_); | |
ff6d6af2 | 647 | XFS_STATS_INC(btp->bt_mount, xb_get_locked); |
ce8e922c | 648 | return bp; |
1da177e4 LT |
649 | } |
650 | ||
651 | /* | |
3815832a DC |
652 | * Assembles a buffer covering the specified range. The code is optimised for |
653 | * cache hits, as metadata intensive workloads will see 3 orders of magnitude | |
654 | * more hits than misses. | |
1da177e4 | 655 | */ |
3815832a | 656 | struct xfs_buf * |
6dde2707 DC |
657 | xfs_buf_get_map( |
658 | struct xfs_buftarg *target, | |
659 | struct xfs_buf_map *map, | |
660 | int nmaps, | |
ce8e922c | 661 | xfs_buf_flags_t flags) |
1da177e4 | 662 | { |
3815832a DC |
663 | struct xfs_buf *bp; |
664 | struct xfs_buf *new_bp; | |
0e6e847f | 665 | int error = 0; |
1da177e4 | 666 | |
6dde2707 | 667 | bp = _xfs_buf_find(target, map, nmaps, flags, NULL); |
3815832a DC |
668 | if (likely(bp)) |
669 | goto found; | |
670 | ||
6dde2707 | 671 | new_bp = _xfs_buf_alloc(target, map, nmaps, flags); |
ce8e922c | 672 | if (unlikely(!new_bp)) |
1da177e4 LT |
673 | return NULL; |
674 | ||
fe2429b0 DC |
675 | error = xfs_buf_allocate_memory(new_bp, flags); |
676 | if (error) { | |
3e85c868 | 677 | xfs_buf_free(new_bp); |
fe2429b0 DC |
678 | return NULL; |
679 | } | |
680 | ||
6dde2707 | 681 | bp = _xfs_buf_find(target, map, nmaps, flags, new_bp); |
3815832a | 682 | if (!bp) { |
fe2429b0 | 683 | xfs_buf_free(new_bp); |
3815832a DC |
684 | return NULL; |
685 | } | |
686 | ||
fe2429b0 DC |
687 | if (bp != new_bp) |
688 | xfs_buf_free(new_bp); | |
1da177e4 | 689 | |
3815832a | 690 | found: |
611c9946 | 691 | if (!bp->b_addr) { |
ce8e922c | 692 | error = _xfs_buf_map_pages(bp, flags); |
1da177e4 | 693 | if (unlikely(error)) { |
4f10700a | 694 | xfs_warn(target->bt_mount, |
08e96e1a | 695 | "%s: failed to map pagesn", __func__); |
a8acad70 DC |
696 | xfs_buf_relse(bp); |
697 | return NULL; | |
1da177e4 LT |
698 | } |
699 | } | |
700 | ||
b79f4a1c DC |
701 | /* |
702 | * Clear b_error if this is a lookup from a caller that doesn't expect | |
703 | * valid data to be found in the buffer. | |
704 | */ | |
705 | if (!(flags & XBF_READ)) | |
706 | xfs_buf_ioerror(bp, 0); | |
707 | ||
ff6d6af2 | 708 | XFS_STATS_INC(target->bt_mount, xb_get); |
0b1b213f | 709 | trace_xfs_buf_get(bp, flags, _RET_IP_); |
ce8e922c | 710 | return bp; |
1da177e4 LT |
711 | } |
712 | ||
5d765b97 CH |
713 | STATIC int |
714 | _xfs_buf_read( | |
715 | xfs_buf_t *bp, | |
716 | xfs_buf_flags_t flags) | |
717 | { | |
43ff2122 | 718 | ASSERT(!(flags & XBF_WRITE)); |
f4b42421 | 719 | ASSERT(bp->b_maps[0].bm_bn != XFS_BUF_DADDR_NULL); |
5d765b97 | 720 | |
43ff2122 | 721 | bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD); |
1d5ae5df | 722 | bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD); |
5d765b97 | 723 | |
595bff75 DC |
724 | if (flags & XBF_ASYNC) { |
725 | xfs_buf_submit(bp); | |
0e95f19a | 726 | return 0; |
595bff75 DC |
727 | } |
728 | return xfs_buf_submit_wait(bp); | |
5d765b97 CH |
729 | } |
730 | ||
1da177e4 | 731 | xfs_buf_t * |
6dde2707 DC |
732 | xfs_buf_read_map( |
733 | struct xfs_buftarg *target, | |
734 | struct xfs_buf_map *map, | |
735 | int nmaps, | |
c3f8fc73 | 736 | xfs_buf_flags_t flags, |
1813dd64 | 737 | const struct xfs_buf_ops *ops) |
1da177e4 | 738 | { |
6dde2707 | 739 | struct xfs_buf *bp; |
ce8e922c NS |
740 | |
741 | flags |= XBF_READ; | |
742 | ||
6dde2707 | 743 | bp = xfs_buf_get_map(target, map, nmaps, flags); |
ce8e922c | 744 | if (bp) { |
0b1b213f CH |
745 | trace_xfs_buf_read(bp, flags, _RET_IP_); |
746 | ||
b0388bf1 | 747 | if (!(bp->b_flags & XBF_DONE)) { |
ff6d6af2 | 748 | XFS_STATS_INC(target->bt_mount, xb_get_read); |
1813dd64 | 749 | bp->b_ops = ops; |
5d765b97 | 750 | _xfs_buf_read(bp, flags); |
ce8e922c | 751 | } else if (flags & XBF_ASYNC) { |
1da177e4 LT |
752 | /* |
753 | * Read ahead call which is already satisfied, | |
754 | * drop the buffer | |
755 | */ | |
a8acad70 DC |
756 | xfs_buf_relse(bp); |
757 | return NULL; | |
1da177e4 | 758 | } else { |
1da177e4 | 759 | /* We do not want read in the flags */ |
ce8e922c | 760 | bp->b_flags &= ~XBF_READ; |
1da177e4 LT |
761 | } |
762 | } | |
763 | ||
ce8e922c | 764 | return bp; |
1da177e4 LT |
765 | } |
766 | ||
1da177e4 | 767 | /* |
ce8e922c NS |
768 | * If we are not low on memory then do the readahead in a deadlock |
769 | * safe manner. | |
1da177e4 LT |
770 | */ |
771 | void | |
6dde2707 DC |
772 | xfs_buf_readahead_map( |
773 | struct xfs_buftarg *target, | |
774 | struct xfs_buf_map *map, | |
c3f8fc73 | 775 | int nmaps, |
1813dd64 | 776 | const struct xfs_buf_ops *ops) |
1da177e4 | 777 | { |
efa7c9f9 | 778 | if (bdi_read_congested(target->bt_bdev->bd_bdi)) |
1da177e4 LT |
779 | return; |
780 | ||
6dde2707 | 781 | xfs_buf_read_map(target, map, nmaps, |
1813dd64 | 782 | XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD, ops); |
1da177e4 LT |
783 | } |
784 | ||
5adc94c2 DC |
785 | /* |
786 | * Read an uncached buffer from disk. Allocates and returns a locked | |
787 | * buffer containing the disk contents or nothing. | |
788 | */ | |
ba372674 | 789 | int |
5adc94c2 | 790 | xfs_buf_read_uncached( |
5adc94c2 DC |
791 | struct xfs_buftarg *target, |
792 | xfs_daddr_t daddr, | |
e70b73f8 | 793 | size_t numblks, |
c3f8fc73 | 794 | int flags, |
ba372674 | 795 | struct xfs_buf **bpp, |
1813dd64 | 796 | const struct xfs_buf_ops *ops) |
5adc94c2 | 797 | { |
eab4e633 | 798 | struct xfs_buf *bp; |
5adc94c2 | 799 | |
ba372674 DC |
800 | *bpp = NULL; |
801 | ||
e70b73f8 | 802 | bp = xfs_buf_get_uncached(target, numblks, flags); |
5adc94c2 | 803 | if (!bp) |
ba372674 | 804 | return -ENOMEM; |
5adc94c2 DC |
805 | |
806 | /* set up the buffer for a read IO */ | |
3e85c868 | 807 | ASSERT(bp->b_map_count == 1); |
ba372674 | 808 | bp->b_bn = XFS_BUF_DADDR_NULL; /* always null for uncached buffers */ |
3e85c868 | 809 | bp->b_maps[0].bm_bn = daddr; |
cbb7baab | 810 | bp->b_flags |= XBF_READ; |
1813dd64 | 811 | bp->b_ops = ops; |
5adc94c2 | 812 | |
595bff75 | 813 | xfs_buf_submit_wait(bp); |
ba372674 DC |
814 | if (bp->b_error) { |
815 | int error = bp->b_error; | |
83a0adc3 | 816 | xfs_buf_relse(bp); |
ba372674 | 817 | return error; |
83a0adc3 | 818 | } |
ba372674 DC |
819 | |
820 | *bpp = bp; | |
821 | return 0; | |
1da177e4 LT |
822 | } |
823 | ||
44396476 DC |
824 | /* |
825 | * Return a buffer allocated as an empty buffer and associated to external | |
826 | * memory via xfs_buf_associate_memory() back to it's empty state. | |
827 | */ | |
828 | void | |
829 | xfs_buf_set_empty( | |
830 | struct xfs_buf *bp, | |
e70b73f8 | 831 | size_t numblks) |
44396476 DC |
832 | { |
833 | if (bp->b_pages) | |
834 | _xfs_buf_free_pages(bp); | |
835 | ||
836 | bp->b_pages = NULL; | |
837 | bp->b_page_count = 0; | |
838 | bp->b_addr = NULL; | |
4e94b71b | 839 | bp->b_length = numblks; |
aa0e8833 | 840 | bp->b_io_length = numblks; |
3e85c868 DC |
841 | |
842 | ASSERT(bp->b_map_count == 1); | |
44396476 | 843 | bp->b_bn = XFS_BUF_DADDR_NULL; |
3e85c868 DC |
844 | bp->b_maps[0].bm_bn = XFS_BUF_DADDR_NULL; |
845 | bp->b_maps[0].bm_len = bp->b_length; | |
44396476 DC |
846 | } |
847 | ||
1da177e4 LT |
848 | static inline struct page * |
849 | mem_to_page( | |
850 | void *addr) | |
851 | { | |
9e2779fa | 852 | if ((!is_vmalloc_addr(addr))) { |
1da177e4 LT |
853 | return virt_to_page(addr); |
854 | } else { | |
855 | return vmalloc_to_page(addr); | |
856 | } | |
857 | } | |
858 | ||
859 | int | |
ce8e922c NS |
860 | xfs_buf_associate_memory( |
861 | xfs_buf_t *bp, | |
1da177e4 LT |
862 | void *mem, |
863 | size_t len) | |
864 | { | |
865 | int rval; | |
866 | int i = 0; | |
d1afb678 LM |
867 | unsigned long pageaddr; |
868 | unsigned long offset; | |
869 | size_t buflen; | |
1da177e4 LT |
870 | int page_count; |
871 | ||
0e6e847f | 872 | pageaddr = (unsigned long)mem & PAGE_MASK; |
d1afb678 | 873 | offset = (unsigned long)mem - pageaddr; |
0e6e847f DC |
874 | buflen = PAGE_ALIGN(len + offset); |
875 | page_count = buflen >> PAGE_SHIFT; | |
1da177e4 LT |
876 | |
877 | /* Free any previous set of page pointers */ | |
ce8e922c NS |
878 | if (bp->b_pages) |
879 | _xfs_buf_free_pages(bp); | |
1da177e4 | 880 | |
ce8e922c NS |
881 | bp->b_pages = NULL; |
882 | bp->b_addr = mem; | |
1da177e4 | 883 | |
87937bf8 | 884 | rval = _xfs_buf_get_pages(bp, page_count); |
1da177e4 LT |
885 | if (rval) |
886 | return rval; | |
887 | ||
ce8e922c | 888 | bp->b_offset = offset; |
d1afb678 LM |
889 | |
890 | for (i = 0; i < bp->b_page_count; i++) { | |
891 | bp->b_pages[i] = mem_to_page((void *)pageaddr); | |
0e6e847f | 892 | pageaddr += PAGE_SIZE; |
1da177e4 | 893 | } |
1da177e4 | 894 | |
aa0e8833 | 895 | bp->b_io_length = BTOBB(len); |
4e94b71b | 896 | bp->b_length = BTOBB(buflen); |
1da177e4 LT |
897 | |
898 | return 0; | |
899 | } | |
900 | ||
901 | xfs_buf_t * | |
686865f7 DC |
902 | xfs_buf_get_uncached( |
903 | struct xfs_buftarg *target, | |
e70b73f8 | 904 | size_t numblks, |
686865f7 | 905 | int flags) |
1da177e4 | 906 | { |
e70b73f8 | 907 | unsigned long page_count; |
1fa40b01 | 908 | int error, i; |
3e85c868 DC |
909 | struct xfs_buf *bp; |
910 | DEFINE_SINGLE_BUF_MAP(map, XFS_BUF_DADDR_NULL, numblks); | |
1da177e4 | 911 | |
c891c30a BF |
912 | /* flags might contain irrelevant bits, pass only what we care about */ |
913 | bp = _xfs_buf_alloc(target, &map, 1, flags & XBF_NO_IOACCT); | |
1da177e4 LT |
914 | if (unlikely(bp == NULL)) |
915 | goto fail; | |
1da177e4 | 916 | |
e70b73f8 | 917 | page_count = PAGE_ALIGN(numblks << BBSHIFT) >> PAGE_SHIFT; |
87937bf8 | 918 | error = _xfs_buf_get_pages(bp, page_count); |
1fa40b01 | 919 | if (error) |
1da177e4 LT |
920 | goto fail_free_buf; |
921 | ||
1fa40b01 | 922 | for (i = 0; i < page_count; i++) { |
686865f7 | 923 | bp->b_pages[i] = alloc_page(xb_to_gfp(flags)); |
1fa40b01 CH |
924 | if (!bp->b_pages[i]) |
925 | goto fail_free_mem; | |
1da177e4 | 926 | } |
1fa40b01 | 927 | bp->b_flags |= _XBF_PAGES; |
1da177e4 | 928 | |
611c9946 | 929 | error = _xfs_buf_map_pages(bp, 0); |
1fa40b01 | 930 | if (unlikely(error)) { |
4f10700a | 931 | xfs_warn(target->bt_mount, |
08e96e1a | 932 | "%s: failed to map pages", __func__); |
1da177e4 | 933 | goto fail_free_mem; |
1fa40b01 | 934 | } |
1da177e4 | 935 | |
686865f7 | 936 | trace_xfs_buf_get_uncached(bp, _RET_IP_); |
1da177e4 | 937 | return bp; |
1fa40b01 | 938 | |
1da177e4 | 939 | fail_free_mem: |
1fa40b01 CH |
940 | while (--i >= 0) |
941 | __free_page(bp->b_pages[i]); | |
ca165b88 | 942 | _xfs_buf_free_pages(bp); |
1da177e4 | 943 | fail_free_buf: |
3e85c868 | 944 | xfs_buf_free_maps(bp); |
4347b9d7 | 945 | kmem_zone_free(xfs_buf_zone, bp); |
1da177e4 LT |
946 | fail: |
947 | return NULL; | |
948 | } | |
949 | ||
950 | /* | |
1da177e4 LT |
951 | * Increment reference count on buffer, to hold the buffer concurrently |
952 | * with another thread which may release (free) the buffer asynchronously. | |
1da177e4 LT |
953 | * Must hold the buffer already to call this function. |
954 | */ | |
955 | void | |
ce8e922c NS |
956 | xfs_buf_hold( |
957 | xfs_buf_t *bp) | |
1da177e4 | 958 | { |
0b1b213f | 959 | trace_xfs_buf_hold(bp, _RET_IP_); |
ce8e922c | 960 | atomic_inc(&bp->b_hold); |
1da177e4 LT |
961 | } |
962 | ||
963 | /* | |
9c7504aa BF |
964 | * Release a hold on the specified buffer. If the hold count is 1, the buffer is |
965 | * placed on LRU or freed (depending on b_lru_ref). | |
1da177e4 LT |
966 | */ |
967 | void | |
ce8e922c NS |
968 | xfs_buf_rele( |
969 | xfs_buf_t *bp) | |
1da177e4 | 970 | { |
74f75a0c | 971 | struct xfs_perag *pag = bp->b_pag; |
9c7504aa BF |
972 | bool release; |
973 | bool freebuf = false; | |
1da177e4 | 974 | |
0b1b213f | 975 | trace_xfs_buf_rele(bp, _RET_IP_); |
1da177e4 | 976 | |
74f75a0c | 977 | if (!pag) { |
430cbeb8 | 978 | ASSERT(list_empty(&bp->b_lru)); |
9c7504aa BF |
979 | if (atomic_dec_and_test(&bp->b_hold)) { |
980 | xfs_buf_ioacct_dec(bp); | |
fad3aa1e | 981 | xfs_buf_free(bp); |
9c7504aa | 982 | } |
fad3aa1e NS |
983 | return; |
984 | } | |
985 | ||
3790689f | 986 | ASSERT(atomic_read(&bp->b_hold) > 0); |
a4082357 | 987 | |
9c7504aa BF |
988 | release = atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock); |
989 | spin_lock(&bp->b_lock); | |
990 | if (!release) { | |
991 | /* | |
992 | * Drop the in-flight state if the buffer is already on the LRU | |
993 | * and it holds the only reference. This is racy because we | |
994 | * haven't acquired the pag lock, but the use of _XBF_IN_FLIGHT | |
995 | * ensures the decrement occurs only once per-buf. | |
996 | */ | |
997 | if ((atomic_read(&bp->b_hold) == 1) && !list_empty(&bp->b_lru)) | |
63db7c81 | 998 | __xfs_buf_ioacct_dec(bp); |
9c7504aa BF |
999 | goto out_unlock; |
1000 | } | |
1001 | ||
1002 | /* the last reference has been dropped ... */ | |
63db7c81 | 1003 | __xfs_buf_ioacct_dec(bp); |
9c7504aa BF |
1004 | if (!(bp->b_flags & XBF_STALE) && atomic_read(&bp->b_lru_ref)) { |
1005 | /* | |
1006 | * If the buffer is added to the LRU take a new reference to the | |
1007 | * buffer for the LRU and clear the (now stale) dispose list | |
1008 | * state flag | |
1009 | */ | |
1010 | if (list_lru_add(&bp->b_target->bt_lru, &bp->b_lru)) { | |
1011 | bp->b_state &= ~XFS_BSTATE_DISPOSE; | |
1012 | atomic_inc(&bp->b_hold); | |
1da177e4 | 1013 | } |
9c7504aa BF |
1014 | spin_unlock(&pag->pag_buf_lock); |
1015 | } else { | |
1016 | /* | |
1017 | * most of the time buffers will already be removed from the | |
1018 | * LRU, so optimise that case by checking for the | |
1019 | * XFS_BSTATE_DISPOSE flag indicating the last list the buffer | |
1020 | * was on was the disposal list | |
1021 | */ | |
1022 | if (!(bp->b_state & XFS_BSTATE_DISPOSE)) { | |
1023 | list_lru_del(&bp->b_target->bt_lru, &bp->b_lru); | |
1024 | } else { | |
1025 | ASSERT(list_empty(&bp->b_lru)); | |
1da177e4 | 1026 | } |
9c7504aa BF |
1027 | |
1028 | ASSERT(!(bp->b_flags & _XBF_DELWRI_Q)); | |
6031e73a LS |
1029 | rhashtable_remove_fast(&pag->pag_buf_hash, &bp->b_rhash_head, |
1030 | xfs_buf_hash_params); | |
9c7504aa BF |
1031 | spin_unlock(&pag->pag_buf_lock); |
1032 | xfs_perag_put(pag); | |
1033 | freebuf = true; | |
1da177e4 | 1034 | } |
9c7504aa BF |
1035 | |
1036 | out_unlock: | |
1037 | spin_unlock(&bp->b_lock); | |
1038 | ||
1039 | if (freebuf) | |
1040 | xfs_buf_free(bp); | |
1da177e4 LT |
1041 | } |
1042 | ||
1043 | ||
1044 | /* | |
0e6e847f | 1045 | * Lock a buffer object, if it is not already locked. |
90810b9e DC |
1046 | * |
1047 | * If we come across a stale, pinned, locked buffer, we know that we are | |
1048 | * being asked to lock a buffer that has been reallocated. Because it is | |
1049 | * pinned, we know that the log has not been pushed to disk and hence it | |
1050 | * will still be locked. Rather than continuing to have trylock attempts | |
1051 | * fail until someone else pushes the log, push it ourselves before | |
1052 | * returning. This means that the xfsaild will not get stuck trying | |
1053 | * to push on stale inode buffers. | |
1da177e4 LT |
1054 | */ |
1055 | int | |
0c842ad4 CH |
1056 | xfs_buf_trylock( |
1057 | struct xfs_buf *bp) | |
1da177e4 LT |
1058 | { |
1059 | int locked; | |
1060 | ||
ce8e922c | 1061 | locked = down_trylock(&bp->b_sema) == 0; |
479c6412 | 1062 | if (locked) { |
ce8e922c | 1063 | XB_SET_OWNER(bp); |
479c6412 DW |
1064 | trace_xfs_buf_trylock(bp, _RET_IP_); |
1065 | } else { | |
1066 | trace_xfs_buf_trylock_fail(bp, _RET_IP_); | |
1067 | } | |
0c842ad4 | 1068 | return locked; |
1da177e4 | 1069 | } |
1da177e4 LT |
1070 | |
1071 | /* | |
0e6e847f | 1072 | * Lock a buffer object. |
ed3b4d6c DC |
1073 | * |
1074 | * If we come across a stale, pinned, locked buffer, we know that we | |
1075 | * are being asked to lock a buffer that has been reallocated. Because | |
1076 | * it is pinned, we know that the log has not been pushed to disk and | |
1077 | * hence it will still be locked. Rather than sleeping until someone | |
1078 | * else pushes the log, push it ourselves before trying to get the lock. | |
1da177e4 | 1079 | */ |
ce8e922c NS |
1080 | void |
1081 | xfs_buf_lock( | |
0c842ad4 | 1082 | struct xfs_buf *bp) |
1da177e4 | 1083 | { |
0b1b213f CH |
1084 | trace_xfs_buf_lock(bp, _RET_IP_); |
1085 | ||
ed3b4d6c | 1086 | if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE)) |
ebad861b | 1087 | xfs_log_force(bp->b_target->bt_mount, 0); |
ce8e922c NS |
1088 | down(&bp->b_sema); |
1089 | XB_SET_OWNER(bp); | |
0b1b213f CH |
1090 | |
1091 | trace_xfs_buf_lock_done(bp, _RET_IP_); | |
1da177e4 LT |
1092 | } |
1093 | ||
1da177e4 | 1094 | void |
ce8e922c | 1095 | xfs_buf_unlock( |
0c842ad4 | 1096 | struct xfs_buf *bp) |
1da177e4 | 1097 | { |
20e8a063 BF |
1098 | ASSERT(xfs_buf_islocked(bp)); |
1099 | ||
ce8e922c NS |
1100 | XB_CLEAR_OWNER(bp); |
1101 | up(&bp->b_sema); | |
0b1b213f CH |
1102 | |
1103 | trace_xfs_buf_unlock(bp, _RET_IP_); | |
1da177e4 LT |
1104 | } |
1105 | ||
ce8e922c NS |
1106 | STATIC void |
1107 | xfs_buf_wait_unpin( | |
1108 | xfs_buf_t *bp) | |
1da177e4 LT |
1109 | { |
1110 | DECLARE_WAITQUEUE (wait, current); | |
1111 | ||
ce8e922c | 1112 | if (atomic_read(&bp->b_pin_count) == 0) |
1da177e4 LT |
1113 | return; |
1114 | ||
ce8e922c | 1115 | add_wait_queue(&bp->b_waiters, &wait); |
1da177e4 LT |
1116 | for (;;) { |
1117 | set_current_state(TASK_UNINTERRUPTIBLE); | |
ce8e922c | 1118 | if (atomic_read(&bp->b_pin_count) == 0) |
1da177e4 | 1119 | break; |
7eaceacc | 1120 | io_schedule(); |
1da177e4 | 1121 | } |
ce8e922c | 1122 | remove_wait_queue(&bp->b_waiters, &wait); |
1da177e4 LT |
1123 | set_current_state(TASK_RUNNING); |
1124 | } | |
1125 | ||
1126 | /* | |
1127 | * Buffer Utility Routines | |
1128 | */ | |
1129 | ||
e8aaba9a DC |
1130 | void |
1131 | xfs_buf_ioend( | |
1132 | struct xfs_buf *bp) | |
1da177e4 | 1133 | { |
e8aaba9a DC |
1134 | bool read = bp->b_flags & XBF_READ; |
1135 | ||
1136 | trace_xfs_buf_iodone(bp, _RET_IP_); | |
1813dd64 DC |
1137 | |
1138 | bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD); | |
d5929de8 | 1139 | |
61be9c52 DC |
1140 | /* |
1141 | * Pull in IO completion errors now. We are guaranteed to be running | |
1142 | * single threaded, so we don't need the lock to read b_io_error. | |
1143 | */ | |
1144 | if (!bp->b_error && bp->b_io_error) | |
1145 | xfs_buf_ioerror(bp, bp->b_io_error); | |
1146 | ||
e8aaba9a DC |
1147 | /* Only validate buffers that were read without errors */ |
1148 | if (read && !bp->b_error && bp->b_ops) { | |
1149 | ASSERT(!bp->b_iodone); | |
1813dd64 | 1150 | bp->b_ops->verify_read(bp); |
e8aaba9a DC |
1151 | } |
1152 | ||
1153 | if (!bp->b_error) | |
1154 | bp->b_flags |= XBF_DONE; | |
1da177e4 | 1155 | |
80f6c29d | 1156 | if (bp->b_iodone) |
ce8e922c NS |
1157 | (*(bp->b_iodone))(bp); |
1158 | else if (bp->b_flags & XBF_ASYNC) | |
1da177e4 | 1159 | xfs_buf_relse(bp); |
595bff75 | 1160 | else |
1813dd64 | 1161 | complete(&bp->b_iowait); |
1da177e4 LT |
1162 | } |
1163 | ||
e8aaba9a DC |
1164 | static void |
1165 | xfs_buf_ioend_work( | |
1166 | struct work_struct *work) | |
1da177e4 | 1167 | { |
e8aaba9a | 1168 | struct xfs_buf *bp = |
b29c70f5 | 1169 | container_of(work, xfs_buf_t, b_ioend_work); |
0b1b213f | 1170 | |
e8aaba9a DC |
1171 | xfs_buf_ioend(bp); |
1172 | } | |
1da177e4 | 1173 | |
211fe1a4 | 1174 | static void |
e8aaba9a DC |
1175 | xfs_buf_ioend_async( |
1176 | struct xfs_buf *bp) | |
1177 | { | |
b29c70f5 BF |
1178 | INIT_WORK(&bp->b_ioend_work, xfs_buf_ioend_work); |
1179 | queue_work(bp->b_ioend_wq, &bp->b_ioend_work); | |
1da177e4 LT |
1180 | } |
1181 | ||
1da177e4 | 1182 | void |
ce8e922c NS |
1183 | xfs_buf_ioerror( |
1184 | xfs_buf_t *bp, | |
1185 | int error) | |
1da177e4 | 1186 | { |
2451337d DC |
1187 | ASSERT(error <= 0 && error >= -1000); |
1188 | bp->b_error = error; | |
0b1b213f | 1189 | trace_xfs_buf_ioerror(bp, error, _RET_IP_); |
1da177e4 LT |
1190 | } |
1191 | ||
901796af CH |
1192 | void |
1193 | xfs_buf_ioerror_alert( | |
1194 | struct xfs_buf *bp, | |
1195 | const char *func) | |
1196 | { | |
1197 | xfs_alert(bp->b_target->bt_mount, | |
aa0e8833 | 1198 | "metadata I/O error: block 0x%llx (\"%s\") error %d numblks %d", |
c8ce540d | 1199 | (uint64_t)XFS_BUF_ADDR(bp), func, -bp->b_error, bp->b_length); |
901796af CH |
1200 | } |
1201 | ||
a2dcf5df CH |
1202 | int |
1203 | xfs_bwrite( | |
1204 | struct xfs_buf *bp) | |
1205 | { | |
1206 | int error; | |
1207 | ||
1208 | ASSERT(xfs_buf_islocked(bp)); | |
1209 | ||
1210 | bp->b_flags |= XBF_WRITE; | |
27187754 DC |
1211 | bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q | |
1212 | XBF_WRITE_FAIL | XBF_DONE); | |
a2dcf5df | 1213 | |
595bff75 | 1214 | error = xfs_buf_submit_wait(bp); |
a2dcf5df CH |
1215 | if (error) { |
1216 | xfs_force_shutdown(bp->b_target->bt_mount, | |
1217 | SHUTDOWN_META_IO_ERROR); | |
1218 | } | |
1219 | return error; | |
1220 | } | |
1221 | ||
9bdd9bd6 | 1222 | static void |
ce8e922c | 1223 | xfs_buf_bio_end_io( |
4246a0b6 | 1224 | struct bio *bio) |
1da177e4 | 1225 | { |
9bdd9bd6 | 1226 | struct xfs_buf *bp = (struct xfs_buf *)bio->bi_private; |
1da177e4 | 1227 | |
37eb17e6 DC |
1228 | /* |
1229 | * don't overwrite existing errors - otherwise we can lose errors on | |
1230 | * buffers that require multiple bios to complete. | |
1231 | */ | |
4e4cbee9 CH |
1232 | if (bio->bi_status) { |
1233 | int error = blk_status_to_errno(bio->bi_status); | |
1234 | ||
1235 | cmpxchg(&bp->b_io_error, 0, error); | |
1236 | } | |
1da177e4 | 1237 | |
37eb17e6 | 1238 | if (!bp->b_error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ)) |
73c77e2c JB |
1239 | invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp)); |
1240 | ||
e8aaba9a DC |
1241 | if (atomic_dec_and_test(&bp->b_io_remaining) == 1) |
1242 | xfs_buf_ioend_async(bp); | |
1da177e4 | 1243 | bio_put(bio); |
1da177e4 LT |
1244 | } |
1245 | ||
3e85c868 DC |
1246 | static void |
1247 | xfs_buf_ioapply_map( | |
1248 | struct xfs_buf *bp, | |
1249 | int map, | |
1250 | int *buf_offset, | |
1251 | int *count, | |
50bfcd0c MC |
1252 | int op, |
1253 | int op_flags) | |
1da177e4 | 1254 | { |
3e85c868 DC |
1255 | int page_index; |
1256 | int total_nr_pages = bp->b_page_count; | |
1257 | int nr_pages; | |
1258 | struct bio *bio; | |
1259 | sector_t sector = bp->b_maps[map].bm_bn; | |
1260 | int size; | |
1261 | int offset; | |
1da177e4 | 1262 | |
3e85c868 DC |
1263 | /* skip the pages in the buffer before the start offset */ |
1264 | page_index = 0; | |
1265 | offset = *buf_offset; | |
1266 | while (offset >= PAGE_SIZE) { | |
1267 | page_index++; | |
1268 | offset -= PAGE_SIZE; | |
f538d4da CH |
1269 | } |
1270 | ||
3e85c868 DC |
1271 | /* |
1272 | * Limit the IO size to the length of the current vector, and update the | |
1273 | * remaining IO count for the next time around. | |
1274 | */ | |
1275 | size = min_t(int, BBTOB(bp->b_maps[map].bm_len), *count); | |
1276 | *count -= size; | |
1277 | *buf_offset += size; | |
34951f5c | 1278 | |
1da177e4 | 1279 | next_chunk: |
ce8e922c | 1280 | atomic_inc(&bp->b_io_remaining); |
c908e380 | 1281 | nr_pages = min(total_nr_pages, BIO_MAX_PAGES); |
1da177e4 LT |
1282 | |
1283 | bio = bio_alloc(GFP_NOIO, nr_pages); | |
74d46992 | 1284 | bio_set_dev(bio, bp->b_target->bt_bdev); |
4f024f37 | 1285 | bio->bi_iter.bi_sector = sector; |
ce8e922c NS |
1286 | bio->bi_end_io = xfs_buf_bio_end_io; |
1287 | bio->bi_private = bp; | |
50bfcd0c | 1288 | bio_set_op_attrs(bio, op, op_flags); |
0e6e847f | 1289 | |
3e85c868 | 1290 | for (; size && nr_pages; nr_pages--, page_index++) { |
0e6e847f | 1291 | int rbytes, nbytes = PAGE_SIZE - offset; |
1da177e4 LT |
1292 | |
1293 | if (nbytes > size) | |
1294 | nbytes = size; | |
1295 | ||
3e85c868 DC |
1296 | rbytes = bio_add_page(bio, bp->b_pages[page_index], nbytes, |
1297 | offset); | |
ce8e922c | 1298 | if (rbytes < nbytes) |
1da177e4 LT |
1299 | break; |
1300 | ||
1301 | offset = 0; | |
aa0e8833 | 1302 | sector += BTOBB(nbytes); |
1da177e4 LT |
1303 | size -= nbytes; |
1304 | total_nr_pages--; | |
1305 | } | |
1306 | ||
4f024f37 | 1307 | if (likely(bio->bi_iter.bi_size)) { |
73c77e2c JB |
1308 | if (xfs_buf_is_vmapped(bp)) { |
1309 | flush_kernel_vmap_range(bp->b_addr, | |
1310 | xfs_buf_vmap_len(bp)); | |
1311 | } | |
4e49ea4a | 1312 | submit_bio(bio); |
1da177e4 LT |
1313 | if (size) |
1314 | goto next_chunk; | |
1315 | } else { | |
37eb17e6 DC |
1316 | /* |
1317 | * This is guaranteed not to be the last io reference count | |
595bff75 | 1318 | * because the caller (xfs_buf_submit) holds a count itself. |
37eb17e6 DC |
1319 | */ |
1320 | atomic_dec(&bp->b_io_remaining); | |
2451337d | 1321 | xfs_buf_ioerror(bp, -EIO); |
ec53d1db | 1322 | bio_put(bio); |
1da177e4 | 1323 | } |
3e85c868 DC |
1324 | |
1325 | } | |
1326 | ||
1327 | STATIC void | |
1328 | _xfs_buf_ioapply( | |
1329 | struct xfs_buf *bp) | |
1330 | { | |
1331 | struct blk_plug plug; | |
50bfcd0c MC |
1332 | int op; |
1333 | int op_flags = 0; | |
3e85c868 DC |
1334 | int offset; |
1335 | int size; | |
1336 | int i; | |
1337 | ||
c163f9a1 DC |
1338 | /* |
1339 | * Make sure we capture only current IO errors rather than stale errors | |
1340 | * left over from previous use of the buffer (e.g. failed readahead). | |
1341 | */ | |
1342 | bp->b_error = 0; | |
1343 | ||
b29c70f5 BF |
1344 | /* |
1345 | * Initialize the I/O completion workqueue if we haven't yet or the | |
1346 | * submitter has not opted to specify a custom one. | |
1347 | */ | |
1348 | if (!bp->b_ioend_wq) | |
1349 | bp->b_ioend_wq = bp->b_target->bt_mount->m_buf_workqueue; | |
1350 | ||
3e85c868 | 1351 | if (bp->b_flags & XBF_WRITE) { |
50bfcd0c | 1352 | op = REQ_OP_WRITE; |
3e85c868 | 1353 | if (bp->b_flags & XBF_SYNCIO) |
70fd7614 | 1354 | op_flags = REQ_SYNC; |
3e85c868 | 1355 | if (bp->b_flags & XBF_FUA) |
50bfcd0c | 1356 | op_flags |= REQ_FUA; |
3e85c868 | 1357 | if (bp->b_flags & XBF_FLUSH) |
28a8f0d3 | 1358 | op_flags |= REQ_PREFLUSH; |
1813dd64 DC |
1359 | |
1360 | /* | |
1361 | * Run the write verifier callback function if it exists. If | |
1362 | * this function fails it will mark the buffer with an error and | |
1363 | * the IO should not be dispatched. | |
1364 | */ | |
1365 | if (bp->b_ops) { | |
1366 | bp->b_ops->verify_write(bp); | |
1367 | if (bp->b_error) { | |
1368 | xfs_force_shutdown(bp->b_target->bt_mount, | |
1369 | SHUTDOWN_CORRUPT_INCORE); | |
1370 | return; | |
1371 | } | |
400b9d88 DC |
1372 | } else if (bp->b_bn != XFS_BUF_DADDR_NULL) { |
1373 | struct xfs_mount *mp = bp->b_target->bt_mount; | |
1374 | ||
1375 | /* | |
1376 | * non-crc filesystems don't attach verifiers during | |
1377 | * log recovery, so don't warn for such filesystems. | |
1378 | */ | |
1379 | if (xfs_sb_version_hascrc(&mp->m_sb)) { | |
1380 | xfs_warn(mp, | |
1381 | "%s: no ops on block 0x%llx/0x%x", | |
1382 | __func__, bp->b_bn, bp->b_length); | |
1383 | xfs_hex_dump(bp->b_addr, 64); | |
1384 | dump_stack(); | |
1385 | } | |
1813dd64 | 1386 | } |
3e85c868 | 1387 | } else if (bp->b_flags & XBF_READ_AHEAD) { |
50bfcd0c MC |
1388 | op = REQ_OP_READ; |
1389 | op_flags = REQ_RAHEAD; | |
3e85c868 | 1390 | } else { |
50bfcd0c | 1391 | op = REQ_OP_READ; |
3e85c868 DC |
1392 | } |
1393 | ||
1394 | /* we only use the buffer cache for meta-data */ | |
50bfcd0c | 1395 | op_flags |= REQ_META; |
3e85c868 DC |
1396 | |
1397 | /* | |
1398 | * Walk all the vectors issuing IO on them. Set up the initial offset | |
1399 | * into the buffer and the desired IO size before we start - | |
1400 | * _xfs_buf_ioapply_vec() will modify them appropriately for each | |
1401 | * subsequent call. | |
1402 | */ | |
1403 | offset = bp->b_offset; | |
1404 | size = BBTOB(bp->b_io_length); | |
1405 | blk_start_plug(&plug); | |
1406 | for (i = 0; i < bp->b_map_count; i++) { | |
50bfcd0c | 1407 | xfs_buf_ioapply_map(bp, i, &offset, &size, op, op_flags); |
3e85c868 DC |
1408 | if (bp->b_error) |
1409 | break; | |
1410 | if (size <= 0) | |
1411 | break; /* all done */ | |
1412 | } | |
1413 | blk_finish_plug(&plug); | |
1da177e4 LT |
1414 | } |
1415 | ||
595bff75 DC |
1416 | /* |
1417 | * Asynchronous IO submission path. This transfers the buffer lock ownership and | |
1418 | * the current reference to the IO. It is not safe to reference the buffer after | |
1419 | * a call to this function unless the caller holds an additional reference | |
1420 | * itself. | |
1421 | */ | |
0e95f19a | 1422 | void |
595bff75 DC |
1423 | xfs_buf_submit( |
1424 | struct xfs_buf *bp) | |
1da177e4 | 1425 | { |
595bff75 | 1426 | trace_xfs_buf_submit(bp, _RET_IP_); |
1da177e4 | 1427 | |
43ff2122 | 1428 | ASSERT(!(bp->b_flags & _XBF_DELWRI_Q)); |
595bff75 DC |
1429 | ASSERT(bp->b_flags & XBF_ASYNC); |
1430 | ||
1431 | /* on shutdown we stale and complete the buffer immediately */ | |
1432 | if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) { | |
1433 | xfs_buf_ioerror(bp, -EIO); | |
1434 | bp->b_flags &= ~XBF_DONE; | |
1435 | xfs_buf_stale(bp); | |
1436 | xfs_buf_ioend(bp); | |
1437 | return; | |
1438 | } | |
1da177e4 | 1439 | |
375ec69d | 1440 | if (bp->b_flags & XBF_WRITE) |
ce8e922c | 1441 | xfs_buf_wait_unpin(bp); |
e11bb805 | 1442 | |
61be9c52 DC |
1443 | /* clear the internal error state to avoid spurious errors */ |
1444 | bp->b_io_error = 0; | |
1445 | ||
e11bb805 | 1446 | /* |
595bff75 DC |
1447 | * The caller's reference is released during I/O completion. |
1448 | * This occurs some time after the last b_io_remaining reference is | |
1449 | * released, so after we drop our Io reference we have to have some | |
1450 | * other reference to ensure the buffer doesn't go away from underneath | |
1451 | * us. Take a direct reference to ensure we have safe access to the | |
1452 | * buffer until we are finished with it. | |
e11bb805 | 1453 | */ |
ce8e922c | 1454 | xfs_buf_hold(bp); |
1da177e4 | 1455 | |
8d6c1210 | 1456 | /* |
e11bb805 DC |
1457 | * Set the count to 1 initially, this will stop an I/O completion |
1458 | * callout which happens before we have started all the I/O from calling | |
1459 | * xfs_buf_ioend too early. | |
1da177e4 | 1460 | */ |
ce8e922c | 1461 | atomic_set(&bp->b_io_remaining, 1); |
9c7504aa | 1462 | xfs_buf_ioacct_inc(bp); |
ce8e922c | 1463 | _xfs_buf_ioapply(bp); |
e11bb805 | 1464 | |
8d6c1210 | 1465 | /* |
595bff75 DC |
1466 | * If _xfs_buf_ioapply failed, we can get back here with only the IO |
1467 | * reference we took above. If we drop it to zero, run completion so | |
1468 | * that we don't return to the caller with completion still pending. | |
8d6c1210 | 1469 | */ |
e8aaba9a | 1470 | if (atomic_dec_and_test(&bp->b_io_remaining) == 1) { |
595bff75 | 1471 | if (bp->b_error) |
e8aaba9a DC |
1472 | xfs_buf_ioend(bp); |
1473 | else | |
1474 | xfs_buf_ioend_async(bp); | |
1475 | } | |
1da177e4 | 1476 | |
ce8e922c | 1477 | xfs_buf_rele(bp); |
595bff75 | 1478 | /* Note: it is not safe to reference bp now we've dropped our ref */ |
1da177e4 LT |
1479 | } |
1480 | ||
1481 | /* | |
595bff75 | 1482 | * Synchronous buffer IO submission path, read or write. |
1da177e4 LT |
1483 | */ |
1484 | int | |
595bff75 DC |
1485 | xfs_buf_submit_wait( |
1486 | struct xfs_buf *bp) | |
1da177e4 | 1487 | { |
595bff75 | 1488 | int error; |
0b1b213f | 1489 | |
595bff75 DC |
1490 | trace_xfs_buf_submit_wait(bp, _RET_IP_); |
1491 | ||
1492 | ASSERT(!(bp->b_flags & (_XBF_DELWRI_Q | XBF_ASYNC))); | |
0b1b213f | 1493 | |
595bff75 DC |
1494 | if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) { |
1495 | xfs_buf_ioerror(bp, -EIO); | |
1496 | xfs_buf_stale(bp); | |
1497 | bp->b_flags &= ~XBF_DONE; | |
1498 | return -EIO; | |
1499 | } | |
1500 | ||
1501 | if (bp->b_flags & XBF_WRITE) | |
1502 | xfs_buf_wait_unpin(bp); | |
1503 | ||
1504 | /* clear the internal error state to avoid spurious errors */ | |
1505 | bp->b_io_error = 0; | |
1506 | ||
1507 | /* | |
1508 | * For synchronous IO, the IO does not inherit the submitters reference | |
1509 | * count, nor the buffer lock. Hence we cannot release the reference we | |
1510 | * are about to take until we've waited for all IO completion to occur, | |
1511 | * including any xfs_buf_ioend_async() work that may be pending. | |
1512 | */ | |
1513 | xfs_buf_hold(bp); | |
1514 | ||
1515 | /* | |
1516 | * Set the count to 1 initially, this will stop an I/O completion | |
1517 | * callout which happens before we have started all the I/O from calling | |
1518 | * xfs_buf_ioend too early. | |
1519 | */ | |
1520 | atomic_set(&bp->b_io_remaining, 1); | |
1521 | _xfs_buf_ioapply(bp); | |
1522 | ||
1523 | /* | |
1524 | * make sure we run completion synchronously if it raced with us and is | |
1525 | * already complete. | |
1526 | */ | |
1527 | if (atomic_dec_and_test(&bp->b_io_remaining) == 1) | |
1528 | xfs_buf_ioend(bp); | |
0b1b213f | 1529 | |
595bff75 DC |
1530 | /* wait for completion before gathering the error from the buffer */ |
1531 | trace_xfs_buf_iowait(bp, _RET_IP_); | |
1532 | wait_for_completion(&bp->b_iowait); | |
0b1b213f | 1533 | trace_xfs_buf_iowait_done(bp, _RET_IP_); |
595bff75 DC |
1534 | error = bp->b_error; |
1535 | ||
1536 | /* | |
1537 | * all done now, we can release the hold that keeps the buffer | |
1538 | * referenced for the entire IO. | |
1539 | */ | |
1540 | xfs_buf_rele(bp); | |
1541 | return error; | |
1da177e4 LT |
1542 | } |
1543 | ||
88ee2df7 | 1544 | void * |
ce8e922c | 1545 | xfs_buf_offset( |
88ee2df7 | 1546 | struct xfs_buf *bp, |
1da177e4 LT |
1547 | size_t offset) |
1548 | { | |
1549 | struct page *page; | |
1550 | ||
611c9946 | 1551 | if (bp->b_addr) |
62926044 | 1552 | return bp->b_addr + offset; |
1da177e4 | 1553 | |
ce8e922c | 1554 | offset += bp->b_offset; |
0e6e847f | 1555 | page = bp->b_pages[offset >> PAGE_SHIFT]; |
88ee2df7 | 1556 | return page_address(page) + (offset & (PAGE_SIZE-1)); |
1da177e4 LT |
1557 | } |
1558 | ||
1559 | /* | |
1da177e4 LT |
1560 | * Move data into or out of a buffer. |
1561 | */ | |
1562 | void | |
ce8e922c NS |
1563 | xfs_buf_iomove( |
1564 | xfs_buf_t *bp, /* buffer to process */ | |
1da177e4 LT |
1565 | size_t boff, /* starting buffer offset */ |
1566 | size_t bsize, /* length to copy */ | |
b9c48649 | 1567 | void *data, /* data address */ |
ce8e922c | 1568 | xfs_buf_rw_t mode) /* read/write/zero flag */ |
1da177e4 | 1569 | { |
795cac72 | 1570 | size_t bend; |
1da177e4 LT |
1571 | |
1572 | bend = boff + bsize; | |
1573 | while (boff < bend) { | |
795cac72 DC |
1574 | struct page *page; |
1575 | int page_index, page_offset, csize; | |
1576 | ||
1577 | page_index = (boff + bp->b_offset) >> PAGE_SHIFT; | |
1578 | page_offset = (boff + bp->b_offset) & ~PAGE_MASK; | |
1579 | page = bp->b_pages[page_index]; | |
1580 | csize = min_t(size_t, PAGE_SIZE - page_offset, | |
1581 | BBTOB(bp->b_io_length) - boff); | |
1da177e4 | 1582 | |
795cac72 | 1583 | ASSERT((csize + page_offset) <= PAGE_SIZE); |
1da177e4 LT |
1584 | |
1585 | switch (mode) { | |
ce8e922c | 1586 | case XBRW_ZERO: |
795cac72 | 1587 | memset(page_address(page) + page_offset, 0, csize); |
1da177e4 | 1588 | break; |
ce8e922c | 1589 | case XBRW_READ: |
795cac72 | 1590 | memcpy(data, page_address(page) + page_offset, csize); |
1da177e4 | 1591 | break; |
ce8e922c | 1592 | case XBRW_WRITE: |
795cac72 | 1593 | memcpy(page_address(page) + page_offset, data, csize); |
1da177e4 LT |
1594 | } |
1595 | ||
1596 | boff += csize; | |
1597 | data += csize; | |
1598 | } | |
1599 | } | |
1600 | ||
1601 | /* | |
ce8e922c | 1602 | * Handling of buffer targets (buftargs). |
1da177e4 LT |
1603 | */ |
1604 | ||
1605 | /* | |
430cbeb8 DC |
1606 | * Wait for any bufs with callbacks that have been submitted but have not yet |
1607 | * returned. These buffers will have an elevated hold count, so wait on those | |
1608 | * while freeing all the buffers only held by the LRU. | |
1da177e4 | 1609 | */ |
e80dfa19 DC |
1610 | static enum lru_status |
1611 | xfs_buftarg_wait_rele( | |
1612 | struct list_head *item, | |
3f97b163 | 1613 | struct list_lru_one *lru, |
e80dfa19 DC |
1614 | spinlock_t *lru_lock, |
1615 | void *arg) | |
1616 | ||
1da177e4 | 1617 | { |
e80dfa19 | 1618 | struct xfs_buf *bp = container_of(item, struct xfs_buf, b_lru); |
a4082357 | 1619 | struct list_head *dispose = arg; |
430cbeb8 | 1620 | |
e80dfa19 | 1621 | if (atomic_read(&bp->b_hold) > 1) { |
a4082357 | 1622 | /* need to wait, so skip it this pass */ |
e80dfa19 | 1623 | trace_xfs_buf_wait_buftarg(bp, _RET_IP_); |
a4082357 | 1624 | return LRU_SKIP; |
1da177e4 | 1625 | } |
a4082357 DC |
1626 | if (!spin_trylock(&bp->b_lock)) |
1627 | return LRU_SKIP; | |
e80dfa19 | 1628 | |
a4082357 DC |
1629 | /* |
1630 | * clear the LRU reference count so the buffer doesn't get | |
1631 | * ignored in xfs_buf_rele(). | |
1632 | */ | |
1633 | atomic_set(&bp->b_lru_ref, 0); | |
1634 | bp->b_state |= XFS_BSTATE_DISPOSE; | |
3f97b163 | 1635 | list_lru_isolate_move(lru, item, dispose); |
a4082357 DC |
1636 | spin_unlock(&bp->b_lock); |
1637 | return LRU_REMOVED; | |
1da177e4 LT |
1638 | } |
1639 | ||
e80dfa19 DC |
1640 | void |
1641 | xfs_wait_buftarg( | |
1642 | struct xfs_buftarg *btp) | |
1643 | { | |
a4082357 DC |
1644 | LIST_HEAD(dispose); |
1645 | int loop = 0; | |
1646 | ||
85bec546 | 1647 | /* |
9c7504aa BF |
1648 | * First wait on the buftarg I/O count for all in-flight buffers to be |
1649 | * released. This is critical as new buffers do not make the LRU until | |
1650 | * they are released. | |
1651 | * | |
1652 | * Next, flush the buffer workqueue to ensure all completion processing | |
1653 | * has finished. Just waiting on buffer locks is not sufficient for | |
1654 | * async IO as the reference count held over IO is not released until | |
1655 | * after the buffer lock is dropped. Hence we need to ensure here that | |
1656 | * all reference counts have been dropped before we start walking the | |
1657 | * LRU list. | |
85bec546 | 1658 | */ |
9c7504aa BF |
1659 | while (percpu_counter_sum(&btp->bt_io_count)) |
1660 | delay(100); | |
800b2694 | 1661 | flush_workqueue(btp->bt_mount->m_buf_workqueue); |
85bec546 | 1662 | |
a4082357 DC |
1663 | /* loop until there is nothing left on the lru list. */ |
1664 | while (list_lru_count(&btp->bt_lru)) { | |
e80dfa19 | 1665 | list_lru_walk(&btp->bt_lru, xfs_buftarg_wait_rele, |
a4082357 DC |
1666 | &dispose, LONG_MAX); |
1667 | ||
1668 | while (!list_empty(&dispose)) { | |
1669 | struct xfs_buf *bp; | |
1670 | bp = list_first_entry(&dispose, struct xfs_buf, b_lru); | |
1671 | list_del_init(&bp->b_lru); | |
ac8809f9 DC |
1672 | if (bp->b_flags & XBF_WRITE_FAIL) { |
1673 | xfs_alert(btp->bt_mount, | |
f41febd2 | 1674 | "Corruption Alert: Buffer at block 0x%llx had permanent write failures!", |
ac8809f9 | 1675 | (long long)bp->b_bn); |
f41febd2 JP |
1676 | xfs_alert(btp->bt_mount, |
1677 | "Please run xfs_repair to determine the extent of the problem."); | |
ac8809f9 | 1678 | } |
a4082357 DC |
1679 | xfs_buf_rele(bp); |
1680 | } | |
1681 | if (loop++ != 0) | |
1682 | delay(100); | |
1683 | } | |
e80dfa19 DC |
1684 | } |
1685 | ||
1686 | static enum lru_status | |
1687 | xfs_buftarg_isolate( | |
1688 | struct list_head *item, | |
3f97b163 | 1689 | struct list_lru_one *lru, |
e80dfa19 DC |
1690 | spinlock_t *lru_lock, |
1691 | void *arg) | |
1692 | { | |
1693 | struct xfs_buf *bp = container_of(item, struct xfs_buf, b_lru); | |
1694 | struct list_head *dispose = arg; | |
1695 | ||
a4082357 DC |
1696 | /* |
1697 | * we are inverting the lru lock/bp->b_lock here, so use a trylock. | |
1698 | * If we fail to get the lock, just skip it. | |
1699 | */ | |
1700 | if (!spin_trylock(&bp->b_lock)) | |
1701 | return LRU_SKIP; | |
e80dfa19 DC |
1702 | /* |
1703 | * Decrement the b_lru_ref count unless the value is already | |
1704 | * zero. If the value is already zero, we need to reclaim the | |
1705 | * buffer, otherwise it gets another trip through the LRU. | |
1706 | */ | |
a4082357 DC |
1707 | if (!atomic_add_unless(&bp->b_lru_ref, -1, 0)) { |
1708 | spin_unlock(&bp->b_lock); | |
e80dfa19 | 1709 | return LRU_ROTATE; |
a4082357 | 1710 | } |
e80dfa19 | 1711 | |
a4082357 | 1712 | bp->b_state |= XFS_BSTATE_DISPOSE; |
3f97b163 | 1713 | list_lru_isolate_move(lru, item, dispose); |
a4082357 | 1714 | spin_unlock(&bp->b_lock); |
e80dfa19 DC |
1715 | return LRU_REMOVED; |
1716 | } | |
1717 | ||
addbda40 | 1718 | static unsigned long |
e80dfa19 | 1719 | xfs_buftarg_shrink_scan( |
ff57ab21 | 1720 | struct shrinker *shrink, |
1495f230 | 1721 | struct shrink_control *sc) |
a6867a68 | 1722 | { |
ff57ab21 DC |
1723 | struct xfs_buftarg *btp = container_of(shrink, |
1724 | struct xfs_buftarg, bt_shrinker); | |
430cbeb8 | 1725 | LIST_HEAD(dispose); |
addbda40 | 1726 | unsigned long freed; |
430cbeb8 | 1727 | |
503c358c VD |
1728 | freed = list_lru_shrink_walk(&btp->bt_lru, sc, |
1729 | xfs_buftarg_isolate, &dispose); | |
430cbeb8 DC |
1730 | |
1731 | while (!list_empty(&dispose)) { | |
e80dfa19 | 1732 | struct xfs_buf *bp; |
430cbeb8 DC |
1733 | bp = list_first_entry(&dispose, struct xfs_buf, b_lru); |
1734 | list_del_init(&bp->b_lru); | |
1735 | xfs_buf_rele(bp); | |
1736 | } | |
1737 | ||
e80dfa19 DC |
1738 | return freed; |
1739 | } | |
1740 | ||
addbda40 | 1741 | static unsigned long |
e80dfa19 DC |
1742 | xfs_buftarg_shrink_count( |
1743 | struct shrinker *shrink, | |
1744 | struct shrink_control *sc) | |
1745 | { | |
1746 | struct xfs_buftarg *btp = container_of(shrink, | |
1747 | struct xfs_buftarg, bt_shrinker); | |
503c358c | 1748 | return list_lru_shrink_count(&btp->bt_lru, sc); |
a6867a68 DC |
1749 | } |
1750 | ||
1da177e4 LT |
1751 | void |
1752 | xfs_free_buftarg( | |
b7963133 CH |
1753 | struct xfs_mount *mp, |
1754 | struct xfs_buftarg *btp) | |
1da177e4 | 1755 | { |
ff57ab21 | 1756 | unregister_shrinker(&btp->bt_shrinker); |
9c7504aa BF |
1757 | ASSERT(percpu_counter_sum(&btp->bt_io_count) == 0); |
1758 | percpu_counter_destroy(&btp->bt_io_count); | |
f5e1dd34 | 1759 | list_lru_destroy(&btp->bt_lru); |
ff57ab21 | 1760 | |
2291dab2 | 1761 | xfs_blkdev_issue_flush(btp); |
a6867a68 | 1762 | |
f0e2d93c | 1763 | kmem_free(btp); |
1da177e4 LT |
1764 | } |
1765 | ||
3fefdeee ES |
1766 | int |
1767 | xfs_setsize_buftarg( | |
1da177e4 | 1768 | xfs_buftarg_t *btp, |
3fefdeee | 1769 | unsigned int sectorsize) |
1da177e4 | 1770 | { |
7c71ee78 | 1771 | /* Set up metadata sector size info */ |
6da54179 ES |
1772 | btp->bt_meta_sectorsize = sectorsize; |
1773 | btp->bt_meta_sectormask = sectorsize - 1; | |
1da177e4 | 1774 | |
ce8e922c | 1775 | if (set_blocksize(btp->bt_bdev, sectorsize)) { |
4f10700a | 1776 | xfs_warn(btp->bt_mount, |
a1c6f057 DM |
1777 | "Cannot set_blocksize to %u on device %pg", |
1778 | sectorsize, btp->bt_bdev); | |
2451337d | 1779 | return -EINVAL; |
1da177e4 LT |
1780 | } |
1781 | ||
7c71ee78 ES |
1782 | /* Set up device logical sector size mask */ |
1783 | btp->bt_logical_sectorsize = bdev_logical_block_size(btp->bt_bdev); | |
1784 | btp->bt_logical_sectormask = bdev_logical_block_size(btp->bt_bdev) - 1; | |
1785 | ||
1da177e4 LT |
1786 | return 0; |
1787 | } | |
1788 | ||
1789 | /* | |
3fefdeee ES |
1790 | * When allocating the initial buffer target we have not yet |
1791 | * read in the superblock, so don't know what sized sectors | |
1792 | * are being used at this early stage. Play safe. | |
ce8e922c | 1793 | */ |
1da177e4 LT |
1794 | STATIC int |
1795 | xfs_setsize_buftarg_early( | |
1796 | xfs_buftarg_t *btp, | |
1797 | struct block_device *bdev) | |
1798 | { | |
a96c4151 | 1799 | return xfs_setsize_buftarg(btp, bdev_logical_block_size(bdev)); |
1da177e4 LT |
1800 | } |
1801 | ||
1da177e4 LT |
1802 | xfs_buftarg_t * |
1803 | xfs_alloc_buftarg( | |
ebad861b | 1804 | struct xfs_mount *mp, |
486aff5e DW |
1805 | struct block_device *bdev, |
1806 | struct dax_device *dax_dev) | |
1da177e4 LT |
1807 | { |
1808 | xfs_buftarg_t *btp; | |
1809 | ||
b17cb364 | 1810 | btp = kmem_zalloc(sizeof(*btp), KM_SLEEP | KM_NOFS); |
1da177e4 | 1811 | |
ebad861b | 1812 | btp->bt_mount = mp; |
ce8e922c NS |
1813 | btp->bt_dev = bdev->bd_dev; |
1814 | btp->bt_bdev = bdev; | |
486aff5e | 1815 | btp->bt_daxdev = dax_dev; |
0e6e847f | 1816 | |
1da177e4 | 1817 | if (xfs_setsize_buftarg_early(btp, bdev)) |
d210a987 | 1818 | goto error_free; |
5ca302c8 GC |
1819 | |
1820 | if (list_lru_init(&btp->bt_lru)) | |
d210a987 | 1821 | goto error_free; |
5ca302c8 | 1822 | |
9c7504aa | 1823 | if (percpu_counter_init(&btp->bt_io_count, 0, GFP_KERNEL)) |
d210a987 | 1824 | goto error_lru; |
9c7504aa | 1825 | |
e80dfa19 DC |
1826 | btp->bt_shrinker.count_objects = xfs_buftarg_shrink_count; |
1827 | btp->bt_shrinker.scan_objects = xfs_buftarg_shrink_scan; | |
ff57ab21 | 1828 | btp->bt_shrinker.seeks = DEFAULT_SEEKS; |
e80dfa19 | 1829 | btp->bt_shrinker.flags = SHRINKER_NUMA_AWARE; |
d210a987 MH |
1830 | if (register_shrinker(&btp->bt_shrinker)) |
1831 | goto error_pcpu; | |
1da177e4 LT |
1832 | return btp; |
1833 | ||
d210a987 MH |
1834 | error_pcpu: |
1835 | percpu_counter_destroy(&btp->bt_io_count); | |
1836 | error_lru: | |
1837 | list_lru_destroy(&btp->bt_lru); | |
1838 | error_free: | |
f0e2d93c | 1839 | kmem_free(btp); |
1da177e4 LT |
1840 | return NULL; |
1841 | } | |
1842 | ||
20e8a063 BF |
1843 | /* |
1844 | * Cancel a delayed write list. | |
1845 | * | |
1846 | * Remove each buffer from the list, clear the delwri queue flag and drop the | |
1847 | * associated buffer reference. | |
1848 | */ | |
1849 | void | |
1850 | xfs_buf_delwri_cancel( | |
1851 | struct list_head *list) | |
1852 | { | |
1853 | struct xfs_buf *bp; | |
1854 | ||
1855 | while (!list_empty(list)) { | |
1856 | bp = list_first_entry(list, struct xfs_buf, b_list); | |
1857 | ||
1858 | xfs_buf_lock(bp); | |
1859 | bp->b_flags &= ~_XBF_DELWRI_Q; | |
1860 | list_del_init(&bp->b_list); | |
1861 | xfs_buf_relse(bp); | |
1862 | } | |
1863 | } | |
1864 | ||
1da177e4 | 1865 | /* |
43ff2122 CH |
1866 | * Add a buffer to the delayed write list. |
1867 | * | |
1868 | * This queues a buffer for writeout if it hasn't already been. Note that | |
1869 | * neither this routine nor the buffer list submission functions perform | |
1870 | * any internal synchronization. It is expected that the lists are thread-local | |
1871 | * to the callers. | |
1872 | * | |
1873 | * Returns true if we queued up the buffer, or false if it already had | |
1874 | * been on the buffer list. | |
1da177e4 | 1875 | */ |
43ff2122 | 1876 | bool |
ce8e922c | 1877 | xfs_buf_delwri_queue( |
43ff2122 CH |
1878 | struct xfs_buf *bp, |
1879 | struct list_head *list) | |
1da177e4 | 1880 | { |
43ff2122 | 1881 | ASSERT(xfs_buf_islocked(bp)); |
5a8ee6ba | 1882 | ASSERT(!(bp->b_flags & XBF_READ)); |
1da177e4 | 1883 | |
43ff2122 CH |
1884 | /* |
1885 | * If the buffer is already marked delwri it already is queued up | |
1886 | * by someone else for imediate writeout. Just ignore it in that | |
1887 | * case. | |
1888 | */ | |
1889 | if (bp->b_flags & _XBF_DELWRI_Q) { | |
1890 | trace_xfs_buf_delwri_queued(bp, _RET_IP_); | |
1891 | return false; | |
1da177e4 | 1892 | } |
1da177e4 | 1893 | |
43ff2122 | 1894 | trace_xfs_buf_delwri_queue(bp, _RET_IP_); |
d808f617 DC |
1895 | |
1896 | /* | |
43ff2122 CH |
1897 | * If a buffer gets written out synchronously or marked stale while it |
1898 | * is on a delwri list we lazily remove it. To do this, the other party | |
1899 | * clears the _XBF_DELWRI_Q flag but otherwise leaves the buffer alone. | |
1900 | * It remains referenced and on the list. In a rare corner case it | |
1901 | * might get readded to a delwri list after the synchronous writeout, in | |
1902 | * which case we need just need to re-add the flag here. | |
d808f617 | 1903 | */ |
43ff2122 CH |
1904 | bp->b_flags |= _XBF_DELWRI_Q; |
1905 | if (list_empty(&bp->b_list)) { | |
1906 | atomic_inc(&bp->b_hold); | |
1907 | list_add_tail(&bp->b_list, list); | |
585e6d88 | 1908 | } |
585e6d88 | 1909 | |
43ff2122 | 1910 | return true; |
585e6d88 DC |
1911 | } |
1912 | ||
089716aa DC |
1913 | /* |
1914 | * Compare function is more complex than it needs to be because | |
1915 | * the return value is only 32 bits and we are doing comparisons | |
1916 | * on 64 bit values | |
1917 | */ | |
1918 | static int | |
1919 | xfs_buf_cmp( | |
1920 | void *priv, | |
1921 | struct list_head *a, | |
1922 | struct list_head *b) | |
1923 | { | |
1924 | struct xfs_buf *ap = container_of(a, struct xfs_buf, b_list); | |
1925 | struct xfs_buf *bp = container_of(b, struct xfs_buf, b_list); | |
1926 | xfs_daddr_t diff; | |
1927 | ||
f4b42421 | 1928 | diff = ap->b_maps[0].bm_bn - bp->b_maps[0].bm_bn; |
089716aa DC |
1929 | if (diff < 0) |
1930 | return -1; | |
1931 | if (diff > 0) | |
1932 | return 1; | |
1933 | return 0; | |
1934 | } | |
1935 | ||
26f1fe85 DC |
1936 | /* |
1937 | * submit buffers for write. | |
1938 | * | |
1939 | * When we have a large buffer list, we do not want to hold all the buffers | |
1940 | * locked while we block on the request queue waiting for IO dispatch. To avoid | |
1941 | * this problem, we lock and submit buffers in groups of 50, thereby minimising | |
1942 | * the lock hold times for lists which may contain thousands of objects. | |
1943 | * | |
1944 | * To do this, we sort the buffer list before we walk the list to lock and | |
1945 | * submit buffers, and we plug and unplug around each group of buffers we | |
1946 | * submit. | |
1947 | */ | |
43ff2122 | 1948 | static int |
26f1fe85 | 1949 | xfs_buf_delwri_submit_buffers( |
43ff2122 | 1950 | struct list_head *buffer_list, |
26f1fe85 | 1951 | struct list_head *wait_list) |
1da177e4 | 1952 | { |
43ff2122 | 1953 | struct xfs_buf *bp, *n; |
26f1fe85 | 1954 | LIST_HEAD (submit_list); |
43ff2122 | 1955 | int pinned = 0; |
26f1fe85 | 1956 | struct blk_plug plug; |
43ff2122 | 1957 | |
26f1fe85 | 1958 | list_sort(NULL, buffer_list, xfs_buf_cmp); |
43ff2122 | 1959 | |
26f1fe85 | 1960 | blk_start_plug(&plug); |
43ff2122 | 1961 | list_for_each_entry_safe(bp, n, buffer_list, b_list) { |
26f1fe85 | 1962 | if (!wait_list) { |
43ff2122 CH |
1963 | if (xfs_buf_ispinned(bp)) { |
1964 | pinned++; | |
1965 | continue; | |
1966 | } | |
1967 | if (!xfs_buf_trylock(bp)) | |
1968 | continue; | |
1969 | } else { | |
1970 | xfs_buf_lock(bp); | |
1971 | } | |
978c7b2f | 1972 | |
43ff2122 CH |
1973 | /* |
1974 | * Someone else might have written the buffer synchronously or | |
1975 | * marked it stale in the meantime. In that case only the | |
1976 | * _XBF_DELWRI_Q flag got cleared, and we have to drop the | |
1977 | * reference and remove it from the list here. | |
1978 | */ | |
1979 | if (!(bp->b_flags & _XBF_DELWRI_Q)) { | |
1980 | list_del_init(&bp->b_list); | |
1981 | xfs_buf_relse(bp); | |
1982 | continue; | |
1983 | } | |
c9c12971 | 1984 | |
43ff2122 | 1985 | trace_xfs_buf_delwri_split(bp, _RET_IP_); |
a1b7ea5d | 1986 | |
cf53e99d | 1987 | /* |
26f1fe85 DC |
1988 | * We do all IO submission async. This means if we need |
1989 | * to wait for IO completion we need to take an extra | |
1990 | * reference so the buffer is still valid on the other | |
1991 | * side. We need to move the buffer onto the io_list | |
1992 | * at this point so the caller can still access it. | |
cf53e99d | 1993 | */ |
bbfeb614 | 1994 | bp->b_flags &= ~(_XBF_DELWRI_Q | XBF_WRITE_FAIL); |
26f1fe85 DC |
1995 | bp->b_flags |= XBF_WRITE | XBF_ASYNC; |
1996 | if (wait_list) { | |
cf53e99d | 1997 | xfs_buf_hold(bp); |
26f1fe85 DC |
1998 | list_move_tail(&bp->b_list, wait_list); |
1999 | } else | |
ce8e922c | 2000 | list_del_init(&bp->b_list); |
8dac3921 | 2001 | |
595bff75 | 2002 | xfs_buf_submit(bp); |
43ff2122 CH |
2003 | } |
2004 | blk_finish_plug(&plug); | |
1da177e4 | 2005 | |
43ff2122 | 2006 | return pinned; |
1da177e4 LT |
2007 | } |
2008 | ||
2009 | /* | |
43ff2122 CH |
2010 | * Write out a buffer list asynchronously. |
2011 | * | |
2012 | * This will take the @buffer_list, write all non-locked and non-pinned buffers | |
2013 | * out and not wait for I/O completion on any of the buffers. This interface | |
2014 | * is only safely useable for callers that can track I/O completion by higher | |
2015 | * level means, e.g. AIL pushing as the @buffer_list is consumed in this | |
2016 | * function. | |
1da177e4 LT |
2017 | */ |
2018 | int | |
43ff2122 CH |
2019 | xfs_buf_delwri_submit_nowait( |
2020 | struct list_head *buffer_list) | |
1da177e4 | 2021 | { |
26f1fe85 | 2022 | return xfs_buf_delwri_submit_buffers(buffer_list, NULL); |
43ff2122 | 2023 | } |
1da177e4 | 2024 | |
43ff2122 CH |
2025 | /* |
2026 | * Write out a buffer list synchronously. | |
2027 | * | |
2028 | * This will take the @buffer_list, write all buffers out and wait for I/O | |
2029 | * completion on all of the buffers. @buffer_list is consumed by the function, | |
2030 | * so callers must have some other way of tracking buffers if they require such | |
2031 | * functionality. | |
2032 | */ | |
2033 | int | |
2034 | xfs_buf_delwri_submit( | |
2035 | struct list_head *buffer_list) | |
2036 | { | |
26f1fe85 | 2037 | LIST_HEAD (wait_list); |
43ff2122 CH |
2038 | int error = 0, error2; |
2039 | struct xfs_buf *bp; | |
1da177e4 | 2040 | |
26f1fe85 | 2041 | xfs_buf_delwri_submit_buffers(buffer_list, &wait_list); |
1da177e4 | 2042 | |
43ff2122 | 2043 | /* Wait for IO to complete. */ |
26f1fe85 DC |
2044 | while (!list_empty(&wait_list)) { |
2045 | bp = list_first_entry(&wait_list, struct xfs_buf, b_list); | |
a1b7ea5d | 2046 | |
089716aa | 2047 | list_del_init(&bp->b_list); |
cf53e99d DC |
2048 | |
2049 | /* locking the buffer will wait for async IO completion. */ | |
2050 | xfs_buf_lock(bp); | |
2051 | error2 = bp->b_error; | |
43ff2122 CH |
2052 | xfs_buf_relse(bp); |
2053 | if (!error) | |
2054 | error = error2; | |
1da177e4 LT |
2055 | } |
2056 | ||
43ff2122 | 2057 | return error; |
1da177e4 LT |
2058 | } |
2059 | ||
7912e7fe BF |
2060 | /* |
2061 | * Push a single buffer on a delwri queue. | |
2062 | * | |
2063 | * The purpose of this function is to submit a single buffer of a delwri queue | |
2064 | * and return with the buffer still on the original queue. The waiting delwri | |
2065 | * buffer submission infrastructure guarantees transfer of the delwri queue | |
2066 | * buffer reference to a temporary wait list. We reuse this infrastructure to | |
2067 | * transfer the buffer back to the original queue. | |
2068 | * | |
2069 | * Note the buffer transitions from the queued state, to the submitted and wait | |
2070 | * listed state and back to the queued state during this call. The buffer | |
2071 | * locking and queue management logic between _delwri_pushbuf() and | |
2072 | * _delwri_queue() guarantee that the buffer cannot be queued to another list | |
2073 | * before returning. | |
2074 | */ | |
2075 | int | |
2076 | xfs_buf_delwri_pushbuf( | |
2077 | struct xfs_buf *bp, | |
2078 | struct list_head *buffer_list) | |
2079 | { | |
2080 | LIST_HEAD (submit_list); | |
2081 | int error; | |
2082 | ||
2083 | ASSERT(bp->b_flags & _XBF_DELWRI_Q); | |
2084 | ||
2085 | trace_xfs_buf_delwri_pushbuf(bp, _RET_IP_); | |
2086 | ||
2087 | /* | |
2088 | * Isolate the buffer to a new local list so we can submit it for I/O | |
2089 | * independently from the rest of the original list. | |
2090 | */ | |
2091 | xfs_buf_lock(bp); | |
2092 | list_move(&bp->b_list, &submit_list); | |
2093 | xfs_buf_unlock(bp); | |
2094 | ||
2095 | /* | |
2096 | * Delwri submission clears the DELWRI_Q buffer flag and returns with | |
2097 | * the buffer on the wait list with an associated reference. Rather than | |
2098 | * bounce the buffer from a local wait list back to the original list | |
2099 | * after I/O completion, reuse the original list as the wait list. | |
2100 | */ | |
2101 | xfs_buf_delwri_submit_buffers(&submit_list, buffer_list); | |
2102 | ||
2103 | /* | |
2104 | * The buffer is now under I/O and wait listed as during typical delwri | |
2105 | * submission. Lock the buffer to wait for I/O completion. Rather than | |
2106 | * remove the buffer from the wait list and release the reference, we | |
2107 | * want to return with the buffer queued to the original list. The | |
2108 | * buffer already sits on the original list with a wait list reference, | |
2109 | * however. If we let the queue inherit that wait list reference, all we | |
2110 | * need to do is reset the DELWRI_Q flag. | |
2111 | */ | |
2112 | xfs_buf_lock(bp); | |
2113 | error = bp->b_error; | |
2114 | bp->b_flags |= _XBF_DELWRI_Q; | |
2115 | xfs_buf_unlock(bp); | |
2116 | ||
2117 | return error; | |
2118 | } | |
2119 | ||
04d8b284 | 2120 | int __init |
ce8e922c | 2121 | xfs_buf_init(void) |
1da177e4 | 2122 | { |
8758280f NS |
2123 | xfs_buf_zone = kmem_zone_init_flags(sizeof(xfs_buf_t), "xfs_buf", |
2124 | KM_ZONE_HWALIGN, NULL); | |
ce8e922c | 2125 | if (!xfs_buf_zone) |
0b1b213f | 2126 | goto out; |
04d8b284 | 2127 | |
23ea4032 | 2128 | return 0; |
1da177e4 | 2129 | |
0b1b213f | 2130 | out: |
8758280f | 2131 | return -ENOMEM; |
1da177e4 LT |
2132 | } |
2133 | ||
1da177e4 | 2134 | void |
ce8e922c | 2135 | xfs_buf_terminate(void) |
1da177e4 | 2136 | { |
ce8e922c | 2137 | kmem_zone_destroy(xfs_buf_zone); |
1da177e4 | 2138 | } |
7561d27e BF |
2139 | |
2140 | void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) | |
2141 | { | |
7561d27e BF |
2142 | /* |
2143 | * Set the lru reference count to 0 based on the error injection tag. | |
2144 | * This allows userspace to disrupt buffer caching for debug/testing | |
2145 | * purposes. | |
2146 | */ | |
4eadcf9a BF |
2147 | if (XFS_TEST_ERROR(false, bp->b_target->bt_mount, |
2148 | XFS_ERRTAG_BUF_LRU_REF)) | |
7561d27e BF |
2149 | lru_ref = 0; |
2150 | ||
2151 | atomic_set(&bp->b_lru_ref, lru_ref); | |
2152 | } |