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7336d0e6 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
b3b94faa DT |
2 | /* |
3 | * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. | |
091806ed | 4 | * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. |
b3b94faa DT |
5 | */ |
6 | ||
7 | #include <linux/sched.h> | |
8 | #include <linux/slab.h> | |
9 | #include <linux/spinlock.h> | |
10 | #include <linux/completion.h> | |
11 | #include <linux/buffer_head.h> | |
12 | #include <linux/mm.h> | |
13 | #include <linux/pagemap.h> | |
14 | #include <linux/writeback.h> | |
15 | #include <linux/swap.h> | |
16 | #include <linux/delay.h> | |
2e565bb6 | 17 | #include <linux/bio.h> |
5c676f6d | 18 | #include <linux/gfs2_ondisk.h> |
b3b94faa DT |
19 | |
20 | #include "gfs2.h" | |
5c676f6d | 21 | #include "incore.h" |
b3b94faa DT |
22 | #include "glock.h" |
23 | #include "glops.h" | |
24 | #include "inode.h" | |
25 | #include "log.h" | |
26 | #include "lops.h" | |
27 | #include "meta_io.h" | |
28 | #include "rgrp.h" | |
29 | #include "trans.h" | |
5c676f6d | 30 | #include "util.h" |
627c10b7 | 31 | #include "trace_gfs2.h" |
b3b94faa | 32 | |
4a0f9a32 | 33 | static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wbc) |
b3b94faa | 34 | { |
4a0f9a32 SW |
35 | struct buffer_head *bh, *head; |
36 | int nr_underway = 0; | |
67688c08 | 37 | blk_opf_t write_flags = REQ_META | REQ_PRIO | wbc_to_write_flags(wbc); |
b3b94faa | 38 | |
4a0f9a32 SW |
39 | BUG_ON(!PageLocked(page)); |
40 | BUG_ON(!page_has_buffers(page)); | |
41 | ||
42 | head = page_buffers(page); | |
43 | bh = head; | |
44 | ||
45 | do { | |
46 | if (!buffer_mapped(bh)) | |
47 | continue; | |
48 | /* | |
49 | * If it's a fully non-blocking write attempt and we cannot | |
50 | * lock the buffer then redirty the page. Note that this can | |
e76e0ec9 | 51 | * potentially cause a busy-wait loop from flusher thread and kswapd |
4a0f9a32 SW |
52 | * activity, but those code paths have their own higher-level |
53 | * throttling. | |
54 | */ | |
1b430bee | 55 | if (wbc->sync_mode != WB_SYNC_NONE) { |
4a0f9a32 SW |
56 | lock_buffer(bh); |
57 | } else if (!trylock_buffer(bh)) { | |
58 | redirty_page_for_writepage(wbc, page); | |
59 | continue; | |
60 | } | |
61 | if (test_clear_buffer_dirty(bh)) { | |
62 | mark_buffer_async_write(bh); | |
63 | } else { | |
64 | unlock_buffer(bh); | |
65 | } | |
66 | } while ((bh = bh->b_this_page) != head); | |
67 | ||
68 | /* | |
69 | * The page and its buffers are protected by PageWriteback(), so we can | |
70 | * drop the bh refcounts early. | |
71 | */ | |
72 | BUG_ON(PageWriteback(page)); | |
73 | set_page_writeback(page); | |
74 | ||
75 | do { | |
76 | struct buffer_head *next = bh->b_this_page; | |
77 | if (buffer_async_write(bh)) { | |
1420c4a5 | 78 | submit_bh(REQ_OP_WRITE | write_flags, bh); |
4a0f9a32 SW |
79 | nr_underway++; |
80 | } | |
81 | bh = next; | |
82 | } while (bh != head); | |
83 | unlock_page(page); | |
84 | ||
4a0f9a32 SW |
85 | if (nr_underway == 0) |
86 | end_page_writeback(page); | |
87 | ||
eaefbf96 | 88 | return 0; |
b3b94faa DT |
89 | } |
90 | ||
009d8518 | 91 | const struct address_space_operations gfs2_meta_aops = { |
e621900a | 92 | .dirty_folio = block_dirty_folio, |
7ba13abb | 93 | .invalidate_folio = block_invalidate_folio, |
b3b94faa | 94 | .writepage = gfs2_aspace_writepage, |
e45c20d1 | 95 | .release_folio = gfs2_release_folio, |
b3b94faa DT |
96 | }; |
97 | ||
1b2ad412 | 98 | const struct address_space_operations gfs2_rgrp_aops = { |
e621900a | 99 | .dirty_folio = block_dirty_folio, |
7ba13abb | 100 | .invalidate_folio = block_invalidate_folio, |
1b2ad412 | 101 | .writepage = gfs2_aspace_writepage, |
e45c20d1 | 102 | .release_folio = gfs2_release_folio, |
1b2ad412 SW |
103 | }; |
104 | ||
b3b94faa | 105 | /** |
6802e340 | 106 | * gfs2_getbuf - Get a buffer with a given address space |
cb4c0313 | 107 | * @gl: the glock |
b3b94faa DT |
108 | * @blkno: the block number (filesystem scope) |
109 | * @create: 1 if the buffer should be created | |
110 | * | |
111 | * Returns: the buffer | |
112 | */ | |
113 | ||
6802e340 | 114 | struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create) |
b3b94faa | 115 | { |
009d8518 | 116 | struct address_space *mapping = gfs2_glock2aspace(gl); |
15562c43 | 117 | struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; |
b3b94faa DT |
118 | struct page *page; |
119 | struct buffer_head *bh; | |
120 | unsigned int shift; | |
121 | unsigned long index; | |
122 | unsigned int bufnum; | |
123 | ||
70d4ee94 SW |
124 | if (mapping == NULL) |
125 | mapping = &sdp->sd_aspace; | |
126 | ||
09cbfeaf | 127 | shift = PAGE_SHIFT - sdp->sd_sb.sb_bsize_shift; |
b3b94faa DT |
128 | index = blkno >> shift; /* convert block to page */ |
129 | bufnum = blkno - (index << shift); /* block buf index within page */ | |
130 | ||
131 | if (create) { | |
132 | for (;;) { | |
cb4c0313 | 133 | page = grab_cache_page(mapping, index); |
b3b94faa DT |
134 | if (page) |
135 | break; | |
136 | yield(); | |
137 | } | |
e7dfab82 BP |
138 | if (!page_has_buffers(page)) |
139 | create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0); | |
b3b94faa | 140 | } else { |
2457aec6 MG |
141 | page = find_get_page_flags(mapping, index, |
142 | FGP_LOCK|FGP_ACCESSED); | |
b3b94faa DT |
143 | if (!page) |
144 | return NULL; | |
e7dfab82 BP |
145 | if (!page_has_buffers(page)) { |
146 | bh = NULL; | |
147 | goto out_unlock; | |
148 | } | |
b3b94faa DT |
149 | } |
150 | ||
b3b94faa DT |
151 | /* Locate header for our buffer within our page */ |
152 | for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page) | |
153 | /* Do nothing */; | |
154 | get_bh(bh); | |
155 | ||
156 | if (!buffer_mapped(bh)) | |
157 | map_bh(bh, sdp->sd_vfs, blkno); | |
158 | ||
e7dfab82 | 159 | out_unlock: |
b3b94faa | 160 | unlock_page(page); |
09cbfeaf | 161 | put_page(page); |
b3b94faa DT |
162 | |
163 | return bh; | |
164 | } | |
165 | ||
166 | static void meta_prep_new(struct buffer_head *bh) | |
167 | { | |
168 | struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data; | |
169 | ||
170 | lock_buffer(bh); | |
171 | clear_buffer_dirty(bh); | |
172 | set_buffer_uptodate(bh); | |
173 | unlock_buffer(bh); | |
174 | ||
175 | mh->mh_magic = cpu_to_be32(GFS2_MAGIC); | |
176 | } | |
177 | ||
178 | /** | |
179 | * gfs2_meta_new - Get a block | |
180 | * @gl: The glock associated with this block | |
181 | * @blkno: The block number | |
182 | * | |
183 | * Returns: The buffer | |
184 | */ | |
185 | ||
cd915493 | 186 | struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno) |
b3b94faa DT |
187 | { |
188 | struct buffer_head *bh; | |
6802e340 | 189 | bh = gfs2_getbuf(gl, blkno, CREATE); |
b3b94faa DT |
190 | meta_prep_new(bh); |
191 | return bh; | |
192 | } | |
193 | ||
39b0555f | 194 | static void gfs2_meta_read_endio(struct bio *bio) |
c8d57703 | 195 | { |
39b0555f | 196 | struct bio_vec *bvec; |
6dc4f100 | 197 | struct bvec_iter_all iter_all; |
39b0555f | 198 | |
2b070cfe | 199 | bio_for_each_segment_all(bvec, bio, iter_all) { |
39b0555f AG |
200 | struct page *page = bvec->bv_page; |
201 | struct buffer_head *bh = page_buffers(page); | |
202 | unsigned int len = bvec->bv_len; | |
203 | ||
204 | while (bh_offset(bh) < bvec->bv_offset) | |
205 | bh = bh->b_this_page; | |
206 | do { | |
207 | struct buffer_head *next = bh->b_this_page; | |
208 | len -= bh->b_size; | |
4e4cbee9 | 209 | bh->b_end_io(bh, !bio->bi_status); |
39b0555f AG |
210 | bh = next; |
211 | } while (bh && len); | |
212 | } | |
213 | bio_put(bio); | |
214 | } | |
c8d57703 | 215 | |
39b0555f AG |
216 | /* |
217 | * Submit several consecutive buffer head I/O requests as a single bio I/O | |
218 | * request. (See submit_bh_wbc.) | |
219 | */ | |
67688c08 | 220 | static void gfs2_submit_bhs(blk_opf_t opf, struct buffer_head *bhs[], int num) |
39b0555f | 221 | { |
23e5671a AG |
222 | while (num > 0) { |
223 | struct buffer_head *bh = *bhs; | |
224 | struct bio *bio; | |
225 | ||
67688c08 | 226 | bio = bio_alloc(bh->b_bdev, num, opf, GFP_NOIO); |
23e5671a | 227 | bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); |
23e5671a AG |
228 | while (num > 0) { |
229 | bh = *bhs; | |
230 | if (!bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh))) { | |
231 | BUG_ON(bio->bi_iter.bi_size == 0); | |
232 | break; | |
233 | } | |
234 | bhs++; | |
235 | num--; | |
236 | } | |
237 | bio->bi_end_io = gfs2_meta_read_endio; | |
23e5671a | 238 | submit_bio(bio); |
c8d57703 | 239 | } |
c8d57703 AG |
240 | } |
241 | ||
b3b94faa DT |
242 | /** |
243 | * gfs2_meta_read - Read a block from disk | |
244 | * @gl: The glock covering the block | |
245 | * @blkno: The block number | |
7276b3b0 | 246 | * @flags: flags |
c551f66c | 247 | * @rahead: Do read-ahead |
b3b94faa DT |
248 | * @bhp: the place where the buffer is returned (NULL on failure) |
249 | * | |
250 | * Returns: errno | |
251 | */ | |
252 | ||
cd915493 | 253 | int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags, |
c8d57703 | 254 | int rahead, struct buffer_head **bhp) |
b3b94faa | 255 | { |
15562c43 | 256 | struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; |
39b0555f AG |
257 | struct buffer_head *bh, *bhs[2]; |
258 | int num = 0; | |
c969f58c | 259 | |
8cc67f70 | 260 | if (unlikely(gfs2_withdrawn(sdp)) && !gfs2_withdraw_in_prog(sdp)) { |
44b8db13 | 261 | *bhp = NULL; |
c969f58c | 262 | return -EIO; |
44b8db13 | 263 | } |
c969f58c SW |
264 | |
265 | *bhp = bh = gfs2_getbuf(gl, blkno, CREATE); | |
266 | ||
267 | lock_buffer(bh); | |
268 | if (buffer_uptodate(bh)) { | |
269 | unlock_buffer(bh); | |
39b0555f AG |
270 | flags &= ~DIO_WAIT; |
271 | } else { | |
272 | bh->b_end_io = end_buffer_read_sync; | |
273 | get_bh(bh); | |
274 | bhs[num++] = bh; | |
c969f58c | 275 | } |
39b0555f AG |
276 | |
277 | if (rahead) { | |
278 | bh = gfs2_getbuf(gl, blkno + 1, CREATE); | |
279 | ||
280 | lock_buffer(bh); | |
281 | if (buffer_uptodate(bh)) { | |
282 | unlock_buffer(bh); | |
283 | brelse(bh); | |
284 | } else { | |
285 | bh->b_end_io = end_buffer_read_sync; | |
286 | bhs[num++] = bh; | |
287 | } | |
288 | } | |
289 | ||
67688c08 | 290 | gfs2_submit_bhs(REQ_OP_READ | REQ_META | REQ_PRIO, bhs, num); |
c969f58c SW |
291 | if (!(flags & DIO_WAIT)) |
292 | return 0; | |
293 | ||
39b0555f | 294 | bh = *bhp; |
c969f58c SW |
295 | wait_on_buffer(bh); |
296 | if (unlikely(!buffer_uptodate(bh))) { | |
297 | struct gfs2_trans *tr = current->journal_info; | |
9862ca05 | 298 | if (tr && test_bit(TR_TOUCHED, &tr->tr_flags)) |
9e1a9ecd | 299 | gfs2_io_error_bh_wd(sdp, bh); |
c969f58c | 300 | brelse(bh); |
44b8db13 | 301 | *bhp = NULL; |
c969f58c | 302 | return -EIO; |
7276b3b0 | 303 | } |
b3b94faa | 304 | |
7276b3b0 | 305 | return 0; |
b3b94faa DT |
306 | } |
307 | ||
308 | /** | |
7276b3b0 | 309 | * gfs2_meta_wait - Reread a block from disk |
b3b94faa | 310 | * @sdp: the filesystem |
7276b3b0 | 311 | * @bh: The block to wait for |
b3b94faa DT |
312 | * |
313 | * Returns: errno | |
314 | */ | |
315 | ||
7276b3b0 | 316 | int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh) |
b3b94faa | 317 | { |
8cc67f70 | 318 | if (unlikely(gfs2_withdrawn(sdp)) && !gfs2_withdraw_in_prog(sdp)) |
b3b94faa DT |
319 | return -EIO; |
320 | ||
7276b3b0 | 321 | wait_on_buffer(bh); |
b3b94faa | 322 | |
7276b3b0 SW |
323 | if (!buffer_uptodate(bh)) { |
324 | struct gfs2_trans *tr = current->journal_info; | |
9862ca05 | 325 | if (tr && test_bit(TR_TOUCHED, &tr->tr_flags)) |
9e1a9ecd | 326 | gfs2_io_error_bh_wd(sdp, bh); |
7276b3b0 | 327 | return -EIO; |
b3b94faa | 328 | } |
8cc67f70 | 329 | if (unlikely(gfs2_withdrawn(sdp)) && !gfs2_withdraw_in_prog(sdp)) |
7276b3b0 | 330 | return -EIO; |
b3b94faa DT |
331 | |
332 | return 0; | |
333 | } | |
334 | ||
68cd4ce2 | 335 | void gfs2_remove_from_journal(struct buffer_head *bh, int meta) |
16615be1 | 336 | { |
009d8518 SW |
337 | struct address_space *mapping = bh->b_page->mapping; |
338 | struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping); | |
16615be1 | 339 | struct gfs2_bufdata *bd = bh->b_private; |
68cd4ce2 | 340 | struct gfs2_trans *tr = current->journal_info; |
502be2a3 | 341 | int was_pinned = 0; |
009d8518 | 342 | |
16615be1 | 343 | if (test_clear_buffer_pinned(bh)) { |
627c10b7 | 344 | trace_gfs2_pin(bd, 0); |
5e687eac | 345 | atomic_dec(&sdp->sd_log_pinned); |
c0752aa7 | 346 | list_del_init(&bd->bd_list); |
68cd4ce2 | 347 | if (meta == REMOVE_META) |
16615be1 | 348 | tr->tr_num_buf_rm++; |
022ef4fe | 349 | else |
16615be1 | 350 | tr->tr_num_databuf_rm++; |
9862ca05 | 351 | set_bit(TR_TOUCHED, &tr->tr_flags); |
502be2a3 | 352 | was_pinned = 1; |
16615be1 SW |
353 | brelse(bh); |
354 | } | |
355 | if (bd) { | |
16ca9412 | 356 | if (bd->bd_tr) { |
16615be1 | 357 | gfs2_trans_add_revoke(sdp, bd); |
502be2a3 BP |
358 | } else if (was_pinned) { |
359 | bh->b_private = NULL; | |
360 | kmem_cache_free(gfs2_bufdata_cachep, bd); | |
68942870 BP |
361 | } else if (!list_empty(&bd->bd_ail_st_list) && |
362 | !list_empty(&bd->bd_ail_gl_list)) { | |
363 | gfs2_remove_from_ail(bd); | |
16615be1 SW |
364 | } |
365 | } | |
366 | clear_buffer_dirty(bh); | |
367 | clear_buffer_uptodate(bh); | |
368 | } | |
369 | ||
b3b94faa | 370 | /** |
68942870 BP |
371 | * gfs2_ail1_wipe - remove deleted/freed buffers from the ail1 list |
372 | * @sdp: superblock | |
373 | * @bstart: starting block address of buffers to remove | |
374 | * @blen: length of buffers to be removed | |
375 | * | |
376 | * This function is called from gfs2_journal wipe, whose job is to remove | |
377 | * buffers, corresponding to deleted blocks, from the journal. If we find any | |
378 | * bufdata elements on the system ail1 list, they haven't been written to | |
379 | * the journal yet. So we remove them. | |
380 | */ | |
381 | static void gfs2_ail1_wipe(struct gfs2_sbd *sdp, u64 bstart, u32 blen) | |
382 | { | |
383 | struct gfs2_trans *tr, *s; | |
384 | struct gfs2_bufdata *bd, *bs; | |
385 | struct buffer_head *bh; | |
386 | u64 end = bstart + blen; | |
387 | ||
388 | gfs2_log_lock(sdp); | |
389 | spin_lock(&sdp->sd_ail_lock); | |
390 | list_for_each_entry_safe(tr, s, &sdp->sd_ail1_list, tr_list) { | |
391 | list_for_each_entry_safe(bd, bs, &tr->tr_ail1_list, | |
392 | bd_ail_st_list) { | |
393 | bh = bd->bd_bh; | |
394 | if (bh->b_blocknr < bstart || bh->b_blocknr >= end) | |
395 | continue; | |
396 | ||
397 | gfs2_remove_from_journal(bh, REMOVE_JDATA); | |
398 | } | |
399 | } | |
400 | spin_unlock(&sdp->sd_ail_lock); | |
401 | gfs2_log_unlock(sdp); | |
402 | } | |
403 | ||
404 | static struct buffer_head *gfs2_getjdatabuf(struct gfs2_inode *ip, u64 blkno) | |
405 | { | |
406 | struct address_space *mapping = ip->i_inode.i_mapping; | |
407 | struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); | |
408 | struct page *page; | |
409 | struct buffer_head *bh; | |
410 | unsigned int shift = PAGE_SHIFT - sdp->sd_sb.sb_bsize_shift; | |
411 | unsigned long index = blkno >> shift; /* convert block to page */ | |
412 | unsigned int bufnum = blkno - (index << shift); | |
413 | ||
414 | page = find_get_page_flags(mapping, index, FGP_LOCK|FGP_ACCESSED); | |
415 | if (!page) | |
416 | return NULL; | |
417 | if (!page_has_buffers(page)) { | |
418 | unlock_page(page); | |
419 | put_page(page); | |
420 | return NULL; | |
421 | } | |
422 | /* Locate header for our buffer within our page */ | |
423 | for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page) | |
424 | /* Do nothing */; | |
425 | get_bh(bh); | |
426 | unlock_page(page); | |
427 | put_page(page); | |
428 | return bh; | |
429 | } | |
430 | ||
431 | /** | |
432 | * gfs2_journal_wipe - make inode's buffers so they aren't dirty/pinned anymore | |
b3b94faa DT |
433 | * @ip: the inode who owns the buffers |
434 | * @bstart: the first buffer in the run | |
435 | * @blen: the number of buffers in the run | |
436 | * | |
437 | */ | |
438 | ||
68942870 | 439 | void gfs2_journal_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen) |
b3b94faa | 440 | { |
feaa7bba | 441 | struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); |
b3b94faa | 442 | struct buffer_head *bh; |
68942870 | 443 | int ty; |
b3b94faa | 444 | |
68942870 | 445 | gfs2_ail1_wipe(sdp, bstart, blen); |
b3b94faa | 446 | while (blen) { |
68942870 | 447 | ty = REMOVE_META; |
6802e340 | 448 | bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE); |
68942870 BP |
449 | if (!bh && gfs2_is_jdata(ip)) { |
450 | bh = gfs2_getjdatabuf(ip, bstart); | |
451 | ty = REMOVE_JDATA; | |
452 | } | |
b3b94faa | 453 | if (bh) { |
1ad38c43 SW |
454 | lock_buffer(bh); |
455 | gfs2_log_lock(sdp); | |
68942870 BP |
456 | spin_lock(&sdp->sd_ail_lock); |
457 | gfs2_remove_from_journal(bh, ty); | |
458 | spin_unlock(&sdp->sd_ail_lock); | |
1ad38c43 | 459 | gfs2_log_unlock(sdp); |
b3b94faa | 460 | unlock_buffer(bh); |
b3b94faa DT |
461 | brelse(bh); |
462 | } | |
463 | ||
464 | bstart++; | |
465 | blen--; | |
466 | } | |
467 | } | |
468 | ||
b3b94faa | 469 | /** |
6d8da302 | 470 | * gfs2_meta_buffer - Get a metadata buffer |
b3b94faa | 471 | * @ip: The GFS2 inode |
6d8da302 | 472 | * @mtype: The block type (GFS2_METATYPE_*) |
b3b94faa | 473 | * @num: The block number (device relative) of the buffer |
b3b94faa DT |
474 | * @bhp: the buffer is returned here |
475 | * | |
b3b94faa DT |
476 | * Returns: errno |
477 | */ | |
478 | ||
6d8da302 AG |
479 | int gfs2_meta_buffer(struct gfs2_inode *ip, u32 mtype, u64 num, |
480 | struct buffer_head **bhp) | |
b3b94faa | 481 | { |
7276b3b0 SW |
482 | struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); |
483 | struct gfs2_glock *gl = ip->i_gl; | |
f91a0d3e SW |
484 | struct buffer_head *bh; |
485 | int ret = 0; | |
c8d57703 AG |
486 | int rahead = 0; |
487 | ||
488 | if (num == ip->i_no_addr) | |
489 | rahead = ip->i_rahead; | |
b3b94faa | 490 | |
c8d57703 | 491 | ret = gfs2_meta_read(gl, num, DIO_WAIT, rahead, &bh); |
f2f9c812 BP |
492 | if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) { |
493 | brelse(bh); | |
494 | ret = -EIO; | |
61eaadcd BP |
495 | } else { |
496 | *bhp = bh; | |
b3b94faa | 497 | } |
f91a0d3e | 498 | return ret; |
b3b94faa DT |
499 | } |
500 | ||
501 | /** | |
502 | * gfs2_meta_ra - start readahead on an extent of a file | |
503 | * @gl: the glock the blocks belong to | |
504 | * @dblock: the starting disk block | |
505 | * @extlen: the number of blocks in the extent | |
506 | * | |
7276b3b0 | 507 | * returns: the first buffer in the extent |
b3b94faa DT |
508 | */ |
509 | ||
7276b3b0 | 510 | struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen) |
b3b94faa | 511 | { |
15562c43 | 512 | struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; |
b3b94faa | 513 | struct buffer_head *first_bh, *bh; |
cd915493 | 514 | u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >> |
568f4c96 | 515 | sdp->sd_sb.sb_bsize_shift; |
b3b94faa | 516 | |
7276b3b0 SW |
517 | BUG_ON(!extlen); |
518 | ||
519 | if (max_ra < 1) | |
520 | max_ra = 1; | |
b3b94faa DT |
521 | if (extlen > max_ra) |
522 | extlen = max_ra; | |
523 | ||
6802e340 | 524 | first_bh = gfs2_getbuf(gl, dblock, CREATE); |
b3b94faa DT |
525 | |
526 | if (buffer_uptodate(first_bh)) | |
527 | goto out; | |
7276b3b0 | 528 | if (!buffer_locked(first_bh)) |
1420c4a5 | 529 | ll_rw_block(REQ_OP_READ | REQ_META | REQ_PRIO, 1, &first_bh); |
b3b94faa DT |
530 | |
531 | dblock++; | |
532 | extlen--; | |
533 | ||
534 | while (extlen) { | |
6802e340 | 535 | bh = gfs2_getbuf(gl, dblock, CREATE); |
b3b94faa | 536 | |
7276b3b0 | 537 | if (!buffer_uptodate(bh) && !buffer_locked(bh)) |
1420c4a5 BVA |
538 | ll_rw_block(REQ_OP_READ | REQ_RAHEAD | REQ_META | |
539 | REQ_PRIO, 1, &bh); | |
7276b3b0 | 540 | brelse(bh); |
b3b94faa DT |
541 | dblock++; |
542 | extlen--; | |
7276b3b0 SW |
543 | if (!buffer_locked(first_bh) && buffer_uptodate(first_bh)) |
544 | goto out; | |
b3b94faa DT |
545 | } |
546 | ||
7276b3b0 | 547 | wait_on_buffer(first_bh); |
a91ea69f | 548 | out: |
7276b3b0 | 549 | return first_bh; |
b3b94faa DT |
550 | } |
551 |