Commit | Line | Data |
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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; | |
7637241e | 37 | int 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)) { | |
2a222ca9 | 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 = { |
b3b94faa | 92 | .writepage = gfs2_aspace_writepage, |
4340fe62 | 93 | .releasepage = gfs2_releasepage, |
b3b94faa DT |
94 | }; |
95 | ||
1b2ad412 SW |
96 | const struct address_space_operations gfs2_rgrp_aops = { |
97 | .writepage = gfs2_aspace_writepage, | |
98 | .releasepage = gfs2_releasepage, | |
99 | }; | |
100 | ||
b3b94faa | 101 | /** |
6802e340 | 102 | * gfs2_getbuf - Get a buffer with a given address space |
cb4c0313 | 103 | * @gl: the glock |
b3b94faa DT |
104 | * @blkno: the block number (filesystem scope) |
105 | * @create: 1 if the buffer should be created | |
106 | * | |
107 | * Returns: the buffer | |
108 | */ | |
109 | ||
6802e340 | 110 | struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create) |
b3b94faa | 111 | { |
009d8518 | 112 | struct address_space *mapping = gfs2_glock2aspace(gl); |
15562c43 | 113 | struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; |
b3b94faa DT |
114 | struct page *page; |
115 | struct buffer_head *bh; | |
116 | unsigned int shift; | |
117 | unsigned long index; | |
118 | unsigned int bufnum; | |
119 | ||
70d4ee94 SW |
120 | if (mapping == NULL) |
121 | mapping = &sdp->sd_aspace; | |
122 | ||
09cbfeaf | 123 | shift = PAGE_SHIFT - sdp->sd_sb.sb_bsize_shift; |
b3b94faa DT |
124 | index = blkno >> shift; /* convert block to page */ |
125 | bufnum = blkno - (index << shift); /* block buf index within page */ | |
126 | ||
127 | if (create) { | |
128 | for (;;) { | |
cb4c0313 | 129 | page = grab_cache_page(mapping, index); |
b3b94faa DT |
130 | if (page) |
131 | break; | |
132 | yield(); | |
133 | } | |
134 | } else { | |
2457aec6 MG |
135 | page = find_get_page_flags(mapping, index, |
136 | FGP_LOCK|FGP_ACCESSED); | |
b3b94faa DT |
137 | if (!page) |
138 | return NULL; | |
139 | } | |
140 | ||
141 | if (!page_has_buffers(page)) | |
142 | create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0); | |
143 | ||
144 | /* Locate header for our buffer within our page */ | |
145 | for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page) | |
146 | /* Do nothing */; | |
147 | get_bh(bh); | |
148 | ||
149 | if (!buffer_mapped(bh)) | |
150 | map_bh(bh, sdp->sd_vfs, blkno); | |
151 | ||
152 | unlock_page(page); | |
09cbfeaf | 153 | put_page(page); |
b3b94faa DT |
154 | |
155 | return bh; | |
156 | } | |
157 | ||
158 | static void meta_prep_new(struct buffer_head *bh) | |
159 | { | |
160 | struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data; | |
161 | ||
162 | lock_buffer(bh); | |
163 | clear_buffer_dirty(bh); | |
164 | set_buffer_uptodate(bh); | |
165 | unlock_buffer(bh); | |
166 | ||
167 | mh->mh_magic = cpu_to_be32(GFS2_MAGIC); | |
168 | } | |
169 | ||
170 | /** | |
171 | * gfs2_meta_new - Get a block | |
172 | * @gl: The glock associated with this block | |
173 | * @blkno: The block number | |
174 | * | |
175 | * Returns: The buffer | |
176 | */ | |
177 | ||
cd915493 | 178 | struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno) |
b3b94faa DT |
179 | { |
180 | struct buffer_head *bh; | |
6802e340 | 181 | bh = gfs2_getbuf(gl, blkno, CREATE); |
b3b94faa DT |
182 | meta_prep_new(bh); |
183 | return bh; | |
184 | } | |
185 | ||
39b0555f | 186 | static void gfs2_meta_read_endio(struct bio *bio) |
c8d57703 | 187 | { |
39b0555f | 188 | struct bio_vec *bvec; |
6dc4f100 | 189 | struct bvec_iter_all iter_all; |
39b0555f | 190 | |
2b070cfe | 191 | bio_for_each_segment_all(bvec, bio, iter_all) { |
39b0555f AG |
192 | struct page *page = bvec->bv_page; |
193 | struct buffer_head *bh = page_buffers(page); | |
194 | unsigned int len = bvec->bv_len; | |
195 | ||
196 | while (bh_offset(bh) < bvec->bv_offset) | |
197 | bh = bh->b_this_page; | |
198 | do { | |
199 | struct buffer_head *next = bh->b_this_page; | |
200 | len -= bh->b_size; | |
4e4cbee9 | 201 | bh->b_end_io(bh, !bio->bi_status); |
39b0555f AG |
202 | bh = next; |
203 | } while (bh && len); | |
204 | } | |
205 | bio_put(bio); | |
206 | } | |
c8d57703 | 207 | |
39b0555f AG |
208 | /* |
209 | * Submit several consecutive buffer head I/O requests as a single bio I/O | |
210 | * request. (See submit_bh_wbc.) | |
211 | */ | |
e1b1afa6 MC |
212 | static void gfs2_submit_bhs(int op, int op_flags, struct buffer_head *bhs[], |
213 | int num) | |
39b0555f | 214 | { |
23e5671a AG |
215 | while (num > 0) { |
216 | struct buffer_head *bh = *bhs; | |
217 | struct bio *bio; | |
218 | ||
219 | bio = bio_alloc(GFP_NOIO, num); | |
220 | bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); | |
74d46992 | 221 | bio_set_dev(bio, bh->b_bdev); |
23e5671a AG |
222 | while (num > 0) { |
223 | bh = *bhs; | |
224 | if (!bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh))) { | |
225 | BUG_ON(bio->bi_iter.bi_size == 0); | |
226 | break; | |
227 | } | |
228 | bhs++; | |
229 | num--; | |
230 | } | |
231 | bio->bi_end_io = gfs2_meta_read_endio; | |
232 | bio_set_op_attrs(bio, op, op_flags); | |
233 | submit_bio(bio); | |
c8d57703 | 234 | } |
c8d57703 AG |
235 | } |
236 | ||
b3b94faa DT |
237 | /** |
238 | * gfs2_meta_read - Read a block from disk | |
239 | * @gl: The glock covering the block | |
240 | * @blkno: The block number | |
7276b3b0 | 241 | * @flags: flags |
b3b94faa DT |
242 | * @bhp: the place where the buffer is returned (NULL on failure) |
243 | * | |
244 | * Returns: errno | |
245 | */ | |
246 | ||
cd915493 | 247 | int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags, |
c8d57703 | 248 | int rahead, struct buffer_head **bhp) |
b3b94faa | 249 | { |
15562c43 | 250 | struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; |
39b0555f AG |
251 | struct buffer_head *bh, *bhs[2]; |
252 | int num = 0; | |
c969f58c | 253 | |
601ef0d5 | 254 | if (unlikely(gfs2_withdrawn(sdp)) && |
ac915584 | 255 | (!sdp->sd_jdesc || gl != sdp->sd_jinode_gl)) { |
44b8db13 | 256 | *bhp = NULL; |
c969f58c | 257 | return -EIO; |
44b8db13 | 258 | } |
c969f58c SW |
259 | |
260 | *bhp = bh = gfs2_getbuf(gl, blkno, CREATE); | |
261 | ||
262 | lock_buffer(bh); | |
263 | if (buffer_uptodate(bh)) { | |
264 | unlock_buffer(bh); | |
39b0555f AG |
265 | flags &= ~DIO_WAIT; |
266 | } else { | |
267 | bh->b_end_io = end_buffer_read_sync; | |
268 | get_bh(bh); | |
269 | bhs[num++] = bh; | |
c969f58c | 270 | } |
39b0555f AG |
271 | |
272 | if (rahead) { | |
273 | bh = gfs2_getbuf(gl, blkno + 1, CREATE); | |
274 | ||
275 | lock_buffer(bh); | |
276 | if (buffer_uptodate(bh)) { | |
277 | unlock_buffer(bh); | |
278 | brelse(bh); | |
279 | } else { | |
280 | bh->b_end_io = end_buffer_read_sync; | |
281 | bhs[num++] = bh; | |
282 | } | |
283 | } | |
284 | ||
70fd7614 | 285 | gfs2_submit_bhs(REQ_OP_READ, REQ_META | REQ_PRIO, bhs, num); |
c969f58c SW |
286 | if (!(flags & DIO_WAIT)) |
287 | return 0; | |
288 | ||
39b0555f | 289 | bh = *bhp; |
c969f58c SW |
290 | wait_on_buffer(bh); |
291 | if (unlikely(!buffer_uptodate(bh))) { | |
292 | struct gfs2_trans *tr = current->journal_info; | |
9862ca05 | 293 | if (tr && test_bit(TR_TOUCHED, &tr->tr_flags)) |
9e1a9ecd | 294 | gfs2_io_error_bh_wd(sdp, bh); |
c969f58c | 295 | brelse(bh); |
44b8db13 | 296 | *bhp = NULL; |
c969f58c | 297 | return -EIO; |
7276b3b0 | 298 | } |
b3b94faa | 299 | |
7276b3b0 | 300 | return 0; |
b3b94faa DT |
301 | } |
302 | ||
303 | /** | |
7276b3b0 | 304 | * gfs2_meta_wait - Reread a block from disk |
b3b94faa | 305 | * @sdp: the filesystem |
7276b3b0 | 306 | * @bh: The block to wait for |
b3b94faa DT |
307 | * |
308 | * Returns: errno | |
309 | */ | |
310 | ||
7276b3b0 | 311 | int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh) |
b3b94faa | 312 | { |
eb43e660 | 313 | if (unlikely(gfs2_withdrawn(sdp))) |
b3b94faa DT |
314 | return -EIO; |
315 | ||
7276b3b0 | 316 | wait_on_buffer(bh); |
b3b94faa | 317 | |
7276b3b0 SW |
318 | if (!buffer_uptodate(bh)) { |
319 | struct gfs2_trans *tr = current->journal_info; | |
9862ca05 | 320 | if (tr && test_bit(TR_TOUCHED, &tr->tr_flags)) |
9e1a9ecd | 321 | gfs2_io_error_bh_wd(sdp, bh); |
7276b3b0 | 322 | return -EIO; |
b3b94faa | 323 | } |
eb43e660 | 324 | if (unlikely(gfs2_withdrawn(sdp))) |
7276b3b0 | 325 | return -EIO; |
b3b94faa DT |
326 | |
327 | return 0; | |
328 | } | |
329 | ||
68cd4ce2 | 330 | void gfs2_remove_from_journal(struct buffer_head *bh, int meta) |
16615be1 | 331 | { |
009d8518 SW |
332 | struct address_space *mapping = bh->b_page->mapping; |
333 | struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping); | |
16615be1 | 334 | struct gfs2_bufdata *bd = bh->b_private; |
68cd4ce2 | 335 | struct gfs2_trans *tr = current->journal_info; |
502be2a3 | 336 | int was_pinned = 0; |
009d8518 | 337 | |
16615be1 | 338 | if (test_clear_buffer_pinned(bh)) { |
627c10b7 | 339 | trace_gfs2_pin(bd, 0); |
5e687eac | 340 | atomic_dec(&sdp->sd_log_pinned); |
c0752aa7 | 341 | list_del_init(&bd->bd_list); |
68cd4ce2 | 342 | if (meta == REMOVE_META) |
16615be1 | 343 | tr->tr_num_buf_rm++; |
022ef4fe | 344 | else |
16615be1 | 345 | tr->tr_num_databuf_rm++; |
9862ca05 | 346 | set_bit(TR_TOUCHED, &tr->tr_flags); |
502be2a3 | 347 | was_pinned = 1; |
16615be1 SW |
348 | brelse(bh); |
349 | } | |
350 | if (bd) { | |
16ca9412 | 351 | if (bd->bd_tr) { |
16615be1 | 352 | gfs2_trans_add_revoke(sdp, bd); |
502be2a3 BP |
353 | } else if (was_pinned) { |
354 | bh->b_private = NULL; | |
355 | kmem_cache_free(gfs2_bufdata_cachep, bd); | |
68942870 BP |
356 | } else if (!list_empty(&bd->bd_ail_st_list) && |
357 | !list_empty(&bd->bd_ail_gl_list)) { | |
358 | gfs2_remove_from_ail(bd); | |
16615be1 SW |
359 | } |
360 | } | |
361 | clear_buffer_dirty(bh); | |
362 | clear_buffer_uptodate(bh); | |
363 | } | |
364 | ||
b3b94faa | 365 | /** |
68942870 BP |
366 | * gfs2_ail1_wipe - remove deleted/freed buffers from the ail1 list |
367 | * @sdp: superblock | |
368 | * @bstart: starting block address of buffers to remove | |
369 | * @blen: length of buffers to be removed | |
370 | * | |
371 | * This function is called from gfs2_journal wipe, whose job is to remove | |
372 | * buffers, corresponding to deleted blocks, from the journal. If we find any | |
373 | * bufdata elements on the system ail1 list, they haven't been written to | |
374 | * the journal yet. So we remove them. | |
375 | */ | |
376 | static void gfs2_ail1_wipe(struct gfs2_sbd *sdp, u64 bstart, u32 blen) | |
377 | { | |
378 | struct gfs2_trans *tr, *s; | |
379 | struct gfs2_bufdata *bd, *bs; | |
380 | struct buffer_head *bh; | |
381 | u64 end = bstart + blen; | |
382 | ||
383 | gfs2_log_lock(sdp); | |
384 | spin_lock(&sdp->sd_ail_lock); | |
385 | list_for_each_entry_safe(tr, s, &sdp->sd_ail1_list, tr_list) { | |
386 | list_for_each_entry_safe(bd, bs, &tr->tr_ail1_list, | |
387 | bd_ail_st_list) { | |
388 | bh = bd->bd_bh; | |
389 | if (bh->b_blocknr < bstart || bh->b_blocknr >= end) | |
390 | continue; | |
391 | ||
392 | gfs2_remove_from_journal(bh, REMOVE_JDATA); | |
393 | } | |
394 | } | |
395 | spin_unlock(&sdp->sd_ail_lock); | |
396 | gfs2_log_unlock(sdp); | |
397 | } | |
398 | ||
399 | static struct buffer_head *gfs2_getjdatabuf(struct gfs2_inode *ip, u64 blkno) | |
400 | { | |
401 | struct address_space *mapping = ip->i_inode.i_mapping; | |
402 | struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); | |
403 | struct page *page; | |
404 | struct buffer_head *bh; | |
405 | unsigned int shift = PAGE_SHIFT - sdp->sd_sb.sb_bsize_shift; | |
406 | unsigned long index = blkno >> shift; /* convert block to page */ | |
407 | unsigned int bufnum = blkno - (index << shift); | |
408 | ||
409 | page = find_get_page_flags(mapping, index, FGP_LOCK|FGP_ACCESSED); | |
410 | if (!page) | |
411 | return NULL; | |
412 | if (!page_has_buffers(page)) { | |
413 | unlock_page(page); | |
414 | put_page(page); | |
415 | return NULL; | |
416 | } | |
417 | /* Locate header for our buffer within our page */ | |
418 | for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page) | |
419 | /* Do nothing */; | |
420 | get_bh(bh); | |
421 | unlock_page(page); | |
422 | put_page(page); | |
423 | return bh; | |
424 | } | |
425 | ||
426 | /** | |
427 | * gfs2_journal_wipe - make inode's buffers so they aren't dirty/pinned anymore | |
b3b94faa DT |
428 | * @ip: the inode who owns the buffers |
429 | * @bstart: the first buffer in the run | |
430 | * @blen: the number of buffers in the run | |
431 | * | |
432 | */ | |
433 | ||
68942870 | 434 | void gfs2_journal_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen) |
b3b94faa | 435 | { |
feaa7bba | 436 | struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); |
b3b94faa | 437 | struct buffer_head *bh; |
68942870 | 438 | int ty; |
b3b94faa | 439 | |
68942870 | 440 | gfs2_ail1_wipe(sdp, bstart, blen); |
b3b94faa | 441 | while (blen) { |
68942870 | 442 | ty = REMOVE_META; |
6802e340 | 443 | bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE); |
68942870 BP |
444 | if (!bh && gfs2_is_jdata(ip)) { |
445 | bh = gfs2_getjdatabuf(ip, bstart); | |
446 | ty = REMOVE_JDATA; | |
447 | } | |
b3b94faa | 448 | if (bh) { |
1ad38c43 SW |
449 | lock_buffer(bh); |
450 | gfs2_log_lock(sdp); | |
68942870 BP |
451 | spin_lock(&sdp->sd_ail_lock); |
452 | gfs2_remove_from_journal(bh, ty); | |
453 | spin_unlock(&sdp->sd_ail_lock); | |
1ad38c43 | 454 | gfs2_log_unlock(sdp); |
b3b94faa | 455 | unlock_buffer(bh); |
b3b94faa DT |
456 | brelse(bh); |
457 | } | |
458 | ||
459 | bstart++; | |
460 | blen--; | |
461 | } | |
462 | } | |
463 | ||
b3b94faa DT |
464 | /** |
465 | * gfs2_meta_indirect_buffer - Get a metadata buffer | |
466 | * @ip: The GFS2 inode | |
467 | * @height: The level of this buf in the metadata (indir addr) tree (if any) | |
468 | * @num: The block number (device relative) of the buffer | |
b3b94faa DT |
469 | * @bhp: the buffer is returned here |
470 | * | |
b3b94faa DT |
471 | * Returns: errno |
472 | */ | |
473 | ||
cd915493 | 474 | int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num, |
f2f9c812 | 475 | struct buffer_head **bhp) |
b3b94faa | 476 | { |
7276b3b0 SW |
477 | struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); |
478 | struct gfs2_glock *gl = ip->i_gl; | |
f91a0d3e SW |
479 | struct buffer_head *bh; |
480 | int ret = 0; | |
f2f9c812 | 481 | u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI; |
c8d57703 AG |
482 | int rahead = 0; |
483 | ||
484 | if (num == ip->i_no_addr) | |
485 | rahead = ip->i_rahead; | |
b3b94faa | 486 | |
c8d57703 | 487 | ret = gfs2_meta_read(gl, num, DIO_WAIT, rahead, &bh); |
f2f9c812 BP |
488 | if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) { |
489 | brelse(bh); | |
490 | ret = -EIO; | |
61eaadcd BP |
491 | } else { |
492 | *bhp = bh; | |
b3b94faa | 493 | } |
f91a0d3e | 494 | return ret; |
b3b94faa DT |
495 | } |
496 | ||
497 | /** | |
498 | * gfs2_meta_ra - start readahead on an extent of a file | |
499 | * @gl: the glock the blocks belong to | |
500 | * @dblock: the starting disk block | |
501 | * @extlen: the number of blocks in the extent | |
502 | * | |
7276b3b0 | 503 | * returns: the first buffer in the extent |
b3b94faa DT |
504 | */ |
505 | ||
7276b3b0 | 506 | struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen) |
b3b94faa | 507 | { |
15562c43 | 508 | struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; |
b3b94faa | 509 | struct buffer_head *first_bh, *bh; |
cd915493 | 510 | u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >> |
568f4c96 | 511 | sdp->sd_sb.sb_bsize_shift; |
b3b94faa | 512 | |
7276b3b0 SW |
513 | BUG_ON(!extlen); |
514 | ||
515 | if (max_ra < 1) | |
516 | max_ra = 1; | |
b3b94faa DT |
517 | if (extlen > max_ra) |
518 | extlen = max_ra; | |
519 | ||
6802e340 | 520 | first_bh = gfs2_getbuf(gl, dblock, CREATE); |
b3b94faa DT |
521 | |
522 | if (buffer_uptodate(first_bh)) | |
523 | goto out; | |
7276b3b0 | 524 | if (!buffer_locked(first_bh)) |
e477b24b | 525 | ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1, &first_bh); |
b3b94faa DT |
526 | |
527 | dblock++; | |
528 | extlen--; | |
529 | ||
530 | while (extlen) { | |
6802e340 | 531 | bh = gfs2_getbuf(gl, dblock, CREATE); |
b3b94faa | 532 | |
7276b3b0 | 533 | if (!buffer_uptodate(bh) && !buffer_locked(bh)) |
e477b24b CL |
534 | ll_rw_block(REQ_OP_READ, |
535 | REQ_RAHEAD | REQ_META | REQ_PRIO, | |
536 | 1, &bh); | |
7276b3b0 | 537 | brelse(bh); |
b3b94faa DT |
538 | dblock++; |
539 | extlen--; | |
7276b3b0 SW |
540 | if (!buffer_locked(first_bh) && buffer_uptodate(first_bh)) |
541 | goto out; | |
b3b94faa DT |
542 | } |
543 | ||
7276b3b0 | 544 | wait_on_buffer(first_bh); |
a91ea69f | 545 | out: |
7276b3b0 | 546 | return first_bh; |
b3b94faa DT |
547 | } |
548 |