1 /*
2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
4 *
5 * This copyrighted material is made available to anyone wishing to use,
6 * modify, copy, or redistribute it subject to the terms and conditions
7 * of the GNU General Public License version 2.
8 */
9
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/completion.h>
14 #include <linux/buffer_head.h>
15 #include <linux/mm.h>
16 #include <linux/pagemap.h>
17 #include <linux/writeback.h>
18 #include <linux/swap.h>
19 #include <linux/delay.h>
20 #include <linux/bio.h>
21 #include <linux/gfs2_ondisk.h>
22
23 #include "gfs2.h"
24 #include "incore.h"
25 #include "glock.h"
26 #include "glops.h"
27 #include "inode.h"
28 #include "log.h"
29 #include "lops.h"
30 #include "meta_io.h"
31 #include "rgrp.h"
32 #include "trans.h"
33 #include "util.h"
34 #include "trace_gfs2.h"
35
gfs2_aspace_writepage(struct page * page,struct writeback_control * wbc)36 static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wbc)
37 {
38 struct buffer_head *bh, *head;
39 int nr_underway = 0;
40 int write_flags = REQ_META | REQ_PRIO | wbc_to_write_flags(wbc);
41
42 BUG_ON(!PageLocked(page));
43 BUG_ON(!page_has_buffers(page));
44
45 head = page_buffers(page);
46 bh = head;
47
48 do {
49 if (!buffer_mapped(bh))
50 continue;
51 /*
52 * If it's a fully non-blocking write attempt and we cannot
53 * lock the buffer then redirty the page. Note that this can
54 * potentially cause a busy-wait loop from flusher thread and kswapd
55 * activity, but those code paths have their own higher-level
56 * throttling.
57 */
58 if (wbc->sync_mode != WB_SYNC_NONE) {
59 lock_buffer(bh);
60 } else if (!trylock_buffer(bh)) {
61 redirty_page_for_writepage(wbc, page);
62 continue;
63 }
64 if (test_clear_buffer_dirty(bh)) {
65 mark_buffer_async_write(bh);
66 } else {
67 unlock_buffer(bh);
68 }
69 } while ((bh = bh->b_this_page) != head);
70
71 /*
72 * The page and its buffers are protected by PageWriteback(), so we can
73 * drop the bh refcounts early.
74 */
75 BUG_ON(PageWriteback(page));
76 set_page_writeback(page);
77
78 do {
79 struct buffer_head *next = bh->b_this_page;
80 if (buffer_async_write(bh)) {
81 submit_bh(REQ_OP_WRITE, write_flags, bh);
82 nr_underway++;
83 }
84 bh = next;
85 } while (bh != head);
86 unlock_page(page);
87
88 if (nr_underway == 0)
89 end_page_writeback(page);
90
91 return 0;
92 }
93
94 const struct address_space_operations gfs2_meta_aops = {
95 .writepage = gfs2_aspace_writepage,
96 .releasepage = gfs2_releasepage,
97 };
98
99 const struct address_space_operations gfs2_rgrp_aops = {
100 .writepage = gfs2_aspace_writepage,
101 .releasepage = gfs2_releasepage,
102 };
103
104 /**
105 * gfs2_getbuf - Get a buffer with a given address space
106 * @gl: the glock
107 * @blkno: the block number (filesystem scope)
108 * @create: 1 if the buffer should be created
109 *
110 * Returns: the buffer
111 */
112
gfs2_getbuf(struct gfs2_glock * gl,u64 blkno,int create)113 struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
114 {
115 struct address_space *mapping = gfs2_glock2aspace(gl);
116 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
117 struct page *page;
118 struct buffer_head *bh;
119 unsigned int shift;
120 unsigned long index;
121 unsigned int bufnum;
122
123 if (mapping == NULL)
124 mapping = &sdp->sd_aspace;
125
126 shift = PAGE_SHIFT - sdp->sd_sb.sb_bsize_shift;
127 index = blkno >> shift; /* convert block to page */
128 bufnum = blkno - (index << shift); /* block buf index within page */
129
130 if (create) {
131 for (;;) {
132 page = grab_cache_page(mapping, index);
133 if (page)
134 break;
135 yield();
136 }
137 } else {
138 page = find_get_page_flags(mapping, index,
139 FGP_LOCK|FGP_ACCESSED);
140 if (!page)
141 return NULL;
142 }
143
144 if (!page_has_buffers(page))
145 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
146
147 /* Locate header for our buffer within our page */
148 for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
149 /* Do nothing */;
150 get_bh(bh);
151
152 if (!buffer_mapped(bh))
153 map_bh(bh, sdp->sd_vfs, blkno);
154
155 unlock_page(page);
156 put_page(page);
157
158 return bh;
159 }
160
meta_prep_new(struct buffer_head * bh)161 static void meta_prep_new(struct buffer_head *bh)
162 {
163 struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
164
165 lock_buffer(bh);
166 clear_buffer_dirty(bh);
167 set_buffer_uptodate(bh);
168 unlock_buffer(bh);
169
170 mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
171 }
172
173 /**
174 * gfs2_meta_new - Get a block
175 * @gl: The glock associated with this block
176 * @blkno: The block number
177 *
178 * Returns: The buffer
179 */
180
gfs2_meta_new(struct gfs2_glock * gl,u64 blkno)181 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
182 {
183 struct buffer_head *bh;
184 bh = gfs2_getbuf(gl, blkno, CREATE);
185 meta_prep_new(bh);
186 return bh;
187 }
188
gfs2_meta_read_endio(struct bio * bio)189 static void gfs2_meta_read_endio(struct bio *bio)
190 {
191 struct bio_vec *bvec;
192 int i;
193
194 bio_for_each_segment_all(bvec, bio, i) {
195 struct page *page = bvec->bv_page;
196 struct buffer_head *bh = page_buffers(page);
197 unsigned int len = bvec->bv_len;
198
199 while (bh_offset(bh) < bvec->bv_offset)
200 bh = bh->b_this_page;
201 do {
202 struct buffer_head *next = bh->b_this_page;
203 len -= bh->b_size;
204 bh->b_end_io(bh, !bio->bi_status);
205 bh = next;
206 } while (bh && len);
207 }
208 bio_put(bio);
209 }
210
211 /*
212 * Submit several consecutive buffer head I/O requests as a single bio I/O
213 * request. (See submit_bh_wbc.)
214 */
gfs2_submit_bhs(int op,int op_flags,struct buffer_head * bhs[],int num)215 static void gfs2_submit_bhs(int op, int op_flags, struct buffer_head *bhs[],
216 int num)
217 {
218 while (num > 0) {
219 struct buffer_head *bh = *bhs;
220 struct bio *bio;
221
222 bio = bio_alloc(GFP_NOIO, num);
223 bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
224 bio_set_dev(bio, bh->b_bdev);
225 while (num > 0) {
226 bh = *bhs;
227 if (!bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh))) {
228 BUG_ON(bio->bi_iter.bi_size == 0);
229 break;
230 }
231 bhs++;
232 num--;
233 }
234 bio->bi_end_io = gfs2_meta_read_endio;
235 bio_set_op_attrs(bio, op, op_flags);
236 submit_bio(bio);
237 }
238 }
239
240 /**
241 * gfs2_meta_read - Read a block from disk
242 * @gl: The glock covering the block
243 * @blkno: The block number
244 * @flags: flags
245 * @bhp: the place where the buffer is returned (NULL on failure)
246 *
247 * Returns: errno
248 */
249
gfs2_meta_read(struct gfs2_glock * gl,u64 blkno,int flags,int rahead,struct buffer_head ** bhp)250 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
251 int rahead, struct buffer_head **bhp)
252 {
253 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
254 struct buffer_head *bh, *bhs[2];
255 int num = 0;
256
257 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
258 *bhp = NULL;
259 return -EIO;
260 }
261
262 *bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
263
264 lock_buffer(bh);
265 if (buffer_uptodate(bh)) {
266 unlock_buffer(bh);
267 flags &= ~DIO_WAIT;
268 } else {
269 bh->b_end_io = end_buffer_read_sync;
270 get_bh(bh);
271 bhs[num++] = bh;
272 }
273
274 if (rahead) {
275 bh = gfs2_getbuf(gl, blkno + 1, CREATE);
276
277 lock_buffer(bh);
278 if (buffer_uptodate(bh)) {
279 unlock_buffer(bh);
280 brelse(bh);
281 } else {
282 bh->b_end_io = end_buffer_read_sync;
283 bhs[num++] = bh;
284 }
285 }
286
287 gfs2_submit_bhs(REQ_OP_READ, REQ_META | REQ_PRIO, bhs, num);
288 if (!(flags & DIO_WAIT))
289 return 0;
290
291 bh = *bhp;
292 wait_on_buffer(bh);
293 if (unlikely(!buffer_uptodate(bh))) {
294 struct gfs2_trans *tr = current->journal_info;
295 if (tr && test_bit(TR_TOUCHED, &tr->tr_flags))
296 gfs2_io_error_bh_wd(sdp, bh);
297 brelse(bh);
298 *bhp = NULL;
299 return -EIO;
300 }
301
302 return 0;
303 }
304
305 /**
306 * gfs2_meta_wait - Reread a block from disk
307 * @sdp: the filesystem
308 * @bh: The block to wait for
309 *
310 * Returns: errno
311 */
312
gfs2_meta_wait(struct gfs2_sbd * sdp,struct buffer_head * bh)313 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
314 {
315 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
316 return -EIO;
317
318 wait_on_buffer(bh);
319
320 if (!buffer_uptodate(bh)) {
321 struct gfs2_trans *tr = current->journal_info;
322 if (tr && test_bit(TR_TOUCHED, &tr->tr_flags))
323 gfs2_io_error_bh_wd(sdp, bh);
324 return -EIO;
325 }
326 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
327 return -EIO;
328
329 return 0;
330 }
331
gfs2_remove_from_journal(struct buffer_head * bh,int meta)332 void gfs2_remove_from_journal(struct buffer_head *bh, int meta)
333 {
334 struct address_space *mapping = bh->b_page->mapping;
335 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
336 struct gfs2_bufdata *bd = bh->b_private;
337 struct gfs2_trans *tr = current->journal_info;
338 int was_pinned = 0;
339
340 if (test_clear_buffer_pinned(bh)) {
341 trace_gfs2_pin(bd, 0);
342 atomic_dec(&sdp->sd_log_pinned);
343 list_del_init(&bd->bd_list);
344 if (meta == REMOVE_META)
345 tr->tr_num_buf_rm++;
346 else
347 tr->tr_num_databuf_rm++;
348 set_bit(TR_TOUCHED, &tr->tr_flags);
349 was_pinned = 1;
350 brelse(bh);
351 }
352 if (bd) {
353 spin_lock(&sdp->sd_ail_lock);
354 if (bd->bd_tr) {
355 gfs2_trans_add_revoke(sdp, bd);
356 } else if (was_pinned) {
357 bh->b_private = NULL;
358 kmem_cache_free(gfs2_bufdata_cachep, bd);
359 }
360 spin_unlock(&sdp->sd_ail_lock);
361 }
362 clear_buffer_dirty(bh);
363 clear_buffer_uptodate(bh);
364 }
365
366 /**
367 * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
368 * @ip: the inode who owns the buffers
369 * @bstart: the first buffer in the run
370 * @blen: the number of buffers in the run
371 *
372 */
373
gfs2_meta_wipe(struct gfs2_inode * ip,u64 bstart,u32 blen)374 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
375 {
376 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
377 struct buffer_head *bh;
378
379 while (blen) {
380 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
381 if (bh) {
382 lock_buffer(bh);
383 gfs2_log_lock(sdp);
384 gfs2_remove_from_journal(bh, REMOVE_META);
385 gfs2_log_unlock(sdp);
386 unlock_buffer(bh);
387 brelse(bh);
388 }
389
390 bstart++;
391 blen--;
392 }
393 }
394
395 /**
396 * gfs2_meta_indirect_buffer - Get a metadata buffer
397 * @ip: The GFS2 inode
398 * @height: The level of this buf in the metadata (indir addr) tree (if any)
399 * @num: The block number (device relative) of the buffer
400 * @bhp: the buffer is returned here
401 *
402 * Returns: errno
403 */
404
gfs2_meta_indirect_buffer(struct gfs2_inode * ip,int height,u64 num,struct buffer_head ** bhp)405 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
406 struct buffer_head **bhp)
407 {
408 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
409 struct gfs2_glock *gl = ip->i_gl;
410 struct buffer_head *bh;
411 int ret = 0;
412 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
413 int rahead = 0;
414
415 if (num == ip->i_no_addr)
416 rahead = ip->i_rahead;
417
418 ret = gfs2_meta_read(gl, num, DIO_WAIT, rahead, &bh);
419 if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
420 brelse(bh);
421 ret = -EIO;
422 } else {
423 *bhp = bh;
424 }
425 return ret;
426 }
427
428 /**
429 * gfs2_meta_ra - start readahead on an extent of a file
430 * @gl: the glock the blocks belong to
431 * @dblock: the starting disk block
432 * @extlen: the number of blocks in the extent
433 *
434 * returns: the first buffer in the extent
435 */
436
gfs2_meta_ra(struct gfs2_glock * gl,u64 dblock,u32 extlen)437 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
438 {
439 struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
440 struct buffer_head *first_bh, *bh;
441 u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
442 sdp->sd_sb.sb_bsize_shift;
443
444 BUG_ON(!extlen);
445
446 if (max_ra < 1)
447 max_ra = 1;
448 if (extlen > max_ra)
449 extlen = max_ra;
450
451 first_bh = gfs2_getbuf(gl, dblock, CREATE);
452
453 if (buffer_uptodate(first_bh))
454 goto out;
455 if (!buffer_locked(first_bh))
456 ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1, &first_bh);
457
458 dblock++;
459 extlen--;
460
461 while (extlen) {
462 bh = gfs2_getbuf(gl, dblock, CREATE);
463
464 if (!buffer_uptodate(bh) && !buffer_locked(bh))
465 ll_rw_block(REQ_OP_READ,
466 REQ_RAHEAD | REQ_META | REQ_PRIO,
467 1, &bh);
468 brelse(bh);
469 dblock++;
470 extlen--;
471 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
472 goto out;
473 }
474
475 wait_on_buffer(first_bh);
476 out:
477 return first_bh;
478 }
479
480