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_op = REQ_META | REQ_PRIO |
41 (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
42
43 BUG_ON(!PageLocked(page));
44 BUG_ON(!page_has_buffers(page));
45
46 head = page_buffers(page);
47 bh = head;
48
49 do {
50 if (!buffer_mapped(bh))
51 continue;
52 /*
53 * If it's a fully non-blocking write attempt and we cannot
54 * lock the buffer then redirty the page. Note that this can
55 * potentially cause a busy-wait loop from flusher thread and kswapd
56 * activity, but those code paths have their own higher-level
57 * throttling.
58 */
59 if (wbc->sync_mode != WB_SYNC_NONE) {
60 lock_buffer(bh);
61 } else if (!trylock_buffer(bh)) {
62 redirty_page_for_writepage(wbc, page);
63 continue;
64 }
65 if (test_clear_buffer_dirty(bh)) {
66 mark_buffer_async_write(bh);
67 } else {
68 unlock_buffer(bh);
69 }
70 } while ((bh = bh->b_this_page) != head);
71
72 /*
73 * The page and its buffers are protected by PageWriteback(), so we can
74 * drop the bh refcounts early.
75 */
76 BUG_ON(PageWriteback(page));
77 set_page_writeback(page);
78
79 do {
80 struct buffer_head *next = bh->b_this_page;
81 if (buffer_async_write(bh)) {
82 submit_bh(write_op, bh);
83 nr_underway++;
84 }
85 bh = next;
86 } while (bh != head);
87 unlock_page(page);
88
89 if (nr_underway == 0)
90 end_page_writeback(page);
91
92 return 0;
93 }
94
95 const struct address_space_operations gfs2_meta_aops = {
96 .writepage = gfs2_aspace_writepage,
97 .releasepage = gfs2_releasepage,
98 };
99
100 /**
101 * gfs2_meta_sync - Sync all buffers associated with a glock
102 * @gl: The glock
103 *
104 */
105
gfs2_meta_sync(struct gfs2_glock * gl)106 void gfs2_meta_sync(struct gfs2_glock *gl)
107 {
108 struct address_space *mapping = gfs2_glock2aspace(gl);
109 int error;
110
111 filemap_fdatawrite(mapping);
112 error = filemap_fdatawait(mapping);
113
114 if (error)
115 gfs2_io_error(gl->gl_sbd);
116 }
117
118 /**
119 * gfs2_getbuf - Get a buffer with a given address space
120 * @gl: the glock
121 * @blkno: the block number (filesystem scope)
122 * @create: 1 if the buffer should be created
123 *
124 * Returns: the buffer
125 */
126
gfs2_getbuf(struct gfs2_glock * gl,u64 blkno,int create)127 struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
128 {
129 struct address_space *mapping = gfs2_glock2aspace(gl);
130 struct gfs2_sbd *sdp = gl->gl_sbd;
131 struct page *page;
132 struct buffer_head *bh;
133 unsigned int shift;
134 unsigned long index;
135 unsigned int bufnum;
136
137 shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
138 index = blkno >> shift; /* convert block to page */
139 bufnum = blkno - (index << shift); /* block buf index within page */
140
141 if (create) {
142 for (;;) {
143 page = grab_cache_page(mapping, index);
144 if (page)
145 break;
146 yield();
147 }
148 } else {
149 page = find_lock_page(mapping, index);
150 if (!page)
151 return NULL;
152 }
153
154 if (!page_has_buffers(page))
155 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
156
157 /* Locate header for our buffer within our page */
158 for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
159 /* Do nothing */;
160 get_bh(bh);
161
162 if (!buffer_mapped(bh))
163 map_bh(bh, sdp->sd_vfs, blkno);
164
165 unlock_page(page);
166 mark_page_accessed(page);
167 page_cache_release(page);
168
169 return bh;
170 }
171
meta_prep_new(struct buffer_head * bh)172 static void meta_prep_new(struct buffer_head *bh)
173 {
174 struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
175
176 lock_buffer(bh);
177 clear_buffer_dirty(bh);
178 set_buffer_uptodate(bh);
179 unlock_buffer(bh);
180
181 mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
182 }
183
184 /**
185 * gfs2_meta_new - Get a block
186 * @gl: The glock associated with this block
187 * @blkno: The block number
188 *
189 * Returns: The buffer
190 */
191
gfs2_meta_new(struct gfs2_glock * gl,u64 blkno)192 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
193 {
194 struct buffer_head *bh;
195 bh = gfs2_getbuf(gl, blkno, CREATE);
196 meta_prep_new(bh);
197 return bh;
198 }
199
200 /**
201 * gfs2_meta_read - Read a block from disk
202 * @gl: The glock covering the block
203 * @blkno: The block number
204 * @flags: flags
205 * @bhp: the place where the buffer is returned (NULL on failure)
206 *
207 * Returns: errno
208 */
209
gfs2_meta_read(struct gfs2_glock * gl,u64 blkno,int flags,struct buffer_head ** bhp)210 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
211 struct buffer_head **bhp)
212 {
213 struct gfs2_sbd *sdp = gl->gl_sbd;
214 struct buffer_head *bh;
215
216 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
217 *bhp = NULL;
218 return -EIO;
219 }
220
221 *bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
222
223 lock_buffer(bh);
224 if (buffer_uptodate(bh)) {
225 unlock_buffer(bh);
226 return 0;
227 }
228 bh->b_end_io = end_buffer_read_sync;
229 get_bh(bh);
230 submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh);
231 if (!(flags & DIO_WAIT))
232 return 0;
233
234 wait_on_buffer(bh);
235 if (unlikely(!buffer_uptodate(bh))) {
236 struct gfs2_trans *tr = current->journal_info;
237 if (tr && tr->tr_touched)
238 gfs2_io_error_bh(sdp, bh);
239 brelse(bh);
240 *bhp = NULL;
241 return -EIO;
242 }
243
244 return 0;
245 }
246
247 /**
248 * gfs2_meta_wait - Reread a block from disk
249 * @sdp: the filesystem
250 * @bh: The block to wait for
251 *
252 * Returns: errno
253 */
254
gfs2_meta_wait(struct gfs2_sbd * sdp,struct buffer_head * bh)255 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
256 {
257 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
258 return -EIO;
259
260 wait_on_buffer(bh);
261
262 if (!buffer_uptodate(bh)) {
263 struct gfs2_trans *tr = current->journal_info;
264 if (tr && tr->tr_touched)
265 gfs2_io_error_bh(sdp, bh);
266 return -EIO;
267 }
268 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
269 return -EIO;
270
271 return 0;
272 }
273
gfs2_remove_from_journal(struct buffer_head * bh,struct gfs2_trans * tr,int meta)274 void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
275 {
276 struct address_space *mapping = bh->b_page->mapping;
277 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
278 struct gfs2_bufdata *bd = bh->b_private;
279
280 if (test_clear_buffer_pinned(bh)) {
281 trace_gfs2_pin(bd, 0);
282 atomic_dec(&sdp->sd_log_pinned);
283 list_del_init(&bd->bd_list);
284 if (meta) {
285 gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
286 sdp->sd_log_num_buf--;
287 tr->tr_num_buf_rm++;
288 } else {
289 gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
290 sdp->sd_log_num_databuf--;
291 tr->tr_num_databuf_rm++;
292 }
293 tr->tr_touched = 1;
294 brelse(bh);
295 }
296 if (bd) {
297 spin_lock(&sdp->sd_ail_lock);
298 if (bd->bd_tr) {
299 gfs2_remove_from_ail(bd);
300 bh->b_private = NULL;
301 bd->bd_bh = NULL;
302 bd->bd_blkno = bh->b_blocknr;
303 gfs2_trans_add_revoke(sdp, bd);
304 }
305 spin_unlock(&sdp->sd_ail_lock);
306 }
307 clear_buffer_dirty(bh);
308 clear_buffer_uptodate(bh);
309 }
310
311 /**
312 * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
313 * @ip: the inode who owns the buffers
314 * @bstart: the first buffer in the run
315 * @blen: the number of buffers in the run
316 *
317 */
318
gfs2_meta_wipe(struct gfs2_inode * ip,u64 bstart,u32 blen)319 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
320 {
321 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
322 struct buffer_head *bh;
323
324 while (blen) {
325 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
326 if (bh) {
327 lock_buffer(bh);
328 gfs2_log_lock(sdp);
329 gfs2_remove_from_journal(bh, current->journal_info, 1);
330 gfs2_log_unlock(sdp);
331 unlock_buffer(bh);
332 brelse(bh);
333 }
334
335 bstart++;
336 blen--;
337 }
338 }
339
340 /**
341 * gfs2_meta_indirect_buffer - Get a metadata buffer
342 * @ip: The GFS2 inode
343 * @height: The level of this buf in the metadata (indir addr) tree (if any)
344 * @num: The block number (device relative) of the buffer
345 * @bhp: the buffer is returned here
346 *
347 * Returns: errno
348 */
349
gfs2_meta_indirect_buffer(struct gfs2_inode * ip,int height,u64 num,struct buffer_head ** bhp)350 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
351 struct buffer_head **bhp)
352 {
353 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
354 struct gfs2_glock *gl = ip->i_gl;
355 struct buffer_head *bh;
356 int ret = 0;
357 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
358
359 ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
360 if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
361 brelse(bh);
362 ret = -EIO;
363 }
364 *bhp = bh;
365 return ret;
366 }
367
368 /**
369 * gfs2_meta_ra - start readahead on an extent of a file
370 * @gl: the glock the blocks belong to
371 * @dblock: the starting disk block
372 * @extlen: the number of blocks in the extent
373 *
374 * returns: the first buffer in the extent
375 */
376
gfs2_meta_ra(struct gfs2_glock * gl,u64 dblock,u32 extlen)377 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
378 {
379 struct gfs2_sbd *sdp = gl->gl_sbd;
380 struct buffer_head *first_bh, *bh;
381 u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
382 sdp->sd_sb.sb_bsize_shift;
383
384 BUG_ON(!extlen);
385
386 if (max_ra < 1)
387 max_ra = 1;
388 if (extlen > max_ra)
389 extlen = max_ra;
390
391 first_bh = gfs2_getbuf(gl, dblock, CREATE);
392
393 if (buffer_uptodate(first_bh))
394 goto out;
395 if (!buffer_locked(first_bh))
396 ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh);
397
398 dblock++;
399 extlen--;
400
401 while (extlen) {
402 bh = gfs2_getbuf(gl, dblock, CREATE);
403
404 if (!buffer_uptodate(bh) && !buffer_locked(bh))
405 ll_rw_block(READA | REQ_META, 1, &bh);
406 brelse(bh);
407 dblock++;
408 extlen--;
409 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
410 goto out;
411 }
412
413 wait_on_buffer(first_bh);
414 out:
415 return first_bh;
416 }
417
418