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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
36static 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 pdflush 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
95const 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
106void 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
127struct 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
172static 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
192struct 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
210int 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 return -EIO;
218
219 *bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
220
221 lock_buffer(bh);
222 if (buffer_uptodate(bh)) {
223 unlock_buffer(bh);
224 return 0;
225 }
226 bh->b_end_io = end_buffer_read_sync;
227 get_bh(bh);
228 submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh);
229 if (!(flags & DIO_WAIT))
230 return 0;
231
232 wait_on_buffer(bh);
233 if (unlikely(!buffer_uptodate(bh))) {
234 struct gfs2_trans *tr = current->journal_info;
235 if (tr && tr->tr_touched)
236 gfs2_io_error_bh(sdp, bh);
237 brelse(bh);
238 return -EIO;
239 }
240
241 return 0;
242}
243
244/**
245 * gfs2_meta_wait - Reread a block from disk
246 * @sdp: the filesystem
247 * @bh: The block to wait for
248 *
249 * Returns: errno
250 */
251
252int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
253{
254 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
255 return -EIO;
256
257 wait_on_buffer(bh);
258
259 if (!buffer_uptodate(bh)) {
260 struct gfs2_trans *tr = current->journal_info;
261 if (tr && tr->tr_touched)
262 gfs2_io_error_bh(sdp, bh);
263 return -EIO;
264 }
265 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
266 return -EIO;
267
268 return 0;
269}
270
271/**
272 * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
273 * @gl: the glock the buffer belongs to
274 * @bh: The buffer to be attached to
275 * @meta: Flag to indicate whether its metadata or not
276 */
277
278void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
279 int meta)
280{
281 struct gfs2_bufdata *bd;
282
283 if (meta)
284 lock_page(bh->b_page);
285
286 if (bh->b_private) {
287 if (meta)
288 unlock_page(bh->b_page);
289 return;
290 }
291
292 bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
293 bd->bd_bh = bh;
294 bd->bd_gl = gl;
295
296 if (meta)
297 lops_init_le(bd, &gfs2_buf_lops);
298 else
299 lops_init_le(bd, &gfs2_databuf_lops);
300 bh->b_private = bd;
301
302 if (meta)
303 unlock_page(bh->b_page);
304}
305
306void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
307{
308 struct address_space *mapping = bh->b_page->mapping;
309 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
310 struct gfs2_bufdata *bd = bh->b_private;
311
312 if (test_clear_buffer_pinned(bh)) {
313 trace_gfs2_pin(bd, 0);
314 atomic_dec(&sdp->sd_log_pinned);
315 list_del_init(&bd->bd_list);
316 if (meta) {
317 gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
318 sdp->sd_log_num_buf--;
319 tr->tr_num_buf_rm++;
320 } else {
321 gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
322 sdp->sd_log_num_databuf--;
323 tr->tr_num_databuf_rm++;
324 }
325 tr->tr_touched = 1;
326 brelse(bh);
327 }
328 if (bd) {
329 spin_lock(&sdp->sd_ail_lock);
330 if (bd->bd_ail) {
331 gfs2_remove_from_ail(bd);
332 bh->b_private = NULL;
333 bd->bd_bh = NULL;
334 bd->bd_blkno = bh->b_blocknr;
335 gfs2_trans_add_revoke(sdp, bd);
336 }
337 spin_unlock(&sdp->sd_ail_lock);
338 }
339 clear_buffer_dirty(bh);
340 clear_buffer_uptodate(bh);
341}
342
343/**
344 * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
345 * @ip: the inode who owns the buffers
346 * @bstart: the first buffer in the run
347 * @blen: the number of buffers in the run
348 *
349 */
350
351void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
352{
353 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
354 struct buffer_head *bh;
355
356 while (blen) {
357 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
358 if (bh) {
359 lock_buffer(bh);
360 gfs2_log_lock(sdp);
361 gfs2_remove_from_journal(bh, current->journal_info, 1);
362 gfs2_log_unlock(sdp);
363 unlock_buffer(bh);
364 brelse(bh);
365 }
366
367 bstart++;
368 blen--;
369 }
370}
371
372/**
373 * gfs2_meta_indirect_buffer - Get a metadata buffer
374 * @ip: The GFS2 inode
375 * @height: The level of this buf in the metadata (indir addr) tree (if any)
376 * @num: The block number (device relative) of the buffer
377 * @bhp: the buffer is returned here
378 *
379 * Returns: errno
380 */
381
382int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
383 struct buffer_head **bhp)
384{
385 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
386 struct gfs2_glock *gl = ip->i_gl;
387 struct buffer_head *bh;
388 int ret = 0;
389 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
390
391 ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
392 if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
393 brelse(bh);
394 ret = -EIO;
395 }
396 *bhp = bh;
397 return ret;
398}
399
400/**
401 * gfs2_meta_ra - start readahead on an extent of a file
402 * @gl: the glock the blocks belong to
403 * @dblock: the starting disk block
404 * @extlen: the number of blocks in the extent
405 *
406 * returns: the first buffer in the extent
407 */
408
409struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
410{
411 struct gfs2_sbd *sdp = gl->gl_sbd;
412 struct buffer_head *first_bh, *bh;
413 u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
414 sdp->sd_sb.sb_bsize_shift;
415
416 BUG_ON(!extlen);
417
418 if (max_ra < 1)
419 max_ra = 1;
420 if (extlen > max_ra)
421 extlen = max_ra;
422
423 first_bh = gfs2_getbuf(gl, dblock, CREATE);
424
425 if (buffer_uptodate(first_bh))
426 goto out;
427 if (!buffer_locked(first_bh))
428 ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh);
429
430 dblock++;
431 extlen--;
432
433 while (extlen) {
434 bh = gfs2_getbuf(gl, dblock, CREATE);
435
436 if (!buffer_uptodate(bh) && !buffer_locked(bh))
437 ll_rw_block(READA | REQ_META, 1, &bh);
438 brelse(bh);
439 dblock++;
440 extlen--;
441 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
442 goto out;
443 }
444
445 wait_on_buffer(first_bh);
446out:
447 return first_bh;
448}
449