xref: /openbmc/linux/fs/gfs2/meta_io.c (revision de2bdb3d)
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 
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 |
41 		(wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : 0);
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(REQ_OP_WRITE, write_flags, 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 const struct address_space_operations gfs2_rgrp_aops = {
101 	.writepage = gfs2_aspace_writepage,
102 	.releasepage = gfs2_releasepage,
103 };
104 
105 /**
106  * gfs2_getbuf - Get a buffer with a given address space
107  * @gl: the glock
108  * @blkno: the block number (filesystem scope)
109  * @create: 1 if the buffer should be created
110  *
111  * Returns: the buffer
112  */
113 
114 struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
115 {
116 	struct address_space *mapping = gfs2_glock2aspace(gl);
117 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
118 	struct page *page;
119 	struct buffer_head *bh;
120 	unsigned int shift;
121 	unsigned long index;
122 	unsigned int bufnum;
123 
124 	if (mapping == NULL)
125 		mapping = &sdp->sd_aspace;
126 
127 	shift = PAGE_SHIFT - sdp->sd_sb.sb_bsize_shift;
128 	index = blkno >> shift;             /* convert block to page */
129 	bufnum = blkno - (index << shift);  /* block buf index within page */
130 
131 	if (create) {
132 		for (;;) {
133 			page = grab_cache_page(mapping, index);
134 			if (page)
135 				break;
136 			yield();
137 		}
138 	} else {
139 		page = find_get_page_flags(mapping, index,
140 						FGP_LOCK|FGP_ACCESSED);
141 		if (!page)
142 			return NULL;
143 	}
144 
145 	if (!page_has_buffers(page))
146 		create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
147 
148 	/* Locate header for our buffer within our page */
149 	for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
150 		/* Do nothing */;
151 	get_bh(bh);
152 
153 	if (!buffer_mapped(bh))
154 		map_bh(bh, sdp->sd_vfs, blkno);
155 
156 	unlock_page(page);
157 	put_page(page);
158 
159 	return bh;
160 }
161 
162 static void meta_prep_new(struct buffer_head *bh)
163 {
164 	struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
165 
166 	lock_buffer(bh);
167 	clear_buffer_dirty(bh);
168 	set_buffer_uptodate(bh);
169 	unlock_buffer(bh);
170 
171 	mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
172 }
173 
174 /**
175  * gfs2_meta_new - Get a block
176  * @gl: The glock associated with this block
177  * @blkno: The block number
178  *
179  * Returns: The buffer
180  */
181 
182 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
183 {
184 	struct buffer_head *bh;
185 	bh = gfs2_getbuf(gl, blkno, CREATE);
186 	meta_prep_new(bh);
187 	return bh;
188 }
189 
190 static void gfs2_meta_read_endio(struct bio *bio)
191 {
192 	struct bio_vec *bvec;
193 	int i;
194 
195 	bio_for_each_segment_all(bvec, bio, i) {
196 		struct page *page = bvec->bv_page;
197 		struct buffer_head *bh = page_buffers(page);
198 		unsigned int len = bvec->bv_len;
199 
200 		while (bh_offset(bh) < bvec->bv_offset)
201 			bh = bh->b_this_page;
202 		do {
203 			struct buffer_head *next = bh->b_this_page;
204 			len -= bh->b_size;
205 			bh->b_end_io(bh, !bio->bi_error);
206 			bh = next;
207 		} while (bh && len);
208 	}
209 	bio_put(bio);
210 }
211 
212 /*
213  * Submit several consecutive buffer head I/O requests as a single bio I/O
214  * request.  (See submit_bh_wbc.)
215  */
216 static void gfs2_submit_bhs(int op, int op_flags, struct buffer_head *bhs[],
217 			    int num)
218 {
219 	while (num > 0) {
220 		struct buffer_head *bh = *bhs;
221 		struct bio *bio;
222 
223 		bio = bio_alloc(GFP_NOIO, num);
224 		bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
225 		bio->bi_bdev = bh->b_bdev;
226 		while (num > 0) {
227 			bh = *bhs;
228 			if (!bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh))) {
229 				BUG_ON(bio->bi_iter.bi_size == 0);
230 				break;
231 			}
232 			bhs++;
233 			num--;
234 		}
235 		bio->bi_end_io = gfs2_meta_read_endio;
236 		bio_set_op_attrs(bio, op, op_flags);
237 		submit_bio(bio);
238 	}
239 }
240 
241 /**
242  * gfs2_meta_read - Read a block from disk
243  * @gl: The glock covering the block
244  * @blkno: The block number
245  * @flags: flags
246  * @bhp: the place where the buffer is returned (NULL on failure)
247  *
248  * Returns: errno
249  */
250 
251 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
252 		   int rahead, struct buffer_head **bhp)
253 {
254 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
255 	struct buffer_head *bh, *bhs[2];
256 	int num = 0;
257 
258 	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
259 		*bhp = NULL;
260 		return -EIO;
261 	}
262 
263 	*bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
264 
265 	lock_buffer(bh);
266 	if (buffer_uptodate(bh)) {
267 		unlock_buffer(bh);
268 		flags &= ~DIO_WAIT;
269 	} else {
270 		bh->b_end_io = end_buffer_read_sync;
271 		get_bh(bh);
272 		bhs[num++] = bh;
273 	}
274 
275 	if (rahead) {
276 		bh = gfs2_getbuf(gl, blkno + 1, CREATE);
277 
278 		lock_buffer(bh);
279 		if (buffer_uptodate(bh)) {
280 			unlock_buffer(bh);
281 			brelse(bh);
282 		} else {
283 			bh->b_end_io = end_buffer_read_sync;
284 			bhs[num++] = bh;
285 		}
286 	}
287 
288 	gfs2_submit_bhs(REQ_OP_READ, READ_SYNC | REQ_META | REQ_PRIO, bhs, num);
289 	if (!(flags & DIO_WAIT))
290 		return 0;
291 
292 	bh = *bhp;
293 	wait_on_buffer(bh);
294 	if (unlikely(!buffer_uptodate(bh))) {
295 		struct gfs2_trans *tr = current->journal_info;
296 		if (tr && tr->tr_touched)
297 			gfs2_io_error_bh(sdp, bh);
298 		brelse(bh);
299 		*bhp = NULL;
300 		return -EIO;
301 	}
302 
303 	return 0;
304 }
305 
306 /**
307  * gfs2_meta_wait - Reread a block from disk
308  * @sdp: the filesystem
309  * @bh: The block to wait for
310  *
311  * Returns: errno
312  */
313 
314 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
315 {
316 	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
317 		return -EIO;
318 
319 	wait_on_buffer(bh);
320 
321 	if (!buffer_uptodate(bh)) {
322 		struct gfs2_trans *tr = current->journal_info;
323 		if (tr && tr->tr_touched)
324 			gfs2_io_error_bh(sdp, bh);
325 		return -EIO;
326 	}
327 	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
328 		return -EIO;
329 
330 	return 0;
331 }
332 
333 void gfs2_remove_from_journal(struct buffer_head *bh, int meta)
334 {
335 	struct address_space *mapping = bh->b_page->mapping;
336 	struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
337 	struct gfs2_bufdata *bd = bh->b_private;
338 	struct gfs2_trans *tr = current->journal_info;
339 	int was_pinned = 0;
340 
341 	if (test_clear_buffer_pinned(bh)) {
342 		trace_gfs2_pin(bd, 0);
343 		atomic_dec(&sdp->sd_log_pinned);
344 		list_del_init(&bd->bd_list);
345 		if (meta == REMOVE_META)
346 			tr->tr_num_buf_rm++;
347 		else
348 			tr->tr_num_databuf_rm++;
349 		tr->tr_touched = 1;
350 		was_pinned = 1;
351 		brelse(bh);
352 	}
353 	if (bd) {
354 		spin_lock(&sdp->sd_ail_lock);
355 		if (bd->bd_tr) {
356 			gfs2_trans_add_revoke(sdp, bd);
357 		} else if (was_pinned) {
358 			bh->b_private = NULL;
359 			kmem_cache_free(gfs2_bufdata_cachep, bd);
360 		}
361 		spin_unlock(&sdp->sd_ail_lock);
362 	}
363 	clear_buffer_dirty(bh);
364 	clear_buffer_uptodate(bh);
365 }
366 
367 /**
368  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
369  * @ip: the inode who owns the buffers
370  * @bstart: the first buffer in the run
371  * @blen: the number of buffers in the run
372  *
373  */
374 
375 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
376 {
377 	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
378 	struct buffer_head *bh;
379 
380 	while (blen) {
381 		bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
382 		if (bh) {
383 			lock_buffer(bh);
384 			gfs2_log_lock(sdp);
385 			gfs2_remove_from_journal(bh, REMOVE_META);
386 			gfs2_log_unlock(sdp);
387 			unlock_buffer(bh);
388 			brelse(bh);
389 		}
390 
391 		bstart++;
392 		blen--;
393 	}
394 }
395 
396 /**
397  * gfs2_meta_indirect_buffer - Get a metadata buffer
398  * @ip: The GFS2 inode
399  * @height: The level of this buf in the metadata (indir addr) tree (if any)
400  * @num: The block number (device relative) of the buffer
401  * @bhp: the buffer is returned here
402  *
403  * Returns: errno
404  */
405 
406 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
407 			      struct buffer_head **bhp)
408 {
409 	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
410 	struct gfs2_glock *gl = ip->i_gl;
411 	struct buffer_head *bh;
412 	int ret = 0;
413 	u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
414 	int rahead = 0;
415 
416 	if (num == ip->i_no_addr)
417 		rahead = ip->i_rahead;
418 
419 	ret = gfs2_meta_read(gl, num, DIO_WAIT, rahead, &bh);
420 	if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
421 		brelse(bh);
422 		ret = -EIO;
423 	}
424 	*bhp = bh;
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 
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, READ_SYNC | REQ_META, 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, REQ_RAHEAD | REQ_META, 1, &bh);
466 		brelse(bh);
467 		dblock++;
468 		extlen--;
469 		if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
470 			goto out;
471 	}
472 
473 	wait_on_buffer(first_bh);
474 out:
475 	return first_bh;
476 }
477 
478