block: separate priority boosting from REQ_META
[linux-2.6.git] / fs / gfs2 / meta_io.c
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_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
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
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
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
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
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
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                 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
252 int 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
278 void 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         INIT_LIST_HEAD(&bd->bd_list_tr);
297         if (meta)
298                 lops_init_le(&bd->bd_le, &gfs2_buf_lops);
299         else
300                 lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
301         bh->b_private = bd;
302
303         if (meta)
304                 unlock_page(bh->b_page);
305 }
306
307 void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
308 {
309         struct address_space *mapping = bh->b_page->mapping;
310         struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
311         struct gfs2_bufdata *bd = bh->b_private;
312
313         if (test_clear_buffer_pinned(bh)) {
314                 trace_gfs2_pin(bd, 0);
315                 atomic_dec(&sdp->sd_log_pinned);
316                 list_del_init(&bd->bd_le.le_list);
317                 if (meta) {
318                         gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
319                         sdp->sd_log_num_buf--;
320                         tr->tr_num_buf_rm++;
321                 } else {
322                         gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
323                         sdp->sd_log_num_databuf--;
324                         tr->tr_num_databuf_rm++;
325                 }
326                 tr->tr_touched = 1;
327                 brelse(bh);
328         }
329         if (bd) {
330                 spin_lock(&sdp->sd_ail_lock);
331                 if (bd->bd_ail) {
332                         gfs2_remove_from_ail(bd);
333                         bh->b_private = NULL;
334                         bd->bd_bh = NULL;
335                         bd->bd_blkno = bh->b_blocknr;
336                         gfs2_trans_add_revoke(sdp, bd);
337                 }
338                 spin_unlock(&sdp->sd_ail_lock);
339         }
340         clear_buffer_dirty(bh);
341         clear_buffer_uptodate(bh);
342 }
343
344 /**
345  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
346  * @ip: the inode who owns the buffers
347  * @bstart: the first buffer in the run
348  * @blen: the number of buffers in the run
349  *
350  */
351
352 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
353 {
354         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
355         struct buffer_head *bh;
356
357         while (blen) {
358                 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
359                 if (bh) {
360                         lock_buffer(bh);
361                         gfs2_log_lock(sdp);
362                         gfs2_remove_from_journal(bh, current->journal_info, 1);
363                         gfs2_log_unlock(sdp);
364                         unlock_buffer(bh);
365                         brelse(bh);
366                 }
367
368                 bstart++;
369                 blen--;
370         }
371 }
372
373 /**
374  * gfs2_meta_indirect_buffer - Get a metadata buffer
375  * @ip: The GFS2 inode
376  * @height: The level of this buf in the metadata (indir addr) tree (if any)
377  * @num: The block number (device relative) of the buffer
378  * @new: Non-zero if we may create a new buffer
379  * @bhp: the buffer is returned here
380  *
381  * Returns: errno
382  */
383
384 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
385                               int new, struct buffer_head **bhp)
386 {
387         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
388         struct gfs2_glock *gl = ip->i_gl;
389         struct buffer_head *bh;
390         int ret = 0;
391
392         if (new) {
393                 BUG_ON(height == 0);
394                 bh = gfs2_meta_new(gl, num);
395                 gfs2_trans_add_bh(ip->i_gl, bh, 1);
396                 gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
397                 gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
398         } else {
399                 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
400                 ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
401                 if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
402                         brelse(bh);
403                         ret = -EIO;
404                 }
405         }
406         *bhp = bh;
407         return ret;
408 }
409
410 /**
411  * gfs2_meta_ra - start readahead on an extent of a file
412  * @gl: the glock the blocks belong to
413  * @dblock: the starting disk block
414  * @extlen: the number of blocks in the extent
415  *
416  * returns: the first buffer in the extent
417  */
418
419 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
420 {
421         struct gfs2_sbd *sdp = gl->gl_sbd;
422         struct buffer_head *first_bh, *bh;
423         u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
424                           sdp->sd_sb.sb_bsize_shift;
425
426         BUG_ON(!extlen);
427
428         if (max_ra < 1)
429                 max_ra = 1;
430         if (extlen > max_ra)
431                 extlen = max_ra;
432
433         first_bh = gfs2_getbuf(gl, dblock, CREATE);
434
435         if (buffer_uptodate(first_bh))
436                 goto out;
437         if (!buffer_locked(first_bh))
438                 ll_rw_block(READ_SYNC | REQ_META | REQ_PRIO, 1, &first_bh);
439
440         dblock++;
441         extlen--;
442
443         while (extlen) {
444                 bh = gfs2_getbuf(gl, dblock, CREATE);
445
446                 if (!buffer_uptodate(bh) && !buffer_locked(bh))
447                         ll_rw_block(READA, 1, &bh);
448                 brelse(bh);
449                 dblock++;
450                 extlen--;
451                 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
452                         goto out;
453         }
454
455         wait_on_buffer(first_bh);
456 out:
457         return first_bh;
458 }
459