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_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
 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
 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
 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
 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_error);
 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  */
 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->bi_bdev = 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
 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(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
 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(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
 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
 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
 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         }
 423         *bhp = bh;
 424         return ret;
 425 }
 426
 427 /**
 428  * gfs2_meta_ra - start readahead on an extent of a file
 429  * @gl: the glock the blocks belong to
 430  * @dblock: the starting disk block
 431  * @extlen: the number of blocks in the extent
 432  *
 433  * returns: the first buffer in the extent
 434  */
 435
 436 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
 437 {
 438         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 439         struct buffer_head *first_bh, *bh;
 440         u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
 441                           sdp->sd_sb.sb_bsize_shift;
 442
 443         BUG_ON(!extlen);
 444
 445         if (max_ra < 1)
 446                 max_ra = 1;
 447         if (extlen > max_ra)
 448                 extlen = max_ra;
 449
 450         first_bh = gfs2_getbuf(gl, dblock, CREATE);
 451
 452         if (buffer_uptodate(first_bh))
 453                 goto out;
 454         if (!buffer_locked(first_bh))
 455                 ll_rw_block(REQ_OP_READ, REQ_META, 1, &first_bh);
 456
 457         dblock++;
 458         extlen--;
 459
 460         while (extlen) {
 461                 bh = gfs2_getbuf(gl, dblock, CREATE);
 462
 463                 if (!buffer_uptodate(bh) && !buffer_locked(bh))
 464                         ll_rw_block(REQ_OP_READ, REQ_RAHEAD | REQ_META, 1, &bh);
 465                 brelse(bh);
 466                 dblock++;
 467                 extlen--;
 468                 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
 469                         goto out;
 470         }
 471
 472         wait_on_buffer(first_bh);
 473 out:
 474         return first_bh;
 475 }
 476