fs/gfs2/meta_io.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2006 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 #include <linux/lm_interface.h>
  23
  24 #include "gfs2.h"
  25 #include "incore.h"
  26 #include "glock.h"
  27 #include "glops.h"
  28 #include "inode.h"
  29 #include "log.h"
  30 #include "lops.h"
  31 #include "meta_io.h"
  32 #include "rgrp.h"
  33 #include "trans.h"
  34 #include "util.h"
  35 #include "ops_address.h"
  36
  37 static int aspace_get_block(struct inode *inode, sector_t lblock,
  38                             struct buffer_head *bh_result, int create)
  39 {
  40         gfs2_assert_warn(inode->i_sb->s_fs_info, 0);
  41         return -EOPNOTSUPP;
  42 }
  43
  44 static int gfs2_aspace_writepage(struct page *page,
  45                                  struct writeback_control *wbc)
  46 {
  47         return block_write_full_page(page, aspace_get_block, wbc);
  48 }
  49
  50 static const struct address_space_operations aspace_aops = {
  51         .writepage = gfs2_aspace_writepage,
  52         .releasepage = gfs2_releasepage,
  53 };
  54
  55 /**
  56  * gfs2_aspace_get - Create and initialize a struct inode structure
  57  * @sdp: the filesystem the aspace is in
  58  *
  59  * Right now a struct inode is just a struct inode.  Maybe Linux
  60  * will supply a more lightweight address space construct (that works)
  61  * in the future.
  62  *
  63  * Make sure pages/buffers in this aspace aren't in high memory.
  64  *
  65  * Returns: the aspace
  66  */
  67
  68 struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
  69 {
  70         struct inode *aspace;
  71
  72         aspace = new_inode(sdp->sd_vfs);
  73         if (aspace) {
  74                 mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);
  75                 aspace->i_mapping->a_ops = &aspace_aops;
  76                 aspace->i_size = ~0ULL;
  77                 aspace->i_private = NULL;
  78                 insert_inode_hash(aspace);
  79         }
  80         return aspace;
  81 }
  82
  83 void gfs2_aspace_put(struct inode *aspace)
  84 {
  85         remove_inode_hash(aspace);
  86         iput(aspace);
  87 }
  88
  89 /**
  90  * gfs2_meta_inval - Invalidate all buffers associated with a glock
  91  * @gl: the glock
  92  *
  93  */
  94
  95 void gfs2_meta_inval(struct gfs2_glock *gl)
  96 {
  97         struct gfs2_sbd *sdp = gl->gl_sbd;
  98         struct inode *aspace = gl->gl_aspace;
  99         struct address_space *mapping = gl->gl_aspace->i_mapping;
 100
 101         gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
 102
 103         atomic_inc(&aspace->i_writecount);
 104         truncate_inode_pages(mapping, 0);
 105         atomic_dec(&aspace->i_writecount);
 106
 107         gfs2_assert_withdraw(sdp, !mapping->nrpages);
 108 }
 109
 110 /**
 111  * gfs2_meta_sync - Sync all buffers associated with a glock
 112  * @gl: The glock
 113  *
 114  */
 115
 116 void gfs2_meta_sync(struct gfs2_glock *gl)
 117 {
 118         struct address_space *mapping = gl->gl_aspace->i_mapping;
 119         int error;
 120
 121         filemap_fdatawrite(mapping);
 122         error = filemap_fdatawait(mapping);
 123
 124         if (error)
 125                 gfs2_io_error(gl->gl_sbd);
 126 }
 127
 128 /**
 129  * getbuf - Get a buffer with a given address space
 130  * @gl: the glock
 131  * @blkno: the block number (filesystem scope)
 132  * @create: 1 if the buffer should be created
 133  *
 134  * Returns: the buffer
 135  */
 136
 137 static struct buffer_head *getbuf(struct gfs2_glock *gl, u64 blkno, int create)
 138 {
 139         struct address_space *mapping = gl->gl_aspace->i_mapping;
 140         struct gfs2_sbd *sdp = gl->gl_sbd;
 141         struct page *page;
 142         struct buffer_head *bh;
 143         unsigned int shift;
 144         unsigned long index;
 145         unsigned int bufnum;
 146
 147         shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
 148         index = blkno >> shift;             /* convert block to page */
 149         bufnum = blkno - (index << shift);  /* block buf index within page */
 150
 151         if (create) {
 152                 for (;;) {
 153                         page = grab_cache_page(mapping, index);
 154                         if (page)
 155                                 break;
 156                         yield();
 157                 }
 158         } else {
 159                 page = find_lock_page(mapping, index);
 160                 if (!page)
 161                         return NULL;
 162         }
 163
 164         if (!page_has_buffers(page))
 165                 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
 166
 167         /* Locate header for our buffer within our page */
 168         for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
 169                 /* Do nothing */;
 170         get_bh(bh);
 171
 172         if (!buffer_mapped(bh))
 173                 map_bh(bh, sdp->sd_vfs, blkno);
 174
 175         unlock_page(page);
 176         mark_page_accessed(page);
 177         page_cache_release(page);
 178
 179         return bh;
 180 }
 181
 182 static void meta_prep_new(struct buffer_head *bh)
 183 {
 184         struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
 185
 186         lock_buffer(bh);
 187         clear_buffer_dirty(bh);
 188         set_buffer_uptodate(bh);
 189         unlock_buffer(bh);
 190
 191         mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
 192 }
 193
 194 /**
 195  * gfs2_meta_new - Get a block
 196  * @gl: The glock associated with this block
 197  * @blkno: The block number
 198  *
 199  * Returns: The buffer
 200  */
 201
 202 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
 203 {
 204         struct buffer_head *bh;
 205         bh = getbuf(gl, blkno, CREATE);
 206         meta_prep_new(bh);
 207         return bh;
 208 }
 209
 210 /**
 211  * gfs2_meta_read - Read a block from disk
 212  * @gl: The glock covering the block
 213  * @blkno: The block number
 214  * @flags: flags
 215  * @bhp: the place where the buffer is returned (NULL on failure)
 216  *
 217  * Returns: errno
 218  */
 219
 220 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
 221                    struct buffer_head **bhp)
 222 {
 223         *bhp = getbuf(gl, blkno, CREATE);
 224         if (!buffer_uptodate(*bhp))
 225                 ll_rw_block(READ_META, 1, bhp);
 226         if (flags & DIO_WAIT) {
 227                 int error = gfs2_meta_wait(gl->gl_sbd, *bhp);
 228                 if (error) {
 229                         brelse(*bhp);
 230                         return error;
 231                 }
 232         }
 233
 234         return 0;
 235 }
 236
 237 /**
 238  * gfs2_meta_wait - Reread a block from disk
 239  * @sdp: the filesystem
 240  * @bh: The block to wait for
 241  *
 242  * Returns: errno
 243  */
 244
 245 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
 246 {
 247         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 248                 return -EIO;
 249
 250         wait_on_buffer(bh);
 251
 252         if (!buffer_uptodate(bh)) {
 253                 struct gfs2_trans *tr = current->journal_info;
 254                 if (tr && tr->tr_touched)
 255                         gfs2_io_error_bh(sdp, bh);
 256                 return -EIO;
 257         }
 258         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 259                 return -EIO;
 260
 261         return 0;
 262 }
 263
 264 /**
 265  * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
 266  * @gl: the glock the buffer belongs to
 267  * @bh: The buffer to be attached to
 268  * @meta: Flag to indicate whether its metadata or not
 269  */
 270
 271 void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
 272                          int meta)
 273 {
 274         struct gfs2_bufdata *bd;
 275
 276         if (meta)
 277                 lock_page(bh->b_page);
 278
 279         if (bh->b_private) {
 280                 if (meta)
 281                         unlock_page(bh->b_page);
 282                 return;
 283         }
 284
 285         bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL),
 286         bd->bd_bh = bh;
 287         bd->bd_gl = gl;
 288
 289         INIT_LIST_HEAD(&bd->bd_list_tr);
 290         if (meta)
 291                 lops_init_le(&bd->bd_le, &gfs2_buf_lops);
 292         else
 293                 lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
 294         bh->b_private = bd;
 295
 296         if (meta)
 297                 unlock_page(bh->b_page);
 298 }
 299
 300 /**
 301  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 302  * @ip: the inode who owns the buffers
 303  * @bstart: the first buffer in the run
 304  * @blen: the number of buffers in the run
 305  *
 306  */
 307
 308 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
 309 {
 310         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 311         struct buffer_head *bh;
 312
 313         while (blen) {
 314                 bh = getbuf(ip->i_gl, bstart, NO_CREATE);
 315                 if (bh) {
 316                         struct gfs2_bufdata *bd = bh->b_private;
 317
 318                         if (test_clear_buffer_pinned(bh)) {
 319                                 struct gfs2_trans *tr = current->journal_info;
 320                                 struct gfs2_inode *bh_ip =
 321                                         GFS2_I(bh->b_page->mapping->host);
 322
 323                                 gfs2_log_lock(sdp);
 324                                 list_del_init(&bd->bd_le.le_list);
 325                                 gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
 326                                 sdp->sd_log_num_buf--;
 327                                 gfs2_log_unlock(sdp);
 328                                 if (bh_ip->i_inode.i_private != NULL)
 329                                         tr->tr_num_databuf_rm++;
 330                                 else
 331                                         tr->tr_num_buf_rm++;
 332                                 brelse(bh);
 333                         }
 334                         if (bd) {
 335                                 gfs2_log_lock(sdp);
 336                                 if (bd->bd_ail) {
 337                                         u64 blkno = bh->b_blocknr;
 338                                         bd->bd_ail = NULL;
 339                                         list_del(&bd->bd_ail_st_list);
 340                                         list_del(&bd->bd_ail_gl_list);
 341                                         atomic_dec(&bd->bd_gl->gl_ail_count);
 342                                         brelse(bh);
 343                                         gfs2_log_unlock(sdp);
 344                                         gfs2_trans_add_revoke(sdp, blkno);
 345                                 } else
 346                                         gfs2_log_unlock(sdp);
 347                         }
 348
 349                         lock_buffer(bh);
 350                         clear_buffer_dirty(bh);
 351                         clear_buffer_uptodate(bh);
 352                         unlock_buffer(bh);
 353
 354                         brelse(bh);
 355                 }
 356
 357                 bstart++;
 358                 blen--;
 359         }
 360 }
 361
 362 /**
 363  * gfs2_meta_cache_flush - get rid of any references on buffers for this inode
 364  * @ip: The GFS2 inode
 365  *
 366  * This releases buffers that are in the most-recently-used array of
 367  * blocks used for indirect block addressing for this inode.
 368  */
 369
 370 void gfs2_meta_cache_flush(struct gfs2_inode *ip)
 371 {
 372         struct buffer_head **bh_slot;
 373         unsigned int x;
 374
 375         spin_lock(&ip->i_spin);
 376
 377         for (x = 0; x < GFS2_MAX_META_HEIGHT; x++) {
 378                 bh_slot = &ip->i_cache[x];
 379                 if (!*bh_slot)
 380                         break;
 381                 brelse(*bh_slot);
 382                 *bh_slot = NULL;
 383         }
 384
 385         spin_unlock(&ip->i_spin);
 386 }
 387
 388 /**
 389  * gfs2_meta_indirect_buffer - Get a metadata buffer
 390  * @ip: The GFS2 inode
 391  * @height: The level of this buf in the metadata (indir addr) tree (if any)
 392  * @num: The block number (device relative) of the buffer
 393  * @new: Non-zero if we may create a new buffer
 394  * @bhp: the buffer is returned here
 395  *
 396  * Try to use the gfs2_inode's MRU metadata tree cache.
 397  *
 398  * Returns: errno
 399  */
 400
 401 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
 402                               int new, struct buffer_head **bhp)
 403 {
 404         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 405         struct gfs2_glock *gl = ip->i_gl;
 406         struct buffer_head *bh = NULL, **bh_slot = ip->i_cache + height;
 407         int in_cache = 0;
 408
 409         BUG_ON(!gl);
 410         BUG_ON(!sdp);
 411
 412         spin_lock(&ip->i_spin);
 413         if (*bh_slot && (*bh_slot)->b_blocknr == num) {
 414                 bh = *bh_slot;
 415                 get_bh(bh);
 416                 in_cache = 1;
 417         }
 418         spin_unlock(&ip->i_spin);
 419
 420         if (!bh)
 421                 bh = getbuf(gl, num, CREATE);
 422
 423         if (!bh)
 424                 return -ENOBUFS;
 425
 426         if (new) {
 427                 if (gfs2_assert_warn(sdp, height))
 428                         goto err;
 429                 meta_prep_new(bh);
 430                 gfs2_trans_add_bh(ip->i_gl, bh, 1);
 431                 gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
 432                 gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
 433         } else {
 434                 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
 435                 if (!buffer_uptodate(bh)) {
 436                         ll_rw_block(READ_META, 1, &bh);
 437                         if (gfs2_meta_wait(sdp, bh))
 438                                 goto err;
 439                 }
 440                 if (gfs2_metatype_check(sdp, bh, mtype))
 441                         goto err;
 442         }
 443
 444         if (!in_cache) {
 445                 spin_lock(&ip->i_spin);
 446                 if (*bh_slot)
 447                         brelse(*bh_slot);
 448                 *bh_slot = bh;
 449                 get_bh(bh);
 450                 spin_unlock(&ip->i_spin);
 451         }
 452
 453         *bhp = bh;
 454         return 0;
 455 err:
 456         brelse(bh);
 457         return -EIO;
 458 }
 459
 460 /**
 461  * gfs2_meta_ra - start readahead on an extent of a file
 462  * @gl: the glock the blocks belong to
 463  * @dblock: the starting disk block
 464  * @extlen: the number of blocks in the extent
 465  *
 466  * returns: the first buffer in the extent
 467  */
 468
 469 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
 470 {
 471         struct gfs2_sbd *sdp = gl->gl_sbd;
 472         struct buffer_head *first_bh, *bh;
 473         u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
 474                           sdp->sd_sb.sb_bsize_shift;
 475
 476         BUG_ON(!extlen);
 477
 478         if (max_ra < 1)
 479                 max_ra = 1;
 480         if (extlen > max_ra)
 481                 extlen = max_ra;
 482
 483         first_bh = getbuf(gl, dblock, CREATE);
 484
 485         if (buffer_uptodate(first_bh))
 486                 goto out;
 487         if (!buffer_locked(first_bh))
 488                 ll_rw_block(READ_META, 1, &first_bh);
 489
 490         dblock++;
 491         extlen--;
 492
 493         while (extlen) {
 494                 bh = getbuf(gl, dblock, CREATE);
 495
 496                 if (!buffer_uptodate(bh) && !buffer_locked(bh))
 497                         ll_rw_block(READA, 1, &bh);
 498                 brelse(bh);
 499                 dblock++;
 500                 extlen--;
 501                 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
 502                         goto out;
 503         }
 504
 505         wait_on_buffer(first_bh);
 506 out:
 507         return first_bh;
 508 }
 509