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
  35 static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wbc)
  36 {
  37         int err;
  38         struct buffer_head *bh, *head;
  39         int nr_underway = 0;
  40         int write_op = (1 << BIO_RW_META) | ((wbc->sync_mode == WB_SYNC_ALL ?
  41                         WRITE_SYNC_PLUG : 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 || !wbc->nonblocking) {
  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         err = 0;
  90         if (nr_underway == 0)
  91                 end_page_writeback(page);
  92
  93         return err;
  94 }
  95
  96 static const struct address_space_operations aspace_aops = {
  97         .writepage = gfs2_aspace_writepage,
  98         .releasepage = gfs2_releasepage,
  99         .sync_page = block_sync_page,
 100 };
 101
 102 /**
 103  * gfs2_aspace_get - Create and initialize a struct inode structure
 104  * @sdp: the filesystem the aspace is in
 105  *
 106  * Right now a struct inode is just a struct inode.  Maybe Linux
 107  * will supply a more lightweight address space construct (that works)
 108  * in the future.
 109  *
 110  * Make sure pages/buffers in this aspace aren't in high memory.
 111  *
 112  * Returns: the aspace
 113  */
 114
 115 struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
 116 {
 117         struct inode *aspace;
 118         struct gfs2_inode *ip;
 119
 120         aspace = new_inode(sdp->sd_vfs);
 121         if (aspace) {
 122                 mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);
 123                 aspace->i_mapping->a_ops = &aspace_aops;
 124                 aspace->i_size = MAX_LFS_FILESIZE;
 125                 ip = GFS2_I(aspace);
 126                 clear_bit(GIF_USER, &ip->i_flags);
 127                 insert_inode_hash(aspace);
 128         }
 129         return aspace;
 130 }
 131
 132 void gfs2_aspace_put(struct inode *aspace)
 133 {
 134         remove_inode_hash(aspace);
 135         iput(aspace);
 136 }
 137
 138 /**
 139  * gfs2_meta_sync - Sync all buffers associated with a glock
 140  * @gl: The glock
 141  *
 142  */
 143
 144 void gfs2_meta_sync(struct gfs2_glock *gl)
 145 {
 146         struct address_space *mapping = gl->gl_aspace->i_mapping;
 147         int error;
 148
 149         filemap_fdatawrite(mapping);
 150         error = filemap_fdatawait(mapping);
 151
 152         if (error)
 153                 gfs2_io_error(gl->gl_sbd);
 154 }
 155
 156 /**
 157  * gfs2_getbuf - Get a buffer with a given address space
 158  * @gl: the glock
 159  * @blkno: the block number (filesystem scope)
 160  * @create: 1 if the buffer should be created
 161  *
 162  * Returns: the buffer
 163  */
 164
 165 struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
 166 {
 167         struct address_space *mapping = gl->gl_aspace->i_mapping;
 168         struct gfs2_sbd *sdp = gl->gl_sbd;
 169         struct page *page;
 170         struct buffer_head *bh;
 171         unsigned int shift;
 172         unsigned long index;
 173         unsigned int bufnum;
 174
 175         shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
 176         index = blkno >> shift;             /* convert block to page */
 177         bufnum = blkno - (index << shift);  /* block buf index within page */
 178
 179         if (create) {
 180                 for (;;) {
 181                         page = grab_cache_page(mapping, index);
 182                         if (page)
 183                                 break;
 184                         yield();
 185                 }
 186         } else {
 187                 page = find_lock_page(mapping, index);
 188                 if (!page)
 189                         return NULL;
 190         }
 191
 192         if (!page_has_buffers(page))
 193                 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
 194
 195         /* Locate header for our buffer within our page */
 196         for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
 197                 /* Do nothing */;
 198         get_bh(bh);
 199
 200         if (!buffer_mapped(bh))
 201                 map_bh(bh, sdp->sd_vfs, blkno);
 202
 203         unlock_page(page);
 204         mark_page_accessed(page);
 205         page_cache_release(page);
 206
 207         return bh;
 208 }
 209
 210 static void meta_prep_new(struct buffer_head *bh)
 211 {
 212         struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
 213
 214         lock_buffer(bh);
 215         clear_buffer_dirty(bh);
 216         set_buffer_uptodate(bh);
 217         unlock_buffer(bh);
 218
 219         mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
 220 }
 221
 222 /**
 223  * gfs2_meta_new - Get a block
 224  * @gl: The glock associated with this block
 225  * @blkno: The block number
 226  *
 227  * Returns: The buffer
 228  */
 229
 230 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
 231 {
 232         struct buffer_head *bh;
 233         bh = gfs2_getbuf(gl, blkno, CREATE);
 234         meta_prep_new(bh);
 235         return bh;
 236 }
 237
 238 /**
 239  * gfs2_meta_read - Read a block from disk
 240  * @gl: The glock covering the block
 241  * @blkno: The block number
 242  * @flags: flags
 243  * @bhp: the place where the buffer is returned (NULL on failure)
 244  *
 245  * Returns: errno
 246  */
 247
 248 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
 249                    struct buffer_head **bhp)
 250 {
 251         struct gfs2_sbd *sdp = gl->gl_sbd;
 252         struct buffer_head *bh;
 253
 254         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 255                 return -EIO;
 256
 257         *bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
 258
 259         lock_buffer(bh);
 260         if (buffer_uptodate(bh)) {
 261                 unlock_buffer(bh);
 262                 return 0;
 263         }
 264         bh->b_end_io = end_buffer_read_sync;
 265         get_bh(bh);
 266         submit_bh(READ_SYNC | (1 << BIO_RW_META), bh);
 267         if (!(flags & DIO_WAIT))
 268                 return 0;
 269
 270         wait_on_buffer(bh);
 271         if (unlikely(!buffer_uptodate(bh))) {
 272                 struct gfs2_trans *tr = current->journal_info;
 273                 if (tr && tr->tr_touched)
 274                         gfs2_io_error_bh(sdp, bh);
 275                 brelse(bh);
 276                 return -EIO;
 277         }
 278
 279         return 0;
 280 }
 281
 282 /**
 283  * gfs2_meta_wait - Reread a block from disk
 284  * @sdp: the filesystem
 285  * @bh: The block to wait for
 286  *
 287  * Returns: errno
 288  */
 289
 290 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
 291 {
 292         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 293                 return -EIO;
 294
 295         wait_on_buffer(bh);
 296
 297         if (!buffer_uptodate(bh)) {
 298                 struct gfs2_trans *tr = current->journal_info;
 299                 if (tr && tr->tr_touched)
 300                         gfs2_io_error_bh(sdp, bh);
 301                 return -EIO;
 302         }
 303         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 304                 return -EIO;
 305
 306         return 0;
 307 }
 308
 309 /**
 310  * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
 311  * @gl: the glock the buffer belongs to
 312  * @bh: The buffer to be attached to
 313  * @meta: Flag to indicate whether its metadata or not
 314  */
 315
 316 void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
 317                          int meta)
 318 {
 319         struct gfs2_bufdata *bd;
 320
 321         if (meta)
 322                 lock_page(bh->b_page);
 323
 324         if (bh->b_private) {
 325                 if (meta)
 326                         unlock_page(bh->b_page);
 327                 return;
 328         }
 329
 330         bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
 331         bd->bd_bh = bh;
 332         bd->bd_gl = gl;
 333
 334         INIT_LIST_HEAD(&bd->bd_list_tr);
 335         if (meta)
 336                 lops_init_le(&bd->bd_le, &gfs2_buf_lops);
 337         else
 338                 lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
 339         bh->b_private = bd;
 340
 341         if (meta)
 342                 unlock_page(bh->b_page);
 343 }
 344
 345 void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
 346 {
 347         struct gfs2_sbd *sdp = GFS2_SB(bh->b_page->mapping->host);
 348         struct gfs2_bufdata *bd = bh->b_private;
 349         if (test_clear_buffer_pinned(bh)) {
 350                 list_del_init(&bd->bd_le.le_list);
 351                 if (meta) {
 352                         gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
 353                         sdp->sd_log_num_buf--;
 354                         tr->tr_num_buf_rm++;
 355                 } else {
 356                         gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
 357                         sdp->sd_log_num_databuf--;
 358                         tr->tr_num_databuf_rm++;
 359                 }
 360                 tr->tr_touched = 1;
 361                 brelse(bh);
 362         }
 363         if (bd) {
 364                 if (bd->bd_ail) {
 365                         gfs2_remove_from_ail(bd);
 366                         bh->b_private = NULL;
 367                         bd->bd_bh = NULL;
 368                         bd->bd_blkno = bh->b_blocknr;
 369                         gfs2_trans_add_revoke(sdp, bd);
 370                 }
 371         }
 372         clear_buffer_dirty(bh);
 373         clear_buffer_uptodate(bh);
 374 }
 375
 376 /**
 377  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 378  * @ip: the inode who owns the buffers
 379  * @bstart: the first buffer in the run
 380  * @blen: the number of buffers in the run
 381  *
 382  */
 383
 384 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
 385 {
 386         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 387         struct buffer_head *bh;
 388
 389         while (blen) {
 390                 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
 391                 if (bh) {
 392                         lock_buffer(bh);
 393                         gfs2_log_lock(sdp);
 394                         gfs2_remove_from_journal(bh, current->journal_info, 1);
 395                         gfs2_log_unlock(sdp);
 396                         unlock_buffer(bh);
 397                         brelse(bh);
 398                 }
 399
 400                 bstart++;
 401                 blen--;
 402         }
 403 }
 404
 405 /**
 406  * gfs2_meta_indirect_buffer - Get a metadata buffer
 407  * @ip: The GFS2 inode
 408  * @height: The level of this buf in the metadata (indir addr) tree (if any)
 409  * @num: The block number (device relative) of the buffer
 410  * @new: Non-zero if we may create a new buffer
 411  * @bhp: the buffer is returned here
 412  *
 413  * Returns: errno
 414  */
 415
 416 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
 417                               int new, struct buffer_head **bhp)
 418 {
 419         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 420         struct gfs2_glock *gl = ip->i_gl;
 421         struct buffer_head *bh;
 422         int ret = 0;
 423
 424         if (new) {
 425                 BUG_ON(height == 0);
 426                 bh = gfs2_meta_new(gl, num);
 427                 gfs2_trans_add_bh(ip->i_gl, bh, 1);
 428                 gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
 429                 gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
 430         } else {
 431                 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
 432                 ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
 433                 if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
 434                         brelse(bh);
 435                         ret = -EIO;
 436                 }
 437         }
 438         *bhp = bh;
 439         return ret;
 440 }
 441
 442 /**
 443  * gfs2_meta_ra - start readahead on an extent of a file
 444  * @gl: the glock the blocks belong to
 445  * @dblock: the starting disk block
 446  * @extlen: the number of blocks in the extent
 447  *
 448  * returns: the first buffer in the extent
 449  */
 450
 451 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
 452 {
 453         struct gfs2_sbd *sdp = gl->gl_sbd;
 454         struct buffer_head *first_bh, *bh;
 455         u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
 456                           sdp->sd_sb.sb_bsize_shift;
 457
 458         BUG_ON(!extlen);
 459
 460         if (max_ra < 1)
 461                 max_ra = 1;
 462         if (extlen > max_ra)
 463                 extlen = max_ra;
 464
 465         first_bh = gfs2_getbuf(gl, dblock, CREATE);
 466
 467         if (buffer_uptodate(first_bh))
 468                 goto out;
 469         if (!buffer_locked(first_bh))
 470                 ll_rw_block(READ_SYNC | (1 << BIO_RW_META), 1, &first_bh);
 471
 472         dblock++;
 473         extlen--;
 474
 475         while (extlen) {
 476                 bh = gfs2_getbuf(gl, dblock, CREATE);
 477
 478                 if (!buffer_uptodate(bh) && !buffer_locked(bh))
 479                         ll_rw_block(READA, 1, &bh);
 480                 brelse(bh);
 481                 dblock++;
 482                 extlen--;
 483                 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
 484                         goto out;
 485         }
 486
 487         wait_on_buffer(first_bh);
 488 out:
 489         return first_bh;
 490 }
 491