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 const struct address_space_operations gfs2_meta_aops = {
  97         .writepage = gfs2_aspace_writepage,
  98         .releasepage = gfs2_releasepage,
  99         .sync_page = block_sync_page,
 100 };
 101
 102 /**
 103  * gfs2_meta_sync - Sync all buffers associated with a glock
 104  * @gl: The glock
 105  *
 106  */
 107
 108 void gfs2_meta_sync(struct gfs2_glock *gl)
 109 {
 110         struct address_space *mapping = gfs2_glock2aspace(gl);
 111         int error;
 112
 113         filemap_fdatawrite(mapping);
 114         error = filemap_fdatawait(mapping);
 115
 116         if (error)
 117                 gfs2_io_error(gl->gl_sbd);
 118 }
 119
 120 /**
 121  * gfs2_getbuf - Get a buffer with a given address space
 122  * @gl: the glock
 123  * @blkno: the block number (filesystem scope)
 124  * @create: 1 if the buffer should be created
 125  *
 126  * Returns: the buffer
 127  */
 128
 129 struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
 130 {
 131         struct address_space *mapping = gfs2_glock2aspace(gl);
 132         struct gfs2_sbd *sdp = gl->gl_sbd;
 133         struct page *page;
 134         struct buffer_head *bh;
 135         unsigned int shift;
 136         unsigned long index;
 137         unsigned int bufnum;
 138
 139         shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
 140         index = blkno >> shift;             /* convert block to page */
 141         bufnum = blkno - (index << shift);  /* block buf index within page */
 142
 143         if (create) {
 144                 for (;;) {
 145                         page = grab_cache_page(mapping, index);
 146                         if (page)
 147                                 break;
 148                         yield();
 149                 }
 150         } else {
 151                 page = find_lock_page(mapping, index);
 152                 if (!page)
 153                         return NULL;
 154         }
 155
 156         if (!page_has_buffers(page))
 157                 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
 158
 159         /* Locate header for our buffer within our page */
 160         for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
 161                 /* Do nothing */;
 162         get_bh(bh);
 163
 164         if (!buffer_mapped(bh))
 165                 map_bh(bh, sdp->sd_vfs, blkno);
 166
 167         unlock_page(page);
 168         mark_page_accessed(page);
 169         page_cache_release(page);
 170
 171         return bh;
 172 }
 173
 174 static void meta_prep_new(struct buffer_head *bh)
 175 {
 176         struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
 177
 178         lock_buffer(bh);
 179         clear_buffer_dirty(bh);
 180         set_buffer_uptodate(bh);
 181         unlock_buffer(bh);
 182
 183         mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
 184 }
 185
 186 /**
 187  * gfs2_meta_new - Get a block
 188  * @gl: The glock associated with this block
 189  * @blkno: The block number
 190  *
 191  * Returns: The buffer
 192  */
 193
 194 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
 195 {
 196         struct buffer_head *bh;
 197         bh = gfs2_getbuf(gl, blkno, CREATE);
 198         meta_prep_new(bh);
 199         return bh;
 200 }
 201
 202 /**
 203  * gfs2_meta_read - Read a block from disk
 204  * @gl: The glock covering the block
 205  * @blkno: The block number
 206  * @flags: flags
 207  * @bhp: the place where the buffer is returned (NULL on failure)
 208  *
 209  * Returns: errno
 210  */
 211
 212 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
 213                    struct buffer_head **bhp)
 214 {
 215         struct gfs2_sbd *sdp = gl->gl_sbd;
 216         struct buffer_head *bh;
 217
 218         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 219                 return -EIO;
 220
 221         *bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
 222
 223         lock_buffer(bh);
 224         if (buffer_uptodate(bh)) {
 225                 unlock_buffer(bh);
 226                 return 0;
 227         }
 228         bh->b_end_io = end_buffer_read_sync;
 229         get_bh(bh);
 230         submit_bh(READ_SYNC | (1 << BIO_RW_META), bh);
 231         if (!(flags & DIO_WAIT))
 232                 return 0;
 233
 234         wait_on_buffer(bh);
 235         if (unlikely(!buffer_uptodate(bh))) {
 236                 struct gfs2_trans *tr = current->journal_info;
 237                 if (tr && tr->tr_touched)
 238                         gfs2_io_error_bh(sdp, bh);
 239                 brelse(bh);
 240                 return -EIO;
 241         }
 242
 243         return 0;
 244 }
 245
 246 /**
 247  * gfs2_meta_wait - Reread a block from disk
 248  * @sdp: the filesystem
 249  * @bh: The block to wait for
 250  *
 251  * Returns: errno
 252  */
 253
 254 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
 255 {
 256         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 257                 return -EIO;
 258
 259         wait_on_buffer(bh);
 260
 261         if (!buffer_uptodate(bh)) {
 262                 struct gfs2_trans *tr = current->journal_info;
 263                 if (tr && tr->tr_touched)
 264                         gfs2_io_error_bh(sdp, bh);
 265                 return -EIO;
 266         }
 267         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 268                 return -EIO;
 269
 270         return 0;
 271 }
 272
 273 /**
 274  * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
 275  * @gl: the glock the buffer belongs to
 276  * @bh: The buffer to be attached to
 277  * @meta: Flag to indicate whether its metadata or not
 278  */
 279
 280 void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
 281                          int meta)
 282 {
 283         struct gfs2_bufdata *bd;
 284
 285         if (meta)
 286                 lock_page(bh->b_page);
 287
 288         if (bh->b_private) {
 289                 if (meta)
 290                         unlock_page(bh->b_page);
 291                 return;
 292         }
 293
 294         bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
 295         bd->bd_bh = bh;
 296         bd->bd_gl = gl;
 297
 298         INIT_LIST_HEAD(&bd->bd_list_tr);
 299         if (meta)
 300                 lops_init_le(&bd->bd_le, &gfs2_buf_lops);
 301         else
 302                 lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
 303         bh->b_private = bd;
 304
 305         if (meta)
 306                 unlock_page(bh->b_page);
 307 }
 308
 309 void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
 310 {
 311         struct address_space *mapping = bh->b_page->mapping;
 312         struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
 313         struct gfs2_bufdata *bd = bh->b_private;
 314
 315         if (test_clear_buffer_pinned(bh)) {
 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                 if (bd->bd_ail) {
 331                         gfs2_remove_from_ail(bd);
 332                         bh->b_private = NULL;
 333                         bd->bd_bh = NULL;
 334                         bd->bd_blkno = bh->b_blocknr;
 335                         gfs2_trans_add_revoke(sdp, bd);
 336                 }
 337         }
 338         clear_buffer_dirty(bh);
 339         clear_buffer_uptodate(bh);
 340 }
 341
 342 /**
 343  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 344  * @ip: the inode who owns the buffers
 345  * @bstart: the first buffer in the run
 346  * @blen: the number of buffers in the run
 347  *
 348  */
 349
 350 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
 351 {
 352         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 353         struct buffer_head *bh;
 354
 355         while (blen) {
 356                 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
 357                 if (bh) {
 358                         lock_buffer(bh);
 359                         gfs2_log_lock(sdp);
 360                         gfs2_remove_from_journal(bh, current->journal_info, 1);
 361                         gfs2_log_unlock(sdp);
 362                         unlock_buffer(bh);
 363                         brelse(bh);
 364                 }
 365
 366                 bstart++;
 367                 blen--;
 368         }
 369 }
 370
 371 /**
 372  * gfs2_meta_indirect_buffer - Get a metadata buffer
 373  * @ip: The GFS2 inode
 374  * @height: The level of this buf in the metadata (indir addr) tree (if any)
 375  * @num: The block number (device relative) of the buffer
 376  * @new: Non-zero if we may create a new buffer
 377  * @bhp: the buffer is returned here
 378  *
 379  * Returns: errno
 380  */
 381
 382 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
 383                               int new, struct buffer_head **bhp)
 384 {
 385         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 386         struct gfs2_glock *gl = ip->i_gl;
 387         struct buffer_head *bh;
 388         int ret = 0;
 389
 390         if (new) {
 391                 BUG_ON(height == 0);
 392                 bh = gfs2_meta_new(gl, num);
 393                 gfs2_trans_add_bh(ip->i_gl, bh, 1);
 394                 gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
 395                 gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
 396         } else {
 397                 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
 398                 ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
 399                 if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
 400                         brelse(bh);
 401                         ret = -EIO;
 402                 }
 403         }
 404         *bhp = bh;
 405         return ret;
 406 }
 407
 408 /**
 409  * gfs2_meta_ra - start readahead on an extent of a file
 410  * @gl: the glock the blocks belong to
 411  * @dblock: the starting disk block
 412  * @extlen: the number of blocks in the extent
 413  *
 414  * returns: the first buffer in the extent
 415  */
 416
 417 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
 418 {
 419         struct gfs2_sbd *sdp = gl->gl_sbd;
 420         struct buffer_head *first_bh, *bh;
 421         u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
 422                           sdp->sd_sb.sb_bsize_shift;
 423
 424         BUG_ON(!extlen);
 425
 426         if (max_ra < 1)
 427                 max_ra = 1;
 428         if (extlen > max_ra)
 429                 extlen = max_ra;
 430
 431         first_bh = gfs2_getbuf(gl, dblock, CREATE);
 432
 433         if (buffer_uptodate(first_bh))
 434                 goto out;
 435         if (!buffer_locked(first_bh))
 436                 ll_rw_block(READ_SYNC | (1 << BIO_RW_META), 1, &first_bh);
 437
 438         dblock++;
 439         extlen--;
 440
 441         while (extlen) {
 442                 bh = gfs2_getbuf(gl, dblock, CREATE);
 443
 444                 if (!buffer_uptodate(bh) && !buffer_locked(bh))
 445                         ll_rw_block(READA, 1, &bh);
 446                 brelse(bh);
 447                 dblock++;
 448                 extlen--;
 449                 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
 450                         goto out;
 451         }
 452
 453         wait_on_buffer(first_bh);
 454 out:
 455         return first_bh;
 456 }
 457