release/src-rt-6.x.4708/linux/linux-2.6.36/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         struct buffer_head *bh, *head;
  38         int nr_underway = 0;
  39         int write_op = REQ_META |
  40                 (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC_PLUG : WRITE);
  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 pdflush and kswapd
  55                  * activity, but those code paths have their own higher-level
  56                  * throttling.
  57                  */
  58                 if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
  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(write_op, 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         .sync_page = block_sync_page,
  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, 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                 atomic_dec(&sdp->sd_log_pinned);
 315                 list_del_init(&bd->bd_le.le_list);
 316                 if (meta) {
 317                         gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
 318                         sdp->sd_log_num_buf--;
 319                         tr->tr_num_buf_rm++;
 320                 } else {
 321                         gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
 322                         sdp->sd_log_num_databuf--;
 323                         tr->tr_num_databuf_rm++;
 324                 }
 325                 tr->tr_touched = 1;
 326                 brelse(bh);
 327         }
 328         if (bd) {
 329                 if (bd->bd_ail) {
 330                         gfs2_remove_from_ail(bd);
 331                         bh->b_private = NULL;
 332                         bd->bd_bh = NULL;
 333                         bd->bd_blkno = bh->b_blocknr;
 334                         gfs2_trans_add_revoke(sdp, bd);
 335                 }
 336         }
 337         clear_buffer_dirty(bh);
 338         clear_buffer_uptodate(bh);
 339 }
 340
 341 /**
 342  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 343  * @ip: the inode who owns the buffers
 344  * @bstart: the first buffer in the run
 345  * @blen: the number of buffers in the run
 346  *
 347  */
 348
 349 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
 350 {
 351         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 352         struct buffer_head *bh;
 353
 354         while (blen) {
 355                 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
 356                 if (bh) {
 357                         lock_buffer(bh);
 358                         gfs2_log_lock(sdp);
 359                         gfs2_remove_from_journal(bh, current->journal_info, 1);
 360                         gfs2_log_unlock(sdp);
 361                         unlock_buffer(bh);
 362                         brelse(bh);
 363                 }
 364
 365                 bstart++;
 366                 blen--;
 367         }
 368 }
 369
 370 /**
 371  * gfs2_meta_indirect_buffer - Get a metadata buffer
 372  * @ip: The GFS2 inode
 373  * @height: The level of this buf in the metadata (indir addr) tree (if any)
 374  * @num: The block number (device relative) of the buffer
 375  * @new: Non-zero if we may create a new buffer
 376  * @bhp: the buffer is returned here
 377  *
 378  * Returns: errno
 379  */
 380
 381 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
 382                               int new, struct buffer_head **bhp)
 383 {
 384         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 385         struct gfs2_glock *gl = ip->i_gl;
 386         struct buffer_head *bh;
 387         int ret = 0;
 388
 389         if (new) {
 390                 BUG_ON(height == 0);
 391                 bh = gfs2_meta_new(gl, num);
 392                 gfs2_trans_add_bh(ip->i_gl, bh, 1);
 393                 gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
 394                 gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
 395         } else {
 396                 u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
 397                 ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
 398                 if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
 399                         brelse(bh);
 400                         ret = -EIO;
 401                 }
 402         }
 403         *bhp = bh;
 404         return ret;
 405 }
 406
 407 /**
 408  * gfs2_meta_ra - start readahead on an extent of a file
 409  * @gl: the glock the blocks belong to
 410  * @dblock: the starting disk block
 411  * @extlen: the number of blocks in the extent
 412  *
 413  * returns: the first buffer in the extent
 414  */
 415
 416 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
 417 {
 418         struct gfs2_sbd *sdp = gl->gl_sbd;
 419         struct buffer_head *first_bh, *bh;
 420         u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
 421                           sdp->sd_sb.sb_bsize_shift;
 422
 423         BUG_ON(!extlen);
 424
 425         if (max_ra < 1)
 426                 max_ra = 1;
 427         if (extlen > max_ra)
 428                 extlen = max_ra;
 429
 430         first_bh = gfs2_getbuf(gl, dblock, CREATE);
 431
 432         if (buffer_uptodate(first_bh))
 433                 goto out;
 434         if (!buffer_locked(first_bh))
 435                 ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh);
 436
 437         dblock++;
 438         extlen--;
 439
 440         while (extlen) {
 441                 bh = gfs2_getbuf(gl, dblock, CREATE);
 442
 443                 if (!buffer_uptodate(bh) && !buffer_locked(bh))
 444                         ll_rw_block(READA, 1, &bh);
 445                 brelse(bh);
 446                 dblock++;
 447                 extlen--;
 448                 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
 449                         goto out;
 450         }
 451
 452         wait_on_buffer(first_bh);
 453 out:
 454         return first_bh;
 455 }