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_op = REQ_META | REQ_PRIO |
  41                 (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : 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 flusher thread and kswapd
  56                  * activity, but those code paths have their own higher-level
  57                  * throttling.
  58                  */
  59                 if (wbc->sync_mode != WB_SYNC_NONE) {
  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         if (nr_underway == 0)
  90                 end_page_writeback(page);
  91
  92         return 0;
  93 }
  94
  95 const struct address_space_operations gfs2_meta_aops = {
  96         .writepage = gfs2_aspace_writepage,
  97         .releasepage = gfs2_releasepage,
  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                 *bhp = NULL;
 218                 return -EIO;
 219         }
 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 | REQ_META | REQ_PRIO, 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                 *bhp = NULL;
 241                 return -EIO;
 242         }
 243
 244         return 0;
 245 }
 246
 247 /**
 248  * gfs2_meta_wait - Reread a block from disk
 249  * @sdp: the filesystem
 250  * @bh: The block to wait for
 251  *
 252  * Returns: errno
 253  */
 254
 255 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
 256 {
 257         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 258                 return -EIO;
 259
 260         wait_on_buffer(bh);
 261
 262         if (!buffer_uptodate(bh)) {
 263                 struct gfs2_trans *tr = current->journal_info;
 264                 if (tr && tr->tr_touched)
 265                         gfs2_io_error_bh(sdp, bh);
 266                 return -EIO;
 267         }
 268         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 269                 return -EIO;
 270
 271         return 0;
 272 }
 273
 274 /**
 275  * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
 276  * @gl: the glock the buffer belongs to
 277  * @bh: The buffer to be attached to
 278  * @meta: Flag to indicate whether its metadata or not
 279  */
 280
 281 void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
 282                          int meta)
 283 {
 284         struct gfs2_bufdata *bd;
 285
 286         if (meta)
 287                 lock_page(bh->b_page);
 288
 289         if (bh->b_private) {
 290                 if (meta)
 291                         unlock_page(bh->b_page);
 292                 return;
 293         }
 294
 295         bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
 296         bd->bd_bh = bh;
 297         bd->bd_gl = gl;
 298
 299         if (meta)
 300                 lops_init_le(bd, &gfs2_buf_lops);
 301         else
 302                 lops_init_le(bd, &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                 trace_gfs2_pin(bd, 0);
 317                 atomic_dec(&sdp->sd_log_pinned);
 318                 list_del_init(&bd->bd_list);
 319                 if (meta) {
 320                         gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
 321                         sdp->sd_log_num_buf--;
 322                         tr->tr_num_buf_rm++;
 323                 } else {
 324                         gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
 325                         sdp->sd_log_num_databuf--;
 326                         tr->tr_num_databuf_rm++;
 327                 }
 328                 tr->tr_touched = 1;
 329                 brelse(bh);
 330         }
 331         if (bd) {
 332                 spin_lock(&sdp->sd_ail_lock);
 333                 if (bd->bd_ail) {
 334                         gfs2_remove_from_ail(bd);
 335                         bh->b_private = NULL;
 336                         bd->bd_bh = NULL;
 337                         bd->bd_blkno = bh->b_blocknr;
 338                         gfs2_trans_add_revoke(sdp, bd);
 339                 }
 340                 spin_unlock(&sdp->sd_ail_lock);
 341         }
 342         clear_buffer_dirty(bh);
 343         clear_buffer_uptodate(bh);
 344 }
 345
 346 /**
 347  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 348  * @ip: the inode who owns the buffers
 349  * @bstart: the first buffer in the run
 350  * @blen: the number of buffers in the run
 351  *
 352  */
 353
 354 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
 355 {
 356         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 357         struct buffer_head *bh;
 358
 359         while (blen) {
 360                 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
 361                 if (bh) {
 362                         lock_buffer(bh);
 363                         gfs2_log_lock(sdp);
 364                         gfs2_remove_from_journal(bh, current->journal_info, 1);
 365                         gfs2_log_unlock(sdp);
 366                         unlock_buffer(bh);
 367                         brelse(bh);
 368                 }
 369
 370                 bstart++;
 371                 blen--;
 372         }
 373 }
 374
 375 /**
 376  * gfs2_meta_indirect_buffer - Get a metadata buffer
 377  * @ip: The GFS2 inode
 378  * @height: The level of this buf in the metadata (indir addr) tree (if any)
 379  * @num: The block number (device relative) of the buffer
 380  * @bhp: the buffer is returned here
 381  *
 382  * Returns: errno
 383  */
 384
 385 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
 386                               struct buffer_head **bhp)
 387 {
 388         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 389         struct gfs2_glock *gl = ip->i_gl;
 390         struct buffer_head *bh;
 391         int ret = 0;
 392         u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
 393
 394         ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
 395         if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
 396                 brelse(bh);
 397                 ret = -EIO;
 398         }
 399         *bhp = bh;
 400         return ret;
 401 }
 402
 403 /**
 404  * gfs2_meta_ra - start readahead on an extent of a file
 405  * @gl: the glock the blocks belong to
 406  * @dblock: the starting disk block
 407  * @extlen: the number of blocks in the extent
 408  *
 409  * returns: the first buffer in the extent
 410  */
 411
 412 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
 413 {
 414         struct gfs2_sbd *sdp = gl->gl_sbd;
 415         struct buffer_head *first_bh, *bh;
 416         u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
 417                           sdp->sd_sb.sb_bsize_shift;
 418
 419         BUG_ON(!extlen);
 420
 421         if (max_ra < 1)
 422                 max_ra = 1;
 423         if (extlen > max_ra)
 424                 extlen = max_ra;
 425
 426         first_bh = gfs2_getbuf(gl, dblock, CREATE);
 427
 428         if (buffer_uptodate(first_bh))
 429                 goto out;
 430         if (!buffer_locked(first_bh))
 431                 ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh);
 432
 433         dblock++;
 434         extlen--;
 435
 436         while (extlen) {
 437                 bh = gfs2_getbuf(gl, dblock, CREATE);
 438
 439                 if (!buffer_uptodate(bh) && !buffer_locked(bh))
 440                         ll_rw_block(READA | REQ_META, 1, &bh);
 441                 brelse(bh);
 442                 dblock++;
 443                 extlen--;
 444                 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
 445                         goto out;
 446         }
 447
 448         wait_on_buffer(first_bh);
 449 out:
 450         return first_bh;
 451 }
 452