linux/fs/gfs2/meta_io.c
<<
>>
Prefs
   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
  36static 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
  95const 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
 106void 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
 127struct 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
 172static 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
 192struct 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
 210int 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
 255int 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
 281void 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
 309void 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
 354void 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
 385int 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
 412struct 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);
 449out:
 450        return first_bh;
 451}
 452
 453
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.