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_getbuf - Get a buffer with a given address space
 102  * @gl: the glock
 103  * @blkno: the block number (filesystem scope)
 104  * @create: 1 if the buffer should be created
 105  *
 106  * Returns: the buffer
 107  */
 108
 109 struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
 110 {
 111         struct address_space *mapping = gfs2_glock2aspace(gl);
 112         struct gfs2_sbd *sdp = gl->gl_sbd;
 113         struct page *page;
 114         struct buffer_head *bh;
 115         unsigned int shift;
 116         unsigned long index;
 117         unsigned int bufnum;
 118
 119         shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
 120         index = blkno >> shift;             /* convert block to page */
 121         bufnum = blkno - (index << shift);  /* block buf index within page */
 122
 123         if (create) {
 124                 for (;;) {
 125                         page = grab_cache_page(mapping, index);
 126                         if (page)
 127                                 break;
 128                         yield();
 129                 }
 130         } else {
 131                 page = find_lock_page(mapping, index);
 132                 if (!page)
 133                         return NULL;
 134         }
 135
 136         if (!page_has_buffers(page))
 137                 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
 138
 139         /* Locate header for our buffer within our page */
 140         for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
 141                 /* Do nothing */;
 142         get_bh(bh);
 143
 144         if (!buffer_mapped(bh))
 145                 map_bh(bh, sdp->sd_vfs, blkno);
 146
 147         unlock_page(page);
 148         mark_page_accessed(page);
 149         page_cache_release(page);
 150
 151         return bh;
 152 }
 153
 154 static void meta_prep_new(struct buffer_head *bh)
 155 {
 156         struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
 157
 158         lock_buffer(bh);
 159         clear_buffer_dirty(bh);
 160         set_buffer_uptodate(bh);
 161         unlock_buffer(bh);
 162
 163         mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
 164 }
 165
 166 /**
 167  * gfs2_meta_new - Get a block
 168  * @gl: The glock associated with this block
 169  * @blkno: The block number
 170  *
 171  * Returns: The buffer
 172  */
 173
 174 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
 175 {
 176         struct buffer_head *bh;
 177         bh = gfs2_getbuf(gl, blkno, CREATE);
 178         meta_prep_new(bh);
 179         return bh;
 180 }
 181
 182 /**
 183  * gfs2_meta_read - Read a block from disk
 184  * @gl: The glock covering the block
 185  * @blkno: The block number
 186  * @flags: flags
 187  * @bhp: the place where the buffer is returned (NULL on failure)
 188  *
 189  * Returns: errno
 190  */
 191
 192 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
 193                    struct buffer_head **bhp)
 194 {
 195         struct gfs2_sbd *sdp = gl->gl_sbd;
 196         struct buffer_head *bh;
 197
 198         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
 199                 *bhp = NULL;
 200                 return -EIO;
 201         }
 202
 203         *bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
 204
 205         lock_buffer(bh);
 206         if (buffer_uptodate(bh)) {
 207                 unlock_buffer(bh);
 208                 return 0;
 209         }
 210         bh->b_end_io = end_buffer_read_sync;
 211         get_bh(bh);
 212         submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh);
 213         if (!(flags & DIO_WAIT))
 214                 return 0;
 215
 216         wait_on_buffer(bh);
 217         if (unlikely(!buffer_uptodate(bh))) {
 218                 struct gfs2_trans *tr = current->journal_info;
 219                 if (tr && tr->tr_touched)
 220                         gfs2_io_error_bh(sdp, bh);
 221                 brelse(bh);
 222                 *bhp = NULL;
 223                 return -EIO;
 224         }
 225
 226         return 0;
 227 }
 228
 229 /**
 230  * gfs2_meta_wait - Reread a block from disk
 231  * @sdp: the filesystem
 232  * @bh: The block to wait for
 233  *
 234  * Returns: errno
 235  */
 236
 237 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
 238 {
 239         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 240                 return -EIO;
 241
 242         wait_on_buffer(bh);
 243
 244         if (!buffer_uptodate(bh)) {
 245                 struct gfs2_trans *tr = current->journal_info;
 246                 if (tr && tr->tr_touched)
 247                         gfs2_io_error_bh(sdp, bh);
 248                 return -EIO;
 249         }
 250         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 251                 return -EIO;
 252
 253         return 0;
 254 }
 255
 256 void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
 257 {
 258         struct address_space *mapping = bh->b_page->mapping;
 259         struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
 260         struct gfs2_bufdata *bd = bh->b_private;
 261         int was_pinned = 0;
 262
 263         if (test_clear_buffer_pinned(bh)) {
 264                 trace_gfs2_pin(bd, 0);
 265                 atomic_dec(&sdp->sd_log_pinned);
 266                 list_del_init(&bd->bd_list);
 267                 if (meta) {
 268                         gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
 269                         sdp->sd_log_num_buf--;
 270                         tr->tr_num_buf_rm++;
 271                 } else {
 272                         gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
 273                         sdp->sd_log_num_databuf--;
 274                         tr->tr_num_databuf_rm++;
 275                 }
 276                 tr->tr_touched = 1;
 277                 was_pinned = 1;
 278                 brelse(bh);
 279         }
 280         if (bd) {
 281                 spin_lock(&sdp->sd_ail_lock);
 282                 if (bd->bd_tr) {
 283                         gfs2_trans_add_revoke(sdp, bd);
 284                 } else if (was_pinned) {
 285                         bh->b_private = NULL;
 286                         kmem_cache_free(gfs2_bufdata_cachep, bd);
 287                 }
 288                 spin_unlock(&sdp->sd_ail_lock);
 289         }
 290         clear_buffer_dirty(bh);
 291         clear_buffer_uptodate(bh);
 292 }
 293
 294 /**
 295  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 296  * @ip: the inode who owns the buffers
 297  * @bstart: the first buffer in the run
 298  * @blen: the number of buffers in the run
 299  *
 300  */
 301
 302 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
 303 {
 304         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 305         struct buffer_head *bh;
 306
 307         while (blen) {
 308                 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
 309                 if (bh) {
 310                         lock_buffer(bh);
 311                         gfs2_log_lock(sdp);
 312                         gfs2_remove_from_journal(bh, current->journal_info, 1);
 313                         gfs2_log_unlock(sdp);
 314                         unlock_buffer(bh);
 315                         brelse(bh);
 316                 }
 317
 318                 bstart++;
 319                 blen--;
 320         }
 321 }
 322
 323 /**
 324  * gfs2_meta_indirect_buffer - Get a metadata buffer
 325  * @ip: The GFS2 inode
 326  * @height: The level of this buf in the metadata (indir addr) tree (if any)
 327  * @num: The block number (device relative) of the buffer
 328  * @bhp: the buffer is returned here
 329  *
 330  * Returns: errno
 331  */
 332
 333 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
 334                               struct buffer_head **bhp)
 335 {
 336         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 337         struct gfs2_glock *gl = ip->i_gl;
 338         struct buffer_head *bh;
 339         int ret = 0;
 340         u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
 341
 342         ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
 343         if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
 344                 brelse(bh);
 345                 ret = -EIO;
 346         }
 347         *bhp = bh;
 348         return ret;
 349 }
 350
 351 /**
 352  * gfs2_meta_ra - start readahead on an extent of a file
 353  * @gl: the glock the blocks belong to
 354  * @dblock: the starting disk block
 355  * @extlen: the number of blocks in the extent
 356  *
 357  * returns: the first buffer in the extent
 358  */
 359
 360 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
 361 {
 362         struct gfs2_sbd *sdp = gl->gl_sbd;
 363         struct buffer_head *first_bh, *bh;
 364         u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
 365                           sdp->sd_sb.sb_bsize_shift;
 366
 367         BUG_ON(!extlen);
 368
 369         if (max_ra < 1)
 370                 max_ra = 1;
 371         if (extlen > max_ra)
 372                 extlen = max_ra;
 373
 374         first_bh = gfs2_getbuf(gl, dblock, CREATE);
 375
 376         if (buffer_uptodate(first_bh))
 377                 goto out;
 378         if (!buffer_locked(first_bh))
 379                 ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh);
 380
 381         dblock++;
 382         extlen--;
 383
 384         while (extlen) {
 385                 bh = gfs2_getbuf(gl, dblock, CREATE);
 386
 387                 if (!buffer_uptodate(bh) && !buffer_locked(bh))
 388                         ll_rw_block(READA | REQ_META, 1, &bh);
 389                 brelse(bh);
 390                 dblock++;
 391                 extlen--;
 392                 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
 393                         goto out;
 394         }
 395
 396         wait_on_buffer(first_bh);
 397 out:
 398         return first_bh;
 399 }
 400