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 const struct address_space_operations gfs2_rgrp_aops = {
 101         .writepage = gfs2_aspace_writepage,
 102         .releasepage = gfs2_releasepage,
 103 };
 104
 105 /**
 106  * gfs2_getbuf - Get a buffer with a given address space
 107  * @gl: the glock
 108  * @blkno: the block number (filesystem scope)
 109  * @create: 1 if the buffer should be created
 110  *
 111  * Returns: the buffer
 112  */
 113
 114 struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
 115 {
 116         struct address_space *mapping = gfs2_glock2aspace(gl);
 117         struct gfs2_sbd *sdp = gl->gl_sbd;
 118         struct page *page;
 119         struct buffer_head *bh;
 120         unsigned int shift;
 121         unsigned long index;
 122         unsigned int bufnum;
 123
 124         if (mapping == NULL)
 125                 mapping = &sdp->sd_aspace;
 126
 127         shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
 128         index = blkno >> shift;             /* convert block to page */
 129         bufnum = blkno - (index << shift);  /* block buf index within page */
 130
 131         if (create) {
 132                 for (;;) {
 133                         page = grab_cache_page(mapping, index);
 134                         if (page)
 135                                 break;
 136                         yield();
 137                 }
 138         } else {
 139                 page = find_get_page_flags(mapping, index,
 140                                                 FGP_LOCK|FGP_ACCESSED);
 141                 if (!page)
 142                         return NULL;
 143         }
 144
 145         if (!page_has_buffers(page))
 146                 create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
 147
 148         /* Locate header for our buffer within our page */
 149         for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
 150                 /* Do nothing */;
 151         get_bh(bh);
 152
 153         if (!buffer_mapped(bh))
 154                 map_bh(bh, sdp->sd_vfs, blkno);
 155
 156         unlock_page(page);
 157         page_cache_release(page);
 158
 159         return bh;
 160 }
 161
 162 static void meta_prep_new(struct buffer_head *bh)
 163 {
 164         struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
 165
 166         lock_buffer(bh);
 167         clear_buffer_dirty(bh);
 168         set_buffer_uptodate(bh);
 169         unlock_buffer(bh);
 170
 171         mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
 172 }
 173
 174 /**
 175  * gfs2_meta_new - Get a block
 176  * @gl: The glock associated with this block
 177  * @blkno: The block number
 178  *
 179  * Returns: The buffer
 180  */
 181
 182 struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
 183 {
 184         struct buffer_head *bh;
 185         bh = gfs2_getbuf(gl, blkno, CREATE);
 186         meta_prep_new(bh);
 187         return bh;
 188 }
 189
 190 /**
 191  * gfs2_meta_read - Read a block from disk
 192  * @gl: The glock covering the block
 193  * @blkno: The block number
 194  * @flags: flags
 195  * @bhp: the place where the buffer is returned (NULL on failure)
 196  *
 197  * Returns: errno
 198  */
 199
 200 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
 201                    struct buffer_head **bhp)
 202 {
 203         struct gfs2_sbd *sdp = gl->gl_sbd;
 204         struct buffer_head *bh;
 205
 206         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
 207                 *bhp = NULL;
 208                 return -EIO;
 209         }
 210
 211         *bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
 212
 213         lock_buffer(bh);
 214         if (buffer_uptodate(bh)) {
 215                 unlock_buffer(bh);
 216                 return 0;
 217         }
 218         bh->b_end_io = end_buffer_read_sync;
 219         get_bh(bh);
 220         submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh);
 221         if (!(flags & DIO_WAIT))
 222                 return 0;
 223
 224         wait_on_buffer(bh);
 225         if (unlikely(!buffer_uptodate(bh))) {
 226                 struct gfs2_trans *tr = current->journal_info;
 227                 if (tr && tr->tr_touched)
 228                         gfs2_io_error_bh(sdp, bh);
 229                 brelse(bh);
 230                 *bhp = NULL;
 231                 return -EIO;
 232         }
 233
 234         return 0;
 235 }
 236
 237 /**
 238  * gfs2_meta_wait - Reread a block from disk
 239  * @sdp: the filesystem
 240  * @bh: The block to wait for
 241  *
 242  * Returns: errno
 243  */
 244
 245 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
 246 {
 247         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 248                 return -EIO;
 249
 250         wait_on_buffer(bh);
 251
 252         if (!buffer_uptodate(bh)) {
 253                 struct gfs2_trans *tr = current->journal_info;
 254                 if (tr && tr->tr_touched)
 255                         gfs2_io_error_bh(sdp, bh);
 256                 return -EIO;
 257         }
 258         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 259                 return -EIO;
 260
 261         return 0;
 262 }
 263
 264 void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
 265 {
 266         struct address_space *mapping = bh->b_page->mapping;
 267         struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
 268         struct gfs2_bufdata *bd = bh->b_private;
 269         int was_pinned = 0;
 270
 271         if (test_clear_buffer_pinned(bh)) {
 272                 trace_gfs2_pin(bd, 0);
 273                 atomic_dec(&sdp->sd_log_pinned);
 274                 list_del_init(&bd->bd_list);
 275                 if (meta)
 276                         tr->tr_num_buf_rm++;
 277                 else
 278                         tr->tr_num_databuf_rm++;
 279                 tr->tr_touched = 1;
 280                 was_pinned = 1;
 281                 brelse(bh);
 282         }
 283         if (bd) {
 284                 spin_lock(&sdp->sd_ail_lock);
 285                 if (bd->bd_tr) {
 286                         gfs2_trans_add_revoke(sdp, bd);
 287                 } else if (was_pinned) {
 288                         bh->b_private = NULL;
 289                         kmem_cache_free(gfs2_bufdata_cachep, bd);
 290                 }
 291                 spin_unlock(&sdp->sd_ail_lock);
 292         }
 293         clear_buffer_dirty(bh);
 294         clear_buffer_uptodate(bh);
 295 }
 296
 297 /**
 298  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 299  * @ip: the inode who owns the buffers
 300  * @bstart: the first buffer in the run
 301  * @blen: the number of buffers in the run
 302  *
 303  */
 304
 305 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
 306 {
 307         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 308         struct buffer_head *bh;
 309
 310         while (blen) {
 311                 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
 312                 if (bh) {
 313                         lock_buffer(bh);
 314                         gfs2_log_lock(sdp);
 315                         gfs2_remove_from_journal(bh, current->journal_info, 1);
 316                         gfs2_log_unlock(sdp);
 317                         unlock_buffer(bh);
 318                         brelse(bh);
 319                 }
 320
 321                 bstart++;
 322                 blen--;
 323         }
 324 }
 325
 326 /**
 327  * gfs2_meta_indirect_buffer - Get a metadata buffer
 328  * @ip: The GFS2 inode
 329  * @height: The level of this buf in the metadata (indir addr) tree (if any)
 330  * @num: The block number (device relative) of the buffer
 331  * @bhp: the buffer is returned here
 332  *
 333  * Returns: errno
 334  */
 335
 336 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
 337                               struct buffer_head **bhp)
 338 {
 339         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 340         struct gfs2_glock *gl = ip->i_gl;
 341         struct buffer_head *bh;
 342         int ret = 0;
 343         u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
 344
 345         ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
 346         if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
 347                 brelse(bh);
 348                 ret = -EIO;
 349         }
 350         *bhp = bh;
 351         return ret;
 352 }
 353
 354 /**
 355  * gfs2_meta_ra - start readahead on an extent of a file
 356  * @gl: the glock the blocks belong to
 357  * @dblock: the starting disk block
 358  * @extlen: the number of blocks in the extent
 359  *
 360  * returns: the first buffer in the extent
 361  */
 362
 363 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
 364 {
 365         struct gfs2_sbd *sdp = gl->gl_sbd;
 366         struct buffer_head *first_bh, *bh;
 367         u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
 368                           sdp->sd_sb.sb_bsize_shift;
 369
 370         BUG_ON(!extlen);
 371
 372         if (max_ra < 1)
 373                 max_ra = 1;
 374         if (extlen > max_ra)
 375                 extlen = max_ra;
 376
 377         first_bh = gfs2_getbuf(gl, dblock, CREATE);
 378
 379         if (buffer_uptodate(first_bh))
 380                 goto out;
 381         if (!buffer_locked(first_bh))
 382                 ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh);
 383
 384         dblock++;
 385         extlen--;
 386
 387         while (extlen) {
 388                 bh = gfs2_getbuf(gl, dblock, CREATE);
 389
 390                 if (!buffer_uptodate(bh) && !buffer_locked(bh))
 391                         ll_rw_block(READA | REQ_META, 1, &bh);
 392                 brelse(bh);
 393                 dblock++;
 394                 extlen--;
 395                 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
 396                         goto out;
 397         }
 398
 399         wait_on_buffer(first_bh);
 400 out:
 401         return first_bh;
 402 }
 403