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_flags = REQ_META | REQ_PRIO |
  41                 (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : 0);
  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(REQ_OP_WRITE, write_flags, 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_name.ln_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_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         put_page(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 static void gfs2_meta_read_endio(struct bio *bio)
 191 {
 192         struct bio_vec *bvec;
 193         int i;
 194
 195         bio_for_each_segment_all(bvec, bio, i) {
 196                 struct page *page = bvec->bv_page;
 197                 struct buffer_head *bh = page_buffers(page);
 198                 unsigned int len = bvec->bv_len;
 199
 200                 while (bh_offset(bh) < bvec->bv_offset)
 201                         bh = bh->b_this_page;
 202                 do {
 203                         struct buffer_head *next = bh->b_this_page;
 204                         len -= bh->b_size;
 205                         bh->b_end_io(bh, !bio->bi_error);
 206                         bh = next;
 207                 } while (bh && len);
 208         }
 209         bio_put(bio);
 210 }
 211
 212 /*
 213  * Submit several consecutive buffer head I/O requests as a single bio I/O
 214  * request.  (See submit_bh_wbc.)
 215  */
 216 static void gfs2_submit_bhs(int op, int op_flags, struct buffer_head *bhs[],
 217                             int num)
 218 {
 219         while (num > 0) {
 220                 struct buffer_head *bh = *bhs;
 221                 struct bio *bio;
 222
 223                 bio = bio_alloc(GFP_NOIO, num);
 224                 bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
 225                 bio->bi_bdev = bh->b_bdev;
 226                 while (num > 0) {
 227                         bh = *bhs;
 228                         if (!bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh))) {
 229                                 BUG_ON(bio->bi_iter.bi_size == 0);
 230                                 break;
 231                         }
 232                         bhs++;
 233                         num--;
 234                 }
 235                 bio->bi_end_io = gfs2_meta_read_endio;
 236                 bio_set_op_attrs(bio, op, op_flags);
 237                 submit_bio(bio);
 238         }
 239 }
 240
 241 /**
 242  * gfs2_meta_read - Read a block from disk
 243  * @gl: The glock covering the block
 244  * @blkno: The block number
 245  * @flags: flags
 246  * @bhp: the place where the buffer is returned (NULL on failure)
 247  *
 248  * Returns: errno
 249  */
 250
 251 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
 252                    int rahead, struct buffer_head **bhp)
 253 {
 254         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 255         struct buffer_head *bh, *bhs[2];
 256         int num = 0;
 257
 258         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
 259                 *bhp = NULL;
 260                 return -EIO;
 261         }
 262
 263         *bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
 264
 265         lock_buffer(bh);
 266         if (buffer_uptodate(bh)) {
 267                 unlock_buffer(bh);
 268                 flags &= ~DIO_WAIT;
 269         } else {
 270                 bh->b_end_io = end_buffer_read_sync;
 271                 get_bh(bh);
 272                 bhs[num++] = bh;
 273         }
 274
 275         if (rahead) {
 276                 bh = gfs2_getbuf(gl, blkno + 1, CREATE);
 277
 278                 lock_buffer(bh);
 279                 if (buffer_uptodate(bh)) {
 280                         unlock_buffer(bh);
 281                         brelse(bh);
 282                 } else {
 283                         bh->b_end_io = end_buffer_read_sync;
 284                         bhs[num++] = bh;
 285                 }
 286         }
 287
 288         gfs2_submit_bhs(REQ_OP_READ, READ_SYNC | REQ_META | REQ_PRIO, bhs, num);
 289         if (!(flags & DIO_WAIT))
 290                 return 0;
 291
 292         bh = *bhp;
 293         wait_on_buffer(bh);
 294         if (unlikely(!buffer_uptodate(bh))) {
 295                 struct gfs2_trans *tr = current->journal_info;
 296                 if (tr && tr->tr_touched)
 297                         gfs2_io_error_bh(sdp, bh);
 298                 brelse(bh);
 299                 *bhp = NULL;
 300                 return -EIO;
 301         }
 302
 303         return 0;
 304 }
 305
 306 /**
 307  * gfs2_meta_wait - Reread a block from disk
 308  * @sdp: the filesystem
 309  * @bh: The block to wait for
 310  *
 311  * Returns: errno
 312  */
 313
 314 int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
 315 {
 316         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 317                 return -EIO;
 318
 319         wait_on_buffer(bh);
 320
 321         if (!buffer_uptodate(bh)) {
 322                 struct gfs2_trans *tr = current->journal_info;
 323                 if (tr && tr->tr_touched)
 324                         gfs2_io_error_bh(sdp, bh);
 325                 return -EIO;
 326         }
 327         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 328                 return -EIO;
 329
 330         return 0;
 331 }
 332
 333 void gfs2_remove_from_journal(struct buffer_head *bh, int meta)
 334 {
 335         struct address_space *mapping = bh->b_page->mapping;
 336         struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
 337         struct gfs2_bufdata *bd = bh->b_private;
 338         struct gfs2_trans *tr = current->journal_info;
 339         int was_pinned = 0;
 340
 341         if (test_clear_buffer_pinned(bh)) {
 342                 trace_gfs2_pin(bd, 0);
 343                 atomic_dec(&sdp->sd_log_pinned);
 344                 list_del_init(&bd->bd_list);
 345                 if (meta == REMOVE_META)
 346                         tr->tr_num_buf_rm++;
 347                 else
 348                         tr->tr_num_databuf_rm++;
 349                 tr->tr_touched = 1;
 350                 was_pinned = 1;
 351                 brelse(bh);
 352         }
 353         if (bd) {
 354                 spin_lock(&sdp->sd_ail_lock);
 355                 if (bd->bd_tr) {
 356                         gfs2_trans_add_revoke(sdp, bd);
 357                 } else if (was_pinned) {
 358                         bh->b_private = NULL;
 359                         kmem_cache_free(gfs2_bufdata_cachep, bd);
 360                 }
 361                 spin_unlock(&sdp->sd_ail_lock);
 362         }
 363         clear_buffer_dirty(bh);
 364         clear_buffer_uptodate(bh);
 365 }
 366
 367 /**
 368  * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 369  * @ip: the inode who owns the buffers
 370  * @bstart: the first buffer in the run
 371  * @blen: the number of buffers in the run
 372  *
 373  */
 374
 375 void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
 376 {
 377         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 378         struct buffer_head *bh;
 379
 380         while (blen) {
 381                 bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
 382                 if (bh) {
 383                         lock_buffer(bh);
 384                         gfs2_log_lock(sdp);
 385                         gfs2_remove_from_journal(bh, REMOVE_META);
 386                         gfs2_log_unlock(sdp);
 387                         unlock_buffer(bh);
 388                         brelse(bh);
 389                 }
 390
 391                 bstart++;
 392                 blen--;
 393         }
 394 }
 395
 396 /**
 397  * gfs2_meta_indirect_buffer - Get a metadata buffer
 398  * @ip: The GFS2 inode
 399  * @height: The level of this buf in the metadata (indir addr) tree (if any)
 400  * @num: The block number (device relative) of the buffer
 401  * @bhp: the buffer is returned here
 402  *
 403  * Returns: errno
 404  */
 405
 406 int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
 407                               struct buffer_head **bhp)
 408 {
 409         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 410         struct gfs2_glock *gl = ip->i_gl;
 411         struct buffer_head *bh;
 412         int ret = 0;
 413         u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
 414         int rahead = 0;
 415
 416         if (num == ip->i_no_addr)
 417                 rahead = ip->i_rahead;
 418
 419         ret = gfs2_meta_read(gl, num, DIO_WAIT, rahead, &bh);
 420         if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
 421                 brelse(bh);
 422                 ret = -EIO;
 423         }
 424         *bhp = bh;
 425         return ret;
 426 }
 427
 428 /**
 429  * gfs2_meta_ra - start readahead on an extent of a file
 430  * @gl: the glock the blocks belong to
 431  * @dblock: the starting disk block
 432  * @extlen: the number of blocks in the extent
 433  *
 434  * returns: the first buffer in the extent
 435  */
 436
 437 struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
 438 {
 439         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 440         struct buffer_head *first_bh, *bh;
 441         u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
 442                           sdp->sd_sb.sb_bsize_shift;
 443
 444         BUG_ON(!extlen);
 445
 446         if (max_ra < 1)
 447                 max_ra = 1;
 448         if (extlen > max_ra)
 449                 extlen = max_ra;
 450
 451         first_bh = gfs2_getbuf(gl, dblock, CREATE);
 452
 453         if (buffer_uptodate(first_bh))
 454                 goto out;
 455         if (!buffer_locked(first_bh))
 456                 ll_rw_block(REQ_OP_READ, READ_SYNC | REQ_META, 1, &first_bh);
 457
 458         dblock++;
 459         extlen--;
 460
 461         while (extlen) {
 462                 bh = gfs2_getbuf(gl, dblock, CREATE);
 463
 464                 if (!buffer_uptodate(bh) && !buffer_locked(bh))
 465                         ll_rw_block(REQ_OP_READ, REQ_RAHEAD | REQ_META, 1, &bh);
 466                 brelse(bh);
 467                 dblock++;
 468                 extlen--;
 469                 if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
 470                         goto out;
 471         }
 472
 473         wait_on_buffer(first_bh);
 474 out:
 475         return first_bh;
 476 }
 477