git.oblomov.eu Git - linux-2.6/blob - fs/ocfs2/buffer_head_io.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * io.c
   5  *
   6  * Buffer cache handling
   7  *
   8  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2 of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public
  21  * License along with this program; if not, write to the
  22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23  * Boston, MA 021110-1307, USA.
  24  */
  25
  26 #include <linux/fs.h>
  27 #include <linux/types.h>
  28 #include <linux/slab.h>
  29 #include <linux/highmem.h>
  30
  31 #include <cluster/masklog.h>
  32
  33 #include "ocfs2.h"
  34
  35 #include "alloc.h"
  36 #include "inode.h"
  37 #include "journal.h"
  38 #include "uptodate.h"
  39
  40 #include "buffer_head_io.h"
  41
  42 int ocfs2_write_block(struct ocfs2_super *osb, struct buffer_head *bh,
  43                       struct inode *inode)
  44 {
  45         int ret = 0;
  46
  47         mlog_entry("(bh->b_blocknr = %llu, inode=%p)\n",
  48                    (unsigned long long)bh->b_blocknr, inode);
  49
  50         BUG_ON(bh->b_blocknr < OCFS2_SUPER_BLOCK_BLKNO);
  51         BUG_ON(buffer_jbd(bh));
  52
  53         /* No need to check for a soft readonly file system here. non
  54          * journalled writes are only ever done on system files which
  55          * can get modified during recovery even if read-only. */
  56         if (ocfs2_is_hard_readonly(osb)) {
  57                 ret = -EROFS;
  58                 goto out;
  59         }
  60
  61         down(&OCFS2_I(inode)->ip_io_sem);
  62
  63         lock_buffer(bh);
  64         set_buffer_uptodate(bh);
  65
  66         /* remove from dirty list before I/O. */
  67         clear_buffer_dirty(bh);
  68
  69         get_bh(bh); /* for end_buffer_write_sync() */
  70         bh->b_end_io = end_buffer_write_sync;
  71         submit_bh(WRITE, bh);
  72
  73         wait_on_buffer(bh);
  74
  75         if (buffer_uptodate(bh)) {
  76                 ocfs2_set_buffer_uptodate(inode, bh);
  77         } else {
  78                 /* We don't need to remove the clustered uptodate
  79                  * information for this bh as it's not marked locally
  80                  * uptodate. */
  81                 ret = -EIO;
  82                 brelse(bh);
  83         }
  84
  85         up(&OCFS2_I(inode)->ip_io_sem);
  86 out:
  87         mlog_exit(ret);
  88         return ret;
  89 }
  90
  91 int ocfs2_read_blocks(struct ocfs2_super *osb, u64 block, int nr,
  92                       struct buffer_head *bhs[], int flags,
  93                       struct inode *inode)
  94 {
  95         int status = 0;
  96         struct super_block *sb;
  97         int i, ignore_cache = 0;
  98         struct buffer_head *bh;
  99
 100         mlog_entry("(block=(%"MLFu64"), nr=(%d), flags=%d, inode=%p)\n",
 101                    block, nr, flags, inode);
 102
 103         if (osb == NULL || osb->sb == NULL || bhs == NULL) {
 104                 status = -EINVAL;
 105                 mlog_errno(status);
 106                 goto bail;
 107         }
 108
 109         if (nr < 0) {
 110                 mlog(ML_ERROR, "asked to read %d blocks!\n", nr);
 111                 status = -EINVAL;
 112                 mlog_errno(status);
 113                 goto bail;
 114         }
 115
 116         if (nr == 0) {
 117                 mlog(ML_BH_IO, "No buffers will be read!\n");
 118                 status = 0;
 119                 goto bail;
 120         }
 121
 122         sb = osb->sb;
 123
 124         if (flags & OCFS2_BH_CACHED && !inode)
 125                 flags &= ~OCFS2_BH_CACHED;
 126
 127         if (inode)
 128                 down(&OCFS2_I(inode)->ip_io_sem);
 129         for (i = 0 ; i < nr ; i++) {
 130                 if (bhs[i] == NULL) {
 131                         bhs[i] = sb_getblk(sb, block++);
 132                         if (bhs[i] == NULL) {
 133                                 if (inode)
 134                                         up(&OCFS2_I(inode)->ip_io_sem);
 135                                 status = -EIO;
 136                                 mlog_errno(status);
 137                                 goto bail;
 138                         }
 139                 }
 140                 bh = bhs[i];
 141                 ignore_cache = 0;
 142
 143                 if (flags & OCFS2_BH_CACHED &&
 144                     !ocfs2_buffer_uptodate(inode, bh)) {
 145                         mlog(ML_UPTODATE,
 146                              "bh (%llu), inode %"MLFu64" not uptodate\n",
 147                              (unsigned long long)bh->b_blocknr,
 148                              OCFS2_I(inode)->ip_blkno);
 149                         ignore_cache = 1;
 150                 }
 151
 152                 /* XXX: Can we ever get this and *not* have the cached
 153                  * flag set? */
 154                 if (buffer_jbd(bh)) {
 155                         if (!(flags & OCFS2_BH_CACHED) || ignore_cache)
 156                                 mlog(ML_BH_IO, "trying to sync read a jbd "
 157                                                "managed bh (blocknr = %llu)\n",
 158                                      (unsigned long long)bh->b_blocknr);
 159                         continue;
 160                 }
 161
 162                 if (!(flags & OCFS2_BH_CACHED) || ignore_cache) {
 163                         if (buffer_dirty(bh)) {
 164                                 /* This should probably be a BUG, or
 165                                  * at least return an error. */
 166                                 mlog(ML_BH_IO, "asking me to sync read a dirty "
 167                                                "buffer! (blocknr = %llu)\n",
 168                                      (unsigned long long)bh->b_blocknr);
 169                                 continue;
 170                         }
 171
 172                         lock_buffer(bh);
 173                         if (buffer_jbd(bh)) {
 174 #ifdef CATCH_BH_JBD_RACES
 175                                 mlog(ML_ERROR, "block %llu had the JBD bit set "
 176                                                "while I was in lock_buffer!",
 177                                      (unsigned long long)bh->b_blocknr);
 178                                 BUG();
 179 #else
 180                                 unlock_buffer(bh);
 181                                 continue;
 182 #endif
 183                         }
 184                         clear_buffer_uptodate(bh);
 185                         get_bh(bh); /* for end_buffer_read_sync() */
 186                         bh->b_end_io = end_buffer_read_sync;
 187                         if (flags & OCFS2_BH_READAHEAD)
 188                                 submit_bh(READA, bh);
 189                         else
 190                                 submit_bh(READ, bh);
 191                         continue;
 192                 }
 193         }
 194
 195         status = 0;
 196
 197         for (i = (nr - 1); i >= 0; i--) {
 198                 bh = bhs[i];
 199
 200                 /* We know this can't have changed as we hold the
 201                  * inode sem. Avoid doing any work on the bh if the
 202                  * journal has it. */
 203                 if (!buffer_jbd(bh))
 204                         wait_on_buffer(bh);
 205
 206                 if (!buffer_uptodate(bh)) {
 207                         /* Status won't be cleared from here on out,
 208                          * so we can safely record this and loop back
 209                          * to cleanup the other buffers. Don't need to
 210                          * remove the clustered uptodate information
 211                          * for this bh as it's not marked locally
 212                          * uptodate. */
 213                         status = -EIO;
 214                         brelse(bh);
 215                         bhs[i] = NULL;
 216                         continue;
 217                 }
 218
 219                 if (inode)
 220                         ocfs2_set_buffer_uptodate(inode, bh);
 221         }
 222         if (inode)
 223                 up(&OCFS2_I(inode)->ip_io_sem);
 224
 225         mlog(ML_BH_IO, "block=(%"MLFu64"), nr=(%d), cached=%s\n", block, nr,
 226              (!(flags & OCFS2_BH_CACHED) || ignore_cache) ? "no" : "yes");
 227
 228 bail:
 229
 230         mlog_exit(status);
 231         return status;
 232 }