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 } 233