blob: c9037414f4f65fad9f0b812b9ba75f7c9823cc6d [file] [log] [blame]
Mark Fashehccd979b2005-12-15 14:31:24 -08001/* -*- 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
42int 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
Mark Fasheh251b6ec2006-01-10 15:41:43 -080061 mutex_lock(&OCFS2_I(inode)->ip_io_mutex);
Mark Fashehccd979b2005-12-15 14:31:24 -080062
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
Mark Fasheh251b6ec2006-01-10 15:41:43 -080085 mutex_unlock(&OCFS2_I(inode)->ip_io_mutex);
Mark Fashehccd979b2005-12-15 14:31:24 -080086out:
87 mlog_exit(ret);
88 return ret;
89}
90
91int 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
Mark Fashehb06970532006-03-03 10:24:33 -0800100 mlog_entry("(block=(%llu), nr=(%d), flags=%d, inode=%p)\n",
101 (unsigned long long)block, nr, flags, inode);
Mark Fashehccd979b2005-12-15 14:31:24 -0800102
Mark Fashehaa958872006-04-21 13:49:02 -0700103 BUG_ON((flags & OCFS2_BH_READAHEAD) &&
104 (!inode || !(flags & OCFS2_BH_CACHED)));
105
Mark Fashehccd979b2005-12-15 14:31:24 -0800106 if (osb == NULL || osb->sb == NULL || bhs == NULL) {
107 status = -EINVAL;
108 mlog_errno(status);
109 goto bail;
110 }
111
112 if (nr < 0) {
113 mlog(ML_ERROR, "asked to read %d blocks!\n", nr);
114 status = -EINVAL;
115 mlog_errno(status);
116 goto bail;
117 }
118
119 if (nr == 0) {
120 mlog(ML_BH_IO, "No buffers will be read!\n");
121 status = 0;
122 goto bail;
123 }
124
125 sb = osb->sb;
126
127 if (flags & OCFS2_BH_CACHED && !inode)
128 flags &= ~OCFS2_BH_CACHED;
129
130 if (inode)
Mark Fasheh251b6ec2006-01-10 15:41:43 -0800131 mutex_lock(&OCFS2_I(inode)->ip_io_mutex);
Mark Fashehccd979b2005-12-15 14:31:24 -0800132 for (i = 0 ; i < nr ; i++) {
133 if (bhs[i] == NULL) {
134 bhs[i] = sb_getblk(sb, block++);
135 if (bhs[i] == NULL) {
136 if (inode)
Mark Fasheh251b6ec2006-01-10 15:41:43 -0800137 mutex_unlock(&OCFS2_I(inode)->ip_io_mutex);
Mark Fashehccd979b2005-12-15 14:31:24 -0800138 status = -EIO;
139 mlog_errno(status);
140 goto bail;
141 }
142 }
143 bh = bhs[i];
144 ignore_cache = 0;
145
Mark Fashehaa958872006-04-21 13:49:02 -0700146 /* There are three read-ahead cases here which we need to
147 * be concerned with. All three assume a buffer has
148 * previously been submitted with OCFS2_BH_READAHEAD
149 * and it hasn't yet completed I/O.
150 *
151 * 1) The current request is sync to disk. This rarely
152 * happens these days, and never when performance
153 * matters - the code can just wait on the buffer
154 * lock and re-submit.
155 *
156 * 2) The current request is cached, but not
157 * readahead. ocfs2_buffer_uptodate() will return
158 * false anyway, so we'll wind up waiting on the
159 * buffer lock to do I/O. We re-check the request
160 * with after getting the lock to avoid a re-submit.
161 *
162 * 3) The current request is readahead (and so must
163 * also be a caching one). We short circuit if the
164 * buffer is locked (under I/O) and if it's in the
165 * uptodate cache. The re-check from #2 catches the
166 * case that the previous read-ahead completes just
167 * before our is-it-in-flight check.
168 */
169
Mark Fashehccd979b2005-12-15 14:31:24 -0800170 if (flags & OCFS2_BH_CACHED &&
171 !ocfs2_buffer_uptodate(inode, bh)) {
172 mlog(ML_UPTODATE,
Mark Fashehb06970532006-03-03 10:24:33 -0800173 "bh (%llu), inode %llu not uptodate\n",
Mark Fashehccd979b2005-12-15 14:31:24 -0800174 (unsigned long long)bh->b_blocknr,
Mark Fashehb06970532006-03-03 10:24:33 -0800175 (unsigned long long)OCFS2_I(inode)->ip_blkno);
Mark Fashehccd979b2005-12-15 14:31:24 -0800176 ignore_cache = 1;
177 }
178
179 /* XXX: Can we ever get this and *not* have the cached
180 * flag set? */
181 if (buffer_jbd(bh)) {
182 if (!(flags & OCFS2_BH_CACHED) || ignore_cache)
183 mlog(ML_BH_IO, "trying to sync read a jbd "
184 "managed bh (blocknr = %llu)\n",
185 (unsigned long long)bh->b_blocknr);
186 continue;
187 }
188
189 if (!(flags & OCFS2_BH_CACHED) || ignore_cache) {
190 if (buffer_dirty(bh)) {
191 /* This should probably be a BUG, or
192 * at least return an error. */
193 mlog(ML_BH_IO, "asking me to sync read a dirty "
194 "buffer! (blocknr = %llu)\n",
195 (unsigned long long)bh->b_blocknr);
196 continue;
197 }
198
Mark Fashehaa958872006-04-21 13:49:02 -0700199 /* A read-ahead request was made - if the
200 * buffer is already under read-ahead from a
201 * previously submitted request than we are
202 * done here. */
203 if ((flags & OCFS2_BH_READAHEAD)
204 && ocfs2_buffer_read_ahead(inode, bh))
205 continue;
206
Mark Fashehccd979b2005-12-15 14:31:24 -0800207 lock_buffer(bh);
208 if (buffer_jbd(bh)) {
209#ifdef CATCH_BH_JBD_RACES
210 mlog(ML_ERROR, "block %llu had the JBD bit set "
211 "while I was in lock_buffer!",
212 (unsigned long long)bh->b_blocknr);
213 BUG();
214#else
215 unlock_buffer(bh);
216 continue;
217#endif
218 }
Mark Fashehaa958872006-04-21 13:49:02 -0700219
220 /* Re-check ocfs2_buffer_uptodate() as a
221 * previously read-ahead buffer may have
222 * completed I/O while we were waiting for the
223 * buffer lock. */
224 if ((flags & OCFS2_BH_CACHED)
225 && !(flags & OCFS2_BH_READAHEAD)
226 && ocfs2_buffer_uptodate(inode, bh)) {
227 unlock_buffer(bh);
228 continue;
229 }
230
Mark Fashehccd979b2005-12-15 14:31:24 -0800231 clear_buffer_uptodate(bh);
232 get_bh(bh); /* for end_buffer_read_sync() */
233 bh->b_end_io = end_buffer_read_sync;
Mark Fashehaa958872006-04-21 13:49:02 -0700234 submit_bh(READ, bh);
Mark Fashehccd979b2005-12-15 14:31:24 -0800235 continue;
236 }
237 }
238
239 status = 0;
240
241 for (i = (nr - 1); i >= 0; i--) {
242 bh = bhs[i];
243
Mark Fashehaa958872006-04-21 13:49:02 -0700244 if (!(flags & OCFS2_BH_READAHEAD)) {
245 /* We know this can't have changed as we hold the
246 * inode sem. Avoid doing any work on the bh if the
247 * journal has it. */
248 if (!buffer_jbd(bh))
249 wait_on_buffer(bh);
Mark Fashehccd979b2005-12-15 14:31:24 -0800250
Mark Fashehaa958872006-04-21 13:49:02 -0700251 if (!buffer_uptodate(bh)) {
252 /* Status won't be cleared from here on out,
253 * so we can safely record this and loop back
254 * to cleanup the other buffers. Don't need to
255 * remove the clustered uptodate information
256 * for this bh as it's not marked locally
257 * uptodate. */
258 status = -EIO;
259 brelse(bh);
260 bhs[i] = NULL;
261 continue;
262 }
Mark Fashehccd979b2005-12-15 14:31:24 -0800263 }
264
Mark Fashehaa958872006-04-21 13:49:02 -0700265 /* Always set the buffer in the cache, even if it was
266 * a forced read, or read-ahead which hasn't yet
267 * completed. */
Mark Fashehccd979b2005-12-15 14:31:24 -0800268 if (inode)
269 ocfs2_set_buffer_uptodate(inode, bh);
270 }
271 if (inode)
Mark Fasheh251b6ec2006-01-10 15:41:43 -0800272 mutex_unlock(&OCFS2_I(inode)->ip_io_mutex);
Mark Fashehccd979b2005-12-15 14:31:24 -0800273
Mark Fashehaa958872006-04-21 13:49:02 -0700274 mlog(ML_BH_IO, "block=(%llu), nr=(%d), cached=%s, flags=0x%x\n",
Mark Fashehb06970532006-03-03 10:24:33 -0800275 (unsigned long long)block, nr,
Mark Fashehaa958872006-04-21 13:49:02 -0700276 (!(flags & OCFS2_BH_CACHED) || ignore_cache) ? "no" : "yes", flags);
Mark Fashehccd979b2005-12-15 14:31:24 -0800277
278bail:
279
280 mlog_exit(status);
281 return status;
282}