kernel: Move GPL'd kernel files to sys/gnu to have them all in one place.
[dragonfly.git] / sys / gnu / vfs / ext2fs / ext2_balloc.c
1 /*
2  *  modified for Lites 1.1
3  *
4  *  Aug 1995, Godmar Back (gback@cs.utah.edu)
5  *  University of Utah, Department of Computer Science
6  */
7 /*
8  * Copyright (c) 1982, 1986, 1989, 1993
9  *      The Regents of the University of California.  All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *      This product includes software developed by the University of
22  *      California, Berkeley and its contributors.
23  * 4. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  *
39  *      @(#)ffs_balloc.c        8.4 (Berkeley) 9/23/93
40  * $FreeBSD: src/sys/gnu/ext2fs/ext2_balloc.c,v 1.9.2.1 2000/08/03 00:52:57 peter Exp $
41  */
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/buf.h>
46 #include <sys/lock.h>
47 #include <sys/ucred.h>
48 #include <sys/vnode.h>
49
50 #include "quota.h"
51 #include "inode.h"
52 #include "ext2_fs.h"
53 #include "ext2_fs_sb.h"
54 #include "fs.h"
55 #include "ext2_extern.h"
56
57 /*
58  * Balloc defines the structure of file system storage
59  * by allocating the physical blocks on a device given
60  * the inode and the logical block number in a file.
61  */
62 int
63 ext2_balloc(struct inode *ip, daddr_t bn, int size, struct ucred *cred,
64             struct buf **bpp, int flags)
65 {
66         struct ext2_sb_info *fs;
67         daddr_t nb;
68         struct buf *bp, *nbp;
69         struct vnode *vp = ITOV(ip);
70         struct indir indirs[NIADDR + 2];
71         daddr_t newb, lbn, *bap, pref;
72         int osize, nsize, num, i, error;
73 /*
74 ext2_debug("ext2_balloc called (%d, %d, %d)\n",
75         ip->i_number, (int)bn, (int)size);
76 */
77         *bpp = NULL;
78         if (bn < 0)
79                 return (EFBIG);
80         fs = ip->i_e2fs;
81         lbn = bn;
82
83         /*
84          * check if this is a sequential block allocation.
85          * If so, increment next_alloc fields to allow ext2_blkpref
86          * to make a good guess
87          */
88         if (lbn == ip->i_next_alloc_block + 1) {
89                 ip->i_next_alloc_block++;
90                 ip->i_next_alloc_goal++;
91         }
92
93         /*
94          * The first NDADDR blocks are direct blocks
95          */
96         if (bn < NDADDR) {
97                 nb = ip->i_db[bn];
98                 /* no new block is to be allocated, and no need to expand
99                    the file */
100                 if (nb != 0 && ip->i_size >= (bn + 1) * fs->s_blocksize) {
101                         error = bread(vp, lblktodoff(fs, bn),
102                                       fs->s_blocksize, &bp);
103                         if (error) {
104                                 brelse(bp);
105                                 return (error);
106                         }
107                         *bpp = bp;
108                         return (0);
109                 }
110                 if (nb != 0) {
111                         /*
112                          * Consider need to reallocate a fragment.
113                          */
114                         osize = fragroundup(fs, blkoff(fs, ip->i_size));
115                         nsize = fragroundup(fs, size);
116                         if (nsize <= osize) {
117                                 error = bread(vp, lblktodoff(fs, bn),
118                                               osize, &bp);
119                                 if (error) {
120                                         brelse(bp);
121                                         return (error);
122                                 }
123                         } else {
124                         /* Godmar thinks: this shouldn't happen w/o fragments */
125                                 kprintf("nsize %d(%d) > osize %d(%d) nb %d\n",
126                                         (int)nsize, (int)size, (int)osize,
127                                         (int)ip->i_size, (int)nb);
128                                 panic(
129                                     "ext2_balloc: Something is terribly wrong");
130 /*
131  * please note there haven't been any changes from here on -
132  * FFS seems to work.
133  */
134                         }
135                 } else {
136                         if (ip->i_size < (bn + 1) * fs->s_blocksize)
137                                 nsize = fragroundup(fs, size);
138                         else
139                                 nsize = fs->s_blocksize;
140                         error = ext2_alloc(ip, bn,
141                             ext2_blkpref(ip, bn, (int)bn, &ip->i_db[0], 0),
142                             nsize, cred, &newb);
143                         if (error)
144                                 return (error);
145                         bp = getblk(vp, lblktodoff(fs, bn), nsize, 0, 0);
146                         bp->b_bio2.bio_offset = fsbtodoff(fs, newb);
147                         if (flags & B_CLRBUF)
148                                 vfs_bio_clrbuf(bp);
149                 }
150                 ip->i_db[bn] = dofftofsb(fs, bp->b_bio2.bio_offset);
151                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
152                 *bpp = bp;
153                 return (0);
154         }
155         /*
156          * Determine the number of levels of indirection.
157          */
158         pref = 0;
159         if ((error = ext2_getlbns(vp, bn, indirs, &num)) != 0)
160                 return(error);
161 #if DIAGNOSTIC
162         if (num < 1)
163                 panic ("ext2_balloc: ext2_bmaparray returned indirect block");
164 #endif
165         /*
166          * Fetch the first indirect block allocating if necessary.
167          */
168         --num;
169         nb = ip->i_ib[indirs[0].in_off];
170         if (nb == 0) {
171 #if 0
172                 pref = ext2_blkpref(ip, lbn, 0, NULL, 0);
173 #else
174                 /* see the comment by ext2_blkpref. What we do here is
175                    to pretend that it'd be good for a block holding indirect
176                    pointers to be allocated near its predecessor in terms
177                    of indirection, or the last direct block.
178                    We shamelessly exploit the fact that i_ib immediately
179                    follows i_db.
180                    Godmar thinks it make sense to allocate i_ib[0] immediately
181                    after i_db[11], but it's not utterly clear whether this also
182                    applies to i_ib[1] and i_ib[0]
183                 */
184
185                 pref = ext2_blkpref(ip, lbn, indirs[0].in_off +
186                                              EXT2_NDIR_BLOCKS, &ip->i_db[0], 0);
187 #endif
188                 if ((error = ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize,
189                     cred, &newb)) != 0)
190                         return (error);
191                 nb = newb;
192                 bp = getblk(vp, lblktodoff(fs, indirs[1].in_lbn),
193                             fs->s_blocksize, 0, 0);
194                 bp->b_bio2.bio_offset = fsbtodoff(fs, newb);
195                 vfs_bio_clrbuf(bp);
196                 /*
197                  * Write synchronously so that indirect blocks
198                  * never point at garbage.
199                  */
200                 if ((error = bwrite(bp)) != 0) {
201                         ext2_blkfree(ip, nb, fs->s_blocksize);
202                         return (error);
203                 }
204                 ip->i_ib[indirs[0].in_off] = newb;
205                 ip->i_flag |= IN_CHANGE | IN_UPDATE;
206         }
207         /*
208          * Fetch through the indirect blocks, allocating as necessary.
209          */
210         for (i = 1;;) {
211                 error = bread(vp,
212                               lblktodoff(fs, indirs[i].in_lbn),
213                               (int)fs->s_blocksize, &bp);
214                 if (error) {
215                         brelse(bp);
216                         return (error);
217                 }
218                 bap = (daddr_t *)bp->b_data;
219                 nb = bap[indirs[i].in_off];
220                 if (i == num)
221                         break;
222                 i += 1;
223                 if (nb != 0) {
224                         brelse(bp);
225                         continue;
226                 }
227                 if (pref == 0)
228 #if 1
229                         /* see the comment above and by ext2_blkpref
230                          * I think this implements Linux policy, but
231                          * does it really make sense to allocate to
232                          * block containing pointers together ?
233                          * Also, will it ever succeed ?
234                          */
235                         pref = ext2_blkpref(ip, lbn, indirs[i].in_off, bap,
236                                                 lblkno(fs, bp->b_loffset));
237 #else
238                         pref = ext2_blkpref(ip, lbn, 0, NULL, 0);
239 #endif
240                 if ((error =
241                     ext2_alloc(ip, lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
242                         brelse(bp);
243                         return (error);
244                 }
245                 nb = newb;
246                 nbp = getblk(vp, lblktodoff(fs, indirs[i].in_lbn),
247                              fs->s_blocksize, 0, 0);
248                 nbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
249                 vfs_bio_clrbuf(nbp);
250                 /*
251                  * Write synchronously so that indirect blocks
252                  * never point at garbage.
253                  */
254                 if ((error = bwrite(nbp)) != 0) {
255                         ext2_blkfree(ip, nb, fs->s_blocksize);
256                         brelse(bp);
257                         return (error);
258                 }
259                 bap[indirs[i - 1].in_off] = nb;
260                 /*
261                  * If required, write synchronously, otherwise use
262                  * delayed write.
263                  */
264                 if (flags & B_SYNC) {
265                         bwrite(bp);
266                 } else {
267                         bdwrite(bp);
268                 }
269         }
270         /*
271          * Get the data block, allocating if necessary.
272          */
273         if (nb == 0) {
274                 pref = ext2_blkpref(ip, lbn, indirs[i].in_off, &bap[0],
275                                 lblkno(fs, bp->b_loffset));
276                 if ((error = ext2_alloc(ip,
277                     lbn, pref, (int)fs->s_blocksize, cred, &newb)) != 0) {
278                         brelse(bp);
279                         return (error);
280                 }
281                 nb = newb;
282                 nbp = getblk(vp, lblktodoff(fs, lbn), fs->s_blocksize, 0, 0);
283                 nbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
284                 if (flags & B_CLRBUF)
285                         vfs_bio_clrbuf(nbp);
286                 bap[indirs[i].in_off] = nb;
287                 /*
288                  * If required, write synchronously, otherwise use
289                  * delayed write.
290                  */
291                 if (flags & B_SYNC) {
292                         bwrite(bp);
293                 } else {
294                         bdwrite(bp);
295                 }
296                 *bpp = nbp;
297                 return (0);
298         }
299         brelse(bp);
300         if (flags & B_CLRBUF) {
301                 error = bread(vp, lblktodoff(fs, lbn),
302                               (int)fs->s_blocksize, &nbp);
303                 if (error) {
304                         brelse(nbp);
305                         return (error);
306                 }
307         } else {
308                 nbp = getblk(vp, lblktodoff(fs, lbn), fs->s_blocksize, 0, 0);
309                 nbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
310         }
311         *bpp = nbp;
312         return (0);
313 }