[PATCH] reduce sizeof(struct file)
[linux-2.6] / fs / quota_v2.c
1 /*
2  *      vfsv0 quota IO operations on file
3  */
4
5 #include <linux/errno.h>
6 #include <linux/fs.h>
7 #include <linux/mount.h>
8 #include <linux/dqblk_v2.h>
9 #include <linux/quotaio_v2.h>
10 #include <linux/kernel.h>
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14
15 #include <asm/byteorder.h>
16
17 MODULE_AUTHOR("Jan Kara");
18 MODULE_DESCRIPTION("Quota format v2 support");
19 MODULE_LICENSE("GPL");
20
21 #define __QUOTA_V2_PARANOIA
22
23 typedef char *dqbuf_t;
24
25 #define GETIDINDEX(id, depth) (((id) >> ((V2_DQTREEDEPTH-(depth)-1)*8)) & 0xff)
26 #define GETENTRIES(buf) ((struct v2_disk_dqblk *)(((char *)buf)+sizeof(struct v2_disk_dqdbheader)))
27
28 /* Check whether given file is really vfsv0 quotafile */
29 static int v2_check_quota_file(struct super_block *sb, int type)
30 {
31         struct v2_disk_dqheader dqhead;
32         ssize_t size;
33         static const uint quota_magics[] = V2_INITQMAGICS;
34         static const uint quota_versions[] = V2_INITQVERSIONS;
35  
36         size = sb->s_op->quota_read(sb, type, (char *)&dqhead, sizeof(struct v2_disk_dqheader), 0);
37         if (size != sizeof(struct v2_disk_dqheader)) {
38                 printk("failed read\n");
39                 return 0;
40         }
41         if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type] ||
42             le32_to_cpu(dqhead.dqh_version) != quota_versions[type])
43                 return 0;
44         return 1;
45 }
46
47 /* Read information header from quota file */
48 static int v2_read_file_info(struct super_block *sb, int type)
49 {
50         struct v2_disk_dqinfo dinfo;
51         struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
52         ssize_t size;
53
54         size = sb->s_op->quota_read(sb, type, (char *)&dinfo,
55                sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
56         if (size != sizeof(struct v2_disk_dqinfo)) {
57                 printk(KERN_WARNING "Can't read info structure on device %s.\n",
58                         sb->s_id);
59                 return -1;
60         }
61         info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
62         info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
63         info->dqi_flags = le32_to_cpu(dinfo.dqi_flags);
64         info->u.v2_i.dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
65         info->u.v2_i.dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
66         info->u.v2_i.dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
67         return 0;
68 }
69
70 /* Write information header to quota file */
71 static int v2_write_file_info(struct super_block *sb, int type)
72 {
73         struct v2_disk_dqinfo dinfo;
74         struct mem_dqinfo *info = sb_dqopt(sb)->info+type;
75         ssize_t size;
76
77         spin_lock(&dq_data_lock);
78         info->dqi_flags &= ~DQF_INFO_DIRTY;
79         dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
80         dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
81         dinfo.dqi_flags = cpu_to_le32(info->dqi_flags & DQF_MASK);
82         spin_unlock(&dq_data_lock);
83         dinfo.dqi_blocks = cpu_to_le32(info->u.v2_i.dqi_blocks);
84         dinfo.dqi_free_blk = cpu_to_le32(info->u.v2_i.dqi_free_blk);
85         dinfo.dqi_free_entry = cpu_to_le32(info->u.v2_i.dqi_free_entry);
86         size = sb->s_op->quota_write(sb, type, (char *)&dinfo,
87                sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
88         if (size != sizeof(struct v2_disk_dqinfo)) {
89                 printk(KERN_WARNING "Can't write info structure on device %s.\n",
90                         sb->s_id);
91                 return -1;
92         }
93         return 0;
94 }
95
96 static void disk2memdqb(struct mem_dqblk *m, struct v2_disk_dqblk *d)
97 {
98         m->dqb_ihardlimit = le32_to_cpu(d->dqb_ihardlimit);
99         m->dqb_isoftlimit = le32_to_cpu(d->dqb_isoftlimit);
100         m->dqb_curinodes = le32_to_cpu(d->dqb_curinodes);
101         m->dqb_itime = le64_to_cpu(d->dqb_itime);
102         m->dqb_bhardlimit = le32_to_cpu(d->dqb_bhardlimit);
103         m->dqb_bsoftlimit = le32_to_cpu(d->dqb_bsoftlimit);
104         m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
105         m->dqb_btime = le64_to_cpu(d->dqb_btime);
106 }
107
108 static void mem2diskdqb(struct v2_disk_dqblk *d, struct mem_dqblk *m, qid_t id)
109 {
110         d->dqb_ihardlimit = cpu_to_le32(m->dqb_ihardlimit);
111         d->dqb_isoftlimit = cpu_to_le32(m->dqb_isoftlimit);
112         d->dqb_curinodes = cpu_to_le32(m->dqb_curinodes);
113         d->dqb_itime = cpu_to_le64(m->dqb_itime);
114         d->dqb_bhardlimit = cpu_to_le32(m->dqb_bhardlimit);
115         d->dqb_bsoftlimit = cpu_to_le32(m->dqb_bsoftlimit);
116         d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
117         d->dqb_btime = cpu_to_le64(m->dqb_btime);
118         d->dqb_id = cpu_to_le32(id);
119 }
120
121 static dqbuf_t getdqbuf(void)
122 {
123         dqbuf_t buf = kmalloc(V2_DQBLKSIZE, GFP_NOFS);
124         if (!buf)
125                 printk(KERN_WARNING "VFS: Not enough memory for quota buffers.\n");
126         return buf;
127 }
128
129 static inline void freedqbuf(dqbuf_t buf)
130 {
131         kfree(buf);
132 }
133
134 static inline ssize_t read_blk(struct super_block *sb, int type, uint blk, dqbuf_t buf)
135 {
136         memset(buf, 0, V2_DQBLKSIZE);
137         return sb->s_op->quota_read(sb, type, (char *)buf,
138                V2_DQBLKSIZE, blk << V2_DQBLKSIZE_BITS);
139 }
140
141 static inline ssize_t write_blk(struct super_block *sb, int type, uint blk, dqbuf_t buf)
142 {
143         return sb->s_op->quota_write(sb, type, (char *)buf,
144                V2_DQBLKSIZE, blk << V2_DQBLKSIZE_BITS);
145 }
146
147 /* Remove empty block from list and return it */
148 static int get_free_dqblk(struct super_block *sb, int type)
149 {
150         dqbuf_t buf = getdqbuf();
151         struct mem_dqinfo *info = sb_dqinfo(sb, type);
152         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
153         int ret, blk;
154
155         if (!buf)
156                 return -ENOMEM;
157         if (info->u.v2_i.dqi_free_blk) {
158                 blk = info->u.v2_i.dqi_free_blk;
159                 if ((ret = read_blk(sb, type, blk, buf)) < 0)
160                         goto out_buf;
161                 info->u.v2_i.dqi_free_blk = le32_to_cpu(dh->dqdh_next_free);
162         }
163         else {
164                 memset(buf, 0, V2_DQBLKSIZE);
165                 /* Assure block allocation... */
166                 if ((ret = write_blk(sb, type, info->u.v2_i.dqi_blocks, buf)) < 0)
167                         goto out_buf;
168                 blk = info->u.v2_i.dqi_blocks++;
169         }
170         mark_info_dirty(sb, type);
171         ret = blk;
172 out_buf:
173         freedqbuf(buf);
174         return ret;
175 }
176
177 /* Insert empty block to the list */
178 static int put_free_dqblk(struct super_block *sb, int type, dqbuf_t buf, uint blk)
179 {
180         struct mem_dqinfo *info = sb_dqinfo(sb, type);
181         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
182         int err;
183
184         dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_blk);
185         dh->dqdh_prev_free = cpu_to_le32(0);
186         dh->dqdh_entries = cpu_to_le16(0);
187         info->u.v2_i.dqi_free_blk = blk;
188         mark_info_dirty(sb, type);
189         /* Some strange block. We had better leave it... */
190         if ((err = write_blk(sb, type, blk, buf)) < 0)
191                 return err;
192         return 0;
193 }
194
195 /* Remove given block from the list of blocks with free entries */
196 static int remove_free_dqentry(struct super_block *sb, int type, dqbuf_t buf, uint blk)
197 {
198         dqbuf_t tmpbuf = getdqbuf();
199         struct mem_dqinfo *info = sb_dqinfo(sb, type);
200         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
201         uint nextblk = le32_to_cpu(dh->dqdh_next_free), prevblk = le32_to_cpu(dh->dqdh_prev_free);
202         int err;
203
204         if (!tmpbuf)
205                 return -ENOMEM;
206         if (nextblk) {
207                 if ((err = read_blk(sb, type, nextblk, tmpbuf)) < 0)
208                         goto out_buf;
209                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = dh->dqdh_prev_free;
210                 if ((err = write_blk(sb, type, nextblk, tmpbuf)) < 0)
211                         goto out_buf;
212         }
213         if (prevblk) {
214                 if ((err = read_blk(sb, type, prevblk, tmpbuf)) < 0)
215                         goto out_buf;
216                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_next_free = dh->dqdh_next_free;
217                 if ((err = write_blk(sb, type, prevblk, tmpbuf)) < 0)
218                         goto out_buf;
219         }
220         else {
221                 info->u.v2_i.dqi_free_entry = nextblk;
222                 mark_info_dirty(sb, type);
223         }
224         freedqbuf(tmpbuf);
225         dh->dqdh_next_free = dh->dqdh_prev_free = cpu_to_le32(0);
226         /* No matter whether write succeeds block is out of list */
227         if (write_blk(sb, type, blk, buf) < 0)
228                 printk(KERN_ERR "VFS: Can't write block (%u) with free entries.\n", blk);
229         return 0;
230 out_buf:
231         freedqbuf(tmpbuf);
232         return err;
233 }
234
235 /* Insert given block to the beginning of list with free entries */
236 static int insert_free_dqentry(struct super_block *sb, int type, dqbuf_t buf, uint blk)
237 {
238         dqbuf_t tmpbuf = getdqbuf();
239         struct mem_dqinfo *info = sb_dqinfo(sb, type);
240         struct v2_disk_dqdbheader *dh = (struct v2_disk_dqdbheader *)buf;
241         int err;
242
243         if (!tmpbuf)
244                 return -ENOMEM;
245         dh->dqdh_next_free = cpu_to_le32(info->u.v2_i.dqi_free_entry);
246         dh->dqdh_prev_free = cpu_to_le32(0);
247         if ((err = write_blk(sb, type, blk, buf)) < 0)
248                 goto out_buf;
249         if (info->u.v2_i.dqi_free_entry) {
250                 if ((err = read_blk(sb, type, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
251                         goto out_buf;
252                 ((struct v2_disk_dqdbheader *)tmpbuf)->dqdh_prev_free = cpu_to_le32(blk);
253                 if ((err = write_blk(sb, type, info->u.v2_i.dqi_free_entry, tmpbuf)) < 0)
254                         goto out_buf;
255         }
256         freedqbuf(tmpbuf);
257         info->u.v2_i.dqi_free_entry = blk;
258         mark_info_dirty(sb, type);
259         return 0;
260 out_buf:
261         freedqbuf(tmpbuf);
262         return err;
263 }
264
265 /* Find space for dquot */
266 static uint find_free_dqentry(struct dquot *dquot, int *err)
267 {
268         struct super_block *sb = dquot->dq_sb;
269         struct mem_dqinfo *info = sb_dqopt(sb)->info+dquot->dq_type;
270         uint blk, i;
271         struct v2_disk_dqdbheader *dh;
272         struct v2_disk_dqblk *ddquot;
273         struct v2_disk_dqblk fakedquot;
274         dqbuf_t buf;
275
276         *err = 0;
277         if (!(buf = getdqbuf())) {
278                 *err = -ENOMEM;
279                 return 0;
280         }
281         dh = (struct v2_disk_dqdbheader *)buf;
282         ddquot = GETENTRIES(buf);
283         if (info->u.v2_i.dqi_free_entry) {
284                 blk = info->u.v2_i.dqi_free_entry;
285                 if ((*err = read_blk(sb, dquot->dq_type, blk, buf)) < 0)
286                         goto out_buf;
287         }
288         else {
289                 blk = get_free_dqblk(sb, dquot->dq_type);
290                 if ((int)blk < 0) {
291                         *err = blk;
292                         freedqbuf(buf);
293                         return 0;
294                 }
295                 memset(buf, 0, V2_DQBLKSIZE);
296                 /* This is enough as block is already zeroed and entry list is empty... */
297                 info->u.v2_i.dqi_free_entry = blk;
298                 mark_info_dirty(sb, dquot->dq_type);
299         }
300         if (le16_to_cpu(dh->dqdh_entries)+1 >= V2_DQSTRINBLK)   /* Block will be full? */
301                 if ((*err = remove_free_dqentry(sb, dquot->dq_type, buf, blk)) < 0) {
302                         printk(KERN_ERR "VFS: find_free_dqentry(): Can't remove block (%u) from entry free list.\n", blk);
303                         goto out_buf;
304                 }
305         dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)+1);
306         memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
307         /* Find free structure in block */
308         for (i = 0; i < V2_DQSTRINBLK && memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)); i++);
309 #ifdef __QUOTA_V2_PARANOIA
310         if (i == V2_DQSTRINBLK) {
311                 printk(KERN_ERR "VFS: find_free_dqentry(): Data block full but it shouldn't.\n");
312                 *err = -EIO;
313                 goto out_buf;
314         }
315 #endif
316         if ((*err = write_blk(sb, dquot->dq_type, blk, buf)) < 0) {
317                 printk(KERN_ERR "VFS: find_free_dqentry(): Can't write quota data block %u.\n", blk);
318                 goto out_buf;
319         }
320         dquot->dq_off = (blk<<V2_DQBLKSIZE_BITS)+sizeof(struct v2_disk_dqdbheader)+i*sizeof(struct v2_disk_dqblk);
321         freedqbuf(buf);
322         return blk;
323 out_buf:
324         freedqbuf(buf);
325         return 0;
326 }
327
328 /* Insert reference to structure into the trie */
329 static int do_insert_tree(struct dquot *dquot, uint *treeblk, int depth)
330 {
331         struct super_block *sb = dquot->dq_sb;
332         dqbuf_t buf;
333         int ret = 0, newson = 0, newact = 0;
334         __le32 *ref;
335         uint newblk;
336
337         if (!(buf = getdqbuf()))
338                 return -ENOMEM;
339         if (!*treeblk) {
340                 ret = get_free_dqblk(sb, dquot->dq_type);
341                 if (ret < 0)
342                         goto out_buf;
343                 *treeblk = ret;
344                 memset(buf, 0, V2_DQBLKSIZE);
345                 newact = 1;
346         }
347         else {
348                 if ((ret = read_blk(sb, dquot->dq_type, *treeblk, buf)) < 0) {
349                         printk(KERN_ERR "VFS: Can't read tree quota block %u.\n", *treeblk);
350                         goto out_buf;
351                 }
352         }
353         ref = (__le32 *)buf;
354         newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
355         if (!newblk)
356                 newson = 1;
357         if (depth == V2_DQTREEDEPTH-1) {
358 #ifdef __QUOTA_V2_PARANOIA
359                 if (newblk) {
360                         printk(KERN_ERR "VFS: Inserting already present quota entry (block %u).\n", le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]));
361                         ret = -EIO;
362                         goto out_buf;
363                 }
364 #endif
365                 newblk = find_free_dqentry(dquot, &ret);
366         }
367         else
368                 ret = do_insert_tree(dquot, &newblk, depth+1);
369         if (newson && ret >= 0) {
370                 ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(newblk);
371                 ret = write_blk(sb, dquot->dq_type, *treeblk, buf);
372         }
373         else if (newact && ret < 0)
374                 put_free_dqblk(sb, dquot->dq_type, buf, *treeblk);
375 out_buf:
376         freedqbuf(buf);
377         return ret;
378 }
379
380 /* Wrapper for inserting quota structure into tree */
381 static inline int dq_insert_tree(struct dquot *dquot)
382 {
383         int tmp = V2_DQTREEOFF;
384         return do_insert_tree(dquot, &tmp, 0);
385 }
386
387 /*
388  *      We don't have to be afraid of deadlocks as we never have quotas on quota files...
389  */
390 static int v2_write_dquot(struct dquot *dquot)
391 {
392         int type = dquot->dq_type;
393         ssize_t ret;
394         struct v2_disk_dqblk ddquot, empty;
395
396         /* dq_off is guarded by dqio_sem */
397         if (!dquot->dq_off)
398                 if ((ret = dq_insert_tree(dquot)) < 0) {
399                         printk(KERN_ERR "VFS: Error %zd occurred while creating quota.\n", ret);
400                         return ret;
401                 }
402         spin_lock(&dq_data_lock);
403         mem2diskdqb(&ddquot, &dquot->dq_dqb, dquot->dq_id);
404         /* Argh... We may need to write structure full of zeroes but that would be
405          * treated as an empty place by the rest of the code. Format change would
406          * be definitely cleaner but the problems probably are not worth it */
407         memset(&empty, 0, sizeof(struct v2_disk_dqblk));
408         if (!memcmp(&empty, &ddquot, sizeof(struct v2_disk_dqblk)))
409                 ddquot.dqb_itime = cpu_to_le64(1);
410         spin_unlock(&dq_data_lock);
411         ret = dquot->dq_sb->s_op->quota_write(dquot->dq_sb, type,
412               (char *)&ddquot, sizeof(struct v2_disk_dqblk), dquot->dq_off);
413         if (ret != sizeof(struct v2_disk_dqblk)) {
414                 printk(KERN_WARNING "VFS: dquota write failed on dev %s\n", dquot->dq_sb->s_id);
415                 if (ret >= 0)
416                         ret = -ENOSPC;
417         }
418         else
419                 ret = 0;
420         dqstats.writes++;
421
422         return ret;
423 }
424
425 /* Free dquot entry in data block */
426 static int free_dqentry(struct dquot *dquot, uint blk)
427 {
428         struct super_block *sb = dquot->dq_sb;
429         int type = dquot->dq_type;
430         struct v2_disk_dqdbheader *dh;
431         dqbuf_t buf = getdqbuf();
432         int ret = 0;
433
434         if (!buf)
435                 return -ENOMEM;
436         if (dquot->dq_off >> V2_DQBLKSIZE_BITS != blk) {
437                 printk(KERN_ERR "VFS: Quota structure has offset to other "
438                   "block (%u) than it should (%u).\n", blk,
439                   (uint)(dquot->dq_off >> V2_DQBLKSIZE_BITS));
440                 goto out_buf;
441         }
442         if ((ret = read_blk(sb, type, blk, buf)) < 0) {
443                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", blk);
444                 goto out_buf;
445         }
446         dh = (struct v2_disk_dqdbheader *)buf;
447         dh->dqdh_entries = cpu_to_le16(le16_to_cpu(dh->dqdh_entries)-1);
448         if (!le16_to_cpu(dh->dqdh_entries)) {   /* Block got free? */
449                 if ((ret = remove_free_dqentry(sb, type, buf, blk)) < 0 ||
450                     (ret = put_free_dqblk(sb, type, buf, blk)) < 0) {
451                         printk(KERN_ERR "VFS: Can't move quota data block (%u) "
452                           "to free list.\n", blk);
453                         goto out_buf;
454                 }
455         }
456         else {
457                 memset(buf+(dquot->dq_off & ((1 << V2_DQBLKSIZE_BITS)-1)), 0,
458                   sizeof(struct v2_disk_dqblk));
459                 if (le16_to_cpu(dh->dqdh_entries) == V2_DQSTRINBLK-1) {
460                         /* Insert will write block itself */
461                         if ((ret = insert_free_dqentry(sb, type, buf, blk)) < 0) {
462                                 printk(KERN_ERR "VFS: Can't insert quota data block (%u) to free entry list.\n", blk);
463                                 goto out_buf;
464                         }
465                 }
466                 else
467                         if ((ret = write_blk(sb, type, blk, buf)) < 0) {
468                                 printk(KERN_ERR "VFS: Can't write quota data "
469                                   "block %u\n", blk);
470                                 goto out_buf;
471                         }
472         }
473         dquot->dq_off = 0;      /* Quota is now unattached */
474 out_buf:
475         freedqbuf(buf);
476         return ret;
477 }
478
479 /* Remove reference to dquot from tree */
480 static int remove_tree(struct dquot *dquot, uint *blk, int depth)
481 {
482         struct super_block *sb = dquot->dq_sb;
483         int type = dquot->dq_type;
484         dqbuf_t buf = getdqbuf();
485         int ret = 0;
486         uint newblk;
487         __le32 *ref = (__le32 *)buf;
488         
489         if (!buf)
490                 return -ENOMEM;
491         if ((ret = read_blk(sb, type, *blk, buf)) < 0) {
492                 printk(KERN_ERR "VFS: Can't read quota data block %u\n", *blk);
493                 goto out_buf;
494         }
495         newblk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
496         if (depth == V2_DQTREEDEPTH-1) {
497                 ret = free_dqentry(dquot, newblk);
498                 newblk = 0;
499         }
500         else
501                 ret = remove_tree(dquot, &newblk, depth+1);
502         if (ret >= 0 && !newblk) {
503                 int i;
504                 ref[GETIDINDEX(dquot->dq_id, depth)] = cpu_to_le32(0);
505                 for (i = 0; i < V2_DQBLKSIZE && !buf[i]; i++);  /* Block got empty? */
506                 /* Don't put the root block into the free block list */
507                 if (i == V2_DQBLKSIZE && *blk != V2_DQTREEOFF) {
508                         put_free_dqblk(sb, type, buf, *blk);
509                         *blk = 0;
510                 }
511                 else
512                         if ((ret = write_blk(sb, type, *blk, buf)) < 0)
513                                 printk(KERN_ERR "VFS: Can't write quota tree "
514                                   "block %u.\n", *blk);
515         }
516 out_buf:
517         freedqbuf(buf);
518         return ret;     
519 }
520
521 /* Delete dquot from tree */
522 static int v2_delete_dquot(struct dquot *dquot)
523 {
524         uint tmp = V2_DQTREEOFF;
525
526         if (!dquot->dq_off)     /* Even not allocated? */
527                 return 0;
528         return remove_tree(dquot, &tmp, 0);
529 }
530
531 /* Find entry in block */
532 static loff_t find_block_dqentry(struct dquot *dquot, uint blk)
533 {
534         dqbuf_t buf = getdqbuf();
535         loff_t ret = 0;
536         int i;
537         struct v2_disk_dqblk *ddquot = GETENTRIES(buf);
538
539         if (!buf)
540                 return -ENOMEM;
541         if ((ret = read_blk(dquot->dq_sb, dquot->dq_type, blk, buf)) < 0) {
542                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
543                 goto out_buf;
544         }
545         if (dquot->dq_id)
546                 for (i = 0; i < V2_DQSTRINBLK &&
547                      le32_to_cpu(ddquot[i].dqb_id) != dquot->dq_id; i++);
548         else {  /* ID 0 as a bit more complicated searching... */
549                 struct v2_disk_dqblk fakedquot;
550
551                 memset(&fakedquot, 0, sizeof(struct v2_disk_dqblk));
552                 for (i = 0; i < V2_DQSTRINBLK; i++)
553                         if (!le32_to_cpu(ddquot[i].dqb_id) &&
554                             memcmp(&fakedquot, ddquot+i, sizeof(struct v2_disk_dqblk)))
555                                 break;
556         }
557         if (i == V2_DQSTRINBLK) {
558                 printk(KERN_ERR "VFS: Quota for id %u referenced "
559                   "but not present.\n", dquot->dq_id);
560                 ret = -EIO;
561                 goto out_buf;
562         }
563         else
564                 ret = (blk << V2_DQBLKSIZE_BITS) + sizeof(struct
565                   v2_disk_dqdbheader) + i * sizeof(struct v2_disk_dqblk);
566 out_buf:
567         freedqbuf(buf);
568         return ret;
569 }
570
571 /* Find entry for given id in the tree */
572 static loff_t find_tree_dqentry(struct dquot *dquot, uint blk, int depth)
573 {
574         dqbuf_t buf = getdqbuf();
575         loff_t ret = 0;
576         __le32 *ref = (__le32 *)buf;
577
578         if (!buf)
579                 return -ENOMEM;
580         if ((ret = read_blk(dquot->dq_sb, dquot->dq_type, blk, buf)) < 0) {
581                 printk(KERN_ERR "VFS: Can't read quota tree block %u.\n", blk);
582                 goto out_buf;
583         }
584         ret = 0;
585         blk = le32_to_cpu(ref[GETIDINDEX(dquot->dq_id, depth)]);
586         if (!blk)       /* No reference? */
587                 goto out_buf;
588         if (depth < V2_DQTREEDEPTH-1)
589                 ret = find_tree_dqentry(dquot, blk, depth+1);
590         else
591                 ret = find_block_dqentry(dquot, blk);
592 out_buf:
593         freedqbuf(buf);
594         return ret;
595 }
596
597 /* Find entry for given id in the tree - wrapper function */
598 static inline loff_t find_dqentry(struct dquot *dquot)
599 {
600         return find_tree_dqentry(dquot, V2_DQTREEOFF, 0);
601 }
602
603 static int v2_read_dquot(struct dquot *dquot)
604 {
605         int type = dquot->dq_type;
606         loff_t offset;
607         struct v2_disk_dqblk ddquot, empty;
608         int ret = 0;
609
610 #ifdef __QUOTA_V2_PARANOIA
611         /* Invalidated quota? */
612         if (!dquot->dq_sb || !sb_dqopt(dquot->dq_sb)->files[type]) {
613                 printk(KERN_ERR "VFS: Quota invalidated while reading!\n");
614                 return -EIO;
615         }
616 #endif
617         offset = find_dqentry(dquot);
618         if (offset <= 0) {      /* Entry not present? */
619                 if (offset < 0)
620                         printk(KERN_ERR "VFS: Can't read quota "
621                           "structure for id %u.\n", dquot->dq_id);
622                 dquot->dq_off = 0;
623                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
624                 memset(&dquot->dq_dqb, 0, sizeof(struct mem_dqblk));
625                 ret = offset;
626         }
627         else {
628                 dquot->dq_off = offset;
629                 if ((ret = dquot->dq_sb->s_op->quota_read(dquot->dq_sb, type,
630                     (char *)&ddquot, sizeof(struct v2_disk_dqblk), offset))
631                     != sizeof(struct v2_disk_dqblk)) {
632                         if (ret >= 0)
633                                 ret = -EIO;
634                         printk(KERN_ERR "VFS: Error while reading quota "
635                           "structure for id %u.\n", dquot->dq_id);
636                         memset(&ddquot, 0, sizeof(struct v2_disk_dqblk));
637                 }
638                 else {
639                         ret = 0;
640                         /* We need to escape back all-zero structure */
641                         memset(&empty, 0, sizeof(struct v2_disk_dqblk));
642                         empty.dqb_itime = cpu_to_le64(1);
643                         if (!memcmp(&empty, &ddquot, sizeof(struct v2_disk_dqblk)))
644                                 ddquot.dqb_itime = 0;
645                 }
646                 disk2memdqb(&dquot->dq_dqb, &ddquot);
647                 if (!dquot->dq_dqb.dqb_bhardlimit &&
648                         !dquot->dq_dqb.dqb_bsoftlimit &&
649                         !dquot->dq_dqb.dqb_ihardlimit &&
650                         !dquot->dq_dqb.dqb_isoftlimit)
651                         set_bit(DQ_FAKE_B, &dquot->dq_flags);
652         }
653         dqstats.reads++;
654
655         return ret;
656 }
657
658 /* Check whether dquot should not be deleted. We know we are
659  * the only one operating on dquot (thanks to dq_lock) */
660 static int v2_release_dquot(struct dquot *dquot)
661 {
662         if (test_bit(DQ_FAKE_B, &dquot->dq_flags) && !(dquot->dq_dqb.dqb_curinodes | dquot->dq_dqb.dqb_curspace))
663                 return v2_delete_dquot(dquot);
664         return 0;
665 }
666
667 static struct quota_format_ops v2_format_ops = {
668         .check_quota_file       = v2_check_quota_file,
669         .read_file_info         = v2_read_file_info,
670         .write_file_info        = v2_write_file_info,
671         .free_file_info         = NULL,
672         .read_dqblk             = v2_read_dquot,
673         .commit_dqblk           = v2_write_dquot,
674         .release_dqblk          = v2_release_dquot,
675 };
676
677 static struct quota_format_type v2_quota_format = {
678         .qf_fmt_id      = QFMT_VFS_V0,
679         .qf_ops         = &v2_format_ops,
680         .qf_owner       = THIS_MODULE
681 };
682
683 static int __init init_v2_quota_format(void)
684 {
685         return register_quota_format(&v2_quota_format);
686 }
687
688 static void __exit exit_v2_quota_format(void)
689 {
690         unregister_quota_format(&v2_quota_format);
691 }
692
693 module_init(init_v2_quota_format);
694 module_exit(exit_v2_quota_format);