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