block: fix bogus gcc warning for uninitialized var usage
[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/kernel.h>
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/quotaops.h>
14
15 #include <asm/byteorder.h>
16
17 #include "quota_tree.h"
18 #include "quotaio_v2.h"
19
20 MODULE_AUTHOR("Jan Kara");
21 MODULE_DESCRIPTION("Quota format v2 support");
22 MODULE_LICENSE("GPL");
23
24 #define __QUOTA_V2_PARANOIA
25
26 static void v2_mem2diskdqb(void *dp, struct dquot *dquot);
27 static void v2_disk2memdqb(struct dquot *dquot, void *dp);
28 static int v2_is_id(void *dp, struct dquot *dquot);
29
30 static struct qtree_fmt_operations v2_qtree_ops = {
31         .mem2disk_dqblk = v2_mem2diskdqb,
32         .disk2mem_dqblk = v2_disk2memdqb,
33         .is_id = v2_is_id,
34 };
35
36 #define QUOTABLOCK_BITS 10
37 #define QUOTABLOCK_SIZE (1 << QUOTABLOCK_BITS)
38
39 static inline qsize_t v2_stoqb(qsize_t space)
40 {
41         return (space + QUOTABLOCK_SIZE - 1) >> QUOTABLOCK_BITS;
42 }
43
44 static inline qsize_t v2_qbtos(qsize_t blocks)
45 {
46         return blocks << QUOTABLOCK_BITS;
47 }
48
49 /* Check whether given file is really vfsv0 quotafile */
50 static int v2_check_quota_file(struct super_block *sb, int type)
51 {
52         struct v2_disk_dqheader dqhead;
53         ssize_t size;
54         static const uint quota_magics[] = V2_INITQMAGICS;
55         static const uint quota_versions[] = V2_INITQVERSIONS;
56  
57         size = sb->s_op->quota_read(sb, type, (char *)&dqhead, sizeof(struct v2_disk_dqheader), 0);
58         if (size != sizeof(struct v2_disk_dqheader)) {
59                 printk("quota_v2: failed read expected=%zd got=%zd\n",
60                         sizeof(struct v2_disk_dqheader), size);
61                 return 0;
62         }
63         if (le32_to_cpu(dqhead.dqh_magic) != quota_magics[type] ||
64             le32_to_cpu(dqhead.dqh_version) != quota_versions[type])
65                 return 0;
66         return 1;
67 }
68
69 /* Read information header from quota file */
70 static int v2_read_file_info(struct super_block *sb, int type)
71 {
72         struct v2_disk_dqinfo dinfo;
73         struct mem_dqinfo *info = sb_dqinfo(sb, type);
74         struct qtree_mem_dqinfo *qinfo;
75         ssize_t size;
76
77         size = sb->s_op->quota_read(sb, type, (char *)&dinfo,
78                sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
79         if (size != sizeof(struct v2_disk_dqinfo)) {
80                 printk(KERN_WARNING "Can't read info structure on device %s.\n",
81                         sb->s_id);
82                 return -1;
83         }
84         info->dqi_priv = kmalloc(sizeof(struct qtree_mem_dqinfo), GFP_NOFS);
85         if (!info->dqi_priv) {
86                 printk(KERN_WARNING
87                        "Not enough memory for quota information structure.\n");
88                 return -1;
89         }
90         qinfo = info->dqi_priv;
91         /* limits are stored as unsigned 32-bit data */
92         info->dqi_maxblimit = 0xffffffff;
93         info->dqi_maxilimit = 0xffffffff;
94         info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
95         info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
96         info->dqi_flags = le32_to_cpu(dinfo.dqi_flags);
97         qinfo->dqi_sb = sb;
98         qinfo->dqi_type = type;
99         qinfo->dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
100         qinfo->dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
101         qinfo->dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
102         qinfo->dqi_blocksize_bits = V2_DQBLKSIZE_BITS;
103         qinfo->dqi_usable_bs = 1 << V2_DQBLKSIZE_BITS;
104         qinfo->dqi_qtree_depth = qtree_depth(qinfo);
105         qinfo->dqi_entry_size = sizeof(struct v2_disk_dqblk);
106         qinfo->dqi_ops = &v2_qtree_ops;
107         return 0;
108 }
109
110 /* Write information header to quota file */
111 static int v2_write_file_info(struct super_block *sb, int type)
112 {
113         struct v2_disk_dqinfo dinfo;
114         struct mem_dqinfo *info = sb_dqinfo(sb, type);
115         struct qtree_mem_dqinfo *qinfo = info->dqi_priv;
116         ssize_t size;
117
118         spin_lock(&dq_data_lock);
119         info->dqi_flags &= ~DQF_INFO_DIRTY;
120         dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
121         dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
122         dinfo.dqi_flags = cpu_to_le32(info->dqi_flags & DQF_MASK);
123         spin_unlock(&dq_data_lock);
124         dinfo.dqi_blocks = cpu_to_le32(qinfo->dqi_blocks);
125         dinfo.dqi_free_blk = cpu_to_le32(qinfo->dqi_free_blk);
126         dinfo.dqi_free_entry = cpu_to_le32(qinfo->dqi_free_entry);
127         size = sb->s_op->quota_write(sb, type, (char *)&dinfo,
128                sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
129         if (size != sizeof(struct v2_disk_dqinfo)) {
130                 printk(KERN_WARNING "Can't write info structure on device %s.\n",
131                         sb->s_id);
132                 return -1;
133         }
134         return 0;
135 }
136
137 static void v2_disk2memdqb(struct dquot *dquot, void *dp)
138 {
139         struct v2_disk_dqblk *d = dp, empty;
140         struct mem_dqblk *m = &dquot->dq_dqb;
141
142         m->dqb_ihardlimit = le32_to_cpu(d->dqb_ihardlimit);
143         m->dqb_isoftlimit = le32_to_cpu(d->dqb_isoftlimit);
144         m->dqb_curinodes = le32_to_cpu(d->dqb_curinodes);
145         m->dqb_itime = le64_to_cpu(d->dqb_itime);
146         m->dqb_bhardlimit = v2_qbtos(le32_to_cpu(d->dqb_bhardlimit));
147         m->dqb_bsoftlimit = v2_qbtos(le32_to_cpu(d->dqb_bsoftlimit));
148         m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
149         m->dqb_btime = le64_to_cpu(d->dqb_btime);
150         /* We need to escape back all-zero structure */
151         memset(&empty, 0, sizeof(struct v2_disk_dqblk));
152         empty.dqb_itime = cpu_to_le64(1);
153         if (!memcmp(&empty, dp, sizeof(struct v2_disk_dqblk)))
154                 m->dqb_itime = 0;
155 }
156
157 static void v2_mem2diskdqb(void *dp, struct dquot *dquot)
158 {
159         struct v2_disk_dqblk *d = dp;
160         struct mem_dqblk *m = &dquot->dq_dqb;
161         struct qtree_mem_dqinfo *info =
162                         sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv;
163
164         d->dqb_ihardlimit = cpu_to_le32(m->dqb_ihardlimit);
165         d->dqb_isoftlimit = cpu_to_le32(m->dqb_isoftlimit);
166         d->dqb_curinodes = cpu_to_le32(m->dqb_curinodes);
167         d->dqb_itime = cpu_to_le64(m->dqb_itime);
168         d->dqb_bhardlimit = cpu_to_le32(v2_stoqb(m->dqb_bhardlimit));
169         d->dqb_bsoftlimit = cpu_to_le32(v2_stoqb(m->dqb_bsoftlimit));
170         d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
171         d->dqb_btime = cpu_to_le64(m->dqb_btime);
172         d->dqb_id = cpu_to_le32(dquot->dq_id);
173         if (qtree_entry_unused(info, dp))
174                 d->dqb_itime = cpu_to_le64(1);
175 }
176
177 static int v2_is_id(void *dp, struct dquot *dquot)
178 {
179         struct v2_disk_dqblk *d = dp;
180         struct qtree_mem_dqinfo *info =
181                         sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv;
182
183         if (qtree_entry_unused(info, dp))
184                 return 0;
185         return le32_to_cpu(d->dqb_id) == dquot->dq_id;
186 }
187
188 static int v2_read_dquot(struct dquot *dquot)
189 {
190         return qtree_read_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv, dquot);
191 }
192
193 static int v2_write_dquot(struct dquot *dquot)
194 {
195         return qtree_write_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv, dquot);
196 }
197
198 static int v2_release_dquot(struct dquot *dquot)
199 {
200         return qtree_release_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv, dquot);
201 }
202
203 static int v2_free_file_info(struct super_block *sb, int type)
204 {
205         kfree(sb_dqinfo(sb, type)->dqi_priv);
206         return 0;
207 }
208
209 static struct quota_format_ops v2_format_ops = {
210         .check_quota_file       = v2_check_quota_file,
211         .read_file_info         = v2_read_file_info,
212         .write_file_info        = v2_write_file_info,
213         .free_file_info         = v2_free_file_info,
214         .read_dqblk             = v2_read_dquot,
215         .commit_dqblk           = v2_write_dquot,
216         .release_dqblk          = v2_release_dquot,
217 };
218
219 static struct quota_format_type v2_quota_format = {
220         .qf_fmt_id      = QFMT_VFS_V0,
221         .qf_ops         = &v2_format_ops,
222         .qf_owner       = THIS_MODULE
223 };
224
225 static int __init init_v2_quota_format(void)
226 {
227         return register_quota_format(&v2_quota_format);
228 }
229
230 static void __exit exit_v2_quota_format(void)
231 {
232         unregister_quota_format(&v2_quota_format);
233 }
234
235 module_init(init_v2_quota_format);
236 module_exit(exit_v2_quota_format);