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TOMOYO Linux Cross Reference
Linux/fs/efs/super.c

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  1 /*
  2  * super.c
  3  *
  4  * Copyright (c) 1999 Al Smith
  5  *
  6  * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
  7  */
  8 
  9 #include <linux/init.h>
 10 #include <linux/module.h>
 11 #include <linux/exportfs.h>
 12 #include <linux/slab.h>
 13 #include <linux/buffer_head.h>
 14 #include <linux/vfs.h>
 15 
 16 #include "efs.h"
 17 #include <linux/efs_vh.h>
 18 #include <linux/efs_fs_sb.h>
 19 
 20 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
 21 static int efs_fill_super(struct super_block *s, void *d, int silent);
 22 
 23 static struct dentry *efs_mount(struct file_system_type *fs_type,
 24         int flags, const char *dev_name, void *data)
 25 {
 26         return mount_bdev(fs_type, flags, dev_name, data, efs_fill_super);
 27 }
 28 
 29 static void efs_kill_sb(struct super_block *s)
 30 {
 31         struct efs_sb_info *sbi = SUPER_INFO(s);
 32         kill_block_super(s);
 33         kfree(sbi);
 34 }
 35 
 36 static struct file_system_type efs_fs_type = {
 37         .owner          = THIS_MODULE,
 38         .name           = "efs",
 39         .mount          = efs_mount,
 40         .kill_sb        = efs_kill_sb,
 41         .fs_flags       = FS_REQUIRES_DEV,
 42 };
 43 MODULE_ALIAS_FS("efs");
 44 
 45 static struct pt_types sgi_pt_types[] = {
 46         {0x00,          "SGI vh"},
 47         {0x01,          "SGI trkrepl"},
 48         {0x02,          "SGI secrepl"},
 49         {0x03,          "SGI raw"},
 50         {0x04,          "SGI bsd"},
 51         {SGI_SYSV,      "SGI sysv"},
 52         {0x06,          "SGI vol"},
 53         {SGI_EFS,       "SGI efs"},
 54         {0x08,          "SGI lv"},
 55         {0x09,          "SGI rlv"},
 56         {0x0A,          "SGI xfs"},
 57         {0x0B,          "SGI xfslog"},
 58         {0x0C,          "SGI xlv"},
 59         {0x82,          "Linux swap"},
 60         {0x83,          "Linux native"},
 61         {0,             NULL}
 62 };
 63 
 64 
 65 static struct kmem_cache * efs_inode_cachep;
 66 
 67 static struct inode *efs_alloc_inode(struct super_block *sb)
 68 {
 69         struct efs_inode_info *ei;
 70         ei = kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
 71         if (!ei)
 72                 return NULL;
 73         return &ei->vfs_inode;
 74 }
 75 
 76 static void efs_i_callback(struct rcu_head *head)
 77 {
 78         struct inode *inode = container_of(head, struct inode, i_rcu);
 79         kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
 80 }
 81 
 82 static void efs_destroy_inode(struct inode *inode)
 83 {
 84         call_rcu(&inode->i_rcu, efs_i_callback);
 85 }
 86 
 87 static void init_once(void *foo)
 88 {
 89         struct efs_inode_info *ei = (struct efs_inode_info *) foo;
 90 
 91         inode_init_once(&ei->vfs_inode);
 92 }
 93 
 94 static int __init init_inodecache(void)
 95 {
 96         efs_inode_cachep = kmem_cache_create("efs_inode_cache",
 97                                 sizeof(struct efs_inode_info), 0,
 98                                 SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
 99                                 SLAB_ACCOUNT, init_once);
100         if (efs_inode_cachep == NULL)
101                 return -ENOMEM;
102         return 0;
103 }
104 
105 static void destroy_inodecache(void)
106 {
107         /*
108          * Make sure all delayed rcu free inodes are flushed before we
109          * destroy cache.
110          */
111         rcu_barrier();
112         kmem_cache_destroy(efs_inode_cachep);
113 }
114 
115 static int efs_remount(struct super_block *sb, int *flags, char *data)
116 {
117         sync_filesystem(sb);
118         *flags |= MS_RDONLY;
119         return 0;
120 }
121 
122 static const struct super_operations efs_superblock_operations = {
123         .alloc_inode    = efs_alloc_inode,
124         .destroy_inode  = efs_destroy_inode,
125         .statfs         = efs_statfs,
126         .remount_fs     = efs_remount,
127 };
128 
129 static const struct export_operations efs_export_ops = {
130         .fh_to_dentry   = efs_fh_to_dentry,
131         .fh_to_parent   = efs_fh_to_parent,
132         .get_parent     = efs_get_parent,
133 };
134 
135 static int __init init_efs_fs(void) {
136         int err;
137         pr_info(EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
138         err = init_inodecache();
139         if (err)
140                 goto out1;
141         err = register_filesystem(&efs_fs_type);
142         if (err)
143                 goto out;
144         return 0;
145 out:
146         destroy_inodecache();
147 out1:
148         return err;
149 }
150 
151 static void __exit exit_efs_fs(void) {
152         unregister_filesystem(&efs_fs_type);
153         destroy_inodecache();
154 }
155 
156 module_init(init_efs_fs)
157 module_exit(exit_efs_fs)
158 
159 static efs_block_t efs_validate_vh(struct volume_header *vh) {
160         int             i;
161         __be32          cs, *ui;
162         int             csum;
163         efs_block_t     sblock = 0; /* shuts up gcc */
164         struct pt_types *pt_entry;
165         int             pt_type, slice = -1;
166 
167         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
168                 /*
169                  * assume that we're dealing with a partition and allow
170                  * read_super() to try and detect a valid superblock
171                  * on the next block.
172                  */
173                 return 0;
174         }
175 
176         ui = ((__be32 *) (vh + 1)) - 1;
177         for(csum = 0; ui >= ((__be32 *) vh);) {
178                 cs = *ui--;
179                 csum += be32_to_cpu(cs);
180         }
181         if (csum) {
182                 pr_warn("SGI disklabel: checksum bad, label corrupted\n");
183                 return 0;
184         }
185 
186 #ifdef DEBUG
187         pr_debug("bf: \"%16s\"\n", vh->vh_bootfile);
188 
189         for(i = 0; i < NVDIR; i++) {
190                 int     j;
191                 char    name[VDNAMESIZE+1];
192 
193                 for(j = 0; j < VDNAMESIZE; j++) {
194                         name[j] = vh->vh_vd[i].vd_name[j];
195                 }
196                 name[j] = (char) 0;
197 
198                 if (name[0]) {
199                         pr_debug("vh: %8s block: 0x%08x size: 0x%08x\n",
200                                 name, (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
201                                 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
202                 }
203         }
204 #endif
205 
206         for(i = 0; i < NPARTAB; i++) {
207                 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
208                 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
209                         if (pt_type == pt_entry->pt_type) break;
210                 }
211 #ifdef DEBUG
212                 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
213                         pr_debug("pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
214                                  i, (int)be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
215                                  (int)be32_to_cpu(vh->vh_pt[i].pt_nblks),
216                                  pt_type, (pt_entry->pt_name) ?
217                                  pt_entry->pt_name : "unknown");
218                 }
219 #endif
220                 if (IS_EFS(pt_type)) {
221                         sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
222                         slice = i;
223                 }
224         }
225 
226         if (slice == -1) {
227                 pr_notice("partition table contained no EFS partitions\n");
228 #ifdef DEBUG
229         } else {
230                 pr_info("using slice %d (type %s, offset 0x%x)\n", slice,
231                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
232                         sblock);
233 #endif
234         }
235         return sblock;
236 }
237 
238 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
239 
240         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
241                 return -1;
242 
243         sb->fs_magic     = be32_to_cpu(super->fs_magic);
244         sb->total_blocks = be32_to_cpu(super->fs_size);
245         sb->first_block  = be32_to_cpu(super->fs_firstcg);
246         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
247         sb->data_free    = be32_to_cpu(super->fs_tfree);
248         sb->inode_free   = be32_to_cpu(super->fs_tinode);
249         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
250         sb->total_groups = be16_to_cpu(super->fs_ncg);
251     
252         return 0;    
253 }
254 
255 static int efs_fill_super(struct super_block *s, void *d, int silent)
256 {
257         struct efs_sb_info *sb;
258         struct buffer_head *bh;
259         struct inode *root;
260 
261         sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
262         if (!sb)
263                 return -ENOMEM;
264         s->s_fs_info = sb;
265  
266         s->s_magic              = EFS_SUPER_MAGIC;
267         if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
268                 pr_err("device does not support %d byte blocks\n",
269                         EFS_BLOCKSIZE);
270                 return -EINVAL;
271         }
272   
273         /* read the vh (volume header) block */
274         bh = sb_bread(s, 0);
275 
276         if (!bh) {
277                 pr_err("cannot read volume header\n");
278                 return -EINVAL;
279         }
280 
281         /*
282          * if this returns zero then we didn't find any partition table.
283          * this isn't (yet) an error - just assume for the moment that
284          * the device is valid and go on to search for a superblock.
285          */
286         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
287         brelse(bh);
288 
289         if (sb->fs_start == -1) {
290                 return -EINVAL;
291         }
292 
293         bh = sb_bread(s, sb->fs_start + EFS_SUPER);
294         if (!bh) {
295                 pr_err("cannot read superblock\n");
296                 return -EINVAL;
297         }
298                 
299         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
300 #ifdef DEBUG
301                 pr_warn("invalid superblock at block %u\n",
302                         sb->fs_start + EFS_SUPER);
303 #endif
304                 brelse(bh);
305                 return -EINVAL;
306         }
307         brelse(bh);
308 
309         if (!(s->s_flags & MS_RDONLY)) {
310 #ifdef DEBUG
311                 pr_info("forcing read-only mode\n");
312 #endif
313                 s->s_flags |= MS_RDONLY;
314         }
315         s->s_op   = &efs_superblock_operations;
316         s->s_export_op = &efs_export_ops;
317         root = efs_iget(s, EFS_ROOTINODE);
318         if (IS_ERR(root)) {
319                 pr_err("get root inode failed\n");
320                 return PTR_ERR(root);
321         }
322 
323         s->s_root = d_make_root(root);
324         if (!(s->s_root)) {
325                 pr_err("get root dentry failed\n");
326                 return -ENOMEM;
327         }
328 
329         return 0;
330 }
331 
332 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
333         struct super_block *sb = dentry->d_sb;
334         struct efs_sb_info *sbi = SUPER_INFO(sb);
335         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
336 
337         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
338         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
339         buf->f_blocks  = sbi->total_groups *    /* total data blocks */
340                         (sbi->group_size - sbi->inode_blocks);
341         buf->f_bfree   = sbi->data_free;        /* free data blocks */
342         buf->f_bavail  = sbi->data_free;        /* free blocks for non-root */
343         buf->f_files   = sbi->total_groups *    /* total inodes */
344                         sbi->inode_blocks *
345                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
346         buf->f_ffree   = sbi->inode_free;       /* free inodes */
347         buf->f_fsid.val[0] = (u32)id;
348         buf->f_fsid.val[1] = (u32)(id >> 32);
349         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
350 
351         return 0;
352 }
353 
354 

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