2 * OMFS (as used by RIO Karma) directory operations.
3 * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
4 * Released under GPL v2.
8 #include <linux/ctype.h>
9 #include <linux/buffer_head.h>
12 static int omfs_hash(const char *name, int namelen, int mod)
15 for (i = 0; i < namelen; i++)
16 hash ^= tolower(name[i]) << (i % 24);
21 * Finds the bucket for a given name and reads the containing block;
22 * *ofs is set to the offset of the first list entry.
24 static struct buffer_head *omfs_get_bucket(struct inode *dir,
25 const char *name, int namelen, int *ofs)
27 int nbuckets = (dir->i_size - OMFS_DIR_START)/8;
28 int bucket = omfs_hash(name, namelen, nbuckets);
30 *ofs = OMFS_DIR_START + bucket * 8;
31 return omfs_bread(dir->i_sb, dir->i_ino);
34 static struct buffer_head *omfs_scan_list(struct inode *dir, u64 block,
35 const char *name, int namelen,
38 struct buffer_head *bh;
39 struct omfs_inode *oi;
44 bh = omfs_bread(dir->i_sb, block);
50 oi = (struct omfs_inode *) bh->b_data;
51 if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, block)) {
56 if (strncmp(oi->i_name, name, namelen) == 0)
60 block = be64_to_cpu(oi->i_sibling);
67 static struct buffer_head *omfs_find_entry(struct inode *dir,
68 const char *name, int namelen)
70 struct buffer_head *bh;
74 bh = omfs_get_bucket(dir, name, namelen, &ofs);
78 block = be64_to_cpu(*((__be64 *) &bh->b_data[ofs]));
81 return omfs_scan_list(dir, block, name, namelen, &dummy);
84 int omfs_make_empty(struct inode *inode, struct super_block *sb)
86 struct omfs_sb_info *sbi = OMFS_SB(sb);
87 struct buffer_head *bh;
88 struct omfs_inode *oi;
90 bh = omfs_bread(sb, inode->i_ino);
94 memset(bh->b_data, 0, sizeof(struct omfs_inode));
96 if (inode->i_mode & S_IFDIR) {
97 memset(&bh->b_data[OMFS_DIR_START], 0xff,
98 sbi->s_sys_blocksize - OMFS_DIR_START);
100 omfs_make_empty_table(bh, OMFS_EXTENT_START);
102 oi = (struct omfs_inode *) bh->b_data;
103 oi->i_head.h_self = cpu_to_be64(inode->i_ino);
104 oi->i_sibling = ~cpu_to_be64(0ULL);
106 mark_buffer_dirty(bh);
111 static int omfs_add_link(struct dentry *dentry, struct inode *inode)
113 struct inode *dir = dentry->d_parent->d_inode;
114 const char *name = dentry->d_name.name;
115 int namelen = dentry->d_name.len;
116 struct omfs_inode *oi;
117 struct buffer_head *bh;
122 /* just prepend to head of queue in proper bucket */
123 bh = omfs_get_bucket(dir, name, namelen, &ofs);
127 entry = (__be64 *) &bh->b_data[ofs];
128 block = be64_to_cpu(*entry);
129 *entry = cpu_to_be64(inode->i_ino);
130 mark_buffer_dirty(bh);
133 /* now set the sibling and parent pointers on the new inode */
134 bh = omfs_bread(dir->i_sb, inode->i_ino);
138 oi = (struct omfs_inode *) bh->b_data;
139 memcpy(oi->i_name, name, namelen);
140 memset(oi->i_name + namelen, 0, OMFS_NAMELEN - namelen);
141 oi->i_sibling = cpu_to_be64(block);
142 oi->i_parent = cpu_to_be64(dir->i_ino);
143 mark_buffer_dirty(bh);
146 dir->i_ctime = CURRENT_TIME_SEC;
148 /* mark affected inodes dirty to rebuild checksums */
149 mark_inode_dirty(dir);
150 mark_inode_dirty(inode);
156 static int omfs_delete_entry(struct dentry *dentry)
158 struct inode *dir = dentry->d_parent->d_inode;
160 const char *name = dentry->d_name.name;
161 int namelen = dentry->d_name.len;
162 struct omfs_inode *oi;
163 struct buffer_head *bh, *bh2;
169 /* delete the proper node in the bucket's linked list */
170 bh = omfs_get_bucket(dir, name, namelen, &ofs);
174 entry = (__be64 *) &bh->b_data[ofs];
175 block = be64_to_cpu(*entry);
177 bh2 = omfs_scan_list(dir, block, name, namelen, &prev);
183 oi = (struct omfs_inode *) bh2->b_data;
184 next = oi->i_sibling;
188 /* found in middle of list, get list ptr */
190 bh = omfs_bread(dir->i_sb, prev);
194 oi = (struct omfs_inode *) bh->b_data;
195 entry = &oi->i_sibling;
199 mark_buffer_dirty(bh);
202 dirty = omfs_iget(dir->i_sb, prev);
203 if (!IS_ERR(dirty)) {
204 mark_inode_dirty(dirty);
216 static int omfs_dir_is_empty(struct inode *inode)
218 int nbuckets = (inode->i_size - OMFS_DIR_START) / 8;
219 struct buffer_head *bh;
223 bh = omfs_bread(inode->i_sb, inode->i_ino);
228 ptr = (u64 *) &bh->b_data[OMFS_DIR_START];
230 for (i = 0; i < nbuckets; i++, ptr++)
238 static int omfs_remove(struct inode *dir, struct dentry *dentry)
240 struct inode *inode = dentry->d_inode;
243 if (S_ISDIR(inode->i_mode) && !omfs_dir_is_empty(inode))
246 ret = omfs_delete_entry(dentry);
251 mark_inode_dirty(inode);
252 mark_inode_dirty(dir);
256 static int omfs_add_node(struct inode *dir, struct dentry *dentry, int mode)
259 struct inode *inode = omfs_new_inode(dir, mode);
262 return PTR_ERR(inode);
264 err = omfs_make_empty(inode, dir->i_sb);
268 err = omfs_add_link(dentry, inode);
272 d_instantiate(dentry, inode);
280 static int omfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
282 return omfs_add_node(dir, dentry, mode | S_IFDIR);
285 static int omfs_create(struct inode *dir, struct dentry *dentry, int mode,
286 struct nameidata *nd)
288 return omfs_add_node(dir, dentry, mode | S_IFREG);
291 static struct dentry *omfs_lookup(struct inode *dir, struct dentry *dentry,
292 struct nameidata *nd)
294 struct buffer_head *bh;
295 struct inode *inode = NULL;
297 if (dentry->d_name.len > OMFS_NAMELEN)
298 return ERR_PTR(-ENAMETOOLONG);
300 bh = omfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
302 struct omfs_inode *oi = (struct omfs_inode *)bh->b_data;
303 ino_t ino = be64_to_cpu(oi->i_head.h_self);
305 inode = omfs_iget(dir->i_sb, ino);
307 return ERR_CAST(inode);
309 d_add(dentry, inode);
313 /* sanity check block's self pointer */
314 int omfs_is_bad(struct omfs_sb_info *sbi, struct omfs_header *header,
318 u64 ino = be64_to_cpu(header->h_self);
319 is_bad = ((ino != fsblock) || (ino < sbi->s_root_ino) ||
320 (ino > sbi->s_num_blocks));
323 printk(KERN_WARNING "omfs: bad hash chain detected\n");
328 static int omfs_fill_chain(struct file *filp, void *dirent, filldir_t filldir,
329 u64 fsblock, int hindex)
331 struct inode *dir = filp->f_dentry->d_inode;
332 struct buffer_head *bh;
333 struct omfs_inode *oi;
336 unsigned char d_type;
338 /* follow chain in this bucket */
339 while (fsblock != ~0) {
340 bh = omfs_bread(dir->i_sb, fsblock);
344 oi = (struct omfs_inode *) bh->b_data;
345 if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, fsblock)) {
351 fsblock = be64_to_cpu(oi->i_sibling);
353 /* skip visited nodes */
360 d_type = (oi->i_type == OMFS_DIR) ? DT_DIR : DT_REG;
362 res = filldir(dirent, oi->i_name, strnlen(oi->i_name,
363 OMFS_NAMELEN), filp->f_pos, self, d_type);
372 static int omfs_rename(struct inode *old_dir, struct dentry *old_dentry,
373 struct inode *new_dir, struct dentry *new_dentry)
375 struct inode *new_inode = new_dentry->d_inode;
376 struct inode *old_inode = old_dentry->d_inode;
380 /* overwriting existing file/dir */
381 err = omfs_remove(new_dir, new_dentry);
386 /* since omfs locates files by name, we need to unlink _before_
387 * adding the new link or we won't find the old one */
388 err = omfs_delete_entry(old_dentry);
392 mark_inode_dirty(old_dir);
393 err = omfs_add_link(new_dentry, old_inode);
397 old_inode->i_ctime = CURRENT_TIME_SEC;
398 mark_inode_dirty(old_inode);
403 static int omfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
405 struct inode *dir = filp->f_dentry->d_inode;
406 struct buffer_head *bh;
408 unsigned int hchain, hindex;
413 if (filp->f_pos >> 32)
416 switch ((unsigned long) filp->f_pos) {
418 if (filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR) < 0)
423 if (filldir(dirent, "..", 2, 1,
424 parent_ino(filp->f_dentry), DT_DIR) < 0)
426 filp->f_pos = 1 << 20;
430 nbuckets = (dir->i_size - OMFS_DIR_START) / 8;
432 /* high 12 bits store bucket + 1 and low 20 bits store hash index */
433 hchain = (filp->f_pos >> 20) - 1;
434 hindex = filp->f_pos & 0xfffff;
436 bh = omfs_bread(dir->i_sb, dir->i_ino);
440 offset = OMFS_DIR_START + hchain * 8;
442 for (; hchain < nbuckets; hchain++, offset += 8) {
443 fsblock = be64_to_cpu(*((__be64 *) &bh->b_data[offset]));
445 res = omfs_fill_chain(filp, dirent, filldir, fsblock, hindex);
450 filp->f_pos = (hchain+2) << 20;
459 const struct inode_operations omfs_dir_inops = {
460 .lookup = omfs_lookup,
462 .rename = omfs_rename,
463 .create = omfs_create,
464 .unlink = omfs_remove,
465 .rmdir = omfs_remove,
468 const struct file_operations omfs_dir_operations = {
469 .read = generic_read_dir,
470 .readdir = omfs_readdir,
471 .llseek = generic_file_llseek,