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1.1 root 1: /*
2: * linux/fs/msdos/inode.c
3: *
4: * Written 1992 by Werner Almesberger
5: */
6:
7: #include <linux/msdos_fs.h>
8: #include <linux/kernel.h>
9: #include <linux/sched.h>
10: #include <linux/errno.h>
11: #include <linux/string.h>
12: #include <linux/stat.h>
13:
14: #include <asm/segment.h>
15:
16: void msdos_put_inode(struct inode *inode)
17: {
18: struct inode *depend;
19:
20: inode->i_size = 0;
21: msdos_truncate(inode);
22: depend = (struct inode *) inode->i_data[D_DEPEND];
23: memset(inode,0,sizeof(struct inode));
24: if (depend) {
25: if ((struct inode *) depend->i_data[D_OLD] != inode) {
26: printk("Invalid link (0x%X): expected 0x%X, got "
27: "0x%X\r\n",(int) depend,(int) inode,
28: depend->i_data[D_OLD]);
29: panic("That's fatal");
30: }
31: depend->i_data[D_OLD] = 0;
32: iput(depend);
33: }
34: }
35:
36:
37: void msdos_put_super(struct super_block *sb)
38: {
39: cache_inval_dev(sb->s_dev);
40: lock_super(sb);
41: sb->s_dev = 0;
42: free_super(sb);
43: return;
44: }
45:
46:
47: static struct super_operations msdos_sops = {
48: msdos_read_inode,
49: msdos_write_inode,
50: msdos_put_inode,
51: msdos_put_super,
52: NULL, /* added in 0.96c */
53: msdos_statfs
54: };
55:
56:
57: static int parse_options(char *options,char *check,char *conversion)
58: {
59: char *this,*value;
60:
61: *check = 'n';
62: *conversion = 'b';
63: if (!options) return 1;
64: for (this = strtok(options,","); this; this = strtok(NULL,",")) {
65: if (value = strchr(this,'=')) *value++ = 0;
66: if (!strcmp(this,"check") && value) {
67: if (value[0] && !value[1] && strchr("rns",*value))
68: *check = *value;
69: else if (!strcmp(value,"relaxed")) *check = 'r';
70: else if (!strcmp(value,"normal")) *check = 'n';
71: else if (!strcmp(value,"strict")) *check = 's';
72: else return 0;
73: }
74: else if (!strcmp(this,"conv") && value) {
75: if (value[0] && !value[1] && strchr("bta",*value))
76: *conversion = *value;
77: else if (!strcmp(value,"binary")) *conversion = 'b';
78: else if (!strcmp(value,"text")) *conversion = 't';
79: else if (!strcmp(value,"auto")) *conversion = 'a';
80: else return 0;
81: }
82: else return 0;
83: }
84: return 1;
85: }
86:
87:
88: /* Read the super block of an MS-DOS FS. */
89:
90: struct super_block *msdos_read_super(struct super_block *s,void *data)
91: {
92: struct buffer_head *bh;
93: struct msdos_boot_sector *b;
94: int data_sectors;
95: char check,conversion;
96:
97: if (!parse_options((char *) data,&check,&conversion)) {
98: s->s_dev = 0;
99: return NULL;
100: }
101: cache_init();
102: lock_super(s);
103: bh = bread(s->s_dev, 0, BLOCK_SIZE);
104: free_super(s);
105: if (bh == NULL) {
106: s->s_dev = 0;
107: printk("MSDOS bread failed\r\n");
108: return NULL;
109: }
110: b = (struct msdos_boot_sector *) bh->b_data;
111: s->s_blocksize = 1024; /* we cannot handle anything else yet */
112: MSDOS_SB(s)->cluster_size = b->cluster_size;
113: MSDOS_SB(s)->fats = b->fats;
114: MSDOS_SB(s)->fat_start = b->reserved;
115: MSDOS_SB(s)->fat_length = b->fat_length;
116: MSDOS_SB(s)->dir_start = b->reserved+b->fats*b->fat_length;
117: MSDOS_SB(s)->dir_entries = *((unsigned short *) &b->dir_entries);
118: MSDOS_SB(s)->data_start = MSDOS_SB(s)->dir_start+((MSDOS_SB(s)->
119: dir_entries << 5) >> 9);
120: data_sectors = (*((unsigned short *) &b->sectors) ? *((unsigned short *)
121: &b->sectors) : b->total_sect)-MSDOS_SB(s)->data_start;
122: MSDOS_SB(s)->clusters = b->cluster_size ? data_sectors/b->cluster_size :
123: 0;
124: MSDOS_SB(s)->fat_bits = MSDOS_SB(s)->clusters > MSDOS_FAT12 ? 16 : 12;
125: brelse(bh);
126: printk("[MS-DOS FS Rel. alpha.6, FAT %d, check=%c, conv=%c]\r\n",
127: MSDOS_SB(s)->fat_bits,check,conversion);
128: printk("[me=0x%x,cs=%d,#f=%d,fs=%d,fl=%d,ds=%d,de=%d,data=%d,se=%d,ts=%d]\r\n",
129: b->media,MSDOS_SB(s)->cluster_size,MSDOS_SB(s)->fats,MSDOS_SB(s)->fat_start,
130: MSDOS_SB(s)->fat_length,MSDOS_SB(s)->dir_start,MSDOS_SB(s)->dir_entries,
131: MSDOS_SB(s)->data_start,*(unsigned short *) &b->sectors,b->total_sect);
132: if (!MSDOS_SB(s)->fats || (MSDOS_SB(s)->dir_entries & (MSDOS_DPS-1))
133: || !b->cluster_size || MSDOS_SB(s)->clusters+2 > MSDOS_SB(s)->
134: fat_length*SECTOR_SIZE*8/MSDOS_SB(s)->fat_bits) {
135: s->s_dev = 0;
136: printk("Unsupported FS parameters\r\n");
137: return NULL;
138: }
139: if (!MSDOS_CAN_BMAP(MSDOS_SB(s))) printk("No bmap support\r\n");
140: s->s_magic = MSDOS_SUPER_MAGIC;
141: MSDOS_SB(s)->name_check = check;
142: MSDOS_SB(s)->conversion = conversion;
143: /* set up enough so that it can read an inode */
144: s->s_op = &msdos_sops;
145: MSDOS_SB(s)->fs_uid = current->uid;
146: MSDOS_SB(s)->fs_gid = current->gid;
147: MSDOS_SB(s)->fs_umask = current->umask;
148: if (!(s->s_mounted = iget(s->s_dev,MSDOS_ROOT_INO))) {
149: s->s_dev = 0;
150: printk("get root inode failed\n");
151: return NULL;
152: }
153: return s;
154: }
155:
156:
157: void msdos_statfs(struct super_block *sb,struct statfs *buf)
158: {
159: int cluster_size,free,this;
160:
161: cluster_size = MSDOS_SB(sb)->cluster_size;
162: put_fs_long(sb->s_magic,&buf->f_type);
163: put_fs_long(SECTOR_SIZE,&buf->f_bsize);
164: put_fs_long(MSDOS_SB(sb)->clusters*cluster_size,&buf->f_blocks);
165: free = 0;
166: for (this = 2; this < MSDOS_SB(sb)->clusters+2; this++)
167: if (!fat_access(sb,this,-1)) free++;
168: free *= cluster_size;
169: put_fs_long(free,&buf->f_bfree);
170: put_fs_long(free,&buf->f_bavail);
171: put_fs_long(0,&buf->f_files);
172: put_fs_long(0,&buf->f_ffree);
173: }
174:
175:
176: int msdos_bmap(struct inode *inode,int block)
177: {
178: struct msdos_sb_info *sb;
179: int cluster,offset;
180:
181: sb = MSDOS_SB(inode->i_sb);
182: if ((sb->cluster_size & 1) || (sb->data_start & 1)) return 0;
183: if (inode->i_ino == MSDOS_ROOT_INO) {
184: if (sb->dir_start & 1) return 0;
185: return (sb->dir_start >> 1)+block;
186: }
187: cluster = (block*2)/sb->cluster_size;
188: offset = (block*2) % sb->cluster_size;
189: if (!(cluster = get_cluster(inode,cluster))) return 0;
190: return ((cluster-2)*sb->cluster_size+sb->data_start+offset) >> 1;
191: }
192:
193:
194: void msdos_read_inode(struct inode *inode)
195: {
196: struct buffer_head *bh;
197: struct msdos_dir_entry *raw_entry;
198: int this;
199:
200: /* printk("read inode %d\r\n",inode->i_ino); */
201: inode->i_data[D_BUSY] = inode->i_data[D_DEPEND] =
202: inode->i_data[D_OLD] = 0;
203: inode->i_data[D_BINARY] = 1;
204: inode->i_uid = MSDOS_SB(inode->i_sb)->fs_uid;
205: inode->i_gid = MSDOS_SB(inode->i_sb)->fs_gid;
206: if (inode->i_ino == MSDOS_ROOT_INO) {
207: inode->i_mode = (0777 & ~MSDOS_SB(inode->i_sb)->fs_umask) |
208: S_IFDIR;
209: inode->i_op = &msdos_dir_inode_operations;
210: inode->i_nlink = 1;
211: inode->i_size = MSDOS_SB(inode->i_sb)->dir_entries*
212: sizeof(struct msdos_dir_entry);
213: inode->i_data[D_START] = 0;
214: inode->i_data[D_ATTRS] = 0;
215: inode->i_mtime = inode->i_atime = inode->i_ctime = 0;
216: return;
217: }
218: if (!(bh = bread(inode->i_dev,inode->i_ino >> MSDOS_DPB_BITS, BLOCK_SIZE)))
219: panic("unable to read i-node block");
220: raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
221: [inode->i_ino & (MSDOS_DPB-1)];
222: if (raw_entry->attr & ATTR_DIR) {
223: inode->i_mode = MSDOS_MKMODE(raw_entry->attr,0777 &
224: ~MSDOS_SB(inode->i_sb)->fs_umask) | S_IFDIR;
225: inode->i_op = &msdos_dir_inode_operations;
226: inode->i_nlink = 3;
227: inode->i_size = 0;
228: for (this = raw_entry->start; this && this != -1; this =
229: fat_access(inode->i_sb,this,-1))
230: inode->i_size += SECTOR_SIZE*MSDOS_SB(inode->i_sb)->
231: cluster_size;
232: }
233: else {
234: inode->i_mode = MSDOS_MKMODE(raw_entry->attr,0666 &
235: ~MSDOS_SB(inode->i_sb)->fs_umask) | S_IFREG;
236: inode->i_op = MSDOS_CAN_BMAP(MSDOS_SB(inode->i_sb)) ?
237: &msdos_file_inode_operations :
238: &msdos_file_inode_operations_no_bmap;
239: inode->i_nlink = 1;
240: inode->i_size = raw_entry->size;
241: }
242: inode->i_data[D_BINARY] = is_binary(MSDOS_SB(inode->i_sb)->conversion,
243: raw_entry->ext);
244: inode->i_data[D_START] = raw_entry->start;
245: inode->i_data[D_ATTRS] = raw_entry->attr & ATTR_UNUSED;
246: inode->i_mtime = inode->i_atime = inode->i_ctime =
247: date_dos2unix(raw_entry->time,raw_entry->date);
248: brelse(bh);
249: }
250:
251:
252: void msdos_write_inode(struct inode *inode)
253: {
254: struct buffer_head *bh;
255: struct msdos_dir_entry *raw_entry;
256:
257: inode->i_dirt = 0;
258: if (inode->i_ino == MSDOS_ROOT_INO || !inode->i_nlink) return;
259: if (!(bh = bread(inode->i_dev,inode->i_ino >> MSDOS_DPB_BITS, BLOCK_SIZE)))
260: panic("unable to read i-node block");
261: raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
262: [inode->i_ino & (MSDOS_DPB-1)];
263: if (S_ISDIR(inode->i_mode)) {
264: raw_entry->attr = ATTR_DIR;
265: raw_entry->size = 0;
266: }
267: else {
268: raw_entry->attr = ATTR_NONE;
269: raw_entry->size = inode->i_size;
270: }
271: raw_entry->attr |= MSDOS_MKATTR(inode->i_mode) | inode->i_data[D_ATTRS];
272: raw_entry->start = inode->i_data[D_START];
273: date_unix2dos(inode->i_mtime,&raw_entry->time,&raw_entry->date);
274: bh->b_dirt = 1;
275: brelse(bh);
276: }
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