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1.1 root 1: /*
1.1.1.2 root 2: * linux/fs/super.c
3: *
4: * (C) 1991 Linus Torvalds
5: */
6:
7: /*
1.1 root 8: * super.c contains code to handle the super-block tables.
9: */
10: #include <linux/config.h>
11: #include <linux/sched.h>
12: #include <linux/kernel.h>
1.1.1.2 root 13: #include <asm/system.h>
14:
15: #include <errno.h>
16: #include <sys/stat.h>
17:
18: int sync_dev(int dev);
19: void wait_for_keypress(void);
1.1 root 20:
21: /* set_bit uses setb, as gas doesn't recognize setc */
22: #define set_bit(bitnr,addr) ({ \
23: register int __res __asm__("ax"); \
24: __asm__("bt %2,%3;setb %%al":"=a" (__res):"a" (0),"r" (bitnr),"m" (*(addr))); \
25: __res; })
26:
27: struct super_block super_block[NR_SUPER];
1.1.1.2 root 28: /* this is initialized in init/main.c */
29: int ROOT_DEV = 0;
1.1 root 30:
1.1.1.2 root 31: static void lock_super(struct super_block * sb)
1.1 root 32: {
1.1.1.2 root 33: cli();
34: while (sb->s_lock)
35: sleep_on(&(sb->s_wait));
36: sb->s_lock = 1;
37: sti();
38: }
39:
40: static void free_super(struct super_block * sb)
41: {
42: cli();
43: sb->s_lock = 0;
44: wake_up(&(sb->s_wait));
45: sti();
46: }
47:
48: static void wait_on_super(struct super_block * sb)
49: {
50: cli();
51: while (sb->s_lock)
52: sleep_on(&(sb->s_wait));
53: sti();
54: }
55:
56: struct super_block * get_super(int dev)
57: {
58: struct super_block * s;
59:
60: if (!dev)
61: return NULL;
62: s = 0+super_block;
63: while (s < NR_SUPER+super_block)
64: if (s->s_dev == dev) {
65: wait_on_super(s);
66: if (s->s_dev == dev)
67: return s;
68: s = 0+super_block;
69: } else
70: s++;
71: return NULL;
72: }
73:
74: void put_super(int dev)
75: {
76: struct super_block * sb;
77: int i;
78:
79: if (dev == ROOT_DEV) {
80: printk("root diskette changed: prepare for armageddon\n\r");
81: return;
82: }
83: if (!(sb = get_super(dev)))
84: return;
85: if (sb->s_imount) {
86: printk("Mounted disk changed - tssk, tssk\n\r");
87: return;
88: }
89: lock_super(sb);
90: sb->s_dev = 0;
91: for(i=0;i<I_MAP_SLOTS;i++)
92: brelse(sb->s_imap[i]);
93: for(i=0;i<Z_MAP_SLOTS;i++)
94: brelse(sb->s_zmap[i]);
95: free_super(sb);
96: return;
97: }
98:
99: static struct super_block * read_super(int dev)
100: {
101: struct super_block * s;
1.1 root 102: struct buffer_head * bh;
103: int i,block;
104:
1.1.1.2 root 105: if (!dev)
1.1 root 106: return NULL;
1.1.1.2 root 107: check_disk_change(dev);
108: if (s = get_super(dev))
109: return s;
110: for (s = 0+super_block ;; s++) {
111: if (s >= NR_SUPER+super_block)
112: return NULL;
113: if (!s->s_dev)
114: break;
115: }
116: s->s_dev = dev;
117: s->s_isup = NULL;
118: s->s_imount = NULL;
119: s->s_time = 0;
120: s->s_rd_only = 0;
121: s->s_dirt = 0;
122: lock_super(s);
123: if (!(bh = bread(dev,1))) {
124: s->s_dev=0;
125: free_super(s);
1.1 root 126: return NULL;
1.1.1.2 root 127: }
128: *((struct d_super_block *) s) =
129: *((struct d_super_block *) bh->b_data);
1.1 root 130: brelse(bh);
1.1.1.2 root 131: if (s->s_magic != SUPER_MAGIC) {
132: s->s_dev = 0;
133: free_super(s);
1.1 root 134: return NULL;
135: }
136: for (i=0;i<I_MAP_SLOTS;i++)
1.1.1.2 root 137: s->s_imap[i] = NULL;
1.1 root 138: for (i=0;i<Z_MAP_SLOTS;i++)
1.1.1.2 root 139: s->s_zmap[i] = NULL;
1.1 root 140: block=2;
1.1.1.2 root 141: for (i=0 ; i < s->s_imap_blocks ; i++)
142: if (s->s_imap[i]=bread(dev,block))
1.1 root 143: block++;
144: else
145: break;
1.1.1.2 root 146: for (i=0 ; i < s->s_zmap_blocks ; i++)
147: if (s->s_zmap[i]=bread(dev,block))
1.1 root 148: block++;
149: else
150: break;
1.1.1.2 root 151: if (block != 2+s->s_imap_blocks+s->s_zmap_blocks) {
1.1 root 152: for(i=0;i<I_MAP_SLOTS;i++)
1.1.1.2 root 153: brelse(s->s_imap[i]);
1.1 root 154: for(i=0;i<Z_MAP_SLOTS;i++)
1.1.1.2 root 155: brelse(s->s_zmap[i]);
156: s->s_dev=0;
157: free_super(s);
1.1 root 158: return NULL;
159: }
1.1.1.2 root 160: s->s_imap[0]->b_data[0] |= 1;
161: s->s_zmap[0]->b_data[0] |= 1;
162: free_super(s);
163: return s;
164: }
165:
166: int sys_umount(char * dev_name)
167: {
168: struct m_inode * inode;
169: struct super_block * sb;
170: int dev;
171:
172: if (!(inode=namei(dev_name)))
173: return -ENOENT;
174: dev = inode->i_zone[0];
175: if (!S_ISBLK(inode->i_mode)) {
176: iput(inode);
177: return -ENOTBLK;
178: }
179: iput(inode);
180: if (dev==ROOT_DEV)
181: return -EBUSY;
182: if (!(sb=get_super(dev)) || !(sb->s_imount))
183: return -ENOENT;
184: if (!sb->s_imount->i_mount)
185: printk("Mounted inode has i_mount=0\n");
1.1.1.3 root 186: for (inode=inode_table+0 ; inode<inode_table+NR_INODE ; inode++)
1.1.1.2 root 187: if (inode->i_dev==dev && inode->i_count)
1.1.1.3 root 188: return -EBUSY;
1.1.1.2 root 189: sb->s_imount->i_mount=0;
190: iput(sb->s_imount);
191: sb->s_imount = NULL;
192: iput(sb->s_isup);
193: sb->s_isup = NULL;
194: put_super(dev);
195: sync_dev(dev);
196: return 0;
197: }
198:
199: int sys_mount(char * dev_name, char * dir_name, int rw_flag)
200: {
201: struct m_inode * dev_i, * dir_i;
202: struct super_block * sb;
203: int dev;
204:
205: if (!(dev_i=namei(dev_name)))
206: return -ENOENT;
207: dev = dev_i->i_zone[0];
208: if (!S_ISBLK(dev_i->i_mode)) {
209: iput(dev_i);
210: return -EPERM;
211: }
212: iput(dev_i);
213: if (!(dir_i=namei(dir_name)))
214: return -ENOENT;
215: if (dir_i->i_count != 1 || dir_i->i_num == ROOT_INO) {
216: iput(dir_i);
217: return -EBUSY;
218: }
219: if (!S_ISDIR(dir_i->i_mode)) {
220: iput(dir_i);
221: return -EPERM;
222: }
223: if (!(sb=read_super(dev))) {
224: iput(dir_i);
225: return -EBUSY;
226: }
227: if (sb->s_imount) {
228: iput(dir_i);
229: return -EBUSY;
230: }
231: if (dir_i->i_mount) {
232: iput(dir_i);
233: return -EPERM;
234: }
235: sb->s_imount=dir_i;
236: dir_i->i_mount=1;
237: dir_i->i_dirt=1; /* NOTE! we don't iput(dir_i) */
238: return 0; /* we do that in umount */
1.1 root 239: }
240:
241: void mount_root(void)
242: {
243: int i,free;
244: struct super_block * p;
245: struct m_inode * mi;
246:
247: if (32 != sizeof (struct d_inode))
248: panic("bad i-node size");
249: for(i=0;i<NR_FILE;i++)
250: file_table[i].f_count=0;
1.1.1.2 root 251: if (MAJOR(ROOT_DEV) == 2) {
252: printk("Insert root floppy and press ENTER");
253: wait_for_keypress();
254: }
255: for(p = &super_block[0] ; p < &super_block[NR_SUPER] ; p++) {
1.1 root 256: p->s_dev = 0;
1.1.1.2 root 257: p->s_lock = 0;
258: p->s_wait = NULL;
259: }
260: if (!(p=read_super(ROOT_DEV)))
1.1 root 261: panic("Unable to mount root");
1.1.1.2 root 262: if (!(mi=iget(ROOT_DEV,ROOT_INO)))
1.1 root 263: panic("Unable to read root i-node");
264: mi->i_count += 3 ; /* NOTE! it is logically used 4 times, not 1 */
265: p->s_isup = p->s_imount = mi;
266: current->pwd = mi;
267: current->root = mi;
268: free=0;
269: i=p->s_nzones;
270: while (-- i >= 0)
271: if (!set_bit(i&8191,p->s_zmap[i>>13]->b_data))
272: free++;
273: printk("%d/%d free blocks\n\r",free,p->s_nzones);
274: free=0;
275: i=p->s_ninodes+1;
276: while (-- i >= 0)
277: if (!set_bit(i&8191,p->s_imap[i>>13]->b_data))
278: free++;
279: printk("%d/%d free inodes\n\r",free,p->s_ninodes);
280: }
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