1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * linux/fs/minix/bitmap.c |
4 | * |
5 | * Copyright (C) 1991, 1992 Linus Torvalds |
6 | */ |
7 | |
8 | /* |
9 | * Modified for 680x0 by Hamish Macdonald |
10 | * Fixed for 680x0 by Andreas Schwab |
11 | */ |
12 | |
13 | /* bitmap.c contains the code that handles the inode and block bitmaps */ |
14 | |
15 | #include "minix.h" |
16 | #include <linux/buffer_head.h> |
17 | #include <linux/bitops.h> |
18 | #include <linux/sched.h> |
19 | |
20 | static DEFINE_SPINLOCK(bitmap_lock); |
21 | |
22 | /* |
23 | * bitmap consists of blocks filled with 16bit words |
24 | * bit set == busy, bit clear == free |
25 | * endianness is a mess, but for counting zero bits it really doesn't matter... |
26 | */ |
27 | static __u32 count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits) |
28 | { |
29 | __u32 sum = 0; |
30 | unsigned blocks = DIV_ROUND_UP(numbits, blocksize * 8); |
31 | |
32 | while (blocks--) { |
33 | unsigned words = blocksize / 2; |
34 | __u16 *p = (__u16 *)(*map++)->b_data; |
35 | while (words--) |
36 | sum += 16 - hweight16(*p++); |
37 | } |
38 | |
39 | return sum; |
40 | } |
41 | |
42 | void minix_free_block(struct inode *inode, unsigned long block) |
43 | { |
44 | struct super_block *sb = inode->i_sb; |
45 | struct minix_sb_info *sbi = minix_sb(sb); |
46 | struct buffer_head *bh; |
47 | int k = sb->s_blocksize_bits + 3; |
48 | unsigned long bit, zone; |
49 | |
50 | if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) { |
51 | printk("Trying to free block not in datazone\n" ); |
52 | return; |
53 | } |
54 | zone = block - sbi->s_firstdatazone + 1; |
55 | bit = zone & ((1<<k) - 1); |
56 | zone >>= k; |
57 | if (zone >= sbi->s_zmap_blocks) { |
58 | printk("minix_free_block: nonexistent bitmap buffer\n" ); |
59 | return; |
60 | } |
61 | bh = sbi->s_zmap[zone]; |
62 | spin_lock(lock: &bitmap_lock); |
63 | if (!minix_test_and_clear_bit(nr: bit, addr: bh->b_data)) |
64 | printk("minix_free_block (%s:%lu): bit already cleared\n" , |
65 | sb->s_id, block); |
66 | spin_unlock(lock: &bitmap_lock); |
67 | mark_buffer_dirty(bh); |
68 | return; |
69 | } |
70 | |
71 | int minix_new_block(struct inode * inode) |
72 | { |
73 | struct minix_sb_info *sbi = minix_sb(sb: inode->i_sb); |
74 | int bits_per_zone = 8 * inode->i_sb->s_blocksize; |
75 | int i; |
76 | |
77 | for (i = 0; i < sbi->s_zmap_blocks; i++) { |
78 | struct buffer_head *bh = sbi->s_zmap[i]; |
79 | int j; |
80 | |
81 | spin_lock(lock: &bitmap_lock); |
82 | j = minix_find_first_zero_bit(addr: bh->b_data, size: bits_per_zone); |
83 | if (j < bits_per_zone) { |
84 | minix_set_bit(nr: j, addr: bh->b_data); |
85 | spin_unlock(lock: &bitmap_lock); |
86 | mark_buffer_dirty(bh); |
87 | j += i * bits_per_zone + sbi->s_firstdatazone-1; |
88 | if (j < sbi->s_firstdatazone || j >= sbi->s_nzones) |
89 | break; |
90 | return j; |
91 | } |
92 | spin_unlock(lock: &bitmap_lock); |
93 | } |
94 | return 0; |
95 | } |
96 | |
97 | unsigned long minix_count_free_blocks(struct super_block *sb) |
98 | { |
99 | struct minix_sb_info *sbi = minix_sb(sb); |
100 | u32 bits = sbi->s_nzones - sbi->s_firstdatazone + 1; |
101 | |
102 | return (count_free(map: sbi->s_zmap, blocksize: sb->s_blocksize, numbits: bits) |
103 | << sbi->s_log_zone_size); |
104 | } |
105 | |
106 | struct minix_inode * |
107 | minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) |
108 | { |
109 | int block; |
110 | struct minix_sb_info *sbi = minix_sb(sb); |
111 | struct minix_inode *p; |
112 | |
113 | if (!ino || ino > sbi->s_ninodes) { |
114 | printk("Bad inode number on dev %s: %ld is out of range\n" , |
115 | sb->s_id, (long)ino); |
116 | return NULL; |
117 | } |
118 | ino--; |
119 | block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + |
120 | ino / MINIX_INODES_PER_BLOCK; |
121 | *bh = sb_bread(sb, block); |
122 | if (!*bh) { |
123 | printk("Unable to read inode block\n" ); |
124 | return NULL; |
125 | } |
126 | p = (void *)(*bh)->b_data; |
127 | return p + ino % MINIX_INODES_PER_BLOCK; |
128 | } |
129 | |
130 | struct minix2_inode * |
131 | minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) |
132 | { |
133 | int block; |
134 | struct minix_sb_info *sbi = minix_sb(sb); |
135 | struct minix2_inode *p; |
136 | int minix2_inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode); |
137 | |
138 | *bh = NULL; |
139 | if (!ino || ino > sbi->s_ninodes) { |
140 | printk("Bad inode number on dev %s: %ld is out of range\n" , |
141 | sb->s_id, (long)ino); |
142 | return NULL; |
143 | } |
144 | ino--; |
145 | block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + |
146 | ino / minix2_inodes_per_block; |
147 | *bh = sb_bread(sb, block); |
148 | if (!*bh) { |
149 | printk("Unable to read inode block\n" ); |
150 | return NULL; |
151 | } |
152 | p = (void *)(*bh)->b_data; |
153 | return p + ino % minix2_inodes_per_block; |
154 | } |
155 | |
156 | /* Clear the link count and mode of a deleted inode on disk. */ |
157 | |
158 | static void minix_clear_inode(struct inode *inode) |
159 | { |
160 | struct buffer_head *bh = NULL; |
161 | |
162 | if (INODE_VERSION(inode) == MINIX_V1) { |
163 | struct minix_inode *raw_inode; |
164 | raw_inode = minix_V1_raw_inode(sb: inode->i_sb, ino: inode->i_ino, bh: &bh); |
165 | if (raw_inode) { |
166 | raw_inode->i_nlinks = 0; |
167 | raw_inode->i_mode = 0; |
168 | } |
169 | } else { |
170 | struct minix2_inode *raw_inode; |
171 | raw_inode = minix_V2_raw_inode(sb: inode->i_sb, ino: inode->i_ino, bh: &bh); |
172 | if (raw_inode) { |
173 | raw_inode->i_nlinks = 0; |
174 | raw_inode->i_mode = 0; |
175 | } |
176 | } |
177 | if (bh) { |
178 | mark_buffer_dirty(bh); |
179 | brelse (bh); |
180 | } |
181 | } |
182 | |
183 | void minix_free_inode(struct inode * inode) |
184 | { |
185 | struct super_block *sb = inode->i_sb; |
186 | struct minix_sb_info *sbi = minix_sb(sb: inode->i_sb); |
187 | struct buffer_head *bh; |
188 | int k = sb->s_blocksize_bits + 3; |
189 | unsigned long ino, bit; |
190 | |
191 | ino = inode->i_ino; |
192 | if (ino < 1 || ino > sbi->s_ninodes) { |
193 | printk("minix_free_inode: inode 0 or nonexistent inode\n" ); |
194 | return; |
195 | } |
196 | bit = ino & ((1<<k) - 1); |
197 | ino >>= k; |
198 | if (ino >= sbi->s_imap_blocks) { |
199 | printk("minix_free_inode: nonexistent imap in superblock\n" ); |
200 | return; |
201 | } |
202 | |
203 | minix_clear_inode(inode); /* clear on-disk copy */ |
204 | |
205 | bh = sbi->s_imap[ino]; |
206 | spin_lock(lock: &bitmap_lock); |
207 | if (!minix_test_and_clear_bit(nr: bit, addr: bh->b_data)) |
208 | printk("minix_free_inode: bit %lu already cleared\n" , bit); |
209 | spin_unlock(lock: &bitmap_lock); |
210 | mark_buffer_dirty(bh); |
211 | } |
212 | |
213 | struct inode *minix_new_inode(const struct inode *dir, umode_t mode) |
214 | { |
215 | struct super_block *sb = dir->i_sb; |
216 | struct minix_sb_info *sbi = minix_sb(sb); |
217 | struct inode *inode = new_inode(sb); |
218 | struct buffer_head * bh; |
219 | int bits_per_zone = 8 * sb->s_blocksize; |
220 | unsigned long j; |
221 | int i; |
222 | |
223 | if (!inode) |
224 | return ERR_PTR(error: -ENOMEM); |
225 | j = bits_per_zone; |
226 | bh = NULL; |
227 | spin_lock(lock: &bitmap_lock); |
228 | for (i = 0; i < sbi->s_imap_blocks; i++) { |
229 | bh = sbi->s_imap[i]; |
230 | j = minix_find_first_zero_bit(addr: bh->b_data, size: bits_per_zone); |
231 | if (j < bits_per_zone) |
232 | break; |
233 | } |
234 | if (!bh || j >= bits_per_zone) { |
235 | spin_unlock(lock: &bitmap_lock); |
236 | iput(inode); |
237 | return ERR_PTR(error: -ENOSPC); |
238 | } |
239 | if (minix_test_and_set_bit(nr: j, addr: bh->b_data)) { /* shouldn't happen */ |
240 | spin_unlock(lock: &bitmap_lock); |
241 | printk("minix_new_inode: bit already set\n" ); |
242 | iput(inode); |
243 | return ERR_PTR(error: -ENOSPC); |
244 | } |
245 | spin_unlock(lock: &bitmap_lock); |
246 | mark_buffer_dirty(bh); |
247 | j += i * bits_per_zone; |
248 | if (!j || j > sbi->s_ninodes) { |
249 | iput(inode); |
250 | return ERR_PTR(error: -ENOSPC); |
251 | } |
252 | inode_init_owner(idmap: &nop_mnt_idmap, inode, dir, mode); |
253 | inode->i_ino = j; |
254 | simple_inode_init_ts(inode); |
255 | inode->i_blocks = 0; |
256 | memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u)); |
257 | insert_inode_hash(inode); |
258 | mark_inode_dirty(inode); |
259 | |
260 | return inode; |
261 | } |
262 | |
263 | unsigned long minix_count_free_inodes(struct super_block *sb) |
264 | { |
265 | struct minix_sb_info *sbi = minix_sb(sb); |
266 | u32 bits = sbi->s_ninodes + 1; |
267 | |
268 | return count_free(map: sbi->s_imap, blocksize: sb->s_blocksize, numbits: bits); |
269 | } |
270 | |