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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
36cc410a BC |
2 | #include <linux/kernel.h> |
3 | #include <linux/fs.h> | |
4 | #include <linux/buffer_head.h> | |
5 | #include <asm/div64.h> | |
6 | #include "omfs.h" | |
7 | ||
8 | unsigned long omfs_count_free(struct super_block *sb) | |
9 | { | |
10 | unsigned int i; | |
11 | unsigned long sum = 0; | |
12 | struct omfs_sb_info *sbi = OMFS_SB(sb); | |
13 | int nbits = sb->s_blocksize * 8; | |
14 | ||
15 | for (i = 0; i < sbi->s_imap_size; i++) | |
16 | sum += nbits - bitmap_weight(sbi->s_imap[i], nbits); | |
17 | ||
18 | return sum; | |
19 | } | |
20 | ||
21 | /* | |
22 | * Counts the run of zero bits starting at bit up to max. | |
23 | * It handles the case where a run might spill over a buffer. | |
24 | * Called with bitmap lock. | |
25 | */ | |
26 | static int count_run(unsigned long **addr, int nbits, | |
27 | int addrlen, int bit, int max) | |
28 | { | |
29 | int count = 0; | |
30 | int x; | |
31 | ||
32 | for (; addrlen > 0; addrlen--, addr++) { | |
33 | x = find_next_bit(*addr, nbits, bit); | |
34 | count += x - bit; | |
35 | ||
36 | if (x < nbits || count > max) | |
37 | return min(count, max); | |
38 | ||
39 | bit = 0; | |
40 | } | |
41 | return min(count, max); | |
42 | } | |
43 | ||
44 | /* | |
45 | * Sets or clears the run of count bits starting with bit. | |
46 | * Called with bitmap lock. | |
47 | */ | |
48 | static int set_run(struct super_block *sb, int map, | |
49 | int nbits, int bit, int count, int set) | |
50 | { | |
51 | int i; | |
52 | int err; | |
53 | struct buffer_head *bh; | |
54 | struct omfs_sb_info *sbi = OMFS_SB(sb); | |
55 | ||
56 | err = -ENOMEM; | |
57 | bh = sb_bread(sb, clus_to_blk(sbi, sbi->s_bitmap_ino) + map); | |
58 | if (!bh) | |
59 | goto out; | |
60 | ||
61 | for (i = 0; i < count; i++, bit++) { | |
62 | if (bit >= nbits) { | |
63 | bit = 0; | |
64 | map++; | |
65 | ||
66 | mark_buffer_dirty(bh); | |
67 | brelse(bh); | |
68 | bh = sb_bread(sb, | |
69 | clus_to_blk(sbi, sbi->s_bitmap_ino) + map); | |
70 | if (!bh) | |
71 | goto out; | |
72 | } | |
73 | if (set) { | |
74 | set_bit(bit, sbi->s_imap[map]); | |
d406f66d | 75 | set_bit(bit, (unsigned long *)bh->b_data); |
36cc410a BC |
76 | } else { |
77 | clear_bit(bit, sbi->s_imap[map]); | |
d406f66d | 78 | clear_bit(bit, (unsigned long *)bh->b_data); |
36cc410a BC |
79 | } |
80 | } | |
81 | mark_buffer_dirty(bh); | |
82 | brelse(bh); | |
83 | err = 0; | |
84 | out: | |
85 | return err; | |
86 | } | |
87 | ||
88 | /* | |
af901ca1 | 89 | * Tries to allocate exactly one block. Returns true if successful. |
36cc410a BC |
90 | */ |
91 | int omfs_allocate_block(struct super_block *sb, u64 block) | |
92 | { | |
93 | struct buffer_head *bh; | |
94 | struct omfs_sb_info *sbi = OMFS_SB(sb); | |
95 | int bits_per_entry = 8 * sb->s_blocksize; | |
9419fc1c | 96 | unsigned int map, bit; |
36cc410a BC |
97 | int ret = 0; |
98 | u64 tmp; | |
99 | ||
100 | tmp = block; | |
101 | bit = do_div(tmp, bits_per_entry); | |
102 | map = tmp; | |
103 | ||
104 | mutex_lock(&sbi->s_bitmap_lock); | |
105 | if (map >= sbi->s_imap_size || test_and_set_bit(bit, sbi->s_imap[map])) | |
106 | goto out; | |
107 | ||
108 | if (sbi->s_bitmap_ino > 0) { | |
109 | bh = sb_bread(sb, clus_to_blk(sbi, sbi->s_bitmap_ino) + map); | |
110 | if (!bh) | |
111 | goto out; | |
112 | ||
d406f66d | 113 | set_bit(bit, (unsigned long *)bh->b_data); |
36cc410a BC |
114 | mark_buffer_dirty(bh); |
115 | brelse(bh); | |
116 | } | |
117 | ret = 1; | |
118 | out: | |
119 | mutex_unlock(&sbi->s_bitmap_lock); | |
120 | return ret; | |
121 | } | |
122 | ||
123 | ||
124 | /* | |
125 | * Tries to allocate a set of blocks. The request size depends on the | |
126 | * type: for inodes, we must allocate sbi->s_mirrors blocks, and for file | |
127 | * blocks, we try to allocate sbi->s_clustersize, but can always get away | |
128 | * with just one block. | |
129 | */ | |
130 | int omfs_allocate_range(struct super_block *sb, | |
131 | int min_request, | |
132 | int max_request, | |
133 | u64 *return_block, | |
134 | int *return_size) | |
135 | { | |
136 | struct omfs_sb_info *sbi = OMFS_SB(sb); | |
137 | int bits_per_entry = 8 * sb->s_blocksize; | |
138 | int ret = 0; | |
139 | int i, run, bit; | |
140 | ||
141 | mutex_lock(&sbi->s_bitmap_lock); | |
142 | for (i = 0; i < sbi->s_imap_size; i++) { | |
143 | bit = 0; | |
144 | while (bit < bits_per_entry) { | |
145 | bit = find_next_zero_bit(sbi->s_imap[i], bits_per_entry, | |
146 | bit); | |
147 | ||
148 | if (bit == bits_per_entry) | |
149 | break; | |
150 | ||
151 | run = count_run(&sbi->s_imap[i], bits_per_entry, | |
152 | sbi->s_imap_size-i, bit, max_request); | |
153 | ||
154 | if (run >= min_request) | |
155 | goto found; | |
156 | bit += run; | |
157 | } | |
158 | } | |
159 | ret = -ENOSPC; | |
160 | goto out; | |
161 | ||
162 | found: | |
5a6b2b36 | 163 | *return_block = (u64) i * bits_per_entry + bit; |
36cc410a BC |
164 | *return_size = run; |
165 | ret = set_run(sb, i, bits_per_entry, bit, run, 1); | |
166 | ||
167 | out: | |
168 | mutex_unlock(&sbi->s_bitmap_lock); | |
169 | return ret; | |
170 | } | |
171 | ||
172 | /* | |
173 | * Clears count bits starting at a given block. | |
174 | */ | |
175 | int omfs_clear_range(struct super_block *sb, u64 block, int count) | |
176 | { | |
177 | struct omfs_sb_info *sbi = OMFS_SB(sb); | |
178 | int bits_per_entry = 8 * sb->s_blocksize; | |
179 | u64 tmp; | |
9419fc1c BC |
180 | unsigned int map, bit; |
181 | int ret; | |
36cc410a BC |
182 | |
183 | tmp = block; | |
184 | bit = do_div(tmp, bits_per_entry); | |
185 | map = tmp; | |
186 | ||
187 | if (map >= sbi->s_imap_size) | |
188 | return 0; | |
189 | ||
190 | mutex_lock(&sbi->s_bitmap_lock); | |
191 | ret = set_run(sb, map, bits_per_entry, bit, count, 0); | |
192 | mutex_unlock(&sbi->s_bitmap_lock); | |
193 | return ret; | |
194 | } |