1 #include <linux/kernel.h>
3 #include <linux/buffer_head.h>
7 unsigned long omfs_count_free(struct super_block
*sb
)
10 unsigned long sum
= 0;
11 struct omfs_sb_info
*sbi
= OMFS_SB(sb
);
12 int nbits
= sb
->s_blocksize
* 8;
14 for (i
= 0; i
< sbi
->s_imap_size
; i
++)
15 sum
+= nbits
- bitmap_weight(sbi
->s_imap
[i
], nbits
);
21 * Counts the run of zero bits starting at bit up to max.
22 * It handles the case where a run might spill over a buffer.
23 * Called with bitmap lock.
25 static int count_run(unsigned long **addr
, int nbits
,
26 int addrlen
, int bit
, int max
)
31 for (; addrlen
> 0; addrlen
--, addr
++) {
32 x
= find_next_bit(*addr
, nbits
, bit
);
35 if (x
< nbits
|| count
> max
)
36 return min(count
, max
);
40 return min(count
, max
);
44 * Sets or clears the run of count bits starting with bit.
45 * Called with bitmap lock.
47 static int set_run(struct super_block
*sb
, int map
,
48 int nbits
, int bit
, int count
, int set
)
52 struct buffer_head
*bh
;
53 struct omfs_sb_info
*sbi
= OMFS_SB(sb
);
56 bh
= sb_bread(sb
, clus_to_blk(sbi
, sbi
->s_bitmap_ino
) + map
);
60 for (i
= 0; i
< count
; i
++, bit
++) {
65 mark_buffer_dirty(bh
);
68 clus_to_blk(sbi
, sbi
->s_bitmap_ino
) + map
);
73 set_bit(bit
, sbi
->s_imap
[map
]);
74 set_bit(bit
, (unsigned long *)bh
->b_data
);
76 clear_bit(bit
, sbi
->s_imap
[map
]);
77 clear_bit(bit
, (unsigned long *)bh
->b_data
);
80 mark_buffer_dirty(bh
);
88 * Tries to allocate exactly one block. Returns true if successful.
90 int omfs_allocate_block(struct super_block
*sb
, u64 block
)
92 struct buffer_head
*bh
;
93 struct omfs_sb_info
*sbi
= OMFS_SB(sb
);
94 int bits_per_entry
= 8 * sb
->s_blocksize
;
95 unsigned int map
, bit
;
100 bit
= do_div(tmp
, bits_per_entry
);
103 mutex_lock(&sbi
->s_bitmap_lock
);
104 if (map
>= sbi
->s_imap_size
|| test_and_set_bit(bit
, sbi
->s_imap
[map
]))
107 if (sbi
->s_bitmap_ino
> 0) {
108 bh
= sb_bread(sb
, clus_to_blk(sbi
, sbi
->s_bitmap_ino
) + map
);
112 set_bit(bit
, (unsigned long *)bh
->b_data
);
113 mark_buffer_dirty(bh
);
118 mutex_unlock(&sbi
->s_bitmap_lock
);
124 * Tries to allocate a set of blocks. The request size depends on the
125 * type: for inodes, we must allocate sbi->s_mirrors blocks, and for file
126 * blocks, we try to allocate sbi->s_clustersize, but can always get away
127 * with just one block.
129 int omfs_allocate_range(struct super_block
*sb
,
135 struct omfs_sb_info
*sbi
= OMFS_SB(sb
);
136 int bits_per_entry
= 8 * sb
->s_blocksize
;
140 mutex_lock(&sbi
->s_bitmap_lock
);
141 for (i
= 0; i
< sbi
->s_imap_size
; i
++) {
143 while (bit
< bits_per_entry
) {
144 bit
= find_next_zero_bit(sbi
->s_imap
[i
], bits_per_entry
,
147 if (bit
== bits_per_entry
)
150 run
= count_run(&sbi
->s_imap
[i
], bits_per_entry
,
151 sbi
->s_imap_size
-i
, bit
, max_request
);
153 if (run
>= min_request
)
162 *return_block
= (u64
) i
* bits_per_entry
+ bit
;
164 ret
= set_run(sb
, i
, bits_per_entry
, bit
, run
, 1);
167 mutex_unlock(&sbi
->s_bitmap_lock
);
172 * Clears count bits starting at a given block.
174 int omfs_clear_range(struct super_block
*sb
, u64 block
, int count
)
176 struct omfs_sb_info
*sbi
= OMFS_SB(sb
);
177 int bits_per_entry
= 8 * sb
->s_blocksize
;
179 unsigned int map
, bit
;
183 bit
= do_div(tmp
, bits_per_entry
);
186 if (map
>= sbi
->s_imap_size
)
189 mutex_lock(&sbi
->s_bitmap_lock
);
190 ret
= set_run(sb
, map
, bits_per_entry
, bit
, count
, 0);
191 mutex_unlock(&sbi
->s_bitmap_lock
);
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