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Diffstat (limited to 'fs/minix/bitmap.c')
-rw-r--r--fs/minix/bitmap.c55
1 files changed, 24 insertions, 31 deletions
diff --git a/fs/minix/bitmap.c b/fs/minix/bitmap.c
index 3f32bcb..ef175cb 100644
--- a/fs/minix/bitmap.c
+++ b/fs/minix/bitmap.c
@@ -16,38 +16,26 @@
#include <linux/bitops.h>
#include <linux/sched.h>
-static const int nibblemap[] = { 4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,0 };
-
static DEFINE_SPINLOCK(bitmap_lock);
-static unsigned long count_free(struct buffer_head *map[], unsigned numblocks, __u32 numbits)
+/*
+ * bitmap consists of blocks filled with 16bit words
+ * bit set == busy, bit clear == free
+ * endianness is a mess, but for counting zero bits it really doesn't matter...
+ */
+static __u32 count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits)
{
- unsigned i, j, sum = 0;
- struct buffer_head *bh;
-
- for (i=0; i<numblocks-1; i++) {
- if (!(bh=map[i]))
- return(0);
- for (j=0; j<bh->b_size; j++)
- sum += nibblemap[bh->b_data[j] & 0xf]
- + nibblemap[(bh->b_data[j]>>4) & 0xf];
- }
+ __u32 sum = 0;
+ unsigned blocks = DIV_ROUND_UP(numbits, blocksize * 8);
- if (numblocks==0 || !(bh=map[numblocks-1]))
- return(0);
- i = ((numbits - (numblocks-1) * bh->b_size * 8) / 16) * 2;
- for (j=0; j<i; j++) {
- sum += nibblemap[bh->b_data[j] & 0xf]
- + nibblemap[(bh->b_data[j]>>4) & 0xf];
+ while (blocks--) {
+ unsigned words = blocksize / 2;
+ __u16 *p = (__u16 *)(*map++)->b_data;
+ while (words--)
+ sum += 16 - hweight16(*p++);
}
- i = numbits%16;
- if (i!=0) {
- i = *(__u16 *)(&bh->b_data[j]) | ~((1<<i) - 1);
- sum += nibblemap[i & 0xf] + nibblemap[(i>>4) & 0xf];
- sum += nibblemap[(i>>8) & 0xf] + nibblemap[(i>>12) & 0xf];
- }
- return(sum);
+ return sum;
}
void minix_free_block(struct inode *inode, unsigned long block)
@@ -105,10 +93,12 @@ int minix_new_block(struct inode * inode)
return 0;
}
-unsigned long minix_count_free_blocks(struct minix_sb_info *sbi)
+unsigned long minix_count_free_blocks(struct super_block *sb)
{
- return (count_free(sbi->s_zmap, sbi->s_zmap_blocks,
- sbi->s_nzones - sbi->s_firstdatazone + 1)
+ struct minix_sb_info *sbi = minix_sb(sb);
+ u32 bits = sbi->s_nzones - (sbi->s_firstdatazone + 1);
+
+ return (count_free(sbi->s_zmap, sb->s_blocksize, bits)
<< sbi->s_log_zone_size);
}
@@ -273,7 +263,10 @@ struct inode *minix_new_inode(const struct inode *dir, int mode, int *error)
return inode;
}
-unsigned long minix_count_free_inodes(struct minix_sb_info *sbi)
+unsigned long minix_count_free_inodes(struct super_block *sb)
{
- return count_free(sbi->s_imap, sbi->s_imap_blocks, sbi->s_ninodes + 1);
+ struct minix_sb_info *sbi = minix_sb(sb);
+ u32 bits = sbi->s_ninodes + 1;
+
+ return count_free(sbi->s_imap, sb->s_blocksize, bits);
}