Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
This commit is contained in:
Linus Torvalds
221
fs/hfsplus/bitmap.c
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221
fs/hfsplus/bitmap.c
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/*
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* linux/fs/hfsplus/bitmap.c
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*
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* Copyright (C) 2001
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* Brad Boyer (flar@allandria.com)
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* (C) 2003 Ardis Technologies <roman@ardistech.com>
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*
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* Handling of allocation file
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*/
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#include <linux/pagemap.h>
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#include "hfsplus_fs.h"
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#include "hfsplus_raw.h"
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#define PAGE_CACHE_BITS (PAGE_CACHE_SIZE * 8)
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int hfsplus_block_allocate(struct super_block *sb, u32 size, u32 offset, u32 *max)
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{
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struct page *page;
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struct address_space *mapping;
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__be32 *pptr, *curr, *end;
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u32 mask, start, len, n;
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__be32 val;
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int i;
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len = *max;
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if (!len)
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return size;
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dprint(DBG_BITMAP, "block_allocate: %u,%u,%u\n", size, offset, len);
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down(&HFSPLUS_SB(sb).alloc_file->i_sem);
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mapping = HFSPLUS_SB(sb).alloc_file->i_mapping;
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page = read_cache_page(mapping, offset / PAGE_CACHE_BITS,
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(filler_t *)mapping->a_ops->readpage, NULL);
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pptr = kmap(page);
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curr = pptr + (offset & (PAGE_CACHE_BITS - 1)) / 32;
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i = offset % 32;
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offset &= ~(PAGE_CACHE_BITS - 1);
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if ((size ^ offset) / PAGE_CACHE_BITS)
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end = pptr + PAGE_CACHE_BITS / 32;
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else
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end = pptr + ((size + 31) & (PAGE_CACHE_BITS - 1)) / 32;
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/* scan the first partial u32 for zero bits */
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val = *curr;
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if (~val) {
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n = be32_to_cpu(val);
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mask = (1U << 31) >> i;
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for (; i < 32; mask >>= 1, i++) {
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if (!(n & mask))
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goto found;
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}
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}
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curr++;
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/* scan complete u32s for the first zero bit */
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while (1) {
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while (curr < end) {
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val = *curr;
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if (~val) {
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n = be32_to_cpu(val);
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mask = 1 << 31;
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for (i = 0; i < 32; mask >>= 1, i++) {
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if (!(n & mask))
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goto found;
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}
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}
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curr++;
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}
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kunmap(page);
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offset += PAGE_CACHE_BITS;
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if (offset >= size)
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break;
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page = read_cache_page(mapping, offset / PAGE_CACHE_BITS,
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(filler_t *)mapping->a_ops->readpage, NULL);
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curr = pptr = kmap(page);
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if ((size ^ offset) / PAGE_CACHE_BITS)
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end = pptr + PAGE_CACHE_BITS / 32;
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else
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end = pptr + ((size + 31) & (PAGE_CACHE_BITS - 1)) / 32;
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}
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dprint(DBG_BITMAP, "bitmap full\n");
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start = size;
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goto out;
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found:
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start = offset + (curr - pptr) * 32 + i;
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if (start >= size) {
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dprint(DBG_BITMAP, "bitmap full\n");
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goto out;
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}
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/* do any partial u32 at the start */
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len = min(size - start, len);
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while (1) {
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n |= mask;
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if (++i >= 32)
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break;
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mask >>= 1;
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if (!--len || n & mask)
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goto done;
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}
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if (!--len)
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goto done;
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*curr++ = cpu_to_be32(n);
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/* do full u32s */
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while (1) {
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while (curr < end) {
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n = be32_to_cpu(*curr);
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if (len < 32)
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goto last;
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if (n) {
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len = 32;
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goto last;
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}
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*curr++ = cpu_to_be32(0xffffffff);
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len -= 32;
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}
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set_page_dirty(page);
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kunmap(page);
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offset += PAGE_CACHE_BITS;
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page = read_cache_page(mapping, offset / PAGE_CACHE_BITS,
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(filler_t *)mapping->a_ops->readpage, NULL);
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pptr = kmap(page);
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curr = pptr;
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end = pptr + PAGE_CACHE_BITS / 32;
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}
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last:
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/* do any partial u32 at end */
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mask = 1U << 31;
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for (i = 0; i < len; i++) {
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if (n & mask)
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break;
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n |= mask;
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mask >>= 1;
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}
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done:
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*curr = cpu_to_be32(n);
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set_page_dirty(page);
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kunmap(page);
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*max = offset + (curr - pptr) * 32 + i - start;
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HFSPLUS_SB(sb).free_blocks -= *max;
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sb->s_dirt = 1;
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dprint(DBG_BITMAP, "-> %u,%u\n", start, *max);
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out:
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up(&HFSPLUS_SB(sb).alloc_file->i_sem);
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return start;
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}
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int hfsplus_block_free(struct super_block *sb, u32 offset, u32 count)
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{
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struct page *page;
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struct address_space *mapping;
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__be32 *pptr, *curr, *end;
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u32 mask, len, pnr;
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int i;
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/* is there any actual work to be done? */
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if (!count)
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return 0;
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dprint(DBG_BITMAP, "block_free: %u,%u\n", offset, count);
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/* are all of the bits in range? */
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if ((offset + count) > HFSPLUS_SB(sb).total_blocks)
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return -2;
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down(&HFSPLUS_SB(sb).alloc_file->i_sem);
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mapping = HFSPLUS_SB(sb).alloc_file->i_mapping;
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pnr = offset / PAGE_CACHE_BITS;
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page = read_cache_page(mapping, pnr, (filler_t *)mapping->a_ops->readpage, NULL);
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pptr = kmap(page);
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curr = pptr + (offset & (PAGE_CACHE_BITS - 1)) / 32;
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end = pptr + PAGE_CACHE_BITS / 32;
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len = count;
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/* do any partial u32 at the start */
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i = offset % 32;
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if (i) {
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int j = 32 - i;
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mask = 0xffffffffU << j;
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if (j > count) {
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mask |= 0xffffffffU >> (i + count);
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*curr++ &= cpu_to_be32(mask);
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goto out;
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}
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*curr++ &= cpu_to_be32(mask);
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count -= j;
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}
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/* do full u32s */
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while (1) {
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while (curr < end) {
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if (count < 32)
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goto done;
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*curr++ = 0;
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count -= 32;
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}
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if (!count)
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break;
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set_page_dirty(page);
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kunmap(page);
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page = read_cache_page(mapping, ++pnr, (filler_t *)mapping->a_ops->readpage, NULL);
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pptr = kmap(page);
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curr = pptr;
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end = pptr + PAGE_CACHE_BITS / 32;
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}
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done:
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/* do any partial u32 at end */
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if (count) {
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mask = 0xffffffffU >> count;
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*curr &= cpu_to_be32(mask);
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}
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out:
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set_page_dirty(page);
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kunmap(page);
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HFSPLUS_SB(sb).free_blocks += len;
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sb->s_dirt = 1;
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up(&HFSPLUS_SB(sb).alloc_file->i_sem);
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return 0;
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}
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