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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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#include <linux/slab.h>#include "affs.h"
u32affs_count_free_blocks(struct super_block *sb){ struct affs_bm_info *bm; u32 free; int i;
pr_debug("%s()\n", __func__);
if (sb_rdonly(sb)) return 0;
mutex_lock(&AFFS_SB(sb)->s_bmlock);
bm = AFFS_SB(sb)->s_bitmap; free = 0; for (i = AFFS_SB(sb)->s_bmap_count; i > 0; bm++, i--) free += bm->bm_free;
mutex_unlock(&AFFS_SB(sb)->s_bmlock);
return free;}
voidaffs_free_block(struct super_block *sb, u32 block){ struct affs_sb_info *sbi = AFFS_SB(sb); struct affs_bm_info *bm; struct buffer_head *bh; u32 blk, bmap, bit, mask, tmp; __be32 *data;
pr_debug("%s(%u)\n", __func__, block);
if (!affs_validblock(sb, block)) goto err_range;
blk = block - sbi->s_reserved; bmap = blk / sbi->s_bmap_bits; bit = blk % sbi->s_bmap_bits; bm = &sbi->s_bitmap[bmap];
mutex_lock(&sbi->s_bmlock);
bh = sbi->s_bmap_bh; if (sbi->s_last_bmap != bmap) { affs_brelse(bh); bh = affs_bread(sb, bm->bm_key); if (!bh) goto err_bh_read; sbi->s_bmap_bh = bh; sbi->s_last_bmap = bmap; }
mask = 1 << (bit & 31); data = (__be32 *)bh->b_data + bit / 32 + 1;
/* mark block free */ tmp = be32_to_cpu(*data); if (tmp & mask) goto err_free; *data = cpu_to_be32(tmp | mask);
/* fix checksum */ tmp = be32_to_cpu(*(__be32 *)bh->b_data); *(__be32 *)bh->b_data = cpu_to_be32(tmp - mask);
mark_buffer_dirty(bh); affs_mark_sb_dirty(sb); bm->bm_free++;
mutex_unlock(&sbi->s_bmlock); return;
err_free: affs_warning(sb,"affs_free_block","Trying to free block %u which is already free", block); mutex_unlock(&sbi->s_bmlock); return;
err_bh_read: affs_error(sb,"affs_free_block","Cannot read bitmap block %u", bm->bm_key); sbi->s_bmap_bh = NULL; sbi->s_last_bmap = ~0; mutex_unlock(&sbi->s_bmlock); return;
err_range: affs_error(sb, "affs_free_block","Block %u outside partition", block);}
/* * Allocate a block in the given allocation zone. * Since we have to byte-swap the bitmap on little-endian * machines, this is rather expensive. Therefore we will * preallocate up to 16 blocks from the same word, if * possible. We are not doing preallocations in the * header zone, though. */
u32affs_alloc_block(struct inode *inode, u32 goal){ struct super_block *sb; struct affs_sb_info *sbi; struct affs_bm_info *bm; struct buffer_head *bh; __be32 *data, *enddata; u32 blk, bmap, bit, mask, mask2, tmp; int i;
sb = inode->i_sb; sbi = AFFS_SB(sb);
pr_debug("balloc(inode=%llu,goal=%u): ", inode->i_ino, goal);
if (AFFS_I(inode)->i_pa_cnt) { pr_debug("%d\n", AFFS_I(inode)->i_lastalloc+1); AFFS_I(inode)->i_pa_cnt--; return ++AFFS_I(inode)->i_lastalloc; }
if (!goal || goal > sbi->s_partition_size) { if (goal) affs_warning(sb, "affs_balloc", "invalid goal %d", goal); //if (!AFFS_I(inode)->i_last_block) // affs_warning(sb, "affs_balloc", "no last alloc block"); goal = sbi->s_reserved; }
blk = goal - sbi->s_reserved; bmap = blk / sbi->s_bmap_bits; bm = &sbi->s_bitmap[bmap];
mutex_lock(&sbi->s_bmlock);
if (bm->bm_free) goto find_bmap_bit;
find_bmap: /* search for the next bmap buffer with free bits */ i = sbi->s_bmap_count; do { if (--i < 0) goto err_full; bmap++; bm++; if (bmap < sbi->s_bmap_count) continue; /* restart search at zero */ bmap = 0; bm = sbi->s_bitmap; } while (!bm->bm_free); blk = bmap * sbi->s_bmap_bits;
find_bmap_bit:
bh = sbi->s_bmap_bh; if (sbi->s_last_bmap != bmap) { affs_brelse(bh); bh = affs_bread(sb, bm->bm_key); if (!bh) goto err_bh_read; sbi->s_bmap_bh = bh; sbi->s_last_bmap = bmap; }
/* find an unused block in this bitmap block */ bit = blk % sbi->s_bmap_bits; data = (__be32 *)bh->b_data + bit / 32 + 1; enddata = (__be32 *)((u8 *)bh->b_data + sb->s_blocksize); mask = ~0UL << (bit & 31); blk &= ~31UL;
tmp = be32_to_cpu(*data); if (tmp & mask) goto find_bit;
/* scan the rest of the buffer */ do { blk += 32; if (++data >= enddata) /* didn't find something, can only happen * if scan didn't start at 0, try next bmap */ goto find_bmap; } while (!*data); tmp = be32_to_cpu(*data); mask = ~0;
find_bit: /* finally look for a free bit in the word */ bit = ffs(tmp & mask) - 1; blk += bit + sbi->s_reserved; mask2 = mask = 1 << (bit & 31); AFFS_I(inode)->i_lastalloc = blk;
/* prealloc as much as possible within this word */ while ((mask2 <<= 1)) { if (!(tmp & mask2)) break; AFFS_I(inode)->i_pa_cnt++; mask |= mask2; } bm->bm_free -= AFFS_I(inode)->i_pa_cnt + 1;
*data = cpu_to_be32(tmp & ~mask);
/* fix checksum */ tmp = be32_to_cpu(*(__be32 *)bh->b_data); *(__be32 *)bh->b_data = cpu_to_be32(tmp + mask);
mark_buffer_dirty(bh); affs_mark_sb_dirty(sb);
mutex_unlock(&sbi->s_bmlock);
pr_debug("%d\n", blk); return blk;
err_bh_read: affs_error(sb,"affs_read_block","Cannot read bitmap block %u", bm->bm_key); sbi->s_bmap_bh = NULL; sbi->s_last_bmap = ~0;err_full: mutex_unlock(&sbi->s_bmlock); pr_debug("failed\n"); return 0;}
int affs_init_bitmap(struct super_block *sb, int *flags){ struct affs_bm_info *bm; struct buffer_head *bmap_bh = NULL, *bh = NULL; __be32 *bmap_blk; u32 size, blk, end, offset, mask; int i, res = 0; struct affs_sb_info *sbi = AFFS_SB(sb);
if (*flags & SB_RDONLY) return 0;
if (!AFFS_ROOT_TAIL(sb, sbi->s_root_bh)->bm_flag) { pr_notice("Bitmap invalid - mounting %s read only\n", sb->s_id); *flags |= SB_RDONLY; return 0; }
sbi->s_last_bmap = ~0; sbi->s_bmap_bh = NULL; sbi->s_bmap_bits = sb->s_blocksize * 8 - 32; sbi->s_bmap_count = (sbi->s_partition_size - sbi->s_reserved + sbi->s_bmap_bits - 1) / sbi->s_bmap_bits; size = sbi->s_bmap_count * sizeof(*bm); bm = sbi->s_bitmap = kzalloc(size, GFP_KERNEL); if (!sbi->s_bitmap) { pr_err("Bitmap allocation failed\n"); return -ENOMEM; }
bmap_blk = (__be32 *)sbi->s_root_bh->b_data; blk = sb->s_blocksize / 4 - 49; end = blk + 25;
for (i = sbi->s_bmap_count; i > 0; bm++, i--) { affs_brelse(bh);
bm->bm_key = be32_to_cpu(bmap_blk[blk]); bh = affs_bread(sb, bm->bm_key); if (!bh) { pr_err("Cannot read bitmap\n"); res = -EIO; goto out; } if (affs_checksum_block(sb, bh)) { pr_warn("Bitmap %u invalid - mounting %s read only.\n", bm->bm_key, sb->s_id); *flags |= SB_RDONLY; goto out; } pr_debug("read bitmap block %d: %d\n", blk, bm->bm_key); bm->bm_free = memweight(bh->b_data + 4, sb->s_blocksize - 4);
/* Don't try read the extension if this is the last block, * but we also need the right bm pointer below */ if (++blk < end || i == 1) continue; if (bmap_bh) affs_brelse(bmap_bh); bmap_bh = affs_bread(sb, be32_to_cpu(bmap_blk[blk])); if (!bmap_bh) { pr_err("Cannot read bitmap extension\n"); res = -EIO; goto out; } bmap_blk = (__be32 *)bmap_bh->b_data; blk = 0; end = sb->s_blocksize / 4 - 1; }
offset = (sbi->s_partition_size - sbi->s_reserved) % sbi->s_bmap_bits; mask = ~(0xFFFFFFFFU << (offset & 31)); pr_debug("last word: %d %d %d\n", offset, offset / 32 + 1, mask); offset = offset / 32 + 1;
if (mask) { u32 old, new;
/* Mark unused bits in the last word as allocated */ old = be32_to_cpu(((__be32 *)bh->b_data)[offset]); new = old & mask; //if (old != new) { ((__be32 *)bh->b_data)[offset] = cpu_to_be32(new); /* fix checksum */ //new -= old; //old = be32_to_cpu(*(__be32 *)bh->b_data); //*(__be32 *)bh->b_data = cpu_to_be32(old - new); //mark_buffer_dirty(bh); //} /* correct offset for the bitmap count below */ //offset++; } while (++offset < sb->s_blocksize / 4) ((__be32 *)bh->b_data)[offset] = 0; ((__be32 *)bh->b_data)[0] = 0; ((__be32 *)bh->b_data)[0] = cpu_to_be32(-affs_checksum_block(sb, bh)); mark_buffer_dirty(bh);
/* recalculate bitmap count for last block */ bm--; bm->bm_free = memweight(bh->b_data + 4, sb->s_blocksize - 4);
out: affs_brelse(bh); affs_brelse(bmap_bh); return res;}
void affs_free_bitmap(struct super_block *sb){ struct affs_sb_info *sbi = AFFS_SB(sb);
if (!sbi->s_bitmap) return;
affs_brelse(sbi->s_bmap_bh); sbi->s_bmap_bh = NULL; sbi->s_last_bmap = ~0; kfree(sbi->s_bitmap); sbi->s_bitmap = NULL;}