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/*

 * balloc.c

 *

 * PURPOSE

 *      Block allocation handling routines for the OSTA-UDF(tm) filesystem.

 *

 * CONTACTS

 *      E-mail regarding any portion of the Linux UDF file system should be

 *      directed to the development team mailing list (run by majordomo):

 *              linux_udf@hpesjro.fc.hp.com

 *

 * COPYRIGHT

 *      This file is distributed under the terms of the GNU General Public

 *      License (GPL). Copies of the GPL can be obtained from:

 *              ftp://prep.ai.mit.edu/pub/gnu/GPL

 *      Each contributing author retains all rights to their own work.

 *

 *  (C) 1999-2001 Ben Fennema

 *  (C) 1999 Stelias Computing Inc

 *

 * HISTORY

 *

 *  02/24/99 blf  Created.

 *

 */

#include "udfdecl.h"

#include <linux/locks.h>

#include <linux/quotaops.h>

#include <asm/bitops.h>

#include "udf_i.h"

#include "udf_sb.h"

#define udf_clear_bit(nr,addr) ext2_clear_bit(nr,addr)

#define udf_set_bit(nr,addr) ext2_set_bit(nr,addr)

#define udf_test_bit(nr, addr) ext2_test_bit(nr, addr)

#define udf_find_first_one_bit(addr, size) find_first_one_bit(addr, size)

#define udf_find_next_one_bit(addr, size, offset) find_next_one_bit(addr, size, offset)

#define leBPL_to_cpup(x) leNUM_to_cpup(BITS_PER_LONG, x)

#define leNUM_to_cpup(x,y) xleNUM_to_cpup(x,y)

#define xleNUM_to_cpup(x,y) (le ## x ## _to_cpup(y))

#define uintBPL_t uint(BITS_PER_LONG)

#define uint(x) xuint(x)

#define xuint(x) uint ## x ## _t

extern inline int find_next_one_bit (void * addr, int size, int offset)

{

        uintBPL_t * p = ((uintBPL_t *) addr) + (offset / BITS_PER_LONG);

        uintBPL_t result = offset & ~(BITS_PER_LONG-1);

        uintBPL_t tmp;

        if (offset >= size)

                return size;

        size -= result;

        offset &= (BITS_PER_LONG-1);

        if (offset)

        {

                tmp = leBPL_to_cpup(p++);

                tmp &= ~0UL << offset;

                if (size < BITS_PER_LONG)

                        goto found_first;

                if (tmp)

                        goto found_middle;

                size -= BITS_PER_LONG;

                result += BITS_PER_LONG;

        }

        while (size & ~(BITS_PER_LONG-1))

        {

                if ((tmp = leBPL_to_cpup(p++)))

                        goto found_middle;

                result += BITS_PER_LONG;

                size -= BITS_PER_LONG;

        }

        if (!size)

                return result;

        tmp = leBPL_to_cpup(p);

found_first:

        tmp &= ~0UL >> (BITS_PER_LONG-size);

found_middle:

        return result + ffz(~tmp);

}

#define find_first_one_bit(addr, size)\

        find_next_one_bit((addr), (size), 0)

static int read_block_bitmap(struct super_block * sb,

        struct udf_bitmap *bitmap, unsigned int block, unsigned long bitmap_nr)

{

        struct buffer_head *bh = NULL;

        int retval = 0;

        lb_addr loc;

        loc.logicalBlockNum = bitmap->s_extPosition;

        loc.partitionReferenceNum = UDF_SB_PARTITION(sb);

        bh = udf_tread(sb, udf_get_lb_pblock(sb, loc, block));

        if (!bh)

        {

                retval = -EIO;

        }

        bitmap->s_block_bitmap[bitmap_nr] = bh;

        return retval;

}

static int __load_block_bitmap(struct super_block * sb,

        struct udf_bitmap *bitmap, unsigned int block_group)

{

        int retval = 0;

        int nr_groups = bitmap->s_nr_groups;

        if (block_group >= nr_groups)

        {

                udf_debug("block_group (%d) > nr_groups (%d)\n", block_group, nr_groups);

        }

        if (bitmap->s_block_bitmap[block_group])

                return block_group;

        else

        {

                retval = read_block_bitmap(sb, bitmap, block_group, block_group);

                if (retval < 0)

                        return retval;

                return block_group;

        }

}

static inline int load_block_bitmap(struct super_block * sb,

        struct udf_bitmap *bitmap, unsigned int block_group)

{

        int slot;

        slot = __load_block_bitmap(sb, bitmap, block_group);

        if (slot < 0)

                return slot;

        if (!bitmap->s_block_bitmap[slot])

                return -EIO;

        return slot;

}

static void udf_bitmap_free_blocks(struct super_block * sb,

        struct inode * inode,

        struct udf_bitmap *bitmap, lb_addr bloc, uint32_t offset, uint32_t count)

{

        struct buffer_head * bh = NULL;

        unsigned long block;

        unsigned long block_group;

        unsigned long bit;

        unsigned long i;

        int bitmap_nr;

        unsigned long overflow;

        lock_super(sb);

        if (bloc.logicalBlockNum < 0 ||

                (bloc.logicalBlockNum + count) > UDF_SB_PARTLEN(sb, bloc.partitionReferenceNum))

        {

                udf_debug("%d < %d || %d + %d > %d\n",

                        bloc.logicalBlockNum, 0, bloc.logicalBlockNum, count,

                        UDF_SB_PARTLEN(sb, bloc.partitionReferenceNum));

                goto error_return;

        }

        block = bloc.logicalBlockNum + offset + (sizeof(struct spaceBitmapDesc) << 3);

do_more:

        overflow = 0;

        block_group = block >> (sb->s_blocksize_bits + 3);

        bit = block % (sb->s_blocksize << 3);

        /*

         * Check to see if we are freeing blocks across a group boundary.

         */

        if (bit + count > (sb->s_blocksize << 3))

        {

                overflow = bit + count - (sb->s_blocksize << 3);

                count -= overflow;

        }

        bitmap_nr = load_block_bitmap(sb, bitmap, block_group);

        if (bitmap_nr < 0)

                goto error_return;

        bh = bitmap->s_block_bitmap[bitmap_nr];

        for (i=0; i < count; i++)

        {

                if (udf_set_bit(bit + i, bh->b_data))

                {

                        udf_debug("bit %ld already set\n", bit + i);

                        udf_debug("byte=%2x\n", ((char *)bh->b_data)[(bit + i) >> 3]);

                }

                else

                {

                        if (inode)

                                DQUOT_FREE_BLOCK(inode, 1);

                        if (UDF_SB_LVIDBH(sb))

                        {

                                UDF_SB_LVID(sb)->freeSpaceTable[UDF_SB_PARTITION(sb)] =

                                        cpu_to_le32(le32_to_cpu(UDF_SB_LVID(sb)->freeSpaceTable[UDF_SB_PARTITION(sb)])+1);

                        }

                }

        }

        mark_buffer_dirty(bh);

        if (overflow)

        {

                block += count;

                count = overflow;

                goto do_more;

        }

error_return:

        sb->s_dirt = 1;

        if (UDF_SB_LVIDBH(sb))

                mark_buffer_dirty(UDF_SB_LVIDBH(sb));

        unlock_super(sb);

        return;

}

static int udf_bitmap_prealloc_blocks(struct super_block * sb,

        struct inode * inode,

        struct udf_bitmap *bitmap, uint16_t partition, uint32_t first_block,

        uint32_t block_count)

{

        int alloc_count = 0;

        int bit, block, block_group, group_start;

        int nr_groups, bitmap_nr;

        struct buffer_head *bh;

        lock_super(sb);

        if (first_block < 0 || first_block >= UDF_SB_PARTLEN(sb, partition))

                goto out;

        if (first_block + block_count > UDF_SB_PARTLEN(sb, partition))

                block_count = UDF_SB_PARTLEN(sb, partition) - first_block;

repeat:

        nr_groups = (UDF_SB_PARTLEN(sb, partition) +

                (sizeof(struct spaceBitmapDesc) << 3) + (sb->s_blocksize * 8) - 1) / (sb->s_blocksize * 8);

        block = first_block + (sizeof(struct spaceBitmapDesc) << 3);

        block_group = block >> (sb->s_blocksize_bits + 3);

        group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);

        bitmap_nr = load_block_bitmap(sb, bitmap, block_group);

        if (bitmap_nr < 0)

                goto out;

        bh = bitmap->s_block_bitmap[bitmap_nr];

        bit = block % (sb->s_blocksize << 3);

        while (bit < (sb->s_blocksize << 3) && block_count > 0)

        {

                if (!udf_test_bit(bit, bh->b_data))

                        goto out;

                else if (DQUOT_PREALLOC_BLOCK(inode, 1))

                        goto out;

                else if (!udf_clear_bit(bit, bh->b_data))

                {

                        udf_debug("bit already cleared for block %d\n", bit);

                        DQUOT_FREE_BLOCK(inode, 1);

                        goto out;

                }

                block_count --;

                alloc_count ++;

                bit ++;

                block ++;

        }

        mark_buffer_dirty(bh);

        if (block_count > 0)

                goto repeat;

out:

        if (UDF_SB_LVIDBH(sb))

        {

                UDF_SB_LVID(sb)->freeSpaceTable[partition] =

                        cpu_to_le32(le32_to_cpu(UDF_SB_LVID(sb)->freeSpaceTable[partition])-alloc_count);

                mark_buffer_dirty(UDF_SB_LVIDBH(sb));

        }

        sb->s_dirt = 1;

        unlock_super(sb);

        return alloc_count;

}

static int udf_bitmap_new_block(struct super_block * sb,

        struct inode * inode,

        struct udf_bitmap *bitmap, uint16_t partition, uint32_t goal, int *err)

{

        int newbit, bit=0, block, block_group, group_start;

        int end_goal, nr_groups, bitmap_nr, i;

        struct buffer_head *bh = NULL;

        char *ptr;

        int newblock = 0;

        *err = -ENOSPC;

        lock_super(sb);

repeat:

        if (goal < 0 || goal >= UDF_SB_PARTLEN(sb, partition))

                goal = 0;

        nr_groups = bitmap->s_nr_groups;

        block = goal + (sizeof(struct spaceBitmapDesc) << 3);

        block_group = block >> (sb->s_blocksize_bits + 3);

        group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);

        bitmap_nr = load_block_bitmap(sb, bitmap, block_group);

        if (bitmap_nr < 0)

                goto error_return;

        bh = bitmap->s_block_bitmap[bitmap_nr];

        ptr = memscan((char *)bh->b_data + group_start, 0xFF, sb->s_blocksize - group_start);

        if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize)

        {

                bit = block % (sb->s_blocksize << 3);

                if (udf_test_bit(bit, bh->b_data))

                {

                        goto got_block;

                }

                end_goal = (bit + 63) & ~63;

                bit = udf_find_next_one_bit(bh->b_data, end_goal, bit);

                if (bit < end_goal)

                        goto got_block;

                ptr = memscan((char *)bh->b_data + (bit >> 3), 0xFF, sb->s_blocksize - ((bit + 7) >> 3));

                newbit = (ptr - ((char *)bh->b_data)) << 3;

                if (newbit < sb->s_blocksize << 3)

                {

                        bit = newbit;

                        goto search_back;

                }

                newbit = udf_find_next_one_bit(bh->b_data, sb->s_blocksize << 3, bit);

                if (newbit < sb->s_blocksize << 3)

                {

                        bit = newbit;

                        goto got_block;

                }

        }

        for (i=0; i<(nr_groups*2); i++)

        {

                block_group ++;

                if (block_group >= nr_groups)

                        block_group = 0;

                group_start = block_group ? 0 : sizeof(struct spaceBitmapDesc);

                bitmap_nr = load_block_bitmap(sb, bitmap, block_group);

                if (bitmap_nr < 0)

                        goto error_return;

                bh = bitmap->s_block_bitmap[bitmap_nr];

                if (i < nr_groups)

                {

                        ptr = memscan((char *)bh->b_data + group_start, 0xFF, sb->s_blocksize - group_start);

                        if ((ptr - ((char *)bh->b_data)) < sb->s_blocksize)

                        {

                                bit = (ptr - ((char *)bh->b_data)) << 3;

                                break;

                        }

                }

                else

                {

                        bit = udf_find_next_one_bit((char *)bh->b_data, sb->s_blocksize << 3, group_start << 3);

                        if (bit < sb->s_blocksize << 3)

                                break;

                }

        }

        if (i >= (nr_groups*2))

        {

                unlock_super(sb);

                return newblock;

        }

        if (bit < sb->s_blocksize << 3)

                goto search_back;

        else

                bit = udf_find_next_one_bit(bh->b_data, sb->s_blocksize << 3, group_start << 3);

        if (bit >= sb->s_blocksize << 3)

        {

                unlock_super(sb);

                return 0;

        }

search_back:

        for (i=0; i<7 && bit > (group_start << 3) && udf_test_bit(bit - 1, bh->b_data); i++, bit--);

got_block:

        /*

         * Check quota for allocation of this block.

         */

        if (inode && DQUOT_ALLOC_BLOCK(inode, 1))

        {

                unlock_super(sb);

                *err = -EDQUOT;

                return 0;

        }

        newblock = bit + (block_group << (sb->s_blocksize_bits + 3)) -

                (sizeof(struct spaceBitmapDesc) << 3);

        if (!udf_clear_bit(bit, bh->b_data))

        {

                udf_debug("bit already cleared for block %d\n", bit);

                goto repeat;

        }

        mark_buffer_dirty(bh);

        if (UDF_SB_LVIDBH(sb))

        {

                UDF_SB_LVID(sb)->freeSpaceTable[partition] =

                        cpu_to_le32(le32_to_cpu(UDF_SB_LVID(sb)->freeSpaceTable[partition])-1);

                mark_buffer_dirty(UDF_SB_LVIDBH(sb));

        }

        sb->s_dirt = 1;

        unlock_super(sb);

        *err = 0;

        return newblock;

error_return:

        *err = -EIO;

        unlock_super(sb);

        return 0;

}

static void udf_table_free_blocks(struct super_block * sb,

        struct inode * inode,

        struct inode * table, lb_addr bloc, uint32_t offset, uint32_t count)

{

        uint32_t start, end;

        uint32_t nextoffset, oextoffset, elen;

        lb_addr nbloc, obloc, eloc;

        struct buffer_head *obh, *nbh;

        int8_t etype;

        int i;

        lock_super(sb);

        if (bloc.logicalBlockNum < 0 ||

                (bloc.logicalBlockNum + count) > UDF_SB_PARTLEN(sb, bloc.partitionReferenceNum))

        {

                udf_debug("%d < %d || %d + %d > %d\n",

                        bloc.logicalBlockNum, 0, bloc.logicalBlockNum, count,

                        UDF_SB_PARTLEN(sb, bloc.partitionReferenceNum));

                goto error_return;

        }

        /* We do this up front - There are some error conditions that could occure,

           but.. oh well */

        if (inode)

                DQUOT_FREE_BLOCK(inode, count);

        if (UDF_SB_LVIDBH(sb))

        {

                UDF_SB_LVID(sb)->freeSpaceTable[UDF_SB_PARTITION(sb)] =

                        cpu_to_le32(le32_to_cpu(UDF_SB_LVID(sb)->freeSpaceTable[UDF_SB_PARTITION(sb)])+count);

                mark_buffer_dirty(UDF_SB_LVIDBH(sb));

        }

        start = bloc.logicalBlockNum + offset;

        end = bloc.logicalBlockNum + offset + count - 1;

        oextoffset = nextoffset = sizeof(struct unallocSpaceEntry);

        elen = 0;

        obloc = nbloc = UDF_I_LOCATION(table);

        obh = nbh = udf_tread(sb, udf_get_lb_pblock(sb, nbloc, 0));

        atomic_inc(&nbh->b_count);

        while (count && (etype =

                udf_next_aext(table, &nbloc, &nextoffset, &eloc, &elen, &nbh, 1)) != -1)

        {

                if (((eloc.logicalBlockNum + (elen >> sb->s_blocksize_bits)) ==

                        start))

                {

                        if ((0x3FFFFFFF - elen) < (count << sb->s_blocksize_bits))

                        {

                                count -= ((0x3FFFFFFF - elen) >> sb->s_blocksize_bits);

                                start += ((0x3FFFFFFF - elen) >> sb->s_blocksize_bits);

                                elen = (etype << 30) | (0x40000000 - sb->s_blocksize);

                        }

                        else

                        {

                                elen = (etype << 30) |

                                        (elen + (count << sb->s_blocksize_bits));

                                start += count;

                                count = 0;

                        }

                        udf_write_aext(table, obloc, &oextoffset, eloc, elen, obh, 1);

                }

                else if (eloc.logicalBlockNum == (end + 1))

                {

                        if ((0x3FFFFFFF - elen) < (count << sb->s_blocksize_bits))

                        {

                                count -= ((0x3FFFFFFF - elen) >> sb->s_blocksize_bits);

                                end -= ((0x3FFFFFFF - elen) >> sb->s_blocksize_bits);

                                eloc.logicalBlockNum -=

                                        ((0x3FFFFFFF - elen) >> sb->s_blocksize_bits);

                                elen = (etype << 30) | (0x40000000 - sb->s_blocksize);

                        }

                        else

                        {

                                eloc.logicalBlockNum = start;

                                elen = (etype << 30) |

                                        (elen + (count << sb->s_blocksize_bits));

                                end -= count;

                                count = 0;

                        }

                        udf_write_aext(table, obloc, &oextoffset, eloc, elen, obh, 1);

                }

                if (memcmp(&nbloc, &obloc, sizeof(lb_addr)))

                {

                        i = -1;

                        obloc = nbloc;

                        udf_release_data(obh);

                        atomic_inc(&nbh->b_count);

                        obh = nbh;

                        oextoffset = 0;

                }

                else

                        oextoffset = nextoffset;

        }

        if (count)

        {

                /* NOTE: we CANNOT use udf_add_aext here, as it can try to allocate

                                 a new block, and since we hold the super block lock already

                                 very bad things would happen :)

                                 We copy the behavior of udf_add_aext, but instead of

                                 trying to allocate a new block close to the existing one,

                                 we just steal a block from the extent we are trying to add.

                                 It would be nice if the blocks were close together, but it

                                 isn't required.

                */

                int adsize;

                short_ad *sad = NULL;

                long_ad *lad = NULL;

                struct allocExtDesc *aed;

                eloc.logicalBlockNum = start;

                elen = EXT_RECORDED_ALLOCATED |

                        (count << sb->s_blocksize_bits);

                if (UDF_I_ALLOCTYPE(table) == ICBTAG_FLAG_AD_SHORT)

                        adsize = sizeof(short_ad);

                else if (UDF_I_ALLOCTYPE(table) == ICBTAG_FLAG_AD_LONG)

                        adsize = sizeof(long_ad);

                else

                {

                        udf_release_data(obh);

                        udf_release_data(nbh);

                        goto error_return;

                }

                if (nextoffset + (2 * adsize) > sb->s_blocksize)

                {

                        char *sptr, *dptr;

                        int loffset;

                        udf_release_data(obh);

                        obh = nbh;

                        obloc = nbloc;

                        oextoffset = nextoffset;

                        /* Steal a block from the extent being free'd */

                        nbloc.logicalBlockNum = eloc.logicalBlockNum;

                        eloc.logicalBlockNum ++;

                        elen -= sb->s_blocksize;

                        if (!(nbh = udf_tread(sb,

                                udf_get_lb_pblock(sb, nbloc, 0))))

                        {

                                udf_release_data(obh);

                                goto error_return;

                        }

                        aed = (struct allocExtDesc *)(nbh->b_data);

                        aed->previousAllocExtLocation = cpu_to_le32(obloc.logicalBlockNum);

                        if (nextoffset + adsize > sb->s_blocksize)

                        {

                                loffset = nextoffset;

                                aed->lengthAllocDescs = cpu_to_le32(adsize);

                                sptr = (obh)->b_data + nextoffset - adsize;

                                dptr = nbh->b_data + sizeof(struct allocExtDesc);

                                memcpy(dptr, sptr, adsize);

                                nextoffset = sizeof(struct allocExtDesc) + adsize;

                        }

                        else

                        {

                                loffset = nextoffset + adsize;

                                aed->lengthAllocDescs = cpu_to_le32(0);

                                sptr = (obh)->b_data + nextoffset;

                                nextoffset = sizeof(struct allocExtDesc);

                                if (memcmp(&UDF_I_LOCATION(table), &obloc, sizeof(lb_addr)))

                                {

                                        aed = (struct allocExtDesc *)(obh)->b_data;

                                        aed->lengthAllocDescs =

                                                cpu_to_le32(le32_to_cpu(aed->lengthAllocDescs) + adsize);

                                }

                                else

                                {

                                        UDF_I_LENALLOC(table) += adsize;

                                        mark_inode_dirty(table);

                                }

                        }

                        if (UDF_SB_UDFREV(sb) >= 0x0200)

                                udf_new_tag(nbh->b_data, TAG_IDENT_AED, 3, 1,

                                        nbloc.logicalBlockNum, sizeof(tag));

                        else

                                udf_new_tag(nbh->b_data, TAG_IDENT_AED, 2, 1,

                                        nbloc.logicalBlockNum, sizeof(tag));

                        switch (UDF_I_ALLOCTYPE(table))

                        {

                                case ICBTAG_FLAG_AD_SHORT:

                                {

                                        sad = (short_ad *)sptr;

                                        sad->extLength = cpu_to_le32(

                                                EXT_NEXT_EXTENT_ALLOCDECS |

                                                sb->s_blocksize);

                                        sad->extPosition = cpu_to_le32(nbloc.logicalBlockNum);

                                        break;

                                }

                                case ICBTAG_FLAG_AD_LONG:

                                {

                                        lad = (long_ad *)sptr;

                                        lad->extLength = cpu_to_le32(

                                                EXT_NEXT_EXTENT_ALLOCDECS |