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/*

 *  linux/fs/ext2/inode.c

 *

 * Copyright (C) 1992, 1993, 1994, 1995

 * Remy Card (card@masi.ibp.fr)

 * Laboratoire MASI - Institut Blaise Pascal

 * Universite Pierre et Marie Curie (Paris VI)

 *

 *  from

 *

 *  linux/fs/minix/inode.c

 *

 *  Copyright (C) 1991, 1992  Linus Torvalds

 *

 *  Goal-directed block allocation by Stephen Tweedie (sct@dcs.ed.ac.uk), 1993

 *  Big-endian to little-endian byte-swapping/bitmaps by

 *        David S. Miller (davem@caip.rutgers.edu), 1995

 */

#include <asm/segment.h>

#include <asm/system.h>

#include <linux/errno.h>

#include <linux/fs.h>

#include <linux/ext2_fs.h>

#include <linux/sched.h>

#include <linux/stat.h>

#include <linux/string.h>

#include <linux/locks.h>

#include <linux/mm.h>

static int ext2_update_inode(struct inode * inode, int do_sync);

void ext2_put_inode (struct inode * inode)

{

        ext2_discard_prealloc (inode);

        if (inode->i_nlink || inode->i_ino == EXT2_ACL_IDX_INO ||

            inode->i_ino == EXT2_ACL_DATA_INO)

                return;

        inode->u.ext2_i.i_dtime = CURRENT_TIME;

        inode->i_dirt = 1;

        ext2_update_inode(inode, IS_SYNC(inode));

        inode->i_size = 0;

        if (inode->i_blocks)

                ext2_truncate (inode);

        ext2_free_inode (inode);

}

#define inode_bmap(inode, nr) ((inode)->u.ext2_i.i_data[(nr)])

static inline int block_bmap (struct buffer_head * bh, int nr)

{

        int tmp;

        if (!bh)

                return 0;

        tmp = swab32(((u32 *) bh->b_data)[nr]);

        brelse (bh);

        return tmp;

}

/*

 * ext2_discard_prealloc and ext2_alloc_block are atomic wrt. the

 * superblock in the same manner as are ext2_free_blocks and

 * ext2_new_block.  We just wait on the super rather than locking it

 * here, since ext2_new_block will do the necessary locking and we

 * can't block until then.

 */

void ext2_discard_prealloc (struct inode * inode)

{

#ifdef EXT2_PREALLOCATE

        unsigned short total;

        if (inode->u.ext2_i.i_prealloc_count) {

                total = inode->u.ext2_i.i_prealloc_count;

                inode->u.ext2_i.i_prealloc_count = 0;

                ext2_free_blocks (inode, inode->u.ext2_i.i_prealloc_block, total);

        }

#endif

}

static int ext2_alloc_block (struct inode * inode, unsigned long goal, int * err)

{

#ifdef EXT2FS_DEBUG

        static unsigned long alloc_hits = 0, alloc_attempts = 0;

#endif

        unsigned long result;

        struct buffer_head * bh;

        wait_on_super (inode->i_sb);

#ifdef EXT2_PREALLOCATE

        if (inode->u.ext2_i.i_prealloc_count &&

            (goal == inode->u.ext2_i.i_prealloc_block ||

             goal + 1 == inode->u.ext2_i.i_prealloc_block))

        {

                result = inode->u.ext2_i.i_prealloc_block++;

                inode->u.ext2_i.i_prealloc_count--;

                ext2_debug ("preallocation hit (%lu/%lu).\n",

                            ++alloc_hits, ++alloc_attempts);

                /* It doesn't matter if we block in getblk() since

                   we have already atomically allocated the block, and

                   are only clearing it now. */

                if (!(bh = getblk (inode->i_sb->s_dev, result,

                                   inode->i_sb->s_blocksize))) {

                        ext2_error (inode->i_sb, "ext2_alloc_block",

                                    "cannot get block %lu", result);

                        return 0;

                }

                memset(bh->b_data, 0, inode->i_sb->s_blocksize);

                mark_buffer_uptodate(bh, 1);

                mark_buffer_dirty(bh, 1);

                brelse (bh);

        } else {

                ext2_discard_prealloc (inode);

                ext2_debug ("preallocation miss (%lu/%lu).\n",

                            alloc_hits, ++alloc_attempts);

                if (S_ISREG(inode->i_mode))

                        result = ext2_new_block (inode, goal,

                                 &inode->u.ext2_i.i_prealloc_count,

                                 &inode->u.ext2_i.i_prealloc_block, err);

                else

                        result = ext2_new_block (inode, goal, 0, 0, err);

        }

#else

        result = ext2_new_block (inode, goal, 0, 0, err);

#endif

        return result;

}

int ext2_bmap (struct inode * inode, int block)

{

        int i;

        int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);

        int addr_per_block_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);

        if (block < 0) {

                ext2_warning (inode->i_sb, "ext2_bmap", "block < 0");

                return 0;

        }

        if (block >= EXT2_NDIR_BLOCKS + addr_per_block +

                (1 << (addr_per_block_bits * 2)) +

                ((1 << (addr_per_block_bits * 2)) << addr_per_block_bits)) {

                ext2_warning (inode->i_sb, "ext2_bmap", "block > big");

                return 0;

        }

        if (block < EXT2_NDIR_BLOCKS)

                return inode_bmap (inode, block);

        block -= EXT2_NDIR_BLOCKS;

        if (block < addr_per_block) {

                i = inode_bmap (inode, EXT2_IND_BLOCK);

                if (!i)

                        return 0;

                return block_bmap (bread (inode->i_dev, i,

                                          inode->i_sb->s_blocksize), block);

        }

        block -= addr_per_block;

        if (block < (1 << (addr_per_block_bits * 2))) {

                i = inode_bmap (inode, EXT2_DIND_BLOCK);

                if (!i)

                        return 0;

                i = block_bmap (bread (inode->i_dev, i,

                                       inode->i_sb->s_blocksize),

                                block >> addr_per_block_bits);

                if (!i)

                        return 0;

                return block_bmap (bread (inode->i_dev, i,

                                          inode->i_sb->s_blocksize),

                                   block & (addr_per_block - 1));

        }

        block -= (1 << (addr_per_block_bits * 2));

        i = inode_bmap (inode, EXT2_TIND_BLOCK);

        if (!i)

                return 0;

        i = block_bmap (bread (inode->i_dev, i, inode->i_sb->s_blocksize),

                        block >> (addr_per_block_bits * 2));

        if (!i)

                return 0;

        i = block_bmap (bread (inode->i_dev, i, inode->i_sb->s_blocksize),

                        (block >> addr_per_block_bits) & (addr_per_block - 1));

        if (!i)

                return 0;

        return block_bmap (bread (inode->i_dev, i, inode->i_sb->s_blocksize),

                           block & (addr_per_block - 1));

}

static struct buffer_head * inode_getblk (struct inode * inode, int nr,

                                          int create, int new_block, int * err)

{

        u32 * p;

        int tmp, goal = 0;

        struct buffer_head * result;

        int blocks = inode->i_sb->s_blocksize / 512;

        p = inode->u.ext2_i.i_data + nr;

repeat:

        tmp = *p;

        if (tmp) {

                result = getblk (inode->i_dev, tmp, inode->i_sb->s_blocksize);

                if (tmp == *p)

                        return result;

                brelse (result);

                goto repeat;

        }

        if (!create || new_block >=

            (current->rlim[RLIMIT_FSIZE].rlim_cur >>

             EXT2_BLOCK_SIZE_BITS(inode->i_sb))) {

                *err = -EFBIG;

                return NULL;

        }

        if (inode->u.ext2_i.i_next_alloc_block == new_block)

                goal = inode->u.ext2_i.i_next_alloc_goal;

        ext2_debug ("hint = %d,", goal);

        if (!goal) {

                for (tmp = nr - 1; tmp >= 0; tmp--) {

                        if (inode->u.ext2_i.i_data[tmp]) {

                                goal = inode->u.ext2_i.i_data[tmp];

                                break;

                        }

                }

                if (!goal)

                        goal = (inode->u.ext2_i.i_block_group *

                                EXT2_BLOCKS_PER_GROUP(inode->i_sb)) +

                               swab32(inode->i_sb->u.ext2_sb.s_es->s_first_data_block);

        }

        ext2_debug ("goal = %d.\n", goal);

        tmp = ext2_alloc_block (inode, goal, err);

        if (!tmp)

                return NULL;

        result = getblk (inode->i_dev, tmp, inode->i_sb->s_blocksize);

        if (*p) {

                ext2_free_blocks (inode, tmp, 1);

                brelse (result);

                goto repeat;

        }

        *p = tmp;

        inode->u.ext2_i.i_next_alloc_block = new_block;

        inode->u.ext2_i.i_next_alloc_goal = tmp;

        inode->i_ctime = CURRENT_TIME;

        inode->i_blocks += blocks;

        if (IS_SYNC(inode) || inode->u.ext2_i.i_osync)

                ext2_sync_inode (inode);

        else

                inode->i_dirt = 1;

        return result;

}

static struct buffer_head * block_getblk (struct inode * inode,

                                          struct buffer_head * bh, int nr,

                                          int create, int blocksize,

                                          int new_block, int * err)

{

        int tmp, goal = 0;

        u32 * p;

        struct buffer_head * result;

        int blocks = inode->i_sb->s_blocksize / 512;

        if (!bh)

                return NULL;

        if (!buffer_uptodate(bh)) {

                ll_rw_block (READ, 1, &bh);

                wait_on_buffer (bh);

                if (!buffer_uptodate(bh)) {

                        brelse (bh);

                        return NULL;

                }

        }

        p = (u32 *) bh->b_data + nr;

repeat:

        tmp = swab32(*p);

        if (tmp) {

                result = getblk (bh->b_dev, tmp, blocksize);

                if (tmp == swab32(*p)) {

                        brelse (bh);

                        return result;

                }

                brelse (result);

                goto repeat;

        }

        if (!create || new_block >=

            (current->rlim[RLIMIT_FSIZE].rlim_cur >>

             EXT2_BLOCK_SIZE_BITS(inode->i_sb))) {

                brelse (bh);

                *err = -EFBIG;

                return NULL;

        }

        if (inode->u.ext2_i.i_next_alloc_block == new_block)

                goal = inode->u.ext2_i.i_next_alloc_goal;

        if (!goal) {

                for (tmp = nr - 1; tmp >= 0; tmp--) {

                        if (swab32(((u32 *) bh->b_data)[tmp])) {

                                goal = swab32(((u32 *)bh->b_data)[tmp]);

                                break;

                        }

                }

                if (!goal)

                        goal = bh->b_blocknr;

        }

        tmp = ext2_alloc_block (inode, goal, err);

        if (!tmp) {

                brelse (bh);

                return NULL;

        }

        result = getblk (bh->b_dev, tmp, blocksize);

        if (swab32(*p)) {

                ext2_free_blocks (inode, tmp, 1);

                brelse (result);

                goto repeat;

        }

        *p = swab32(tmp);

        mark_buffer_dirty(bh, 1);

        if (IS_SYNC(inode) || inode->u.ext2_i.i_osync) {

                ll_rw_block (WRITE, 1, &bh);

                wait_on_buffer (bh);

        }

        inode->i_ctime = CURRENT_TIME;

        inode->i_blocks += blocks;

        inode->i_dirt = 1;

        inode->u.ext2_i.i_next_alloc_block = new_block;

        inode->u.ext2_i.i_next_alloc_goal = tmp;

        brelse (bh);

        return result;

}

struct buffer_head * ext2_getblk (struct inode * inode, long block,

                                  int create, int * err)

{

        struct buffer_head * bh;

        unsigned long b;

        unsigned long addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);

        int addr_per_block_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);

        *err = -EIO;

        if (block < 0) {

                ext2_warning (inode->i_sb, "ext2_getblk", "block < 0");

                return NULL;

        }

        if (block > EXT2_NDIR_BLOCKS + addr_per_block +

                (1 << (addr_per_block_bits * 2)) +

                ((1 << (addr_per_block_bits * 2)) << addr_per_block_bits)) {

                ext2_warning (inode->i_sb, "ext2_getblk", "block > big");

                return NULL;

        }

        /*

         * If this is a sequential block allocation, set the next_alloc_block

         * to this block now so that all the indblock and data block

         * allocations use the same goal zone

         */

        ext2_debug ("block %lu, next %lu, goal %lu.\n", block,

                    inode->u.ext2_i.i_next_alloc_block,

                    inode->u.ext2_i.i_next_alloc_goal);

        if (block == inode->u.ext2_i.i_next_alloc_block + 1) {

                inode->u.ext2_i.i_next_alloc_block++;

                inode->u.ext2_i.i_next_alloc_goal++;

        }

        *err = -ENOSPC;

        b = block;

        if (block < EXT2_NDIR_BLOCKS)

                return inode_getblk (inode, block, create, b, err);

        block -= EXT2_NDIR_BLOCKS;

        if (block < addr_per_block) {

                bh = inode_getblk (inode, EXT2_IND_BLOCK, create, b, err);

                return block_getblk (inode, bh, block, create,

                                     inode->i_sb->s_blocksize, b, err);

        }

        block -= addr_per_block;

        if (block < (1 << (addr_per_block_bits * 2))) {

                bh = inode_getblk (inode, EXT2_DIND_BLOCK, create, b, err);

                bh = block_getblk (inode, bh, block >> addr_per_block_bits,

                                   create, inode->i_sb->s_blocksize, b, err);

                return block_getblk (inode, bh, block & (addr_per_block - 1),

                                     create, inode->i_sb->s_blocksize, b, err);

        }

        block -= (1 << (addr_per_block_bits * 2));

        bh = inode_getblk (inode, EXT2_TIND_BLOCK, create, b, err);

        bh = block_getblk (inode, bh, block >> (addr_per_block_bits * 2),

                           create, inode->i_sb->s_blocksize, b, err);

        bh = block_getblk (inode, bh, (block >> addr_per_block_bits) & (addr_per_block - 1),

                           create, inode->i_sb->s_blocksize, b, err);

        return block_getblk (inode, bh, block & (addr_per_block - 1), create,

                             inode->i_sb->s_blocksize, b, err);

}

struct buffer_head * ext2_bread (struct inode * inode, int block,

                                 int create, int *err)

{

        struct buffer_head * bh;

        bh = ext2_getblk (inode, block, create, err);

        if (!bh || buffer_uptodate(bh))

                return bh;

        ll_rw_block (READ, 1, &bh);

        wait_on_buffer (bh);

        if (buffer_uptodate(bh))

                return bh;

        brelse (bh);

        *err = -EIO;

        return NULL;

}

void ext2_read_inode (struct inode * inode)

{

        struct buffer_head * bh;

        struct ext2_inode * raw_inode;

        unsigned long block_group;

        unsigned long group_desc;

        unsigned long desc;

        unsigned long block;

        unsigned long offset;

        struct ext2_group_desc * gdp;

        if ((inode->i_ino != EXT2_ROOT_INO && inode->i_ino != EXT2_ACL_IDX_INO &&

             inode->i_ino != EXT2_ACL_DATA_INO &&

             inode->i_ino < EXT2_FIRST_INO(inode->i_sb)) ||

            inode->i_ino > swab32(inode->i_sb->u.ext2_sb.s_es->s_inodes_count)) {

                ext2_error (inode->i_sb, "ext2_read_inode",

                            "bad inode number: %lu", inode->i_ino);

                return;

        }

        block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);

        if (block_group >= inode->i_sb->u.ext2_sb.s_groups_count)

                ext2_panic (inode->i_sb, "ext2_read_inode",

                            "group >= groups count");

        group_desc = block_group >> EXT2_DESC_PER_BLOCK_BITS(inode->i_sb);

        desc = block_group & (EXT2_DESC_PER_BLOCK(inode->i_sb) - 1);

        bh = inode->i_sb->u.ext2_sb.s_group_desc[group_desc];

        if (!bh) {

                ext2_error (inode->i_sb, "ext2_read_inode",

                            "Descriptor not loaded");

                goto bad_inode;

        }

        gdp = (struct ext2_group_desc *) bh->b_data;

        /*

         * Figure out the offset within the block group inode table

         */

        offset = ((inode->i_ino - 1) % EXT2_INODES_PER_GROUP(inode->i_sb)) *

                EXT2_INODE_SIZE(inode->i_sb);

        block = swab32(gdp[desc].bg_inode_table) +

                (offset >> EXT2_BLOCK_SIZE_BITS(inode->i_sb));

        if (!(bh = bread (inode->i_dev, block, inode->i_sb->s_blocksize))) {

                ext2_error (inode->i_sb, "ext2_read_inode",

                            "unable to read i-node block - "

                            "inode=%lu, block=%lu", inode->i_ino, block);

                goto bad_inode;

        }

        offset &= (EXT2_BLOCK_SIZE(inode->i_sb) - 1);

        raw_inode = (struct ext2_inode *) (bh->b_data + offset);

        inode->i_mode = swab16(raw_inode->i_mode);

        inode->i_uid = swab16(raw_inode->i_uid);

        inode->i_gid = swab16(raw_inode->i_gid);

        inode->i_nlink = swab16(raw_inode->i_links_count);

        inode->i_size = swab32(raw_inode->i_size);

        inode->i_atime = swab32(raw_inode->i_atime);

        inode->i_ctime = swab32(raw_inode->i_ctime);

        inode->i_mtime = swab32(raw_inode->i_mtime);

        inode->u.ext2_i.i_dtime = swab32(raw_inode->i_dtime);

        inode->i_blksize = PAGE_SIZE;   /* This is the optimal IO size (for stat), not the fs block size */

        inode->i_blocks = swab32(raw_inode->i_blocks);

        inode->i_version = ++event;

        inode->u.ext2_i.i_new_inode = 0;

        inode->u.ext2_i.i_flags = swab32(raw_inode->i_flags);

        inode->u.ext2_i.i_faddr = swab32(raw_inode->i_faddr);

        inode->u.ext2_i.i_frag_no = raw_inode->i_frag;

        inode->u.ext2_i.i_frag_size = raw_inode->i_fsize;

        inode->u.ext2_i.i_osync = 0;

        inode->u.ext2_i.i_file_acl = swab32(raw_inode->i_file_acl);

        inode->u.ext2_i.i_dir_acl = swab32(raw_inode->i_dir_acl);

        inode->u.ext2_i.i_version = swab32(raw_inode->i_version);

        inode->u.ext2_i.i_block_group = block_group;

        inode->u.ext2_i.i_next_alloc_block = 0;

        inode->u.ext2_i.i_next_alloc_goal = 0;

        if (inode->u.ext2_i.i_prealloc_count)

                ext2_error (inode->i_sb, "ext2_read_inode",

                            "New inode has non-zero prealloc count!");

        if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))

                inode->i_rdev = to_kdev_t(swab32(raw_inode->i_block[0]));

        else if (S_ISLNK(inode->i_mode) && !inode->i_blocks)

                for (block = 0; block < EXT2_N_BLOCKS; block++)

                        inode->u.ext2_i.i_data[block] = raw_inode->i_block[block];

        else for (block = 0; block < EXT2_N_BLOCKS; block++)

                inode->u.ext2_i.i_data[block] = swab32(raw_inode->i_block[block]);

        brelse (bh);

        inode->i_op = NULL;

        if (inode->i_ino == EXT2_ACL_IDX_INO ||

            inode->i_ino == EXT2_ACL_DATA_INO)

                /* Nothing to do */ ;

        else if (S_ISREG(inode->i_mode))

                inode->i_op = &ext2_file_inode_operations;

        else if (S_ISDIR(inode->i_mode))

                inode->i_op = &ext2_dir_inode_operations;

        else if (S_ISLNK(inode->i_mode))

                inode->i_op = &ext2_symlink_inode_operations;

        else if (S_ISCHR(inode->i_mode))

                inode->i_op = &chrdev_inode_operations;

        else if (S_ISBLK(inode->i_mode))

                inode->i_op = &blkdev_inode_operations;

        else if (S_ISFIFO(inode->i_mode))

                init_fifo(inode);

        if (inode->u.ext2_i.i_flags & EXT2_SYNC_FL)

                inode->i_flags |= MS_SYNCHRONOUS;

        if (inode->u.ext2_i.i_flags & EXT2_APPEND_FL)

                inode->i_flags |= S_APPEND;

        if (inode->u.ext2_i.i_flags & EXT2_IMMUTABLE_FL)

                inode->i_flags |= S_IMMUTABLE;

        if (inode->u.ext2_i.i_flags & EXT2_NOATIME_FL)

                inode->i_flags |= MS_NOATIME;

        return;

bad_inode:

        make_bad_inode(inode);

        return;

}

static int ext2_update_inode(struct inode * inode, int do_sync)

{

        struct buffer_head * bh;

        struct ext2_inode * raw_inode;

        unsigned long block_group;

        unsigned long group_desc;

        unsigned long desc;

        unsigned long block;

        unsigned long offset;

        int err = 0;

        struct ext2_group_desc * gdp;

        if ((inode->i_ino != EXT2_ROOT_INO &&

             inode->i_ino < EXT2_FIRST_INO(inode->i_sb)) ||

            inode->i_ino > swab32(inode->i_sb->u.ext2_sb.s_es->s_inodes_count)) {

                ext2_error (inode->i_sb, "ext2_write_inode",

                            "bad inode number: %lu", inode->i_ino);

                return 0;

        }

        block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);

        if (block_group >= inode->i_sb->u.ext2_sb.s_groups_count)

                ext2_panic (inode->i_sb, "ext2_write_inode",

                            "group >= groups count");

        group_desc = block_group >> EXT2_DESC_PER_BLOCK_BITS(inode->i_sb);

        desc = block_group & (EXT2_DESC_PER_BLOCK(inode->i_sb) - 1);

        bh = inode->i_sb->u.ext2_sb.s_group_desc[group_desc];

        if (!bh)

                ext2_panic (inode->i_sb, "ext2_write_inode",

                            "Descriptor not loaded");

        gdp = (struct ext2_group_desc *) bh->b_data;

        /*

         * Figure out the offset within the block group inode table

         */

        offset = ((inode->i_ino - 1) % EXT2_INODES_PER_GROUP(inode->i_sb)) *

                EXT2_INODE_SIZE(inode->i_sb);

        block = swab32(gdp[desc].bg_inode_table) +

                (offset >> EXT2_BLOCK_SIZE_BITS(inode->i_sb));

        if (!(bh = bread (inode->i_dev, block, inode->i_sb->s_blocksize))) {

                ext2_error (inode->i_sb, "ext2_write_inode",

                            "unable to read i-node block - "

                            "inode=%lu, block=%lu", inode->i_ino, block);

                /*

                 * Unfortunately we're in a lose-lose situation.  I think that

                 * keeping the inode in-core with the dirty bit set is

                 * the worse option, since that will soak up inodes until

                 * the end of the world.  Clearing the dirty bit is nasty if

                 * we haven't succeeded in writing out, but it's less nasty

                 * than the alternative. -- sct

                 */

                inode->i_dirt = 0;

                return -EIO;

        }

        offset &= EXT2_BLOCK_SIZE(inode->i_sb) - 1;

        raw_inode = (struct ext2_inode *) (bh->b_data + offset);

        raw_inode->i_mode = swab16(inode->i_mode);

        raw_inode->i_uid = swab16(inode->i_uid);

        raw_inode->i_gid = swab16(inode->i_gid);

        raw_inode->i_links_count = swab16(inode->i_nlink);

        raw_inode->i_size = swab32(inode->i_size);

        raw_inode->i_atime = swab32(inode->i_atime);

        raw_inode->i_ctime = swab32(inode->i_ctime);

        raw_inode->i_mtime = swab32(inode->i_mtime);