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/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-

 * vim:expandtab:shiftwidth=8:tabstop=8:

 *

 *  Copyright (C) 1998 Peter J. Braam <braam@clusterfs.com>

 *  Copyright (C) 2000 Red Hat, Inc.

 *  Copyright (C) 2000 Los Alamos National Laboratory

 *  Copyright (C) 2000 TurboLinux, Inc.

 *  Copyright (C) 2001 Mountain View Data, Inc.

 *  Copyright (C) 2001 Tacit Networks, Inc. <phil@off.net>

 *

 *   This file is part of InterMezzo, http://www.inter-mezzo.org.

 *

 *   InterMezzo is free software; you can redistribute it and/or

 *   modify it under the terms of version 2 of the GNU General Public

 *   License as published by the Free Software Foundation.

 *

 *   InterMezzo is distributed in the hope that it will be useful,

 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *   GNU General Public License for more details.

 *

 *   You should have received a copy of the GNU General Public License

 *   along with InterMezzo; if not, write to the Free Software

 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 */

#include <linux/types.h>

#include <linux/param.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/fs.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>

#include <linux/stat.h>

#include <linux/errno.h>

#include <linux/locks.h>

#include <asm/segment.h>

#include <asm/uaccess.h>

#include <linux/string.h>

#include <linux/smp_lock.h>

#if defined(CONFIG_EXT3_FS) || defined (CONFIG_EXT3_FS_MODULE)

#include <linux/jbd.h>

#include <linux/ext3_fs.h>

#include <linux/ext3_jbd.h>

#endif

#include <linux/intermezzo_fs.h>

#include <linux/intermezzo_psdev.h>

#if defined(CONFIG_EXT3_FS) || defined (CONFIG_EXT3_FS_MODULE)

#define MAX_PATH_BLOCKS(inode) (PATH_MAX >> EXT3_BLOCK_SIZE_BITS((inode)->i_sb))

#define MAX_NAME_BLOCKS(inode) (NAME_MAX >> EXT3_BLOCK_SIZE_BITS((inode)->i_sb))

/* space requirements:

   presto_do_truncate:

        used to truncate the KML forward to next fset->chunksize boundary

          - zero partial block

          - update inode

   presto_write_record:

        write header (< one block)

        write one path (< MAX_PATHLEN)

        possibly write another path (< MAX_PATHLEN)

        write suffix (< one block)

   presto_update_last_rcvd

        write one block

*/

static loff_t presto_e3_freespace(struct presto_cache *cache,

                                         struct super_block *sb)

{

        loff_t freebl = le32_to_cpu(sb->u.ext3_sb.s_es->s_free_blocks_count);

        loff_t avail =   freebl -

                le32_to_cpu(sb->u.ext3_sb.s_es->s_r_blocks_count);

        return (avail <<  EXT3_BLOCK_SIZE_BITS(sb));

}

/* start the filesystem journal operations */

static void *presto_e3_trans_start(struct presto_file_set *fset,

                                   struct inode *inode,

                                   int op)

{

        int jblocks;

        int trunc_blks, one_path_blks, extra_path_blks,

                extra_name_blks, lml_blks;

        __u32 avail_kmlblocks;

        handle_t *handle;

        if ( presto_no_journal(fset) ||

             strcmp(fset->fset_cache->cache_type, "ext3"))

          {

            CDEBUG(D_JOURNAL, "got cache_type \"%s\"\n",

                   fset->fset_cache->cache_type);

            return NULL;

          }

        avail_kmlblocks = inode->i_sb->u.ext3_sb.s_es->s_free_blocks_count;

        if ( avail_kmlblocks < 3 ) {

                return ERR_PTR(-ENOSPC);

        }

        if (  (op != KML_OPCODE_UNLINK && op != KML_OPCODE_RMDIR)

              && avail_kmlblocks < 6 ) {

                return ERR_PTR(-ENOSPC);

        }

        /* Need journal space for:

             at least three writes to KML (two one block writes, one a path)

             possibly a second name (unlink, rmdir)

             possibly a second path (symlink, rename)

             a one block write to the last rcvd file

        */

        trunc_blks = EXT3_DATA_TRANS_BLOCKS + 1;

        one_path_blks = 4*EXT3_DATA_TRANS_BLOCKS + MAX_PATH_BLOCKS(inode) + 3;

        lml_blks = 4*EXT3_DATA_TRANS_BLOCKS + MAX_PATH_BLOCKS(inode) + 2;

        extra_path_blks = EXT3_DATA_TRANS_BLOCKS + MAX_PATH_BLOCKS(inode);

        extra_name_blks = EXT3_DATA_TRANS_BLOCKS + MAX_NAME_BLOCKS(inode);

        /* additional blocks appear for "two pathname" operations

           and operations involving the LML records

        */

        switch (op) {

        case KML_OPCODE_TRUNC:

                jblocks = one_path_blks + extra_name_blks + trunc_blks

                        + EXT3_DELETE_TRANS_BLOCKS;

                break;

        case KML_OPCODE_KML_TRUNC:

                /* Hopefully this is a little better, but I'm still mostly

                 * guessing here. */

                /* unlink 1 */

                jblocks = extra_name_blks + trunc_blks +

                        EXT3_DELETE_TRANS_BLOCKS + 2;

                /* unlink 2 */

                jblocks += extra_name_blks + trunc_blks +

                        EXT3_DELETE_TRANS_BLOCKS + 2;

                /* rename 1 */

                jblocks += 2 * extra_path_blks + trunc_blks +

                        2 * EXT3_DATA_TRANS_BLOCKS + 2 + 3;

                /* rename 2 */

                jblocks += 2 * extra_path_blks + trunc_blks +

                        2 * EXT3_DATA_TRANS_BLOCKS + 2 + 3;

                break;

        case KML_OPCODE_RELEASE:

                /*

                jblocks = one_path_blks + lml_blks + 2*trunc_blks;

                */

                jblocks = one_path_blks;

                break;

        case KML_OPCODE_SETATTR:

                jblocks = one_path_blks + trunc_blks + 1 ;

                break;

        case KML_OPCODE_CREATE:

                jblocks = one_path_blks + trunc_blks

                        + EXT3_DATA_TRANS_BLOCKS + 3 + 2;

                break;

        case KML_OPCODE_LINK:

                jblocks = one_path_blks + trunc_blks

                        + EXT3_DATA_TRANS_BLOCKS + 2;

                break;

        case KML_OPCODE_UNLINK:

                jblocks = one_path_blks + extra_name_blks + trunc_blks

                        + EXT3_DELETE_TRANS_BLOCKS + 2;

                break;

        case KML_OPCODE_SYMLINK:

                jblocks = one_path_blks + extra_path_blks + trunc_blks

                        + EXT3_DATA_TRANS_BLOCKS + 5;

                break;

        case KML_OPCODE_MKDIR:

                jblocks = one_path_blks + trunc_blks

                        + EXT3_DATA_TRANS_BLOCKS + 4 + 2;

                break;

        case KML_OPCODE_RMDIR:

                jblocks = one_path_blks + extra_name_blks + trunc_blks

                        + EXT3_DELETE_TRANS_BLOCKS + 1;

                break;

        case KML_OPCODE_MKNOD:

                jblocks = one_path_blks + trunc_blks +

                        EXT3_DATA_TRANS_BLOCKS + 3 + 2;

                break;

        case KML_OPCODE_RENAME:

                jblocks = one_path_blks + extra_path_blks + trunc_blks +

                        2 * EXT3_DATA_TRANS_BLOCKS + 2 + 3;

                break;

        case KML_OPCODE_WRITE:

                jblocks = one_path_blks;

                /*  add this when we can wrap our transaction with

                    that of ext3_file_write (ordered writes)

                    +  EXT3_DATA_TRANS_BLOCKS;

                */

                break;

        default:

                CDEBUG(D_JOURNAL, "invalid operation %d for journal\n", op);

                return NULL;

        }

        CDEBUG(D_JOURNAL, "creating journal handle (%d blocks) for op %d\n",

               jblocks, op);

        /* journal_start/stop does not do its own locking while updating

         * the handle/transaction information. Hence we create our own

         * critical section to protect these calls. -SHP

         */

        lock_kernel();

        handle = journal_start(EXT3_JOURNAL(inode), jblocks);

        unlock_kernel();

        return handle;

}

static void presto_e3_trans_commit(struct presto_file_set *fset, void *handle)

{

        if ( presto_no_journal(fset) || !handle)

                return;

        /* See comments before journal_start above. -SHP */

        lock_kernel();

        journal_stop(handle);

        unlock_kernel();

}

static void presto_e3_journal_file_data(struct inode *inode)

{

#ifdef EXT3_JOURNAL_DATA_FL

        inode->u.ext3_i.i_flags |= EXT3_JOURNAL_DATA_FL;

#else

#warning You must have a facility to enable journaled writes for recovery!

#endif

}

/* The logic here is a slightly modified version of ext3/inode.c:block_to_path

 */

static int presto_e3_has_all_data(struct inode *inode)

{

        int ptrs = EXT3_ADDR_PER_BLOCK(inode->i_sb);

        int ptrs_bits = EXT3_ADDR_PER_BLOCK_BITS(inode->i_sb);

        const long direct_blocks = EXT3_NDIR_BLOCKS,

                indirect_blocks = ptrs,

                double_blocks = (1 << (ptrs_bits * 2));

        long block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>

                inode->i_sb->s_blocksize_bits;

        ENTRY;

        if (inode->i_size == 0) {

                EXIT;

                return 1;

        }

        if (block < direct_blocks) {

                /* No indirect blocks, no problem. */

        } else if (block < indirect_blocks + direct_blocks) {

                block++;

        } else if (block < double_blocks + indirect_blocks + direct_blocks) {

                block += 2;

        } else if (((block - double_blocks - indirect_blocks - direct_blocks)

                    >> (ptrs_bits * 2)) < ptrs) {

                block += 3;

        }

        block *= (inode->i_sb->s_blocksize / 512);

        CDEBUG(D_CACHE, "Need %ld blocks, have %ld.\n", block, inode->i_blocks);

        if (block > inode->i_blocks) {

                EXIT;

                return 0;

        }

        EXIT;

        return 1;

}

struct journal_ops presto_ext3_journal_ops = {

        .tr_all_data     = presto_e3_has_all_data,

        .tr_avail        = presto_e3_freespace,

        .tr_start        =  presto_e3_trans_start,

        .tr_commit       = presto_e3_trans_commit,

        .tr_journal_data = presto_e3_journal_file_data,

        .tr_ilookup      = presto_iget_ilookup

};

#endif /* CONFIG_EXT3_FS */