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/* -*- mode: c; c-basic-offset: 8; -*-

 * vim: noexpandtab sw=8 ts=8 sts=0:

 *

 * journal.h

 *

 * Defines journalling api and structures.

 *

 * Copyright (C) 2003, 2005 Oracle.  All rights reserved.

 *

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

 * modify it under the terms of the GNU General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This program 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 this program; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 021110-1307, USA.

 */

#ifndef OCFS2_JOURNAL_H

#define OCFS2_JOURNAL_H

#include <linux/fs.h>

#include <linux/jbd.h>

enum ocfs2_journal_state {

        OCFS2_JOURNAL_FREE = 0,

        OCFS2_JOURNAL_LOADED,

        OCFS2_JOURNAL_IN_SHUTDOWN,

};

struct ocfs2_super;

struct ocfs2_dinode;

struct ocfs2_journal {

        enum ocfs2_journal_state   j_state;    /* Journals current state   */

        journal_t                 *j_journal; /* The kernels journal type */

        struct inode              *j_inode;   /* Kernel inode pointing to

                                               * this journal             */

        struct ocfs2_super        *j_osb;     /* pointer to the super

                                               * block for the node

                                               * we're currently

                                               * running on -- not

                                               * necessarily the super

                                               * block from the node

                                               * which we usually run

                                               * from (recovery,

                                               * etc)                     */

        struct buffer_head        *j_bh;      /* Journal disk inode block */

        atomic_t                  j_num_trans; /* Number of transactions

                                                * currently in the system. */

        unsigned long             j_trans_id;

        struct rw_semaphore       j_trans_barrier;

        wait_queue_head_t         j_checkpointed;

        spinlock_t                j_lock;

        struct list_head          j_la_cleanups;

        struct work_struct        j_recovery_work;

};

extern spinlock_t trans_inc_lock;

/* wrap j_trans_id so we never have it equal to zero. */

static inline unsigned long ocfs2_inc_trans_id(struct ocfs2_journal *j)

{

        unsigned long old_id;

        spin_lock(&trans_inc_lock);

        old_id = j->j_trans_id++;

        if (unlikely(!j->j_trans_id))

                j->j_trans_id = 1;

        spin_unlock(&trans_inc_lock);

        return old_id;

}

static inline void ocfs2_set_inode_lock_trans(struct ocfs2_journal *journal,

                                              struct inode *inode)

{

        spin_lock(&trans_inc_lock);

        OCFS2_I(inode)->ip_last_trans = journal->j_trans_id;

        spin_unlock(&trans_inc_lock);

}

/* Used to figure out whether it's safe to drop a metadata lock on an

 * inode. Returns true if all the inodes changes have been

 * checkpointed to disk. You should be holding the spinlock on the

 * metadata lock while calling this to be sure that nobody can take

 * the lock and put it on another transaction. */

static inline int ocfs2_inode_fully_checkpointed(struct inode *inode)

{

        int ret;

        struct ocfs2_journal *journal = OCFS2_SB(inode->i_sb)->journal;

        spin_lock(&trans_inc_lock);

        ret = time_after(journal->j_trans_id, OCFS2_I(inode)->ip_last_trans);

        spin_unlock(&trans_inc_lock);

        return ret;

}

/* convenience function to check if an inode is still new (has never

 * hit disk) Will do you a favor and set created_trans = 0 when you've

 * been checkpointed.  returns '1' if the inode is still new. */

static inline int ocfs2_inode_is_new(struct inode *inode)

{

        int ret;

        /* System files are never "new" as they're written out by

         * mkfs. This helps us early during mount, before we have the

         * journal open and j_trans_id could be junk. */

        if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_SYSTEM_FILE)

                return 0;

        spin_lock(&trans_inc_lock);

        ret = !(time_after(OCFS2_SB(inode->i_sb)->journal->j_trans_id,

                           OCFS2_I(inode)->ip_created_trans));

        if (!ret)

                OCFS2_I(inode)->ip_created_trans = 0;

        spin_unlock(&trans_inc_lock);

        return ret;

}

static inline void ocfs2_inode_set_new(struct ocfs2_super *osb,

                                       struct inode *inode)

{

        spin_lock(&trans_inc_lock);

        OCFS2_I(inode)->ip_created_trans = osb->journal->j_trans_id;

        spin_unlock(&trans_inc_lock);

}

/* Exported only for the journal struct init code in super.c. Do not call. */

void ocfs2_complete_recovery(struct work_struct *work);

/*

 *  Journal Control:

 *  Initialize, Load, Shutdown, Wipe a journal.

 *

 *  ocfs2_journal_init     - Initialize journal structures in the OSB.

 *  ocfs2_journal_load     - Load the given journal off disk. Replay it if

 *                          there's transactions still in there.

 *  ocfs2_journal_shutdown - Shutdown a journal, this will flush all

 *                          uncommitted, uncheckpointed transactions.

 *  ocfs2_journal_wipe     - Wipe transactions from a journal. Optionally

 *                          zero out each block.

 *  ocfs2_recovery_thread  - Perform recovery on a node. osb is our own osb.

 *  ocfs2_mark_dead_nodes - Start recovery on nodes we won't get a heartbeat

 *                          event on.

 *  ocfs2_start_checkpoint - Kick the commit thread to do a checkpoint.

 */

void   ocfs2_set_journal_params(struct ocfs2_super *osb);

int    ocfs2_journal_init(struct ocfs2_journal *journal,

                          int *dirty);

void   ocfs2_journal_shutdown(struct ocfs2_super *osb);

int    ocfs2_journal_wipe(struct ocfs2_journal *journal,

                          int full);

int    ocfs2_journal_load(struct ocfs2_journal *journal, int local);

int    ocfs2_check_journals_nolocks(struct ocfs2_super *osb);

void   ocfs2_recovery_thread(struct ocfs2_super *osb,

                             int node_num);

int    ocfs2_mark_dead_nodes(struct ocfs2_super *osb);

void   ocfs2_complete_mount_recovery(struct ocfs2_super *osb);

static inline void ocfs2_start_checkpoint(struct ocfs2_super *osb)

{

        atomic_set(&osb->needs_checkpoint, 1);

        wake_up(&osb->checkpoint_event);

}

static inline void ocfs2_checkpoint_inode(struct inode *inode)

{

        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

        if (ocfs2_mount_local(osb))

                return;

        if (!ocfs2_inode_fully_checkpointed(inode)) {

                /* WARNING: This only kicks off a single

                 * checkpoint. If someone races you and adds more

                 * metadata to the journal, you won't know, and will

                 * wind up waiting *alot* longer than necessary. Right

                 * now we only use this in clear_inode so that's

                 * OK. */

                ocfs2_start_checkpoint(osb);

                wait_event(osb->journal->j_checkpointed,

                           ocfs2_inode_fully_checkpointed(inode));

        }

}

/*

 *  Transaction Handling:

 *  Manage the lifetime of a transaction handle.

 *

 *  ocfs2_start_trans      - Begin a transaction. Give it an upper estimate of

 *                          the number of blocks that will be changed during

 *                          this handle.

 *  ocfs2_commit_trans - Complete a handle. It might return -EIO if

 *                       the journal was aborted. The majority of paths don't

 *                       check the return value as an error there comes too

 *                       late to do anything (and will be picked up in a

 *                       later transaction).

 *  ocfs2_extend_trans     - Extend a handle by nblocks credits. This may

 *                          commit the handle to disk in the process, but will

 *                          not release any locks taken during the transaction.

 *  ocfs2_journal_access   - Notify the handle that we want to journal this

 *                          buffer. Will have to call ocfs2_journal_dirty once

 *                          we've actually dirtied it. Type is one of . or .

 *  ocfs2_journal_dirty    - Mark a journalled buffer as having dirty data.

 *  ocfs2_journal_dirty_data - Indicate that a data buffer should go out before

 *                             the current handle commits.

 */

/* You must always start_trans with a number of buffs > 0, but it's

 * perfectly legal to go through an entire transaction without having

 * dirtied any buffers. */

handle_t                    *ocfs2_start_trans(struct ocfs2_super *osb,

                                               int max_buffs);

int                          ocfs2_commit_trans(struct ocfs2_super *osb,

                                                handle_t *handle);

int                          ocfs2_extend_trans(handle_t *handle, int nblocks);

/*

 * Create access is for when we get a newly created buffer and we're

 * not gonna read it off disk, but rather fill it ourselves.  Right

 * now, we don't do anything special with this (it turns into a write

 * request), but this is a good placeholder in case we do...

 *

 * Write access is for when we read a block off disk and are going to

 * modify it. This way the journalling layer knows it may need to make

 * a copy of that block (if it's part of another, uncommitted

 * transaction) before we do so.

 */

#define OCFS2_JOURNAL_ACCESS_CREATE 0

#define OCFS2_JOURNAL_ACCESS_WRITE  1

#define OCFS2_JOURNAL_ACCESS_UNDO   2

int                  ocfs2_journal_access(handle_t *handle,

                                          struct inode *inode,

                                          struct buffer_head *bh,

                                          int type);

/*

 * A word about the journal_access/journal_dirty "dance". It is

 * entirely legal to journal_access a buffer more than once (as long

 * as the access type is the same -- I'm not sure what will happen if

 * access type is different but this should never happen anyway) It is

 * also legal to journal_dirty a buffer more than once. In fact, you

 * can even journal_access a buffer after you've done a

 * journal_access/journal_dirty pair. The only thing you cannot do

 * however, is journal_dirty a buffer which you haven't yet passed to

 * journal_access at least once.

 *

 * That said, 99% of the time this doesn't matter and this is what the

 * path looks like:

 *

 *      <read a bh>

 *      ocfs2_journal_access(handle, bh,        OCFS2_JOURNAL_ACCESS_WRITE);

 *      <modify the bh>

 *      ocfs2_journal_dirty(handle, bh);

 */

int                  ocfs2_journal_dirty(handle_t *handle,

                                         struct buffer_head *bh);

int                  ocfs2_journal_dirty_data(handle_t *handle,

                                              struct buffer_head *bh);

/*

 *  Credit Macros:

 *  Convenience macros to calculate number of credits needed.

 *

 *  For convenience sake, I have a set of macros here which calculate

 *  the *maximum* number of sectors which will be changed for various

 *  metadata updates.

 */

/* simple file updates like chmod, etc. */

#define OCFS2_INODE_UPDATE_CREDITS 1

/* get one bit out of a suballocator: dinode + group descriptor +

 * prev. group desc. if we relink. */

#define OCFS2_SUBALLOC_ALLOC (3)

#define OCFS2_INLINE_TO_EXTENTS_CREDITS (OCFS2_SUBALLOC_ALLOC           \

                                         + OCFS2_INODE_UPDATE_CREDITS)

/* dinode + group descriptor update. We don't relink on free yet. */

#define OCFS2_SUBALLOC_FREE  (2)

#define OCFS2_TRUNCATE_LOG_UPDATE OCFS2_INODE_UPDATE_CREDITS

#define OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC (OCFS2_SUBALLOC_FREE                 \

                                         + OCFS2_TRUNCATE_LOG_UPDATE)

#define OCFS2_REMOVE_EXTENT_CREDITS (OCFS2_TRUNCATE_LOG_UPDATE + OCFS2_INODE_UPDATE_CREDITS)

/* data block for new dir/symlink, 2 for bitmap updates (bitmap fe +

 * bitmap block for the new bit) */

#define OCFS2_DIR_LINK_ADDITIONAL_CREDITS (1 + 2)

/* parent fe, parent block, new file entry, inode alloc fe, inode alloc

 * group descriptor + mkdir/symlink blocks */

#define OCFS2_MKNOD_CREDITS (3 + OCFS2_SUBALLOC_ALLOC                         \

                            + OCFS2_DIR_LINK_ADDITIONAL_CREDITS)

/* local alloc metadata change + main bitmap updates */

#define OCFS2_WINDOW_MOVE_CREDITS (OCFS2_INODE_UPDATE_CREDITS                 \

                                  + OCFS2_SUBALLOC_ALLOC + OCFS2_SUBALLOC_FREE)

/* used when we don't need an allocation change for a dir extend. One

 * for the dinode, one for the new block. */

#define OCFS2_SIMPLE_DIR_EXTEND_CREDITS (2)

/* file update (nlink, etc) + directory mtime/ctime + dir entry block */

#define OCFS2_LINK_CREDITS  (2*OCFS2_INODE_UPDATE_CREDITS + 1)

/* inode + dir inode (if we unlink a dir), + dir entry block + orphan

 * dir inode link */

#define OCFS2_UNLINK_CREDITS  (2 * OCFS2_INODE_UPDATE_CREDITS + 1             \

                              + OCFS2_LINK_CREDITS)

/* dinode + orphan dir dinode + inode alloc dinode + orphan dir entry +

 * inode alloc group descriptor */

#define OCFS2_DELETE_INODE_CREDITS (3 * OCFS2_INODE_UPDATE_CREDITS + 1 + 1)

/* dinode update, old dir dinode update, new dir dinode update, old

 * dir dir entry, new dir dir entry, dir entry update for renaming

 * directory + target unlink */

#define OCFS2_RENAME_CREDITS (3 * OCFS2_INODE_UPDATE_CREDITS + 3              \

                             + OCFS2_UNLINK_CREDITS)

static inline int ocfs2_calc_extend_credits(struct super_block *sb,

                                            struct ocfs2_dinode *fe,

                                            u32 bits_wanted)

{

        int bitmap_blocks, sysfile_bitmap_blocks, dinode_blocks;

        /* bitmap dinode, group desc. + relinked group. */

        bitmap_blocks = OCFS2_SUBALLOC_ALLOC;

        /* we might need to shift tree depth so lets assume an

         * absolute worst case of complete fragmentation.  Even with

         * that, we only need one update for the dinode, and then

         * however many metadata chunks needed * a remaining suballoc

         * alloc. */

        sysfile_bitmap_blocks = 1 +

                (OCFS2_SUBALLOC_ALLOC - 1) * ocfs2_extend_meta_needed(fe);

        /* this does not include *new* metadata blocks, which are

         * accounted for in sysfile_bitmap_blocks. fe +

         * prev. last_eb_blk + blocks along edge of tree.

         * calc_symlink_credits passes because we just need 1

         * credit for the dinode there. */

        dinode_blocks = 1 + 1 + le16_to_cpu(fe->id2.i_list.l_tree_depth);

        return bitmap_blocks + sysfile_bitmap_blocks + dinode_blocks;

}

static inline int ocfs2_calc_symlink_credits(struct super_block *sb)

{

        int blocks = OCFS2_MKNOD_CREDITS;

        /* links can be longer than one block so we may update many

         * within our single allocated extent. */

        blocks += ocfs2_clusters_to_blocks(sb, 1);

        return blocks;

}

static inline int ocfs2_calc_group_alloc_credits(struct super_block *sb,

                                                 unsigned int cpg)

{

        int blocks;

        int bitmap_blocks = OCFS2_SUBALLOC_ALLOC + 1;

        /* parent inode update + new block group header + bitmap inode update

           + bitmap blocks affected */

        blocks = 1 + 1 + 1 + bitmap_blocks;

        return blocks;

}

static inline int ocfs2_calc_tree_trunc_credits(struct super_block *sb,

                                                unsigned int clusters_to_del,

                                                struct ocfs2_dinode *fe,

                                                struct ocfs2_extent_list *last_el)

{

        /* for dinode + all headers in this pass + update to next leaf */

        u16 next_free = le16_to_cpu(last_el->l_next_free_rec);

        u16 tree_depth = le16_to_cpu(fe->id2.i_list.l_tree_depth);

        int credits = 1 + tree_depth + 1;

        int i;

        i = next_free - 1;

        BUG_ON(i < 0);

        /* We may be deleting metadata blocks, so metadata alloc dinode +

           one desc. block for each possible delete. */

        if (tree_depth && next_free == 1 &&

            ocfs2_rec_clusters(last_el, &last_el->l_recs[i]) == clusters_to_del)

                credits += 1 + tree_depth;

        /* update to the truncate log. */

        credits += OCFS2_TRUNCATE_LOG_UPDATE;

        return credits;

}

#endif /* OCFS2_JOURNAL_H */