journal.h

/* -*- 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);
void ocfs2_wait_for_recovery(struct ocfs2_super *osb);

int ocfs2_recovery_init(struct ocfs2_super *osb);
void ocfs2_recovery_exit(struct ocfs2_super *osb);

/*
 *  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

/* group extend. inode update and last group update. */
#define OCFS2_GROUP_EXTEND_CREDITS	(OCFS2_INODE_UPDATE_CREDITS + 1)

/* group add. inode update and the new group update. */
#define OCFS2_GROUP_ADD_CREDITS	(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 */