/*
   * ext4_jbd2.h
   *
   * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
   *
   * Copyright 1998--1999 Red Hat corp --- All Rights Reserved
   *
   * This file is part of the Linux kernel and is made available under
   * the terms of the GNU General Public License, version 2, or at your
   * option, any later version, incorporated herein by reference.
   *
   * Ext4-specific journaling extensions.
   */
  
  #ifndef _EXT4_JBD2_H
  #define _EXT4_JBD2_H
  
  #include <linux/fs.h>
  #include <linux/jbd2.h>
  #include "ext4.h"
  
  #define EXT4_JOURNAL(inode)	(EXT4_SB((inode)->i_sb)->s_journal)
  
  /* Define the number of blocks we need to account to a transaction to
   * modify one block of data.
   *
   * We may have to touch one inode, one bitmap buffer, up to three
   * indirection blocks, the group and superblock summaries, and the data
   * block to complete the transaction.
   *
   * For extents-enabled fs we may have to allocate and modify up to
   * 5 levels of tree, data block (for each of these we need bitmap + group
   * summaries), root which is stored in the inode, sb
   */
  
  #define EXT4_SINGLEDATA_TRANS_BLOCKS(sb)				\
  	(EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)   \
  	 ? 20U : 8U)
  
  /* Extended attribute operations touch at most two data buffers,
   * two bitmap buffers, and two group summaries, in addition to the inode
   * and the superblock, which are already accounted for. */
  
  #define EXT4_XATTR_TRANS_BLOCKS		6U
  
  /* Define the minimum size for a transaction which modifies data.  This
   * needs to take into account the fact that we may end up modifying two
   * quota files too (one for the group, one for the user quota).  The
   * superblock only gets updated once, of course, so don't bother
   * counting that again for the quota updates. */
  
  #define EXT4_DATA_TRANS_BLOCKS(sb)	(EXT4_SINGLEDATA_TRANS_BLOCKS(sb) + \
  					 EXT4_XATTR_TRANS_BLOCKS - 2 + \
  					 EXT4_MAXQUOTAS_TRANS_BLOCKS(sb))
  
  /*
   * Define the number of metadata blocks we need to account to modify data.
   *
   * This include super block, inode block, quota blocks and xattr blocks
   */
  #define EXT4_META_TRANS_BLOCKS(sb)	(EXT4_XATTR_TRANS_BLOCKS + \
  					EXT4_MAXQUOTAS_TRANS_BLOCKS(sb))
  
  /* Define an arbitrary limit for the amount of data we will anticipate
   * writing to any given transaction.  For unbounded transactions such as
   * write(2) and truncate(2) we can write more than this, but we always
   * start off at the maximum transaction size and grow the transaction
   * optimistically as we go. */
  
  #define EXT4_MAX_TRANS_DATA		64U
  
  /* We break up a large truncate or write transaction once the handle's
   * buffer credits gets this low, we need either to extend the
   * transaction or to start a new one.  Reserve enough space here for
   * inode, bitmap, superblock, group and indirection updates for at least
   * one block, plus two quota updates.  Quota allocations are not
   * needed. */
  
  #define EXT4_RESERVE_TRANS_BLOCKS	12U
  
  #define EXT4_INDEX_EXTRA_TRANS_BLOCKS	8
  
  #ifdef CONFIG_QUOTA
  /* Amount of blocks needed for quota update - we know that the structure was
   * allocated so we need to update only data block */
  #define EXT4_QUOTA_TRANS_BLOCKS(sb) ((test_opt(sb, QUOTA) ||\
  		EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA)) ?\
  		1 : 0)
  /* Amount of blocks needed for quota insert/delete - we do some block writes
   * but inode, sb and group updates are done only once */
  #define EXT4_QUOTA_INIT_BLOCKS(sb) ((test_opt(sb, QUOTA) ||\
  		EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA)) ?\
  		(DQUOT_INIT_ALLOC*(EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)\
  		 +3+DQUOT_INIT_REWRITE) : 0)
  
  #define EXT4_QUOTA_DEL_BLOCKS(sb) ((test_opt(sb, QUOTA) ||\
  		EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_QUOTA)) ?\
  		(DQUOT_DEL_ALLOC*(EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)\
  		 +3+DQUOT_DEL_REWRITE) : 0)
  #else
  #define EXT4_QUOTA_TRANS_BLOCKS(sb) 0
  #define EXT4_QUOTA_INIT_BLOCKS(sb) 0
  #define EXT4_QUOTA_DEL_BLOCKS(sb) 0
  #endif
  #define EXT4_MAXQUOTAS_TRANS_BLOCKS(sb) (MAXQUOTAS*EXT4_QUOTA_TRANS_BLOCKS(sb))
  #define EXT4_MAXQUOTAS_INIT_BLOCKS(sb) (MAXQUOTAS*EXT4_QUOTA_INIT_BLOCKS(sb))
  #define EXT4_MAXQUOTAS_DEL_BLOCKS(sb) (MAXQUOTAS*EXT4_QUOTA_DEL_BLOCKS(sb))
  
  static inline int ext4_jbd2_credits_xattr(struct inode *inode)
  {
  	int credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
  
  	/*
  	 * In case of inline data, we may push out the data to a block,
  	 * so we need to reserve credits for this eventuality
  	 */
  	if (ext4_has_inline_data(inode))
  		credits += ext4_writepage_trans_blocks(inode) + 1;
  	return credits;
  }
  
  
  /*
   * Ext4 handle operation types -- for logging purposes
   */
  #define EXT4_HT_MISC             0
  #define EXT4_HT_INODE            1
  #define EXT4_HT_WRITE_PAGE       2
  #define EXT4_HT_MAP_BLOCKS       3
  #define EXT4_HT_DIR              4
  #define EXT4_HT_TRUNCATE         5
  #define EXT4_HT_QUOTA            6
  #define EXT4_HT_RESIZE           7
  #define EXT4_HT_MIGRATE          8
  #define EXT4_HT_MOVE_EXTENTS     9
  #define EXT4_HT_XATTR           10
  #define EXT4_HT_EXT_CONVERT     11
  #define EXT4_HT_MAX             12
  
  /**
   *   struct ext4_journal_cb_entry - Base structure for callback information.
   *
   *   This struct is a 'seed' structure for a using with your own callback
   *   structs. If you are using callbacks you must allocate one of these
   *   or another struct of your own definition which has this struct
   *   as it's first element and pass it to ext4_journal_callback_add().
   */
  struct ext4_journal_cb_entry {
  	/* list information for other callbacks attached to the same handle */
  	struct list_head jce_list;
  
  	/*  Function to call with this callback structure */
  	void (*jce_func)(struct super_block *sb,
  			 struct ext4_journal_cb_entry *jce, int error);
  
  	/* user data goes here */
  };
  
  /**
   * ext4_journal_callback_add: add a function to call after transaction commit
   * @handle: active journal transaction handle to register callback on
   * @func: callback function to call after the transaction has committed:
   *        @sb: superblock of current filesystem for transaction
   *        @jce: returned journal callback data
   *        @rc: journal state at commit (0 = transaction committed properly)
   * @jce: journal callback data (internal and function private data struct)
   *
   * The registered function will be called in the context of the journal thread
   * after the transaction for which the handle was created has completed.
   *
   * No locks are held when the callback function is called, so it is safe to
   * call blocking functions from within the callback, but the callback should
   * not block or run for too long, or the filesystem will be blocked waiting for
   * the next transaction to commit. No journaling functions can be used, or
   * there is a risk of deadlock.
   *
   * There is no guaranteed calling order of multiple registered callbacks on
   * the same transaction.
   */
  static inline void ext4_journal_callback_add(handle_t *handle,
  			void (*func)(struct super_block *sb,
  				     struct ext4_journal_cb_entry *jce,
  				     int rc),
  			struct ext4_journal_cb_entry *jce)
  {
  	struct ext4_sb_info *sbi =
  			EXT4_SB(handle->h_transaction->t_journal->j_private);
  
  	/* Add the jce to transaction's private list */
  	jce->jce_func = func;
  	spin_lock(&sbi->s_md_lock);
  	list_add_tail(&jce->jce_list, &handle->h_transaction->t_private_list);
  	spin_unlock(&sbi->s_md_lock);
  }
  
  /**
   * ext4_journal_callback_del: delete a registered callback
   * @handle: active journal transaction handle on which callback was registered
   * @jce: registered journal callback entry to unregister
   * Return true if object was successfully removed
   */
  static inline bool ext4_journal_callback_try_del(handle_t *handle,
  					     struct ext4_journal_cb_entry *jce)
  {
  	bool deleted;
  	struct ext4_sb_info *sbi =
  			EXT4_SB(handle->h_transaction->t_journal->j_private);
  
  	spin_lock(&sbi->s_md_lock);
  	deleted = !list_empty(&jce->jce_list);
  	list_del_init(&jce->jce_list);
  	spin_unlock(&sbi->s_md_lock);
  	return deleted;
  }
  
  int
  ext4_mark_iloc_dirty(handle_t *handle,
  		     struct inode *inode,
  		     struct ext4_iloc *iloc);
  
  /*
   * On success, We end up with an outstanding reference count against
   * iloc->bh.  This _must_ be cleaned up later.
   */
  
  int ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
  			struct ext4_iloc *iloc);
  
  int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode);
  
  /*
   * Wrapper functions with which ext4 calls into JBD.
   */
  void ext4_journal_abort_handle(const char *caller, unsigned int line,
  			       const char *err_fn,
  		struct buffer_head *bh, handle_t *handle, int err);
  
  int __ext4_journal_get_write_access(const char *where, unsigned int line,
  				    handle_t *handle, struct buffer_head *bh);
  
  int __ext4_forget(const char *where, unsigned int line, handle_t *handle,
  		  int is_metadata, struct inode *inode,
  		  struct buffer_head *bh, ext4_fsblk_t blocknr);
  
  int __ext4_journal_get_create_access(const char *where, unsigned int line,
  				handle_t *handle, struct buffer_head *bh);
  
  int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
  				 handle_t *handle, struct inode *inode,
  				 struct buffer_head *bh);
  
  int __ext4_handle_dirty_super(const char *where, unsigned int line,
  			      handle_t *handle, struct super_block *sb);
  
  #define ext4_journal_get_write_access(handle, bh) \
  	__ext4_journal_get_write_access(__func__, __LINE__, (handle), (bh))
  #define ext4_forget(handle, is_metadata, inode, bh, block_nr) \
  	__ext4_forget(__func__, __LINE__, (handle), (is_metadata), (inode), \
  		      (bh), (block_nr))
  #define ext4_journal_get_create_access(handle, bh) \
  	__ext4_journal_get_create_access(__func__, __LINE__, (handle), (bh))
  #define ext4_handle_dirty_metadata(handle, inode, bh) \
  	__ext4_handle_dirty_metadata(__func__, __LINE__, (handle), (inode), \
  				     (bh))
  #define ext4_handle_dirty_super(handle, sb) \
  	__ext4_handle_dirty_super(__func__, __LINE__, (handle), (sb))
  
  handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line,
  				  int type, int blocks, int rsv_blocks);
  int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle);
  
  #define EXT4_NOJOURNAL_MAX_REF_COUNT ((unsigned long) 4096)
  
  /* Note:  Do not use this for NULL handles.  This is only to determine if
   * a properly allocated handle is using a journal or not. */
  static inline int ext4_handle_valid(handle_t *handle)
  {
  	if ((unsigned long)handle < EXT4_NOJOURNAL_MAX_REF_COUNT)
  		return 0;
  	return 1;
  }
  
  static inline void ext4_handle_sync(handle_t *handle)
  {
  	if (ext4_handle_valid(handle))
  		handle->h_sync = 1;
  }
  
  static inline int ext4_handle_is_aborted(handle_t *handle)
  {
  	if (ext4_handle_valid(handle))
  		return is_handle_aborted(handle);
  	return 0;
  }
  
  static inline int ext4_handle_has_enough_credits(handle_t *handle, int needed)
  {
  	if (ext4_handle_valid(handle) && handle->h_buffer_credits < needed)
  		return 0;
  	return 1;
  }
  
  #define ext4_journal_start_sb(sb, type, nblocks)			\
  	__ext4_journal_start_sb((sb), __LINE__, (type), (nblocks), 0)
  
  #define ext4_journal_start(inode, type, nblocks)			\
  	__ext4_journal_start((inode), __LINE__, (type), (nblocks), 0)
  
  #define ext4_journal_start_with_reserve(inode, type, blocks, rsv_blocks) \
  	__ext4_journal_start((inode), __LINE__, (type), (blocks), (rsv_blocks))
  
  static inline handle_t *__ext4_journal_start(struct inode *inode,
  					     unsigned int line, int type,
  					     int blocks, int rsv_blocks)
  {
  	return __ext4_journal_start_sb(inode->i_sb, line, type, blocks,
  				       rsv_blocks);
  }
  
  #define ext4_journal_stop(handle) \
  	__ext4_journal_stop(__func__, __LINE__, (handle))
  
  #define ext4_journal_start_reserved(handle, type) \
  	__ext4_journal_start_reserved((handle), __LINE__, (type))
  
  handle_t *__ext4_journal_start_reserved(handle_t *handle, unsigned int line,
  					int type);
  
  static inline void ext4_journal_free_reserved(handle_t *handle)
  {
  	if (ext4_handle_valid(handle))
  		jbd2_journal_free_reserved(handle);
  }
  
  static inline handle_t *ext4_journal_current_handle(void)
  {
  	return journal_current_handle();
  }
  
  static inline int ext4_journal_extend(handle_t *handle, int nblocks)
  {
  	if (ext4_handle_valid(handle))
  		return jbd2_journal_extend(handle, nblocks);
  	return 0;
  }
  
  static inline int ext4_journal_restart(handle_t *handle, int nblocks)
  {
  	if (ext4_handle_valid(handle))
  		return jbd2_journal_restart(handle, nblocks);
  	return 0;
  }
  
  static inline int ext4_journal_blocks_per_page(struct inode *inode)
  {
  	if (EXT4_JOURNAL(inode) != NULL)
  		return jbd2_journal_blocks_per_page(inode);
  	return 0;
  }
  
  static inline int ext4_journal_force_commit(journal_t *journal)
  {
  	if (journal)
  		return jbd2_journal_force_commit(journal);
  	return 0;
  }
  
  static inline int ext4_jbd2_file_inode(handle_t *handle, struct inode *inode)
  {
  	if (ext4_handle_valid(handle))
  		return jbd2_journal_file_inode(handle, EXT4_I(inode)->jinode);
  	return 0;
  }
  
  static inline void ext4_update_inode_fsync_trans(handle_t *handle,
  						 struct inode *inode,
  						 int datasync)
  {
  	struct ext4_inode_info *ei = EXT4_I(inode);
  
  	if (ext4_handle_valid(handle)) {
  		ei->i_sync_tid = handle->h_transaction->t_tid;
  		if (datasync)
  			ei->i_datasync_tid = handle->h_transaction->t_tid;
  	}
  }
  
  /* super.c */
  int ext4_force_commit(struct super_block *sb);
  
  /*
   * Ext4 inode journal modes
   */
  #define EXT4_INODE_JOURNAL_DATA_MODE	0x01 /* journal data mode */
  #define EXT4_INODE_ORDERED_DATA_MODE	0x02 /* ordered data mode */
  #define EXT4_INODE_WRITEBACK_DATA_MODE	0x04 /* writeback data mode */
  
  static inline int ext4_inode_journal_mode(struct inode *inode)
  {
  	if (EXT4_JOURNAL(inode) == NULL)
  		return EXT4_INODE_WRITEBACK_DATA_MODE;	/* writeback */
  	/* We do not support data journalling with delayed allocation */
  	if (!S_ISREG(inode->i_mode) ||
  	    test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
  		return EXT4_INODE_JOURNAL_DATA_MODE;	/* journal data */
  	if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA) &&
  	    !test_opt(inode->i_sb, DELALLOC))
  		return EXT4_INODE_JOURNAL_DATA_MODE;	/* journal data */
  	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
  		return EXT4_INODE_ORDERED_DATA_MODE;	/* ordered */
  	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
  		return EXT4_INODE_WRITEBACK_DATA_MODE;	/* writeback */
  	else
  		BUG();
  }
  
  static inline int ext4_should_journal_data(struct inode *inode)
  {
  	return ext4_inode_journal_mode(inode) & EXT4_INODE_JOURNAL_DATA_MODE;
  }
  
  static inline int ext4_should_order_data(struct inode *inode)
  {
  	return ext4_inode_journal_mode(inode) & EXT4_INODE_ORDERED_DATA_MODE;
  }
  
  static inline int ext4_should_writeback_data(struct inode *inode)
  {
  	return ext4_inode_journal_mode(inode) & EXT4_INODE_WRITEBACK_DATA_MODE;
  }
  
  /*
   * This function controls whether or not we should try to go down the
   * dioread_nolock code paths, which makes it safe to avoid taking
   * i_mutex for direct I/O reads.  This only works for extent-based
   * files, and it doesn't work if data journaling is enabled, since the
   * dioread_nolock code uses b_private to pass information back to the
   * I/O completion handler, and this conflicts with the jbd's use of
   * b_private.
   */
  static inline int ext4_should_dioread_nolock(struct inode *inode)
  {
  	if (!test_opt(inode->i_sb, DIOREAD_NOLOCK))
  		return 0;
  	if (!S_ISREG(inode->i_mode))
  		return 0;
  	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
  		return 0;
  	if (ext4_should_journal_data(inode))
  		return 0;
  	return 1;
  }
  
  #endif	/* _EXT4_JBD2_H */