fs/ext4/ext4_jbd2.h - kernel/skids - Git at Google

 /*
  * 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 + root which are stored in the inode. */

 #define EXT4_SINGLEDATA_TRANS_BLOCKS(sb)				\
 	(EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)   \
 	 ? 27U : 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))

 /* Delete operations potentially hit one directory's namespace plus an
  * entire inode, plus arbitrary amounts of bitmap/indirection data.  Be
  * generous.  We can grow the delete transaction later if necessary. */

 #define EXT4_DELETE_TRANS_BLOCKS(sb)	(2 * EXT4_DATA_TRANS_BLOCKS(sb) + 64)

 /* 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 inode+data */
 #define EXT4_QUOTA_TRANS_BLOCKS(sb) (test_opt(sb, QUOTA) ? 2 : 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) ? (DQUOT_INIT_ALLOC*\
 		(EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)+3+DQUOT_INIT_REWRITE) : 0)

 #define EXT4_QUOTA_DEL_BLOCKS(sb) (test_opt(sb, 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))

 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, const char *err_fn,
 		struct buffer_head *bh, handle_t *handle, int err);

 int __ext4_journal_get_undo_access(const char *where, handle_t *handle,
 				struct buffer_head *bh);

 int __ext4_journal_get_write_access(const char *where, handle_t *handle,
 				struct buffer_head *bh);

 int __ext4_forget(const char *where, 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,
 				handle_t *handle, struct buffer_head *bh);

 int __ext4_handle_dirty_metadata(const char *where, handle_t *handle,
 				 struct inode *inode, struct buffer_head *bh);

 #define ext4_journal_get_undo_access(handle, bh) \
 	__ext4_journal_get_undo_access(__func__, (handle), (bh))
 #define ext4_journal_get_write_access(handle, bh) \
 	__ext4_journal_get_write_access(__func__, (handle), (bh))
 #define ext4_forget(handle, is_metadata, inode, bh, block_nr) \
 	__ext4_forget(__func__, (handle), (is_metadata), (inode), (bh),\
 		      (block_nr))
 #define ext4_journal_get_create_access(handle, bh) \
 	__ext4_journal_get_create_access(__func__, (handle), (bh))
 #define ext4_handle_dirty_metadata(handle, inode, bh) \
 	__ext4_handle_dirty_metadata(__func__, (handle), (inode), (bh))

 handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks);
 int __ext4_journal_stop(const char *where, 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 void ext4_handle_release_buffer(handle_t *handle,
 						struct buffer_head *bh)
 {
 	if (ext4_handle_valid(handle))
 		jbd2_journal_release_buffer(handle, bh);
 }

 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;
 }

 static inline void ext4_journal_release_buffer(handle_t *handle,
 						struct buffer_head *bh)
 {
 	if (ext4_handle_valid(handle))
 		jbd2_journal_release_buffer(handle, bh);
 }

 static inline handle_t *ext4_journal_start(struct inode *inode, int nblocks)
 {
 	return ext4_journal_start_sb(inode->i_sb, nblocks);
 }

 #define ext4_journal_stop(handle) \
 	__ext4_journal_stop(__func__, (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);

 static inline int ext4_should_journal_data(struct inode *inode)
 {
 	if (EXT4_JOURNAL(inode) == NULL)
 		return 0;
 	if (!S_ISREG(inode->i_mode))
 		return 1;
 	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
 		return 1;
 	if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
 		return 1;
 	return 0;
 }

 static inline int ext4_should_order_data(struct inode *inode)
 {
 	if (EXT4_JOURNAL(inode) == NULL)
 		return 0;
 	if (!S_ISREG(inode->i_mode))
 		return 0;
 	if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
 		return 0;
 	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
 		return 1;
 	return 0;
 }

 static inline int ext4_should_writeback_data(struct inode *inode)
 {
 	if (!S_ISREG(inode->i_mode))
 		return 0;
 	if (EXT4_JOURNAL(inode) == NULL)
 		return 1;
 	if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
 		return 0;
 	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
 		return 1;
 	return 0;
 }

 /*
  * 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 for nobh or 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 (test_opt(inode->i_sb, NOBH))
 		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 */
	/*
	* 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 + root which are stored in the inode. */

	#define EXT4_SINGLEDATA_TRANS_BLOCKS(sb) \
	(EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS) \
	? 27U : 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))

	/* Delete operations potentially hit one directory's namespace plus an
	* entire inode, plus arbitrary amounts of bitmap/indirection data. Be
	* generous. We can grow the delete transaction later if necessary. */

	#define EXT4_DELETE_TRANS_BLOCKS(sb) (2 * EXT4_DATA_TRANS_BLOCKS(sb) + 64)

	/* 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 inode+data */
	#define EXT4_QUOTA_TRANS_BLOCKS(sb) (test_opt(sb, QUOTA) ? 2 : 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) ? (DQUOT_INIT_ALLOC*\
	(EXT4_SINGLEDATA_TRANS_BLOCKS(sb)-3)+3+DQUOT_INIT_REWRITE) : 0)

	#define EXT4_QUOTA_DEL_BLOCKS(sb) (test_opt(sb, 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))

	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, const char err_fn,
	struct buffer_head bh, handle_t handle, int err);

	int __ext4_journal_get_undo_access(const char where, handle_t handle,
	struct buffer_head *bh);

	int __ext4_journal_get_write_access(const char where, handle_t handle,
	struct buffer_head *bh);

	int __ext4_forget(const char where, 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,
	handle_t handle, struct buffer_head bh);

	int __ext4_handle_dirty_metadata(const char where, handle_t handle,
	struct inode inode, struct buffer_head bh);

	#define ext4_journal_get_undo_access(handle, bh) \
	__ext4_journal_get_undo_access(__func__, (handle), (bh))
	#define ext4_journal_get_write_access(handle, bh) \
	__ext4_journal_get_write_access(__func__, (handle), (bh))
	#define ext4_forget(handle, is_metadata, inode, bh, block_nr) \
	__ext4_forget(__func__, (handle), (is_metadata), (inode), (bh),\
	(block_nr))
	#define ext4_journal_get_create_access(handle, bh) \
	__ext4_journal_get_create_access(__func__, (handle), (bh))
	#define ext4_handle_dirty_metadata(handle, inode, bh) \
	__ext4_handle_dirty_metadata(__func__, (handle), (inode), (bh))

	handle_t ext4_journal_start_sb(struct super_block sb, int nblocks);
	int __ext4_journal_stop(const char where, 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 void ext4_handle_release_buffer(handle_t *handle,
	struct buffer_head *bh)
	{
	if (ext4_handle_valid(handle))
	jbd2_journal_release_buffer(handle, bh);
	}

	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;
	}

	static inline void ext4_journal_release_buffer(handle_t *handle,
	struct buffer_head *bh)
	{
	if (ext4_handle_valid(handle))
	jbd2_journal_release_buffer(handle, bh);
	}

	static inline handle_t ext4_journal_start(struct inode inode, int nblocks)
	{
	return ext4_journal_start_sb(inode->i_sb, nblocks);
	}

	#define ext4_journal_stop(handle) \
	__ext4_journal_stop(__func__, (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);

	static inline int ext4_should_journal_data(struct inode *inode)
	{
	if (EXT4_JOURNAL(inode) == NULL)
	return 0;
	if (!S_ISREG(inode->i_mode))
	return 1;
	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
	return 1;
	if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
	return 1;
	return 0;
	}

	static inline int ext4_should_order_data(struct inode *inode)
	{
	if (EXT4_JOURNAL(inode) == NULL)
	return 0;
	if (!S_ISREG(inode->i_mode))
	return 0;
	if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
	return 0;
	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
	return 1;
	return 0;
	}

	static inline int ext4_should_writeback_data(struct inode *inode)
	{
	if (!S_ISREG(inode->i_mode))
	return 0;
	if (EXT4_JOURNAL(inode) == NULL)
	return 1;
	if (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA))
	return 0;
	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
	return 1;
	return 0;
	}

	/*
	* 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 for nobh or 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 (test_opt(inode->i_sb, NOBH))
	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 */