Commit 8aefcd55 authored by Theodore Ts'o's avatar Theodore Ts'o
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ext4: dynamically allocate the jbd2_inode in ext4_inode_info as necessary 



Replace the jbd2_inode structure (which is 48 bytes) with a pointer
and only allocate the jbd2_inode when it is needed --- that is, when
the file system has a journal present and the inode has been opened
for writing.  This allows us to further slim down the ext4_inode_info
structure.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 353eb83c

fs/ext4/ext4.h

+1 −1
Original line number Diff line number Diff line
@@ -811,7 +811,7 @@ struct ext4_inode_info { 
	 */

	struct rw_semaphore i_data_sem;

	struct inode vfs_inode;

	struct jbd2_inode jinode;

	struct jbd2_inode *jinode;



	struct ext4_ext_cache i_cached_extent;

	/*

fs/ext4/ext4_jbd2.h

+1 −1
Original line number Diff line number Diff line
@@ -253,7 +253,7 @@ static inline int ext4_journal_force_commit(journal_t *journal) 
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 jbd2_journal_file_inode(handle, EXT4_I(inode)->jinode);

	return 0;

}

fs/ext4/file.c

+22 −0
Original line number Diff line number Diff line
@@ -104,6 +104,7 @@ static int ext4_file_open(struct inode * inode, struct file * filp) 
{

	struct super_block *sb = inode->i_sb;

	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);

	struct ext4_inode_info *ei = EXT4_I(inode);

	struct vfsmount *mnt = filp->f_path.mnt;

	struct path path;

	char buf[64], *cp;
@@ -127,6 +128,27 @@ static int ext4_file_open(struct inode * inode, struct file * filp) 
			ext4_mark_super_dirty(sb);

		}

	}

	/*

	 * Set up the jbd2_inode if we are opening the inode for

	 * writing and the journal is present

	 */

	if (sbi->s_journal && !ei->jinode && (filp->f_mode & FMODE_WRITE)) {

		struct jbd2_inode *jinode = jbd2_alloc_inode(GFP_KERNEL);



		spin_lock(&inode->i_lock);

		if (!ei->jinode) {

			if (!jinode) {

				spin_unlock(&inode->i_lock);

				return -ENOMEM;

			}

			ei->jinode = jinode;

			jbd2_journal_init_jbd_inode(ei->jinode, inode);

			jinode = NULL;

		}

		spin_unlock(&inode->i_lock);

		if (unlikely(jinode != NULL))

			jbd2_free_inode(jinode);

	}

	return dquot_file_open(inode, filp);

}

fs/ext4/inode.c

+12 −5
Original line number Diff line number Diff line
@@ -55,9 +55,16 @@ static inline int ext4_begin_ordered_truncate(struct inode *inode, 
					      loff_t new_size)

{

	trace_ext4_begin_ordered_truncate(inode, new_size);

	return jbd2_journal_begin_ordered_truncate(

					EXT4_SB(inode->i_sb)->s_journal,

					&EXT4_I(inode)->jinode,

	/*

	 * If jinode is zero, then we never opened the file for

	 * writing, so there's no need to call

	 * jbd2_journal_begin_ordered_truncate() since there's no

	 * outstanding writes we need to flush.

	 */

	if (!EXT4_I(inode)->jinode)

		return 0;

	return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),

						   EXT4_I(inode)->jinode,

						   new_size);

}
@@ -4054,7 +4061,7 @@ int ext4_block_truncate_page(handle_t *handle, 
	if (ext4_should_journal_data(inode)) {

		err = ext4_handle_dirty_metadata(handle, inode, bh);

	} else {

		if (ext4_should_order_data(inode))

		if (ext4_should_order_data(inode) && EXT4_I(inode)->jinode)

			err = ext4_jbd2_file_inode(handle, inode);

		mark_buffer_dirty(bh);

	}

fs/ext4/super.c

+7 −9
Original line number Diff line number Diff line
@@ -818,12 +818,6 @@ static struct inode *ext4_alloc_inode(struct super_block *sb) 
	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));

	INIT_LIST_HEAD(&ei->i_prealloc_list);

	spin_lock_init(&ei->i_prealloc_lock);

	/*

	 * Note:  We can be called before EXT4_SB(sb)->s_journal is set,

	 * therefore it can be null here.  Don't check it, just initialize

	 * jinode.

	 */

	jbd2_journal_init_jbd_inode(&ei->jinode, &ei->vfs_inode);

	ei->i_reserved_data_blocks = 0;

	ei->i_reserved_meta_blocks = 0;

	ei->i_allocated_meta_blocks = 0;
@@ -832,6 +826,7 @@ static struct inode *ext4_alloc_inode(struct super_block *sb) 
#ifdef CONFIG_QUOTA

	ei->i_reserved_quota = 0;

#endif

	ei->jinode = NULL;

	INIT_LIST_HEAD(&ei->i_completed_io_list);

	spin_lock_init(&ei->i_completed_io_lock);

	ei->cur_aio_dio = NULL;
@@ -900,9 +895,12 @@ void ext4_clear_inode(struct inode *inode) 
	end_writeback(inode);

	dquot_drop(inode);

	ext4_discard_preallocations(inode);

	if (EXT4_JOURNAL(inode))

		jbd2_journal_release_jbd_inode(EXT4_SB(inode->i_sb)->s_journal,

				       &EXT4_I(inode)->jinode);

	if (EXT4_I(inode)->jinode) {

		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),

					       EXT4_I(inode)->jinode);

		jbd2_free_inode(EXT4_I(inode)->jinode);

		EXT4_I(inode)->jinode = NULL;

	}

}



static inline void ext4_show_quota_options(struct seq_file *seq,

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