Re: [RFC v4 linux-next 14/19] jbd2: prevent direct access of bd_inode

[Jan Kara <jack@suse.cz>]

On Thu 22-02-24 20:45:50, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
> 
> Now that all filesystems stash the bdev file, it's ok to get mapping
> from the file.
> 
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/ext4/super.c      |  2 +-
>  fs/jbd2/journal.c    | 26 +++++++++++++++-----------
>  include/linux/jbd2.h | 18 ++++++++++++++----
>  3 files changed, 30 insertions(+), 16 deletions(-)
> 
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 55b3df71bf5e..4df1a5cfe0a5 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -5918,7 +5918,7 @@ static journal_t *ext4_open_dev_journal(struct super_block *sb,
>  	if (IS_ERR(bdev_file))
>  		return ERR_CAST(bdev_file);
>  
> -	journal = jbd2_journal_init_dev(file_bdev(bdev_file), sb->s_bdev, j_start,
> +	journal = jbd2_journal_init_dev(bdev_file, sb->s_bdev_file, j_start,
>  					j_len, sb->s_blocksize);
>  	if (IS_ERR(journal)) {
>  		ext4_msg(sb, KERN_ERR, "failed to create device journal");
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index b6c114c11b97..abd42a6ccd0e 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -1516,11 +1516,12 @@ static int journal_load_superblock(journal_t *journal)
>   * very few fields yet: that has to wait until we have created the
>   * journal structures from from scratch, or loaded them from disk. */
>  
> -static journal_t *journal_init_common(struct block_device *bdev,
> -			struct block_device *fs_dev,
> +static journal_t *journal_init_common(struct file *bdev_file,
> +			struct file *fs_dev_file,
>  			unsigned long long start, int len, int blocksize)
>  {
>  	static struct lock_class_key jbd2_trans_commit_key;
> +	struct block_device *bdev = file_bdev(bdev_file);
>  	journal_t *journal;
>  	int err;
>  	int n;
> @@ -1531,7 +1532,9 @@ static journal_t *journal_init_common(struct block_device *bdev,
>  
>  	journal->j_blocksize = blocksize;
>  	journal->j_dev = bdev;
> -	journal->j_fs_dev = fs_dev;
> +	journal->j_dev_file = bdev_file;
> +	journal->j_fs_dev = file_bdev(fs_dev_file);
> +	journal->j_fs_dev_file = fs_dev_file;
>  	journal->j_blk_offset = start;
>  	journal->j_total_len = len;
>  	jbd2_init_fs_dev_write_error(journal);
> @@ -1628,8 +1631,8 @@ static journal_t *journal_init_common(struct block_device *bdev,
>  
>  /**
>   *  journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
> - *  @bdev: Block device on which to create the journal
> - *  @fs_dev: Device which hold journalled filesystem for this journal.
> + *  @bdev_file: Opened block device on which to create the journal
> + *  @fs_dev_file: Opened device which hold journalled filesystem for this journal.
>   *  @start: Block nr Start of journal.
>   *  @len:  Length of the journal in blocks.
>   *  @blocksize: blocksize of journalling device
> @@ -1640,13 +1643,13 @@ static journal_t *journal_init_common(struct block_device *bdev,
>   *  range of blocks on an arbitrary block device.
>   *
>   */
> -journal_t *jbd2_journal_init_dev(struct block_device *bdev,
> -			struct block_device *fs_dev,
> +journal_t *jbd2_journal_init_dev(struct file *bdev_file,
> +			struct file *fs_dev_file,
>  			unsigned long long start, int len, int blocksize)
>  {
>  	journal_t *journal;
>  
> -	journal = journal_init_common(bdev, fs_dev, start, len, blocksize);
> +	journal = journal_init_common(bdev_file, fs_dev_file, start, len, blocksize);
>  	if (IS_ERR(journal))
>  		return ERR_CAST(journal);
>  
> @@ -1683,8 +1686,9 @@ journal_t *jbd2_journal_init_inode(struct inode *inode)
>  		  inode->i_sb->s_id, inode->i_ino, (long long) inode->i_size,
>  		  inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
>  
> -	journal = journal_init_common(inode->i_sb->s_bdev, inode->i_sb->s_bdev,
> -			blocknr, inode->i_size >> inode->i_sb->s_blocksize_bits,
> +	journal = journal_init_common(inode->i_sb->s_bdev_file,
> +			inode->i_sb->s_bdev_file, blocknr,
> +			inode->i_size >> inode->i_sb->s_blocksize_bits,
>  			inode->i_sb->s_blocksize);
>  	if (IS_ERR(journal))
>  		return ERR_CAST(journal);
> @@ -2009,7 +2013,7 @@ static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
>  		byte_count = (block_stop - block_start + 1) *
>  				journal->j_blocksize;
>  
> -		truncate_inode_pages_range(journal->j_dev->bd_inode->i_mapping,
> +		truncate_inode_pages_range(journal->j_dev_file->f_mapping,
>  				byte_start, byte_stop);
>  
>  		if (flags & JBD2_JOURNAL_FLUSH_DISCARD) {
> diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
> index 971f3e826e15..fc26730ae8ef 100644
> --- a/include/linux/jbd2.h
> +++ b/include/linux/jbd2.h
> @@ -968,6 +968,11 @@ struct journal_s
>  	 */
>  	struct block_device	*j_dev;
>  
> +	/**
> +	 * @j_dev_file: Opended device @j_dev.
> +	 */
> +	struct file		*j_dev_file;
> +
>  	/**
>  	 * @j_blocksize: Block size for the location where we store the journal.
>  	 */
> @@ -993,6 +998,11 @@ struct journal_s
>  	 */
>  	struct block_device	*j_fs_dev;
>  
> +	/**
> +	 * @j_fs_dev_file: Opened device @j_fs_dev.
> +	 */
> +	struct file		*j_fs_dev_file;
> +
>  	/**
>  	 * @j_fs_dev_wb_err:
>  	 *
> @@ -1533,8 +1543,8 @@ extern void	 jbd2_journal_unlock_updates (journal_t *);
>  
>  void jbd2_journal_wait_updates(journal_t *);
>  
> -extern journal_t * jbd2_journal_init_dev(struct block_device *bdev,
> -				struct block_device *fs_dev,
> +extern journal_t *jbd2_journal_init_dev(struct file *bdev_file,
> +				struct file *fs_dev_file,
>  				unsigned long long start, int len, int bsize);
>  extern journal_t * jbd2_journal_init_inode (struct inode *);
>  extern int	   jbd2_journal_update_format (journal_t *);
> @@ -1696,7 +1706,7 @@ static inline void jbd2_journal_abort_handle(handle_t *handle)
>  
>  static inline void jbd2_init_fs_dev_write_error(journal_t *journal)
>  {
> -	struct address_space *mapping = journal->j_fs_dev->bd_inode->i_mapping;
> +	struct address_space *mapping = journal->j_fs_dev_file->f_mapping;
>  
>  	/*
>  	 * Save the original wb_err value of client fs's bdev mapping which
> @@ -1707,7 +1717,7 @@ static inline void jbd2_init_fs_dev_write_error(journal_t *journal)
>  
>  static inline int jbd2_check_fs_dev_write_error(journal_t *journal)
>  {
> -	struct address_space *mapping = journal->j_fs_dev->bd_inode->i_mapping;
> +	struct address_space *mapping = journal->j_fs_dev_file->f_mapping;
>  
>  	return errseq_check(&mapping->wb_err,
>  			    READ_ONCE(journal->j_fs_dev_wb_err));
> -- 
> 2.39.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR