Re: [PATCH] udf: Fix deadlock when converting file from in-ICB one tonormal one

[Namjae Jeon]

2011/12/10 Jan Kara <jack@xxxxxxx>:
> During BKL removal, conversion of files from in-ICB format to normal format got
> broken. We call ->writepage with i_data_sem held but udf_get_block() also
> acquires i_data_sem thus creating A-A deadlock.
>
> We fix the problem by dropping i_data_sem before calling ->writepage() which is
> safe since i_mutex still protects us against any changes in the file. Also fix
> pagelock - i_data_sem lock inversion in udf_expand_file_adinicb() by dropping
> i_data_sem before calling find_or_create_page().
>
> Reported-by: Matthias Matiak <netzpython@xxxxxxxxxx>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Namjae Jeon <linkinjeon@xxxxxxxxx>
> ---
> Âfs/udf/file.c Â| Â Â6 +++---
> Âfs/udf/inode.c | Â 20 +++++++++++++++++---
> Â2 files changed, 20 insertions(+), 6 deletions(-)
>
> ÂI plan to merge this fix through my tree soon.
>
> +/*
> + * Expand file stored in ICB to a normal one-block-file
> + *
> + * This function requires i_data_sem for writing and releases it.
> + * This function requires i_mutex held
> + */
> Âint udf_expand_file_adinicb(struct inode *inode)
> Â{
> Â Â Â Âstruct page *page;
> @@ -171,6 +177,11 @@ int udf_expand_file_adinicb(struct inode *inode)
> Â Â Â Â Â Â Â Âmark_inode_dirty(inode);
                  up_write(&iinfo->i_data_sem);
Hi Jan.
I do not know if that helps, Would it need here ?
Thanks.
> Â Â Â Â Â Â Â Âreturn 0;
> Â Â Â Â}
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