Dmitry Monakhov <dmonakhov@xxxxxxxxxx> writes:
> This patch solves write vs chown race condition.
>
> Signed-off-by: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
> ---
> fs/ext4/ext4.h | 6 +++++-
> fs/ext4/inode.c | 13 ++++---------
> 2 files changed, 9 insertions(+), 10 deletions(-)
Oops.. i've forgot to init EXT4_I(inode)->i_reserved_quota before usage.
This is strange, but this wasn't triggered by my simple test :(
Will send new version.
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 26d3cf8..992cecd 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -705,6 +705,10 @@ struct ext4_inode_info {
> struct list_head i_aio_dio_complete_list;
> /* current io_end structure for async DIO write*/
> ext4_io_end_t *cur_aio_dio;
> +#ifdef CONFIG_QUOTA
> + /* quota space reservation, managed internally by quota code */
> + qsize_t i_reserved_quota;
> +#endif
> };
>
> /*
> @@ -1427,7 +1431,7 @@ extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks);
> extern int ext4_block_truncate_page(handle_t *handle,
> struct address_space *mapping, loff_t from);
> extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
> -extern qsize_t ext4_get_reserved_space(struct inode *inode);
> +extern qsize_t* ext4_get_reserved_space(struct inode *inode);
> extern int flush_aio_dio_completed_IO(struct inode *inode);
> /* ioctl.c */
> extern long ext4_ioctl(struct file *, unsigned int, unsigned long);
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index f693768..d833e5a 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -1048,17 +1048,12 @@ out:
> return err;
> }
>
> -qsize_t ext4_get_reserved_space(struct inode *inode)
> +#ifdef CONFIG_QUOTA
> +qsize_t* ext4_get_reserved_space(struct inode *inode)
> {
> - unsigned long long total;
> -
> - spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
> - total = EXT4_I(inode)->i_reserved_data_blocks +
> - EXT4_I(inode)->i_reserved_meta_blocks;
> - spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
> -
> - return (total << inode->i_blkbits);
> + return &EXT4_I(inode)->i_reserved_quota;
> }
> +#endif
> /*
> * Calculate the number of metadata blocks need to reserve
> * to allocate @blocks for non extent file based file
--
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