On Thu 03-10-19 21:34:51, Matthew Bobrowski wrote:
> For iomap direct IO write code path changes, we need to accommodate
> for the case where the block mapping flags passed to ext4_map_blocks()
> will result in m_flags having both EXT4_MAP_MAPPED and
> EXT4_MAP_UNWRITTEN bits set. In order for the allocated unwritten
> extents to be converted properly in the end_io handler, iomap->type
> must be set to IOMAP_UNWRITTEN, so we need to reshuffle the
> conditional statement in order to achieve this.
>
> This change is a no-op for DAX code path as the block mapping flag
> passed to ext4_map_blocks() when IS_DAX(inode) never results in
> EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN being set at once.
>
> Signed-off-by: Matthew Bobrowski <mbobrowski@xxxxxxxxxxxxxx>
The patch looks good to me. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Just those 72 columns limited comment lines... ;)
Honza
> ---
> fs/ext4/inode.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index e133dda55063..63ad23ae05b8 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3420,10 +3420,20 @@ static int ext4_set_iomap(struct inode *inode, struct iomap *iomap, u16 type,
> iomap->type = type;
> iomap->addr = IOMAP_NULL_ADDR;
> } else {
> - if (map->m_flags & EXT4_MAP_MAPPED) {
> - iomap->type = IOMAP_MAPPED;
> - } else if (map->m_flags & EXT4_MAP_UNWRITTEN) {
> + /*
> + * Flags passed to ext4_map_blocks() for direct I/O
> + * writes can result in map->m_flags having both
> + * EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits set. In
> + * order for allocated extents to be converted to
> + * written extents in the ->end_io handler correctly,
> + * we need to ensure that the iomap->type is set
> + * approprately. Thus, we need to check whether
> + * EXT4_MAP_UNWRITTEN is set first.
> + */
> + if (map->m_flags & EXT4_MAP_UNWRITTEN) {
> iomap->type = IOMAP_UNWRITTEN;
> + } else if (map->m_flags & EXT4_MAP_MAPPED) {
> + iomap->type = IOMAP_MAPPED;
> } else {
> WARN_ON_ONCE(1);
> return -EIO;
> --
> 2.20.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
