On Tue 02-01-24 20:38:58, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@xxxxxxxxxx>
>
> Add a new map flag EXT4_MAP_DELAYED to indicate the mapping range is a
> delayed allocated only (not unwritten) one, and making
> ext4_map_blocks() can distinguish it, no longer mixing it with holes.
>
> Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
One small comment below.
> ---
> fs/ext4/ext4.h | 4 +++-
> fs/ext4/extents.c | 5 +++--
> fs/ext4/inode.c | 2 ++
> 3 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index a5d784872303..55195909d32f 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -252,8 +252,10 @@ struct ext4_allocation_request {
> #define EXT4_MAP_MAPPED BIT(BH_Mapped)
> #define EXT4_MAP_UNWRITTEN BIT(BH_Unwritten)
> #define EXT4_MAP_BOUNDARY BIT(BH_Boundary)
> +#define EXT4_MAP_DELAYED BIT(BH_Delay)
> #define EXT4_MAP_FLAGS (EXT4_MAP_NEW | EXT4_MAP_MAPPED |\
> - EXT4_MAP_UNWRITTEN | EXT4_MAP_BOUNDARY)
> + EXT4_MAP_UNWRITTEN | EXT4_MAP_BOUNDARY |\
> + EXT4_MAP_DELAYED)
>
> struct ext4_map_blocks {
> ext4_fsblk_t m_pblk;
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 0892d0568013..fc69f13cf510 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -4073,9 +4073,10 @@ static void ext4_ext_determine_hole(struct inode *inode,
> } else if (in_range(map->m_lblk, es.es_lblk, es.es_len)) {
> /*
> * Straddle the beginning of the queried range, it's no
> - * longer a hole, adjust the length to the delayed extent's
> - * after map->m_lblk.
> + * longer a hole, mark it is a delalloc and adjust the
> + * length to the delayed extent's after map->m_lblk.
> */
> + map->m_flags |= EXT4_MAP_DELAYED;
I wouldn't set delalloc bit here. If there's delalloc extent containing
lblk now, it means the caller of ext4_map_blocks() is not holding i_rwsem
(otherwise we would have found already in ext4_map_blocks()) and thus
delalloc info is unreliable anyway. So I wouldn't bother. But it's worth a
comment here like:
/*
* There's delalloc extent containing lblk. It must have
* been added after ext4_map_blocks() checked the extent
* status tree so we are not holding i_rwsem and delalloc
* info is only stabilized by i_data_sem we are going to
* release soon. Don't modify the extent status tree and
* report extent as a hole.
*/
Honza
> len = es.es_lblk + es.es_len - map->m_lblk;
> goto out;
> } else {
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 1b5e6409f958..c141bf6d8db2 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -515,6 +515,8 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
> map->m_len = retval;
> } else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
> map->m_pblk = 0;
> + map->m_flags |= ext4_es_is_delayed(&es) ?
> + EXT4_MAP_DELAYED : 0;
> retval = es.es_len - (map->m_lblk - es.es_lblk);
> if (retval > map->m_len)
> retval = map->m_len;
> --
> 2.39.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
