On Tue 03-01-23 10:28:12, zhanchengbin wrote:
> If ENOMEM fails when the extent is splitting, we need to restore the length
> of the split extent.
> In the ext4_split_extent_at function, only in ext4_ext_create_new_leaf will
> it alloc memory and change the shape of the extent tree,even if an ENOMEM
> is returned at this time, the extent tree is still self-consistent, Just
> restore the split extent lens in the function ext4_split_extent_at.
>
> ext4_split_extent_at
> ext4_ext_insert_extent
> ext4_ext_create_new_leaf
> 1)ext4_ext_split
> ext4_find_extent
> 2)ext4_ext_grow_indepth
> ext4_find_extent
>
> Signed-off-by: zhanchengbin <zhanchengbin1@xxxxxxxxxx>
Yeah that should work. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> Another solution is to add the __GFP_NOFAIL flag when allocating memory.
>
> fs/ext4/extents.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 9de1c9d1a13d..3559ea6b0781 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3251,7 +3251,7 @@ static int ext4_split_extent_at(handle_t *handle,
> ext4_ext_mark_unwritten(ex2);
>
> err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
> - if (err != -ENOSPC && err != -EDQUOT)
> + if (err != -ENOSPC && err != -EDQUOT && err != -ENOMEM)
> goto out;
>
> if (EXT4_EXT_MAY_ZEROOUT & split_flag) {
> --
> 2.31.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
