Re: [PATCH v4 07/12] ext4: using nofail preallocation in ext4_es_insert_delayed_block()

Jan Kara
2023-05-03T14:31:41Z

On Mon 24-04-23 11:38:41, Baokun Li wrote:
> Similar to in ext4_es_remove_extent(), we use a no-fail preallocation
> to avoid inconsistencies, except that here we may have to preallocate
> two extent_status.
>
> Suggested-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Baokun Li <libaokun1@huawei.com>

Looks good to me. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> fs/ext4/extents_status.c | 33 ++++++++++++++++++++++-----------
> 1 file changed, 22 insertions(+), 11 deletions(-)
>
> diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
> index f4d50cd501fc..f892277155fa 100644
> --- a/fs/ext4/extents_status.c
> +++ b/fs/ext4/extents_status.c
> @@ -2013,7 +2013,10 @@ int ext4_es_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk,
> bool allocated)
> {
> struct extent_status newes;
> - int err = 0;
> + int err1 = 0;
> + int err2 = 0;
> + struct extent_status *es1 = NULL;
> + struct extent_status *es2 = NULL;
>
> if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
> return 0;
> @@ -2028,29 +2031,37 @@ int ext4_es_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk,
>
> ext4_es_insert_extent_check(inode, &newes);
>
> +retry:
> + if (err1 && !es1)
> + es1 = __es_alloc_extent(true);
> + if ((err1 || err2) && !es2)
> + es2 = __es_alloc_extent(true);
> write_lock(&EXT4_I(inode)->i_es_lock);
>
> - err = __es_remove_extent(inode, lblk, lblk, NULL, NULL);
> - if (err != 0)
> + err1 = __es_remove_extent(inode, lblk, lblk, NULL, es1);
> + if (err1 != 0)
> goto error;
> -retry:
> - err = __es_insert_extent(inode, &newes, NULL);
> - if (err == -ENOMEM && __es_shrink(EXT4_SB(inode->i_sb),
> - 128, EXT4_I(inode)))
> - goto retry;
> - if (err != 0)
> +
> + err2 = __es_insert_extent(inode, &newes, es2);
> + if (err2 != 0)
> goto error;
>
> if (allocated)
> __insert_pending(inode, lblk);
>
> + /* es is pre-allocated but not used, free it. */
> + if (es1 && !es1->es_len)
> + __es_free_extent(es1);
> + if (es2 && !es2->es_len)
> + __es_free_extent(es2);
> error:
> write_unlock(&EXT4_I(inode)->i_es_lock);
> + if (err1 || err2)
> + goto retry;
>
> ext4_es_print_tree(inode);
> ext4_print_pending_tree(inode);
> -
> - return err;
> + return 0;
> }
>
> /*
> --
> 2.31.1
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR