On Wed, Sep 25, 2024 at 07:19:26PM +0200, Jan Kara wrote:
> When meta_bg feature is enabled, the total number of group descriptors
> is not really limiting the filesystem size. So there's no reason to
> check it in that case. This allows resize2fs to resize filesystems past
> 256TB boundary similarly as the kernel can do it.
>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
Hi Jan,
Right this makes sense, I tested this using a sparse device:
# create a 1PB sparse device
sudo dmsetup create $SPARSE_DEVICE --table "0 $SIZE_1PB zero"
sudo dmsetup create $SNAPSHOT_NAME --table "0 $SIZE_1PB snapshot /dev/mapper/$SPARSE_DEVICE $BASE_DEVICE P 8"
sudo mkfs.ext4 /dev/mapper/$SNAPSHOT_NAME 512T
sudo resize2fs /dev/mapper/$SNAPSHOT_NAME 513T
This fails originally and works correctly with this patch applied. Infact without
this patch we end up failing 512T -> 512T resize as well which should just be
a no-op.
Feel free to add:
Reviewed-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
> ---
> resize/main.c | 29 ++++++++++++++++-------------
> 1 file changed, 16 insertions(+), 13 deletions(-)
>
> diff --git a/resize/main.c b/resize/main.c
> index f914c0507e97..08a4bbaf7c65 100644
> --- a/resize/main.c
> +++ b/resize/main.c
> @@ -270,8 +270,6 @@ int main (int argc, char ** argv)
> long sysval;
> int len, mount_flags;
> char *mtpt, *undo_file = NULL;
> - dgrp_t new_group_desc_count;
> - unsigned long new_desc_blocks;
>
> #ifdef ENABLE_NLS
> setlocale(LC_MESSAGES, "");
> @@ -551,17 +549,22 @@ int main (int argc, char ** argv)
> new_size &= ~((blk64_t)(1ULL << fs->cluster_ratio_bits) - 1);
> }
>
> - new_group_desc_count = ext2fs_div64_ceil(new_size -
> - fs->super->s_first_data_block,
> - EXT2_BLOCKS_PER_GROUP(fs->super));
> - new_desc_blocks = ext2fs_div_ceil(new_group_desc_count,
> - EXT2_DESC_PER_BLOCK(fs->super));
> - if ((new_desc_blocks + fs->super->s_first_data_block) >
> - EXT2_BLOCKS_PER_GROUP(fs->super)) {
> - com_err(program_name, 0,
> - _("New size results in too many block group "
> - "descriptors.\n"));
> - goto errout;
> + if (!ext2fs_has_feature_meta_bg(fs->super)) {
> + dgrp_t new_group_desc_count;
> + unsigned long new_desc_blocks;
> +
> + new_group_desc_count = ext2fs_div64_ceil(new_size -
> + fs->super->s_first_data_block,
> + EXT2_BLOCKS_PER_GROUP(fs->super));
> + new_desc_blocks = ext2fs_div_ceil(new_group_desc_count,
> + EXT2_DESC_PER_BLOCK(fs->super));
> + if ((new_desc_blocks + fs->super->s_first_data_block) >
> + EXT2_BLOCKS_PER_GROUP(fs->super)) {
> + com_err(program_name, 0,
> + _("New size results in too many block group "
> + "descriptors.\n"));
> + goto errout;
> + }
> }
>
> if (!force && new_size < min_size) {
> --
> 2.35.3
>
