Re: [RFC] ext4: Add support for ext4_map_blocks_atomic()

From: John Garry
Date: Wed Mar 13 2024 - 15:14:19 EST


On 08/03/2024 20:25, Ritesh Harjani (IBM) wrote:

Hi Ritesh,

Currently ext4 exposes [fsawu_min, fsawu_max] size as
[blocksize, clustersize] (given the hw block device constraints are
larger than FS atomic write units).

That means a user should be allowed to -
1. pwrite 0 4k /mnt/test/f1
2. pwrite 0 16k /mnt/test/f1


Previously you have mentioned 2 or 3 methods in which ext4 could support atomic writes. To avoid doubt, is this patch for the "Add intelligence in multi-block allocator of ext4 to provide aligned allocations (this option won't require any formatting)" method mentioned at https://lore.kernel.org/linux-fsdevel/8734tb0xx7.fsf@xxxxxxx/

and same as method 3 at https://lore.kernel.org/linux-fsdevel/cover.1709356594.git.ritesh.list@xxxxxxxxx/?

Thanks,
John