Re: [PATCH v8] f2fs: support dynamic reserve/release for device aliasing

From: Chao Yu

Date: Thu Aug 20 2026 - 19:59:00 EST


On 8/21/26 05:16, Daeho Jeong wrote:
From: Daeho Jeong <daehojeong@xxxxxxxxxx>

This patch adds a dynamic management feature to the existing device
aliasing functionality. It allows users to dynamically reserve or
release specific devices from the filesystem's free pool at runtime
through new ioctls.

To support this, three new ioctls are introduced:
- F2FS_IOC_RESERVE_DEV_ALIAS: This reclaims the space occupied by a
device aliasing file. It first performs a capacity check, resets GC
victim information for the target range, marks the segments as in-use
to prevent new allocations, and then triggers GC to migrate existing
valid data out of the range. Finally, it reserves these blocks in the
SIT to effectively exclude the device from the usable capacity.

- F2FS_IOC_RELEASE_DEV_ALIAS: This releases the reserved space of a
previously reserved device aliasing file. It truncates the blocks
associated with the file, which makes them available for general
filesystem allocation again.

- F2FS_IOC_GET_DEV_ALIAS_STATUS: This retrieves the current aliasing
status of a device aliasing file, returning whether the file is
released (inactive alias) or reserved (active alias, with blocks
fully allocated on the device).

Signed-off-by: Daeho Jeong <daehojeong@xxxxxxxxxx>
Reviewed-by: Chao Yu <chao@xxxxxxxxxx>
---
v8: fixed device aliasing checks in f2fs_rename and f2fs_unlink.

The fix looks good to me, let me skip to reply w/ RVB since the patch
has already had it.

Thanks,