Re: [PATCH] ext4: don't free the tmp_inode tree after a partial migration swap

[sashiko-bot@kernel.org]

> ext4_ext_migrate() cleans up the temporary inode when
> ext4_ext_swap_inode_data() fails:
> 
> 	retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode);
> 	if (retval)
> 		free_ext_block(handle, tmp_inode);
> 
> ext4_ext_swap_inode_data() switches the inode to extents and copies the
> tree root into it before it frees the old indirect block map, so it can
> return an error after the swap has already happened.  The copied root
> points at index blocks that tmp_inode allocated, and free_ext_block()
> walks that same tree and frees them, leaving the migrated inode with a
> tree node that the block bitmap considers free.
> 
> Only free the tmp_inode tree when the inode has not been switched to
> extents, which is exactly the case where the swap did not happen.
> 
> Fixes: c14c6fd5c56a ("ext4: Add EXT4_IOC_MIGRATE ioctl")
> Signed-off-by: Yichong Chen <chenyichong@uniontech.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260918101240.3721805-1-chenyichong@uniontech.com?part=1