On 29/10/2019 10.17, Konstantin Khlebnikov wrote:
If inode->i_blocks is zero then ext4_evict_inode() skips ext4_truncate(). Delayed allocation extents are freed later in ext4_clear_inode() but this happens when quota reference is already dropped. This leads to leak of reserved space in quota block, which disappears after umount-mount. This seems broken for a long time but worked somehow until recent changes in delayed allocation.
FYI, perf cannot correctly parse related perf events without this: https://lore.kernel.org/lkml/157228145325.7530.4974461761228678289.stgit@buzz/
