I have an ext3 image that was fully validated by e2fsck, but btrfs-convert seems to loop on it, I aborted it after it copied >10M inodes of ~3.5M inodes. Observing it with strace it did in fact seem like the same files were converted multiple times, though with >3.5M files present this isn't trivial to say (but it seems to be doing directory by directory, and I saw files from the same directory hours apart.)
I can't really provide the image (it contains private data and is ~400GiB), but I can try things with it.
I have an ext3 image that was fully validated by e2fsck, but btrfs-convert seems to loop on it, I aborted it after it copied >10M inodes of ~3.5M inodes. Observing it with strace it did in fact seem like the same files were converted multiple times, though with >3.5M files present this isn't trivial to say (but it seems to be doing directory by directory, and I saw files from the same directory hours apart.)
I can't really provide the image (it contains private data and is ~400GiB), but I can try things with it.