On Wed, Dec 04, 2024 at 10:14:50PM -0800, Darrick J. Wong wrote:
The function opportunistically moves sc->tempip from the regular directory tree to the metadata directory tree if sc->ip is part of the metadata directory tree. However, the scrub setup functions grab sc->ip and create sc->tempip before we actually get around to checking if the file is the right type for the scrubber.
IOWs, you can invoke the symlink scrubber with the file handle of a subdirectory in the metadir. xrep_setup_symlink will create a temporary symlink file, xrep_tempfile_adjust_directory_tree will foolishly try to set the METADATA flag on the temp symlink, which trips the inode verifier in the inode item precommit, which shuts down the filesystem when expensive checks are turned on. If they're /not/ turned on, then xchk_symlink will return ENOENT when it sees that it's been passed a symlink.
Maybe just write this down in a big fat comment?