SOLVED: [solved] m3u playlists were blank

[bleetube]

tl;dr I have a few hundred M3U playlists, each within the same folder of the tracks that they reference. I also had three playlists that reference tracks in subdirectories.  The ones that reference a track in the same directory show zero tracks in Jellyfin, while the playlists that reference tracks in subdirectories show all of their tracks.  Seems like a bug?  All of the playlists work in other music apps I've tried, including VLC. I've tested prepending "./" on the track filename in the M3U and that didn't make a difference. My playlists only work if they reference tracks from a parent directory. 

Some other useless details:

I recovered my old (Windows!) drive recovered on my desktop (Archlinux, btw) and ofc I fixed CRLF return lines with good ol' dos2unix, and I sed out the wrong slashes with the right ones:

find . -iname '*.m3u8' -exec dos2unix "{}" \;
find . -iname '*.m3u8' -exec sed -i 's/\\/\//g' "{}" \;

Anyway, after that only three out of hundreds of M3U playlists showed their tracks in Jellyfin. I've been through this loop over and over for the last hour:

* tweaking a playlist
* pressing "Scan All Libraries" (I only have the one, and it basically finishes instantly. Also, I've confirmed that the scans do take place by renaming the playlist slightly.)
* reload the jellyfin webui
* click the playlist name (or the new name if I renamed it)
* still zero tracks
* repeat

[bleetube]

Oops! Coming back to this today I noticed I didn't have the file permission/ownership on these directories. After I fixed that, the playlists all work now.