The fsmonitor daemon does not currently know about submodules and does
not know to filter out filesystem events that happen within a
submodule. If fsmonitor daemon is watching a super repo and a file is
modified within the working directory of a submodule, it will report
the change (as happening against the super repo). However, the client
will properly ignore these extra events, so performance may be affected
but it will not cause an incorrect result.
By default, the fsmonitor daemon refuses to work with network-mounted
repositories; this may be overridden by setting fsmonitor.allowRemote to
true. Note, however, that the fsmonitor daemon is not guaranteed to work
correctly with all network-mounted repositories, so such use is considered
experimental.
On Mac OS, the inter-process communication (IPC) between various Git
commands and the fsmonitor daemon is done via a Unix domain socket (UDS) — a
special type of file — which is supported by native Mac OS filesystems,
but not on network-mounted filesystems, NTFS, or FAT32. Other filesystems
may or may not have the needed support; the fsmonitor daemon is not guaranteed
to work with these filesystems and such use is considered experimental.
By default, the socket is created in the .git directory. However, if the
.git directory is on a network-mounted filesystem, it will instead be
created at $HOME/.git-fsmonitor-* unless $HOME itself is on a
network-mounted filesystem, in which case you must set the configuration
variable fsmonitor.socketDir to the path of a directory on a Mac OS native
filesystem in which to create the socket file.
If none of the above directories (.git, $HOME, or fsmonitor.socketDir)
is on a native Mac OS file filesystem the fsmonitor daemon will report an
error that will cause the daemon and the currently running command to exit.