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author | trasz <trasz@FreeBSD.org> | 2014-08-31 21:51:01 +0000 |
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committer | trasz <trasz@FreeBSD.org> | 2014-08-31 21:51:01 +0000 |
commit | 2ded039a6da22e85917388ed0b611e4858d05a72 (patch) | |
tree | abf99ae68023542be3b688570626d72fde248cca | |
parent | 87f90af6e4825d0640770331d4a17eb12fa2625b (diff) | |
download | FreeBSD-src-2ded039a6da22e85917388ed0b611e4858d05a72.zip FreeBSD-src-2ded039a6da22e85917388ed0b611e4858d05a72.tar.gz |
MFC r270399:
Add comment explaining one of the quirks in autofs.
Sponsored by: The FreeBSD Foundation
-rw-r--r-- | sys/fs/autofs/autofs.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/sys/fs/autofs/autofs.c b/sys/fs/autofs/autofs.c index d3ea03d..d5a6892 100644 --- a/sys/fs/autofs/autofs.c +++ b/sys/fs/autofs/autofs.c @@ -595,6 +595,14 @@ autofs_open(struct cdev *dev, int flags, int fmt, struct thread *td) { sx_xlock(&sc->sc_lock); + /* + * We must never block automountd(8) and its descendants, and we use + * session ID to determine that: we store session id of the process + * that opened the device, and then compare it with session ids + * of triggering processes. This means running a second automountd(8) + * instance would break the previous one. The check below prevents + * it from happening. + */ if (sc->sc_dev_opened) { sx_xunlock(&sc->sc_lock); return (EBUSY); |