autofs4: deal with autofs4_write/autofs4_write races
authorAl Viro <viro@zeniv.linux.org.uk>
Wed, 11 Jan 2012 03:35:38 +0000 (22:35 -0500)
committerAl Viro <viro@zeniv.linux.org.uk>
Wed, 11 Jan 2012 05:20:12 +0000 (00:20 -0500)
commitd668dc56631da067540b2494d2a1f29ff7b5f15a
tree303ad17208838e8b9b1752f9427d55c84555f0f0
parent8753333266be67ff3a984ac1f6566d31c260bee4
autofs4: deal with autofs4_write/autofs4_write races

Just serialize the actual writing of packets into pipe on
a new mutex, independent from everything else in the locking
hierarchy.  As soon as something has started feeding a piece
of packet into the pipe to daemon, we *want* everything else
about to try the same to wait until we are done.

Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs/autofs4/autofs_i.h
fs/autofs4/inode.c
fs/autofs4/waitq.c