fix

2 files changed, 18 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 5fb7183..08c2c54 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2006-03-16  Miklos Szeredi <miklos@szeredi.hu>
+
+	* Don't unmount if already unmounted.  This fixes a problem seen
+	in the following situation: Lazy unmount a busy filesystem; Mount
+	a new one in top; When the first finally unmounts, the second also
+	unmounts.  Reported by Franco Broi
+
 2006-03-15  Miklos Szeredi <miklos@szeredi.hu>
 
 	* lowlevel lib: use indirect function calls instead of a
diff --git a/lib/mount.c b/lib/mount.c
index a1875f0..5c568e9 100644
--- a/lib/mount.c
+++ b/lib/mount.c
@@ -16,6 +16,7 @@
 #include <stddef.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <sys/poll.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <sys/wait.h>
@@ -174,13 +175,21 @@ void fuse_unmount_compat22(const char *mountpoint)
 void fuse_unmount(const char *mountpoint, int fd)
 {
     const char *mountprog = FUSERMOUNT_PROG;
+    struct pollfd pfd;
+    int res;
     int pid;
 
-    (void) fd;
-
     if (!mountpoint)
         return;
 
+    pfd.fd = fd;
+    pfd.events = 0;
+    res = poll(&pfd, 1, 0);
+    /* If file poll returns POLLERR on the device file descriptor,
+       then the filesystem is already unmounted */
+    if (res == 1 && (pfd.revents & POLLERR))
+        return;
+
 #ifdef HAVE_FORK
     pid = fork();
 #else