Print mount/umount errors

Because we are dependent of the system mount/umount utilities to
ensure correct mtab locking, we should not suppress their error
output.  During a successful mount/umount they will be silent,
but during a failure the error message they print is the only sure
way to know why a mount failed.  This is because the (u)mount(8)
return code does not contain the result of the system call issued.
The only way to clearly idenify why thing failed is to rely on
the error message printed by the tool.

Longer term once libmount is available we can issue the mount/umount
system calls within the tool and still be ensured correct mtab locking.

Closed #107

diff --git a/include/libzfs.h b/include/libzfs.h
index 082b690..e0c6950 100644 (file)
--- a/include/libzfs.h
+++ b/include/libzfs.h
@@ -675,7 +675,10 @@ extern int zfs_nicestrtonum(libzfs_handle_t *, const char *, uint64_t *);
 /*
  * Utility functions to run an external process.
  */
-int libzfs_run_process(const char *, char **);
+#define        STDOUT_VERBOSE  0x01
+#define        STDERR_VERBOSE  0x02
+
+int libzfs_run_process(const char *, char **, int flags);
 int libzfs_load_module(const char *);
 
 /*

diff --git a/lib/libzfs/libzfs_mount.c b/lib/libzfs/libzfs_mount.c
index a1faf49..1dc58f9 100644 (file)
--- a/lib/libzfs/libzfs_mount.c
+++ b/lib/libzfs/libzfs_mount.c
@@ -269,7 +269,7 @@ do_mount(const char *src, const char *mntpt, char *opts)
        int rc;
 
        /* Return only the most critical mount error */
-       rc = libzfs_run_process(argv[0], argv);
+       rc = libzfs_run_process(argv[0], argv, STDOUT_VERBOSE|STDERR_VERBOSE);
        if (rc) {
                if (rc & MOUNT_FILEIO)
                        return EIO;
@@ -310,7 +310,7 @@ do_unmount(const char *mntpt, int flags)
        }
 
        argv[count] = (char *)mntpt;
-       rc = libzfs_run_process(argv[0], argv);
+       rc = libzfs_run_process(argv[0], argv, STDOUT_VERBOSE|STDERR_VERBOSE);
 
        return (rc ? EINVAL : 0);
 }
@@ -414,8 +414,10 @@ zfs_mount(zfs_handle_t *zhp, const char *options, int flags)
 static int
 unmount_one(libzfs_handle_t *hdl, const char *mountpoint, int flags)
 {
-       if (do_unmount(mountpoint, flags) != 0) {
-               zfs_error_aux(hdl, strerror(errno));
+       int error;
+
+       error = do_unmount(mountpoint, flags);
+       if (error != 0) {
                return (zfs_error_fmt(hdl, EZFS_UMOUNTFAILED,
                    dgettext(TEXT_DOMAIN, "cannot unmount '%s'"),
                    mountpoint));

diff --git a/lib/libzfs/libzfs_util.c b/lib/libzfs/libzfs_util.c
index 163cd16..da1b9bc 100644 (file)
--- a/lib/libzfs/libzfs_util.c
+++ b/lib/libzfs/libzfs_util.c
@@ -632,15 +632,19 @@ libzfs_module_loaded(const char *module)
 }
 
 int
-libzfs_run_process(const char *path, char *argv[])
+libzfs_run_process(const char *path, char *argv[], int flags)
 {
        pid_t pid;
        int rc;
 
        pid = vfork();
        if (pid == 0) {
-               close(1);
-               close(2);
+               if (!(flags & STDOUT_VERBOSE))
+                       close(STDOUT_FILENO);
+
+               if (!(flags & STDERR_VERBOSE))
+                       close(STDERR_FILENO);
+
                (void) execvp(path, argv);
                _exit(-1);
        } else if (pid > 0) {
@@ -665,7 +669,7 @@ libzfs_load_module(const char *module)
        if (libzfs_module_loaded(module))
                return 0;
 
-       return libzfs_run_process("/sbin/modprobe", argv);
+       return libzfs_run_process("/sbin/modprobe", argv, 0);
 }
 
 libzfs_handle_t *