btrfs-progs: report failure when resize ioctl fails

The BTRFS_IOC_RESIZE ioctl returns 0 on success, negative for POSIX
errors, and positive for btrfs-specific errors.

If resize fails with a btrfs-specific error, decode the error and
report it.  If we can't decode the error, report its numeric value so
that the userspace tool is not instantly useless when a new error code
is defined in the kernel.

Exit with non-zero status on any resize error.  This is very important
for scripts that will shrink the underlying storage when btrfs reports
success!

Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org
Signed-off-by: David Sterba <dsterba@suse.cz>

diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index 2cace75..b93bb33 100644 (file)
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -1278,6 +1278,18 @@ static int cmd_resize(int argc, char **argv)
                fprintf(stderr, "ERROR: unable to resize '%s' - %s\n", 
                        path, strerror(e));
                return 1;
+       } else if (res > 0) {
+               const char *err_str = btrfs_err_str(res);
+
+               if (err_str) {
+                       fprintf(stderr, "ERROR: btrfs error resizing '%s' - %s\n",
+                               path, err_str);
+               } else {
+                       fprintf(stderr,
+                       "ERROR: btrfs error resizing '%s' - unknown btrfs_err_code %d\n",
+                               path, res);
+               }
+               return 1;
        }
        return 0;
 }