growfs: don't reopen fds unnecessarily

Instead, just open the mount fd once, and then operate on fds only.

1 files changed, 15 insertions, 8 deletions

diff --git a/src/partition/growfs.c b/src/partition/growfs.c
index cd85946812..15cb24d151 100644
--- a/src/partition/growfs.c
+++ b/src/partition/growfs.c
@@ -85,16 +85,23 @@ static int resize_crypt_luks_device(dev_t devno, const char *fstype, dev_t main_
 }
 #endif
 
-static int maybe_resize_underlying_device(const char *mountpath, dev_t main_devno) {
+static int maybe_resize_underlying_device(
+                int mountfd,
+                const char *mountpath,
+                dev_t main_devno) {
+
         _cleanup_free_ char *fstype = NULL, *devpath = NULL;
         dev_t devno;
         int r;
 
+        assert(mountfd >= 0);
+        assert(mountpath);
+
 #if HAVE_LIBCRYPTSETUP
         cryptsetup_enable_logging(NULL);
 #endif
 
-        r = get_block_device_harder(mountpath, &devno);
+        r = get_block_device_harder_fd(mountfd, &devno);
         if (r < 0)
                 return log_error_errno(r, "Failed to determine underlying block device of \"%s\": %m",
                                        mountpath);
@@ -214,7 +221,11 @@ static int run(int argc, char *argv[]) {
         if (r == 0)
                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "\"%s\" is not a mount point: %m", arg_target);
 
-        r = get_block_device(arg_target, &devno);
+        mountfd = open(arg_target, O_RDONLY|O_CLOEXEC|O_DIRECTORY);
+        if (mountfd < 0)
+                return log_error_errno(errno, "Failed to open \"%s\": %m", arg_target);
+
+        r = get_block_device_fd(mountfd, &devno);
         if (r == -EUCLEAN)
                 return btrfs_log_dev_root(LOG_ERR, r, arg_target);
         if (r < 0)
@@ -222,14 +233,10 @@ static int run(int argc, char *argv[]) {
         if (devno == 0)
                 return log_error_errno(SYNTHETIC_ERRNO(ENODEV), "File system \"%s\" not backed by block device.", arg_target);
 
-        r = maybe_resize_underlying_device(arg_target, devno);
+        r = maybe_resize_underlying_device(mountfd, arg_target, devno);
         if (r < 0)
                 return r;
 
-        mountfd = open(arg_target, O_RDONLY|O_CLOEXEC|O_DIRECTORY);
-        if (mountfd < 0)
-                return log_error_errno(errno, "Failed to open \"%s\": %m", arg_target);
-
         r = device_path_make_major_minor(S_IFBLK, devno, &devpath);
         if (r < 0)
                 return log_error_errno(r, "Failed to format device major/minor path: %m");