mkswap, readahead: stop using fdlength, it is reported to be unreliable

1 files changed, 9 insertions, 2 deletions

diff --git a/miscutils/readahead.c b/miscutils/readahead.c
index 7b375cfff..fb71ce85f 100644
--- a/miscutils/readahead.c
+++ b/miscutils/readahead.c
@@ -22,9 +22,16 @@ int readahead_main(int argc, char **argv)
         while (*++argv) {
                 int fd = open_or_warn(*argv, O_RDONLY);
                 if (fd >= 0) {
-                        int r = readahead(fd, 0, fdlength(fd));
+                        off_t len;
+                        int r;
+
+                        /* fdlength was reported to be unreliable - use seek */
+                        len = xlseek(fd, 0, SEEK_END);
+                        xlseek(fd, 0, SEEK_SET);
+                        r = readahead(fd, 0, len);
                         close(fd);
-                        if (r >= 0) continue;
+                        if (r >= 0)
+                                continue;
                 }
                 retval = EXIT_FAILURE;
         }