df: 4TB+ support on 32 bits arch

Reported for Pascal Bellard.

function                                             old     new   delta
df_main                                             1054    1065     +11

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/coreutils/df.c b/coreutils/df.c
index 4076b5fec5dc8cce1f3466ce1060f350e7394592..1ed09d015c97bb437f77366542e19fb160b20f97 100644 (file)
--- a/coreutils/df.c
+++ b/coreutils/df.c
@@ -91,8 +91,6 @@ static unsigned long kscale(unsigned long b, unsigned long bs)
 int df_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int df_main(int argc UNUSED_PARAM, char **argv)
 {
-       unsigned long blocks_used;
-       unsigned blocks_percent_used;
        unsigned long df_disp_hr = 1024;
        int status = EXIT_SUCCESS;
        unsigned opt;
@@ -222,20 +220,29 @@ int df_main(int argc UNUSED_PARAM, char **argv)
                        s.f_frsize = s.f_bsize;
 
                if ((s.f_blocks > 0) || !mount_table || (opt & OPT_ALL)) {
+                       unsigned long long blocks_used;
+                       unsigned long long blocks_total;
+                       unsigned blocks_percent_used;
+
                        if (opt & OPT_INODE) {
                                s.f_blocks = s.f_files;
                                s.f_bavail = s.f_bfree = s.f_ffree;
                                s.f_frsize = 1;
-
                                if (df_disp_hr)
                                        df_disp_hr = 1;
                        }
                        blocks_used = s.f_blocks - s.f_bfree;
-                       blocks_percent_used = 0;
-                       if (blocks_used + s.f_bavail) {
-                               blocks_percent_used = (blocks_used * 100ULL
-                                               + (blocks_used + s.f_bavail)/2
-                                               ) / (blocks_used + s.f_bavail);
+                       blocks_total = blocks_used + s.f_bavail;
+                       blocks_percent_used = blocks_total; /* 0% if blocks_total == 0, else... */
+                       if (blocks_total != 0) {
+                               /* Downscale sizes for narrower division */
+                               unsigned u;
+                               while (blocks_total >= INT_MAX / 101) {
+                                       blocks_total >>= 1;
+                                       blocks_used >>= 1;
+                               }
+                               u = (unsigned)blocks_used * 100u + (unsigned)blocks_total / 2;
+                               blocks_percent_used = u / (unsigned)blocks_total;
                        }
 
                        /* GNU coreutils 6.10 skips certain mounts, try to be compatible.  */