btrfs-progs: defrag: set errno correctly in the callback

In case defrag fails, the errno is not properly reported everywhere but
rather the last value of 'e', which could be 0. Then we get confusing
error messages like:

ERROR: defrag failed on /path/to/file: Success

Reported-by: Adam Mizerski <adam@mizerski.pl>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index 76ea82e..90eccf7 100644 (file)
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -993,32 +993,35 @@ static int defrag_callback(const char *fpath, const struct stat *sb,
                int typeflag, struct FTW *ftwbuf)
 {
        int ret = 0;
-       int e = 0;
+       int err = 0;
        int fd = 0;
 
        if ((typeflag == FTW_F) && S_ISREG(sb->st_mode)) {
                if (defrag_global_verbose)
                        printf("%s\n", fpath);
                fd = open(fpath, O_RDWR);
-               if (fd < 0)
+               if (fd < 0) {
+                       err = errno;
                        goto error;
+               }
                ret = do_defrag(fd, defrag_global_fancy_ioctl, &defrag_global_range);
-               e = errno;
                close(fd);
-               if (ret && e == ENOTTY && defrag_global_fancy_ioctl) {
+               if (ret && errno == ENOTTY && defrag_global_fancy_ioctl) {
                        error("defrag range ioctl not "
                                "supported in this kernel, please try "
                                "without any options.");
                        defrag_global_errors++;
                        return ENOTTY;
                }
-               if (ret)
+               if (ret) {
+                       err = errno;
                        goto error;
+               }
        }
        return 0;
 
 error:
-       error("defrag failed on %s: %s", fpath, strerror(e));
+       error("defrag failed on %s: %s", fpath, strerror(err));
        defrag_global_errors++;
        return 0;
 }