diff --git a/HISTORY b/HISTORY
index 8f670868..3720ce55 100644
--- a/HISTORY
+++ b/HISTORY
@@ -4,8 +4,7 @@ SnapRAID HISTORY
 4.1 2013/9
 ==========
  * If the underline filesystem doesn't support the FIEMAP command,
-   automatically fallback to use FIBMAP and then the inode number for sorting
-   files.
+   automatically fallback to use FIBMAP for sorting files.
  * Fixes the import of content files from previous version of SnapRAID that
    are the result of an incomplete sync.
  * Added a new -C, --gen-conf option to generate a dummy configuration
diff --git a/unix.c b/unix.c
index f60b9d07..9033667d 100644
--- a/unix.c
+++ b/unix.c
@@ -141,14 +141,14 @@ int filephy(const char* path, struct stat* st, uint64_t* physical)
 	}
 
 	/* first try with FIEMAP */
-	/* if works for ext2, ext3, ext4, xfs */
+	/* if works for ext2, ext3, ext4, xfs, btrfs */
 	memset(&fm, 0, sizeof(fm));
 	fm.fiemap.fm_start = 0;
 	fm.fiemap.fm_length = ~0ULL;
 	fm.fiemap.fm_flags = FIEMAP_FLAG_SYNC; /* required to ensure that just created files report a valid address and not 0 */
 	fm.fiemap.fm_extent_count = 1; /* we are interested only at the first block */
 
-	if (ioctl(f, FS_IOC_FIEMAP, &fm) == 0) {
+	if (ioctl(f, FS_IOC_FIEMAP, &fm) != -1) {
 		*physical = fm.fiemap.fm_extents[0].fe_physical;
 		if (close(f) == -1)
 			return -1;
@@ -167,7 +167,7 @@ int filephy(const char* path, struct stat* st, uint64_t* physical)
 	/* it works for jfs, reiserfs, ntfs-3g */
 	/* in exfat it always returns 0, that it's anyway better than the fake inodes */
 	blknum = 0; /* first block */
-	if (ioctl(f, FIBMAP, &blknum) == 0) {
+	if (ioctl(f, FIBMAP, &blknum) != -1) {
 		*physical = blknum;
 		if (close(f) == -1)
 			return -1;