svn commit: r274410 - head/usr.bin/mkimg

[Marcel Moolenaar]

Author: marcel
Date: Wed Nov 12 00:10:27 2014
New Revision: 274410
URL: https://svnweb.freebsd.org/changeset/base/274410

Log:
  SEEK_DATA has interesting behaviour for sparse files on ZFS.  A sparse file
  with 128K of random data and truncated to 800K can have SEEK_DATA return -1
  when given an offset of 128K. On UFS, the SEEK_DATA returns 800K (the size
  of the file). SEEK_HOLE on ZFS seems to behave the same as UFS.
  
  To handle this, map -1 to the size of the file (`end') when lseek returns
  this for either SEEK_HOLE or SEEK_DATA. When sparse files are not supported
  by the file system both `hole' and `data' will now be equal to `end' and we
  will treat the entire file as data. This way, the -1 return for SEEK_DATA
  on ZFS will end up doing the right thing.
  
  Reported by: gjb@
  
  MFC after:	3 days

Modified:
  head/usr.bin/mkimg/image.c

Modified: head/usr.bin/mkimg/image.c
==============================================================================
--- head/usr.bin/mkimg/image.c	Tue Nov 11 23:55:37 2014	(r274409)
+++ head/usr.bin/mkimg/image.c	Wed Nov 12 00:10:27 2014	(r274410)
@@ -405,16 +405,18 @@ image_copyin_mapped(lba_t blk, int fd, u
 	error = 0;
 	while (!error && cur < end) {
 		hole = lseek(fd, cur, SEEK_HOLE);
+		if (hole == -1)
+			hole = end;
 		data = lseek(fd, cur, SEEK_DATA);
+		if (data == -1)
+			data = end;
 
 		/*
 		 * Treat the entire file as data if sparse files
 		 * are not supported by the underlying file system.
 		 */
-		if (hole == -1 && data == -1) {
+		if (hole == end && data == end)
 			data = cur;
-			hole = end;
-		}
 
 		if (cur == hole && data > hole) {
 			hole = pos;