[PATCH] xfs_io: fix fiemap loop continuation

[Dave Chinner]

From: Dave Chinner <dchinner at redhat.com>

From: Dave Chinner <dchinner at redhat.com>

When the fiemap command needs to retrieve more extents from the
kernel via a subsequent IO, it calculates the next logical block to
retrieve in file system block units. the fiemap needs the start
offset in bytes, not filesystem blocks.  Hence if the fiemap command
can loop forever retrieving the same blocks if the logical offset
offset of the next block in filesystem block units is smaller than
the number of bytes in a filessytem block. i.e. it will just loop
retreiving the first 32 extents from offset block zero.

Signed-off-by: Dave Chinner <dchinner at redhat.com>
---
 io/fiemap.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/io/fiemap.c b/io/fiemap.c
index 066e693..99296dd 100644
--- a/io/fiemap.c
+++ b/io/fiemap.c
@@ -108,7 +108,7 @@ print_verbose(
 	       boff_w, bbuf, tot_w, len, flg_w, flgbuf);
 
 	(*cur_extent)++;
-	*last_logical = lstart + len;
+	*last_logical = extent->fe_logical + extent->fe_length;
 }
 
 static void
@@ -151,7 +151,7 @@ print_plain(
 	else
 		printf("\n");
 	(*cur_extent)++;
-	*last_logical = lstart + len;
+	*last_logical = extent->fe_logical + extent->fe_length;
 }
 
 int
@@ -252,7 +252,7 @@ fiemap_f(
 		memset(fiemap, 0, map_size);
 		fiemap->fm_flags = fiemap_flags;
 		fiemap->fm_start = last_logical;
-		fiemap->fm_length = -1;
+		fiemap->fm_length = -1LL;
 		fiemap->fm_extent_count = num_extents;
 
 		ret = ioctl(file->fd, FS_IOC_FIEMAP, (unsigned long)fiemap);
-- 
1.7.8.3