[PATCH V2] f2fs: fix to adjust appropriate length for fiemap

[Zhiguo Niu]

If user give a file size as "length" parameter for fiemap
operations, but if this size is non-block size aligned,
it will show 2 segments fiemap results even this whole file
is contiguous on disk, such as the following results:

 ./f2fs_io fiemap 0 19034 ylog/analyzer.py
Fiemap: offset = 0 len = 19034
        logical addr.    physical addr.   length           flags
0       0000000000000000 0000000020baa000 0000000000004000 00001000
1       0000000000004000 0000000020bae000 0000000000001000 00001001

after this patch:
./f2fs_io fiemap 0 19034 ylog/analyzer.py
Fiemap: offset = 0 len = 19034
    logical addr.    physical addr.   length           flags
0    0000000000000000 00000000315f3000 0000000000005000 00001001

Signed-off-by: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>
---
V2: correct commit msg according to Chao's questions
f2fs_io has been modified for testing, the length for fiemap is
real file size, not block number
---
 fs/f2fs/data.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 306b86b0..9fc229d 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1966,8 +1966,8 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 			goto out;
 	}
 
-	if (bytes_to_blks(inode, len) == 0)
-		len = blks_to_bytes(inode, 1);
+	if (len & (blks_to_bytes(inode, 1) - 1))
+		len = round_up(len, blks_to_bytes(inode, 1));
 
 	start_blk = bytes_to_blks(inode, start);
 	last_blk = bytes_to_blks(inode, start + len - 1);
-- 
1.9.1