ext4: fix off-by-in in loop termination in ext4_find_unwritten_pgoff()

There is an off-by-one error in loop termination conditions in
ext4_find_unwritten_pgoff() since 'end' may index a page beyond end of
desired range if 'endoff' is page aligned. It doesn't have any visible
effects but still it is good to fix it.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index bbea2dc..2b00bf8 100644 (file)
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -474,7 +474,7 @@ static int ext4_find_unwritten_pgoff(struct inode *inode,
        endoff = (loff_t)end_blk << blkbits;
 
        index = startoff >> PAGE_SHIFT;
-       end = endoff >> PAGE_SHIFT;
+       end = (endoff - 1) >> PAGE_SHIFT;
 
        pagevec_init(&pvec, 0);
        do {