From e5465795cac48233c9b606a7a419f4190a91851e Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 24 May 2017 18:05:29 -0400 Subject: ext4: fix off-by-one error when writing back pages before dio read The 'lend' argument of filemap_write_and_wait_range() is inclusive, so we need to subtract 1 from pos + count. Note that 'count' is guaranteed to be nonzero since ext4_file_read_iter() returns early when given a 0 count. Fixes: 16c54688592c ("ext4: Allow parallel DIO reads") Signed-off-by: Eric Biggers Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara --- fs/ext4/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 7cd99de8c4ba..90b264928742 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3713,7 +3713,7 @@ static ssize_t ext4_direct_IO_read(struct kiocb *iocb, struct iov_iter *iter) */ inode_lock_shared(inode); ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, - iocb->ki_pos + count); + iocb->ki_pos + count - 1); if (ret) goto out_unlock; ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, -- cgit v1.2.1