From cababeac915a218b3902aac772b1786068e8e2f3 Mon Sep 17 00:00:00 2001 From: Gabriel Krisman Bertazi Date: Wed, 19 Aug 2020 16:07:31 -0400 Subject: [PATCH] f2fs: Return EOF on unaligned end of file DIO read [ Upstream commit 20d0a107fb35f37578b919f62bd474d6d358d579 ] Reading past end of file returns EOF for aligned reads but -EINVAL for unaligned reads on f2fs. While documentation is not strict about this corner case, most filesystem returns EOF on this case, like iomap filesystems. This patch consolidates the behavior for f2fs, by making it return EOF(0). it can be verified by a read loop on a file that does a partial read before EOF (A file that doesn't end at an aligned address). The following code fails on an unaligned file on f2fs, but not on btrfs, ext4, and xfs. while (done < total) { ssize_t delta = pread(fd, buf + done, total - done, off + done); if (!delta) break; ... } It is arguable whether filesystems should actually return EOF or -EINVAL, but since iomap filesystems support it, and so does the original DIO code, it seems reasonable to consolidate on that. Signed-off-by: Gabriel Krisman Bertazi Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin --- fs/f2fs/data.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index c81a1f3f0a10..c63f5e32630e 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -2490,6 +2490,9 @@ static int check_direct_IO(struct inode *inode, struct iov_iter *iter, unsigned long align = offset | iov_iter_alignment(iter); struct block_device *bdev = inode->i_sb->s_bdev; + if (iov_iter_rw(iter) == READ && offset >= i_size_read(inode)) + return 1; + if (align & blocksize_mask) { if (bdev) blkbits = blksize_bits(bdev_logical_block_size(bdev));