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Commit 0d5b0cf2 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dave Chinner
Browse files

fs: update atime before I/O in generic_file_read_iter 



After the call to ->direct_IO the final reference to the file might have
been dropped by aio_complete already, and the call to file_accessed might
cause a use after free.

Instead update the access time before the I/O, similar to how we
update the time stamps before writes.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent a447d7cd

mm/filemap.c

+7 −7
Original line number Diff line number Diff line
@@ -1910,16 +1910,18 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) 
	if (iocb->ki_flags & IOCB_DIRECT) {

		struct address_space *mapping = file->f_mapping;

		struct inode *inode = mapping->host;

		struct iov_iter data = *iter;

		loff_t size;



		size = i_size_read(inode);

		retval = filemap_write_and_wait_range(mapping, iocb->ki_pos,

					iocb->ki_pos + count - 1);

		if (!retval) {

			struct iov_iter data = *iter;

			retval = mapping->a_ops->direct_IO(iocb, &data);

		}

		if (retval < 0)

			goto out;



		file_accessed(file);



		retval = mapping->a_ops->direct_IO(iocb, &data);

		if (retval > 0) {

			iocb->ki_pos += retval;

			iov_iter_advance(iter, retval);
@@ -1935,11 +1937,9 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) 
		 * DAX files, so don't bother trying.

		 */

		if (retval < 0 || !iov_iter_count(iter) || iocb->ki_pos >= size ||

		    IS_DAX(inode)) {

			file_accessed(file);

		    IS_DAX(inode))

			goto out;

	}

	}



	retval = do_generic_file_read(file, &iocb->ki_pos, iter, retval);

out: