Commit 769f5267 authored by Bart Van Assche's avatar Bart Van Assche Committed by Christoph Hellwig
Browse files

configfs: restore the kernel v5.13 text attribute write behavior 



Instead of appending new text attribute data at the offset specified by the
write() system call, only pass the newly written data to the .store()
callback.

Reported-by: default avatarBodo Stroesser <bostroesser@gmail.com>
Tested-by: default avatarBodo Stroesser <bostroesser@gmail.com>
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 36a21d51

fs/configfs/file.c

+6 −12
Original line number Diff line number Diff line
@@ -177,28 +177,22 @@ static ssize_t configfs_bin_read_iter(struct kiocb *iocb, struct iov_iter *to) 
	return retval;

}



/* Fill [buffer, buffer + pos) with data coming from @from. */

static int fill_write_buffer(struct configfs_buffer *buffer, loff_t pos,

/* Fill @buffer with data coming from @from. */

static int fill_write_buffer(struct configfs_buffer *buffer,

			     struct iov_iter *from)

{

	loff_t to_copy;

	int copied;

	u8 *to;



	if (!buffer->page)

		buffer->page = (char *)__get_free_pages(GFP_KERNEL, 0);

	if (!buffer->page)

		return -ENOMEM;



	to_copy = SIMPLE_ATTR_SIZE - 1 - pos;

	if (to_copy <= 0)

		return 0;

	to = buffer->page + pos;

	copied = copy_from_iter(to, to_copy, from);

	copied = copy_from_iter(buffer->page, SIMPLE_ATTR_SIZE - 1, from);

	buffer->needs_read_fill = 1;

	/* if buf is assumed to contain a string, terminate it by \0,

	 * so e.g. sscanf() can scan the string easily */

	to[copied] = 0;

	buffer->page[copied] = 0;

	return copied ? : -EFAULT;

}
@@ -227,10 +221,10 @@ static ssize_t configfs_write_iter(struct kiocb *iocb, struct iov_iter *from) 
{

	struct file *file = iocb->ki_filp;

	struct configfs_buffer *buffer = file->private_data;

	ssize_t len;

	int len;



	mutex_lock(&buffer->mutex);

	len = fill_write_buffer(buffer, iocb->ki_pos, from);

	len = fill_write_buffer(buffer, from);

	if (len > 0)

		len = flush_write_buffer(file, buffer, len);

	if (len > 0)