dax: assert that i_rwsem is held exclusive for writes

Make sure all callers follow the same locking protocol, given that DAX
transparantly replaced the normal buffered I/O path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Christoph Hellwig 2017-02-08 14:43:13 -05:00 committed by Theodore Ts'o
parent ff5462e39c
commit 168316db35

View File

@ -1061,8 +1061,12 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
loff_t pos = iocb->ki_pos, ret = 0, done = 0;
unsigned flags = 0;
if (iov_iter_rw(iter) == WRITE)
if (iov_iter_rw(iter) == WRITE) {
lockdep_assert_held_exclusive(&inode->i_rwsem);
flags |= IOMAP_WRITE;
} else {
lockdep_assert_held(&inode->i_rwsem);
}
while (iov_iter_count(iter)) {
ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops,