[PATCH 2/2] dax: assert that i_rwsem is held exclusive for writes
From: Christoph Hellwig <hch@lst.de>
Date: 2017-01-10 15:48:17
Also in:
linux-fsdevel, nvdimm
Subsystem:
filesystem direct access (dax), filesystems (vfs and infrastructure), the rest · Maintainers:
Dan Williams, Alexander Viro, Christian Brauner, Linus Torvalds
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> --- fs/dax.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/dax.c b/fs/dax.c
index 5c74f60..04734da 100644
--- a/fs/dax.c
+++ b/fs/dax.c@@ -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,
--
2.1.4