[PATCH v3 5/5] xfs: disable map_sync for virtio pmem

Pankaj Gupta
2019-01-09T14:47:36Z

Virtio pmem provides asynchronous host page cache flush
mechanism. we don't support 'MAP_SYNC' with virtio pmem
and xfs.

Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
---
fs/xfs/xfs_file.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index e474250..eae4aa4 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1190,6 +1190,14 @@ xfs_file_mmap(
if (!IS_DAX(file_inode(filp)) && (vma->vm_flags & VM_SYNC))
return -EOPNOTSUPP;

+ /* We don't support synchronous mappings with guest direct access
+ * and virtio based host page cache mechanism.
+ */
+ if (IS_DAX(file_inode(filp)) && virtio_pmem_host_cache_enabled(
+ xfs_find_daxdev_for_inode(file_inode(filp))) &&
+ (vma->vm_flags & VM_SYNC))
+ return -EOPNOTSUPP;
+
file_accessed(filp);
vma->vm_ops = &xfs_file_vm_ops;
if (IS_DAX(file_inode(filp)))
--
2.9.3