CIFS: Implement cifs_file_strict_mmap (try #2)

Invalidate inode mapping if we don't have at least Level II oplock.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 5790fab7349b..0b32377ef8b7 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1769,6 +1769,21 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
         return total_read;
 }
 
+int cifs_file_strict_mmap(struct file *file, struct vm_area_struct *vma)
+{
+        int rc, xid;
+        struct inode *inode = file->f_path.dentry->d_inode;
+
+        xid = GetXid();
+
+        if (!CIFS_I(inode)->clientCanCacheRead)
+                cifs_invalidate_mapping(inode);
+
+        rc = generic_file_mmap(file, vma);
+        FreeXid(xid);
+        return rc;
+}
+
 int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
         int rc, xid;