[PATCH 5/6] CIFS: Make cifs_file_map work with strict cache mode (try #3)

[Pavel Shilovsky <piastryyy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Invalidate inode if we don't have at least Level II oplock and strict
cache mode switched on.

Signed-off-by: Pavel Shilovsky <piastryyy-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 fs/cifs/file.c |   20 +++++++++++++++-----
 1 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index d216879..e9f2fae 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1812,14 +1812,24 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
 int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	int rc, xid;
+	struct inode *inode = file->f_path.dentry->d_inode;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 
 	xid = GetXid();
-	rc = cifs_revalidate_file(file);
-	if (rc) {
-		cFYI(1, "Validation prior to mmap failed, error=%d", rc);
-		FreeXid(xid);
-		return rc;
+
+	if (!CIFS_I(inode)->clientCanCacheRead &&
+	    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO))
+		cifs_invalidate_mapping(inode);
+	else {
+		rc = cifs_revalidate_file(file);
+		if (rc) {
+			cFYI(1, "Validation prior to mmap failed, error=%d",
+			     rc);
+			FreeXid(xid);
+			return rc;
+		}
 	}
+
 	rc = generic_file_mmap(file, vma);
 	FreeXid(xid);
 	return rc;
-- 
1.7.3.2