cifs: Allow directIO read/write during cache=strict

Currently cifs have all or nothing approach for directIO operations. cache=strict mode does not allow directIO while cache=none mode performs all the operations as directIO even when user does not specify O_DIRECT flag. This patch enables strict cache mode to honour directIO semantics.

Signed-off-by Namjae Jeon <[email protected]>

Signed-off-by Ashish Sangwan <[email protected]>

---
*Changelog
v2:
- Also consider CIFS_MOUNT_NO_BRL flag.

 fs/cifs/dir.c  |    8 ++++++++
 fs/cifs/file.c |    8 ++++++++
 2 files changed, 16 insertions(+), 0 deletions(-)

fs/cifs/dir.c +8 -0

index 3db0c5f..6cbd9c6 100644
@@ -497,6 +497,14 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry,
                goto out;
        }
 
+       if (file->f_flags & O_DIRECT &&
+           CIFS_SB(inode->i_sb)->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) {
+               if (CIFS_SB(inode->i_sb)->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
+                       file->f_op = &cifs_file_direct_nobrl_ops;
+               else
+                       file->f_op = &cifs_file_direct_ops;
+               }
+
        file_info = cifs_new_fileinfo(&fid, file, tlink, oplock);
        if (file_info == NULL) {
                if (server->ops->close)

fs/cifs/file.c +8 -1

index bee733e..2e3720f 100644
@@ -467,6 +467,14 @@ int cifs_open(struct inode *inode, struct file *file)
        cifs_dbg(FYI, "inode = 0x%p file flags are 0x%x for %s\n",
                 inode, file->f_flags, full_path);
 
+       if (file->f_flags & O_DIRECT &&
+           cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) {
+               if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
+                       file->f_op = &cifs_file_direct_nobrl_ops;
+               else
+                       file->f_op = &cifs_file_direct_ops;
+       }
+
        if (server->oplocks)
                oplock = REQ_OPLOCK;
        else
--

1.7.7