Invalidate readahead data properly when file closed, but other client changed it on server

fs/cifs/file.c

@@ -171,7 +171,26 @@ cifs_open(struct inode *inode, struct file *file)
 				list_add(&pCifsFile->flist,&pCifsInode->openFileList);
 				write_unlock(&GlobalSMBSeslock);
 				write_unlock(&file->f_owner.lock);
-
+				if(pCifsInode->clientCanCacheRead) {
+					/* we have the inode open somewhere else
+					   no need to discard cache data */
+				} else {
+					if(buf) {
+					/* BB need same check in cifs_create too? */
+
+					/* if not oplocked, invalidate inode pages if mtime 
+					   or file size changed */
+						struct timespec temp;
+						temp = cifs_NTtimeToUnix(le64_to_cpu(buf->LastWriteTime));
+						if(timespec_equal(&file->f_dentry->d_inode->i_mtime,&temp) && 
+							(file->f_dentry->d_inode->i_size == le64_to_cpu(buf->EndOfFile))) {
+							cFYI(1,("inode unchanged on server"));
+						} else {
+							cFYI(1,("invalidating remote inode since open detected it changed"));
+							invalidate_remote_inode(file->f_dentry->d_inode);
+						}
+					}
+				}
 				if (pTcon->ses->capabilities & CAP_UNIX)
 					rc = cifs_get_inode_info_unix(&file->f_dentry->d_inode,
 						full_path, inode->i_sb);

fs/cifs/inode.c

@@ -627,7 +627,7 @@ cifs_revalidate(struct dentry *direntry)
 
 	if(timespec_equal(&local_mtime,&direntry->d_inode->i_mtime) && 
 		(local_size == direntry->d_inode->i_size)) {
-		cFYI(1,("inode unchanged on server"));
+		cFYI(1,("cifs_revalidate - inode unchanged"));
 	} else {
 		/* file may have changed on server */
 		if(cifsInode->clientCanCacheRead) {
@@ -648,7 +648,12 @@ cifs_revalidate(struct dentry *direntry)
 	}
 	if(invalidate_inode) {
 		filemap_fdatawait(direntry->d_inode->i_mapping);
-		/* invalidate_remote_inode(direntry->d_inode); */ /* BB fixme */
+		/* may eventually have to do this for open files too */
+		if(list_empty(&(cifsInode->openFileList))) {
+			/* Has changed on server - flush read ahead pages */
+			cFYI(1,("Invalidating read ahead data on closed file"));
+			invalidate_remote_inode(direntry->d_inode);
+		}
 	}