cifs: pass instantiated filp back after open call

The current scheme of sticking open files on a list and assuming that
cifs_open will scoop them off of it is broken and leads to "Busy
inodes after umount..." errors at unmount time.

The problem is that there is no guarantee that cifs_open will always
be called after a ->lookup or ->create operation. If there are
permissions or other problems, then it's quite likely that it *won't*
be called.

Fix this by fully instantiating the filp whenever the file is created
and pass that filp back to the VFS. If there is a problem, the VFS
can clean up the references.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-and-Tested-by: Suresh Jayaraman <sjayaraman@suse.de>

1 files changed, 27 insertions, 8 deletions

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index f49afb9980e7..e7ae78b66fa1 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -25,6 +25,7 @@
 #include <linux/slab.h>
 #include <linux/namei.h>
 #include <linux/mount.h>
+#include <linux/file.h>
 #include "cifsfs.h"
 #include "cifspdu.h"
 #include "cifsglob.h"
@@ -184,6 +185,8 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle,
         }
         write_unlock(&GlobalSMBSeslock);
 
+        file->private_data = pCifsFile;
+
         return pCifsFile;
 }
 
@@ -463,14 +466,22 @@ cifs_create_set_dentry:
 
         if (newinode && nd && (nd->flags & LOOKUP_OPEN)) {
                 struct cifsFileInfo *pfile_info;
-                /*
-                 * cifs_fill_filedata() takes care of setting cifsFileInfo
-                 * pointer to file->private_data.
-                 */
-                pfile_info = cifs_new_fileinfo(newinode, fileHandle, NULL,
+                struct file *filp;
+
+                filp = lookup_instantiate_filp(nd, direntry, generic_file_open);
+                if (IS_ERR(filp)) {
+                        rc = PTR_ERR(filp);
+                        CIFSSMBClose(xid, tcon, fileHandle);
+                        goto cifs_create_out;
+                }
+
+                pfile_info = cifs_new_fileinfo(newinode, fileHandle, filp,
                                                nd->path.mnt, oflags);
-                if (pfile_info == NULL)
+                if (pfile_info == NULL) {
+                        fput(filp);
+                        CIFSSMBClose(xid, tcon, fileHandle);
                         rc = -ENOMEM;
+                }
         } else {
                 CIFSSMBClose(xid, tcon, fileHandle);
         }
@@ -717,15 +728,23 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
                         direntry->d_op = &cifs_dentry_ops;
                 d_add(direntry, newInode);
                 if (posix_open) {
-                        cfile = cifs_new_fileinfo(newInode, fileHandle, NULL,
+                        filp = lookup_instantiate_filp(nd, direntry,
+                                                       generic_file_open);
+                        if (IS_ERR(filp)) {
+                                rc = PTR_ERR(filp);
+                                CIFSSMBClose(xid, pTcon, fileHandle);
+                                goto lookup_out;
+                        }
+
+                        cfile = cifs_new_fileinfo(newInode, fileHandle, filp,
                                                   nd->path.mnt,
                                                   nd->intent.open.flags);
                         if (cfile == NULL) {
+                                fput(filp);
                                 CIFSSMBClose(xid, pTcon, fileHandle);
                                 rc = -ENOMEM;
                                 goto lookup_out;
                         }
-                        filp = lookup_instantiate_filp(nd, direntry, NULL);
                 }
                 /* since paths are not looked up by component - the parent
                    directories are presumed to be good here */