[CIFS] Allow null nd (as nfs server uses) on create

While creating a file on a server which supports unix extensions
such as Samba, if a file is being created which does not supply
nameidata (i.e. nd is null), cifs client can oops when calling
cifs_posix_open.

Signed-off-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 12 insertions, 8 deletions

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 4aa2fe3f535f..d791d0763a9c 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -182,13 +182,14 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle,
 }
 
 int cifs_posix_open(char *full_path, struct inode **pinode,
-                    struct vfsmount *mnt, int mode, int oflags,
-                    __u32 *poplock, __u16 *pnetfid, int xid)
+                        struct vfsmount *mnt, struct super_block *sb,
+                        int mode, int oflags,
+                        __u32 *poplock, __u16 *pnetfid, int xid)
 {
         int rc;
         FILE_UNIX_BASIC_INFO *presp_data;
         __u32 posix_flags = 0;
-        struct cifs_sb_info *cifs_sb = CIFS_SB(mnt->mnt_sb);
+        struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
         struct cifs_fattr fattr;
 
         cFYI(1, "posix open %s", full_path);
@@ -241,7 +242,7 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
 
         /* get new inode and set it up */
         if (*pinode == NULL) {
-                *pinode = cifs_iget(mnt->mnt_sb, &fattr);
+                *pinode = cifs_iget(sb, &fattr);
                 if (!*pinode) {
                         rc = -ENOMEM;
                         goto posix_open_ret;
@@ -250,7 +251,8 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
                 cifs_fattr_to_inode(*pinode, &fattr);
         }
 
-        cifs_new_fileinfo(*pinode, *pnetfid, NULL, mnt, oflags);
+        if (mnt)
+                cifs_new_fileinfo(*pinode, *pnetfid, NULL, mnt, oflags);
 
 posix_open_ret:
         kfree(presp_data);
@@ -314,13 +316,14 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
         if (nd && (nd->flags & LOOKUP_OPEN))
                 oflags = nd->intent.open.flags;
         else
-                oflags = FMODE_READ;
+                oflags = FMODE_READ | SMB_O_CREAT;
 
         if (tcon->unix_ext && (tcon->ses->capabilities & CAP_UNIX) &&
             (CIFS_UNIX_POSIX_PATH_OPS_CAP &
                         le64_to_cpu(tcon->fsUnixInfo.Capability))) {
-                rc = cifs_posix_open(full_path, &newinode, nd->path.mnt,
-                                     mode, oflags, &oplock, &fileHandle, xid);
+                rc = cifs_posix_open(full_path, &newinode,
+                        nd ? nd->path.mnt : NULL,
+                        inode->i_sb, mode, oflags, &oplock, &fileHandle, xid);
                 /* EIO could indicate that (posix open) operation is not
                    supported, despite what server claimed in capability
                    negotation.  EREMOTE indicates DFS junction, which is not
@@ -677,6 +680,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
                      (nd->flags & LOOKUP_OPEN) && !pTcon->broken_posix_open &&
                      (nd->intent.open.flags & O_CREAT)) {
                         rc = cifs_posix_open(full_path, &newInode, nd->path.mnt,
+                                        parent_dir_inode->i_sb,
                                         nd->intent.open.create_mode,
                                         nd->intent.open.flags, &oplock,
                                         &fileHandle, xid);