iget: stop CIFS from using iget() and read_inode()

Stop the CIFS filesystem from using iget() and read_inode().  Replace
cifs_read_inode() with cifs_iget(), and call that instead of iget().
cifs_iget() then uses iget_locked() directly and returns a proper error code
instead of an inode in the event of an error.

cifs_read_super() now returns any error incurred when getting the root inode
instead of ENOMEM.

cifs_iget() needs examining.  The comment "can not call macro FreeXid here
since in a void func" is no longer true.
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Steven French <sfrench@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/cifs/cifsfs.c

@@ -147,10 +147,11 @@ cifs_read_super(struct super_block *sb, void *data,
 #endif
 	sb->s_blocksize = CIFS_MAX_MSGSIZE;
 	sb->s_blocksize_bits = 14;	/* default 2**14 = CIFS_MAX_MSGSIZE */
-	inode = iget(sb, ROOT_I);
+	inode = cifs_iget(sb, ROOT_I);
 
-	if (!inode) {
-		rc = -ENOMEM;
+	if (IS_ERR(inode)) {
+		rc = PTR_ERR(inode);
+		inode = NULL;
 		goto out_no_root;
 	}
 
@@ -520,7 +521,6 @@ static int cifs_remount(struct super_block *sb, int *flags, char *data)
 }
 
 static const struct super_operations cifs_super_ops = {
-	.read_inode = cifs_read_inode,
 	.put_super = cifs_put_super,
 	.statfs = cifs_statfs,
 	.alloc_inode = cifs_alloc_inode,

fs/cifs/cifsfs.h

@@ -44,6 +44,7 @@ extern void cifs_read_inode(struct inode *);
 
 /* Functions related to inodes */
 extern const struct inode_operations cifs_dir_inode_ops;
+extern struct inode *cifs_iget(struct super_block *, unsigned long);
 extern int cifs_create(struct inode *, struct dentry *, int,
 		       struct nameidata *);
 extern struct dentry *cifs_lookup(struct inode *, struct dentry *,

fs/cifs/inode.c

@@ -586,10 +586,18 @@ static const struct inode_operations cifs_ipc_inode_ops = {
 };
 
 /* gets root inode */
-void cifs_read_inode(struct inode *inode)
+struct inode *cifs_iget(struct super_block *sb, unsigned long ino)
 {
-	int xid, rc;
+	int xid;
 	struct cifs_sb_info *cifs_sb;
+	struct inode *inode;
+	long rc;
+
+	inode = iget_locked(sb, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
 
 	cifs_sb = CIFS_SB(inode->i_sb);
 	xid = GetXid();
@@ -606,10 +614,18 @@ void cifs_read_inode(struct inode *inode)
 		inode->i_fop = &simple_dir_operations;
 		inode->i_uid = cifs_sb->mnt_uid;
 		inode->i_gid = cifs_sb->mnt_gid;
+		_FreeXid(xid);
+		iget_failed(inode);
+		return ERR_PTR(rc);
 	}
 
-	/* can not call macro FreeXid here since in a void func */
+	unlock_new_inode(inode);
+
+	/* can not call macro FreeXid here since in a void func
+	 * TODO: This is no longer true
+	 */
 	_FreeXid(xid);
+	return inode;
 }
 
 int cifs_unlink(struct inode *inode, struct dentry *direntry)