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>

3 files changed, 24 insertions, 7 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index e9f4ec701092..fcc434227691 100644
--- a/fs/cifs/cifsfs.c
+++ b/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,
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 195b14de5567..68978306c3ca 100644
--- a/fs/cifs/cifsfs.h
+++ b/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 *,
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 47f2621001e4..b1a4a65eaa08 100644
--- a/fs/cifs/inode.c
+++ b/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)