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

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

bfs_fill_super() returns any error incurred when getting the root inode
instead of EINVAL.

[kamalesh@linux.vnet.ibm.com: build fix]
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/bfs/bfs.h

@@ -44,6 +44,8 @@ static inline struct bfs_inode_info *BFS_I(struct inode *inode)
 #define printf(format, args...) \
 	printk(KERN_ERR "BFS-fs: %s(): " format, __FUNCTION__, ## args)
 
+/* inode.c */
+extern struct inode *bfs_iget(struct super_block *sb, unsigned long ino);
 
 /* file.c */
 extern const struct inode_operations bfs_file_inops;

fs/bfs/dir.c

@@ -148,10 +148,10 @@ static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
 	if (bh) {
 		unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
 		brelse(bh);
-		inode = iget(dir->i_sb, ino);
-		if (!inode) {
+		inode = bfs_iget(dir->i_sb, ino);
+		if (IS_ERR(inode)) {
 			unlock_kernel();
-			return ERR_PTR(-EACCES);
+			return ERR_CAST(inode);
 		}
 	}
 	unlock_kernel();

fs/bfs/inode.c

@@ -32,17 +32,22 @@ MODULE_LICENSE("GPL");
 
 void dump_imap(const char *prefix, struct super_block *s);
 
-static void bfs_read_inode(struct inode *inode)
+struct inode *bfs_iget(struct super_block *sb, unsigned long ino)
 {
-	unsigned long ino = inode->i_ino;
 	struct bfs_inode *di;
+	struct inode *inode;
 	struct buffer_head *bh;
 	int block, off;
 
+	inode = iget_locked(sb, ino);
+	if (IS_ERR(inode))
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+
 	if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(inode->i_sb)->si_lasti)) {
 		printf("Bad inode number %s:%08lx\n", inode->i_sb->s_id, ino);
-		make_bad_inode(inode);
-		return;
+		goto error;
 	}
 
 	block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
@@ -50,8 +55,7 @@ static void bfs_read_inode(struct inode *inode)
 	if (!bh) {
 		printf("Unable to read inode %s:%08lx\n", inode->i_sb->s_id,
 									ino);
-		make_bad_inode(inode);
-		return;
+		goto error;
 	}
 
 	off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
@@ -85,6 +89,12 @@ static void bfs_read_inode(struct inode *inode)
 	inode->i_ctime.tv_nsec = 0;
 
 	brelse(bh);
+	unlock_new_inode(inode);
+	return inode;
+
+error:
+	iget_failed(inode);
+	return ERR_PTR(-EIO);
 }
 
 static int bfs_write_inode(struct inode *inode, int unused)
@@ -276,7 +286,6 @@ static void destroy_inodecache(void)
 static const struct super_operations bfs_sops = {
 	.alloc_inode	= bfs_alloc_inode,
 	.destroy_inode	= bfs_destroy_inode,
-	.read_inode	= bfs_read_inode,
 	.write_inode	= bfs_write_inode,
 	.delete_inode	= bfs_delete_inode,
 	.put_super	= bfs_put_super,
@@ -312,6 +321,7 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 	struct inode *inode;
 	unsigned i, imap_len;
 	struct bfs_sb_info *info;
+	long ret = -EINVAL;
 
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (!info)
@@ -346,14 +356,16 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 		set_bit(i, info->si_imap);
 
 	s->s_op = &bfs_sops;
-	inode = iget(s, BFS_ROOT_INO);
-	if (!inode) {
+	inode = bfs_iget(s, BFS_ROOT_INO);
+	if (IS_ERR(inode)) {
+		ret = PTR_ERR(inode);
 		kfree(info->si_imap);
 		goto out;
 	}
 	s->s_root = d_alloc_root(inode);
 	if (!s->s_root) {
 		iput(inode);
+		ret = -ENOMEM;
 		kfree(info->si_imap);
 		goto out;
 	}
@@ -404,7 +416,7 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 	brelse(bh);
 	kfree(info);
 	s->s_fs_info = NULL;
-	return -EINVAL;
+	return ret;
 }
 
 static int bfs_get_sb(struct file_system_type *fs_type,