switch minix to ->evict_inode(), fix write_inode/delete_inode race

We need to wait for completion of possible writeback in progress
before we clear on-disk inode during deletion.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/minix/bitmap.c

@@ -200,13 +200,13 @@ void minix_free_inode(struct inode * inode)
 	ino = inode->i_ino;
 	if (ino < 1 || ino > sbi->s_ninodes) {
 		printk("minix_free_inode: inode 0 or nonexistent inode\n");
-		goto out;
+		return;
 	}
 	bit = ino & ((1<<k) - 1);
 	ino >>= k;
 	if (ino >= sbi->s_imap_blocks) {
 		printk("minix_free_inode: nonexistent imap in superblock\n");
-		goto out;
+		return;
 	}
 
 	minix_clear_inode(inode);	/* clear on-disk copy */
@@ -217,8 +217,6 @@ void minix_free_inode(struct inode * inode)
 		printk("minix_free_inode: bit %lu already cleared\n", bit);
 	spin_unlock(&bitmap_lock);
 	mark_buffer_dirty(bh);
- out:
-	clear_inode(inode);		/* clear in-memory copy */
 }
 
 struct inode *minix_new_inode(const struct inode *dir, int mode, int *error)

fs/minix/inode.c

@@ -24,12 +24,17 @@ static int minix_write_inode(struct inode *inode,
 static int minix_statfs(struct dentry *dentry, struct kstatfs *buf);
 static int minix_remount (struct super_block * sb, int * flags, char * data);
 
-static void minix_delete_inode(struct inode *inode)
+static void minix_evict_inode(struct inode *inode)
 {
 	truncate_inode_pages(&inode->i_data, 0);
-	inode->i_size = 0;
-	minix_truncate(inode);
-	minix_free_inode(inode);
+	if (!inode->i_nlink) {
+		inode->i_size = 0;
+		minix_truncate(inode);
+	}
+	invalidate_inode_buffers(inode);
+	end_writeback(inode);
+	if (!inode->i_nlink)
+		minix_free_inode(inode);
 }
 
 static void minix_put_super(struct super_block *sb)
@@ -96,7 +101,7 @@ static const struct super_operations minix_sops = {
 	.alloc_inode	= minix_alloc_inode,
 	.destroy_inode	= minix_destroy_inode,
 	.write_inode	= minix_write_inode,
-	.delete_inode	= minix_delete_inode,
+	.evict_inode	= minix_evict_inode,
 	.put_super	= minix_put_super,
 	.statfs		= minix_statfs,
 	.remount_fs	= minix_remount,