hpfs: handle allocation failures in hpfs_add_pos()

pr_err() is nice, but we'd better propagate the error
to caller and not proceed to violate the invariants
(namely, "every file with f_pos tied to directory block
should have its address visible in per-inode array").
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/hpfs/dir.c

@@ -44,7 +44,11 @@ static loff_t hpfs_dir_lseek(struct file *filp, loff_t off, int whence)
 		else goto fail;
 		if (pos == 12) goto fail;
 	}
-	hpfs_add_pos(i, &filp->f_pos);
+	if (unlikely(hpfs_add_pos(i, &filp->f_pos) < 0)) {
+		hpfs_unlock(s);
+		inode_unlock(i);
+		return -ENOMEM;
+	}
 ok:
 	filp->f_pos = new_off;
 	hpfs_unlock(s);
@@ -141,8 +145,10 @@ static int hpfs_readdir(struct file *file, struct dir_context *ctx)
 			ctx->pos = 1;
 		}
 		if (ctx->pos == 1) {
+			ret = hpfs_add_pos(inode, &file->f_pos);
+			if (unlikely(ret < 0))
+				goto out;
 			ctx->pos = ((loff_t) hpfs_de_as_down_as_possible(inode->i_sb, hpfs_inode->i_dno) << 4) + 1;
-			hpfs_add_pos(inode, &file->f_pos);
 			file->f_version = inode->i_version;
 		}
 		next_pos = ctx->pos;

fs/hpfs/dnode.c

@@ -21,7 +21,7 @@ static loff_t get_pos(struct dnode *d, struct hpfs_dirent *fde)
 	return ((loff_t)le32_to_cpu(d->self) << 4) | (loff_t)1;
 }
 
-void hpfs_add_pos(struct inode *inode, loff_t *pos)
+int hpfs_add_pos(struct inode *inode, loff_t *pos)
 {
 	struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
 	int i = 0;
@@ -29,11 +29,12 @@ void hpfs_add_pos(struct inode *inode, loff_t *pos)
 
 	if (hpfs_inode->i_rddir_off)
 		for (; hpfs_inode->i_rddir_off[i]; i++)
-			if (hpfs_inode->i_rddir_off[i] == pos) return;
+			if (hpfs_inode->i_rddir_off[i] == pos)
+				return 0;
 	if (!(i&0x0f)) {
 		if (!(ppos = kmalloc((i+0x11) * sizeof(loff_t*), GFP_NOFS))) {
 			pr_err("out of memory for position list\n");
-			return;
+			return -ENOMEM;
 		}
 		if (hpfs_inode->i_rddir_off) {
 			memcpy(ppos, hpfs_inode->i_rddir_off, i * sizeof(loff_t));
@@ -43,6 +44,7 @@ void hpfs_add_pos(struct inode *inode, loff_t *pos)
 	}
 	hpfs_inode->i_rddir_off[i] = pos;
 	hpfs_inode->i_rddir_off[i + 1] = NULL;
+	return 0;
 }
 
 void hpfs_del_pos(struct inode *inode, loff_t *pos)

fs/hpfs/hpfs_fn.h

@@ -242,7 +242,7 @@ extern const struct file_operations hpfs_dir_ops;
 
 /* dnode.c */
 
-void hpfs_add_pos(struct inode *, loff_t *);
+int hpfs_add_pos(struct inode *, loff_t *);
 void hpfs_del_pos(struct inode *, loff_t *);
 struct hpfs_dirent *hpfs_add_de(struct super_block *, struct dnode *,
 				const unsigned char *, unsigned, secno);