btrfs: tree_search, copy_to_sk: return EOVERFLOW for too small buffer
In copy_to_sk, if an item is too large for the given buffer, it now returns -EOVERFLOW instead of copying a search_header with len = 0. For backward compatibility for the first item it still copies such a header to the buffer, but not any other following items, which could have fitted. tree_search changes -EOVERFLOW back to 0 to behave similiar to the way it behaved before this patch. Signed-off-by: Gerhard Heift <Gerhard@Heift.Name> Signed-off-by: Chris Mason <clm@fb.com> Acked-by: David Sterba <dsterba@suse.cz>
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1254444288
Коммит
8f5f6178f3
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@ -1990,8 +1990,20 @@ static noinline int copy_to_sk(struct btrfs_root *root,
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if (!key_in_sk(key, sk))
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continue;
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if (sizeof(sh) + item_len > buf_size)
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if (sizeof(sh) + item_len > buf_size) {
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if (*num_found) {
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ret = 1;
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goto out;
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}
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/*
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* return one empty item back for v1, which does not
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* handle -EOVERFLOW
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*/
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item_len = 0;
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ret = -EOVERFLOW;
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}
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if (sizeof(sh) + item_len + *sk_offset > buf_size) {
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ret = 1;
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@ -2017,6 +2029,9 @@ static noinline int copy_to_sk(struct btrfs_root *root,
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}
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(*num_found)++;
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if (ret) /* -EOVERFLOW from above */
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goto out;
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if (*num_found >= sk->nr_items) {
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ret = 1;
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goto out;
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@ -2095,7 +2110,8 @@ static noinline int search_ioctl(struct inode *inode,
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break;
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}
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ret = 0;
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if (ret > 0)
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ret = 0;
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err:
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sk->nr_items = num_found;
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btrfs_free_path(path);
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@ -2118,6 +2134,14 @@ static noinline int btrfs_ioctl_tree_search(struct file *file,
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inode = file_inode(file);
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ret = search_ioctl(inode, &args->key, sizeof(args->buf), args->buf);
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/*
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* In the origin implementation an overflow is handled by returning a
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* search header with a len of zero, so reset ret.
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*/
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if (ret == -EOVERFLOW)
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ret = 0;
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if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
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ret = -EFAULT;
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kfree(args);
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