btrfs: tree_search, search_ioctl: direct copy to userspace
By copying each found item seperatly to userspace, we do not need extra buffer in the kernel. 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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550ac1d85e
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@ -1958,7 +1958,7 @@ static noinline int copy_to_sk(struct btrfs_root *root,
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struct btrfs_key *key,
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struct btrfs_key *key,
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struct btrfs_ioctl_search_key *sk,
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struct btrfs_ioctl_search_key *sk,
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size_t *buf_size,
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size_t *buf_size,
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char *buf,
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char __user *ubuf,
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unsigned long *sk_offset,
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unsigned long *sk_offset,
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int *num_found)
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int *num_found)
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{
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{
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@ -2018,14 +2018,22 @@ static noinline int copy_to_sk(struct btrfs_root *root,
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sh.transid = found_transid;
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sh.transid = found_transid;
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/* copy search result header */
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/* copy search result header */
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memcpy(buf + *sk_offset, &sh, sizeof(sh));
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if (copy_to_user(ubuf + *sk_offset, &sh, sizeof(sh))) {
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ret = -EFAULT;
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goto out;
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}
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*sk_offset += sizeof(sh);
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*sk_offset += sizeof(sh);
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if (item_len) {
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if (item_len) {
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char *p = buf + *sk_offset;
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char __user *up = ubuf + *sk_offset;
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/* copy the item */
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/* copy the item */
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read_extent_buffer(leaf, p,
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if (read_extent_buffer_to_user(leaf, up,
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item_off, item_len);
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item_off, item_len)) {
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ret = -EFAULT;
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goto out;
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}
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*sk_offset += item_len;
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*sk_offset += item_len;
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}
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}
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(*num_found)++;
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(*num_found)++;
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@ -2052,13 +2060,22 @@ advance_key:
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} else
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} else
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ret = 1;
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ret = 1;
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out:
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out:
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/*
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* 0: all items from this leaf copied, continue with next
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* 1: * more items can be copied, but unused buffer is too small
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* * all items were found
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* Either way, it will stops the loop which iterates to the next
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* leaf
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* -EOVERFLOW: item was to large for buffer
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* -EFAULT: could not copy extent buffer back to userspace
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*/
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return ret;
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return ret;
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}
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}
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static noinline int search_ioctl(struct inode *inode,
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static noinline int search_ioctl(struct inode *inode,
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struct btrfs_ioctl_search_key *sk,
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struct btrfs_ioctl_search_key *sk,
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size_t *buf_size,
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size_t *buf_size,
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char *buf)
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char __user *ubuf)
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{
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{
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struct btrfs_root *root;
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struct btrfs_root *root;
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struct btrfs_key key;
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struct btrfs_key key;
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@ -2106,7 +2123,7 @@ static noinline int search_ioctl(struct inode *inode,
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ret = 0;
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ret = 0;
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goto err;
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goto err;
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}
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}
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ret = copy_to_sk(root, path, &key, sk, buf_size, buf,
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ret = copy_to_sk(root, path, &key, sk, buf_size, ubuf,
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&sk_offset, &num_found);
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&sk_offset, &num_found);
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btrfs_release_path(path);
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btrfs_release_path(path);
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if (ret)
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if (ret)
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@ -2124,7 +2141,8 @@ err:
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static noinline int btrfs_ioctl_tree_search(struct file *file,
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static noinline int btrfs_ioctl_tree_search(struct file *file,
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void __user *argp)
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void __user *argp)
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{
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{
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struct btrfs_ioctl_search_args *args;
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struct btrfs_ioctl_search_args __user *uargs;
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struct btrfs_ioctl_search_key sk;
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struct inode *inode;
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struct inode *inode;
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int ret;
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int ret;
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size_t buf_size;
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size_t buf_size;
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@ -2132,14 +2150,15 @@ static noinline int btrfs_ioctl_tree_search(struct file *file,
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if (!capable(CAP_SYS_ADMIN))
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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return -EPERM;
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args = memdup_user(argp, sizeof(*args));
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uargs = (struct btrfs_ioctl_search_args __user *)argp;
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if (IS_ERR(args))
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return PTR_ERR(args);
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buf_size = sizeof(args->buf);
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if (copy_from_user(&sk, &uargs->key, sizeof(sk)))
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return -EFAULT;
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buf_size = sizeof(uargs->buf);
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inode = file_inode(file);
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inode = file_inode(file);
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ret = search_ioctl(inode, &args->key, &buf_size, args->buf);
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ret = search_ioctl(inode, &sk, &buf_size, uargs->buf);
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/*
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/*
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* In the origin implementation an overflow is handled by returning a
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* In the origin implementation an overflow is handled by returning a
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@ -2148,9 +2167,8 @@ static noinline int btrfs_ioctl_tree_search(struct file *file,
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if (ret == -EOVERFLOW)
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if (ret == -EOVERFLOW)
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ret = 0;
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ret = 0;
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if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
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if (ret == 0 && copy_to_user(&uargs->key, &sk, sizeof(sk)))
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ret = -EFAULT;
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ret = -EFAULT;
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kfree(args);
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return ret;
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return ret;
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}
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}
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