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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>
This commit is contained in:
Gerhard Heift 2014-01-30 16:24:02 +01:00 committed by Chris Mason
parent 550ac1d85e
commit ba346b357d
1 changed files with 33 additions and 15 deletions
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48
fs/btrfs/ioctl.c
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@ -1958,7 +1958,7 @@ static noinline int copy_to_sk(struct btrfs_root *root,
struct btrfs_key *key,
struct btrfs_ioctl_search_key *sk,
size_t *buf_size,
char *buf,
char __user *ubuf,
unsigned long *sk_offset,
int *num_found)
{
@ -2018,14 +2018,22 @@ static noinline int copy_to_sk(struct btrfs_root *root,
sh.transid = found_transid;
/* copy search result header */
memcpy(buf + *sk_offset, &sh, sizeof(sh));
if (copy_to_user(ubuf + *sk_offset, &sh, sizeof(sh))) {
ret = -EFAULT;
goto out;
}
*sk_offset += sizeof(sh);
if (item_len) {
char *p = buf + *sk_offset;
char __user *up = ubuf + *sk_offset;
/* copy the item */
read_extent_buffer(leaf, p,
item_off, item_len);
if (read_extent_buffer_to_user(leaf, up,
item_off, item_len)) {
ret = -EFAULT;
goto out;
}
*sk_offset += item_len;
}
(*num_found)++;
@ -2052,13 +2060,22 @@ advance_key:
} else
ret = 1;
out:
/*
* 0: all items from this leaf copied, continue with next
* 1: * more items can be copied, but unused buffer is too small
* * all items were found
* Either way, it will stops the loop which iterates to the next
* leaf
* -EOVERFLOW: item was to large for buffer
* -EFAULT: could not copy extent buffer back to userspace
*/
return ret;
}
static noinline int search_ioctl(struct inode *inode,
struct btrfs_ioctl_search_key *sk,
size_t *buf_size,
char *buf)
char __user *ubuf)
{
struct btrfs_root *root;
struct btrfs_key key;
@ -2106,7 +2123,7 @@ static noinline int search_ioctl(struct inode *inode,
ret = 0;
goto err;
}
ret = copy_to_sk(root, path, &key, sk, buf_size, buf,
ret = copy_to_sk(root, path, &key, sk, buf_size, ubuf,
&sk_offset, &num_found);
btrfs_release_path(path);
if (ret)
@ -2124,7 +2141,8 @@ err:
static noinline int btrfs_ioctl_tree_search(struct file *file,
void __user *argp)
{
struct btrfs_ioctl_search_args *args;
struct btrfs_ioctl_search_args __user *uargs;
struct btrfs_ioctl_search_key sk;
struct inode *inode;
int ret;
size_t buf_size;
@ -2132,14 +2150,15 @@ static noinline int btrfs_ioctl_tree_search(struct file *file,
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
args = memdup_user(argp, sizeof(*args));
if (IS_ERR(args))
return PTR_ERR(args);
uargs = (struct btrfs_ioctl_search_args __user *)argp;
buf_size = sizeof(args->buf);
if (copy_from_user(&sk, &uargs->key, sizeof(sk)))
return -EFAULT;
buf_size = sizeof(uargs->buf);
inode = file_inode(file);
ret = search_ioctl(inode, &args->key, &buf_size, args->buf);
ret = search_ioctl(inode, &sk, &buf_size, uargs->buf);
/*
* In the origin implementation an overflow is handled by returning a
@ -2148,9 +2167,8 @@ static noinline int btrfs_ioctl_tree_search(struct file *file,
if (ret == -EOVERFLOW)
ret = 0;
if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
if (ret == 0 && copy_to_user(&uargs->key, &sk, sizeof(sk)))
ret = -EFAULT;
kfree(args);
return ret;
}