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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>
This commit is contained in:
Gerhard Heift 2014-01-30 16:23:59 +01:00 committed by Chris Mason
parent 1254444288
commit 8f5f6178f3
1 changed files with 26 additions and 2 deletions
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28
fs/btrfs/ioctl.c
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@ -1990,8 +1990,20 @@ static noinline int copy_to_sk(struct btrfs_root *root,
if (!key_in_sk(key, sk))
continue;
if (sizeof(sh) + item_len > buf_size)
if (sizeof(sh) + item_len > buf_size) {
if (*num_found) {
ret = 1;
goto out;
}
/*
* return one empty item back for v1, which does not
* handle -EOVERFLOW
*/
item_len = 0;
ret = -EOVERFLOW;
}
if (sizeof(sh) + item_len + *sk_offset > buf_size) {
ret = 1;
@ -2017,6 +2029,9 @@ static noinline int copy_to_sk(struct btrfs_root *root,
}
(*num_found)++;
if (ret) /* -EOVERFLOW from above */
goto out;
if (*num_found >= sk->nr_items) {
ret = 1;
goto out;
@ -2095,7 +2110,8 @@ static noinline int search_ioctl(struct inode *inode,
break;
}
ret = 0;
if (ret > 0)
ret = 0;
err:
sk->nr_items = num_found;
btrfs_free_path(path);
@ -2118,6 +2134,14 @@ static noinline int btrfs_ioctl_tree_search(struct file *file,
inode = file_inode(file);
ret = search_ioctl(inode, &args->key, sizeof(args->buf), args->buf);
/*
* In the origin implementation an overflow is handled by returning a
* search header with a len of zero, so reset ret.
*/
if (ret == -EOVERFLOW)
ret = 0;
if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
ret = -EFAULT;
kfree(args);