>> It's safe and easy to do so, provided the ranges don't overlap.
>>
>> Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
>> ---
>> fs/btrfs/ioctl.c | 23 ++++++++++++++++-------
>> 1 files changed, 16 insertions(+), 7 deletions(-)
>>
>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>> index 0b06a5c..8fcd671 100644
>> --- a/fs/btrfs/ioctl.c
>> +++ b/fs/btrfs/ioctl.c
>> @@ -2223,8 +2223,6 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
>> * decompress into destination's address_space (the file offset
>> * may change, so source mapping won't do), then recompress (or
>> * otherwise reinsert) a subrange.
>> - * - allow ranges within the same file to be cloned (provided
>> - * they don't overlap)?
>> */
>>
>> /* the destination must be opened for writing */
>> @@ -2247,8 +2245,6 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
>> src = src_file->f_dentry->d_inode;
>>
>> ret = -EINVAL;
>> - if (src == inode)
>> - goto out_fput;
>>
>> /* the src must be open for reading */
>> if (!(src_file->f_mode & FMODE_READ))
>> @@ -2282,9 +2278,11 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
>> if (inode < src) {
>> mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
>> mutex_lock_nested(&src->i_mutex, I_MUTEX_CHILD);
>> - } else {
>> + } else if (inode > src) {
>> mutex_lock_nested(&src->i_mutex, I_MUTEX_PARENT);
>> mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
>> + } else {
>> + mutex_lock(&inode->i_mutex);
>> }
>>
>> /* determine range to clone */
>> @@ -2302,6 +2300,13 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
>> !IS_ALIGNED(destoff, bs))
>> goto out_unlock;
>>
>> + /*
>> + * allow ranges within the same file to be cloned only if
>> + * they don't overlap
>> + */
>> + if (src == inode && !(off + len <= destoff || destoff + len <= off))
> ^^^^^^^^^^^^
> ... this check isn't sufficient. Two different inodes can reference the
> same data extent and we must prevent overlap cloning there as well.
>
Could you be more elaborate on this? I don't know what's the problem
you're refering to.
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
