David Disseldorp
2014-Feb-06 14:29 UTC
[PATCH] ioctl: add note regarding CLONE_RANGE(len=0) behaviour
A BTRFS_IOC_CLONE_RANGE request with a src_length value of zero has the effect of cloning all data from src_offset through to end-of-file. Document this behaviour in the header file for those who (like me) incorrectly assume that no data is cloned in such a case. Signed-off-by: David Disseldorp <ddiss@suse.de> --- ioctl.h | 1 + 1 file changed, 1 insertion(+) diff --git a/ioctl.h b/ioctl.h index a589cd7..f7d435d 100644 --- a/ioctl.h +++ b/ioctl.h @@ -506,6 +506,7 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code) #define BTRFS_IOC_SCAN_DEV _IOW(BTRFS_IOCTL_MAGIC, 4, \ struct btrfs_ioctl_vol_args) +/* With a @src_length of zero, the range from @src_offset->EOF is cloned! */ struct btrfs_ioctl_clone_range_args { __s64 src_fd; __u64 src_offset, src_length; -- 1.8.4.5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html