From 1484081f6113cd33ad538a4a50f332754dbcc873 Mon Sep 17 00:00:00 2001 From: David Disseldorp Date: Thu, 6 Feb 2014 15:29:18 +0100 Subject: [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 Signed-off-by: David Sterba Signed-off-by: Chris Mason --- ioctl.h | 1 + 1 file changed, 1 insertion(+) diff --git a/ioctl.h b/ioctl.h index 2cf9c73e..7f7e1d67 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;