Hi Darrick, On 10/18/2016 03:54 AM, Darrick J. Wong wrote: > Clarify the behavior of the dedupe ioctl. Thanks! Applied. Cheers, Michael > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > --- > man2/ioctl_ficlonerange.2 | 2 +- > man2/ioctl_fideduperange.2 | 26 ++++++++++++++++++++++---- > 2 files changed, 23 insertions(+), 5 deletions(-) > > > diff --git a/man2/ioctl_ficlonerange.2 b/man2/ioctl_ficlonerange.2 > index ac0738a..0e3ae0e 100644 > --- a/man2/ioctl_ficlonerange.2 > +++ b/man2/ioctl_ficlonerange.2 > @@ -114,7 +114,7 @@ regions in directories. > .TP > .B EOPNOTSUPP > This can appear if the filesystem does not support reflinking either file > -descriptor. > +descriptor, or if either file descriptor refers to special inodes. > .TP > .B EPERM > .IR dest_fd > diff --git a/man2/ioctl_fideduperange.2 b/man2/ioctl_fideduperange.2 > index c52fa2a..2112d10 100644 > --- a/man2/ioctl_fideduperange.2 > +++ b/man2/ioctl_fideduperange.2 > @@ -99,21 +99,39 @@ Each deduplication operation targets > bytes in file descriptor > .IR dest_fd > at offset > -.IR logical_offset ". > +.IR dest_offset ". > The field > .IR reserved > must be zero. > +During the call, > +.IR src_fd > +must be open for reading and > +.IR dest_fd > +must be open for writing. > +For any call to this ioctl, there may not be more than 65,536 > +requests attached; each request may not exceed 16MiB. > +By convention, the storage used by > +.IR src_fd > +is mapped into > +.IR dest_fd > +and the previous contents in > +.IR dest_fd > +are freed. > > Upon successful completion of this ioctl, the number of bytes successfully > deduplicated is returned in > .IR bytes_deduped > and a status code for the deduplication operation is returned in > .IR status ". > - > +If even a single byte in the range does not match, the deduplication > +request will be ignored and > +.IR status > +set to > +.BR FILE_DEDUPE_RANGE_DIFFERS . > The > .IR status > code is set to > -.B 0 > +.B FILE_DEDUPE_RANGE_SAME > for success, a negative error code in case of error, or > .B FILE_DEDUPE_RANGE_DIFFERS > if the data did not match. > @@ -150,7 +168,7 @@ regions in directories. > .TP > .B EOPNOTSUPP > This can appear if the filesystem does not support deduplicating either file > -descriptor. > +descriptor, or if either file descriptor refers to special inodes. > .TP > .B EPERM > .IR dest_fd > > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
