Hi Darrick, On 10/18/2016 03:54 AM, Darrick J. Wong wrote: > Add a blurb to the fallocate manpage explaining that the fallocate > command with the UNSHARE mode flag may use CoW to unshare blocks to > guarantee that a disk write won't fail with ENOSPC.
Thanks! Applied. Cheers, Michael > > Signed-off-by: Darrick J. Wong <darrick.w...@oracle.com> > --- > man2/fallocate.2 | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > > diff --git a/man2/fallocate.2 b/man2/fallocate.2 > index 54d6340..3ed1460 100644 > --- a/man2/fallocate.2 > +++ b/man2/fallocate.2 > @@ -79,6 +79,16 @@ but the file size will not be changed even if > is greater than the file size. > Preallocating zeroed blocks beyond the end of the file in this manner > is useful for optimizing append workloads. > + > +If the > +.B FALLOC_FL_UNSHARE > +flag is specified in > +.IR mode , > +shared file data extents will be made private to the file to guarantee > +that a subsequent write will not fail due to lack of space. > +Typically, this will be done by performing a copy-on-write operation on > +all shared data in the file. > +This flag may not be supported by all filesystems. > .PP > Because allocation is done in block size chunks, > .BR fallocate () > > -- 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-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html