On Tue, Nov 16, 2010 at 04:20:43PM +0000, Pádraig Brady wrote: > On 15/11/10 17:05, Josef Bacik wrote: > > Ext4 doesn't have the ability to punch holes yet, so make sure we return > > EOPNOTSUPP if we try to use hole punching through fallocate. This support > > can > > be added later. Thanks, > > > > Signed-off-by: Josef Bacik <jo...@redhat.com> > > --- > > fs/ext4/extents.c | 4 ++++ > > 1 files changed, 4 insertions(+), 0 deletions(-) > > > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > > index 0554c48..35bca73 100644 > > --- a/fs/ext4/extents.c > > +++ b/fs/ext4/extents.c > > @@ -3622,6 +3622,10 @@ long ext4_fallocate(struct inode *inode, int mode, > > loff_t offset, loff_t len) > > struct ext4_map_blocks map; > > unsigned int credits, blkbits = inode->i_blkbits; > > > > + /* We only support the FALLOC_FL_KEEP_SIZE mode */ > > + if (mode && (mode != FALLOC_FL_KEEP_SIZE)) > > + return -EOPNOTSUPP; > > + > > /* > > * currently supporting (pre)allocate mode for extent-based > > * files _only_ > > So for older versions of ext4 or other filesystems, how do we know > that fallocate(...,FALLOC_FL_PUNCH_HOLE) is not supported. > I.E. how do we detect at runtime that the call succeeded > and didn't just do a normal fallocate()? >
Older kernels won't accept FALLOC_FL_PUNCH_HOLE, so you'll get an error. Thanks, Josef -- 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
