lkml.org 
[lkml]   [2010]   [Nov]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [PATCH 4/6] Ext4: fail if we try to use hole punch
    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 <josef@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-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2010-11-16 17:37    [W:0.022 / U:32.488 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site