| Message ID | e8bfbbec-4cb9-0267-08eb-03580e2aedc6@redhat.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | xfs: preserve inode versioning across remounts | expand |
On Tue, Jul 14, 2020 at 03:11:34PM -0700, Eric Sandeen wrote: > The MS_I_VERSION mount flag is exposed via the VFS, as documented > in the mount manpages etc; see the iversion and noiversion mount > options in mount(8). > > As a result, mount -o remount looks for this option in /proc/mounts > and will only send the I_VERSION flag back in during remount it it > is present. Since it's not there, a remount will /remove/ the > I_VERSION flag at the vfs level, and iversion functionality is lost. > > xfs v5 superblocks intend to always have i_version enabled; it is > set as a default at mount time, but is lost during remount for the > reasons above. > > The generic fix would be to expose this documented option in > /proc/mounts, but since that was rejected, fix it up again in the > xfs remount path instead, so that at least xfs won't suffer from > this misbehavior. > > Signed-off-by: Eric Sandeen <sandeen@redhat.com> > -- > > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c > index 379cbff438bc..9239985571af 100644 > --- a/fs/xfs/xfs_super.c > +++ b/fs/xfs/xfs_super.c > @@ -1714,6 +1714,10 @@ xfs_fc_reconfigure( > int flags = fc->sb_flags; > int error; > > + /* version 5 superblocks always support version counters. */ > + if (XFS_SB_VERSION_NUM(&mp->m_sb) == XFS_SB_VERSION_5) > + fc->sb_flags |= SB_I_VERSION; > + > error = xfs_fc_validate_params(new_mp); > if (error) > return error; Looks fine. Reviewed-by: Dave Chinner <dchinner@redhat.com>
On Tue, Jul 14, 2020 at 03:11:34PM -0700, Eric Sandeen wrote: > The MS_I_VERSION mount flag is exposed via the VFS, as documented > in the mount manpages etc; see the iversion and noiversion mount > options in mount(8). > > As a result, mount -o remount looks for this option in /proc/mounts > and will only send the I_VERSION flag back in during remount it it > is present. Since it's not there, a remount will /remove/ the > I_VERSION flag at the vfs level, and iversion functionality is lost. > > xfs v5 superblocks intend to always have i_version enabled; it is > set as a default at mount time, but is lost during remount for the > reasons above. Looks good, this fixes the new mount API conversion, as the old code automatically added it. Maybe this wants a Fixes tag. Reviewed-by: Christoph Hellwig <hch@lst.de>
On 7/15/20 11:09 AM, Christoph Hellwig wrote: > On Tue, Jul 14, 2020 at 03:11:34PM -0700, Eric Sandeen wrote: >> The MS_I_VERSION mount flag is exposed via the VFS, as documented >> in the mount manpages etc; see the iversion and noiversion mount >> options in mount(8). >> >> As a result, mount -o remount looks for this option in /proc/mounts >> and will only send the I_VERSION flag back in during remount it it >> is present. Since it's not there, a remount will /remove/ the >> I_VERSION flag at the vfs level, and iversion functionality is lost. >> >> xfs v5 superblocks intend to always have i_version enabled; it is >> set as a default at mount time, but is lost during remount for the >> reasons above. > > Looks good, this fixes the new mount API conversion, as the old code > automatically added it. Maybe this wants a Fixes tag. > > Reviewed-by: Christoph Hellwig <hch@lst.de> AFAICT (and from testing) this behavior predates the mount API conversion. Thanks, -Eric
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 379cbff438bc..9239985571af 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -1714,6 +1714,10 @@ xfs_fc_reconfigure( int flags = fc->sb_flags; int error; + /* version 5 superblocks always support version counters. */ + if (XFS_SB_VERSION_NUM(&mp->m_sb) == XFS_SB_VERSION_5) + fc->sb_flags |= SB_I_VERSION; + error = xfs_fc_validate_params(new_mp); if (error) return error;
The MS_I_VERSION mount flag is exposed via the VFS, as documented in the mount manpages etc; see the iversion and noiversion mount options in mount(8). As a result, mount -o remount looks for this option in /proc/mounts and will only send the I_VERSION flag back in during remount it it is present. Since it's not there, a remount will /remove/ the I_VERSION flag at the vfs level, and iversion functionality is lost. xfs v5 superblocks intend to always have i_version enabled; it is set as a default at mount time, but is lost during remount for the reasons above. The generic fix would be to expose this documented option in /proc/mounts, but since that was rejected, fix it up again in the xfs remount path instead, so that at least xfs won't suffer from this misbehavior. Signed-off-by: Eric Sandeen <sandeen@redhat.com> --