On Tue, Oct 02, 2018 at 10:42:01AM -0700, Christoph Hellwig wrote:
> The option to enable unwritten extents was made default in 2003, removed
> from mkfs in 2007, and cannot be disabled in v5. We also rely on it for
> a lot of common functionality, so filesystems without it will run a
> completely untested and buggy code path. Enabling the support also is
> a simple bit flip using xfs_db, so legacy file systems can still be
> brought forward.
Will there be a migration tool in xfsprogs to help administrators roll
their filesystems forward? Generally we don't seem to support enabling
new features on old filesystems (ala ext4) though maybe we should for a
very small and controlled set of porting operations?
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/xfs/libxfs/xfs_bmap.c | 21 ++++++----------
> fs/xfs/libxfs/xfs_format.h | 8 ++----
> fs/xfs/libxfs/xfs_sb.c | 5 ++--
> fs/xfs/scrub/scrub.c | 13 ----------
> fs/xfs/xfs_bmap_util.c | 51 +-------------------------------------
> fs/xfs/xfs_ioctl.c | 8 ------
> 6 files changed, 12 insertions(+), 94 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index a47670332326..da6b768664e3 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -4081,8 +4081,7 @@ xfs_bmapi_allocate(
> * extents to real extents when we're about to write the data.
> */
> if ((!bma->wasdel || (bma->flags & XFS_BMAPI_COWFORK)) &&
> - (bma->flags & XFS_BMAPI_PREALLOC) &&
> - xfs_sb_version_hasextflgbit(&mp->m_sb))
> + (bma->flags & XFS_BMAPI_PREALLOC))
> bma->got.br_state = XFS_EXT_UNWRITTEN;
>
> if (bma->wasdel)
> @@ -5245,8 +5244,7 @@ __xfs_bunmapi(
> * unmapping part of it. But we can't really
> * get rid of part of a realtime extent.
> */
> - if (del.br_state == XFS_EXT_UNWRITTEN ||
> - !xfs_sb_version_hasextflgbit(&mp->m_sb)) {
> + if (del.br_state == XFS_EXT_UNWRITTEN) {
> /*
> * This piece is unwritten, or we're not
> * using unwritten extents. Skip over it.
> @@ -5296,10 +5294,9 @@ __xfs_bunmapi(
> del.br_blockcount -= mod;
> del.br_startoff += mod;
> del.br_startblock += mod;
> - } else if ((del.br_startoff == start &&
> - (del.br_state == XFS_EXT_UNWRITTEN ||
> - tp->t_blk_res == 0)) ||
> - !xfs_sb_version_hasextflgbit(&mp->m_sb)) {
> + } else if (del.br_startoff == start &&
> + (del.br_state == XFS_EXT_UNWRITTEN ||
> + tp->t_blk_res == 0)) {
> /*
> * Can't make it unwritten. There isn't
> * a full extent here so just skip it.
> @@ -6114,11 +6111,7 @@ xfs_bmap_validate_extent(
> XFS_FSB_TO_AGNO(mp, endfsb))
> return __this_address;
> }
> - if (irec->br_state != XFS_EXT_NORM) {
> - if (whichfork != XFS_DATA_FORK)
> - return __this_address;
> - if (!xfs_sb_version_hasextflgbit(&mp->m_sb))
> - return __this_address;
> - }
> + if (irec->br_state != XFS_EXT_NORM && whichfork != XFS_DATA_FORK)
> + return __this_address;
> return NULL;
> }
> diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> index afbe336600e1..9995d5ae380b 100644
> --- a/fs/xfs/libxfs/xfs_format.h
> +++ b/fs/xfs/libxfs/xfs_format.h
> @@ -287,6 +287,8 @@ static inline bool xfs_sb_good_v4_features(struct xfs_sb *sbp)
> {
> if (!(sbp->sb_versionnum & XFS_SB_VERSION_DIRV2BIT))
> return false;
> + if (!(sbp->sb_versionnum & XFS_SB_VERSION_EXTFLGBIT))
> + return false;
The kernel only spits out "XFS(sda): bad version" in dmesg. Maybe it'd
be helpful to steer admins towards whatever they need to do to make
their ancient fs work again?
--D
>
> /* check for unknown features in the fs */
> if ((sbp->sb_versionnum & ~XFS_SB_VERSION_OKBITS) ||
> @@ -357,12 +359,6 @@ static inline bool xfs_sb_version_haslogv2(struct xfs_sb *sbp)
> (sbp->sb_versionnum & XFS_SB_VERSION_LOGV2BIT);
> }
>
> -static inline bool xfs_sb_version_hasextflgbit(struct xfs_sb *sbp)
> -{
> - return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 ||
> - (sbp->sb_versionnum & XFS_SB_VERSION_EXTFLGBIT);
> -}
> -
> static inline bool xfs_sb_version_hassector(struct xfs_sb *sbp)
> {
> return (sbp->sb_versionnum & XFS_SB_VERSION_SECTORBIT);
> diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
> index 081f46e30556..b5a82acd7dfe 100644
> --- a/fs/xfs/libxfs/xfs_sb.c
> +++ b/fs/xfs/libxfs/xfs_sb.c
> @@ -1115,7 +1115,8 @@ xfs_fs_geometry(
>
> geo->version = XFS_FSOP_GEOM_VERSION;
> geo->flags = XFS_FSOP_GEOM_FLAGS_NLINK |
> - XFS_FSOP_GEOM_FLAGS_DIRV2;
> + XFS_FSOP_GEOM_FLAGS_DIRV2 |
> + XFS_FSOP_GEOM_FLAGS_EXTFLG;
> if (xfs_sb_version_hasattr(sbp))
> geo->flags |= XFS_FSOP_GEOM_FLAGS_ATTR;
> if (xfs_sb_version_hasquota(sbp))
> @@ -1124,8 +1125,6 @@ xfs_fs_geometry(
> geo->flags |= XFS_FSOP_GEOM_FLAGS_IALIGN;
> if (xfs_sb_version_hasdalign(sbp))
> geo->flags |= XFS_FSOP_GEOM_FLAGS_DALIGN;
> - if (xfs_sb_version_hasextflgbit(sbp))
> - geo->flags |= XFS_FSOP_GEOM_FLAGS_EXTFLG;
> if (xfs_sb_version_hassector(sbp))
> geo->flags |= XFS_FSOP_GEOM_FLAGS_SECTOR;
> if (xfs_sb_version_hasasciici(sbp))
> diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
> index 4bfae1e61d30..1b2344d00525 100644
> --- a/fs/xfs/scrub/scrub.c
> +++ b/fs/xfs/scrub/scrub.c
> @@ -412,19 +412,6 @@ xchk_validate_inputs(
> goto out;
> }
>
> - error = -EOPNOTSUPP;
> - /*
> - * We won't scrub any filesystem that doesn't have the ability
> - * to record unwritten extents. The option was made default in
> - * 2003, removed from mkfs in 2007, and cannot be disabled in
> - * v5, so if we find a filesystem without this flag it's either
> - * really old or totally unsupported. Avoid it either way.
> - * We also don't support v1-v3 filesystems, which aren't
> - * mountable.
> - */
> - if (!xfs_sb_version_hasextflgbit(&mp->m_sb))
> - goto out;
> -
> /*
> * We only want to repair read-write v5+ filesystems. Defer the check
> * for ops->repair until after our scrub confirms that we need to
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index 6de8d90041ff..416524f6ba69 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -1042,44 +1042,6 @@ xfs_unmap_extent(
> goto out_unlock;
> }
>
> -static int
> -xfs_adjust_extent_unmap_boundaries(
> - struct xfs_inode *ip,
> - xfs_fileoff_t *startoffset_fsb,
> - xfs_fileoff_t *endoffset_fsb)
> -{
> - struct xfs_mount *mp = ip->i_mount;
> - struct xfs_bmbt_irec imap;
> - int nimap, error;
> - xfs_extlen_t mod = 0;
> -
> - nimap = 1;
> - error = xfs_bmapi_read(ip, *startoffset_fsb, 1, &imap, &nimap, 0);
> - if (error)
> - return error;
> -
> - if (nimap && imap.br_startblock != HOLESTARTBLOCK) {
> - ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
> - div_u64_rem(imap.br_startblock, mp->m_sb.sb_rextsize, &mod);
> - if (mod)
> - *startoffset_fsb += mp->m_sb.sb_rextsize - mod;
> - }
> -
> - nimap = 1;
> - error = xfs_bmapi_read(ip, *endoffset_fsb - 1, 1, &imap, &nimap, 0);
> - if (error)
> - return error;
> -
> - if (nimap && imap.br_startblock != HOLESTARTBLOCK) {
> - ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
> - mod++;
> - if (mod && mod != mp->m_sb.sb_rextsize)
> - *endoffset_fsb -= mod;
> - }
> -
> - return 0;
> -}
> -
> static int
> xfs_flush_unmap_range(
> struct xfs_inode *ip,
> @@ -1133,19 +1095,8 @@ xfs_free_file_space(
> endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);
>
> /*
> - * Need to zero the stuff we're not freeing, on disk. If it's a RT file
> - * and we can't use unwritten extents then we actually need to ensure
> - * to zero the whole extent, otherwise we just need to take of block
> - * boundaries, and xfs_bunmapi will handle the rest.
> + * Need to zero the stuff we're not freeing, on disk.
> */
> - if (XFS_IS_REALTIME_INODE(ip) &&
> - !xfs_sb_version_hasextflgbit(&mp->m_sb)) {
> - error = xfs_adjust_extent_unmap_boundaries(ip, &startoffset_fsb,
> - &endoffset_fsb);
> - if (error)
> - return error;
> - }
> -
> if (endoffset_fsb > startoffset_fsb) {
> while (!done) {
> error = xfs_unmap_extent(ip, startoffset_fsb,
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 0ef5ece5634c..6e2c08f30f60 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -604,14 +604,6 @@ xfs_ioc_space(
> uint iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
> int error;
>
> - /*
> - * Only allow the sys admin to reserve space unless
> - * unwritten extents are enabled.
> - */
> - if (!xfs_sb_version_hasextflgbit(&ip->i_mount->m_sb) &&
> - !capable(CAP_SYS_ADMIN))
> - return -EPERM;
> -
> if (inode->i_flags & (S_IMMUTABLE|S_APPEND))
> return -EPERM;
>
> --
> 2.19.0
>
