On Fri, Dec 13, 2019 at 08:13:49AM -0800, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > > Alex Lyakas reported[1] that mounting an xfs filesystem with new sunit > and swidth values could cause xfs_repair to fail loudly. The problem > here is that repair calculates the where mkfs should have allocated the > root inode, based on the superblock geometry. The allocation decisions > depend on sunit, which means that we really can't go updating sunit if > it would lead to a subsequent repair failure on an otherwise correct > filesystem. > > Port from xfs_repair some code that computes the location of the root > inode and teach mount to skip the ondisk update if it would cause > problems for repair. Along the way we'll update the documentation, > provide a function for computing the minimum AGFL size instead of > open-coding it, and cut down some indenting in the mount code. > > Note that we allow the mount to proceed (and new allocations will > reflect this new geometry) because we've never screened this kind of > thing before. We'll have to wait for a new future incompat feature to > enforce correct behavior, alas. > > Note that the geometry reporting always uses the superblock values, not > the incore ones, so that is what xfs_info and xfs_growfs will report. > > [1] https://lore.kernel.org/linux-xfs/20191125130744.GA44777@bfoster/T/#m00f9594b511e076e2fcdd489d78bc30216d72a7d > > Reported-by: Alex Lyakas <alex@xxxxxxxxxx> > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > --- > v2: refactor the agfl length calculations, clarify the fsgeometry ioctl > behavior, fix a bunch of the comments and make it clearer how we compute > the rootino location > --- > fs/xfs/libxfs/xfs_alloc.c | 18 ++++++--- > fs/xfs/libxfs/xfs_ialloc.c | 70 ++++++++++++++++++++++++++++++++++ > fs/xfs/libxfs/xfs_ialloc.h | 1 > fs/xfs/xfs_mount.c | 90 ++++++++++++++++++++++++++++++-------------- > fs/xfs/xfs_trace.h | 21 ++++++++++ > 5 files changed, 166 insertions(+), 34 deletions(-) > ... > diff --git a/fs/xfs/libxfs/xfs_ialloc.h b/fs/xfs/libxfs/xfs_ialloc.h > index 323592d563d5..72b3468b97b1 100644 > --- a/fs/xfs/libxfs/xfs_ialloc.h > +++ b/fs/xfs/libxfs/xfs_ialloc.h ... > @@ -398,28 +431,26 @@ xfs_update_alignment(xfs_mount_t *mp) > } > } > > - /* > - * Update superblock with new values > - * and log changes > - */ > - if (xfs_sb_version_hasdalign(sbp)) { > - if (sbp->sb_unit != mp->m_dalign) { > - sbp->sb_unit = mp->m_dalign; > - mp->m_update_sb = true; > - } > - if (sbp->sb_width != mp->m_swidth) { > - sbp->sb_width = mp->m_swidth; > - mp->m_update_sb = true; > - } > - } else { > + /* Update superblock with new values and log changes. */ > + if (!xfs_sb_version_hasdalign(sbp)) { > xfs_warn(mp, > "cannot change alignment: superblock does not support data alignment"); > return -EINVAL; > } > + > + if (sbp->sb_unit == mp->m_dalign && > + sbp->sb_width == mp->m_swidth) > + return 0; > + > + xfs_check_new_dalign(mp, mp->m_dalign); > + > + sbp->sb_unit = mp->m_dalign; > + sbp->sb_width = mp->m_swidth; > + mp->m_update_sb = true; Isn't this supposed to conditionally update the superblock based on the rootino calculation? Brian > } else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN && > xfs_sb_version_hasdalign(&mp->m_sb)) { > - mp->m_dalign = sbp->sb_unit; > - mp->m_swidth = sbp->sb_width; > + mp->m_dalign = sbp->sb_unit; > + mp->m_swidth = sbp->sb_width; > } > > return 0; > @@ -647,16 +678,6 @@ xfs_mountfs( > mp->m_update_sb = true; > } > > - /* > - * Check if sb_agblocks is aligned at stripe boundary > - * If sb_agblocks is NOT aligned turn off m_dalign since > - * allocator alignment is within an ag, therefore ag has > - * to be aligned at stripe boundary. > - */ > - error = xfs_update_alignment(mp); > - if (error) > - goto out; > - > xfs_alloc_compute_maxlevels(mp); > xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK); > xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK); > @@ -664,6 +685,17 @@ xfs_mountfs( > xfs_rmapbt_compute_maxlevels(mp); > xfs_refcountbt_compute_maxlevels(mp); > > + /* > + * Check if sb_agblocks is aligned at stripe boundary. If sb_agblocks > + * is NOT aligned turn off m_dalign since allocator alignment is within > + * an ag, therefore ag has to be aligned at stripe boundary. Note that > + * we must compute the free space and rmap btree geometry before doing > + * this. > + */ > + error = xfs_update_alignment(mp); > + if (error) > + goto out; > + > /* enable fail_at_unmount as default */ > mp->m_fail_unmount = true; > > diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h > index c13bb3655e48..a86be7f807ee 100644 > --- a/fs/xfs/xfs_trace.h > +++ b/fs/xfs/xfs_trace.h > @@ -3573,6 +3573,27 @@ DEFINE_KMEM_EVENT(kmem_alloc_large); > DEFINE_KMEM_EVENT(kmem_realloc); > DEFINE_KMEM_EVENT(kmem_zone_alloc); > > +TRACE_EVENT(xfs_check_new_dalign, > + TP_PROTO(struct xfs_mount *mp, int new_dalign, xfs_ino_t calc_rootino), > + TP_ARGS(mp, new_dalign, calc_rootino), > + TP_STRUCT__entry( > + __field(dev_t, dev) > + __field(int, new_dalign) > + __field(xfs_ino_t, sb_rootino) > + __field(xfs_ino_t, calc_rootino) > + ), > + TP_fast_assign( > + __entry->dev = mp->m_super->s_dev; > + __entry->new_dalign = new_dalign; > + __entry->sb_rootino = mp->m_sb.sb_rootino; > + __entry->calc_rootino = calc_rootino; > + ), > + TP_printk("dev %d:%d new_dalign %d sb_rootino %llu calc_rootino %llu", > + MAJOR(__entry->dev), MINOR(__entry->dev), > + __entry->new_dalign, __entry->sb_rootino, > + __entry->calc_rootino) > +) > + > #endif /* _TRACE_XFS_H */ > > #undef TRACE_INCLUDE_PATH >
