On Mon, Jun 27, 2022 at 11:37:31AM +1000, Dave Chinner wrote: > On Sun, Jun 26, 2022 at 03:04:04PM -0700, Darrick J. Wong wrote: > > From: Darrick J. Wong <djwong@xxxxxxxxxx> > > > > On a system with a realtime volume and a 28k realtime extent, > > generic/491 fails because the test opens a file on a frozen filesystem > > and closing it causes xfs_release -> xfs_can_free_eofblocks to > > mistakenly think that the the blocks of the realtime extent beyond EOF > > are posteof blocks to be freed. Realtime extents cannot be partially > > unmapped, so this is pointless. Worse yet, this triggers posteof > > cleanup, which stalls on a transaction allocation, which is why the test > > fails. > > > > Teach the predicate to account for realtime extents properly. > > > > Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx> > > --- > > fs/xfs/xfs_bmap_util.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c > > index 52be58372c63..85e1a26c92e8 100644 > > --- a/fs/xfs/xfs_bmap_util.c > > +++ b/fs/xfs/xfs_bmap_util.c > > @@ -686,6 +686,8 @@ xfs_can_free_eofblocks( > > * forever. > > */ > > end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_ISIZE(ip)); > > + if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1) > > + end_fsb = roundup_64(end_fsb, mp->m_sb.sb_rextsize); > > last_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes); > > if (last_fsb <= end_fsb) > > return false; > > Ok, that works. > > However, I was looking at xfs_can_free_eofblocks() w.r.t. freeze a > couple of days ago and wondering why there isn't a freeze/RO state > check in xfs_can_free_eofblocks(). Shouldn't we have one here so > that we never try to run xfs_free_eofblocks() on RO/frozen > filesystems regardless of unexpected state/alignment issues? I asked myself that question too. I found three callers of this predicate: 1. fallocate, which should have obtained freeze protection 2. inodegc, which should never be running when we get to the innermost freeze protection level 3. xfs_release, which doesn't take freeze protection at all. Either it needs to take freeze protection so that xfs_free_eofblocks can't get stuck in xfs_trans_alloc, or we'd need to modify xfs_trans_alloc to sb_start_intwrite_trylock I don't really want to try to add (3) as part of a fix for 5.19, but I would like to get these fixes merged so I can concentrate on finding and fixing the file corruption problems that are still present in -rc4. If we want to engineer a freeze/ro state check later, we can do that too. So, can we move ahead with this fix? --D > Cheers, > > Dave. > > > -- > Dave Chinner > david@xxxxxxxxxxxxx
