[RFC PATCH] xfs: always honor OWN_UNKNOWN rmap removal requests

["Darrick J. Wong" <darrick.wong@oracle.com>]

From: Darrick J. Wong <darrick.wong@oracle.com>

Calling xfs_rmap_free with an unknown owner is supposed to remove any
rmaps covering that range regardless of owner.  This is used by the EFI
recovery code to say "we're freeing this, it mustn't be owned by
anything anymore", but for whatever reason xfs_free_ag_extent filters
them out.

Therefore, remove the filter and make xfs_rmap_unmap actually treat it
as a wildcard owner -- free anything that's already there, and if
there's no owner at all then that's fine too.

There are two existing callers of bmap_add_free that take care the rmap
deferred ops themselves and use OWN_UNKNOWN to skip the EFI-based rmap
cleanup; convert these to use OWN_NULL, and ensure that the RUI gets
added to the defer ops ahead of any EFI.

Lastly, now that xfs_free_extent filters out OWN_NULL rmap free requests,
growfs will have to consult directly with the rmap to ensure that there
aren't any rmaps in the grown region.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/libxfs/xfs_alloc.c    |    2 +-
 fs/xfs/libxfs/xfs_bmap.c     |    2 +-
 fs/xfs/libxfs/xfs_refcount.c |   52 +++++++++++++++---------------------------
 fs/xfs/libxfs/xfs_rmap.c     |   15 +++++++++---
 fs/xfs/xfs_fsops.c           |    5 ++++
 5 files changed, 37 insertions(+), 39 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index a840028..0f260eeb 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -1696,7 +1696,7 @@ xfs_free_ag_extent(
 	bno_cur = cnt_cur = NULL;
 	mp = tp->t_mountp;
 
-	if (oinfo->oi_owner != XFS_RMAP_OWN_UNKNOWN) {
+	if (oinfo->oi_owner != XFS_RMAP_OWN_NULL) {
 		error = xfs_rmap_free(tp, agbp, agno, bno, len, oinfo);
 		if (error)
 			goto error0;
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 16df627..89bb3d9 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -573,7 +573,7 @@ xfs_bmap_add_free(
 	if (oinfo)
 		new->xefi_oinfo = *oinfo;
 	else
-		xfs_rmap_skip_owner_update(&new->xefi_oinfo);
+		xfs_rmap_ag_owner(&new->xefi_oinfo, XFS_RMAP_OWN_NULL);
 	trace_xfs_bmap_free_defer(mp, XFS_FSB_TO_AGNO(mp, bno), 0,
 			XFS_FSB_TO_AGBNO(mp, bno), len);
 	xfs_defer_add(dfops, XFS_DEFER_OPS_TYPE_FREE, &new->xefi_list);
diff --git a/fs/xfs/libxfs/xfs_refcount.c b/fs/xfs/libxfs/xfs_refcount.c
index 73f8058..9103be0 100644
--- a/fs/xfs/libxfs/xfs_refcount.c
+++ b/fs/xfs/libxfs/xfs_refcount.c
@@ -1505,27 +1505,12 @@ __xfs_refcount_cow_alloc(
 	xfs_extlen_t		aglen,
 	struct xfs_defer_ops	*dfops)
 {
-	int			error;
-
 	trace_xfs_refcount_cow_increase(rcur->bc_mp, rcur->bc_private.a.agno,
 			agbno, aglen);
 
 	/* Add refcount btree reservation */
-	error = xfs_refcount_adjust_cow(rcur, agbno, aglen,
+	return xfs_refcount_adjust_cow(rcur, agbno, aglen,
 			XFS_REFCOUNT_ADJUST_COW_ALLOC, dfops);
-	if (error)
-		return error;
-
-	/* Add rmap entry */
-	if (xfs_sb_version_hasrmapbt(&rcur->bc_mp->m_sb)) {
-		error = xfs_rmap_alloc_extent(rcur->bc_mp, dfops,
-				rcur->bc_private.a.agno,
-				agbno, aglen, XFS_RMAP_OWN_COW);
-		if (error)
-			return error;
-	}
-
-	return error;
 }
 
 /*
@@ -1538,27 +1523,12 @@ __xfs_refcount_cow_free(
 	xfs_extlen_t		aglen,
 	struct xfs_defer_ops	*dfops)
 {
-	int			error;
-
 	trace_xfs_refcount_cow_decrease(rcur->bc_mp, rcur->bc_private.a.agno,
 			agbno, aglen);
 
 	/* Remove refcount btree reservation */
-	error = xfs_refcount_adjust_cow(rcur, agbno, aglen,
+	return xfs_refcount_adjust_cow(rcur, agbno, aglen,
 			XFS_REFCOUNT_ADJUST_COW_FREE, dfops);
-	if (error)
-		return error;
-
-	/* Remove rmap entry */
-	if (xfs_sb_version_hasrmapbt(&rcur->bc_mp->m_sb)) {
-		error = xfs_rmap_free_extent(rcur->bc_mp, dfops,
-				rcur->bc_private.a.agno,
-				agbno, aglen, XFS_RMAP_OWN_COW);
-		if (error)
-			return error;
-	}
-
-	return error;
 }
 
 /* Record a CoW staging extent in the refcount btree. */
@@ -1569,11 +1539,19 @@ xfs_refcount_alloc_cow_extent(
 	xfs_fsblock_t			fsb,
 	xfs_extlen_t			len)
 {
+	int				error;
+
 	if (!xfs_sb_version_hasreflink(&mp->m_sb))
 		return 0;
 
-	return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_ALLOC_COW,
+	error = __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_ALLOC_COW,
 			fsb, len);
+	if (error)
+		return error;
+
+	/* Add rmap entry */
+	return xfs_rmap_alloc_extent(mp, dfops, XFS_FSB_TO_AGNO(mp, fsb),
+			XFS_FSB_TO_AGBNO(mp, fsb), len, XFS_RMAP_OWN_COW);
 }
 
 /* Forget a CoW staging event in the refcount btree. */
@@ -1584,9 +1562,17 @@ xfs_refcount_free_cow_extent(
 	xfs_fsblock_t			fsb,
 	xfs_extlen_t			len)
 {
+	int				error;
+
 	if (!xfs_sb_version_hasreflink(&mp->m_sb))
 		return 0;
 
+	/* Remove rmap entry */
+	error = xfs_rmap_free_extent(mp, dfops, XFS_FSB_TO_AGNO(mp, fsb),
+			XFS_FSB_TO_AGBNO(mp, fsb), len, XFS_RMAP_OWN_COW);
+	if (error)
+		return error;
+
 	return __xfs_refcount_add(mp, dfops, XFS_REFCOUNT_FREE_COW,
 			fsb, len);
 }
diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c
index 5f3a3d9..fd0e630 100644
--- a/fs/xfs/libxfs/xfs_rmap.c
+++ b/fs/xfs/libxfs/xfs_rmap.c
@@ -484,10 +484,17 @@ xfs_rmap_unmap(
 	XFS_WANT_CORRUPTED_GOTO(mp, (flags & XFS_RMAP_UNWRITTEN) ==
 			(ltrec.rm_flags & XFS_RMAP_UNWRITTEN), out_error);
 
-	/* Make sure the extent we found covers the entire freeing range. */
-	XFS_WANT_CORRUPTED_GOTO(mp, ltrec.rm_startblock <= bno &&
-		ltrec.rm_startblock + ltrec.rm_blockcount >=
-		bno + len, out_error);
+	/*
+	 * Make sure the extent we found covers the entire freeing range.
+	 * If this is a wildcard free, we're already done, otherwise there's
+	 * something wrong with the rmapbt.
+	 */
+	if (ltrec.rm_startblock > bno ||
+	    ltrec.rm_startblock + ltrec.rm_blockcount < bno + len) {
+		if (owner == XFS_RMAP_OWN_UNKNOWN)
+			goto out_done;
+		XFS_WANT_CORRUPTED_GOTO(mp, false, out_error);
+	}
 
 	/* Make sure the owner matches what we expect to find in the tree. */
 	XFS_WANT_CORRUPTED_GOTO(mp, owner == ltrec.rm_owner ||
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 8f22fc5..60a2e12 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -571,6 +571,11 @@ xfs_growfs_data_private(
 		 * this doesn't actually exist in the rmap btree.
 		 */
 		xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_NULL);
+		error = xfs_rmap_free(tp, bp, agno,
+				be32_to_cpu(agf->agf_length) - new,
+				new, &oinfo);
+		if (error)
+			goto error0;
 		error = xfs_free_extent(tp,
 				XFS_AGB_TO_FSB(mp, agno,
 					be32_to_cpu(agf->agf_length) - new),