From: Darrick J. Wong <djwong@kernel.org>
Date: Fri, 26 May 2023 13:16:03 +0000 (+0200)
Subject: xfs: give xfs_bmap_intent its own perag reference
X-Git-Tag: v6.4.0~61
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=32debad7cda40bfa9ecf094cee240f4ec12fb3f2;p=thirdparty%2Fxfsprogs-dev.git

xfs: give xfs_bmap_intent its own perag reference

Source kernel commit: 774a99b47b588bf0bd9f65d3b241d5bba0b2fcb0

Give the xfs_bmap_intent an active reference to the perag structure
data.  This reference will be used to enable scrub intent draining
functionality in subsequent patches.  Later, shrink will use these
passive references to know if an AG is quiesced or not.

The reason why we take a passive ref for a file mapping operation is
simple: we're committing to some sort of action involving space in an
AG, so we want to indicate our interest in that AG.  The space is
already allocated, so we need to be able to operate on AGs that are
offline or being shrunk.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
---

diff --git a/libxfs/defer_item.c b/libxfs/defer_item.c
index 285dc9a35..3dbcf1163 100644
--- a/libxfs/defer_item.c
+++ b/libxfs/defer_item.c
@@ -390,6 +390,26 @@ xfs_bmap_update_create_done(
 	return NULL;
 }
 
+/* Take a passive ref to the AG containing the space we're mapping. */
+void
+xfs_bmap_update_get_group(
+	struct xfs_mount	*mp,
+	struct xfs_bmap_intent	*bi)
+{
+	xfs_agnumber_t		agno;
+
+	agno = XFS_FSB_TO_AGNO(mp, bi->bi_bmap.br_startblock);
+	bi->bi_pag = xfs_perag_get(mp, agno);
+}
+
+/* Release a passive AG ref after finishing mapping work. */
+static inline void
+xfs_bmap_update_put_group(
+	struct xfs_bmap_intent	*bi)
+{
+	xfs_perag_put(bi->bi_pag);
+}
+
 /* Process a deferred rmap update. */
 STATIC int
 xfs_bmap_update_finish_item(
@@ -407,6 +427,8 @@ xfs_bmap_update_finish_item(
 		ASSERT(bi->bi_type == XFS_BMAP_UNMAP);
 		return -EAGAIN;
 	}
+
+	xfs_bmap_update_put_group(bi);
 	kmem_cache_free(xfs_bmap_intent_cache, bi);
 	return error;
 }
@@ -426,6 +448,8 @@ xfs_bmap_update_cancel_item(
 	struct xfs_bmap_intent		*bi;
 
 	bi = container_of(item, struct xfs_bmap_intent, bi_list);
+
+	xfs_bmap_update_put_group(bi);
 	kmem_cache_free(xfs_bmap_intent_cache, bi);
 }
 
diff --git a/libxfs/xfs_bmap.c b/libxfs/xfs_bmap.c
index 76591d077..4a7f3d280 100644
--- a/libxfs/xfs_bmap.c
+++ b/libxfs/xfs_bmap.c
@@ -6068,6 +6068,7 @@ __xfs_bmap_add(
 	bi->bi_whichfork = whichfork;
 	bi->bi_bmap = *bmap;
 
+	xfs_bmap_update_get_group(tp->t_mountp, bi);
 	xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_BMAP, &bi->bi_list);
 	return 0;
 }
diff --git a/libxfs/xfs_bmap.h b/libxfs/xfs_bmap.h
index dd08361ca..e5a492027 100644
--- a/libxfs/xfs_bmap.h
+++ b/libxfs/xfs_bmap.h
@@ -238,9 +238,13 @@ struct xfs_bmap_intent {
 	enum xfs_bmap_intent_type		bi_type;
 	int					bi_whichfork;
 	struct xfs_inode			*bi_owner;
+	struct xfs_perag			*bi_pag;
 	struct xfs_bmbt_irec			bi_bmap;
 };
 
+void xfs_bmap_update_get_group(struct xfs_mount *mp,
+		struct xfs_bmap_intent *bi);
+
 int	xfs_bmap_finish_one(struct xfs_trans *tp, struct xfs_bmap_intent *bi);
 void	xfs_bmap_map_extent(struct xfs_trans *tp, struct xfs_inode *ip,
 		struct xfs_bmbt_irec *imap);