From: Darrick J. Wong <djwong@kernel.org>
Date: Wed, 29 May 2024 04:13:30 +0000 (-0700)
Subject: xfs: enable realtime reflink
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=refs%2Fheads%2Fxfs-realtime-refcount-rebase;p=users%2Fhch%2Fxfs.git

xfs: enable realtime reflink

Enable reflink for realtime devices, sort of.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---

diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index db859d626272..2facc87a87f0 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -1224,9 +1224,11 @@ xfs_growfs_rt(
 		return -EINVAL;
 
 	/* Unsupported realtime features. */
-	if (!xfs_has_rtgroups(mp) && xfs_has_rmapbt(mp))
+	if (!xfs_has_rtgroups(mp) && (xfs_has_rmapbt(mp) || xfs_has_reflink(mp)))
 		return -EOPNOTSUPP;
-	if (xfs_has_reflink(mp) || xfs_has_quota(mp))
+	if (xfs_has_quota(mp))
+		return -EOPNOTSUPP;
+	if (xfs_has_reflink(mp) && in->extsize != 1)
 		return -EOPNOTSUPP;
 
 	error = xfs_sb_validate_fsb_count(&mp->m_sb, in->newblocks);
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index b9c65a3f3543..02e16cb52429 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1741,14 +1741,27 @@ xfs_fs_fill_super(
 "EXPERIMENTAL realtime superblock feature in use. Use at your own risk!");
 
 	if (xfs_has_reflink(mp)) {
-		if (mp->m_sb.sb_rblocks) {
+		/*
+		 * Reflink doesn't support rt extent sizes larger than a single
+		 * block because we would have to perform unshare-around for
+		 * rtext-unaligned write requests.
+		 */
+		if (xfs_has_realtime(mp) && mp->m_sb.sb_rextsize != 1) {
 			xfs_alert(mp,
-	"reflink not compatible with realtime device!");
+	"reflink not compatible with realtime extent size %u!",
+					mp->m_sb.sb_rextsize);
 			error = -EINVAL;
 			goto out_filestream_unmount;
 		}
 
-		if (xfs_globals.always_cow) {
+		/*
+		 * always-cow mode is not supported on filesystems with rt
+		 * extent sizes larger than a single block because we'd have
+		 * to perform write-around for unaligned writes because remap
+		 * requests must be aligned to an rt extent.
+		 */
+		if (xfs_globals.always_cow &&
+		    (!xfs_has_realtime(mp) || mp->m_sb.sb_rextsize == 1)) {
 			xfs_info(mp, "using DEBUG-only always_cow mode.");
 			mp->m_always_cow = true;
 		}