From 8de360960afc474ddbeff2f7ade7824cf74dcc1c Mon Sep 17 00:00:00 2001
From: Kotresh HR <khiremat@redhat.com>
Date: Wed, 19 Feb 2025 00:19:14 +0530
Subject: [PATCH] mds: Commit referent inode to disk

Hardlink referent inode plumbing work continues.
This patch adds the capability to commit the
referent inode created (would be part of hardlink
operation) to the disk.

The referent inode is marked with 'r'. If the
recovery tools recover the referent inode,
it's marked with 'R'

Fixes: https://tracker.ceph.com/issues/54205
Signed-off-by: Kotresh HR <khiremat@redhat.com>
---
 src/mds/CDir.cc | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 src/mds/CDir.h  |  1 +
 2 files changed, 47 insertions(+)

diff --git a/src/mds/CDir.cc b/src/mds/CDir.cc
index 0e406086d4cfe..ad8c419c5e0a6 100644
--- a/src/mds/CDir.cc
+++ b/src/mds/CDir.cc
@@ -2602,6 +2602,14 @@ void CDir::_omap_commit_ops(int r, int op_prio, int64_t metapool, version_t vers
     if (item.is_remote) {
       // remote link
       CDentry::encode_remote(item.ino, item.d_type, item.alternate_name, bl);
+    } else if (item.is_referent_remote) {
+      // marker, name, inode, [symlink string]
+      bl.append('r');         // inode
+
+      ENCODE_START(2, 1, bl);
+      encode(item.alternate_name, bl);
+      _encode_primary_inode_base(item, dfts, bl);
+      ENCODE_FINISH(bl);
     } else {
       // marker, name, inode, [symlink string]
       bl.append('i');         // inode
@@ -2749,6 +2757,27 @@ void CDir::_parse_dentry(CDentry *dn, dentry_commit_item &item,
     item.ino = linkage.get_remote_ino();
     item.d_type = linkage.get_remote_d_type();
     dout(14) << " dn '" << dn->get_name() << "' remote ino " << item.ino << dendl;
+  } else if (linkage.is_referent_remote()) {
+    // referent link
+    item.is_referent_remote = true;
+    item.ino = linkage.get_remote_ino();
+    item.d_type = linkage.get_remote_d_type();
+
+    CInode *in = linkage.get_referent_inode();
+    ceph_assert(in);
+
+    dout(14) << __func__ << " dn '" << dn->get_name() << "' referent inode " << *in << " remote ino " << item.ino << dendl;
+
+    item.features = mdcache->mds->mdsmap->get_up_features();
+    item.inode = in->inode;
+    if (in->inode->is_symlink())
+      item.symlink = in->symlink;
+    using ceph::encode;
+    encode(in->dirfragtree, bl);
+    item.xattrs = in->xattrs;
+    item.old_inodes = in->old_inodes;
+    item.oldest_snap = in->oldest_snap;
+    item.damage_flags = in->damage_flags;
   } else if (linkage.is_primary()) {
     // primary link
     CInode *in = linkage.get_inode();
@@ -2882,6 +2911,23 @@ void CDir::_committed(int r, version_t v)
     CDentry *dn = *p;
     ++p;
     
+    // referent inode
+    if (dn->linkage.is_referent_remote()) {
+      CInode *in = dn->linkage.get_referent_inode();
+      ceph_assert(in);
+      ceph_assert(in->is_auth());
+
+      if (committed_version >= in->get_version()) {
+	if (in->is_dirty()) {
+	  dout(15) << __func__ << " referent inode - dir " << committed_version << " >= inode " << in->get_version() << " now clean " << *in << dendl;
+	  in->mark_clean();
+	}
+      } else {
+	dout(15) << __func__ << " referent inode - dir " << committed_version << " < inode " << in->get_version() << " still dirty " << *in << dendl;
+	ceph_assert(in->is_dirty() || in->last < CEPH_NOSNAP);  // special case for cow snap items (not predirtied)
+      }
+    }
+
     // inode?
     if (dn->linkage.is_primary()) {
       CInode *in = dn->linkage.get_inode();
diff --git a/src/mds/CDir.h b/src/mds/CDir.h
index 9c477eac59829..bfdb363d98a5f 100644
--- a/src/mds/CDir.h
+++ b/src/mds/CDir.h
@@ -61,6 +61,7 @@ public:
     std::string key;
     snapid_t first;
     bool is_remote = false;
+    bool is_referent_remote = false;
 
     inodeno_t ino;
     unsigned char d_type;
-- 
2.39.5