NFS: Add tracepoints for debugging NFS hard links

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 72 insertions, 0 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index dca7deb1609b..4ce7f7696e11 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1860,6 +1860,7 @@ nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
                 old_dentry->d_parent->d_name.name, old_dentry->d_name.name,
                 dentry->d_parent->d_name.name, dentry->d_name.name);
 
+        trace_nfs_link_enter(inode, dir, dentry);
         NFS_PROTO(inode)->return_delegation(inode);
 
         d_drop(dentry);
@@ -1868,6 +1869,7 @@ nfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
                 ihold(inode);
                 d_add(dentry, inode);
         }
+        trace_nfs_link_exit(inode, dir, dentry, error);
         return error;
 }
 EXPORT_SYMBOL_GPL(nfs_link);
diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h
index a20f0d147cf2..89fe741e58b1 100644
--- a/fs/nfs/nfstrace.h
+++ b/fs/nfs/nfstrace.h
@@ -512,6 +512,76 @@ DEFINE_NFS_DIRECTORY_EVENT_DONE(nfs_unlink_exit);
 DEFINE_NFS_DIRECTORY_EVENT(nfs_symlink_enter);
 DEFINE_NFS_DIRECTORY_EVENT_DONE(nfs_symlink_exit);
 
+TRACE_EVENT(nfs_link_enter,
+                TP_PROTO(
+                        const struct inode *inode,
+                        const struct inode *dir,
+                        const struct dentry *dentry
+                ),
+
+                TP_ARGS(inode, dir, dentry),
+
+                TP_STRUCT__entry(
+                        __field(dev_t, dev)
+                        __field(u64, fileid)
+                        __field(u64, dir)
+                        __string(name, dentry->d_name.name)
+                ),
+
+                TP_fast_assign(
+                        __entry->dev = inode->i_sb->s_dev;
+                        __entry->fileid = NFS_FILEID(inode);
+                        __entry->dir = NFS_FILEID(dir);
+                        __assign_str(name, dentry->d_name.name);
+                ),
+
+                TP_printk(
+                        "fileid=%02x:%02x:%llu name=%02x:%02x:%llu/%s",
+                        MAJOR(__entry->dev), MINOR(__entry->dev),
+                        __entry->fileid,
+                        MAJOR(__entry->dev), MINOR(__entry->dev),
+                        (unsigned long long)__entry->dir,
+                        __get_str(name)
+                )
+);
+
+TRACE_EVENT(nfs_link_exit,
+                TP_PROTO(
+                        const struct inode *inode,
+                        const struct inode *dir,
+                        const struct dentry *dentry,
+                        int error
+                ),
+
+                TP_ARGS(inode, dir, dentry, error),
+
+                TP_STRUCT__entry(
+                        __field(int, error)
+                        __field(dev_t, dev)
+                        __field(u64, fileid)
+                        __field(u64, dir)
+                        __string(name, dentry->d_name.name)
+                ),
+
+                TP_fast_assign(
+                        __entry->dev = inode->i_sb->s_dev;
+                        __entry->fileid = NFS_FILEID(inode);
+                        __entry->dir = NFS_FILEID(dir);
+                        __entry->error = error;
+                        __assign_str(name, dentry->d_name.name);
+                ),
+
+                TP_printk(
+                        "error=%d fileid=%02x:%02x:%llu name=%02x:%02x:%llu/%s",
+                        __entry->error,
+                        MAJOR(__entry->dev), MINOR(__entry->dev),
+                        __entry->fileid,
+                        MAJOR(__entry->dev), MINOR(__entry->dev),
+                        (unsigned long long)__entry->dir,
+                        __get_str(name)
+                )
+);
+
 DECLARE_EVENT_CLASS(nfs_rename_event,
                 TP_PROTO(
                         const struct inode *old_dir,