From dfe33f9abc08997e56f9bdf14fe9ac7ac0e14075 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Tue, 30 Oct 2018 19:50:31 -0500
Subject: [PATCH] smb3: allow more detailed protocol info on open files for
 debugging
Git-commit: dfe33f9abc08997e56f9bdf14fe9ac7ac0e14075
Patch-mainline: v4.20-rc1
References: bsc#1144333

In order to debug complex problems it is often helpful to
have detailed information on the client and server view
of the open file information.  Add the ability for root to
view the list of smb3 open files and dump the persistent
handle and other info so that it can be more easily
correlated with server logs.

Sample output from "cat /proc/fs/cifs/open_files"

 # Version:1
 # Format:
 # <tree id> <persistent fid> <flags> <count> <pid> <uid> <filename> <mid>
 0x5 0x800000378 0x8000 1 7704 0 some-file 0x14
 0xcb903c0c 0x84412e67 0x8000 1 7754 1001 rofile 0x1a6d
 0xcb903c0c 0x9526b767 0x8000 1 7720 1000 file 0x1a5b
 0xcb903c0c 0x9ce41a21 0x8000 1 7715 0 smallfile 0xd67

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Acked-by: Paulo Alcantara <palcantara@suse.de>
---
 fs/cifs/cifs_debug.c |   69 +++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/cifs/cifsglob.h   |    3 ++
 fs/cifs/smb2ops.c    |    3 ++
 fs/cifs/smb2pdu.c    |    3 ++
 4 files changed, 78 insertions(+)

--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -145,6 +145,58 @@ cifs_dump_iface(struct seq_file *m, stru
 		seq_printf(m, "\t\tIPv6: %pI6\n", &ipv6->sin6_addr);
 }
 
+static int cifs_debug_files_proc_show(struct seq_file *m, void *v)
+{
+	struct list_head *stmp, *tmp, *tmp1, *tmp2;
+	struct TCP_Server_Info *server;
+	struct cifs_ses *ses;
+	struct cifs_tcon *tcon;
+	struct cifsFileInfo *cfile;
+
+	seq_puts(m, "# Version:1\n");
+	seq_puts(m, "# Format:\n");
+	seq_puts(m, "# <tree id> <persistent fid> <flags> <count> <pid> <uid>");
+#ifdef CONFIG_CIFS_DEBUG2
+	seq_printf(m, " <filename> <mid>\n");
+#else
+	seq_printf(m, " <filename>\n");
+#endif /* CIFS_DEBUG2 */
+	spin_lock(&cifs_tcp_ses_lock);
+	list_for_each(stmp, &cifs_tcp_ses_list) {
+		server = list_entry(stmp, struct TCP_Server_Info,
+				    tcp_ses_list);
+		list_for_each(tmp, &server->smb_ses_list) {
+			ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
+			list_for_each(tmp1, &ses->tcon_list) {
+				tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
+				spin_lock(&tcon->open_file_lock);
+				list_for_each(tmp2, &tcon->openFileList) {
+					cfile = list_entry(tmp2, struct cifsFileInfo,
+						     tlist);
+					seq_printf(m,
+						"0x%x 0x%llx 0x%x %d %d %d %s",
+						tcon->tid,
+						cfile->fid.persistent_fid,
+						cfile->f_flags,
+						cfile->count,
+						cfile->pid,
+						from_kuid(&init_user_ns, cfile->uid),
+						cfile->dentry->d_name.name);
+#ifdef CONFIG_CIFS_DEBUG2
+					seq_printf(m, " 0x%llx\n", cfile->fid.mid);
+#else
+					seq_printf(m, "\n");
+#endif /* CIFS_DEBUG2 */
+				}
+				spin_unlock(&tcon->open_file_lock);
+			}
+		}
+	}
+	spin_unlock(&cifs_tcp_ses_lock);
+	seq_putc(m, '\n');
+	return 0;
+}
+
 static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
 {
 	struct list_head *tmp1, *tmp2, *tmp3;
@@ -566,6 +618,7 @@ static const struct file_operations cifs
 static const struct file_operations traceSMB_proc_fops;
 static const struct file_operations cifs_security_flags_proc_fops;
 static const struct file_operations cifs_linux_ext_proc_fops;
+static const struct file_operations cifs_debug_files_proc_fops;
 
 void
 cifs_proc_init(void)
@@ -576,6 +629,9 @@ cifs_proc_init(void)
 
 	proc_create("DebugData", 0, proc_fs_cifs, &cifs_debug_data_proc_fops);
 
+	proc_create("open_files", 0400, proc_fs_cifs,
+		    &cifs_debug_files_proc_fops);
+
 	proc_create("Stats", 0644, proc_fs_cifs, &cifs_stats_proc_fops);
 	proc_create("cifsFYI", 0644, proc_fs_cifs, &cifsFYI_proc_fops);
 	proc_create("traceSMB", 0644, proc_fs_cifs, &traceSMB_proc_fops);
@@ -612,6 +668,7 @@ cifs_proc_clean(void)
 		return;
 
 	remove_proc_entry("DebugData", proc_fs_cifs);
+	remove_proc_entry("open_files", proc_fs_cifs);
 	remove_proc_entry("cifsFYI", proc_fs_cifs);
 	remove_proc_entry("traceSMB", proc_fs_cifs);
 	remove_proc_entry("Stats", proc_fs_cifs);
@@ -873,6 +930,18 @@ static const struct file_operations cifs
 	.release	= single_release,
 	.write		= cifs_security_flags_proc_write,
 };
+
+static int cifs_debug_files_proc_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, cifs_debug_files_proc_show, NULL);
+}
+
+static const struct file_operations cifs_debug_files_proc_fops = {
+	.open		= cifs_debug_files_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
 #else
 inline void cifs_proc_init(void)
 {
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1125,6 +1125,9 @@ struct cifs_fid {
 	__u8 create_guid[16];
 	struct cifs_pending_open *pending_open;
 	unsigned int epoch;
+#ifdef CONFIG_CIFS_DEBUG2
+	__u64 mid;
+#endif /* CIFS_DEBUG2 */
 	bool purge_cache;
 };
 
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1079,6 +1079,9 @@ smb2_set_fid(struct cifsFileInfo *cfile,
 
 	cfile->fid.persistent_fid = fid->persistent_fid;
 	cfile->fid.volatile_fid = fid->volatile_fid;
+#ifdef CONFIG_CIFS_DEBUG2
+	cfile->fid.mid = fid->mid;
+#endif /* CIFS_DEBUG2 */
 	server->ops->set_oplock_level(cinode, oplock, fid->epoch,
 				      &fid->purge_cache);
 	cinode->can_cache_brlcks = CIFS_CACHE_WRITE(cinode);
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2309,6 +2309,9 @@ SMB2_open(const unsigned int xid, struct
 	atomic_inc(&tcon->num_remote_opens);
 	oparms->fid->persistent_fid = rsp->PersistentFileId;
 	oparms->fid->volatile_fid = rsp->VolatileFileId;
+#ifdef CONFIG_CIFS_DEBUG2
+	oparms->fid->mid = le64_to_cpu(rsp->sync_hdr.MessageId);
+#endif /* CIFS_DEBUG2 */
 
 	if (buf) {
 		memcpy(buf, &rsp->CreationTime, 32);