smb3: allow more detailed protocol info on open files for debugging

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>

1 files changed, 56 insertions, 0 deletions

diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 3e812428ac8d..ba178b09de0b 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -145,6 +145,58 @@ cifs_dump_iface(struct seq_file *m, struct cifs_server_iface *iface)
 		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;
@@ -565,6 +617,9 @@ cifs_proc_init(void)
 	proc_create_single("DebugData", 0, proc_fs_cifs,
 			cifs_debug_data_proc_show);
 
+	proc_create_single("open_files", 0400, proc_fs_cifs,
+			cifs_debug_files_proc_show);
+
 	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);
@@ -601,6 +656,7 @@ 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);