Updated patch to remove dumping of flags (tcon->Flags was already
supposed to be dumped via
the other ioctl (CIFS_IOC_GET_MNT_INFO) but it had a minor bug - will
send followon patch for that)
On Thu, Nov 9, 2023 at 3:51 PM Steve French <smfrench@xxxxxxxxx> wrote:
>
> [PATCH] smb3: allow debugging session and tcon info to improve stats
> analysis and debugging
>
> When multiple mounts are to the same share from the same client it was not
> possible to determine which section of /proc/fs/cifs/Stats (and DebugData)
> correspond to that mount. In some recent examples this turned out to be
> a significant problem when trying to analyze performance problems - since
> there are many cases where unless we know the tree id and session id we
> can't figure out which stats (e.g. number of SMB3.1.1 requests by type,
> the total time they take, which is slowest, how many fail etc.) apply to
> which mount.
>
> Add an ioctl to return tid, session id, tree connect count and tcon flags.
>
> --
> Thanks,
>
> Steve
--
Thanks,
Steve
From 003ffa326df481486de61d761855126d968184ac Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@xxxxxxxxxxxxx>
Date: Thu, 9 Nov 2023 15:28:12 -0600
Subject: [PATCH] smb3: allow dumping session and tcon id to improve stats
analysis and debugging
When multiple mounts are to the same share from the same client it was not
possible to determine which section of /proc/fs/cifs/Stats (and DebugData)
correspond to that mount. In some recent examples this turned out to be
a significant problem when trying to analyze performance data - since
there are many cases where unless we know the tree id and session id we
can't figure out which stats (e.g. number of SMB3.1.1 requests by type,
the total time they take, which is slowest, how many fail etc.) apply to
which mount. The only existing loosely related ioctl CIFS_IOC_GET_MNT_INFO
does not return the information needed to uniquely identify which tcon
is which mount although it does return various flags and device info.
Add a cifs.ko ioctl CIFS_IOC_GET_TCON_INFO (0x8010cf0c) to return tid,
session id, tree connect count.
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
foo
---
fs/smb/client/cifs_ioctl.h | 7 +++++++
fs/smb/client/ioctl.c | 25 +++++++++++++++++++++++++
2 files changed, 32 insertions(+)
diff --git a/fs/smb/client/cifs_ioctl.h b/fs/smb/client/cifs_ioctl.h
index 332588e77c31..71bdce7ea60c 100644
--- a/fs/smb/client/cifs_ioctl.h
+++ b/fs/smb/client/cifs_ioctl.h
@@ -26,6 +26,12 @@ struct smb_mnt_fs_info {
__u64 cifs_posix_caps;
} __packed;
+struct smb_mnt_tcon_info {
+ __u32 tid;
+ __u64 session_id;
+ int tc_count;
+} __packed;
+
struct smb_snapshot_array {
__u32 number_of_snapshots;
__u32 number_of_snapshots_returned;
@@ -108,6 +114,7 @@ struct smb3_notify_info {
#define CIFS_IOC_NOTIFY _IOW(CIFS_IOCTL_MAGIC, 9, struct smb3_notify)
#define CIFS_DUMP_FULL_KEY _IOWR(CIFS_IOCTL_MAGIC, 10, struct smb3_full_key_debug_info)
#define CIFS_IOC_NOTIFY_INFO _IOWR(CIFS_IOCTL_MAGIC, 11, struct smb3_notify_info)
+#define CIFS_IOC_GET_TCON_INFO _IOR(CIFS_IOCTL_MAGIC, 12, struct smb_mnt_tcon_info)
#define CIFS_IOC_SHUTDOWN _IOR('X', 125, __u32)
/*
diff --git a/fs/smb/client/ioctl.c b/fs/smb/client/ioctl.c
index f7160003e0ed..f13730750e84 100644
--- a/fs/smb/client/ioctl.c
+++ b/fs/smb/client/ioctl.c
@@ -117,6 +117,21 @@ static long cifs_ioctl_copychunk(unsigned int xid, struct file *dst_file,
return rc;
}
+static long smb_mnt_get_tcon_info(struct cifs_tcon *tcon, void __user *arg)
+{
+ int rc = 0;
+ struct smb_mnt_tcon_info tcon_inf;
+
+ tcon_inf.tid = tcon->tid;
+ tcon_inf.session_id = tcon->ses->Suid;
+ tcon_inf.tc_count = tcon->tc_count;
+
+ if (copy_to_user(arg, &tcon_inf, sizeof(struct smb_mnt_tcon_info)))
+ rc = -EFAULT;
+
+ return rc;
+}
+
static long smb_mnt_get_fsinfo(unsigned int xid, struct cifs_tcon *tcon,
void __user *arg)
{
@@ -414,6 +429,16 @@ long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
tcon = tlink_tcon(pSMBFile->tlink);
rc = smb_mnt_get_fsinfo(xid, tcon, (void __user *)arg);
break;
+ case CIFS_IOC_GET_TCON_INFO:
+ cifs_sb = CIFS_SB(inode->i_sb);
+ tlink = cifs_sb_tlink(cifs_sb);
+ if (IS_ERR(tlink)) {
+ rc = PTR_ERR(tlink);
+ break;
+ }
+ tcon = tlink_tcon(tlink);
+ rc = smb_mnt_get_tcon_info(tcon, (void __user *)arg);
+ break;
case CIFS_ENUMERATE_SNAPSHOTS:
if (pSMBFile == NULL)
break;
--
2.39.2
