From 601dd3b79769b38d30b693c40afdb2a4b7edf9d0 Mon Sep 17 00:00:00 2001 From: Shyam Prasad N Date: Sun, 1 Feb 2026 00:21:13 +0530 Subject: [PATCH] cifs: Fix locking usage for tcon fields [ Upstream commit 96c4af418586ee9a6aab61738644366426e05316 ] We used to use the cifs_tcp_ses_lock to protect a lot of objects that are not just the server, ses or tcon lists. We later introduced srv_lock, ses_lock and tc_lock to protect fields within the corresponding structs. This was done to provide a more granular protection and avoid unnecessary serialization. There were still a couple of uses of cifs_tcp_ses_lock to provide tcon fields. In this patch, I've replaced them with tc_lock. Cc: stable@vger.kernel.org Signed-off-by: Shyam Prasad N Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/smb/client/cached_dir.c | 4 ++-- fs/smb/client/smb2misc.c | 6 +++--- fs/smb/client/smb2ops.c | 8 +++----- fs/smb/client/smb2pdu.c | 2 ++ fs/smb/client/trace.h | 1 + 5 files changed, 11 insertions(+), 10 deletions(-) diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c index e92a61e934e4..d83161285a17 100644 --- a/fs/smb/client/cached_dir.c +++ b/fs/smb/client/cached_dir.c @@ -769,11 +769,11 @@ static void cfids_laundromat_worker(struct work_struct *work) dput(dentry); if (cfid->is_open) { - spin_lock(&cifs_tcp_ses_lock); + spin_lock(&cfid->tcon->tc_lock); ++cfid->tcon->tc_count; trace_smb3_tcon_ref(cfid->tcon->debug_id, cfid->tcon->tc_count, netfs_trace_tcon_ref_get_cached_laundromat); - spin_unlock(&cifs_tcp_ses_lock); + spin_unlock(&cfid->tcon->tc_lock); queue_work(serverclose_wq, &cfid->close_work); } else /* diff --git a/fs/smb/client/smb2misc.c b/fs/smb/client/smb2misc.c index cddf273c14ae..5a820176b6f0 100644 --- a/fs/smb/client/smb2misc.c +++ b/fs/smb/client/smb2misc.c @@ -807,14 +807,14 @@ smb2_handle_cancelled_close(struct cifs_tcon *tcon, __u64 persistent_fid, int rc; cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count); - spin_lock(&cifs_tcp_ses_lock); + spin_lock(&tcon->tc_lock); if (tcon->tc_count <= 0) { struct TCP_Server_Info *server = NULL; trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, netfs_trace_tcon_ref_see_cancelled_close); WARN_ONCE(tcon->tc_count < 0, "tcon refcount is negative"); - spin_unlock(&cifs_tcp_ses_lock); + spin_unlock(&tcon->tc_lock); if (tcon->ses) { server = tcon->ses->server; @@ -828,7 +828,7 @@ smb2_handle_cancelled_close(struct cifs_tcon *tcon, __u64 persistent_fid, tcon->tc_count++; trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, netfs_trace_tcon_ref_get_cancelled_close); - spin_unlock(&cifs_tcp_ses_lock); + spin_unlock(&tcon->tc_lock); rc = __smb2_handle_cancelled_cmd(tcon, SMB2_CLOSE_HE, 0, persistent_fid, volatile_fid); diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index 300573be10bc..b53b18c18739 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -3000,7 +3000,9 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses, struct cifs_tcon, tcon_list); if (tcon) { + spin_lock(&tcon->tc_lock); tcon->tc_count++; + spin_unlock(&tcon->tc_lock); trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, netfs_trace_tcon_ref_get_dfs_refer); } @@ -3065,13 +3067,9 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses, out: if (tcon && !tcon->ipc) { /* ipc tcons are not refcounted */ - spin_lock(&cifs_tcp_ses_lock); - tcon->tc_count--; + cifs_put_tcon(tcon, netfs_trace_tcon_ref_put_dfs_refer); trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, netfs_trace_tcon_ref_dec_dfs_refer); - /* tc_count can never go negative */ - WARN_ON(tcon->tc_count < 0); - spin_unlock(&cifs_tcp_ses_lock); } kfree(utf16_path); kfree(dfs_req); diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c index b0ff9f7e8cea..89b447f6e3eb 100644 --- a/fs/smb/client/smb2pdu.c +++ b/fs/smb/client/smb2pdu.c @@ -4180,7 +4180,9 @@ void smb2_reconnect_server(struct work_struct *work) list_for_each_entry(tcon, &ses->tcon_list, tcon_list) { if (tcon->need_reconnect || tcon->need_reopen_files) { + spin_lock(&tcon->tc_lock); tcon->tc_count++; + spin_unlock(&tcon->tc_lock); trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, netfs_trace_tcon_ref_get_reconnect_server); list_add_tail(&tcon->rlist, &tmp_list); diff --git a/fs/smb/client/trace.h b/fs/smb/client/trace.h index 9c3cc7c3300c..fb9c631e0ec1 100644 --- a/fs/smb/client/trace.h +++ b/fs/smb/client/trace.h @@ -59,6 +59,7 @@ EM(netfs_trace_tcon_ref_put_cancelled_close_fid, "PUT Cn-Fid") \ EM(netfs_trace_tcon_ref_put_cancelled_mid, "PUT Cn-Mid") \ EM(netfs_trace_tcon_ref_put_mnt_ctx, "PUT MntCtx") \ + EM(netfs_trace_tcon_ref_put_dfs_refer, "PUT DfsRfr") \ EM(netfs_trace_tcon_ref_put_reconnect_server, "PUT Reconn") \ EM(netfs_trace_tcon_ref_put_tlink, "PUT Tlink ") \ EM(netfs_trace_tcon_ref_see_cancelled_close, "SEE Cn-Cls") \