[PATCH 2/9] smb/client: close cached notify handles on closedir

[ChenXiaoSong <chenxiaosong@chenxiaosong.com>]

From: ChenXiaoSong <chenxiaosong@kylinos.cn>

This patch was split out to make it easier to review.

Add storage for a change-notify FID in cifsFileInfo and close it from
the directory release path. This gives notify users a per-open lifetime
for the extra handle without changing how smb3_notify opens it yet.

Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
---
 fs/smb/client/cifsglob.h |  4 ++++
 fs/smb/client/file.c     | 30 ++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index 99f9e6dca62b..1250518997fb 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -1459,6 +1459,10 @@ struct cifsFileInfo {
 	int count;
 	spinlock_t file_info_lock; /* protects four flag/count fields above */
 	struct mutex fh_mutex; /* prevents reopen race after dead ses*/
+	struct mutex notify_fid_mutex;
+	struct cifs_fid notify_fid;
+	struct tcon_link *notify_tlink;
+	bool has_notify_fid:1;
 	struct cifs_search_info srch_inf;
 	struct work_struct oplock_break; /* work for oplock breaks */
 	struct work_struct put; /* work for the final part of _put */
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index f1e854f381d9..6cb4068fe06e 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -671,6 +671,7 @@ struct cifsFileInfo *cifs_new_dir_fileinfo(struct file *file,
 
 	spin_lock_init(&cfile->file_info_lock);
 	mutex_init(&cfile->fh_mutex);
+	mutex_init(&cfile->notify_fid_mutex);
 	cfile->invalidHandle = true;
 	cfile->tlink = cifs_get_tlink(tlink);
 
@@ -733,6 +734,7 @@ struct cifsFileInfo *cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
 	INIT_WORK(&cfile->serverclose, serverclose_work);
 	INIT_DELAYED_WORK(&cfile->deferred, smb2_deferred_work_close);
 	mutex_init(&cfile->fh_mutex);
+	mutex_init(&cfile->notify_fid_mutex);
 	spin_lock_init(&cfile->file_info_lock);
 
 	/*
@@ -1548,6 +1550,32 @@ cifs_reopen_persistent_handles(struct cifs_tcon *tcon)
 	}
 }
 
+static void cifs_close_notify_fid(unsigned int xid, struct cifsFileInfo *cfile)
+{
+	struct cifs_tcon *tcon;
+	struct TCP_Server_Info *server;
+	int rc = 0;
+
+	mutex_lock(&cfile->notify_fid_mutex);
+	if (!cfile->has_notify_fid)
+		goto unlock;
+
+	tcon = tlink_tcon(cfile->notify_tlink);
+	server = tcon->ses->server;
+	if (server->ops->close_dir)
+		rc = server->ops->close_dir(xid, tcon, &cfile->notify_fid);
+	else if (server->ops->close)
+		rc = server->ops->close(xid, tcon, &cfile->notify_fid);
+
+	cifs_dbg(FYI, "Closing cached notify handle with rc %d\n", rc);
+	cfile->has_notify_fid = false;
+	cifs_put_tlink(cfile->notify_tlink);
+	cfile->notify_tlink = NULL;
+
+unlock:
+	mutex_unlock(&cfile->notify_fid_mutex);
+}
+
 int cifs_closedir(struct inode *inode, struct file *file)
 {
 	int rc = 0;
@@ -1567,6 +1595,8 @@ int cifs_closedir(struct inode *inode, struct file *file)
 	server = tcon->ses->server;
 
 	cifs_dbg(FYI, "Freeing private data in close dir\n");
+	cifs_close_notify_fid(xid, cfile);
+
 	spin_lock(&cfile->file_info_lock);
 	if (server->ops->dir_needs_close(cfile)) {
 		cfile->invalidHandle = true;
-- 
2.54.0