cifs: Add a laundromat thread for cached directories

and drop cached directories after 30 seconds

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
index bfc964b..fe483f1 100644 (file)
--- a/fs/smb/client/cached_dir.c
+++ b/fs/smb/client/cached_dir.c
@@ -568,6 +568,53 @@ static void free_cached_dir(struct cached_fid *cfid)
        kfree(cfid);
 }
 
+static int
+cifs_cfids_laundromat_thread(void *p)
+{
+       struct cached_fids *cfids = p;
+       struct cached_fid *cfid, *q;
+       struct list_head entry;
+
+       while (!kthread_should_stop()) {
+               ssleep(1);
+               INIT_LIST_HEAD(&entry);
+               if (kthread_should_stop())
+                       return 0;
+               spin_lock(&cfids->cfid_list_lock);
+               list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
+                       if (time_after(jiffies, cfid->time + HZ * 30)) {
+                               list_del(&cfid->entry);
+                               list_add(&cfid->entry, &entry);
+                               cfids->num_entries--;
+                       }
+               }
+               spin_unlock(&cfids->cfid_list_lock);
+
+               list_for_each_entry_safe(cfid, q, &entry, entry) {
+                       cfid->on_list = false;
+                       list_del(&cfid->entry);
+                       /*
+                        * Cancel, and wait for the work to finish in
+                        * case we are racing with it.
+                        */
+                       cancel_work_sync(&cfid->lease_break);
+                       if (cfid->has_lease) {
+                               /*
+                                * We lease has not yet been cancelled from
+                                * the server so we need to drop the reference.
+                                */
+                               spin_lock(&cfids->cfid_list_lock);
+                               cfid->has_lease = false;
+                               spin_unlock(&cfids->cfid_list_lock);
+                               kref_put(&cfid->refcount, smb2_close_cached_fid);
+                       }
+               }
+       }
+
+       return 0;
+}
+
+
 struct cached_fids *init_cached_dirs(void)
 {
        struct cached_fids *cfids;
@@ -577,6 +624,20 @@ struct cached_fids *init_cached_dirs(void)
                return NULL;
        spin_lock_init(&cfids->cfid_list_lock);
        INIT_LIST_HEAD(&cfids->entries);
+
+       /*
+        * since we're in a cifs function already, we know that
+        * this will succeed. No need for try_module_get().
+        */
+       __module_get(THIS_MODULE);
+       cfids->laundromat = kthread_run(cifs_cfids_laundromat_thread,
+                                 cfids, "cifsd-cfid-laundromat");
+       if (IS_ERR(cfids->laundromat)) {
+               cifs_dbg(VFS, "Failed to start cfids laundromat thread.\n");
+               kfree(cfids);
+               module_put(THIS_MODULE);
+               return NULL;
+       }
        return cfids;
 }
 
@@ -589,6 +650,12 @@ void free_cached_dirs(struct cached_fids *cfids)
        struct cached_fid *cfid, *q;
        LIST_HEAD(entry);
 
+       if (cfids->laundromat) {
+               kthread_stop(cfids->laundromat);
+               cfids->laundromat = NULL;
+               module_put(THIS_MODULE);
+       }
+
        spin_lock(&cfids->cfid_list_lock);
        list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
                cfid->on_list = false;

diff --git a/fs/smb/client/cached_dir.h b/fs/smb/client/cached_dir.h
index 2f4e764..facc9b1 100644 (file)
--- a/fs/smb/client/cached_dir.h
+++ b/fs/smb/client/cached_dir.h
@@ -57,6 +57,7 @@ struct cached_fids {
        spinlock_t cfid_list_lock;
        int num_entries;
        struct list_head entries;
+       struct task_struct *laundromat;
 };
 
 extern struct cached_fids *init_cached_dirs(void);