smb: client: make laundromat a delayed worker

By having laundromat kthread processing cached directories on every
second turned out to be overkill, especially when having multiple SMB
mounts.

Relax it by using a delayed worker instead that gets scheduled on
every @dir_cache_timeout (default=30) seconds per tcon.

This also fixes the 1s delay when tearing down tcon.

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/cached_dir.c b/fs/cifs/cached_dir.c
index e2be8aedb26e3a4c2a8655c9d020f76dffc71dd4..a9e5d3b7e9a0518fd004e0b65c24006127db97de 100644 (file)
--- a/fs/cifs/cached_dir.c
+++ b/fs/cifs/cached_dir.c
@@ -15,6 +15,7 @@
 static struct cached_fid *init_cached_dir(const char *path);
 static void free_cached_dir(struct cached_fid *cfid);
 static void smb2_close_cached_fid(struct kref *ref);
+static void cfids_laundromat_worker(struct work_struct *work);
 
 static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids,
                                                    const char *path,
@@ -572,53 +573,46 @@ static void free_cached_dir(struct cached_fid *cfid)
        kfree(cfid);
 }
 
-static int
-cifs_cfids_laundromat_thread(void *p)
+static void cfids_laundromat_worker(struct work_struct *work)
 {
-       struct cached_fids *cfids = p;
+       struct cached_fids *cfids;
        struct cached_fid *cfid, *q;
-       struct list_head entry;
+       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 * dir_cache_timeout)) {
-                               list_del(&cfid->entry);
-                               list_add(&cfid->entry, &entry);
-                               cfids->num_entries--;
-                       }
+       cfids = container_of(work, struct cached_fids, laundromat_work.work);
+
+       spin_lock(&cfids->cfid_list_lock);
+       list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
+               if (time_after(jiffies, cfid->time + HZ * dir_cache_timeout)) {
+                       list_move(&cfid->entry, &entry);
+                       cfids->num_entries--;
                }
-               spin_unlock(&cfids->cfid_list_lock);
+       }
+       spin_unlock(&cfids->cfid_list_lock);
 
-               list_for_each_entry_safe(cfid, q, &entry, entry) {
-                       cfid->on_list = false;
-                       list_del(&cfid->entry);
+       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) {
                        /*
-                        * Cancel, and wait for the work to finish in
-                        * case we are racing with it.
+                        * Our lease has not yet been cancelled from the server
+                        * so we need to drop the reference.
                         */
-                       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);
-                       }
+                       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;
+       queue_delayed_work(cifsiod_wq, &cfids->laundromat_work,
+                          dir_cache_timeout * HZ);
 }
 
-
 struct cached_fids *init_cached_dirs(void)
 {
        struct cached_fids *cfids;
@@ -629,19 +623,10 @@ struct cached_fids *init_cached_dirs(void)
        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;
-       }
+       INIT_DELAYED_WORK(&cfids->laundromat_work, cfids_laundromat_worker);
+       queue_delayed_work(cifsiod_wq, &cfids->laundromat_work,
+                          dir_cache_timeout * HZ);
+
        return cfids;
 }
 
@@ -657,11 +642,7 @@ void free_cached_dirs(struct cached_fids *cfids)
        if (cfids == NULL)
                return;
 
-       if (cfids->laundromat) {
-               kthread_stop(cfids->laundromat);
-               cfids->laundromat = NULL;
-               module_put(THIS_MODULE);
-       }
+       cancel_delayed_work_sync(&cfids->laundromat_work);
 
        spin_lock(&cfids->cfid_list_lock);
        list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {

diff --git a/fs/cifs/cached_dir.h b/fs/cifs/cached_dir.h
index a82ff2cea789c68b1ecdaf70dc489b593ed7227a..81ba0fd5cc16d6bd9bb782dc4a13f32a9b1322f5 100644 (file)
--- a/fs/cifs/cached_dir.h
+++ b/fs/cifs/cached_dir.h
@@ -57,7 +57,7 @@ struct cached_fids {
        spinlock_t cfid_list_lock;
        int num_entries;
        struct list_head entries;
-       struct task_struct *laundromat;
+       struct delayed_work laundromat_work;
 };
 
 extern struct cached_fids *init_cached_dirs(void);