smb: client: remove cached_fids->dying list

Since any cleanup is done on laundromat, the dying list can be removed.

- entries stays on the main list until they're schedule for cleanup
  (->last_access_time = 1)
- cached_fids->num_entries is decremented only when cfid transitions
  from on_list true -> false

cached_fid lifecycle on the list becomes:
- list_add() on find_or_create_cached_dir()
- list_move() to local list on laundromat
- list_del_init() from local list
- list_del() on release callback

Other changes:
- add invalidate_cfid() helper to centralize cfid invalidation criteria

Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>

2 files changed, 28 insertions, 58 deletions

diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
index 8912c27cbc23..af2fe416ddcf 100644
--- a/fs/smb/client/cached_dir.c
+++ b/fs/smb/client/cached_dir.c
@@ -22,6 +22,18 @@ struct cached_dir_dentry {
 	struct dentry *dentry;
 };
 
+static inline void invalidate_cfid(struct cached_fid *cfid, bool force_expire)
+{
+	if (cfid->on_list)
+		cfid->cfids->num_entries--;
+
+	/* do not change other fields here! */
+	cfid->on_list = false;
+	cfid->time = 0;
+	if (force_expire)
+		cfid->last_access_time = 1;
+}
+
 static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids,
 						    const char *path,
 						    bool lookup_only,
@@ -437,11 +449,8 @@ smb2_close_cached_fid(struct kref *ref)
 	struct cached_fid *cfid = container_of(ref, struct cached_fid, refcount);
 
 	spin_lock(&cfid->cfids->cfid_list_lock);
-	if (cfid->on_list) {
-		list_del(&cfid->entry);
-		cfid->on_list = false;
-		cfid->cfids->num_entries--;
-	}
+	list_del(&cfid->entry);
+	invalidate_cfid(cfid, true);
 	spin_unlock(&cfid->cfids->cfid_list_lock);
 
 	dput(cfid->dentry);
@@ -461,15 +470,13 @@ void drop_cached_dir_by_name(const unsigned int xid, struct cifs_tcon *tcon,
 		cifs_dbg(FYI, "no cached dir found for rmdir(%s)\n", name);
 		return;
 	}
+
 	spin_lock(&cfid->cfids->cfid_list_lock);
-	if (cfid->has_lease) {
-		cfid->has_lease = false;
-		kref_put(&cfid->refcount, smb2_close_cached_fid);
-	}
+	invalidate_cfid(cfid, false);
 	spin_unlock(&cfid->cfids->cfid_list_lock);
-	close_cached_dir(cfid);
-}
 
+	kref_put(&cfid->refcount, smb2_close_cached_fid);
+}
 
 void close_cached_dir(struct cached_fid *cfid)
 {
@@ -550,25 +557,11 @@ void invalidate_all_cached_dirs(struct cifs_tcon *tcon)
 	if (!cfids)
 		return;
 
-	/*
-	 * Mark all the cfids as closed, and move them to the cfids->dying list.
-	 * They'll be cleaned up by laundromat.  Take a reference to each cfid
-	 * during this process.
-	 */
+	/* Mark all the cfids as closed, and invalidate them for laundromat cleanup. */
 	spin_lock(&cfids->cfid_list_lock);
 	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
-		list_move(&cfid->entry, &cfids->dying);
-		cfids->num_entries--;
+		invalidate_cfid(cfid, true);
 		cfid->is_open = false;
-		cfid->on_list = false;
-		if (cfid->has_lease) {
-			/*
-			 * The lease was never cancelled from the server,
-			 * so steal that reference.
-			 */
-			cfid->has_lease = false;
-		} else
-			kref_get(&cfid->refcount);
 	}
 	spin_unlock(&cfids->cfid_list_lock);
 
@@ -592,17 +585,13 @@ bool cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16])
 		    !memcmp(lease_key,
 			    cfid->fid.lease_key,
 			    SMB2_LEASE_KEY_SIZE)) {
-			cfid->has_lease = false;
-			cfid->time = 0;
-
 			/*
-			 * We found a lease, move it to the dying list and schedule immediate
-			 * cleanup on laundromat.
+			 * We found a lease, invalidate cfid and schedule immediate cleanup on
+			 * laundromat.
 			 * No need to take a ref here, as we still hold our initial one.
 			 */
-			list_move(&cfid->entry, &cfids->dying);
-			cfids->num_entries--;
-			cfid->on_list = false;
+			invalidate_cfid(cfid, true);
+			cfid->has_lease = false;
 			found = true;
 			break;
 		}
@@ -667,29 +656,17 @@ static void cfids_laundromat_worker(struct work_struct *work)
 	cfids = container_of(work, struct cached_fids, laundromat_work.work);
 
 	spin_lock(&cfids->cfid_list_lock);
-	/* move cfids->dying to the local list */
-	list_cut_before(&entry, &cfids->dying, &cfids->dying);
-
 	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
 		if (cfid->last_access_time &&
 		    time_after(jiffies, cfid->last_access_time + HZ * dir_cache_timeout)) {
-			cfid->on_list = false;
+			invalidate_cfid(cfid, true);
 			list_move(&cfid->entry, &entry);
-			cfids->num_entries--;
-			if (cfid->has_lease) {
-				/*
-				 * Our lease has not yet been cancelled from the
-				 * server. Steal that reference.
-				 */
-				cfid->has_lease = false;
-			} else
-				kref_get(&cfid->refcount);
 		}
 	}
 	spin_unlock(&cfids->cfid_list_lock);
 
 	list_for_each_entry_safe(cfid, q, &entry, entry) {
-		list_del(&cfid->entry);
+		list_del_init(&cfid->entry);
 
 		/*
 		 * If a cfid reached here, we must cleanup anything unrelated to it, i.e. dentry and
@@ -732,7 +709,6 @@ struct cached_fids *init_cached_dirs(void)
 		return NULL;
 	spin_lock_init(&cfids->cfid_list_lock);
 	INIT_LIST_HEAD(&cfids->entries);
-	INIT_LIST_HEAD(&cfids->dying);
 
 	INIT_DELAYED_WORK(&cfids->laundromat_work, cfids_laundromat_worker);
 	queue_delayed_work(cfid_put_wq, &cfids->laundromat_work,
@@ -757,12 +733,7 @@ void free_cached_dirs(struct cached_fids *cfids)
 
 	spin_lock(&cfids->cfid_list_lock);
 	list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
-		cfid->on_list = false;
-		cfid->is_open = false;
-		list_move(&cfid->entry, &entry);
-	}
-	list_for_each_entry_safe(cfid, q, &cfids->dying, entry) {
-		cfid->on_list = false;
+		invalidate_cfid(cfid, false);
 		cfid->is_open = false;
 		list_move(&cfid->entry, &entry);
 	}
diff --git a/fs/smb/client/cached_dir.h b/fs/smb/client/cached_dir.h
index 5e892d53a67a..e549f019b923 100644
--- a/fs/smb/client/cached_dir.h
+++ b/fs/smb/client/cached_dir.h
@@ -52,12 +52,11 @@ struct cached_fid {
 struct cached_fids {
 	/* Must be held when:
 	 * - accessing the cfids->entries list
-	 * - accessing the cfids->dying list
+	 * - accessing cfids->num_entries
 	 */
 	spinlock_t cfid_list_lock;
 	int num_entries;
 	struct list_head entries;
-	struct list_head dying;
 	struct delayed_work laundromat_work;
 };