[RFC PATCH 55/76] fscache: Remove the update operation

[David Howells]

Remove the cache-side of the object update operation as it doesn't
serialise with other setattr, O_TRUNC and write operations.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

 fs/cachefiles/interface.c     |   59 -----------------------------------------
 fs/fscache/internal.h         |    2 -
 fs/fscache/obj.c              |   14 ----------
 fs/fscache/stats.c            |    6 +---
 include/linux/fscache-cache.h |    2 -
 5 files changed, 2 insertions(+), 81 deletions(-)

diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index aca08e4227b9..3609ff2fb491 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -150,64 +150,6 @@ struct fscache_object *cachefiles_grab_object(struct fscache_object *_object,
 	return &object->fscache;
 }
 
-/*
- * update the auxiliary data for an object object on disk
- */
-static void cachefiles_update_object(struct fscache_object *_object)
-{
-	struct cachefiles_object *object;
-	struct cachefiles_cache *cache;
-	const struct cred *saved_cred;
-	struct inode *inode;
-	loff_t object_size, i_size;
-	int ret;
-
-	_enter("{OBJ%x}", _object->debug_id);
-
-	object = container_of(_object, struct cachefiles_object, fscache);
-	cache = container_of(object->fscache.cache, struct cachefiles_cache,
-			     cache);
-
-	cachefiles_begin_secure(cache, &saved_cred);
-
-	object_size = object->fscache.cookie->object_size;
-	inode = d_inode(object->dentry);
-	i_size = i_size_read(inode);
-	if (i_size > object_size) {
-		struct path path = {
-			.mnt	= cache->mnt,
-			.dentry	= object->dentry
-		};
-		_debug("trunc %llx -> %llx", i_size, object_size);
-		trace_cachefiles_trunc(object, inode, i_size, object_size);
-		ret = vfs_truncate(&path, object_size);
-		if (ret < 0) {
-			cachefiles_io_error_obj(object, "Trunc-to-size failed");
-			cachefiles_remove_object_xattr(cache, object->dentry);
-			goto out;
-		}
-
-		object_size = round_up(object_size, CACHEFILES_DIO_BLOCK_SIZE);
-		i_size = i_size_read(inode);
-		_debug("trunc %llx -> %llx", i_size, object_size);
-		if (i_size < object_size) {
-			trace_cachefiles_trunc(object, inode, i_size, object_size);
-			ret = vfs_truncate(&path, object_size);
-			if (ret < 0) {
-				cachefiles_io_error_obj(object, "Trunc-to-dio-size failed");
-				cachefiles_remove_object_xattr(cache, object->dentry);
-				goto out;
-			}
-		}
-	}
-
-	cachefiles_set_object_xattr(object);
-
-out:
-	cachefiles_end_secure(cache, saved_cred);
-	_leave("");
-}
-
 /*
  * Shorten the backing object to discard any dirty data and free up
  * any unused granules.
@@ -681,7 +623,6 @@ const struct fscache_cache_ops cachefiles_cache_ops = {
 	.lookup_object		= cachefiles_lookup_object,
 	.free_lookup_data	= cachefiles_free_lookup_data,
 	.grab_object		= cachefiles_grab_object,
-	.update_object		= cachefiles_update_object,
 	.resize_object		= cachefiles_resize_object,
 	.invalidate_object	= cachefiles_invalidate_object,
 	.drop_object		= cachefiles_drop_object,
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
index ff193f61a4c5..510f166103bf 100644
--- a/fs/fscache/internal.h
+++ b/fs/fscache/internal.h
@@ -189,7 +189,6 @@ extern atomic_t fscache_n_acquires_oom;
 extern atomic_t fscache_n_invalidates;
 
 extern atomic_t fscache_n_updates;
-extern atomic_t fscache_n_updates_run;
 
 extern atomic_t fscache_n_relinquishes;
 extern atomic_t fscache_n_relinquishes_retire;
@@ -214,7 +213,6 @@ extern atomic_t fscache_n_cop_alloc_object;
 extern atomic_t fscache_n_cop_lookup_object;
 extern atomic_t fscache_n_cop_create_object;
 extern atomic_t fscache_n_cop_invalidate_object;
-extern atomic_t fscache_n_cop_update_object;
 extern atomic_t fscache_n_cop_drop_object;
 extern atomic_t fscache_n_cop_put_object;
 extern atomic_t fscache_n_cop_sync_cache;
diff --git a/fs/fscache/obj.c b/fs/fscache/obj.c
index a36de6af2182..2b0c99095a42 100644
--- a/fs/fscache/obj.c
+++ b/fs/fscache/obj.c
@@ -54,14 +54,6 @@ static int fscache_do_create_object(struct fscache_object *object, void *data)
 	return ret;
 }
 
-static void fscache_do_update_object(struct fscache_object *object)
-{
-	fscache_stat(&fscache_n_updates_run);
-	fscache_stat(&fscache_n_cop_update_object);
-	object->cache->ops->update_object(object);
-	fscache_stat_d(&fscache_n_cop_update_object);
-}
-
 static void fscache_do_drop_object(struct fscache_cache *cache,
 				   struct fscache_object *object,
 				   bool invalidate)
@@ -291,12 +283,6 @@ void fscache_drop_object(struct fscache_cookie *cookie,
 	_enter("{o=%08x,%d},%u",
 	       object->debug_id, object->n_children, invalidate);
 
-	if (!invalidate &&
-	    test_bit(FSCACHE_OBJECT_NEEDS_UPDATE, &object->flags)) {
-		_debug("final update");
-		fscache_do_update_object(object);
-	}
-
 	spin_lock(&cache->object_list_lock);
 	list_del_init(&object->cache_link);
 	spin_unlock(&cache->object_list_lock);
diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c
index 2a2df9d1649e..350e65870dff 100644
--- a/fs/fscache/stats.c
+++ b/fs/fscache/stats.c
@@ -102,9 +102,8 @@ static int fscache_stats_show(struct seq_file *m, void *v)
 	seq_printf(m, "Invals : n=%u\n",
 		   atomic_read(&fscache_n_invalidates));
 
-	seq_printf(m, "Updates: n=%u nul=%u rsz=%u rsn=%u\n",
+	seq_printf(m, "Updates: n=%u rsz=%u rsn=%u\n",
 		   atomic_read(&fscache_n_updates),
-		   atomic_read(&fscache_n_updates_run),
 		   atomic_read(&fscache_n_resizes),
 		   atomic_read(&fscache_n_resizes_null));
 
@@ -115,9 +114,8 @@ static int fscache_stats_show(struct seq_file *m, void *v)
 	seq_printf(m, "CacheOp: alo=%d luo=%d\n",
 		   atomic_read(&fscache_n_cop_alloc_object),
 		   atomic_read(&fscache_n_cop_lookup_object));
-	seq_printf(m, "CacheOp: inv=%d upo=%d dro=%d pto=%d atc=%d syn=%d\n",
+	seq_printf(m, "CacheOp: inv=%d dro=%d pto=%d atc=%d syn=%d\n",
 		   atomic_read(&fscache_n_cop_invalidate_object),
-		   atomic_read(&fscache_n_cop_update_object),
 		   atomic_read(&fscache_n_cop_drop_object),
 		   atomic_read(&fscache_n_cop_put_object),
 		   atomic_read(&fscache_n_cop_attr_changed),
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index 958fa899917d..74a09738c899 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -115,8 +115,6 @@ struct fscache_cache_ops {
 	/* unpin an object in the cache */
 	void (*unpin_object)(struct fscache_object *object);
 
-	/* store the updated auxiliary data on an object */
-	void (*update_object)(struct fscache_object *object);
 	/* Change the size of a data object */
 	void (*resize_object)(struct fscache_object *object, loff_t new_size);