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

From: David Howells
Date: Fri Nov 20 2020 - 10:14:45 EST


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);