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authorDavid Howells <dhowells@redhat.com>2021-11-17 16:22:21 +0000
committerDavid Howells <dhowells@redhat.com>2022-01-07 13:42:08 +0000
commitdf98e87f2091774c377ddfaedfe64bd90ed4bdca (patch)
tree626bfd7ea0af245966ca301cc7b1c1f28c38f9de /fs/cachefiles
parent13871bad1ef7f41947c816a9e342aa9fa8643c5e (diff)
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cachefiles: Implement object lifecycle funcs
Implement allocate, get, see and put functions for the cachefiles_object struct. The members of the struct we're going to need are also added. Additionally, implement a lifecycle tracepoint. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819639457.215744.4600093239395728232.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906939569.143852.3594314410666551982.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967148857.1823006.6332962598220464364.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021547762.640689.8422781599594931000.stgit@warthog.procyon.org.uk/ # v4
Diffstat (limited to 'fs/cachefiles')
-rw-r--r--fs/cachefiles/interface.c86
-rw-r--r--fs/cachefiles/internal.h35
-rw-r--r--fs/cachefiles/main.c16
3 files changed, 135 insertions, 2 deletions
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index 1793e46bd3e7..68bb7b6c4945 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -13,6 +13,92 @@
#include <trace/events/fscache.h>
#include "internal.h"
+static atomic_t cachefiles_object_debug_id;
+
+/*
+ * Allocate a cache object record.
+ */
+static
+struct cachefiles_object *cachefiles_alloc_object(struct fscache_cookie *cookie)
+{
+ struct fscache_volume *vcookie = cookie->volume;
+ struct cachefiles_volume *volume = vcookie->cache_priv;
+ struct cachefiles_object *object;
+
+ _enter("{%s},%x,", vcookie->key, cookie->debug_id);
+
+ object = kmem_cache_zalloc(cachefiles_object_jar, GFP_KERNEL);
+ if (!object)
+ return NULL;
+
+ refcount_set(&object->ref, 1);
+
+ spin_lock_init(&object->lock);
+ INIT_LIST_HEAD(&object->cache_link);
+ object->volume = volume;
+ object->debug_id = atomic_inc_return(&cachefiles_object_debug_id);
+ object->cookie = fscache_get_cookie(cookie, fscache_cookie_get_attach_object);
+
+ fscache_count_object(vcookie->cache);
+ trace_cachefiles_ref(object->debug_id, cookie->debug_id, 1,
+ cachefiles_obj_new);
+ return object;
+}
+
+/*
+ * Note that an object has been seen.
+ */
+void cachefiles_see_object(struct cachefiles_object *object,
+ enum cachefiles_obj_ref_trace why)
+{
+ trace_cachefiles_ref(object->debug_id, object->cookie->debug_id,
+ refcount_read(&object->ref), why);
+}
+
+/*
+ * Increment the usage count on an object;
+ */
+struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
+ enum cachefiles_obj_ref_trace why)
+{
+ int r;
+
+ __refcount_inc(&object->ref, &r);
+ trace_cachefiles_ref(object->debug_id, object->cookie->debug_id, r, why);
+ return object;
+}
+
+/*
+ * dispose of a reference to an object
+ */
+void cachefiles_put_object(struct cachefiles_object *object,
+ enum cachefiles_obj_ref_trace why)
+{
+ unsigned int object_debug_id = object->debug_id;
+ unsigned int cookie_debug_id = object->cookie->debug_id;
+ struct fscache_cache *cache;
+ bool done;
+ int r;
+
+ done = __refcount_dec_and_test(&object->ref, &r);
+ trace_cachefiles_ref(object_debug_id, cookie_debug_id, r, why);
+ if (done) {
+ _debug("- kill object OBJ%x", object_debug_id);
+
+ ASSERTCMP(object->file, ==, NULL);
+
+ kfree(object->d_name);
+
+ cache = object->volume->cache->cache;
+ fscache_put_cookie(object->cookie, fscache_cookie_put_object);
+ object->cookie = NULL;
+ kmem_cache_free(cachefiles_object_jar, object);
+ fscache_uncount_object(cache);
+ }
+
+ _leave("");
+}
+
const struct fscache_cache_ops cachefiles_cache_ops = {
.name = "cachefiles",
.acquire_volume = cachefiles_acquire_volume,
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index ab0e9307be7b..8763ee4a0df2 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -19,6 +19,16 @@
struct cachefiles_cache;
struct cachefiles_object;
+enum cachefiles_content {
+ /* These values are saved on disk */
+ CACHEFILES_CONTENT_NO_DATA = 0, /* No content stored */
+ CACHEFILES_CONTENT_SINGLE = 1, /* Content is monolithic, all is present */
+ CACHEFILES_CONTENT_ALL = 2, /* Content is all present, no map */
+ CACHEFILES_CONTENT_BACKFS_MAP = 3, /* Content is piecemeal, mapped through backing fs */
+ CACHEFILES_CONTENT_DIRTY = 4, /* Content is dirty (only seen on disk) */
+ nr__cachefiles_content
+};
+
/*
* Cached volume representation.
*/
@@ -31,10 +41,20 @@ struct cachefiles_volume {
};
/*
- * Data file records.
+ * Backing file state.
*/
struct cachefiles_object {
- int debug_id; /* debugging ID */
+ struct fscache_cookie *cookie; /* Netfs data storage object cookie */
+ struct cachefiles_volume *volume; /* Cache volume that holds this object */
+ struct list_head cache_link; /* Link in cache->*_list */
+ struct file *file; /* The file representing this object */
+ char *d_name; /* Backing file name */
+ int debug_id;
+ spinlock_t lock;
+ refcount_t ref;
+ u8 d_name_len; /* Length of filename */
+ enum cachefiles_content content_info:8; /* Info about content presence */
+ unsigned long flags;
};
/*
@@ -146,6 +166,17 @@ static inline int cachefiles_inject_remove_error(void)
* interface.c
*/
extern const struct fscache_cache_ops cachefiles_cache_ops;
+extern void cachefiles_see_object(struct cachefiles_object *object,
+ enum cachefiles_obj_ref_trace why);
+extern struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
+ enum cachefiles_obj_ref_trace why);
+extern void cachefiles_put_object(struct cachefiles_object *object,
+ enum cachefiles_obj_ref_trace why);
+
+/*
+ * main.c
+ */
+extern struct kmem_cache *cachefiles_object_jar;
/*
* namei.c
diff --git a/fs/cachefiles/main.c b/fs/cachefiles/main.c
index 533e3067d80f..3f369c6f816d 100644
--- a/fs/cachefiles/main.c
+++ b/fs/cachefiles/main.c
@@ -31,6 +31,8 @@ MODULE_DESCRIPTION("Mounted-filesystem based cache");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");
+struct kmem_cache *cachefiles_object_jar;
+
static struct miscdevice cachefiles_dev = {
.minor = MISC_DYNAMIC_MINOR,
.name = "cachefiles",
@@ -51,9 +53,22 @@ static int __init cachefiles_init(void)
if (ret < 0)
goto error_dev;
+ /* create an object jar */
+ ret = -ENOMEM;
+ cachefiles_object_jar =
+ kmem_cache_create("cachefiles_object_jar",
+ sizeof(struct cachefiles_object),
+ 0, SLAB_HWCACHE_ALIGN, NULL);
+ if (!cachefiles_object_jar) {
+ pr_notice("Failed to allocate an object jar\n");
+ goto error_object_jar;
+ }
+
pr_info("Loaded\n");
return 0;
+error_object_jar:
+ misc_deregister(&cachefiles_dev);
error_dev:
cachefiles_unregister_error_injection();
error_einj:
@@ -70,6 +85,7 @@ static void __exit cachefiles_exit(void)
{
pr_info("Unloading\n");
+ kmem_cache_destroy(cachefiles_object_jar);
misc_deregister(&cachefiles_dev);
cachefiles_unregister_error_injection();
}