v4.19.13 snapshot.
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
new file mode 100644
index 0000000..222bc5d
--- /dev/null
+++ b/fs/cachefiles/interface.c
@@ -0,0 +1,575 @@
+/* FS-Cache interface to CacheFiles
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/slab.h>
+#include <linux/mount.h>
+#include "internal.h"
+
+struct cachefiles_lookup_data {
+ struct cachefiles_xattr *auxdata; /* auxiliary data */
+ char *key; /* key path */
+};
+
+static int cachefiles_attr_changed(struct fscache_object *_object);
+
+/*
+ * allocate an object record for a cookie lookup and prepare the lookup data
+ */
+static struct fscache_object *cachefiles_alloc_object(
+ struct fscache_cache *_cache,
+ struct fscache_cookie *cookie)
+{
+ struct cachefiles_lookup_data *lookup_data;
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ struct cachefiles_xattr *auxdata;
+ unsigned keylen, auxlen;
+ void *buffer, *p;
+ char *key;
+
+ cache = container_of(_cache, struct cachefiles_cache, cache);
+
+ _enter("{%s},%p,", cache->cache.identifier, cookie);
+
+ lookup_data = kmalloc(sizeof(*lookup_data), cachefiles_gfp);
+ if (!lookup_data)
+ goto nomem_lookup_data;
+
+ /* create a new object record and a temporary leaf image */
+ object = kmem_cache_alloc(cachefiles_object_jar, cachefiles_gfp);
+ if (!object)
+ goto nomem_object;
+
+ ASSERTCMP(object->backer, ==, NULL);
+
+ BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
+ atomic_set(&object->usage, 1);
+
+ fscache_object_init(&object->fscache, cookie, &cache->cache);
+
+ object->type = cookie->def->type;
+
+ /* get hold of the raw key
+ * - stick the length on the front and leave space on the back for the
+ * encoder
+ */
+ buffer = kmalloc((2 + 512) + 3, cachefiles_gfp);
+ if (!buffer)
+ goto nomem_buffer;
+
+ keylen = cookie->key_len;
+ if (keylen <= sizeof(cookie->inline_key))
+ p = cookie->inline_key;
+ else
+ p = cookie->key;
+ memcpy(buffer + 2, p, keylen);
+
+ *(uint16_t *)buffer = keylen;
+ ((char *)buffer)[keylen + 2] = 0;
+ ((char *)buffer)[keylen + 3] = 0;
+ ((char *)buffer)[keylen + 4] = 0;
+
+ /* turn the raw key into something that can work with as a filename */
+ key = cachefiles_cook_key(buffer, keylen + 2, object->type);
+ if (!key)
+ goto nomem_key;
+
+ /* get hold of the auxiliary data and prepend the object type */
+ auxdata = buffer;
+ auxlen = cookie->aux_len;
+ if (auxlen) {
+ if (auxlen <= sizeof(cookie->inline_aux))
+ p = cookie->inline_aux;
+ else
+ p = cookie->aux;
+ memcpy(auxdata->data, p, auxlen);
+ }
+
+ auxdata->len = auxlen + 1;
+ auxdata->type = cookie->type;
+
+ lookup_data->auxdata = auxdata;
+ lookup_data->key = key;
+ object->lookup_data = lookup_data;
+
+ _leave(" = %p [%p]", &object->fscache, lookup_data);
+ return &object->fscache;
+
+nomem_key:
+ kfree(buffer);
+nomem_buffer:
+ BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
+ kmem_cache_free(cachefiles_object_jar, object);
+ fscache_object_destroyed(&cache->cache);
+nomem_object:
+ kfree(lookup_data);
+nomem_lookup_data:
+ _leave(" = -ENOMEM");
+ return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * attempt to look up the nominated node in this cache
+ * - return -ETIMEDOUT to be scheduled again
+ */
+static int cachefiles_lookup_object(struct fscache_object *_object)
+{
+ struct cachefiles_lookup_data *lookup_data;
+ struct cachefiles_object *parent, *object;
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ int ret;
+
+ _enter("{OBJ%x}", _object->debug_id);
+
+ cache = container_of(_object->cache, struct cachefiles_cache, cache);
+ parent = container_of(_object->parent,
+ struct cachefiles_object, fscache);
+ object = container_of(_object, struct cachefiles_object, fscache);
+ lookup_data = object->lookup_data;
+
+ ASSERTCMP(lookup_data, !=, NULL);
+
+ /* look up the key, creating any missing bits */
+ cachefiles_begin_secure(cache, &saved_cred);
+ ret = cachefiles_walk_to_object(parent, object,
+ lookup_data->key,
+ lookup_data->auxdata);
+ cachefiles_end_secure(cache, saved_cred);
+
+ /* polish off by setting the attributes of non-index files */
+ if (ret == 0 &&
+ object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX)
+ cachefiles_attr_changed(&object->fscache);
+
+ if (ret < 0 && ret != -ETIMEDOUT) {
+ if (ret != -ENOBUFS)
+ pr_warn("Lookup failed error %d\n", ret);
+ fscache_object_lookup_error(&object->fscache);
+ }
+
+ _leave(" [%d]", ret);
+ return ret;
+}
+
+/*
+ * indication of lookup completion
+ */
+static void cachefiles_lookup_complete(struct fscache_object *_object)
+{
+ struct cachefiles_object *object;
+
+ object = container_of(_object, struct cachefiles_object, fscache);
+
+ _enter("{OBJ%x,%p}", object->fscache.debug_id, object->lookup_data);
+
+ if (object->lookup_data) {
+ kfree(object->lookup_data->key);
+ kfree(object->lookup_data->auxdata);
+ kfree(object->lookup_data);
+ object->lookup_data = NULL;
+ }
+}
+
+/*
+ * increment the usage count on an inode object (may fail if unmounting)
+ */
+static
+struct fscache_object *cachefiles_grab_object(struct fscache_object *_object,
+ enum fscache_obj_ref_trace why)
+{
+ struct cachefiles_object *object =
+ container_of(_object, struct cachefiles_object, fscache);
+ int u;
+
+ _enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage));
+
+#ifdef CACHEFILES_DEBUG_SLAB
+ ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
+#endif
+
+ u = atomic_inc_return(&object->usage);
+ trace_cachefiles_ref(object, _object->cookie,
+ (enum cachefiles_obj_ref_trace)why, u);
+ 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_xattr *auxdata;
+ struct cachefiles_cache *cache;
+ struct fscache_cookie *cookie;
+ const struct cred *saved_cred;
+ const void *aux;
+ unsigned auxlen;
+
+ _enter("{OBJ%x}", _object->debug_id);
+
+ object = container_of(_object, struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache, struct cachefiles_cache,
+ cache);
+
+ if (!fscache_use_cookie(_object)) {
+ _leave(" [relinq]");
+ return;
+ }
+
+ cookie = object->fscache.cookie;
+ auxlen = cookie->aux_len;
+
+ if (!auxlen) {
+ fscache_unuse_cookie(_object);
+ _leave(" [no aux]");
+ return;
+ }
+
+ auxdata = kmalloc(2 + auxlen + 3, cachefiles_gfp);
+ if (!auxdata) {
+ fscache_unuse_cookie(_object);
+ _leave(" [nomem]");
+ return;
+ }
+
+ aux = (auxlen <= sizeof(cookie->inline_aux)) ?
+ cookie->inline_aux : cookie->aux;
+
+ memcpy(auxdata->data, aux, auxlen);
+ fscache_unuse_cookie(_object);
+
+ auxdata->len = auxlen + 1;
+ auxdata->type = cookie->type;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ cachefiles_update_object_xattr(object, auxdata);
+ cachefiles_end_secure(cache, saved_cred);
+ kfree(auxdata);
+ _leave("");
+}
+
+/*
+ * discard the resources pinned by an object and effect retirement if
+ * requested
+ */
+static void cachefiles_drop_object(struct fscache_object *_object)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ struct inode *inode;
+ blkcnt_t i_blocks = 0;
+
+ ASSERT(_object);
+
+ object = container_of(_object, struct cachefiles_object, fscache);
+
+ _enter("{OBJ%x,%d}",
+ object->fscache.debug_id, atomic_read(&object->usage));
+
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+#ifdef CACHEFILES_DEBUG_SLAB
+ ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
+#endif
+
+ /* We need to tidy the object up if we did in fact manage to open it.
+ * It's possible for us to get here before the object is fully
+ * initialised if the parent goes away or the object gets retired
+ * before we set it up.
+ */
+ if (object->dentry) {
+ /* delete retired objects */
+ if (test_bit(FSCACHE_OBJECT_RETIRED, &object->fscache.flags) &&
+ _object != cache->cache.fsdef
+ ) {
+ _debug("- retire object OBJ%x", object->fscache.debug_id);
+ inode = d_backing_inode(object->dentry);
+ if (inode)
+ i_blocks = inode->i_blocks;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ cachefiles_delete_object(cache, object);
+ cachefiles_end_secure(cache, saved_cred);
+ }
+
+ /* close the filesystem stuff attached to the object */
+ if (object->backer != object->dentry)
+ dput(object->backer);
+ object->backer = NULL;
+ }
+
+ /* note that the object is now inactive */
+ if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags))
+ cachefiles_mark_object_inactive(cache, object, i_blocks);
+
+ dput(object->dentry);
+ object->dentry = NULL;
+
+ _leave("");
+}
+
+/*
+ * dispose of a reference to an object
+ */
+static void cachefiles_put_object(struct fscache_object *_object,
+ enum fscache_obj_ref_trace why)
+{
+ struct cachefiles_object *object;
+ struct fscache_cache *cache;
+ int u;
+
+ ASSERT(_object);
+
+ object = container_of(_object, struct cachefiles_object, fscache);
+
+ _enter("{OBJ%x,%d}",
+ object->fscache.debug_id, atomic_read(&object->usage));
+
+#ifdef CACHEFILES_DEBUG_SLAB
+ ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
+#endif
+
+ ASSERTIFCMP(object->fscache.parent,
+ object->fscache.parent->n_children, >, 0);
+
+ u = atomic_dec_return(&object->usage);
+ trace_cachefiles_ref(object, _object->cookie,
+ (enum cachefiles_obj_ref_trace)why, u);
+ ASSERTCMP(u, !=, -1);
+ if (u == 0) {
+ _debug("- kill object OBJ%x", object->fscache.debug_id);
+
+ ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
+ ASSERTCMP(object->fscache.parent, ==, NULL);
+ ASSERTCMP(object->backer, ==, NULL);
+ ASSERTCMP(object->dentry, ==, NULL);
+ ASSERTCMP(object->fscache.n_ops, ==, 0);
+ ASSERTCMP(object->fscache.n_children, ==, 0);
+
+ if (object->lookup_data) {
+ kfree(object->lookup_data->key);
+ kfree(object->lookup_data->auxdata);
+ kfree(object->lookup_data);
+ object->lookup_data = NULL;
+ }
+
+ cache = object->fscache.cache;
+ fscache_object_destroy(&object->fscache);
+ kmem_cache_free(cachefiles_object_jar, object);
+ fscache_object_destroyed(cache);
+ }
+
+ _leave("");
+}
+
+/*
+ * sync a cache
+ */
+static void cachefiles_sync_cache(struct fscache_cache *_cache)
+{
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ int ret;
+
+ _enter("%p", _cache);
+
+ cache = container_of(_cache, struct cachefiles_cache, cache);
+
+ /* make sure all pages pinned by operations on behalf of the netfs are
+ * written to disc */
+ cachefiles_begin_secure(cache, &saved_cred);
+ down_read(&cache->mnt->mnt_sb->s_umount);
+ ret = sync_filesystem(cache->mnt->mnt_sb);
+ up_read(&cache->mnt->mnt_sb->s_umount);
+ cachefiles_end_secure(cache, saved_cred);
+
+ if (ret == -EIO)
+ cachefiles_io_error(cache,
+ "Attempt to sync backing fs superblock"
+ " returned error %d",
+ ret);
+}
+
+/*
+ * check if the backing cache is updated to FS-Cache
+ * - called by FS-Cache when evaluates if need to invalidate the cache
+ */
+static int cachefiles_check_consistency(struct fscache_operation *op)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ int ret;
+
+ _enter("{OBJ%x}", op->object->debug_id);
+
+ object = container_of(op->object, struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ ret = cachefiles_check_auxdata(object);
+ cachefiles_end_secure(cache, saved_cred);
+
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * notification the attributes on an object have changed
+ * - called with reads/writes excluded by FS-Cache
+ */
+static int cachefiles_attr_changed(struct fscache_object *_object)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ struct iattr newattrs;
+ uint64_t ni_size;
+ loff_t oi_size;
+ int ret;
+
+ ni_size = _object->store_limit_l;
+
+ _enter("{OBJ%x},[%llu]",
+ _object->debug_id, (unsigned long long) ni_size);
+
+ object = container_of(_object, struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+ if (ni_size == object->i_size)
+ return 0;
+
+ if (!object->backer)
+ return -ENOBUFS;
+
+ ASSERT(d_is_reg(object->backer));
+
+ fscache_set_store_limit(&object->fscache, ni_size);
+
+ oi_size = i_size_read(d_backing_inode(object->backer));
+ if (oi_size == ni_size)
+ return 0;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ inode_lock(d_inode(object->backer));
+
+ /* if there's an extension to a partial page at the end of the backing
+ * file, we need to discard the partial page so that we pick up new
+ * data after it */
+ if (oi_size & ~PAGE_MASK && ni_size > oi_size) {
+ _debug("discard tail %llx", oi_size);
+ newattrs.ia_valid = ATTR_SIZE;
+ newattrs.ia_size = oi_size & PAGE_MASK;
+ ret = notify_change(object->backer, &newattrs, NULL);
+ if (ret < 0)
+ goto truncate_failed;
+ }
+
+ newattrs.ia_valid = ATTR_SIZE;
+ newattrs.ia_size = ni_size;
+ ret = notify_change(object->backer, &newattrs, NULL);
+
+truncate_failed:
+ inode_unlock(d_inode(object->backer));
+ cachefiles_end_secure(cache, saved_cred);
+
+ if (ret == -EIO) {
+ fscache_set_store_limit(&object->fscache, 0);
+ cachefiles_io_error_obj(object, "Size set failed");
+ ret = -ENOBUFS;
+ }
+
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * Invalidate an object
+ */
+static void cachefiles_invalidate_object(struct fscache_operation *op)
+{
+ struct cachefiles_object *object;
+ struct cachefiles_cache *cache;
+ const struct cred *saved_cred;
+ struct path path;
+ uint64_t ni_size;
+ int ret;
+
+ object = container_of(op->object, struct cachefiles_object, fscache);
+ cache = container_of(object->fscache.cache,
+ struct cachefiles_cache, cache);
+
+ ni_size = op->object->store_limit_l;
+
+ _enter("{OBJ%x},[%llu]",
+ op->object->debug_id, (unsigned long long)ni_size);
+
+ if (object->backer) {
+ ASSERT(d_is_reg(object->backer));
+
+ fscache_set_store_limit(&object->fscache, ni_size);
+
+ path.dentry = object->backer;
+ path.mnt = cache->mnt;
+
+ cachefiles_begin_secure(cache, &saved_cred);
+ ret = vfs_truncate(&path, 0);
+ if (ret == 0)
+ ret = vfs_truncate(&path, ni_size);
+ cachefiles_end_secure(cache, saved_cred);
+
+ if (ret != 0) {
+ fscache_set_store_limit(&object->fscache, 0);
+ if (ret == -EIO)
+ cachefiles_io_error_obj(object,
+ "Invalidate failed");
+ }
+ }
+
+ fscache_op_complete(op, true);
+ _leave("");
+}
+
+/*
+ * dissociate a cache from all the pages it was backing
+ */
+static void cachefiles_dissociate_pages(struct fscache_cache *cache)
+{
+ _enter("");
+}
+
+const struct fscache_cache_ops cachefiles_cache_ops = {
+ .name = "cachefiles",
+ .alloc_object = cachefiles_alloc_object,
+ .lookup_object = cachefiles_lookup_object,
+ .lookup_complete = cachefiles_lookup_complete,
+ .grab_object = cachefiles_grab_object,
+ .update_object = cachefiles_update_object,
+ .invalidate_object = cachefiles_invalidate_object,
+ .drop_object = cachefiles_drop_object,
+ .put_object = cachefiles_put_object,
+ .sync_cache = cachefiles_sync_cache,
+ .attr_changed = cachefiles_attr_changed,
+ .read_or_alloc_page = cachefiles_read_or_alloc_page,
+ .read_or_alloc_pages = cachefiles_read_or_alloc_pages,
+ .allocate_page = cachefiles_allocate_page,
+ .allocate_pages = cachefiles_allocate_pages,
+ .write_page = cachefiles_write_page,
+ .uncache_page = cachefiles_uncache_page,
+ .dissociate_pages = cachefiles_dissociate_pages,
+ .check_consistency = cachefiles_check_consistency,
+};