| 1 | |
| 2 | |
| 3 | *
|
| 4 | * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
|
| 5 | * Written by David Howells ([email protected])
|
| 6 |
|
| 7 |
|
| 8 | #include <linux/fs.h>
|
| 9 | #include <linux/slab.h>
|
| 10 | #include <linux/namei.h>
|
| 11 | #include "internal.h"
|
| 12 | #include <trace/events/fscache.h>
|
| 13 |
|
| 14 | |
| 15 | * Allocate and set up a volume representation. We make sure all the fanout
|
| 16 | * directories are created and pinned.
|
| 17 |
|
| 18 | void cachefiles_acquire_volume(struct fscache_volume *vcookie)
|
| 19 | {
|
| 20 | struct cachefiles_volume *volume;
|
| 21 | struct cachefiles_cache *cache = vcookie->cache->cache_priv;
|
| 22 | const struct cred *saved_cred;
|
| 23 | struct dentry *vdentry, *fan;
|
| 24 | size_t len;
|
| 25 | char *name;
|
| 26 | bool is_new = false;
|
| 27 | int ret, n_accesses, i;
|
| 28 |
|
| 29 | _enter("");
|
| 30 |
|
| 31 | volume = kzalloc_obj(struct cachefiles_volume);
|
| 32 | if (!volume)
|
| 33 | return;
|
| 34 | volume->vcookie = vcookie;
|
| 35 | volume->cache = cache;
|
| 36 | INIT_LIST_HEAD(&volume->cache_link);
|
| 37 |
|
| 38 | cachefiles_begin_secure(cache, &saved_cred);
|
| 39 |
|
| 40 | len = vcookie->key[0];
|
| 41 | name = kmalloc(len + 3, GFP_NOFS);
|
| 42 | if (!name)
|
| 43 | goto error_vol;
|
| 44 | name[0] = 'I';
|
| 45 | memcpy(name + 1, vcookie->key + 1, len);
|
| 46 | name[len + 1] = 0;
|
| 47 |
|
| 48 | retry:
|
| 49 | vdentry = cachefiles_get_directory(cache, cache->store, name, &is_new);
|
| 50 | if (IS_ERR(vdentry))
|
| 51 | goto error_name;
|
| 52 | volume->dentry = vdentry;
|
| 53 |
|
| 54 | if (is_new) {
|
| 55 | if (!cachefiles_set_volume_xattr(volume))
|
| 56 | goto error_dir;
|
| 57 | } else {
|
| 58 | ret = cachefiles_check_volume_xattr(volume);
|
| 59 | if (ret < 0) {
|
| 60 | if (ret != -ESTALE)
|
| 61 | goto error_dir;
|
| 62 | vdentry = start_removing_dentry(cache->store, vdentry);
|
| 63 | if (!IS_ERR(vdentry))
|
| 64 | cachefiles_bury_object(cache, NULL, cache->store,
|
| 65 | vdentry,
|
| 66 | FSCACHE_VOLUME_IS_WEIRD);
|
| 67 | cachefiles_put_directory(volume->dentry);
|
| 68 | cond_resched();
|
| 69 | goto retry;
|
| 70 | }
|
| 71 | }
|
| 72 |
|
| 73 | for (i = 0; i < 256; i++) {
|
| 74 | sprintf(name, "@%02x", i);
|
| 75 | fan = cachefiles_get_directory(cache, vdentry, name, NULL);
|
| 76 | if (IS_ERR(fan))
|
| 77 | goto error_fan;
|
| 78 | volume->fanout[i] = fan;
|
| 79 | }
|
| 80 |
|
| 81 | cachefiles_end_secure(cache, saved_cred);
|
| 82 |
|
| 83 | vcookie->cache_priv = volume;
|
| 84 | n_accesses = atomic_inc_return(&vcookie->n_accesses);
|
| 85 | trace_fscache_access_volume(vcookie->debug_id, 0,
|
| 86 | refcount_read(&vcookie->ref),
|
| 87 | n_accesses, fscache_access_cache_pin);
|
| 88 |
|
| 89 | spin_lock(&cache->object_list_lock);
|
| 90 | list_add(&volume->cache_link, &volume->cache->volumes);
|
| 91 | spin_unlock(&cache->object_list_lock);
|
| 92 |
|
| 93 | kfree(name);
|
| 94 | return;
|
| 95 |
|
| 96 | error_fan:
|
| 97 | for (i = 0; i < 256; i++)
|
| 98 | cachefiles_put_directory(volume->fanout[i]);
|
| 99 | error_dir:
|
| 100 | cachefiles_put_directory(volume->dentry);
|
| 101 | error_name:
|
| 102 | kfree(name);
|
| 103 | error_vol:
|
| 104 | kfree(volume);
|
| 105 | cachefiles_end_secure(cache, saved_cred);
|
| 106 | }
|
| 107 |
|
| 108 | |
| 109 | * Release a volume representation.
|
| 110 |
|
| 111 | static void __cachefiles_free_volume(struct cachefiles_volume *volume)
|
| 112 | {
|
| 113 | int i;
|
| 114 |
|
| 115 | _enter("");
|
| 116 |
|
| 117 | volume->vcookie->cache_priv = NULL;
|
| 118 |
|
| 119 | for (i = 0; i < 256; i++)
|
| 120 | cachefiles_put_directory(volume->fanout[i]);
|
| 121 | cachefiles_put_directory(volume->dentry);
|
| 122 | kfree(volume);
|
| 123 | }
|
| 124 |
|
| 125 | void cachefiles_free_volume(struct fscache_volume *vcookie)
|
| 126 | {
|
| 127 | struct cachefiles_volume *volume = vcookie->cache_priv;
|
| 128 |
|
| 129 | if (volume) {
|
| 130 | spin_lock(&volume->cache->object_list_lock);
|
| 131 | list_del_init(&volume->cache_link);
|
| 132 | spin_unlock(&volume->cache->object_list_lock);
|
| 133 | __cachefiles_free_volume(volume);
|
| 134 | }
|
| 135 | }
|
| 136 |
|
| 137 | void cachefiles_withdraw_volume(struct cachefiles_volume *volume)
|
| 138 | {
|
| 139 | cachefiles_set_volume_xattr(volume);
|
| 140 | __cachefiles_free_volume(volume);
|
| 141 | }
|