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fe2140e2 DH |
1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* Volume handling. | |
3 | * | |
4 | * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. | |
5 | * Written by David Howells (dhowells@redhat.com) | |
6 | */ | |
7 | ||
8 | #include <linux/fs.h> | |
9 | #include <linux/slab.h> | |
10 | #include "internal.h" | |
11 | #include <trace/events/fscache.h> | |
12 | ||
13 | /* | |
14 | * Allocate and set up a volume representation. We make sure all the fanout | |
15 | * directories are created and pinned. | |
16 | */ | |
17 | void cachefiles_acquire_volume(struct fscache_volume *vcookie) | |
18 | { | |
19 | struct cachefiles_volume *volume; | |
20 | struct cachefiles_cache *cache = vcookie->cache->cache_priv; | |
21 | const struct cred *saved_cred; | |
22 | struct dentry *vdentry, *fan; | |
23 | size_t len; | |
24 | char *name; | |
32e15003 DH |
25 | bool is_new = false; |
26 | int ret, n_accesses, i; | |
fe2140e2 DH |
27 | |
28 | _enter(""); | |
29 | ||
30 | volume = kzalloc(sizeof(struct cachefiles_volume), GFP_KERNEL); | |
31 | if (!volume) | |
32 | return; | |
33 | volume->vcookie = vcookie; | |
34 | volume->cache = cache; | |
35 | INIT_LIST_HEAD(&volume->cache_link); | |
36 | ||
37 | cachefiles_begin_secure(cache, &saved_cred); | |
38 | ||
39 | len = vcookie->key[0]; | |
40 | name = kmalloc(len + 3, GFP_NOFS); | |
41 | if (!name) | |
42 | goto error_vol; | |
43 | name[0] = 'I'; | |
44 | memcpy(name + 1, vcookie->key + 1, len); | |
45 | name[len + 1] = 0; | |
46 | ||
32e15003 DH |
47 | retry: |
48 | vdentry = cachefiles_get_directory(cache, cache->store, name, &is_new); | |
fe2140e2 DH |
49 | if (IS_ERR(vdentry)) |
50 | goto error_name; | |
51 | volume->dentry = vdentry; | |
52 | ||
32e15003 DH |
53 | if (is_new) { |
54 | if (!cachefiles_set_volume_xattr(volume)) | |
55 | goto error_dir; | |
56 | } else { | |
57 | ret = cachefiles_check_volume_xattr(volume); | |
58 | if (ret < 0) { | |
59 | if (ret != -ESTALE) | |
60 | goto error_dir; | |
61 | inode_lock_nested(d_inode(cache->store), I_MUTEX_PARENT); | |
62 | cachefiles_bury_object(cache, NULL, cache->store, vdentry, | |
63 | FSCACHE_VOLUME_IS_WEIRD); | |
64 | cachefiles_put_directory(volume->dentry); | |
65 | cond_resched(); | |
66 | goto retry; | |
67 | } | |
68 | } | |
69 | ||
fe2140e2 DH |
70 | for (i = 0; i < 256; i++) { |
71 | sprintf(name, "@%02x", i); | |
72 | fan = cachefiles_get_directory(cache, vdentry, name, NULL); | |
73 | if (IS_ERR(fan)) | |
74 | goto error_fan; | |
75 | volume->fanout[i] = fan; | |
76 | } | |
77 | ||
78 | cachefiles_end_secure(cache, saved_cred); | |
79 | ||
80 | vcookie->cache_priv = volume; | |
81 | n_accesses = atomic_inc_return(&vcookie->n_accesses); /* Stop wakeups on dec-to-0 */ | |
82 | trace_fscache_access_volume(vcookie->debug_id, 0, | |
83 | refcount_read(&vcookie->ref), | |
84 | n_accesses, fscache_access_cache_pin); | |
85 | ||
86 | spin_lock(&cache->object_list_lock); | |
87 | list_add(&volume->cache_link, &volume->cache->volumes); | |
88 | spin_unlock(&cache->object_list_lock); | |
89 | ||
90 | kfree(name); | |
91 | return; | |
92 | ||
93 | error_fan: | |
94 | for (i = 0; i < 256; i++) | |
95 | cachefiles_put_directory(volume->fanout[i]); | |
32e15003 | 96 | error_dir: |
fe2140e2 DH |
97 | cachefiles_put_directory(volume->dentry); |
98 | error_name: | |
99 | kfree(name); | |
100 | error_vol: | |
101 | kfree(volume); | |
102 | cachefiles_end_secure(cache, saved_cred); | |
103 | } | |
104 | ||
105 | /* | |
106 | * Release a volume representation. | |
107 | */ | |
108 | static void __cachefiles_free_volume(struct cachefiles_volume *volume) | |
109 | { | |
110 | int i; | |
111 | ||
112 | _enter(""); | |
113 | ||
114 | volume->vcookie->cache_priv = NULL; | |
115 | ||
116 | for (i = 0; i < 256; i++) | |
117 | cachefiles_put_directory(volume->fanout[i]); | |
118 | cachefiles_put_directory(volume->dentry); | |
119 | kfree(volume); | |
120 | } | |
121 | ||
122 | void cachefiles_free_volume(struct fscache_volume *vcookie) | |
123 | { | |
124 | struct cachefiles_volume *volume = vcookie->cache_priv; | |
125 | ||
126 | if (volume) { | |
127 | spin_lock(&volume->cache->object_list_lock); | |
128 | list_del_init(&volume->cache_link); | |
129 | spin_unlock(&volume->cache->object_list_lock); | |
130 | __cachefiles_free_volume(volume); | |
131 | } | |
132 | } | |
133 | ||
134 | void cachefiles_withdraw_volume(struct cachefiles_volume *volume) | |
135 | { | |
136 | fscache_withdraw_volume(volume->vcookie); | |
32e15003 | 137 | cachefiles_set_volume_xattr(volume); |
fe2140e2 DH |
138 | __cachefiles_free_volume(volume); |
139 | } |