Merge tag 'sched-urgent-2020-11-15' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6-microblaze.git] / fs / btrfs / props.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2014 Filipe David Borba Manana <fdmanana@gmail.com>
4  */
5
6 #include <linux/hashtable.h>
7 #include "props.h"
8 #include "btrfs_inode.h"
9 #include "transaction.h"
10 #include "ctree.h"
11 #include "xattr.h"
12 #include "compression.h"
13
14 #define BTRFS_PROP_HANDLERS_HT_BITS 8
15 static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
16
17 struct prop_handler {
18         struct hlist_node node;
19         const char *xattr_name;
20         int (*validate)(const char *value, size_t len);
21         int (*apply)(struct inode *inode, const char *value, size_t len);
22         const char *(*extract)(struct inode *inode);
23         int inheritable;
24 };
25
26 static const struct hlist_head *find_prop_handlers_by_hash(const u64 hash)
27 {
28         struct hlist_head *h;
29
30         h = &prop_handlers_ht[hash_min(hash, BTRFS_PROP_HANDLERS_HT_BITS)];
31         if (hlist_empty(h))
32                 return NULL;
33
34         return h;
35 }
36
37 static const struct prop_handler *
38 find_prop_handler(const char *name,
39                   const struct hlist_head *handlers)
40 {
41         struct prop_handler *h;
42
43         if (!handlers) {
44                 u64 hash = btrfs_name_hash(name, strlen(name));
45
46                 handlers = find_prop_handlers_by_hash(hash);
47                 if (!handlers)
48                         return NULL;
49         }
50
51         hlist_for_each_entry(h, handlers, node)
52                 if (!strcmp(h->xattr_name, name))
53                         return h;
54
55         return NULL;
56 }
57
58 int btrfs_validate_prop(const char *name, const char *value, size_t value_len)
59 {
60         const struct prop_handler *handler;
61
62         if (strlen(name) <= XATTR_BTRFS_PREFIX_LEN)
63                 return -EINVAL;
64
65         handler = find_prop_handler(name, NULL);
66         if (!handler)
67                 return -EINVAL;
68
69         if (value_len == 0)
70                 return 0;
71
72         return handler->validate(value, value_len);
73 }
74
75 int btrfs_set_prop(struct btrfs_trans_handle *trans, struct inode *inode,
76                    const char *name, const char *value, size_t value_len,
77                    int flags)
78 {
79         const struct prop_handler *handler;
80         int ret;
81
82         handler = find_prop_handler(name, NULL);
83         if (!handler)
84                 return -EINVAL;
85
86         if (value_len == 0) {
87                 ret = btrfs_setxattr(trans, inode, handler->xattr_name,
88                                      NULL, 0, flags);
89                 if (ret)
90                         return ret;
91
92                 ret = handler->apply(inode, NULL, 0);
93                 ASSERT(ret == 0);
94
95                 return ret;
96         }
97
98         ret = btrfs_setxattr(trans, inode, handler->xattr_name, value,
99                              value_len, flags);
100         if (ret)
101                 return ret;
102         ret = handler->apply(inode, value, value_len);
103         if (ret) {
104                 btrfs_setxattr(trans, inode, handler->xattr_name, NULL,
105                                0, flags);
106                 return ret;
107         }
108
109         set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
110
111         return 0;
112 }
113
114 static int iterate_object_props(struct btrfs_root *root,
115                                 struct btrfs_path *path,
116                                 u64 objectid,
117                                 void (*iterator)(void *,
118                                                  const struct prop_handler *,
119                                                  const char *,
120                                                  size_t),
121                                 void *ctx)
122 {
123         int ret;
124         char *name_buf = NULL;
125         char *value_buf = NULL;
126         int name_buf_len = 0;
127         int value_buf_len = 0;
128
129         while (1) {
130                 struct btrfs_key key;
131                 struct btrfs_dir_item *di;
132                 struct extent_buffer *leaf;
133                 u32 total_len, cur, this_len;
134                 int slot;
135                 const struct hlist_head *handlers;
136
137                 slot = path->slots[0];
138                 leaf = path->nodes[0];
139
140                 if (slot >= btrfs_header_nritems(leaf)) {
141                         ret = btrfs_next_leaf(root, path);
142                         if (ret < 0)
143                                 goto out;
144                         else if (ret > 0)
145                                 break;
146                         continue;
147                 }
148
149                 btrfs_item_key_to_cpu(leaf, &key, slot);
150                 if (key.objectid != objectid)
151                         break;
152                 if (key.type != BTRFS_XATTR_ITEM_KEY)
153                         break;
154
155                 handlers = find_prop_handlers_by_hash(key.offset);
156                 if (!handlers)
157                         goto next_slot;
158
159                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
160                 cur = 0;
161                 total_len = btrfs_item_size_nr(leaf, slot);
162
163                 while (cur < total_len) {
164                         u32 name_len = btrfs_dir_name_len(leaf, di);
165                         u32 data_len = btrfs_dir_data_len(leaf, di);
166                         unsigned long name_ptr, data_ptr;
167                         const struct prop_handler *handler;
168
169                         this_len = sizeof(*di) + name_len + data_len;
170                         name_ptr = (unsigned long)(di + 1);
171                         data_ptr = name_ptr + name_len;
172
173                         if (name_len <= XATTR_BTRFS_PREFIX_LEN ||
174                             memcmp_extent_buffer(leaf, XATTR_BTRFS_PREFIX,
175                                                  name_ptr,
176                                                  XATTR_BTRFS_PREFIX_LEN))
177                                 goto next_dir_item;
178
179                         if (name_len >= name_buf_len) {
180                                 kfree(name_buf);
181                                 name_buf_len = name_len + 1;
182                                 name_buf = kmalloc(name_buf_len, GFP_NOFS);
183                                 if (!name_buf) {
184                                         ret = -ENOMEM;
185                                         goto out;
186                                 }
187                         }
188                         read_extent_buffer(leaf, name_buf, name_ptr, name_len);
189                         name_buf[name_len] = '\0';
190
191                         handler = find_prop_handler(name_buf, handlers);
192                         if (!handler)
193                                 goto next_dir_item;
194
195                         if (data_len > value_buf_len) {
196                                 kfree(value_buf);
197                                 value_buf_len = data_len;
198                                 value_buf = kmalloc(data_len, GFP_NOFS);
199                                 if (!value_buf) {
200                                         ret = -ENOMEM;
201                                         goto out;
202                                 }
203                         }
204                         read_extent_buffer(leaf, value_buf, data_ptr, data_len);
205
206                         iterator(ctx, handler, value_buf, data_len);
207 next_dir_item:
208                         cur += this_len;
209                         di = (struct btrfs_dir_item *)((char *) di + this_len);
210                 }
211
212 next_slot:
213                 path->slots[0]++;
214         }
215
216         ret = 0;
217 out:
218         btrfs_release_path(path);
219         kfree(name_buf);
220         kfree(value_buf);
221
222         return ret;
223 }
224
225 static void inode_prop_iterator(void *ctx,
226                                 const struct prop_handler *handler,
227                                 const char *value,
228                                 size_t len)
229 {
230         struct inode *inode = ctx;
231         struct btrfs_root *root = BTRFS_I(inode)->root;
232         int ret;
233
234         ret = handler->apply(inode, value, len);
235         if (unlikely(ret))
236                 btrfs_warn(root->fs_info,
237                            "error applying prop %s to ino %llu (root %llu): %d",
238                            handler->xattr_name, btrfs_ino(BTRFS_I(inode)),
239                            root->root_key.objectid, ret);
240         else
241                 set_bit(BTRFS_INODE_HAS_PROPS, &BTRFS_I(inode)->runtime_flags);
242 }
243
244 int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path)
245 {
246         struct btrfs_root *root = BTRFS_I(inode)->root;
247         u64 ino = btrfs_ino(BTRFS_I(inode));
248         int ret;
249
250         ret = iterate_object_props(root, path, ino, inode_prop_iterator, inode);
251
252         return ret;
253 }
254
255 static int prop_compression_validate(const char *value, size_t len)
256 {
257         if (!value)
258                 return 0;
259
260         if (btrfs_compress_is_valid_type(value, len))
261                 return 0;
262
263         return -EINVAL;
264 }
265
266 static int prop_compression_apply(struct inode *inode, const char *value,
267                                   size_t len)
268 {
269         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
270         int type;
271
272         if (len == 0) {
273                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
274                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
275                 BTRFS_I(inode)->prop_compress = BTRFS_COMPRESS_NONE;
276
277                 return 0;
278         }
279
280         if (!strncmp("lzo", value, 3)) {
281                 type = BTRFS_COMPRESS_LZO;
282                 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
283         } else if (!strncmp("zlib", value, 4)) {
284                 type = BTRFS_COMPRESS_ZLIB;
285         } else if (!strncmp("zstd", value, 4)) {
286                 type = BTRFS_COMPRESS_ZSTD;
287                 btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
288         } else {
289                 return -EINVAL;
290         }
291
292         BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
293         BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
294         BTRFS_I(inode)->prop_compress = type;
295
296         return 0;
297 }
298
299 static const char *prop_compression_extract(struct inode *inode)
300 {
301         switch (BTRFS_I(inode)->prop_compress) {
302         case BTRFS_COMPRESS_ZLIB:
303         case BTRFS_COMPRESS_LZO:
304         case BTRFS_COMPRESS_ZSTD:
305                 return btrfs_compress_type2str(BTRFS_I(inode)->prop_compress);
306         default:
307                 break;
308         }
309
310         return NULL;
311 }
312
313 static struct prop_handler prop_handlers[] = {
314         {
315                 .xattr_name = XATTR_BTRFS_PREFIX "compression",
316                 .validate = prop_compression_validate,
317                 .apply = prop_compression_apply,
318                 .extract = prop_compression_extract,
319                 .inheritable = 1
320         },
321 };
322
323 static int inherit_props(struct btrfs_trans_handle *trans,
324                          struct inode *inode,
325                          struct inode *parent)
326 {
327         struct btrfs_root *root = BTRFS_I(inode)->root;
328         struct btrfs_fs_info *fs_info = root->fs_info;
329         int ret;
330         int i;
331         bool need_reserve = false;
332
333         if (!test_bit(BTRFS_INODE_HAS_PROPS,
334                       &BTRFS_I(parent)->runtime_flags))
335                 return 0;
336
337         for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
338                 const struct prop_handler *h = &prop_handlers[i];
339                 const char *value;
340                 u64 num_bytes = 0;
341
342                 if (!h->inheritable)
343                         continue;
344
345                 value = h->extract(parent);
346                 if (!value)
347                         continue;
348
349                 /*
350                  * This is not strictly necessary as the property should be
351                  * valid, but in case it isn't, don't propagate it futher.
352                  */
353                 ret = h->validate(value, strlen(value));
354                 if (ret)
355                         continue;
356
357                 /*
358                  * Currently callers should be reserving 1 item for properties,
359                  * since we only have 1 property that we currently support.  If
360                  * we add more in the future we need to try and reserve more
361                  * space for them.  But we should also revisit how we do space
362                  * reservations if we do add more properties in the future.
363                  */
364                 if (need_reserve) {
365                         num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
366                         ret = btrfs_block_rsv_add(root, trans->block_rsv,
367                                         num_bytes, BTRFS_RESERVE_NO_FLUSH);
368                         if (ret)
369                                 return ret;
370                 }
371
372                 ret = btrfs_setxattr(trans, inode, h->xattr_name, value,
373                                      strlen(value), 0);
374                 if (!ret) {
375                         ret = h->apply(inode, value, strlen(value));
376                         if (ret)
377                                 btrfs_setxattr(trans, inode, h->xattr_name,
378                                                NULL, 0, 0);
379                         else
380                                 set_bit(BTRFS_INODE_HAS_PROPS,
381                                         &BTRFS_I(inode)->runtime_flags);
382                 }
383
384                 if (need_reserve) {
385                         btrfs_block_rsv_release(fs_info, trans->block_rsv,
386                                         num_bytes, NULL);
387                         if (ret)
388                                 return ret;
389                 }
390                 need_reserve = true;
391         }
392
393         return 0;
394 }
395
396 int btrfs_inode_inherit_props(struct btrfs_trans_handle *trans,
397                               struct inode *inode,
398                               struct inode *dir)
399 {
400         if (!dir)
401                 return 0;
402
403         return inherit_props(trans, inode, dir);
404 }
405
406 int btrfs_subvol_inherit_props(struct btrfs_trans_handle *trans,
407                                struct btrfs_root *root,
408                                struct btrfs_root *parent_root)
409 {
410         struct super_block *sb = root->fs_info->sb;
411         struct inode *parent_inode, *child_inode;
412         int ret;
413
414         parent_inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, parent_root);
415         if (IS_ERR(parent_inode))
416                 return PTR_ERR(parent_inode);
417
418         child_inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, root);
419         if (IS_ERR(child_inode)) {
420                 iput(parent_inode);
421                 return PTR_ERR(child_inode);
422         }
423
424         ret = inherit_props(trans, child_inode, parent_inode);
425         iput(child_inode);
426         iput(parent_inode);
427
428         return ret;
429 }
430
431 void __init btrfs_props_init(void)
432 {
433         int i;
434
435         for (i = 0; i < ARRAY_SIZE(prop_handlers); i++) {
436                 struct prop_handler *p = &prop_handlers[i];
437                 u64 h = btrfs_name_hash(p->xattr_name, strlen(p->xattr_name));
438
439                 hash_add(prop_handlers_ht, &p->node, h);
440         }
441 }
442