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1 | /* |
1 | /* |
2 | * Copyright (c) 2008 Jakub Jermar |
2 | * Copyright (c) 2008 Jakub Jermar |
3 | * All rights reserved. |
3 | * All rights reserved. |
4 | * |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
7 | * are met: |
8 | * |
8 | * |
9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
13 | * documentation and/or other materials provided with the distribution. |
14 | * - The name of the author may not be used to endorse or promote products |
14 | * - The name of the author may not be used to endorse or promote products |
15 | * derived from this software without specific prior written permission. |
15 | * derived from this software without specific prior written permission. |
16 | * |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
27 | */ |
28 | 28 | ||
29 | /** @addtogroup fs |
29 | /** @addtogroup fs |
30 | * @{ |
30 | * @{ |
31 | */ |
31 | */ |
32 | 32 | ||
33 | /** |
33 | /** |
34 | * @file fat_idx.c |
34 | * @file fat_idx.c |
35 | * @brief Layer for translating FAT entities to VFS node indices. |
35 | * @brief Layer for translating FAT entities to VFS node indices. |
36 | */ |
36 | */ |
37 | 37 | ||
38 | #include "fat.h" |
38 | #include "fat.h" |
39 | #include "../../vfs/vfs.h" |
39 | #include "../../vfs/vfs.h" |
40 | #include <errno.h> |
40 | #include <errno.h> |
41 | #include <string.h> |
41 | #include <string.h> |
42 | #include <libadt/hash_table.h> |
42 | #include <libadt/hash_table.h> |
43 | #include <libadt/list.h> |
43 | #include <libadt/list.h> |
44 | #include <assert.h> |
44 | #include <assert.h> |
45 | #include <futex.h> |
45 | #include <futex.h> |
46 | 46 | ||
47 | /** Each instance of this type describes one interval of freed VFS indices. */ |
47 | /** Each instance of this type describes one interval of freed VFS indices. */ |
48 | typedef struct { |
48 | typedef struct { |
49 | link_t link; |
49 | link_t link; |
50 | fs_index_t first; |
50 | fs_index_t first; |
51 | fs_index_t last; |
51 | fs_index_t last; |
52 | } freed_t; |
52 | } freed_t; |
53 | 53 | ||
54 | /** |
54 | /** |
55 | * Each instance of this type describes state of all VFS indices that |
55 | * Each instance of this type describes state of all VFS indices that |
56 | * are currently unused. |
56 | * are currently unused. |
57 | */ |
57 | */ |
58 | typedef struct { |
58 | typedef struct { |
59 | link_t link; |
59 | link_t link; |
60 | dev_handle_t dev_handle; |
60 | dev_handle_t dev_handle; |
61 | 61 | ||
62 | /** Next unassigned index. */ |
62 | /** Next unassigned index. */ |
63 | fs_index_t next; |
63 | fs_index_t next; |
64 | /** Number of remaining unassigned indices. */ |
64 | /** Number of remaining unassigned indices. */ |
65 | uint64_t remaining; |
65 | uint64_t remaining; |
66 | 66 | ||
67 | /** Sorted list of intervals of freed indices. */ |
67 | /** Sorted list of intervals of freed indices. */ |
68 | link_t freed_head; |
68 | link_t freed_head; |
69 | } unused_t; |
69 | } unused_t; |
70 | 70 | ||
71 | /** Futex protecting the list of unused structures. */ |
71 | /** Futex protecting the list of unused structures. */ |
72 | static futex_t unused_futex = FUTEX_INITIALIZER; |
72 | static futex_t unused_futex = FUTEX_INITIALIZER; |
73 | 73 | ||
74 | /** List of unused structures. */ |
74 | /** List of unused structures. */ |
75 | static LIST_INITIALIZE(unused_head); |
75 | static LIST_INITIALIZE(unused_head); |
76 | 76 | ||
- | 77 | /** Futex protecting the up_hash and ui_hash. |
|
- | 78 | * |
|
- | 79 | * The locking strategy assumes that there will be at most one fibril for each |
|
- | 80 | * dev_handle. Therefore it will be sufficient to hold the futex for shorter |
|
- | 81 | * times (i.e. only during hash table operations as opposed to holding it the |
|
- | 82 | * whole time between an unsuccessful find and the following insert). Should the |
|
- | 83 | * assumption break, the locking strategy for this futex will have to be |
|
- | 84 | * reconsidered. |
|
- | 85 | */ |
|
- | 86 | static futex_t used_futex = FUTEX_INITIALIZER; |
|
- | 87 | ||
77 | /** |
88 | /** |
78 | * Global hash table of all used fat_idx_t structures. |
89 | * Global hash table of all used fat_idx_t structures. |
79 | * The index structures are hashed by the dev_handle, parent node's first |
90 | * The index structures are hashed by the dev_handle, parent node's first |
80 | * cluster and index within the parent directory. |
91 | * cluster and index within the parent directory. |
81 | */ |
92 | */ |
82 | static hash_table_t up_hash; |
93 | static hash_table_t up_hash; |
83 | 94 | ||
84 | #define UPH_BUCKETS_LOG 12 |
95 | #define UPH_BUCKETS_LOG 12 |
85 | #define UPH_BUCKETS (1 << UPH_BUCKETS_LOG) |
96 | #define UPH_BUCKETS (1 << UPH_BUCKETS_LOG) |
86 | 97 | ||
87 | #define UPH_DH_KEY 0 |
98 | #define UPH_DH_KEY 0 |
88 | #define UPH_PFC_KEY 1 |
99 | #define UPH_PFC_KEY 1 |
89 | #define UPH_PDI_KEY 2 |
100 | #define UPH_PDI_KEY 2 |
90 | 101 | ||
91 | static hash_index_t pos_hash(unsigned long key[]) |
102 | static hash_index_t pos_hash(unsigned long key[]) |
92 | { |
103 | { |
93 | dev_handle_t dev_handle = (dev_handle_t)key[UPH_DH_KEY]; |
104 | dev_handle_t dev_handle = (dev_handle_t)key[UPH_DH_KEY]; |
94 | fat_cluster_t pfc = (fat_cluster_t)key[UPH_PFC_KEY]; |
105 | fat_cluster_t pfc = (fat_cluster_t)key[UPH_PFC_KEY]; |
95 | unsigned pdi = (unsigned)key[UPH_PDI_KEY]; |
106 | unsigned pdi = (unsigned)key[UPH_PDI_KEY]; |
96 | 107 | ||
97 | hash_index_t h; |
108 | hash_index_t h; |
98 | 109 | ||
99 | /* |
110 | /* |
100 | * The least significant half of all bits are the least significant bits |
111 | * The least significant half of all bits are the least significant bits |
101 | * of the parent node's first cluster. |
112 | * of the parent node's first cluster. |
102 | * |
113 | * |
103 | * The least significant half of the most significant half of all bits |
114 | * The least significant half of the most significant half of all bits |
104 | * are the least significant bits of the node's dentry index within the |
115 | * are the least significant bits of the node's dentry index within the |
105 | * parent directory node. |
116 | * parent directory node. |
106 | * |
117 | * |
107 | * The most significant half of the most significant half of all bits |
118 | * The most significant half of the most significant half of all bits |
108 | * are the least significant bits of the device handle. |
119 | * are the least significant bits of the device handle. |
109 | */ |
120 | */ |
110 | h = pfc & ((1 << (UPH_BUCKETS_LOG / 2)) - 1); |
121 | h = pfc & ((1 << (UPH_BUCKETS_LOG / 2)) - 1); |
111 | h |= (pdi & ((1 << (UPH_BUCKETS_LOG / 4)) - 1)) << |
122 | h |= (pdi & ((1 << (UPH_BUCKETS_LOG / 4)) - 1)) << |
112 | (UPH_BUCKETS_LOG / 2); |
123 | (UPH_BUCKETS_LOG / 2); |
113 | h |= (dev_handle & ((1 << (UPH_BUCKETS_LOG / 4)) - 1)) << |
124 | h |= (dev_handle & ((1 << (UPH_BUCKETS_LOG / 4)) - 1)) << |
114 | (3 * (UPH_BUCKETS_LOG / 4)); |
125 | (3 * (UPH_BUCKETS_LOG / 4)); |
115 | 126 | ||
116 | return h; |
127 | return h; |
117 | } |
128 | } |
118 | 129 | ||
119 | static int pos_compare(unsigned long key[], hash_count_t keys, link_t *item) |
130 | static int pos_compare(unsigned long key[], hash_count_t keys, link_t *item) |
120 | { |
131 | { |
121 | dev_handle_t dev_handle = (dev_handle_t)key[UPH_DH_KEY]; |
132 | dev_handle_t dev_handle = (dev_handle_t)key[UPH_DH_KEY]; |
122 | fat_cluster_t pfc = (fat_cluster_t)key[UPH_PFC_KEY]; |
133 | fat_cluster_t pfc = (fat_cluster_t)key[UPH_PFC_KEY]; |
123 | unsigned pdi = (unsigned)key[UPH_PDI_KEY]; |
134 | unsigned pdi = (unsigned)key[UPH_PDI_KEY]; |
124 | fat_idx_t *fidx = list_get_instance(item, fat_idx_t, uph_link); |
135 | fat_idx_t *fidx = list_get_instance(item, fat_idx_t, uph_link); |
125 | 136 | ||
126 | return (dev_handle == fidx->dev_handle) && (pfc == fidx->pfc) && |
137 | return (dev_handle == fidx->dev_handle) && (pfc == fidx->pfc) && |
127 | (pdi == fidx->pdi); |
138 | (pdi == fidx->pdi); |
128 | } |
139 | } |
129 | 140 | ||
130 | static void pos_remove_callback(link_t *item) |
141 | static void pos_remove_callback(link_t *item) |
131 | { |
142 | { |
132 | /* nothing to do */ |
143 | /* nothing to do */ |
133 | } |
144 | } |
134 | 145 | ||
135 | static hash_table_operations_t uph_ops = { |
146 | static hash_table_operations_t uph_ops = { |
136 | .hash = pos_hash, |
147 | .hash = pos_hash, |
137 | .compare = pos_compare, |
148 | .compare = pos_compare, |
138 | .remove_callback = pos_remove_callback, |
149 | .remove_callback = pos_remove_callback, |
139 | }; |
150 | }; |
140 | 151 | ||
141 | /** |
152 | /** |
142 | * Global hash table of all used fat_idx_t structures. |
153 | * Global hash table of all used fat_idx_t structures. |
143 | * The index structures are hashed by the dev_handle and index. |
154 | * The index structures are hashed by the dev_handle and index. |
144 | */ |
155 | */ |
145 | static hash_table_t ui_hash; |
156 | static hash_table_t ui_hash; |
146 | 157 | ||
147 | #define UIH_BUCKETS_LOG 12 |
158 | #define UIH_BUCKETS_LOG 12 |
148 | #define UIH_BUCKETS (1 << UIH_BUCKETS_LOG) |
159 | #define UIH_BUCKETS (1 << UIH_BUCKETS_LOG) |
149 | 160 | ||
150 | #define UIH_DH_KEY 0 |
161 | #define UIH_DH_KEY 0 |
151 | #define UIH_INDEX_KEY 1 |
162 | #define UIH_INDEX_KEY 1 |
152 | 163 | ||
153 | static hash_index_t idx_hash(unsigned long key[]) |
164 | static hash_index_t idx_hash(unsigned long key[]) |
154 | { |
165 | { |
155 | dev_handle_t dev_handle = (dev_handle_t)key[UIH_DH_KEY]; |
166 | dev_handle_t dev_handle = (dev_handle_t)key[UIH_DH_KEY]; |
156 | fs_index_t index = (fs_index_t)key[UIH_INDEX_KEY]; |
167 | fs_index_t index = (fs_index_t)key[UIH_INDEX_KEY]; |
157 | 168 | ||
158 | hash_index_t h; |
169 | hash_index_t h; |
159 | 170 | ||
160 | h = dev_handle & ((1 << (UIH_BUCKETS_LOG / 2)) - 1); |
171 | h = dev_handle & ((1 << (UIH_BUCKETS_LOG / 2)) - 1); |
161 | h |= (index & ((1 << (UIH_BUCKETS_LOG / 2)) - 1)) << |
172 | h |= (index & ((1 << (UIH_BUCKETS_LOG / 2)) - 1)) << |
162 | (UIH_BUCKETS_LOG / 2); |
173 | (UIH_BUCKETS_LOG / 2); |
163 | 174 | ||
164 | return h; |
175 | return h; |
165 | } |
176 | } |
166 | 177 | ||
167 | static int idx_compare(unsigned long key[], hash_count_t keys, link_t *item) |
178 | static int idx_compare(unsigned long key[], hash_count_t keys, link_t *item) |
168 | { |
179 | { |
169 | dev_handle_t dev_handle = (dev_handle_t)key[UIH_DH_KEY]; |
180 | dev_handle_t dev_handle = (dev_handle_t)key[UIH_DH_KEY]; |
170 | fs_index_t index = (fs_index_t)key[UIH_INDEX_KEY]; |
181 | fs_index_t index = (fs_index_t)key[UIH_INDEX_KEY]; |
171 | fat_idx_t *fidx = list_get_instance(item, fat_idx_t, uih_link); |
182 | fat_idx_t *fidx = list_get_instance(item, fat_idx_t, uih_link); |
172 | 183 | ||
173 | return (dev_handle == fidx->dev_handle) && (index == fidx->index); |
184 | return (dev_handle == fidx->dev_handle) && (index == fidx->index); |
174 | } |
185 | } |
175 | 186 | ||
176 | static void idx_remove_callback(link_t *item) |
187 | static void idx_remove_callback(link_t *item) |
177 | { |
188 | { |
178 | /* nothing to do */ |
189 | /* nothing to do */ |
179 | } |
190 | } |
180 | 191 | ||
181 | static hash_table_operations_t uih_ops = { |
192 | static hash_table_operations_t uih_ops = { |
182 | .hash = idx_hash, |
193 | .hash = idx_hash, |
183 | .compare = idx_compare, |
194 | .compare = idx_compare, |
184 | .remove_callback = idx_remove_callback, |
195 | .remove_callback = idx_remove_callback, |
185 | }; |
196 | }; |
186 | 197 | ||
187 | /** Allocate a VFS index which is not currently in use. */ |
198 | /** Allocate a VFS index which is not currently in use. */ |
188 | static bool fat_idx_alloc(dev_handle_t dev_handle, fs_index_t *index) |
199 | static bool fat_idx_alloc(dev_handle_t dev_handle, fs_index_t *index) |
189 | { |
200 | { |
190 | link_t *l; |
201 | link_t *l; |
191 | unused_t *u; |
202 | unused_t *u; |
192 | 203 | ||
193 | assert(index); |
204 | assert(index); |
194 | futex_down(&unused_futex); |
205 | futex_down(&unused_futex); |
195 | for (l = unused_head.next; l != &unused_head; l = l->next) { |
206 | for (l = unused_head.next; l != &unused_head; l = l->next) { |
196 | u = list_get_instance(l, unused_t, link); |
207 | u = list_get_instance(l, unused_t, link); |
197 | if (u->dev_handle == dev_handle) |
208 | if (u->dev_handle == dev_handle) |
198 | goto hit; |
209 | goto hit; |
199 | } |
210 | } |
200 | futex_up(&unused_futex); |
211 | futex_up(&unused_futex); |
201 | 212 | ||
202 | /* dev_handle not found */ |
213 | /* dev_handle not found */ |
203 | return false; |
214 | return false; |
204 | 215 | ||
205 | hit: |
216 | hit: |
206 | if (list_empty(&u->freed_head)) { |
217 | if (list_empty(&u->freed_head)) { |
207 | if (u->remaining) { |
218 | if (u->remaining) { |
208 | /* |
219 | /* |
209 | * There are no freed indices, allocate one directly |
220 | * There are no freed indices, allocate one directly |
210 | * from the counter. |
221 | * from the counter. |
211 | */ |
222 | */ |
212 | *index = u->next++; |
223 | *index = u->next++; |
213 | --u->remaining; |
224 | --u->remaining; |
214 | futex_up(&unused_futex); |
225 | futex_up(&unused_futex); |
215 | return true; |
226 | return true; |
216 | } |
227 | } |
217 | } else { |
228 | } else { |
218 | /* There are some freed indices which we can reuse. */ |
229 | /* There are some freed indices which we can reuse. */ |
219 | freed_t *f = list_get_instance(u->freed_head.next, freed_t, |
230 | freed_t *f = list_get_instance(u->freed_head.next, freed_t, |
220 | link); |
231 | link); |
221 | *index = f->first; |
232 | *index = f->first; |
222 | if (f->first++ == f->last) { |
233 | if (f->first++ == f->last) { |
223 | /* Destroy the interval. */ |
234 | /* Destroy the interval. */ |
224 | list_remove(&f->link); |
235 | list_remove(&f->link); |
225 | free(f); |
236 | free(f); |
226 | } |
237 | } |
227 | futex_up(&unused_futex); |
238 | futex_up(&unused_futex); |
228 | return true; |
239 | return true; |
229 | } |
240 | } |
230 | /* |
241 | /* |
231 | * We ran out of indices, which is extremely unlikely with FAT16, but |
242 | * We ran out of indices, which is extremely unlikely with FAT16, but |
232 | * theoretically still possible (e.g. too many open unlinked nodes or |
243 | * theoretically still possible (e.g. too many open unlinked nodes or |
233 | * too many zero-sized nodes). |
244 | * too many zero-sized nodes). |
234 | */ |
245 | */ |
235 | futex_up(&unused_futex); |
246 | futex_up(&unused_futex); |
236 | return false; |
247 | return false; |
237 | } |
248 | } |
238 | 249 | ||
239 | /** If possible, coalesce two intervals of freed indices. */ |
250 | /** If possible, coalesce two intervals of freed indices. */ |
240 | static void try_coalesce_intervals(link_t *l, link_t *r, link_t *cur) |
251 | static void try_coalesce_intervals(link_t *l, link_t *r, link_t *cur) |
241 | { |
252 | { |
242 | freed_t *fl = list_get_instance(l, freed_t, link); |
253 | freed_t *fl = list_get_instance(l, freed_t, link); |
243 | freed_t *fr = list_get_instance(r, freed_t, link); |
254 | freed_t *fr = list_get_instance(r, freed_t, link); |
244 | 255 | ||
245 | if (fl->last + 1 == fr->first) { |
256 | if (fl->last + 1 == fr->first) { |
246 | if (cur == l) { |
257 | if (cur == l) { |
247 | fl->last = fr->last; |
258 | fl->last = fr->last; |
248 | list_remove(r); |
259 | list_remove(r); |
249 | free(r); |
260 | free(r); |
250 | } else { |
261 | } else { |
251 | fr->first = fl->first; |
262 | fr->first = fl->first; |
252 | list_remove(l); |
263 | list_remove(l); |
253 | free(l); |
264 | free(l); |
254 | } |
265 | } |
255 | } |
266 | } |
256 | } |
267 | } |
257 | 268 | ||
258 | /** Free a VFS index, which is no longer in use. */ |
269 | /** Free a VFS index, which is no longer in use. */ |
259 | static void fat_idx_free(dev_handle_t dev_handle, fs_index_t index) |
270 | static void fat_idx_free(dev_handle_t dev_handle, fs_index_t index) |
260 | { |
271 | { |
261 | link_t *l; |
272 | link_t *l; |
262 | unused_t *u; |
273 | unused_t *u; |
263 | 274 | ||
264 | futex_down(&unused_futex); |
275 | futex_down(&unused_futex); |
265 | for (l = unused_head.next; l != &unused_head; l = l->next) { |
276 | for (l = unused_head.next; l != &unused_head; l = l->next) { |
266 | u = list_get_instance(l, unused_t, link); |
277 | u = list_get_instance(l, unused_t, link); |
267 | if (u->dev_handle == dev_handle) |
278 | if (u->dev_handle == dev_handle) |
268 | goto hit; |
279 | goto hit; |
269 | } |
280 | } |
270 | futex_up(&unused_futex); |
281 | futex_up(&unused_futex); |
271 | 282 | ||
272 | /* should not happen */ |
283 | /* should not happen */ |
273 | assert(0); |
284 | assert(0); |
274 | 285 | ||
275 | hit: |
286 | hit: |
276 | if (u->next == index + 1) { |
287 | if (u->next == index + 1) { |
277 | /* The index can be returned directly to the counter. */ |
288 | /* The index can be returned directly to the counter. */ |
278 | u->next--; |
289 | u->next--; |
279 | u->remaining++; |
290 | u->remaining++; |
280 | } else { |
291 | } else { |
281 | /* |
292 | /* |
282 | * The index must be returned either to an existing freed |
293 | * The index must be returned either to an existing freed |
283 | * interval or a new interval must be created. |
294 | * interval or a new interval must be created. |
284 | */ |
295 | */ |
285 | link_t *lnk; |
296 | link_t *lnk; |
286 | freed_t *n; |
297 | freed_t *n; |
287 | for (lnk = u->freed_head.next; lnk != &u->freed_head; |
298 | for (lnk = u->freed_head.next; lnk != &u->freed_head; |
288 | lnk = lnk->next) { |
299 | lnk = lnk->next) { |
289 | freed_t *f = list_get_instance(lnk, freed_t, link); |
300 | freed_t *f = list_get_instance(lnk, freed_t, link); |
290 | if (f->first == index + 1) { |
301 | if (f->first == index + 1) { |
291 | f->first--; |
302 | f->first--; |
292 | if (lnk->prev != &u->freed_head) |
303 | if (lnk->prev != &u->freed_head) |
293 | try_coalesce_intervals(lnk->prev, lnk, |
304 | try_coalesce_intervals(lnk->prev, lnk, |
294 | lnk); |
305 | lnk); |
295 | futex_up(&unused_futex); |
306 | futex_up(&unused_futex); |
296 | return; |
307 | return; |
297 | } |
308 | } |
298 | if (f->last == index - 1) { |
309 | if (f->last == index - 1) { |
299 | f->last++; |
310 | f->last++; |
300 | if (lnk->next != &u->freed_head) |
311 | if (lnk->next != &u->freed_head) |
301 | try_coalesce_intervals(lnk, lnk->next, |
312 | try_coalesce_intervals(lnk, lnk->next, |
302 | lnk); |
313 | lnk); |
303 | futex_up(&unused_futex); |
314 | futex_up(&unused_futex); |
304 | return; |
315 | return; |
305 | } |
316 | } |
306 | if (index > f->first) { |
317 | if (index > f->first) { |
307 | n = malloc(sizeof(freed_t)); |
318 | n = malloc(sizeof(freed_t)); |
308 | /* TODO: sleep until allocation succeeds */ |
319 | /* TODO: sleep until allocation succeeds */ |
309 | assert(n); |
320 | assert(n); |
310 | link_initialize(&n->link); |
321 | link_initialize(&n->link); |
311 | n->first = index; |
322 | n->first = index; |
312 | n->last = index; |
323 | n->last = index; |
313 | list_insert_before(&n->link, lnk); |
324 | list_insert_before(&n->link, lnk); |
314 | futex_up(&unused_futex); |
325 | futex_up(&unused_futex); |
315 | return; |
326 | return; |
316 | } |
327 | } |
317 | 328 | ||
318 | } |
329 | } |
319 | /* The index will form the last interval. */ |
330 | /* The index will form the last interval. */ |
320 | n = malloc(sizeof(freed_t)); |
331 | n = malloc(sizeof(freed_t)); |
321 | /* TODO: sleep until allocation succeeds */ |
332 | /* TODO: sleep until allocation succeeds */ |
322 | assert(n); |
333 | assert(n); |
323 | link_initialize(&n->link); |
334 | link_initialize(&n->link); |
324 | n->first = index; |
335 | n->first = index; |
325 | n->last = index; |
336 | n->last = index; |
326 | list_append(&n->link, &u->freed_head); |
337 | list_append(&n->link, &u->freed_head); |
327 | } |
338 | } |
328 | futex_up(&unused_futex); |
339 | futex_up(&unused_futex); |
329 | } |
340 | } |
330 | 341 | ||
331 | fat_idx_t * |
342 | fat_idx_t * |
332 | fat_idx_get_by_pos(dev_handle_t dev_handle, fat_cluster_t pfc, unsigned pdi) |
343 | fat_idx_get_by_pos(dev_handle_t dev_handle, fat_cluster_t pfc, unsigned pdi) |
333 | { |
344 | { |
334 | fat_idx_t *fidx; |
345 | fat_idx_t *fidx; |
335 | link_t *l; |
346 | link_t *l; |
336 | unsigned long pkey[] = { |
347 | unsigned long pkey[] = { |
337 | [UPH_DH_KEY] = dev_handle, |
348 | [UPH_DH_KEY] = dev_handle, |
338 | [UPH_PFC_KEY] = pfc, |
349 | [UPH_PFC_KEY] = pfc, |
339 | [UPH_PDI_KEY] = pdi, |
350 | [UPH_PDI_KEY] = pdi, |
340 | }; |
351 | }; |
341 | 352 | ||
- | 353 | futex_down(&used_futex); |
|
342 | l = hash_table_find(&up_hash, pkey); |
354 | l = hash_table_find(&up_hash, pkey); |
- | 355 | futex_up(&used_futex); |
|
343 | if (l) { |
356 | if (l) { |
344 | fidx = hash_table_get_instance(l, fat_idx_t, uph_link); |
357 | fidx = hash_table_get_instance(l, fat_idx_t, uph_link); |
345 | } else { |
358 | } else { |
346 | fidx = (fat_idx_t *) malloc(sizeof(fat_idx_t)); |
359 | fidx = (fat_idx_t *) malloc(sizeof(fat_idx_t)); |
347 | if (!fidx) { |
360 | if (!fidx) { |
348 | return NULL; |
361 | return NULL; |
349 | } |
362 | } |
350 | if (!fat_idx_alloc(dev_handle, &fidx->index)) { |
363 | if (!fat_idx_alloc(dev_handle, &fidx->index)) { |
351 | free(fidx); |
364 | free(fidx); |
352 | return NULL; |
365 | return NULL; |
353 | } |
366 | } |
354 | 367 | ||
355 | unsigned long ikey[] = { |
368 | unsigned long ikey[] = { |
356 | [UIH_DH_KEY] = dev_handle, |
369 | [UIH_DH_KEY] = dev_handle, |
357 | [UIH_INDEX_KEY] = fidx->index, |
370 | [UIH_INDEX_KEY] = fidx->index, |
358 | }; |
371 | }; |
359 | 372 | ||
360 | link_initialize(&fidx->uph_link); |
373 | link_initialize(&fidx->uph_link); |
361 | link_initialize(&fidx->uih_link); |
374 | link_initialize(&fidx->uih_link); |
362 | fidx->dev_handle = dev_handle; |
375 | fidx->dev_handle = dev_handle; |
363 | fidx->pfc = pfc; |
376 | fidx->pfc = pfc; |
364 | fidx->pdi = pdi; |
377 | fidx->pdi = pdi; |
365 | fidx->nodep = NULL; |
378 | fidx->nodep = NULL; |
366 | 379 | ||
- | 380 | futex_down(&used_futex); |
|
367 | hash_table_insert(&up_hash, pkey, &fidx->uph_link); |
381 | hash_table_insert(&up_hash, pkey, &fidx->uph_link); |
368 | hash_table_insert(&ui_hash, ikey, &fidx->uih_link); |
382 | hash_table_insert(&ui_hash, ikey, &fidx->uih_link); |
- | 383 | futex_up(&used_futex); |
|
369 | } |
384 | } |
370 | 385 | ||
371 | return fidx; |
386 | return fidx; |
372 | } |
387 | } |
373 | 388 | ||
374 | fat_idx_t * |
389 | fat_idx_t * |
375 | fat_idx_get_by_index(dev_handle_t dev_handle, fs_index_t index) |
390 | fat_idx_get_by_index(dev_handle_t dev_handle, fs_index_t index) |
376 | { |
391 | { |
377 | fat_idx_t *fidx = NULL; |
392 | fat_idx_t *fidx = NULL; |
378 | link_t *l; |
393 | link_t *l; |
379 | unsigned long ikey[] = { |
394 | unsigned long ikey[] = { |
380 | [UIH_DH_KEY] = dev_handle, |
395 | [UIH_DH_KEY] = dev_handle, |
381 | [UIH_INDEX_KEY] = index, |
396 | [UIH_INDEX_KEY] = index, |
382 | }; |
397 | }; |
383 | 398 | ||
- | 399 | futex_down(&used_futex); |
|
384 | l = hash_table_find(&ui_hash, ikey); |
400 | l = hash_table_find(&ui_hash, ikey); |
- | 401 | futex_up(&used_futex); |
|
385 | if (l) { |
402 | if (l) { |
386 | fidx = hash_table_get_instance(l, fat_idx_t, uih_link); |
403 | fidx = hash_table_get_instance(l, fat_idx_t, uih_link); |
387 | } |
404 | } |
388 | 405 | ||
389 | return fidx; |
406 | return fidx; |
390 | } |
407 | } |
391 | 408 | ||
392 | 409 |