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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. |
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; |
78 | static futex_t used_futex = FUTEX_INITIALIZER; |
87 | 79 | ||
88 | /** |
80 | /** |
89 | * Global hash table of all used fat_idx_t structures. |
81 | * Global hash table of all used fat_idx_t structures. |
90 | * The index structures are hashed by the dev_handle, parent node's first |
82 | * The index structures are hashed by the dev_handle, parent node's first |
91 | * cluster and index within the parent directory. |
83 | * cluster and index within the parent directory. |
92 | */ |
84 | */ |
93 | static hash_table_t up_hash; |
85 | static hash_table_t up_hash; |
94 | 86 | ||
95 | #define UPH_BUCKETS_LOG 12 |
87 | #define UPH_BUCKETS_LOG 12 |
96 | #define UPH_BUCKETS (1 << UPH_BUCKETS_LOG) |
88 | #define UPH_BUCKETS (1 << UPH_BUCKETS_LOG) |
97 | 89 | ||
98 | #define UPH_DH_KEY 0 |
90 | #define UPH_DH_KEY 0 |
99 | #define UPH_PFC_KEY 1 |
91 | #define UPH_PFC_KEY 1 |
100 | #define UPH_PDI_KEY 2 |
92 | #define UPH_PDI_KEY 2 |
101 | 93 | ||
102 | static hash_index_t pos_hash(unsigned long key[]) |
94 | static hash_index_t pos_hash(unsigned long key[]) |
103 | { |
95 | { |
104 | dev_handle_t dev_handle = (dev_handle_t)key[UPH_DH_KEY]; |
96 | dev_handle_t dev_handle = (dev_handle_t)key[UPH_DH_KEY]; |
105 | fat_cluster_t pfc = (fat_cluster_t)key[UPH_PFC_KEY]; |
97 | fat_cluster_t pfc = (fat_cluster_t)key[UPH_PFC_KEY]; |
106 | unsigned pdi = (unsigned)key[UPH_PDI_KEY]; |
98 | unsigned pdi = (unsigned)key[UPH_PDI_KEY]; |
107 | 99 | ||
108 | hash_index_t h; |
100 | hash_index_t h; |
109 | 101 | ||
110 | /* |
102 | /* |
111 | * The least significant half of all bits are the least significant bits |
103 | * The least significant half of all bits are the least significant bits |
112 | * of the parent node's first cluster. |
104 | * of the parent node's first cluster. |
113 | * |
105 | * |
114 | * The least significant half of the most significant half of all bits |
106 | * The least significant half of the most significant half of all bits |
115 | * are the least significant bits of the node's dentry index within the |
107 | * are the least significant bits of the node's dentry index within the |
116 | * parent directory node. |
108 | * parent directory node. |
117 | * |
109 | * |
118 | * The most significant half of the most significant half of all bits |
110 | * The most significant half of the most significant half of all bits |
119 | * are the least significant bits of the device handle. |
111 | * are the least significant bits of the device handle. |
120 | */ |
112 | */ |
121 | h = pfc & ((1 << (UPH_BUCKETS_LOG / 2)) - 1); |
113 | h = pfc & ((1 << (UPH_BUCKETS_LOG / 2)) - 1); |
122 | h |= (pdi & ((1 << (UPH_BUCKETS_LOG / 4)) - 1)) << |
114 | h |= (pdi & ((1 << (UPH_BUCKETS_LOG / 4)) - 1)) << |
123 | (UPH_BUCKETS_LOG / 2); |
115 | (UPH_BUCKETS_LOG / 2); |
124 | h |= (dev_handle & ((1 << (UPH_BUCKETS_LOG / 4)) - 1)) << |
116 | h |= (dev_handle & ((1 << (UPH_BUCKETS_LOG / 4)) - 1)) << |
125 | (3 * (UPH_BUCKETS_LOG / 4)); |
117 | (3 * (UPH_BUCKETS_LOG / 4)); |
126 | 118 | ||
127 | return h; |
119 | return h; |
128 | } |
120 | } |
129 | 121 | ||
130 | static int pos_compare(unsigned long key[], hash_count_t keys, link_t *item) |
122 | static int pos_compare(unsigned long key[], hash_count_t keys, link_t *item) |
131 | { |
123 | { |
132 | dev_handle_t dev_handle = (dev_handle_t)key[UPH_DH_KEY]; |
124 | dev_handle_t dev_handle = (dev_handle_t)key[UPH_DH_KEY]; |
133 | fat_cluster_t pfc = (fat_cluster_t)key[UPH_PFC_KEY]; |
125 | fat_cluster_t pfc = (fat_cluster_t)key[UPH_PFC_KEY]; |
134 | unsigned pdi = (unsigned)key[UPH_PDI_KEY]; |
126 | unsigned pdi = (unsigned)key[UPH_PDI_KEY]; |
135 | fat_idx_t *fidx = list_get_instance(item, fat_idx_t, uph_link); |
127 | fat_idx_t *fidx = list_get_instance(item, fat_idx_t, uph_link); |
136 | 128 | ||
137 | return (dev_handle == fidx->dev_handle) && (pfc == fidx->pfc) && |
129 | return (dev_handle == fidx->dev_handle) && (pfc == fidx->pfc) && |
138 | (pdi == fidx->pdi); |
130 | (pdi == fidx->pdi); |
139 | } |
131 | } |
140 | 132 | ||
141 | static void pos_remove_callback(link_t *item) |
133 | static void pos_remove_callback(link_t *item) |
142 | { |
134 | { |
143 | /* nothing to do */ |
135 | /* nothing to do */ |
144 | } |
136 | } |
145 | 137 | ||
146 | static hash_table_operations_t uph_ops = { |
138 | static hash_table_operations_t uph_ops = { |
147 | .hash = pos_hash, |
139 | .hash = pos_hash, |
148 | .compare = pos_compare, |
140 | .compare = pos_compare, |
149 | .remove_callback = pos_remove_callback, |
141 | .remove_callback = pos_remove_callback, |
150 | }; |
142 | }; |
151 | 143 | ||
152 | /** |
144 | /** |
153 | * Global hash table of all used fat_idx_t structures. |
145 | * Global hash table of all used fat_idx_t structures. |
154 | * The index structures are hashed by the dev_handle and index. |
146 | * The index structures are hashed by the dev_handle and index. |
155 | */ |
147 | */ |
156 | static hash_table_t ui_hash; |
148 | static hash_table_t ui_hash; |
157 | 149 | ||
158 | #define UIH_BUCKETS_LOG 12 |
150 | #define UIH_BUCKETS_LOG 12 |
159 | #define UIH_BUCKETS (1 << UIH_BUCKETS_LOG) |
151 | #define UIH_BUCKETS (1 << UIH_BUCKETS_LOG) |
160 | 152 | ||
161 | #define UIH_DH_KEY 0 |
153 | #define UIH_DH_KEY 0 |
162 | #define UIH_INDEX_KEY 1 |
154 | #define UIH_INDEX_KEY 1 |
163 | 155 | ||
164 | static hash_index_t idx_hash(unsigned long key[]) |
156 | static hash_index_t idx_hash(unsigned long key[]) |
165 | { |
157 | { |
166 | dev_handle_t dev_handle = (dev_handle_t)key[UIH_DH_KEY]; |
158 | dev_handle_t dev_handle = (dev_handle_t)key[UIH_DH_KEY]; |
167 | fs_index_t index = (fs_index_t)key[UIH_INDEX_KEY]; |
159 | fs_index_t index = (fs_index_t)key[UIH_INDEX_KEY]; |
168 | 160 | ||
169 | hash_index_t h; |
161 | hash_index_t h; |
170 | 162 | ||
171 | h = dev_handle & ((1 << (UIH_BUCKETS_LOG / 2)) - 1); |
163 | h = dev_handle & ((1 << (UIH_BUCKETS_LOG / 2)) - 1); |
172 | h |= (index & ((1 << (UIH_BUCKETS_LOG / 2)) - 1)) << |
164 | h |= (index & ((1 << (UIH_BUCKETS_LOG / 2)) - 1)) << |
173 | (UIH_BUCKETS_LOG / 2); |
165 | (UIH_BUCKETS_LOG / 2); |
174 | 166 | ||
175 | return h; |
167 | return h; |
176 | } |
168 | } |
177 | 169 | ||
178 | static int idx_compare(unsigned long key[], hash_count_t keys, link_t *item) |
170 | static int idx_compare(unsigned long key[], hash_count_t keys, link_t *item) |
179 | { |
171 | { |
180 | dev_handle_t dev_handle = (dev_handle_t)key[UIH_DH_KEY]; |
172 | dev_handle_t dev_handle = (dev_handle_t)key[UIH_DH_KEY]; |
181 | fs_index_t index = (fs_index_t)key[UIH_INDEX_KEY]; |
173 | fs_index_t index = (fs_index_t)key[UIH_INDEX_KEY]; |
182 | fat_idx_t *fidx = list_get_instance(item, fat_idx_t, uih_link); |
174 | fat_idx_t *fidx = list_get_instance(item, fat_idx_t, uih_link); |
183 | 175 | ||
184 | return (dev_handle == fidx->dev_handle) && (index == fidx->index); |
176 | return (dev_handle == fidx->dev_handle) && (index == fidx->index); |
185 | } |
177 | } |
186 | 178 | ||
187 | static void idx_remove_callback(link_t *item) |
179 | static void idx_remove_callback(link_t *item) |
188 | { |
180 | { |
189 | /* nothing to do */ |
181 | /* nothing to do */ |
190 | } |
182 | } |
191 | 183 | ||
192 | static hash_table_operations_t uih_ops = { |
184 | static hash_table_operations_t uih_ops = { |
193 | .hash = idx_hash, |
185 | .hash = idx_hash, |
194 | .compare = idx_compare, |
186 | .compare = idx_compare, |
195 | .remove_callback = idx_remove_callback, |
187 | .remove_callback = idx_remove_callback, |
196 | }; |
188 | }; |
197 | 189 | ||
198 | /** Allocate a VFS index which is not currently in use. */ |
190 | /** Allocate a VFS index which is not currently in use. */ |
199 | static bool fat_idx_alloc(dev_handle_t dev_handle, fs_index_t *index) |
191 | static bool fat_idx_alloc(dev_handle_t dev_handle, fs_index_t *index) |
200 | { |
192 | { |
201 | link_t *l; |
193 | link_t *l; |
202 | unused_t *u; |
194 | unused_t *u; |
203 | 195 | ||
204 | assert(index); |
196 | assert(index); |
205 | futex_down(&unused_futex); |
197 | futex_down(&unused_futex); |
206 | for (l = unused_head.next; l != &unused_head; l = l->next) { |
198 | for (l = unused_head.next; l != &unused_head; l = l->next) { |
207 | u = list_get_instance(l, unused_t, link); |
199 | u = list_get_instance(l, unused_t, link); |
208 | if (u->dev_handle == dev_handle) |
200 | if (u->dev_handle == dev_handle) |
209 | goto hit; |
201 | goto hit; |
210 | } |
202 | } |
211 | futex_up(&unused_futex); |
203 | futex_up(&unused_futex); |
212 | 204 | ||
213 | /* dev_handle not found */ |
205 | /* dev_handle not found */ |
214 | return false; |
206 | return false; |
215 | 207 | ||
216 | hit: |
208 | hit: |
217 | if (list_empty(&u->freed_head)) { |
209 | if (list_empty(&u->freed_head)) { |
218 | if (u->remaining) { |
210 | if (u->remaining) { |
219 | /* |
211 | /* |
220 | * There are no freed indices, allocate one directly |
212 | * There are no freed indices, allocate one directly |
221 | * from the counter. |
213 | * from the counter. |
222 | */ |
214 | */ |
223 | *index = u->next++; |
215 | *index = u->next++; |
224 | --u->remaining; |
216 | --u->remaining; |
225 | futex_up(&unused_futex); |
217 | futex_up(&unused_futex); |
226 | return true; |
218 | return true; |
227 | } |
219 | } |
228 | } else { |
220 | } else { |
229 | /* There are some freed indices which we can reuse. */ |
221 | /* There are some freed indices which we can reuse. */ |
230 | freed_t *f = list_get_instance(u->freed_head.next, freed_t, |
222 | freed_t *f = list_get_instance(u->freed_head.next, freed_t, |
231 | link); |
223 | link); |
232 | *index = f->first; |
224 | *index = f->first; |
233 | if (f->first++ == f->last) { |
225 | if (f->first++ == f->last) { |
234 | /* Destroy the interval. */ |
226 | /* Destroy the interval. */ |
235 | list_remove(&f->link); |
227 | list_remove(&f->link); |
236 | free(f); |
228 | free(f); |
237 | } |
229 | } |
238 | futex_up(&unused_futex); |
230 | futex_up(&unused_futex); |
239 | return true; |
231 | return true; |
240 | } |
232 | } |
241 | /* |
233 | /* |
242 | * We ran out of indices, which is extremely unlikely with FAT16, but |
234 | * We ran out of indices, which is extremely unlikely with FAT16, but |
243 | * theoretically still possible (e.g. too many open unlinked nodes or |
235 | * theoretically still possible (e.g. too many open unlinked nodes or |
244 | * too many zero-sized nodes). |
236 | * too many zero-sized nodes). |
245 | */ |
237 | */ |
246 | futex_up(&unused_futex); |
238 | futex_up(&unused_futex); |
247 | return false; |
239 | return false; |
248 | } |
240 | } |
249 | 241 | ||
250 | /** If possible, coalesce two intervals of freed indices. */ |
242 | /** If possible, coalesce two intervals of freed indices. */ |
251 | static void try_coalesce_intervals(link_t *l, link_t *r, link_t *cur) |
243 | static void try_coalesce_intervals(link_t *l, link_t *r, link_t *cur) |
252 | { |
244 | { |
253 | freed_t *fl = list_get_instance(l, freed_t, link); |
245 | freed_t *fl = list_get_instance(l, freed_t, link); |
254 | freed_t *fr = list_get_instance(r, freed_t, link); |
246 | freed_t *fr = list_get_instance(r, freed_t, link); |
255 | 247 | ||
256 | if (fl->last + 1 == fr->first) { |
248 | if (fl->last + 1 == fr->first) { |
257 | if (cur == l) { |
249 | if (cur == l) { |
258 | fl->last = fr->last; |
250 | fl->last = fr->last; |
259 | list_remove(r); |
251 | list_remove(r); |
260 | free(r); |
252 | free(r); |
261 | } else { |
253 | } else { |
262 | fr->first = fl->first; |
254 | fr->first = fl->first; |
263 | list_remove(l); |
255 | list_remove(l); |
264 | free(l); |
256 | free(l); |
265 | } |
257 | } |
266 | } |
258 | } |
267 | } |
259 | } |
268 | 260 | ||
269 | /** Free a VFS index, which is no longer in use. */ |
261 | /** Free a VFS index, which is no longer in use. */ |
270 | static void fat_idx_free(dev_handle_t dev_handle, fs_index_t index) |
262 | static void fat_idx_free(dev_handle_t dev_handle, fs_index_t index) |
271 | { |
263 | { |
272 | link_t *l; |
264 | link_t *l; |
273 | unused_t *u; |
265 | unused_t *u; |
274 | 266 | ||
275 | futex_down(&unused_futex); |
267 | futex_down(&unused_futex); |
276 | for (l = unused_head.next; l != &unused_head; l = l->next) { |
268 | for (l = unused_head.next; l != &unused_head; l = l->next) { |
277 | u = list_get_instance(l, unused_t, link); |
269 | u = list_get_instance(l, unused_t, link); |
278 | if (u->dev_handle == dev_handle) |
270 | if (u->dev_handle == dev_handle) |
279 | goto hit; |
271 | goto hit; |
280 | } |
272 | } |
281 | futex_up(&unused_futex); |
273 | futex_up(&unused_futex); |
282 | 274 | ||
283 | /* should not happen */ |
275 | /* should not happen */ |
284 | assert(0); |
276 | assert(0); |
285 | 277 | ||
286 | hit: |
278 | hit: |
287 | if (u->next == index + 1) { |
279 | if (u->next == index + 1) { |
288 | /* The index can be returned directly to the counter. */ |
280 | /* The index can be returned directly to the counter. */ |
289 | u->next--; |
281 | u->next--; |
290 | u->remaining++; |
282 | u->remaining++; |
291 | } else { |
283 | } else { |
292 | /* |
284 | /* |
293 | * The index must be returned either to an existing freed |
285 | * The index must be returned either to an existing freed |
294 | * interval or a new interval must be created. |
286 | * interval or a new interval must be created. |
295 | */ |
287 | */ |
296 | link_t *lnk; |
288 | link_t *lnk; |
297 | freed_t *n; |
289 | freed_t *n; |
298 | for (lnk = u->freed_head.next; lnk != &u->freed_head; |
290 | for (lnk = u->freed_head.next; lnk != &u->freed_head; |
299 | lnk = lnk->next) { |
291 | lnk = lnk->next) { |
300 | freed_t *f = list_get_instance(lnk, freed_t, link); |
292 | freed_t *f = list_get_instance(lnk, freed_t, link); |
301 | if (f->first == index + 1) { |
293 | if (f->first == index + 1) { |
302 | f->first--; |
294 | f->first--; |
303 | if (lnk->prev != &u->freed_head) |
295 | if (lnk->prev != &u->freed_head) |
304 | try_coalesce_intervals(lnk->prev, lnk, |
296 | try_coalesce_intervals(lnk->prev, lnk, |
305 | lnk); |
297 | lnk); |
306 | futex_up(&unused_futex); |
298 | futex_up(&unused_futex); |
307 | return; |
299 | return; |
308 | } |
300 | } |
309 | if (f->last == index - 1) { |
301 | if (f->last == index - 1) { |
310 | f->last++; |
302 | f->last++; |
311 | if (lnk->next != &u->freed_head) |
303 | if (lnk->next != &u->freed_head) |
312 | try_coalesce_intervals(lnk, lnk->next, |
304 | try_coalesce_intervals(lnk, lnk->next, |
313 | lnk); |
305 | lnk); |
314 | futex_up(&unused_futex); |
306 | futex_up(&unused_futex); |
315 | return; |
307 | return; |
316 | } |
308 | } |
317 | if (index > f->first) { |
309 | if (index > f->first) { |
318 | n = malloc(sizeof(freed_t)); |
310 | n = malloc(sizeof(freed_t)); |
319 | /* TODO: sleep until allocation succeeds */ |
311 | /* TODO: sleep until allocation succeeds */ |
320 | assert(n); |
312 | assert(n); |
321 | link_initialize(&n->link); |
313 | link_initialize(&n->link); |
322 | n->first = index; |
314 | n->first = index; |
323 | n->last = index; |
315 | n->last = index; |
324 | list_insert_before(&n->link, lnk); |
316 | list_insert_before(&n->link, lnk); |
325 | futex_up(&unused_futex); |
317 | futex_up(&unused_futex); |
326 | return; |
318 | return; |
327 | } |
319 | } |
328 | 320 | ||
329 | } |
321 | } |
330 | /* The index will form the last interval. */ |
322 | /* The index will form the last interval. */ |
331 | n = malloc(sizeof(freed_t)); |
323 | n = malloc(sizeof(freed_t)); |
332 | /* TODO: sleep until allocation succeeds */ |
324 | /* TODO: sleep until allocation succeeds */ |
333 | assert(n); |
325 | assert(n); |
334 | link_initialize(&n->link); |
326 | link_initialize(&n->link); |
335 | n->first = index; |
327 | n->first = index; |
336 | n->last = index; |
328 | n->last = index; |
337 | list_append(&n->link, &u->freed_head); |
329 | list_append(&n->link, &u->freed_head); |
338 | } |
330 | } |
339 | futex_up(&unused_futex); |
331 | futex_up(&unused_futex); |
340 | } |
332 | } |
341 | 333 | ||
342 | fat_idx_t * |
334 | fat_idx_t * |
343 | fat_idx_get_by_pos(dev_handle_t dev_handle, fat_cluster_t pfc, unsigned pdi) |
335 | fat_idx_get_by_pos(dev_handle_t dev_handle, fat_cluster_t pfc, unsigned pdi) |
344 | { |
336 | { |
345 | fat_idx_t *fidx; |
337 | fat_idx_t *fidx; |
346 | link_t *l; |
338 | link_t *l; |
347 | unsigned long pkey[] = { |
339 | unsigned long pkey[] = { |
348 | [UPH_DH_KEY] = dev_handle, |
340 | [UPH_DH_KEY] = dev_handle, |
349 | [UPH_PFC_KEY] = pfc, |
341 | [UPH_PFC_KEY] = pfc, |
350 | [UPH_PDI_KEY] = pdi, |
342 | [UPH_PDI_KEY] = pdi, |
351 | }; |
343 | }; |
352 | 344 | ||
353 | futex_down(&used_futex); |
345 | futex_down(&used_futex); |
354 | l = hash_table_find(&up_hash, pkey); |
346 | l = hash_table_find(&up_hash, pkey); |
355 | futex_up(&used_futex); |
- | |
356 | if (l) { |
347 | if (l) { |
357 | fidx = hash_table_get_instance(l, fat_idx_t, uph_link); |
348 | fidx = hash_table_get_instance(l, fat_idx_t, uph_link); |
358 | } else { |
349 | } else { |
359 | fidx = (fat_idx_t *) malloc(sizeof(fat_idx_t)); |
350 | fidx = (fat_idx_t *) malloc(sizeof(fat_idx_t)); |
360 | if (!fidx) { |
351 | if (!fidx) { |
- | 352 | futex_up(&used_futex); |
|
361 | return NULL; |
353 | return NULL; |
362 | } |
354 | } |
363 | if (!fat_idx_alloc(dev_handle, &fidx->index)) { |
355 | if (!fat_idx_alloc(dev_handle, &fidx->index)) { |
364 | free(fidx); |
356 | free(fidx); |
- | 357 | futex_up(&used_futex); |
|
365 | return NULL; |
358 | return NULL; |
366 | } |
359 | } |
367 | 360 | ||
368 | unsigned long ikey[] = { |
361 | unsigned long ikey[] = { |
369 | [UIH_DH_KEY] = dev_handle, |
362 | [UIH_DH_KEY] = dev_handle, |
370 | [UIH_INDEX_KEY] = fidx->index, |
363 | [UIH_INDEX_KEY] = fidx->index, |
371 | }; |
364 | }; |
372 | 365 | ||
373 | link_initialize(&fidx->uph_link); |
366 | link_initialize(&fidx->uph_link); |
374 | link_initialize(&fidx->uih_link); |
367 | link_initialize(&fidx->uih_link); |
- | 368 | futex_initialize(&fidx->lock, 1); |
|
375 | fidx->dev_handle = dev_handle; |
369 | fidx->dev_handle = dev_handle; |
376 | fidx->pfc = pfc; |
370 | fidx->pfc = pfc; |
377 | fidx->pdi = pdi; |
371 | fidx->pdi = pdi; |
378 | fidx->nodep = NULL; |
372 | fidx->nodep = NULL; |
379 | 373 | ||
380 | futex_down(&used_futex); |
- | |
381 | hash_table_insert(&up_hash, pkey, &fidx->uph_link); |
374 | hash_table_insert(&up_hash, pkey, &fidx->uph_link); |
382 | hash_table_insert(&ui_hash, ikey, &fidx->uih_link); |
375 | hash_table_insert(&ui_hash, ikey, &fidx->uih_link); |
383 | futex_up(&used_futex); |
- | |
384 | } |
376 | } |
- | 377 | futex_down(&fidx->lock); |
|
- | 378 | futex_up(&used_futex); |
|
385 | 379 | ||
386 | return fidx; |
380 | return fidx; |
387 | } |
381 | } |
388 | 382 | ||
389 | fat_idx_t * |
383 | fat_idx_t * |
390 | fat_idx_get_by_index(dev_handle_t dev_handle, fs_index_t index) |
384 | fat_idx_get_by_index(dev_handle_t dev_handle, fs_index_t index) |
391 | { |
385 | { |
392 | fat_idx_t *fidx = NULL; |
386 | fat_idx_t *fidx = NULL; |
393 | link_t *l; |
387 | link_t *l; |
394 | unsigned long ikey[] = { |
388 | unsigned long ikey[] = { |
395 | [UIH_DH_KEY] = dev_handle, |
389 | [UIH_DH_KEY] = dev_handle, |
396 | [UIH_INDEX_KEY] = index, |
390 | [UIH_INDEX_KEY] = index, |
397 | }; |
391 | }; |
398 | 392 | ||
399 | futex_down(&used_futex); |
393 | futex_down(&used_futex); |
400 | l = hash_table_find(&ui_hash, ikey); |
394 | l = hash_table_find(&ui_hash, ikey); |
401 | futex_up(&used_futex); |
- | |
402 | if (l) { |
395 | if (l) { |
403 | fidx = hash_table_get_instance(l, fat_idx_t, uih_link); |
396 | fidx = hash_table_get_instance(l, fat_idx_t, uih_link); |
- | 397 | futex_down(&fidx->lock); |
|
404 | } |
398 | } |
- | 399 | futex_up(&used_futex); |
|
405 | 400 | ||
406 | return fidx; |
401 | return fidx; |
407 | } |
402 | } |
408 | 403 | ||
409 | 404 |