1 /*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright © 2001-2007 Red Hat, Inc.
5 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
6 *
7 * Created by David Woodhouse <dwmw2@infradead.org>
8 *
9 * For licensing information, see the file 'LICENCE' in this directory.
10 *
11 */
12
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/kernel.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/vmalloc.h>
19 #include <linux/mtd/mtd.h>
20 #include <linux/mm.h> /* kvfree() */
21 #include "nodelist.h"
22
23 static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *,
24 struct jffs2_inode_cache *, struct jffs2_full_dirent **);
25
26 static inline struct jffs2_inode_cache *
27 first_inode_chain(int *i, struct jffs2_sb_info *c)
28 {
29 for (; *i < c->inocache_hashsize; (*i)++) {
30 if (c->inocache_list[*i])
31 return c->inocache_list[*i];
32 }
33 return NULL;
34 }
35
36 static inline struct jffs2_inode_cache *
37 next_inode(int *i, struct jffs2_inode_cache *ic, struct jffs2_sb_info *c)
38 {
39 /* More in this chain? */
40 if (ic->next)
41 return ic->next;
42 (*i)++;
43 return first_inode_chain(i, c);
44 }
45
46 #define for_each_inode(i, c, ic) \
47 for (i = 0, ic = first_inode_chain(&i, (c)); \
48 ic; \
49 ic = next_inode(&i, ic, (c)))
50
51
52 static void jffs2_build_inode_pass1(struct jffs2_sb_info *c,
53 struct jffs2_inode_cache *ic,
54 int *dir_hardlinks)
55 {
56 struct jffs2_full_dirent *fd;
57
58 dbg_fsbuild("building directory inode #%u\n", ic->ino);
59
60 /* For each child, increase nlink */
61 for(fd = ic->scan_dents; fd; fd = fd->next) {
62 struct jffs2_inode_cache *child_ic;
63 if (!fd->ino)
64 continue;
65
66 /* we can get high latency here with huge directories */
67
68 child_ic = jffs2_get_ino_cache(c, fd->ino);
69 if (!child_ic) {
70 dbg_fsbuild("child \"%s\" (ino #%u) of dir ino #%u doesn't exist!\n",
71 fd->name, fd->ino, ic->ino);
72 jffs2_mark_node_obsolete(c, fd->raw);
73 /* Clear the ic/raw union so it doesn't cause problems later. */
74 fd->ic = NULL;
75 continue;
76 }
77
78 /* From this point, fd->raw is no longer used so we can set fd->ic */
79 fd->ic = child_ic;
80 child_ic->pino_nlink++;
81 /* If we appear (at this stage) to have hard-linked directories,
82 * set a flag to trigger a scan later */
83 if (fd->type == DT_DIR) {
84 child_ic->flags |= INO_FLAGS_IS_DIR;
85 if (child_ic->pino_nlink > 1)
86 *dir_hardlinks = 1;
87 }
88
89 dbg_fsbuild("increased nlink for child \"%s\" (ino #%u)\n", fd->name, fd->ino);
90 /* Can't free scan_dents so far. We might need them in pass 2 */
91 }
92 }
93
94 /* Scan plan:
95 - Scan physical nodes. Build map of inodes/dirents. Allocate inocaches as we go
96 - Scan directory tree from top down, setting nlink in inocaches
97 - Scan inocaches for inodes with nlink==0
98 */
99 static int jffs2_build_filesystem(struct jffs2_sb_info *c)
100 {
101 int ret, i, dir_hardlinks = 0;
102 struct jffs2_inode_cache *ic;
103 struct jffs2_full_dirent *fd;
104 struct jffs2_full_dirent *dead_fds = NULL;
105
106 dbg_fsbuild("build FS data structures\n");
107
108 /* First, scan the medium and build all the inode caches with
109 lists of physical nodes */
110
111 c->flags |= JFFS2_SB_FLAG_SCANNING;
112 ret = jffs2_scan_medium(c);
113 c->flags &= ~JFFS2_SB_FLAG_SCANNING;
114 if (ret)
115 goto exit;
116
117 dbg_fsbuild("scanned flash completely\n");
118 jffs2_dbg_dump_block_lists_nolock(c);
119
120 dbg_fsbuild("pass 1 starting\n");
121 c->flags |= JFFS2_SB_FLAG_BUILDING;
122 /* Now scan the directory tree, increasing nlink according to every dirent found. */
123 for_each_inode(i, c, ic) {
124 if (ic->scan_dents) {
125 jffs2_build_inode_pass1(c, ic, &dir_hardlinks);
126 cond_resched();
127 }
128 }
129
130 dbg_fsbuild("pass 1 complete\n");
131
132 /* Next, scan for inodes with nlink == 0 and remove them. If
133 they were directories, then decrement the nlink of their
134 children too, and repeat the scan. As that's going to be
135 a fairly uncommon occurrence, it's not so evil to do it this
136 way. Recursion bad. */
137 dbg_fsbuild("pass 2 starting\n");
138
139 for_each_inode(i, c, ic) {
140 if (ic->pino_nlink)
141 continue;
142
143 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
144 cond_resched();
145 }
146
147 dbg_fsbuild("pass 2a starting\n");
148
149 while (dead_fds) {
150 fd = dead_fds;
151 dead_fds = fd->next;
152
153 ic = jffs2_get_ino_cache(c, fd->ino);
154
155 if (ic)
156 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
157 jffs2_free_full_dirent(fd);
158 }
159
160 dbg_fsbuild("pass 2a complete\n");
161
162 if (dir_hardlinks) {
163 /* If we detected directory hardlinks earlier, *hopefully*
164 * they are gone now because some of the links were from
165 * dead directories which still had some old dirents lying
166 * around and not yet garbage-collected, but which have
167 * been discarded above. So clear the pino_nlink field
168 * in each directory, so that the final scan below can
169 * print appropriate warnings. */
170 for_each_inode(i, c, ic) {
171 if (ic->flags & INO_FLAGS_IS_DIR)
172 ic->pino_nlink = 0;
173 }
174 }
175 dbg_fsbuild("freeing temporary data structures\n");
176
177 /* Finally, we can scan again and free the dirent structs */
178 for_each_inode(i, c, ic) {
179 while(ic->scan_dents) {
180 fd = ic->scan_dents;
181 ic->scan_dents = fd->next;
182 /* We do use the pino_nlink field to count nlink of
183 * directories during fs build, so set it to the
184 * parent ino# now. Now that there's hopefully only
185 * one. */
186 if (fd->type == DT_DIR) {
187 if (!fd->ic) {
188 /* We'll have complained about it and marked the coresponding
189 raw node obsolete already. Just skip it. */
190 continue;
191 }
192
193 /* We *have* to have set this in jffs2_build_inode_pass1() */
194 BUG_ON(!(fd->ic->flags & INO_FLAGS_IS_DIR));
195
196 /* We clear ic->pino_nlink ∀ directories' ic *only* if dir_hardlinks
197 * is set. Otherwise, we know this should never trigger anyway, so
198 * we don't do the check. And ic->pino_nlink still contains the nlink
199 * value (which is 1). */
200 if (dir_hardlinks && fd->ic->pino_nlink) {
201 JFFS2_ERROR("child dir \"%s\" (ino #%u) of dir ino #%u is also hard linked from dir ino #%u\n",
202 fd->name, fd->ino, ic->ino, fd->ic->pino_nlink);
203 /* Should we unlink it from its previous parent? */
204 }
205
206 /* For directories, ic->pino_nlink holds that parent inode # */
207 fd->ic->pino_nlink = ic->ino;
208 }
209 jffs2_free_full_dirent(fd);
210 }
211 ic->scan_dents = NULL;
212 cond_resched();
213 }
214 ret = jffs2_build_xattr_subsystem(c);
215 if (ret)
216 goto exit;
217
218 c->flags &= ~JFFS2_SB_FLAG_BUILDING;
219
220 dbg_fsbuild("FS build complete\n");
221
222 /* Rotate the lists by some number to ensure wear levelling */
223 jffs2_rotate_lists(c);
224
225 ret = 0;
226
227 exit:
228 if (ret) {
229 for_each_inode(i, c, ic) {
230 while(ic->scan_dents) {
231 fd = ic->scan_dents;
232 ic->scan_dents = fd->next;
233 jffs2_free_full_dirent(fd);
234 }
235 }
236 jffs2_clear_xattr_subsystem(c);
237 }
238
239 return ret;
240 }
241
242 static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c,
243 struct jffs2_inode_cache *ic,
244 struct jffs2_full_dirent **dead_fds)
245 {
246 struct jffs2_raw_node_ref *raw;
247 struct jffs2_full_dirent *fd;
248
249 dbg_fsbuild("removing ino #%u with nlink == zero.\n", ic->ino);
250
251 raw = ic->nodes;
252 while (raw != (void *)ic) {
253 struct jffs2_raw_node_ref *next = raw->next_in_ino;
254 dbg_fsbuild("obsoleting node at 0x%08x\n", ref_offset(raw));
255 jffs2_mark_node_obsolete(c, raw);
256 raw = next;
257 }
258
259 if (ic->scan_dents) {
260 int whinged = 0;
261 dbg_fsbuild("inode #%u was a directory which may have children...\n", ic->ino);
262
263 while(ic->scan_dents) {
264 struct jffs2_inode_cache *child_ic;
265
266 fd = ic->scan_dents;
267 ic->scan_dents = fd->next;
268
269 if (!fd->ino) {
270 /* It's a deletion dirent. Ignore it */
271 dbg_fsbuild("child \"%s\" is a deletion dirent, skipping...\n", fd->name);
272 jffs2_free_full_dirent(fd);
273 continue;
274 }
275 if (!whinged)
276 whinged = 1;
277
278 dbg_fsbuild("removing child \"%s\", ino #%u\n", fd->name, fd->ino);
279
280 child_ic = jffs2_get_ino_cache(c, fd->ino);
281 if (!child_ic) {
282 dbg_fsbuild("cannot remove child \"%s\", ino #%u, because it doesn't exist\n",
283 fd->name, fd->ino);
284 jffs2_free_full_dirent(fd);
285 continue;
286 }
287
288 /* Reduce nlink of the child. If it's now zero, stick it on the
289 dead_fds list to be cleaned up later. Else just free the fd */
290 child_ic->pino_nlink--;
291
292 if (!child_ic->pino_nlink) {
293 dbg_fsbuild("inode #%u (\"%s\") now has no links; adding to dead_fds list.\n",
294 fd->ino, fd->name);
295 fd->next = *dead_fds;
296 *dead_fds = fd;
297 } else {
298 dbg_fsbuild("inode #%u (\"%s\") has now got nlink %d. Ignoring.\n",
299 fd->ino, fd->name, child_ic->pino_nlink);
300 jffs2_free_full_dirent(fd);
301 }
302 }
303 }
304
305 /*
306 We don't delete the inocache from the hash list and free it yet.
307 The erase code will do that, when all the nodes are completely gone.
308 */
309 }
310
311 static void jffs2_calc_trigger_levels(struct jffs2_sb_info *c)
312 {
313 uint32_t size;
314
315 /* Deletion should almost _always_ be allowed. We're fairly
316 buggered once we stop allowing people to delete stuff
317 because there's not enough free space... */
318 c->resv_blocks_deletion = 2;
319
320 /* Be conservative about how much space we need before we allow writes.
321 On top of that which is required for deletia, require an extra 2%
322 of the medium to be available, for overhead caused by nodes being
323 split across blocks, etc. */
324
325 size = c->flash_size / 50; /* 2% of flash size */
326 size += c->nr_blocks * 100; /* And 100 bytes per eraseblock */
327 size += c->sector_size - 1; /* ... and round up */
328
329 c->resv_blocks_write = c->resv_blocks_deletion + (size / c->sector_size);
330
331 /* When do we let the GC thread run in the background */
332
333 c->resv_blocks_gctrigger = c->resv_blocks_write + 1;
334
335 /* When do we allow garbage collection to merge nodes to make
336 long-term progress at the expense of short-term space exhaustion? */
337 c->resv_blocks_gcmerge = c->resv_blocks_deletion + 1;
338
339 /* When do we allow garbage collection to eat from bad blocks rather
340 than actually making progress? */
341 c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2;
342
343 /* What number of 'very dirty' eraseblocks do we allow before we
344 trigger the GC thread even if we don't _need_ the space. When we
345 can't mark nodes obsolete on the medium, the old dirty nodes cause
346 performance problems because we have to inspect and discard them. */
347 c->vdirty_blocks_gctrigger = c->resv_blocks_gctrigger;
348 if (jffs2_can_mark_obsolete(c))
349 c->vdirty_blocks_gctrigger *= 10;
350
351 /* If there's less than this amount of dirty space, don't bother
352 trying to GC to make more space. It'll be a fruitless task */
353 c->nospc_dirty_size = c->sector_size + (c->flash_size / 100);
354
355 dbg_fsbuild("trigger levels (size %d KiB, block size %d KiB, %d blocks)\n",
356 c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks);
357 dbg_fsbuild("Blocks required to allow deletion: %d (%d KiB)\n",
358 c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024);
359 dbg_fsbuild("Blocks required to allow writes: %d (%d KiB)\n",
360 c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024);
361 dbg_fsbuild("Blocks required to quiesce GC thread: %d (%d KiB)\n",
362 c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024);
363 dbg_fsbuild("Blocks required to allow GC merges: %d (%d KiB)\n",
364 c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024);
365 dbg_fsbuild("Blocks required to GC bad blocks: %d (%d KiB)\n",
366 c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024);
367 dbg_fsbuild("Amount of dirty space required to GC: %d bytes\n",
368 c->nospc_dirty_size);
369 dbg_fsbuild("Very dirty blocks before GC triggered: %d\n",
370 c->vdirty_blocks_gctrigger);
371 }
372
373 int jffs2_do_mount_fs(struct jffs2_sb_info *c)
374 {
375 int ret;
376 int i;
377 int size;
378
379 c->free_size = c->flash_size;
380 c->nr_blocks = c->flash_size / c->sector_size;
381 size = sizeof(struct jffs2_eraseblock) * c->nr_blocks;
382 #ifndef __ECOS
383 if (jffs2_blocks_use_vmalloc(c))
384 c->blocks = vzalloc(size);
385 else
386 #endif
387 c->blocks = kzalloc(size, GFP_KERNEL);
388 if (!c->blocks)
389 return -ENOMEM;
390
391 for (i=0; i<c->nr_blocks; i++) {
392 INIT_LIST_HEAD(&c->blocks[i].list);
393 c->blocks[i].offset = i * c->sector_size;
394 c->blocks[i].free_size = c->sector_size;
395 }
396
397 INIT_LIST_HEAD(&c->clean_list);
398 INIT_LIST_HEAD(&c->very_dirty_list);
399 INIT_LIST_HEAD(&c->dirty_list);
400 INIT_LIST_HEAD(&c->erasable_list);
401 INIT_LIST_HEAD(&c->erasing_list);
402 INIT_LIST_HEAD(&c->erase_checking_list);
403 INIT_LIST_HEAD(&c->erase_pending_list);
404 INIT_LIST_HEAD(&c->erasable_pending_wbuf_list);
405 INIT_LIST_HEAD(&c->erase_complete_list);
406 INIT_LIST_HEAD(&c->free_list);
407 INIT_LIST_HEAD(&c->bad_list);
408 INIT_LIST_HEAD(&c->bad_used_list);
409 c->highest_ino = 1;
410 c->summary = NULL;
411
412 ret = jffs2_sum_init(c);
413 if (ret)
414 goto out_free;
415
416 if (jffs2_build_filesystem(c)) {
417 dbg_fsbuild("build_fs failed\n");
418 jffs2_free_ino_caches(c);
419 jffs2_free_raw_node_refs(c);
420 ret = -EIO;
421 goto out_sum_exit;
422 }
423
424 jffs2_calc_trigger_levels(c);
425
426 return 0;
427
428 out_sum_exit:
429 jffs2_sum_exit(c);
430 out_free:
431 kvfree(c->blocks);
432
433 return ret;
434 }
435
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