aboutsummaryrefslogtreecommitdiffstats
path: root/fs/jffs2/build.c
blob: a01dd5fdbb95f4280dd3f8900e8e8a43277bc20a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright (C) 2001-2003 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 * $Id: build.c,v 1.69 2004/12/16 20:22:18 dmarlin Exp $
 *
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mtd/mtd.h>
#include "nodelist.h"

static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *, struct jffs2_inode_cache *, struct jffs2_full_dirent **);

static inline struct jffs2_inode_cache *
first_inode_chain(int *i, struct jffs2_sb_info *c)
{
	for (; *i < INOCACHE_HASHSIZE; (*i)++) {
		if (c->inocache_list[*i])
			return c->inocache_list[*i];
	}
	return NULL;
}

static inline struct jffs2_inode_cache *
next_inode(int *i, struct jffs2_inode_cache *ic, struct jffs2_sb_info *c)
{
	/* More in this chain? */
	if (ic->next)
		return ic->next;
	(*i)++;
	return first_inode_chain(i, c);
}

#define for_each_inode(i, c, ic)			\
	for (i = 0, ic = first_inode_chain(&i, (c));	\
	     ic;					\
	     ic = next_inode(&i, ic, (c)))


static inline void jffs2_build_inode_pass1(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
{
	struct jffs2_full_dirent *fd;

	D1(printk(KERN_DEBUG "jffs2_build_inode building directory inode #%u\n", ic->ino));

	/* For each child, increase nlink */
	for(fd = ic->scan_dents; fd; fd = fd->next) {
		struct jffs2_inode_cache *child_ic;
		if (!fd->ino)
			continue;

		/* XXX: Can get high latency here with huge directories */

		child_ic = jffs2_get_ino_cache(c, fd->ino);
		if (!child_ic) {
			printk(KERN_NOTICE "Eep. Child \"%s\" (ino #%u) of dir ino #%u doesn't exist!\n",
				  fd->name, fd->ino, ic->ino);
			jffs2_mark_node_obsolete(c, fd->raw);
			continue;
		}

		if (child_ic->nlink++ && fd->type == DT_DIR) {
			printk(KERN_NOTICE "Child dir \"%s\" (ino #%u) of dir ino #%u appears to be a hard link\n", fd->name, fd->ino, ic->ino);
			if (fd->ino == 1 && ic->ino == 1) {
				printk(KERN_NOTICE "This is mostly harmless, and probably caused by creating a JFFS2 image\n");
				printk(KERN_NOTICE "using a buggy version of mkfs.jffs2. Use at least v1.17.\n");
			}
			/* What do we do about it? */
		}
		D1(printk(KERN_DEBUG "Increased nlink for child \"%s\" (ino #%u)\n", fd->name, fd->ino));
		/* Can't free them. We might need them in pass 2 */
	}
}

/* Scan plan:
 - Scan physical nodes. Build map of inodes/dirents. Allocate inocaches as we go
 - Scan directory tree from top down, setting nlink in inocaches
 - Scan inocaches for inodes with nlink==0
*/
static int jffs2_build_filesystem(struct jffs2_sb_info *c)
{
	int ret;
	int i;
	struct jffs2_inode_cache *ic;
	struct jffs2_full_dirent *fd;
	struct jffs2_full_dirent *dead_fds = NULL;

	/* First, scan the medium and build all the inode caches with
	   lists of physical nodes */

	c->flags |= JFFS2_SB_FLAG_MOUNTING;
	ret = jffs2_scan_medium(c);
	if (ret)
		goto exit;

	D1(printk(KERN_DEBUG "Scanned flash completely\n"));
	D2(jffs2_dump_block_lists(c));

	/* Now scan the directory tree, increasing nlink according to every dirent found. */
	for_each_inode(i, c, ic) {
		D1(printk(KERN_DEBUG "Pass 1: ino #%u\n", ic->ino));

		D1(BUG_ON(ic->ino > c->highest_ino));

		if (ic->scan_dents) {
			jffs2_build_inode_pass1(c, ic);
			cond_resched();
		}
	}
	c->flags &= ~JFFS2_SB_FLAG_MOUNTING;

	D1(printk(KERN_DEBUG "Pass 1 complete\n"));

	/* Next, scan for inodes with nlink == 0 and remove them. If
	   they were directories, then decrement the nlink of their
	   children too, and repeat the scan. As that's going to be
	   a fairly uncommon occurrence, it's not so evil to do it this
	   way. Recursion bad. */
	D1(printk(KERN_DEBUG "Pass 2 starting\n"));

	for_each_inode(i, c, ic) {
		D1(printk(KERN_DEBUG "Pass 2: ino #%u, nlink %d, ic %p, nodes %p\n", ic->ino, ic->nlink, ic, ic->nodes));
		if (ic->nlink)
			continue;
			
		jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
		cond_resched();
	} 

	D1(printk(KERN_DEBUG "Pass 2a starting\n"));

	while (dead_fds) {
		fd = dead_fds;
		dead_fds = fd->next;

		ic = jffs2_get_ino_cache(c, fd->ino);
		D1(printk(KERN_DEBUG "Removing dead_fd ino #%u (\"%s\"), ic at %p\n", fd->ino, fd->name, ic));

		if (ic)
			jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
		jffs2_free_full_dirent(fd);
	}

	D1(printk(KERN_DEBUG "Pass 2 complete\n"));
	
	/* Finally, we can scan again and free the dirent structs */
	for_each_inode(i, c, ic) {
		D1(printk(KERN_DEBUG "Pass 3: ino #%u, ic %p, nodes %p\n", ic->ino, ic, ic->nodes));

		while(ic->scan_dents) {
			fd = ic->scan_dents;
			ic->scan_dents = fd->next;
			jffs2_free_full_dirent(fd);
		}
		ic->scan_dents = NULL;
		cond_resched();
	}
	D1(printk(KERN_DEBUG "Pass 3 complete\n"));
	D2(jffs2_dump_block_lists(c));

	/* Rotate the lists by some number to ensure wear levelling */
	jffs2_rotate_lists(c);

	ret = 0;

exit:
	if (ret) {
		for_each_inode(i, c, ic) {
			while(ic->scan_dents) {
				fd = ic->scan_dents;
				ic->scan_dents = fd->next;
				jffs2_free_full_dirent(fd);
			}
		}
	}

	return ret;
}

static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic, struct jffs2_full_dirent **dead_fds)
{
	struct jffs2_raw_node_ref *raw;
	struct jffs2_full_dirent *fd;

	D1(printk(KERN_DEBUG "JFFS2: Removing ino #%u with nlink == zero.\n", ic->ino));
	
	raw = ic->nodes;
	while (raw != (void *)ic) {
		struct jffs2_raw_node_ref *next = raw->next_in_ino;
		D1(printk(KERN_DEBUG "obsoleting node at 0x%08x\n", ref_offset(raw)));
		jffs2_mark_node_obsolete(c, raw);
		raw = next;
	}

	if (ic->scan_dents) {
		int whinged = 0;
		D1(printk(KERN_DEBUG "Inode #%u was a directory which may have children...\n", ic->ino));

		while(ic->scan_dents) {
			struct jffs2_inode_cache *child_ic;

			fd = ic->scan_dents;
			ic->scan_dents = fd->next;

			if (!fd->ino) {
				/* It's a deletion dirent. Ignore it */
				D1(printk(KERN_DEBUG "Child \"%s\" is a deletion dirent, skipping...\n", fd->name));
				jffs2_free_full_dirent(fd);
				continue;
			}
			if (!whinged) {
				whinged = 1;
				printk(KERN_NOTICE "Inode #%u was a directory with children - removing those too...\n", ic->ino);
			}

			D1(printk(KERN_DEBUG "Removing child \"%s\", ino #%u\n",
				  fd->name, fd->ino));
			
			child_ic = jffs2_get_ino_cache(c, fd->ino);
			if (!child_ic) {
				printk(KERN_NOTICE "Cannot remove child \"%s\", ino #%u, because it doesn't exist\n", fd->name, fd->ino);
				jffs2_free_full_dirent(fd);
				continue;
			}

			/* Reduce nlink of the child. If it's now zero, stick it on the 
			   dead_fds list to be cleaned up later. Else just free the fd */

			child_ic->nlink--;
			
			if (!child_ic->nlink) {
				D1(printk(KERN_DEBUG "Inode #%u (\"%s\") has now got zero nlink. Adding to dead_fds list.\n",
					  fd->ino, fd->name));
				fd->next = *dead_fds;
				*dead_fds = fd;
			} else {
				D1(printk(KERN_DEBUG "Inode #%u (\"%s\") has now got nlink %d. Ignoring.\n",
					  fd->ino, fd->name, child_ic->nlink));
				jffs2_free_full_dirent(fd);
			}
		}
	}

	/*
	   We don't delete the inocache from the hash list and free it yet. 
	   The erase code will do that, when all the nodes are completely gone.
	*/
}

static void jffs2_calc_trigger_levels(struct jffs2_sb_info *c)
{
	uint32_t size;

	/* Deletion should almost _always_ be allowed. We're fairly
	   buggered once we stop allowing people to delete stuff
	   because there's not enough free space... */
	c->resv_blocks_deletion = 2;

	/* Be conservative about how much space we need before we allow writes. 
	   On top of that which is required for deletia, require an extra 2%
	   of the medium to be available, for overhead caused by nodes being
	   split across blocks, etc. */

	size = c->flash_size / 50; /* 2% of flash size */
	size += c->nr_blocks * 100; /* And 100 bytes per eraseblock */
	size += c->sector_size - 1; /* ... and round up */

	c->resv_blocks_write = c->resv_blocks_deletion + (size / c->sector_size);

	/* When do we let the GC thread run in the background */

	c->resv_blocks_gctrigger = c->resv_blocks_write + 1;

	/* When do we allow garbage collection to merge nodes to make 
	   long-term progress at the expense of short-term space exhaustion? */
	c->resv_blocks_gcmerge = c->resv_blocks_deletion + 1;

	/* When do we allow garbage collection to eat from bad blocks rather
	   than actually making progress? */
	c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2;

	/* If there's less than this amount of dirty space, don't bother
	   trying to GC to make more space. It'll be a fruitless task */
	c->nospc_dirty_size = c->sector_size + (c->flash_size / 100);

	D1(printk(KERN_DEBUG "JFFS2 trigger levels (size %d KiB, block size %d KiB, %d blocks)\n",
		  c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks));
	D1(printk(KERN_DEBUG "Blocks required to allow deletion:    %d (%d KiB)\n",
		  c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024));
	D1(printk(KERN_DEBUG "Blocks required to allow writes:      %d (%d KiB)\n",
		  c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024));
	D1(printk(KERN_DEBUG "Blocks required to quiesce GC thread: %d (%d KiB)\n",
		  c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024));
	D1(printk(KERN_DEBUG "Blocks required to allow GC merges:   %d (%d KiB)\n",
		  c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024));
	D1(printk(KERN_DEBUG "Blocks required to GC bad blocks:     %d (%d KiB)\n",
		  c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024));
	D1(printk(KERN_DEBUG "Amount of dirty space required to GC: %d bytes\n",
		  c->nospc_dirty_size));
} 

int jffs2_do_mount_fs(struct jffs2_sb_info *c)
{
	int i;

	c->free_size = c->flash_size;
	c->nr_blocks = c->flash_size / c->sector_size;
 	if (c->mtd->flags & MTD_NO_VIRTBLOCKS)
		c->blocks = vmalloc(sizeof(struct jffs2_eraseblock) * c->nr_blocks);
	else
		c->blocks = kmalloc(sizeof(struct jffs2_eraseblock) * c->nr_blocks, GFP_KERNEL);
	if (!c->blocks)
		return -ENOMEM;
	for (i=0; i<c->nr_blocks; i++) {
		INIT_LIST_HEAD(&c->blocks[i].list);
		c->blocks[i].offset = i * c->sector_size;
		c->blocks[i].free_size = c->sector_size;
		c->blocks[i].dirty_size = 0;
		c->blocks[i].wasted_size = 0;
		c->blocks[i].unchecked_size = 0;
		c->blocks[i].used_size = 0;
		c->blocks[i].first_node = NULL;
		c->blocks[i].last_node = NULL;
		c->blocks[i].bad_count = 0;
	}

	init_MUTEX(&c->alloc_sem);
	init_MUTEX(&c->erase_free_sem);
	init_waitqueue_head(&c->erase_wait);
	init_waitqueue_head(&c->inocache_wq);
	spin_lock_init(&c->erase_completion_lock);
	spin_lock_init(&c->inocache_lock);

	INIT_LIST_HEAD(&c->clean_list);
	INIT_LIST_HEAD(&c->very_dirty_list);
	INIT_LIST_HEAD(&c->dirty_list);
	INIT_LIST_HEAD(&c->erasable_list);
	INIT_LIST_HEAD(&c->erasing_list);
	INIT_LIST_HEAD(&c->erase_pending_list);
	INIT_LIST_HEAD(&c->erasable_pending_wbuf_list);
	INIT_LIST_HEAD(&c->erase_complete_list);
	INIT_LIST_HEAD(&c->free_list);
	INIT_LIST_HEAD(&c->bad_list);
	INIT_LIST_HEAD(&c->bad_used_list);
	c->highest_ino = 1;

	if (jffs2_build_filesystem(c)) {
		D1(printk(KERN_DEBUG "build_fs failed\n"));
		jffs2_free_ino_caches(c);
		jffs2_free_raw_node_refs(c);
		if (c->mtd->flags & MTD_NO_VIRTBLOCKS) {
			vfree(c->blocks);
		} else {
			kfree(c->blocks);
		}
		return -EIO;
	}

	jffs2_calc_trigger_levels(c);

	return 0;
}