ia64/linux-2.6.18-xen.hg

view fs/jffs2/build.c @ 524:7f8b544237bf

netfront: Allow netfront in domain 0.

This is useful if your physical network device is in a utility domain.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Apr 15 15:18:58 2008 +0100 (2008-04-15)
parents 831230e53067
children
line source
1 /*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright (C) 2001-2003 Red Hat, Inc.
5 *
6 * Created by David Woodhouse <dwmw2@infradead.org>
7 *
8 * For licensing information, see the file 'LICENCE' in this directory.
9 *
10 * $Id: build.c,v 1.85 2005/11/07 11:14:38 gleixner Exp $
11 *
12 */
14 #include <linux/kernel.h>
15 #include <linux/sched.h>
16 #include <linux/slab.h>
17 #include <linux/vmalloc.h>
18 #include <linux/mtd/mtd.h>
19 #include "nodelist.h"
21 static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *,
22 struct jffs2_inode_cache *, struct jffs2_full_dirent **);
24 static inline struct jffs2_inode_cache *
25 first_inode_chain(int *i, struct jffs2_sb_info *c)
26 {
27 for (; *i < INOCACHE_HASHSIZE; (*i)++) {
28 if (c->inocache_list[*i])
29 return c->inocache_list[*i];
30 }
31 return NULL;
32 }
34 static inline struct jffs2_inode_cache *
35 next_inode(int *i, struct jffs2_inode_cache *ic, struct jffs2_sb_info *c)
36 {
37 /* More in this chain? */
38 if (ic->next)
39 return ic->next;
40 (*i)++;
41 return first_inode_chain(i, c);
42 }
44 #define for_each_inode(i, c, ic) \
45 for (i = 0, ic = first_inode_chain(&i, (c)); \
46 ic; \
47 ic = next_inode(&i, ic, (c)))
50 static void jffs2_build_inode_pass1(struct jffs2_sb_info *c,
51 struct jffs2_inode_cache *ic)
52 {
53 struct jffs2_full_dirent *fd;
55 dbg_fsbuild("building directory inode #%u\n", ic->ino);
57 /* For each child, increase nlink */
58 for(fd = ic->scan_dents; fd; fd = fd->next) {
59 struct jffs2_inode_cache *child_ic;
60 if (!fd->ino)
61 continue;
63 /* we can get high latency here with huge directories */
65 child_ic = jffs2_get_ino_cache(c, fd->ino);
66 if (!child_ic) {
67 dbg_fsbuild("child \"%s\" (ino #%u) of dir ino #%u doesn't exist!\n",
68 fd->name, fd->ino, ic->ino);
69 jffs2_mark_node_obsolete(c, fd->raw);
70 continue;
71 }
73 if (child_ic->nlink++ && fd->type == DT_DIR) {
74 JFFS2_ERROR("child dir \"%s\" (ino #%u) of dir ino #%u appears to be a hard link\n",
75 fd->name, fd->ino, ic->ino);
76 /* TODO: What do we do about it? */
77 }
78 dbg_fsbuild("increased nlink for child \"%s\" (ino #%u)\n", fd->name, fd->ino);
79 /* Can't free scan_dents so far. We might need them in pass 2 */
80 }
81 }
83 /* Scan plan:
84 - Scan physical nodes. Build map of inodes/dirents. Allocate inocaches as we go
85 - Scan directory tree from top down, setting nlink in inocaches
86 - Scan inocaches for inodes with nlink==0
87 */
88 static int jffs2_build_filesystem(struct jffs2_sb_info *c)
89 {
90 int ret;
91 int i;
92 struct jffs2_inode_cache *ic;
93 struct jffs2_full_dirent *fd;
94 struct jffs2_full_dirent *dead_fds = NULL;
96 dbg_fsbuild("build FS data structures\n");
98 /* First, scan the medium and build all the inode caches with
99 lists of physical nodes */
101 c->flags |= JFFS2_SB_FLAG_SCANNING;
102 ret = jffs2_scan_medium(c);
103 c->flags &= ~JFFS2_SB_FLAG_SCANNING;
104 if (ret)
105 goto exit;
107 dbg_fsbuild("scanned flash completely\n");
108 jffs2_dbg_dump_block_lists_nolock(c);
110 dbg_fsbuild("pass 1 starting\n");
111 c->flags |= JFFS2_SB_FLAG_BUILDING;
112 /* Now scan the directory tree, increasing nlink according to every dirent found. */
113 for_each_inode(i, c, ic) {
114 if (ic->scan_dents) {
115 jffs2_build_inode_pass1(c, ic);
116 cond_resched();
117 }
118 }
120 dbg_fsbuild("pass 1 complete\n");
122 /* Next, scan for inodes with nlink == 0 and remove them. If
123 they were directories, then decrement the nlink of their
124 children too, and repeat the scan. As that's going to be
125 a fairly uncommon occurrence, it's not so evil to do it this
126 way. Recursion bad. */
127 dbg_fsbuild("pass 2 starting\n");
129 for_each_inode(i, c, ic) {
130 if (ic->nlink)
131 continue;
133 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
134 cond_resched();
135 }
137 dbg_fsbuild("pass 2a starting\n");
139 while (dead_fds) {
140 fd = dead_fds;
141 dead_fds = fd->next;
143 ic = jffs2_get_ino_cache(c, fd->ino);
145 if (ic)
146 jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
147 jffs2_free_full_dirent(fd);
148 }
150 dbg_fsbuild("pass 2a complete\n");
151 dbg_fsbuild("freeing temporary data structures\n");
153 /* Finally, we can scan again and free the dirent structs */
154 for_each_inode(i, c, ic) {
155 while(ic->scan_dents) {
156 fd = ic->scan_dents;
157 ic->scan_dents = fd->next;
158 jffs2_free_full_dirent(fd);
159 }
160 ic->scan_dents = NULL;
161 cond_resched();
162 }
163 jffs2_build_xattr_subsystem(c);
164 c->flags &= ~JFFS2_SB_FLAG_BUILDING;
166 dbg_fsbuild("FS build complete\n");
168 /* Rotate the lists by some number to ensure wear levelling */
169 jffs2_rotate_lists(c);
171 ret = 0;
173 exit:
174 if (ret) {
175 for_each_inode(i, c, ic) {
176 while(ic->scan_dents) {
177 fd = ic->scan_dents;
178 ic->scan_dents = fd->next;
179 jffs2_free_full_dirent(fd);
180 }
181 }
182 jffs2_clear_xattr_subsystem(c);
183 }
185 return ret;
186 }
188 static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c,
189 struct jffs2_inode_cache *ic,
190 struct jffs2_full_dirent **dead_fds)
191 {
192 struct jffs2_raw_node_ref *raw;
193 struct jffs2_full_dirent *fd;
195 dbg_fsbuild("removing ino #%u with nlink == zero.\n", ic->ino);
197 raw = ic->nodes;
198 while (raw != (void *)ic) {
199 struct jffs2_raw_node_ref *next = raw->next_in_ino;
200 dbg_fsbuild("obsoleting node at 0x%08x\n", ref_offset(raw));
201 jffs2_mark_node_obsolete(c, raw);
202 raw = next;
203 }
205 if (ic->scan_dents) {
206 int whinged = 0;
207 dbg_fsbuild("inode #%u was a directory which may have children...\n", ic->ino);
209 while(ic->scan_dents) {
210 struct jffs2_inode_cache *child_ic;
212 fd = ic->scan_dents;
213 ic->scan_dents = fd->next;
215 if (!fd->ino) {
216 /* It's a deletion dirent. Ignore it */
217 dbg_fsbuild("child \"%s\" is a deletion dirent, skipping...\n", fd->name);
218 jffs2_free_full_dirent(fd);
219 continue;
220 }
221 if (!whinged)
222 whinged = 1;
224 dbg_fsbuild("removing child \"%s\", ino #%u\n", fd->name, fd->ino);
226 child_ic = jffs2_get_ino_cache(c, fd->ino);
227 if (!child_ic) {
228 dbg_fsbuild("cannot remove child \"%s\", ino #%u, because it doesn't exist\n",
229 fd->name, fd->ino);
230 jffs2_free_full_dirent(fd);
231 continue;
232 }
234 /* Reduce nlink of the child. If it's now zero, stick it on the
235 dead_fds list to be cleaned up later. Else just free the fd */
237 child_ic->nlink--;
239 if (!child_ic->nlink) {
240 dbg_fsbuild("inode #%u (\"%s\") has now got zero nlink, adding to dead_fds list.\n",
241 fd->ino, fd->name);
242 fd->next = *dead_fds;
243 *dead_fds = fd;
244 } else {
245 dbg_fsbuild("inode #%u (\"%s\") has now got nlink %d. Ignoring.\n",
246 fd->ino, fd->name, child_ic->nlink);
247 jffs2_free_full_dirent(fd);
248 }
249 }
250 }
252 /*
253 We don't delete the inocache from the hash list and free it yet.
254 The erase code will do that, when all the nodes are completely gone.
255 */
256 }
258 static void jffs2_calc_trigger_levels(struct jffs2_sb_info *c)
259 {
260 uint32_t size;
262 /* Deletion should almost _always_ be allowed. We're fairly
263 buggered once we stop allowing people to delete stuff
264 because there's not enough free space... */
265 c->resv_blocks_deletion = 2;
267 /* Be conservative about how much space we need before we allow writes.
268 On top of that which is required for deletia, require an extra 2%
269 of the medium to be available, for overhead caused by nodes being
270 split across blocks, etc. */
272 size = c->flash_size / 50; /* 2% of flash size */
273 size += c->nr_blocks * 100; /* And 100 bytes per eraseblock */
274 size += c->sector_size - 1; /* ... and round up */
276 c->resv_blocks_write = c->resv_blocks_deletion + (size / c->sector_size);
278 /* When do we let the GC thread run in the background */
280 c->resv_blocks_gctrigger = c->resv_blocks_write + 1;
282 /* When do we allow garbage collection to merge nodes to make
283 long-term progress at the expense of short-term space exhaustion? */
284 c->resv_blocks_gcmerge = c->resv_blocks_deletion + 1;
286 /* When do we allow garbage collection to eat from bad blocks rather
287 than actually making progress? */
288 c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2;
290 /* If there's less than this amount of dirty space, don't bother
291 trying to GC to make more space. It'll be a fruitless task */
292 c->nospc_dirty_size = c->sector_size + (c->flash_size / 100);
294 dbg_fsbuild("JFFS2 trigger levels (size %d KiB, block size %d KiB, %d blocks)\n",
295 c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks);
296 dbg_fsbuild("Blocks required to allow deletion: %d (%d KiB)\n",
297 c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024);
298 dbg_fsbuild("Blocks required to allow writes: %d (%d KiB)\n",
299 c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024);
300 dbg_fsbuild("Blocks required to quiesce GC thread: %d (%d KiB)\n",
301 c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024);
302 dbg_fsbuild("Blocks required to allow GC merges: %d (%d KiB)\n",
303 c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024);
304 dbg_fsbuild("Blocks required to GC bad blocks: %d (%d KiB)\n",
305 c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024);
306 dbg_fsbuild("Amount of dirty space required to GC: %d bytes\n",
307 c->nospc_dirty_size);
308 }
310 int jffs2_do_mount_fs(struct jffs2_sb_info *c)
311 {
312 int ret;
313 int i;
314 int size;
316 c->free_size = c->flash_size;
317 c->nr_blocks = c->flash_size / c->sector_size;
318 size = sizeof(struct jffs2_eraseblock) * c->nr_blocks;
319 #ifndef __ECOS
320 if (jffs2_blocks_use_vmalloc(c))
321 c->blocks = vmalloc(size);
322 else
323 #endif
324 c->blocks = kmalloc(size, GFP_KERNEL);
325 if (!c->blocks)
326 return -ENOMEM;
328 memset(c->blocks, 0, size);
329 for (i=0; i<c->nr_blocks; i++) {
330 INIT_LIST_HEAD(&c->blocks[i].list);
331 c->blocks[i].offset = i * c->sector_size;
332 c->blocks[i].free_size = c->sector_size;
333 }
335 INIT_LIST_HEAD(&c->clean_list);
336 INIT_LIST_HEAD(&c->very_dirty_list);
337 INIT_LIST_HEAD(&c->dirty_list);
338 INIT_LIST_HEAD(&c->erasable_list);
339 INIT_LIST_HEAD(&c->erasing_list);
340 INIT_LIST_HEAD(&c->erase_pending_list);
341 INIT_LIST_HEAD(&c->erasable_pending_wbuf_list);
342 INIT_LIST_HEAD(&c->erase_complete_list);
343 INIT_LIST_HEAD(&c->free_list);
344 INIT_LIST_HEAD(&c->bad_list);
345 INIT_LIST_HEAD(&c->bad_used_list);
346 c->highest_ino = 1;
347 c->summary = NULL;
349 ret = jffs2_sum_init(c);
350 if (ret)
351 return ret;
353 if (jffs2_build_filesystem(c)) {
354 dbg_fsbuild("build_fs failed\n");
355 jffs2_free_ino_caches(c);
356 jffs2_free_raw_node_refs(c);
357 #ifndef __ECOS
358 if (jffs2_blocks_use_vmalloc(c))
359 vfree(c->blocks);
360 else
361 #endif
362 kfree(c->blocks);
364 return -EIO;
365 }
367 jffs2_calc_trigger_levels(c);
369 return 0;
370 }