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TOMOYO Linux Cross Reference
Linux/fs/jffs2/xattr.c

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  1 /*
  2  * JFFS2 -- Journalling Flash File System, Version 2.
  3  *
  4  * Copyright © 2006  NEC Corporation
  5  *
  6  * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
  7  *
  8  * For licensing information, see the file 'LICENCE' in this directory.
  9  *
 10  */
 11 
 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 13 
 14 #define JFFS2_XATTR_IS_CORRUPTED        1
 15 
 16 #include <linux/kernel.h>
 17 #include <linux/slab.h>
 18 #include <linux/fs.h>
 19 #include <linux/time.h>
 20 #include <linux/pagemap.h>
 21 #include <linux/highmem.h>
 22 #include <linux/crc32.h>
 23 #include <linux/jffs2.h>
 24 #include <linux/xattr.h>
 25 #include <linux/posix_acl_xattr.h>
 26 #include <linux/mtd/mtd.h>
 27 #include "nodelist.h"
 28 /* -------- xdatum related functions ----------------
 29  * xattr_datum_hashkey(xprefix, xname, xvalue, xsize)
 30  *   is used to calcurate xdatum hashkey. The reminder of hashkey into XATTRINDEX_HASHSIZE is
 31  *   the index of the xattr name/value pair cache (c->xattrindex).
 32  * is_xattr_datum_unchecked(c, xd)
 33  *   returns 1, if xdatum contains any unchecked raw nodes. if all raw nodes are not
 34  *   unchecked, it returns 0.
 35  * unload_xattr_datum(c, xd)
 36  *   is used to release xattr name/value pair and detach from c->xattrindex.
 37  * reclaim_xattr_datum(c)
 38  *   is used to reclaim xattr name/value pairs on the xattr name/value pair cache when
 39  *   memory usage by cache is over c->xdatum_mem_threshold. Currently, this threshold
 40  *   is hard coded as 32KiB.
 41  * do_verify_xattr_datum(c, xd)
 42  *   is used to load the xdatum informations without name/value pair from the medium.
 43  *   It's necessary once, because those informations are not collected during mounting
 44  *   process when EBS is enabled.
 45  *   0 will be returned, if success. An negative return value means recoverable error, and
 46  *   positive return value means unrecoverable error. Thus, caller must remove this xdatum
 47  *   and xref when it returned positive value.
 48  * do_load_xattr_datum(c, xd)
 49  *   is used to load name/value pair from the medium.
 50  *   The meanings of return value is same as do_verify_xattr_datum().
 51  * load_xattr_datum(c, xd)
 52  *   is used to be as a wrapper of do_verify_xattr_datum() and do_load_xattr_datum().
 53  *   If xd need to call do_verify_xattr_datum() at first, it's called before calling
 54  *   do_load_xattr_datum(). The meanings of return value is same as do_verify_xattr_datum().
 55  * save_xattr_datum(c, xd)
 56  *   is used to write xdatum to medium. xd->version will be incremented.
 57  * create_xattr_datum(c, xprefix, xname, xvalue, xsize)
 58  *   is used to create new xdatum and write to medium.
 59  * unrefer_xattr_datum(c, xd)
 60  *   is used to delete a xdatum. When nobody refers this xdatum, JFFS2_XFLAGS_DEAD
 61  *   is set on xd->flags and chained xattr_dead_list or release it immediately.
 62  *   In the first case, the garbage collector release it later.
 63  * -------------------------------------------------- */
 64 static uint32_t xattr_datum_hashkey(int xprefix, const char *xname, const char *xvalue, int xsize)
 65 {
 66         int name_len = strlen(xname);
 67 
 68         return crc32(xprefix, xname, name_len) ^ crc32(xprefix, xvalue, xsize);
 69 }
 70 
 71 static int is_xattr_datum_unchecked(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
 72 {
 73         struct jffs2_raw_node_ref *raw;
 74         int rc = 0;
 75 
 76         spin_lock(&c->erase_completion_lock);
 77         for (raw=xd->node; raw != (void *)xd; raw=raw->next_in_ino) {
 78                 if (ref_flags(raw) == REF_UNCHECKED) {
 79                         rc = 1;
 80                         break;
 81                 }
 82         }
 83         spin_unlock(&c->erase_completion_lock);
 84         return rc;
 85 }
 86 
 87 static void unload_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
 88 {
 89         /* must be called under down_write(xattr_sem) */
 90         D1(dbg_xattr("%s: xid=%u, version=%u\n", __func__, xd->xid, xd->version));
 91         if (xd->xname) {
 92                 c->xdatum_mem_usage -= (xd->name_len + 1 + xd->value_len);
 93                 kfree(xd->xname);
 94         }
 95 
 96         list_del_init(&xd->xindex);
 97         xd->hashkey = 0;
 98         xd->xname = NULL;
 99         xd->xvalue = NULL;
100 }
101 
102 static void reclaim_xattr_datum(struct jffs2_sb_info *c)
103 {
104         /* must be called under down_write(xattr_sem) */
105         struct jffs2_xattr_datum *xd, *_xd;
106         uint32_t target, before;
107         static int index = 0;
108         int count;
109 
110         if (c->xdatum_mem_threshold > c->xdatum_mem_usage)
111                 return;
112 
113         before = c->xdatum_mem_usage;
114         target = c->xdatum_mem_usage * 4 / 5; /* 20% reduction */
115         for (count = 0; count < XATTRINDEX_HASHSIZE; count++) {
116                 list_for_each_entry_safe(xd, _xd, &c->xattrindex[index], xindex) {
117                         if (xd->flags & JFFS2_XFLAGS_HOT) {
118                                 xd->flags &= ~JFFS2_XFLAGS_HOT;
119                         } else if (!(xd->flags & JFFS2_XFLAGS_BIND)) {
120                                 unload_xattr_datum(c, xd);
121                         }
122                         if (c->xdatum_mem_usage <= target)
123                                 goto out;
124                 }
125                 index = (index+1) % XATTRINDEX_HASHSIZE;
126         }
127  out:
128         JFFS2_NOTICE("xdatum_mem_usage from %u byte to %u byte (%u byte reclaimed)\n",
129                      before, c->xdatum_mem_usage, before - c->xdatum_mem_usage);
130 }
131 
132 static int do_verify_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
133 {
134         /* must be called under down_write(xattr_sem) */
135         struct jffs2_eraseblock *jeb;
136         struct jffs2_raw_node_ref *raw;
137         struct jffs2_raw_xattr rx;
138         size_t readlen;
139         uint32_t crc, offset, totlen;
140         int rc;
141 
142         spin_lock(&c->erase_completion_lock);
143         offset = ref_offset(xd->node);
144         if (ref_flags(xd->node) == REF_PRISTINE)
145                 goto complete;
146         spin_unlock(&c->erase_completion_lock);
147 
148         rc = jffs2_flash_read(c, offset, sizeof(rx), &readlen, (char *)&rx);
149         if (rc || readlen != sizeof(rx)) {
150                 JFFS2_WARNING("jffs2_flash_read()=%d, req=%zu, read=%zu at %#08x\n",
151                               rc, sizeof(rx), readlen, offset);
152                 return rc ? rc : -EIO;
153         }
154         crc = crc32(0, &rx, sizeof(rx) - 4);
155         if (crc != je32_to_cpu(rx.node_crc)) {
156                 JFFS2_ERROR("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
157                             offset, je32_to_cpu(rx.hdr_crc), crc);
158                 xd->flags |= JFFS2_XFLAGS_INVALID;
159                 return JFFS2_XATTR_IS_CORRUPTED;
160         }
161         totlen = PAD(sizeof(rx) + rx.name_len + 1 + je16_to_cpu(rx.value_len));
162         if (je16_to_cpu(rx.magic) != JFFS2_MAGIC_BITMASK
163             || je16_to_cpu(rx.nodetype) != JFFS2_NODETYPE_XATTR
164             || je32_to_cpu(rx.totlen) != totlen
165             || je32_to_cpu(rx.xid) != xd->xid
166             || je32_to_cpu(rx.version) != xd->version) {
167                 JFFS2_ERROR("inconsistent xdatum at %#08x, magic=%#04x/%#04x, "
168                             "nodetype=%#04x/%#04x, totlen=%u/%u, xid=%u/%u, version=%u/%u\n",
169                             offset, je16_to_cpu(rx.magic), JFFS2_MAGIC_BITMASK,
170                             je16_to_cpu(rx.nodetype), JFFS2_NODETYPE_XATTR,
171                             je32_to_cpu(rx.totlen), totlen,
172                             je32_to_cpu(rx.xid), xd->xid,
173                             je32_to_cpu(rx.version), xd->version);
174                 xd->flags |= JFFS2_XFLAGS_INVALID;
175                 return JFFS2_XATTR_IS_CORRUPTED;
176         }
177         xd->xprefix = rx.xprefix;
178         xd->name_len = rx.name_len;
179         xd->value_len = je16_to_cpu(rx.value_len);
180         xd->data_crc = je32_to_cpu(rx.data_crc);
181 
182         spin_lock(&c->erase_completion_lock);
183  complete:
184         for (raw=xd->node; raw != (void *)xd; raw=raw->next_in_ino) {
185                 jeb = &c->blocks[ref_offset(raw) / c->sector_size];
186                 totlen = PAD(ref_totlen(c, jeb, raw));
187                 if (ref_flags(raw) == REF_UNCHECKED) {
188                         c->unchecked_size -= totlen; c->used_size += totlen;
189                         jeb->unchecked_size -= totlen; jeb->used_size += totlen;
190                 }
191                 raw->flash_offset = ref_offset(raw) | ((xd->node==raw) ? REF_PRISTINE : REF_NORMAL);
192         }
193         spin_unlock(&c->erase_completion_lock);
194 
195         /* unchecked xdatum is chained with c->xattr_unchecked */
196         list_del_init(&xd->xindex);
197 
198         dbg_xattr("success on verifying xdatum (xid=%u, version=%u)\n",
199                   xd->xid, xd->version);
200 
201         return 0;
202 }
203 
204 static int do_load_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
205 {
206         /* must be called under down_write(xattr_sem) */
207         char *data;
208         size_t readlen;
209         uint32_t crc, length;
210         int i, ret, retry = 0;
211 
212         BUG_ON(ref_flags(xd->node) != REF_PRISTINE);
213         BUG_ON(!list_empty(&xd->xindex));
214  retry:
215         length = xd->name_len + 1 + xd->value_len;
216         data = kmalloc(length, GFP_KERNEL);
217         if (!data)
218                 return -ENOMEM;
219 
220         ret = jffs2_flash_read(c, ref_offset(xd->node)+sizeof(struct jffs2_raw_xattr),
221                                length, &readlen, data);
222 
223         if (ret || length!=readlen) {
224                 JFFS2_WARNING("jffs2_flash_read() returned %d, request=%d, readlen=%zu, at %#08x\n",
225                               ret, length, readlen, ref_offset(xd->node));
226                 kfree(data);
227                 return ret ? ret : -EIO;
228         }
229 
230         data[xd->name_len] = '\0';
231         crc = crc32(0, data, length);
232         if (crc != xd->data_crc) {
233                 JFFS2_WARNING("node CRC failed (JFFS2_NODETYPE_XATTR)"
234                               " at %#08x, read: 0x%08x calculated: 0x%08x\n",
235                               ref_offset(xd->node), xd->data_crc, crc);
236                 kfree(data);
237                 xd->flags |= JFFS2_XFLAGS_INVALID;
238                 return JFFS2_XATTR_IS_CORRUPTED;
239         }
240 
241         xd->flags |= JFFS2_XFLAGS_HOT;
242         xd->xname = data;
243         xd->xvalue = data + xd->name_len+1;
244 
245         c->xdatum_mem_usage += length;
246 
247         xd->hashkey = xattr_datum_hashkey(xd->xprefix, xd->xname, xd->xvalue, xd->value_len);
248         i = xd->hashkey % XATTRINDEX_HASHSIZE;
249         list_add(&xd->xindex, &c->xattrindex[i]);
250         if (!retry) {
251                 retry = 1;
252                 reclaim_xattr_datum(c);
253                 if (!xd->xname)
254                         goto retry;
255         }
256 
257         dbg_xattr("success on loading xdatum (xid=%u, xprefix=%u, xname='%s')\n",
258                   xd->xid, xd->xprefix, xd->xname);
259 
260         return 0;
261 }
262 
263 static int load_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
264 {
265         /* must be called under down_write(xattr_sem);
266          * rc < 0 : recoverable error, try again
267          * rc = 0 : success
268          * rc > 0 : Unrecoverable error, this node should be deleted.
269          */
270         int rc = 0;
271 
272         BUG_ON(xd->flags & JFFS2_XFLAGS_DEAD);
273         if (xd->xname)
274                 return 0;
275         if (xd->flags & JFFS2_XFLAGS_INVALID)
276                 return JFFS2_XATTR_IS_CORRUPTED;
277         if (unlikely(is_xattr_datum_unchecked(c, xd)))
278                 rc = do_verify_xattr_datum(c, xd);
279         if (!rc)
280                 rc = do_load_xattr_datum(c, xd);
281         return rc;
282 }
283 
284 static int save_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
285 {
286         /* must be called under down_write(xattr_sem) */
287         struct jffs2_raw_xattr rx;
288         struct kvec vecs[2];
289         size_t length;
290         int rc, totlen;
291         uint32_t phys_ofs = write_ofs(c);
292 
293         BUG_ON(!xd->xname);
294         BUG_ON(xd->flags & (JFFS2_XFLAGS_DEAD|JFFS2_XFLAGS_INVALID));
295 
296         vecs[0].iov_base = &rx;
297         vecs[0].iov_len = sizeof(rx);
298         vecs[1].iov_base = xd->xname;
299         vecs[1].iov_len = xd->name_len + 1 + xd->value_len;
300         totlen = vecs[0].iov_len + vecs[1].iov_len;
301 
302         /* Setup raw-xattr */
303         memset(&rx, 0, sizeof(rx));
304         rx.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
305         rx.nodetype = cpu_to_je16(JFFS2_NODETYPE_XATTR);
306         rx.totlen = cpu_to_je32(PAD(totlen));
307         rx.hdr_crc = cpu_to_je32(crc32(0, &rx, sizeof(struct jffs2_unknown_node) - 4));
308 
309         rx.xid = cpu_to_je32(xd->xid);
310         rx.version = cpu_to_je32(++xd->version);
311         rx.xprefix = xd->xprefix;
312         rx.name_len = xd->name_len;
313         rx.value_len = cpu_to_je16(xd->value_len);
314         rx.data_crc = cpu_to_je32(crc32(0, vecs[1].iov_base, vecs[1].iov_len));
315         rx.node_crc = cpu_to_je32(crc32(0, &rx, sizeof(struct jffs2_raw_xattr) - 4));
316 
317         rc = jffs2_flash_writev(c, vecs, 2, phys_ofs, &length, 0);
318         if (rc || totlen != length) {
319                 JFFS2_WARNING("jffs2_flash_writev()=%d, req=%u, wrote=%zu, at %#08x\n",
320                               rc, totlen, length, phys_ofs);
321                 rc = rc ? rc : -EIO;
322                 if (length)
323                         jffs2_add_physical_node_ref(c, phys_ofs | REF_OBSOLETE, PAD(totlen), NULL);
324 
325                 return rc;
326         }
327         /* success */
328         jffs2_add_physical_node_ref(c, phys_ofs | REF_PRISTINE, PAD(totlen), (void *)xd);
329 
330         dbg_xattr("success on saving xdatum (xid=%u, version=%u, xprefix=%u, xname='%s')\n",
331                   xd->xid, xd->version, xd->xprefix, xd->xname);
332 
333         return 0;
334 }
335 
336 static struct jffs2_xattr_datum *create_xattr_datum(struct jffs2_sb_info *c,
337                                                     int xprefix, const char *xname,
338                                                     const char *xvalue, int xsize)
339 {
340         /* must be called under down_write(xattr_sem) */
341         struct jffs2_xattr_datum *xd;
342         uint32_t hashkey, name_len;
343         char *data;
344         int i, rc;
345 
346         /* Search xattr_datum has same xname/xvalue by index */
347         hashkey = xattr_datum_hashkey(xprefix, xname, xvalue, xsize);
348         i = hashkey % XATTRINDEX_HASHSIZE;
349         list_for_each_entry(xd, &c->xattrindex[i], xindex) {
350                 if (xd->hashkey==hashkey
351                     && xd->xprefix==xprefix
352                     && xd->value_len==xsize
353                     && !strcmp(xd->xname, xname)
354                     && !memcmp(xd->xvalue, xvalue, xsize)) {
355                         atomic_inc(&xd->refcnt);
356                         return xd;
357                 }
358         }
359 
360         /* Not found, Create NEW XATTR-Cache */
361         name_len = strlen(xname);
362 
363         xd = jffs2_alloc_xattr_datum();
364         if (!xd)
365                 return ERR_PTR(-ENOMEM);
366 
367         data = kmalloc(name_len + 1 + xsize, GFP_KERNEL);
368         if (!data) {
369                 jffs2_free_xattr_datum(xd);
370                 return ERR_PTR(-ENOMEM);
371         }
372         strcpy(data, xname);
373         memcpy(data + name_len + 1, xvalue, xsize);
374 
375         atomic_set(&xd->refcnt, 1);
376         xd->xid = ++c->highest_xid;
377         xd->flags |= JFFS2_XFLAGS_HOT;
378         xd->xprefix = xprefix;
379 
380         xd->hashkey = hashkey;
381         xd->xname = data;
382         xd->xvalue = data + name_len + 1;
383         xd->name_len = name_len;
384         xd->value_len = xsize;
385         xd->data_crc = crc32(0, data, xd->name_len + 1 + xd->value_len);
386 
387         rc = save_xattr_datum(c, xd);
388         if (rc) {
389                 kfree(xd->xname);
390                 jffs2_free_xattr_datum(xd);
391                 return ERR_PTR(rc);
392         }
393 
394         /* Insert Hash Index */
395         i = hashkey % XATTRINDEX_HASHSIZE;
396         list_add(&xd->xindex, &c->xattrindex[i]);
397 
398         c->xdatum_mem_usage += (xd->name_len + 1 + xd->value_len);
399         reclaim_xattr_datum(c);
400 
401         return xd;
402 }
403 
404 static void unrefer_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
405 {
406         /* must be called under down_write(xattr_sem) */
407         if (atomic_dec_and_lock(&xd->refcnt, &c->erase_completion_lock)) {
408                 unload_xattr_datum(c, xd);
409                 xd->flags |= JFFS2_XFLAGS_DEAD;
410                 if (xd->node == (void *)xd) {
411                         BUG_ON(!(xd->flags & JFFS2_XFLAGS_INVALID));
412                         jffs2_free_xattr_datum(xd);
413                 } else {
414                         list_add(&xd->xindex, &c->xattr_dead_list);
415                 }
416                 spin_unlock(&c->erase_completion_lock);
417 
418                 dbg_xattr("xdatum(xid=%u, version=%u) was removed.\n",
419                           xd->xid, xd->version);
420         }
421 }
422 
423 /* -------- xref related functions ------------------
424  * verify_xattr_ref(c, ref)
425  *   is used to load xref information from medium. Because summary data does not
426  *   contain xid/ino, it's necessary to verify once while mounting process.
427  * save_xattr_ref(c, ref)
428  *   is used to write xref to medium. If delete marker is marked, it write
429  *   a delete marker of xref into medium.
430  * create_xattr_ref(c, ic, xd)
431  *   is used to create a new xref and write to medium.
432  * delete_xattr_ref(c, ref)
433  *   is used to delete jffs2_xattr_ref. It marks xref XREF_DELETE_MARKER,
434  *   and allows GC to reclaim those physical nodes.
435  * jffs2_xattr_delete_inode(c, ic)
436  *   is called to remove xrefs related to obsolete inode when inode is unlinked.
437  * jffs2_xattr_free_inode(c, ic)
438  *   is called to release xattr related objects when unmounting. 
439  * check_xattr_ref_inode(c, ic)
440  *   is used to confirm inode does not have duplicate xattr name/value pair.
441  * jffs2_xattr_do_crccheck_inode(c, ic)
442  *   is used to force xattr data integrity check during the initial gc scan.
443  * -------------------------------------------------- */
444 static int verify_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
445 {
446         struct jffs2_eraseblock *jeb;
447         struct jffs2_raw_node_ref *raw;
448         struct jffs2_raw_xref rr;
449         size_t readlen;
450         uint32_t crc, offset, totlen;
451         int rc;
452 
453         spin_lock(&c->erase_completion_lock);
454         if (ref_flags(ref->node) != REF_UNCHECKED)
455                 goto complete;
456         offset = ref_offset(ref->node);
457         spin_unlock(&c->erase_completion_lock);
458 
459         rc = jffs2_flash_read(c, offset, sizeof(rr), &readlen, (char *)&rr);
460         if (rc || sizeof(rr) != readlen) {
461                 JFFS2_WARNING("jffs2_flash_read()=%d, req=%zu, read=%zu, at %#08x\n",
462                               rc, sizeof(rr), readlen, offset);
463                 return rc ? rc : -EIO;
464         }
465         /* obsolete node */
466         crc = crc32(0, &rr, sizeof(rr) - 4);
467         if (crc != je32_to_cpu(rr.node_crc)) {
468                 JFFS2_ERROR("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
469                             offset, je32_to_cpu(rr.node_crc), crc);
470                 return JFFS2_XATTR_IS_CORRUPTED;
471         }
472         if (je16_to_cpu(rr.magic) != JFFS2_MAGIC_BITMASK
473             || je16_to_cpu(rr.nodetype) != JFFS2_NODETYPE_XREF
474             || je32_to_cpu(rr.totlen) != PAD(sizeof(rr))) {
475                 JFFS2_ERROR("inconsistent xref at %#08x, magic=%#04x/%#04x, "
476                             "nodetype=%#04x/%#04x, totlen=%u/%zu\n",
477                             offset, je16_to_cpu(rr.magic), JFFS2_MAGIC_BITMASK,
478                             je16_to_cpu(rr.nodetype), JFFS2_NODETYPE_XREF,
479                             je32_to_cpu(rr.totlen), PAD(sizeof(rr)));
480                 return JFFS2_XATTR_IS_CORRUPTED;
481         }
482         ref->ino = je32_to_cpu(rr.ino);
483         ref->xid = je32_to_cpu(rr.xid);
484         ref->xseqno = je32_to_cpu(rr.xseqno);
485         if (ref->xseqno > c->highest_xseqno)
486                 c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
487 
488         spin_lock(&c->erase_completion_lock);
489  complete:
490         for (raw=ref->node; raw != (void *)ref; raw=raw->next_in_ino) {
491                 jeb = &c->blocks[ref_offset(raw) / c->sector_size];
492                 totlen = PAD(ref_totlen(c, jeb, raw));
493                 if (ref_flags(raw) == REF_UNCHECKED) {
494                         c->unchecked_size -= totlen; c->used_size += totlen;
495                         jeb->unchecked_size -= totlen; jeb->used_size += totlen;
496                 }
497                 raw->flash_offset = ref_offset(raw) | ((ref->node==raw) ? REF_PRISTINE : REF_NORMAL);
498         }
499         spin_unlock(&c->erase_completion_lock);
500 
501         dbg_xattr("success on verifying xref (ino=%u, xid=%u) at %#08x\n",
502                   ref->ino, ref->xid, ref_offset(ref->node));
503         return 0;
504 }
505 
506 static int save_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
507 {
508         /* must be called under down_write(xattr_sem) */
509         struct jffs2_raw_xref rr;
510         size_t length;
511         uint32_t xseqno, phys_ofs = write_ofs(c);
512         int ret;
513 
514         rr.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
515         rr.nodetype = cpu_to_je16(JFFS2_NODETYPE_XREF);
516         rr.totlen = cpu_to_je32(PAD(sizeof(rr)));
517         rr.hdr_crc = cpu_to_je32(crc32(0, &rr, sizeof(struct jffs2_unknown_node) - 4));
518 
519         xseqno = (c->highest_xseqno += 2);
520         if (is_xattr_ref_dead(ref)) {
521                 xseqno |= XREF_DELETE_MARKER;
522                 rr.ino = cpu_to_je32(ref->ino);
523                 rr.xid = cpu_to_je32(ref->xid);
524         } else {
525                 rr.ino = cpu_to_je32(ref->ic->ino);
526                 rr.xid = cpu_to_je32(ref->xd->xid);
527         }
528         rr.xseqno = cpu_to_je32(xseqno);
529         rr.node_crc = cpu_to_je32(crc32(0, &rr, sizeof(rr) - 4));
530 
531         ret = jffs2_flash_write(c, phys_ofs, sizeof(rr), &length, (char *)&rr);
532         if (ret || sizeof(rr) != length) {
533                 JFFS2_WARNING("jffs2_flash_write() returned %d, request=%zu, retlen=%zu, at %#08x\n",
534                               ret, sizeof(rr), length, phys_ofs);
535                 ret = ret ? ret : -EIO;
536                 if (length)
537                         jffs2_add_physical_node_ref(c, phys_ofs | REF_OBSOLETE, PAD(sizeof(rr)), NULL);
538 
539                 return ret;
540         }
541         /* success */
542         ref->xseqno = xseqno;
543         jffs2_add_physical_node_ref(c, phys_ofs | REF_PRISTINE, PAD(sizeof(rr)), (void *)ref);
544 
545         dbg_xattr("success on saving xref (ino=%u, xid=%u)\n", ref->ic->ino, ref->xd->xid);
546 
547         return 0;
548 }
549 
550 static struct jffs2_xattr_ref *create_xattr_ref(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic,
551                                                 struct jffs2_xattr_datum *xd)
552 {
553         /* must be called under down_write(xattr_sem) */
554         struct jffs2_xattr_ref *ref;
555         int ret;
556 
557         ref = jffs2_alloc_xattr_ref();
558         if (!ref)
559                 return ERR_PTR(-ENOMEM);
560         ref->ic = ic;
561         ref->xd = xd;
562 
563         ret = save_xattr_ref(c, ref);
564         if (ret) {
565                 jffs2_free_xattr_ref(ref);
566                 return ERR_PTR(ret);
567         }
568 
569         /* Chain to inode */
570         ref->next = ic->xref;
571         ic->xref = ref;
572 
573         return ref; /* success */
574 }
575 
576 static void delete_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
577 {
578         /* must be called under down_write(xattr_sem) */
579         struct jffs2_xattr_datum *xd;
580 
581         xd = ref->xd;
582         ref->xseqno |= XREF_DELETE_MARKER;
583         ref->ino = ref->ic->ino;
584         ref->xid = ref->xd->xid;
585         spin_lock(&c->erase_completion_lock);
586         ref->next = c->xref_dead_list;
587         c->xref_dead_list = ref;
588         spin_unlock(&c->erase_completion_lock);
589 
590         dbg_xattr("xref(ino=%u, xid=%u, xseqno=%u) was removed.\n",
591                   ref->ino, ref->xid, ref->xseqno);
592 
593         unrefer_xattr_datum(c, xd);
594 }
595 
596 void jffs2_xattr_delete_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
597 {
598         /* It's called from jffs2_evict_inode() on inode removing.
599            When an inode with XATTR is removed, those XATTRs must be removed. */
600         struct jffs2_xattr_ref *ref, *_ref;
601 
602         if (!ic || ic->pino_nlink > 0)
603                 return;
604 
605         down_write(&c->xattr_sem);
606         for (ref = ic->xref; ref; ref = _ref) {
607                 _ref = ref->next;
608                 delete_xattr_ref(c, ref);
609         }
610         ic->xref = NULL;
611         up_write(&c->xattr_sem);
612 }
613 
614 void jffs2_xattr_free_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
615 {
616         /* It's called from jffs2_free_ino_caches() until unmounting FS. */
617         struct jffs2_xattr_datum *xd;
618         struct jffs2_xattr_ref *ref, *_ref;
619 
620         down_write(&c->xattr_sem);
621         for (ref = ic->xref; ref; ref = _ref) {
622                 _ref = ref->next;
623                 xd = ref->xd;
624                 if (atomic_dec_and_test(&xd->refcnt)) {
625                         unload_xattr_datum(c, xd);
626                         jffs2_free_xattr_datum(xd);
627                 }
628                 jffs2_free_xattr_ref(ref);
629         }
630         ic->xref = NULL;
631         up_write(&c->xattr_sem);
632 }
633 
634 static int check_xattr_ref_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
635 {
636         /* success of check_xattr_ref_inode() means that inode (ic) dose not have
637          * duplicate name/value pairs. If duplicate name/value pair would be found,
638          * one will be removed.
639          */
640         struct jffs2_xattr_ref *ref, *cmp, **pref, **pcmp;
641         int rc = 0;
642 
643         if (likely(ic->flags & INO_FLAGS_XATTR_CHECKED))
644                 return 0;
645         down_write(&c->xattr_sem);
646  retry:
647         rc = 0;
648         for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
649                 if (!ref->xd->xname) {
650                         rc = load_xattr_datum(c, ref->xd);
651                         if (unlikely(rc > 0)) {
652                                 *pref = ref->next;
653                                 delete_xattr_ref(c, ref);
654                                 goto retry;
655                         } else if (unlikely(rc < 0))
656                                 goto out;
657                 }
658                 for (cmp=ref->next, pcmp=&ref->next; cmp; pcmp=&cmp->next, cmp=cmp->next) {
659                         if (!cmp->xd->xname) {
660                                 ref->xd->flags |= JFFS2_XFLAGS_BIND;
661                                 rc = load_xattr_datum(c, cmp->xd);
662                                 ref->xd->flags &= ~JFFS2_XFLAGS_BIND;
663                                 if (unlikely(rc > 0)) {
664                                         *pcmp = cmp->next;
665                                         delete_xattr_ref(c, cmp);
666                                         goto retry;
667                                 } else if (unlikely(rc < 0))
668                                         goto out;
669                         }
670                         if (ref->xd->xprefix == cmp->xd->xprefix
671                             && !strcmp(ref->xd->xname, cmp->xd->xname)) {
672                                 if (ref->xseqno > cmp->xseqno) {
673                                         *pcmp = cmp->next;
674                                         delete_xattr_ref(c, cmp);
675                                 } else {
676                                         *pref = ref->next;
677                                         delete_xattr_ref(c, ref);
678                                 }
679                                 goto retry;
680                         }
681                 }
682         }
683         ic->flags |= INO_FLAGS_XATTR_CHECKED;
684  out:
685         up_write(&c->xattr_sem);
686 
687         return rc;
688 }
689 
690 void jffs2_xattr_do_crccheck_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
691 {
692         check_xattr_ref_inode(c, ic);
693 }
694 
695 /* -------- xattr subsystem functions ---------------
696  * jffs2_init_xattr_subsystem(c)
697  *   is used to initialize semaphore and list_head, and some variables.
698  * jffs2_find_xattr_datum(c, xid)
699  *   is used to lookup xdatum while scanning process.
700  * jffs2_clear_xattr_subsystem(c)
701  *   is used to release any xattr related objects.
702  * jffs2_build_xattr_subsystem(c)
703  *   is used to associate xdatum and xref while super block building process.
704  * jffs2_setup_xattr_datum(c, xid, version)
705  *   is used to insert xdatum while scanning process.
706  * -------------------------------------------------- */
707 void jffs2_init_xattr_subsystem(struct jffs2_sb_info *c)
708 {
709         int i;
710 
711         for (i=0; i < XATTRINDEX_HASHSIZE; i++)
712                 INIT_LIST_HEAD(&c->xattrindex[i]);
713         INIT_LIST_HEAD(&c->xattr_unchecked);
714         INIT_LIST_HEAD(&c->xattr_dead_list);
715         c->xref_dead_list = NULL;
716         c->xref_temp = NULL;
717 
718         init_rwsem(&c->xattr_sem);
719         c->highest_xid = 0;
720         c->highest_xseqno = 0;
721         c->xdatum_mem_usage = 0;
722         c->xdatum_mem_threshold = 32 * 1024;    /* Default 32KB */
723 }
724 
725 static struct jffs2_xattr_datum *jffs2_find_xattr_datum(struct jffs2_sb_info *c, uint32_t xid)
726 {
727         struct jffs2_xattr_datum *xd;
728         int i = xid % XATTRINDEX_HASHSIZE;
729 
730         /* It's only used in scanning/building process. */
731         BUG_ON(!(c->flags & (JFFS2_SB_FLAG_SCANNING|JFFS2_SB_FLAG_BUILDING)));
732 
733         list_for_each_entry(xd, &c->xattrindex[i], xindex) {
734                 if (xd->xid==xid)
735                         return xd;
736         }
737         return NULL;
738 }
739 
740 void jffs2_clear_xattr_subsystem(struct jffs2_sb_info *c)
741 {
742         struct jffs2_xattr_datum *xd, *_xd;
743         struct jffs2_xattr_ref *ref, *_ref;
744         int i;
745 
746         for (ref=c->xref_temp; ref; ref = _ref) {
747                 _ref = ref->next;
748                 jffs2_free_xattr_ref(ref);
749         }
750 
751         for (ref=c->xref_dead_list; ref; ref = _ref) {
752                 _ref = ref->next;
753                 jffs2_free_xattr_ref(ref);
754         }
755 
756         for (i=0; i < XATTRINDEX_HASHSIZE; i++) {
757                 list_for_each_entry_safe(xd, _xd, &c->xattrindex[i], xindex) {
758                         list_del(&xd->xindex);
759                         kfree(xd->xname);
760                         jffs2_free_xattr_datum(xd);
761                 }
762         }
763 
764         list_for_each_entry_safe(xd, _xd, &c->xattr_dead_list, xindex) {
765                 list_del(&xd->xindex);
766                 jffs2_free_xattr_datum(xd);
767         }
768         list_for_each_entry_safe(xd, _xd, &c->xattr_unchecked, xindex) {
769                 list_del(&xd->xindex);
770                 jffs2_free_xattr_datum(xd);
771         }
772 }
773 
774 #define XREF_TMPHASH_SIZE       (128)
775 void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
776 {
777         struct jffs2_xattr_ref *ref, *_ref;
778         struct jffs2_xattr_ref *xref_tmphash[XREF_TMPHASH_SIZE];
779         struct jffs2_xattr_datum *xd, *_xd;
780         struct jffs2_inode_cache *ic;
781         struct jffs2_raw_node_ref *raw;
782         int i, xdatum_count = 0, xdatum_unchecked_count = 0, xref_count = 0;
783         int xdatum_orphan_count = 0, xref_orphan_count = 0, xref_dead_count = 0;
784 
785         BUG_ON(!(c->flags & JFFS2_SB_FLAG_BUILDING));
786 
787         /* Phase.1 : Merge same xref */
788         for (i=0; i < XREF_TMPHASH_SIZE; i++)
789                 xref_tmphash[i] = NULL;
790         for (ref=c->xref_temp; ref; ref=_ref) {
791                 struct jffs2_xattr_ref *tmp;
792 
793                 _ref = ref->next;
794                 if (ref_flags(ref->node) != REF_PRISTINE) {
795                         if (verify_xattr_ref(c, ref)) {
796                                 BUG_ON(ref->node->next_in_ino != (void *)ref);
797                                 ref->node->next_in_ino = NULL;
798                                 jffs2_mark_node_obsolete(c, ref->node);
799                                 jffs2_free_xattr_ref(ref);
800                                 continue;
801                         }
802                 }
803 
804                 i = (ref->ino ^ ref->xid) % XREF_TMPHASH_SIZE;
805                 for (tmp=xref_tmphash[i]; tmp; tmp=tmp->next) {
806                         if (tmp->ino == ref->ino && tmp->xid == ref->xid)
807                                 break;
808                 }
809                 if (tmp) {
810                         raw = ref->node;
811                         if (ref->xseqno > tmp->xseqno) {
812                                 tmp->xseqno = ref->xseqno;
813                                 raw->next_in_ino = tmp->node;
814                                 tmp->node = raw;
815                         } else {
816                                 raw->next_in_ino = tmp->node->next_in_ino;
817                                 tmp->node->next_in_ino = raw;
818                         }
819                         jffs2_free_xattr_ref(ref);
820                         continue;
821                 } else {
822                         ref->next = xref_tmphash[i];
823                         xref_tmphash[i] = ref;
824                 }
825         }
826         c->xref_temp = NULL;
827 
828         /* Phase.2 : Bind xref with inode_cache and xattr_datum */
829         for (i=0; i < XREF_TMPHASH_SIZE; i++) {
830                 for (ref=xref_tmphash[i]; ref; ref=_ref) {
831                         xref_count++;
832                         _ref = ref->next;
833                         if (is_xattr_ref_dead(ref)) {
834                                 ref->next = c->xref_dead_list;
835                                 c->xref_dead_list = ref;
836                                 xref_dead_count++;
837                                 continue;
838                         }
839                         /* At this point, ref->xid and ref->ino contain XID and inode number.
840                            ref->xd and ref->ic are not valid yet. */
841                         xd = jffs2_find_xattr_datum(c, ref->xid);
842                         ic = jffs2_get_ino_cache(c, ref->ino);
843                         if (!xd || !ic || !ic->pino_nlink) {
844                                 dbg_xattr("xref(ino=%u, xid=%u, xseqno=%u) is orphan.\n",
845                                           ref->ino, ref->xid, ref->xseqno);
846                                 ref->xseqno |= XREF_DELETE_MARKER;
847                                 ref->next = c->xref_dead_list;
848                                 c->xref_dead_list = ref;
849                                 xref_orphan_count++;
850                                 continue;
851                         }
852                         ref->xd = xd;
853                         ref->ic = ic;
854                         atomic_inc(&xd->refcnt);
855                         ref->next = ic->xref;
856                         ic->xref = ref;
857                 }
858         }
859 
860         /* Phase.3 : Link unchecked xdatum to xattr_unchecked list */
861         for (i=0; i < XATTRINDEX_HASHSIZE; i++) {
862                 list_for_each_entry_safe(xd, _xd, &c->xattrindex[i], xindex) {
863                         xdatum_count++;
864                         list_del_init(&xd->xindex);
865                         if (!atomic_read(&xd->refcnt)) {
866                                 dbg_xattr("xdatum(xid=%u, version=%u) is orphan.\n",
867                                           xd->xid, xd->version);
868                                 xd->flags |= JFFS2_XFLAGS_DEAD;
869                                 list_add(&xd->xindex, &c->xattr_unchecked);
870                                 xdatum_orphan_count++;
871                                 continue;
872                         }
873                         if (is_xattr_datum_unchecked(c, xd)) {
874                                 dbg_xattr("unchecked xdatum(xid=%u, version=%u)\n",
875                                           xd->xid, xd->version);
876                                 list_add(&xd->xindex, &c->xattr_unchecked);
877                                 xdatum_unchecked_count++;
878                         }
879                 }
880         }
881         /* build complete */
882         JFFS2_NOTICE("complete building xattr subsystem, %u of xdatum"
883                      " (%u unchecked, %u orphan) and "
884                      "%u of xref (%u dead, %u orphan) found.\n",
885                      xdatum_count, xdatum_unchecked_count, xdatum_orphan_count,
886                      xref_count, xref_dead_count, xref_orphan_count);
887 }
888 
889 struct jffs2_xattr_datum *jffs2_setup_xattr_datum(struct jffs2_sb_info *c,
890                                                   uint32_t xid, uint32_t version)
891 {
892         struct jffs2_xattr_datum *xd;
893 
894         xd = jffs2_find_xattr_datum(c, xid);
895         if (!xd) {
896                 xd = jffs2_alloc_xattr_datum();
897                 if (!xd)
898                         return ERR_PTR(-ENOMEM);
899                 xd->xid = xid;
900                 xd->version = version;
901                 if (xd->xid > c->highest_xid)
902                         c->highest_xid = xd->xid;
903                 list_add_tail(&xd->xindex, &c->xattrindex[xid % XATTRINDEX_HASHSIZE]);
904         }
905         return xd;
906 }
907 
908 /* -------- xattr subsystem functions ---------------
909  * xprefix_to_handler(xprefix)
910  *   is used to translate xprefix into xattr_handler.
911  * jffs2_listxattr(dentry, buffer, size)
912  *   is an implementation of listxattr handler on jffs2.
913  * do_jffs2_getxattr(inode, xprefix, xname, buffer, size)
914  *   is an implementation of getxattr handler on jffs2.
915  * do_jffs2_setxattr(inode, xprefix, xname, buffer, size, flags)
916  *   is an implementation of setxattr handler on jffs2.
917  * -------------------------------------------------- */
918 const struct xattr_handler *jffs2_xattr_handlers[] = {
919         &jffs2_user_xattr_handler,
920 #ifdef CONFIG_JFFS2_FS_SECURITY
921         &jffs2_security_xattr_handler,
922 #endif
923 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
924         &posix_acl_access_xattr_handler,
925         &posix_acl_default_xattr_handler,
926 #endif
927         &jffs2_trusted_xattr_handler,
928         NULL
929 };
930 
931 static const struct xattr_handler *xprefix_to_handler(int xprefix) {
932         const struct xattr_handler *ret;
933 
934         switch (xprefix) {
935         case JFFS2_XPREFIX_USER:
936                 ret = &jffs2_user_xattr_handler;
937                 break;
938 #ifdef CONFIG_JFFS2_FS_SECURITY
939         case JFFS2_XPREFIX_SECURITY:
940                 ret = &jffs2_security_xattr_handler;
941                 break;
942 #endif
943 #ifdef CONFIG_JFFS2_FS_POSIX_ACL
944         case JFFS2_XPREFIX_ACL_ACCESS:
945                 ret = &posix_acl_access_xattr_handler;
946                 break;
947         case JFFS2_XPREFIX_ACL_DEFAULT:
948                 ret = &posix_acl_default_xattr_handler;
949                 break;
950 #endif
951         case JFFS2_XPREFIX_TRUSTED:
952                 ret = &jffs2_trusted_xattr_handler;
953                 break;
954         default:
955                 ret = NULL;
956                 break;
957         }
958         return ret;
959 }
960 
961 ssize_t jffs2_listxattr(struct dentry *dentry, char *buffer, size_t size)
962 {
963         struct inode *inode = d_inode(dentry);
964         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
965         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
966         struct jffs2_inode_cache *ic = f->inocache;
967         struct jffs2_xattr_ref *ref, **pref;
968         struct jffs2_xattr_datum *xd;
969         const struct xattr_handler *xhandle;
970         const char *prefix;
971         ssize_t prefix_len, len, rc;
972         int retry = 0;
973 
974         rc = check_xattr_ref_inode(c, ic);
975         if (unlikely(rc))
976                 return rc;
977 
978         down_read(&c->xattr_sem);
979  retry:
980         len = 0;
981         for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
982                 BUG_ON(ref->ic != ic);
983                 xd = ref->xd;
984                 if (!xd->xname) {
985                         /* xdatum is unchached */
986                         if (!retry) {
987                                 retry = 1;
988                                 up_read(&c->xattr_sem);
989                                 down_write(&c->xattr_sem);
990                                 goto retry;
991                         } else {
992                                 rc = load_xattr_datum(c, xd);
993                                 if (unlikely(rc > 0)) {
994                                         *pref = ref->next;
995                                         delete_xattr_ref(c, ref);
996                                         goto retry;
997                                 } else if (unlikely(rc < 0))
998                                         goto out;
999                         }
1000                 }
1001                 xhandle = xprefix_to_handler(xd->xprefix);
1002                 if (!xhandle || (xhandle->list && !xhandle->list(dentry)))
1003                         continue;
1004                 prefix = xhandle->prefix ?: xhandle->name;
1005                 prefix_len = strlen(prefix);
1006                 rc = prefix_len + xd->name_len + 1;
1007 
1008                 if (buffer) {
1009                         if (rc > size - len) {
1010                                 rc = -ERANGE;
1011                                 goto out;
1012                         }
1013                         memcpy(buffer, prefix, prefix_len);
1014                         buffer += prefix_len;
1015                         memcpy(buffer, xd->xname, xd->name_len);
1016                         buffer += xd->name_len;
1017                         *buffer++ = 0;
1018                 }
1019                 len += rc;
1020         }
1021         rc = len;
1022  out:
1023         if (!retry) {
1024                 up_read(&c->xattr_sem);
1025         } else {
1026                 up_write(&c->xattr_sem);
1027         }
1028         return rc;
1029 }
1030 
1031 int do_jffs2_getxattr(struct inode *inode, int xprefix, const char *xname,
1032                       char *buffer, size_t size)
1033 {
1034         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
1035         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
1036         struct jffs2_inode_cache *ic = f->inocache;
1037         struct jffs2_xattr_datum *xd;
1038         struct jffs2_xattr_ref *ref, **pref;
1039         int rc, retry = 0;
1040 
1041         rc = check_xattr_ref_inode(c, ic);
1042         if (unlikely(rc))
1043                 return rc;
1044 
1045         down_read(&c->xattr_sem);
1046  retry:
1047         for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
1048                 BUG_ON(ref->ic!=ic);
1049 
1050                 xd = ref->xd;
1051                 if (xd->xprefix != xprefix)
1052                         continue;
1053                 if (!xd->xname) {
1054                         /* xdatum is unchached */
1055                         if (!retry) {
1056                                 retry = 1;
1057                                 up_read(&c->xattr_sem);
1058                                 down_write(&c->xattr_sem);
1059                                 goto retry;
1060                         } else {
1061                                 rc = load_xattr_datum(c, xd);
1062                                 if (unlikely(rc > 0)) {
1063                                         *pref = ref->next;
1064                                         delete_xattr_ref(c, ref);
1065                                         goto retry;
1066                                 } else if (unlikely(rc < 0)) {
1067                                         goto out;
1068                                 }
1069                         }
1070                 }
1071                 if (!strcmp(xname, xd->xname)) {
1072                         rc = xd->value_len;
1073                         if (buffer) {
1074                                 if (size < rc) {
1075                                         rc = -ERANGE;
1076                                 } else {
1077                                         memcpy(buffer, xd->xvalue, rc);
1078                                 }
1079                         }
1080                         goto out;
1081                 }
1082         }
1083         rc = -ENODATA;
1084  out:
1085         if (!retry) {
1086                 up_read(&c->xattr_sem);
1087         } else {
1088                 up_write(&c->xattr_sem);
1089         }
1090         return rc;
1091 }
1092 
1093 int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
1094                       const char *buffer, size_t size, int flags)
1095 {
1096         struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
1097         struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
1098         struct jffs2_inode_cache *ic = f->inocache;
1099         struct jffs2_xattr_datum *xd;
1100         struct jffs2_xattr_ref *ref, *newref, **pref;
1101         uint32_t length, request;
1102         int rc;
1103 
1104         rc = check_xattr_ref_inode(c, ic);
1105         if (unlikely(rc))
1106                 return rc;
1107 
1108         request = PAD(sizeof(struct jffs2_raw_xattr) + strlen(xname) + 1 + size);
1109         rc = jffs2_reserve_space(c, request, &length,
1110                                  ALLOC_NORMAL, JFFS2_SUMMARY_XATTR_SIZE);
1111         if (rc) {
1112                 JFFS2_WARNING("jffs2_reserve_space()=%d, request=%u\n", rc, request);
1113                 return rc;
1114         }
1115 
1116         /* Find existing xattr */
1117         down_write(&c->xattr_sem);
1118  retry:
1119         for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
1120                 xd = ref->xd;
1121                 if (xd->xprefix != xprefix)
1122                         continue;
1123                 if (!xd->xname) {
1124                         rc = load_xattr_datum(c, xd);
1125                         if (unlikely(rc > 0)) {
1126                                 *pref = ref->next;
1127                                 delete_xattr_ref(c, ref);
1128                                 goto retry;
1129                         } else if (unlikely(rc < 0))
1130                                 goto out;
1131                 }
1132                 if (!strcmp(xd->xname, xname)) {
1133                         if (flags & XATTR_CREATE) {
1134                                 rc = -EEXIST;
1135                                 goto out;
1136                         }
1137                         if (!buffer) {
1138                                 ref->ino = ic->ino;
1139                                 ref->xid = xd->xid;
1140                                 ref->xseqno |= XREF_DELETE_MARKER;
1141                                 rc = save_xattr_ref(c, ref);
1142                                 if (!rc) {
1143                                         *pref = ref->next;
1144                                         spin_lock(&c->erase_completion_lock);
1145                                         ref->next = c->xref_dead_list;
1146                                         c->xref_dead_list = ref;
1147                                         spin_unlock(&c->erase_completion_lock);
1148                                         unrefer_xattr_datum(c, xd);
1149                                 } else {
1150                                         ref->ic = ic;
1151                                         ref->xd = xd;
1152                                         ref->xseqno &= ~XREF_DELETE_MARKER;
1153                                 }
1154                                 goto out;
1155                         }
1156                         goto found;
1157                 }
1158         }
1159         /* not found */
1160         if (flags & XATTR_REPLACE) {
1161                 rc = -ENODATA;
1162                 goto out;
1163         }
1164         if (!buffer) {
1165                 rc = -ENODATA;
1166                 goto out;
1167         }
1168  found:
1169         xd = create_xattr_datum(c, xprefix, xname, buffer, size);
1170         if (IS_ERR(xd)) {
1171                 rc = PTR_ERR(xd);
1172                 goto out;
1173         }
1174         up_write(&c->xattr_sem);
1175         jffs2_complete_reservation(c);
1176 
1177         /* create xattr_ref */
1178         request = PAD(sizeof(struct jffs2_raw_xref));
1179         rc = jffs2_reserve_space(c, request, &length,
1180                                  ALLOC_NORMAL, JFFS2_SUMMARY_XREF_SIZE);
1181         down_write(&c->xattr_sem);
1182         if (rc) {
1183                 JFFS2_WARNING("jffs2_reserve_space()=%d, request=%u\n", rc, request);
1184                 unrefer_xattr_datum(c, xd);
1185                 up_write(&c->xattr_sem);
1186                 return rc;
1187         }
1188         if (ref)
1189                 *pref = ref->next;
1190         newref = create_xattr_ref(c, ic, xd);
1191         if (IS_ERR(newref)) {
1192                 if (ref) {
1193                         ref->next = ic->xref;
1194                         ic->xref = ref;
1195                 }
1196                 rc = PTR_ERR(newref);
1197                 unrefer_xattr_datum(c, xd);
1198         } else if (ref) {
1199                 delete_xattr_ref(c, ref);
1200         }
1201  out:
1202         up_write(&c->xattr_sem);
1203         jffs2_complete_reservation(c);
1204         return rc;
1205 }
1206 
1207 /* -------- garbage collector functions -------------
1208  * jffs2_garbage_collect_xattr_datum(c, xd, raw)
1209  *   is used to move xdatum into new node.
1210  * jffs2_garbage_collect_xattr_ref(c, ref, raw)
1211  *   is used to move xref into new node.
1212  * jffs2_verify_xattr(c)
1213  *   is used to call do_verify_xattr_datum() before garbage collecting.
1214  * jffs2_release_xattr_datum(c, xd)
1215  *   is used to release an in-memory object of xdatum.
1216  * jffs2_release_xattr_ref(c, ref)
1217  *   is used to release an in-memory object of xref.
1218  * -------------------------------------------------- */
1219 int jffs2_garbage_collect_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd,
1220                                       struct jffs2_raw_node_ref *raw)
1221 {
1222         uint32_t totlen, length, old_ofs;
1223         int rc = 0;
1224 
1225         down_write(&c->xattr_sem);
1226         if (xd->node != raw)
1227                 goto out;
1228         if (xd->flags & (JFFS2_XFLAGS_DEAD|JFFS2_XFLAGS_INVALID))
1229                 goto out;
1230 
1231         rc = load_xattr_datum(c, xd);
1232         if (unlikely(rc)) {
1233                 rc = (rc > 0) ? 0 : rc;
1234                 goto out;
1235         }
1236         old_ofs = ref_offset(xd->node);
1237         totlen = PAD(sizeof(struct jffs2_raw_xattr)
1238                         + xd->name_len + 1 + xd->value_len);
1239         rc = jffs2_reserve_space_gc(c, totlen, &length, JFFS2_SUMMARY_XATTR_SIZE);
1240         if (rc) {
1241                 JFFS2_WARNING("jffs2_reserve_space_gc()=%d, request=%u\n", rc, totlen);
1242                 goto out;
1243         }
1244         rc = save_xattr_datum(c, xd);
1245         if (!rc)
1246                 dbg_xattr("xdatum (xid=%u, version=%u) GC'ed from %#08x to %08x\n",
1247                           xd->xid, xd->version, old_ofs, ref_offset(xd->node));
1248  out:
1249         if (!rc)
1250                 jffs2_mark_node_obsolete(c, raw);
1251         up_write(&c->xattr_sem);
1252         return rc;
1253 }
1254 
1255 int jffs2_garbage_collect_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref,
1256                                     struct jffs2_raw_node_ref *raw)
1257 {
1258         uint32_t totlen, length, old_ofs;
1259         int rc = 0;
1260 
1261         down_write(&c->xattr_sem);
1262         BUG_ON(!ref->node);
1263 
1264         if (ref->node != raw)
1265                 goto out;
1266         if (is_xattr_ref_dead(ref) && (raw->next_in_ino == (void *)ref))
1267                 goto out;
1268 
1269         old_ofs = ref_offset(ref->node);
1270         totlen = ref_totlen(c, c->gcblock, ref->node);
1271 
1272         rc = jffs2_reserve_space_gc(c, totlen, &length, JFFS2_SUMMARY_XREF_SIZE);
1273         if (rc) {
1274                 JFFS2_WARNING("%s: jffs2_reserve_space_gc() = %d, request = %u\n",
1275                               __func__, rc, totlen);
1276                 goto out;
1277         }
1278         rc = save_xattr_ref(c, ref);
1279         if (!rc)
1280                 dbg_xattr("xref (ino=%u, xid=%u) GC'ed from %#08x to %08x\n",
1281                           ref->ic->ino, ref->xd->xid, old_ofs, ref_offset(ref->node));
1282  out:
1283         if (!rc)
1284                 jffs2_mark_node_obsolete(c, raw);
1285         up_write(&c->xattr_sem);
1286         return rc;
1287 }
1288 
1289 int jffs2_verify_xattr(struct jffs2_sb_info *c)
1290 {
1291         struct jffs2_xattr_datum *xd, *_xd;
1292         struct jffs2_eraseblock *jeb;
1293         struct jffs2_raw_node_ref *raw;
1294         uint32_t totlen;
1295         int rc;
1296 
1297         down_write(&c->xattr_sem);
1298         list_for_each_entry_safe(xd, _xd, &c->xattr_unchecked, xindex) {
1299                 rc = do_verify_xattr_datum(c, xd);
1300                 if (rc < 0)
1301                         continue;
1302                 list_del_init(&xd->xindex);
1303                 spin_lock(&c->erase_completion_lock);
1304                 for (raw=xd->node; raw != (void *)xd; raw=raw->next_in_ino) {
1305                         if (ref_flags(raw) != REF_UNCHECKED)
1306                                 continue;
1307                         jeb = &c->blocks[ref_offset(raw) / c->sector_size];
1308                         totlen = PAD(ref_totlen(c, jeb, raw));
1309                         c->unchecked_size -= totlen; c->used_size += totlen;
1310                         jeb->unchecked_size -= totlen; jeb->used_size += totlen;
1311                         raw->flash_offset = ref_offset(raw)
1312                                 | ((xd->node == (void *)raw) ? REF_PRISTINE : REF_NORMAL);
1313                 }
1314                 if (xd->flags & JFFS2_XFLAGS_DEAD)
1315                         list_add(&xd->xindex, &c->xattr_dead_list);
1316                 spin_unlock(&c->erase_completion_lock);
1317         }
1318         up_write(&c->xattr_sem);
1319         return list_empty(&c->xattr_unchecked) ? 1 : 0;
1320 }
1321 
1322 void jffs2_release_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
1323 {
1324         /* must be called under spin_lock(&c->erase_completion_lock) */
1325         if (atomic_read(&xd->refcnt) || xd->node != (void *)xd)
1326                 return;
1327 
1328         list_del(&xd->xindex);
1329         jffs2_free_xattr_datum(xd);
1330 }
1331 
1332 void jffs2_release_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
1333 {
1334         /* must be called under spin_lock(&c->erase_completion_lock) */
1335         struct jffs2_xattr_ref *tmp, **ptmp;
1336 
1337         if (ref->node != (void *)ref)
1338                 return;
1339 
1340         for (tmp=c->xref_dead_list, ptmp=&c->xref_dead_list; tmp; ptmp=&tmp->next, tmp=tmp->next) {
1341                 if (ref == tmp) {
1342                         *ptmp = tmp->next;
1343                         break;
1344                 }
1345         }
1346         jffs2_free_xattr_ref(ref);
1347 }
1348 

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