This commit was manufactured by cvs2svn to create branch 'vserver'.
[linux-2.6.git] / fs / jffs2 / xattr.c
diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
new file mode 100644 (file)
index 0000000..4da09ce
--- /dev/null
@@ -0,0 +1,1324 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright (C) 2006  NEC Corporation
+ *
+ * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/crc32.h>
+#include <linux/jffs2.h>
+#include <linux/xattr.h>
+#include <linux/mtd/mtd.h>
+#include "nodelist.h"
+/* -------- xdatum related functions ----------------
+ * xattr_datum_hashkey(xprefix, xname, xvalue, xsize)
+ *   is used to calcurate xdatum hashkey. The reminder of hashkey into XATTRINDEX_HASHSIZE is
+ *   the index of the xattr name/value pair cache (c->xattrindex).
+ * is_xattr_datum_unchecked(c, xd)
+ *   returns 1, if xdatum contains any unchecked raw nodes. if all raw nodes are not
+ *   unchecked, it returns 0.
+ * unload_xattr_datum(c, xd)
+ *   is used to release xattr name/value pair and detach from c->xattrindex.
+ * reclaim_xattr_datum(c)
+ *   is used to reclaim xattr name/value pairs on the xattr name/value pair cache when
+ *   memory usage by cache is over c->xdatum_mem_threshold. Currentry, this threshold 
+ *   is hard coded as 32KiB.
+ * do_verify_xattr_datum(c, xd)
+ *   is used to load the xdatum informations without name/value pair from the medium.
+ *   It's necessary once, because those informations are not collected during mounting
+ *   process when EBS is enabled.
+ *   0 will be returned, if success. An negative return value means recoverable error, and
+ *   positive return value means unrecoverable error. Thus, caller must remove this xdatum
+ *   and xref when it returned positive value.
+ * do_load_xattr_datum(c, xd)
+ *   is used to load name/value pair from the medium.
+ *   The meanings of return value is same as do_verify_xattr_datum().
+ * load_xattr_datum(c, xd)
+ *   is used to be as a wrapper of do_verify_xattr_datum() and do_load_xattr_datum().
+ *   If xd need to call do_verify_xattr_datum() at first, it's called before calling
+ *   do_load_xattr_datum(). The meanings of return value is same as do_verify_xattr_datum().
+ * save_xattr_datum(c, xd)
+ *   is used to write xdatum to medium. xd->version will be incremented.
+ * create_xattr_datum(c, xprefix, xname, xvalue, xsize)
+ *   is used to create new xdatum and write to medium.
+ * unrefer_xattr_datum(c, xd)
+ *   is used to delete a xdatum. When nobody refers this xdatum, JFFS2_XFLAGS_DEAD
+ *   is set on xd->flags and chained xattr_dead_list or release it immediately.
+ *   In the first case, the garbage collector release it later.
+ * -------------------------------------------------- */
+static uint32_t xattr_datum_hashkey(int xprefix, const char *xname, const char *xvalue, int xsize)
+{
+       int name_len = strlen(xname);
+
+       return crc32(xprefix, xname, name_len) ^ crc32(xprefix, xvalue, xsize);
+}
+
+static int is_xattr_datum_unchecked(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
+{
+       struct jffs2_raw_node_ref *raw;
+       int rc = 0;
+
+       spin_lock(&c->erase_completion_lock);
+       for (raw=xd->node; raw != (void *)xd; raw=raw->next_in_ino) {
+               if (ref_flags(raw) == REF_UNCHECKED) {
+                       rc = 1;
+                       break;
+               }
+       }
+       spin_unlock(&c->erase_completion_lock);
+       return rc;
+}
+
+static void unload_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
+{
+       /* must be called under down_write(xattr_sem) */
+       D1(dbg_xattr("%s: xid=%u, version=%u\n", __FUNCTION__, xd->xid, xd->version));
+       if (xd->xname) {
+               c->xdatum_mem_usage -= (xd->name_len + 1 + xd->value_len);
+               kfree(xd->xname);
+       }
+
+       list_del_init(&xd->xindex);
+       xd->hashkey = 0;
+       xd->xname = NULL;
+       xd->xvalue = NULL;
+}
+
+static void reclaim_xattr_datum(struct jffs2_sb_info *c)
+{
+       /* must be called under down_write(xattr_sem) */
+       struct jffs2_xattr_datum *xd, *_xd;
+       uint32_t target, before;
+       static int index = 0;
+       int count;
+
+       if (c->xdatum_mem_threshold > c->xdatum_mem_usage)
+               return;
+
+       before = c->xdatum_mem_usage;
+       target = c->xdatum_mem_usage * 4 / 5; /* 20% reduction */
+       for (count = 0; count < XATTRINDEX_HASHSIZE; count++) {
+               list_for_each_entry_safe(xd, _xd, &c->xattrindex[index], xindex) {
+                       if (xd->flags & JFFS2_XFLAGS_HOT) {
+                               xd->flags &= ~JFFS2_XFLAGS_HOT;
+                       } else if (!(xd->flags & JFFS2_XFLAGS_BIND)) {
+                               unload_xattr_datum(c, xd);
+                       }
+                       if (c->xdatum_mem_usage <= target)
+                               goto out;
+               }
+               index = (index+1) % XATTRINDEX_HASHSIZE;
+       }
+ out:
+       JFFS2_NOTICE("xdatum_mem_usage from %u byte to %u byte (%u byte reclaimed)\n",
+                    before, c->xdatum_mem_usage, before - c->xdatum_mem_usage);
+}
+
+static int do_verify_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
+{
+       /* must be called under down_write(xattr_sem) */
+       struct jffs2_eraseblock *jeb;
+       struct jffs2_raw_node_ref *raw;
+       struct jffs2_raw_xattr rx;
+       size_t readlen;
+       uint32_t crc, offset, totlen;
+       int rc;
+
+       spin_lock(&c->erase_completion_lock);
+       offset = ref_offset(xd->node);
+       if (ref_flags(xd->node) == REF_PRISTINE)
+               goto complete;
+       spin_unlock(&c->erase_completion_lock);
+
+       rc = jffs2_flash_read(c, offset, sizeof(rx), &readlen, (char *)&rx);
+       if (rc || readlen != sizeof(rx)) {
+               JFFS2_WARNING("jffs2_flash_read()=%d, req=%zu, read=%zu at %#08x\n",
+                             rc, sizeof(rx), readlen, offset);
+               return rc ? rc : -EIO;
+       }
+       crc = crc32(0, &rx, sizeof(rx) - 4);
+       if (crc != je32_to_cpu(rx.node_crc)) {
+               JFFS2_ERROR("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
+                           offset, je32_to_cpu(rx.hdr_crc), crc);
+               xd->flags |= JFFS2_XFLAGS_INVALID;
+               return EIO;
+       }
+       totlen = PAD(sizeof(rx) + rx.name_len + 1 + je16_to_cpu(rx.value_len));
+       if (je16_to_cpu(rx.magic) != JFFS2_MAGIC_BITMASK
+           || je16_to_cpu(rx.nodetype) != JFFS2_NODETYPE_XATTR
+           || je32_to_cpu(rx.totlen) != totlen
+           || je32_to_cpu(rx.xid) != xd->xid
+           || je32_to_cpu(rx.version) != xd->version) {
+               JFFS2_ERROR("inconsistent xdatum at %#08x, magic=%#04x/%#04x, "
+                           "nodetype=%#04x/%#04x, totlen=%u/%u, xid=%u/%u, version=%u/%u\n",
+                           offset, je16_to_cpu(rx.magic), JFFS2_MAGIC_BITMASK,
+                           je16_to_cpu(rx.nodetype), JFFS2_NODETYPE_XATTR,
+                           je32_to_cpu(rx.totlen), totlen,
+                           je32_to_cpu(rx.xid), xd->xid,
+                           je32_to_cpu(rx.version), xd->version);
+               xd->flags |= JFFS2_XFLAGS_INVALID;
+               return EIO;
+       }
+       xd->xprefix = rx.xprefix;
+       xd->name_len = rx.name_len;
+       xd->value_len = je16_to_cpu(rx.value_len);
+       xd->data_crc = je32_to_cpu(rx.data_crc);
+
+       spin_lock(&c->erase_completion_lock);
+ complete:
+       for (raw=xd->node; raw != (void *)xd; raw=raw->next_in_ino) {
+               jeb = &c->blocks[ref_offset(raw) / c->sector_size];
+               totlen = PAD(ref_totlen(c, jeb, raw));
+               if (ref_flags(raw) == REF_UNCHECKED) {
+                       c->unchecked_size -= totlen; c->used_size += totlen;
+                       jeb->unchecked_size -= totlen; jeb->used_size += totlen;
+               }
+               raw->flash_offset = ref_offset(raw) | ((xd->node==raw) ? REF_PRISTINE : REF_NORMAL);
+       }
+       spin_unlock(&c->erase_completion_lock);
+
+       /* unchecked xdatum is chained with c->xattr_unchecked */
+       list_del_init(&xd->xindex);
+
+       dbg_xattr("success on verfying xdatum (xid=%u, version=%u)\n",
+                 xd->xid, xd->version);
+
+       return 0;
+}
+
+static int do_load_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
+{
+       /* must be called under down_write(xattr_sem) */
+       char *data;
+       size_t readlen;
+       uint32_t crc, length;
+       int i, ret, retry = 0;
+
+       BUG_ON(ref_flags(xd->node) != REF_PRISTINE);
+       BUG_ON(!list_empty(&xd->xindex));
+ retry:
+       length = xd->name_len + 1 + xd->value_len;
+       data = kmalloc(length, GFP_KERNEL);
+       if (!data)
+               return -ENOMEM;
+
+       ret = jffs2_flash_read(c, ref_offset(xd->node)+sizeof(struct jffs2_raw_xattr),
+                              length, &readlen, data);
+
+       if (ret || length!=readlen) {
+               JFFS2_WARNING("jffs2_flash_read() returned %d, request=%d, readlen=%zu, at %#08x\n",
+                             ret, length, readlen, ref_offset(xd->node));
+               kfree(data);
+               return ret ? ret : -EIO;
+       }
+
+       data[xd->name_len] = '\0';
+       crc = crc32(0, data, length);
+       if (crc != xd->data_crc) {
+               JFFS2_WARNING("node CRC failed (JFFS2_NODETYPE_XREF)"
+                             " at %#08x, read: 0x%08x calculated: 0x%08x\n",
+                             ref_offset(xd->node), xd->data_crc, crc);
+               kfree(data);
+               xd->flags |= JFFS2_XFLAGS_INVALID;
+               return EIO;
+       }
+
+       xd->flags |= JFFS2_XFLAGS_HOT;
+       xd->xname = data;
+       xd->xvalue = data + xd->name_len+1;
+
+       c->xdatum_mem_usage += length;
+
+       xd->hashkey = xattr_datum_hashkey(xd->xprefix, xd->xname, xd->xvalue, xd->value_len);
+       i = xd->hashkey % XATTRINDEX_HASHSIZE;
+       list_add(&xd->xindex, &c->xattrindex[i]);
+       if (!retry) {
+               retry = 1;
+               reclaim_xattr_datum(c);
+               if (!xd->xname)
+                       goto retry;
+       }
+
+       dbg_xattr("success on loading xdatum (xid=%u, xprefix=%u, xname='%s')\n",
+                 xd->xid, xd->xprefix, xd->xname);
+
+       return 0;
+}
+
+static int load_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
+{
+       /* must be called under down_write(xattr_sem);
+        * rc < 0 : recoverable error, try again
+        * rc = 0 : success
+        * rc > 0 : Unrecoverable error, this node should be deleted.
+        */
+       int rc = 0;
+
+       BUG_ON(xd->flags & JFFS2_XFLAGS_DEAD);
+       if (xd->xname)
+               return 0;
+       if (xd->flags & JFFS2_XFLAGS_INVALID)
+               return EIO;
+       if (unlikely(is_xattr_datum_unchecked(c, xd)))
+               rc = do_verify_xattr_datum(c, xd);
+       if (!rc)
+               rc = do_load_xattr_datum(c, xd);
+       return rc;
+}
+
+static int save_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
+{
+       /* must be called under down_write(xattr_sem) */
+       struct jffs2_raw_xattr rx;
+       struct kvec vecs[2];
+       size_t length;
+       int rc, totlen;
+       uint32_t phys_ofs = write_ofs(c);
+
+       BUG_ON(!xd->xname);
+       BUG_ON(xd->flags & (JFFS2_XFLAGS_DEAD|JFFS2_XFLAGS_INVALID));
+
+       vecs[0].iov_base = &rx;
+       vecs[0].iov_len = sizeof(rx);
+       vecs[1].iov_base = xd->xname;
+       vecs[1].iov_len = xd->name_len + 1 + xd->value_len;
+       totlen = vecs[0].iov_len + vecs[1].iov_len;
+
+       /* Setup raw-xattr */
+       memset(&rx, 0, sizeof(rx));
+       rx.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
+       rx.nodetype = cpu_to_je16(JFFS2_NODETYPE_XATTR);
+       rx.totlen = cpu_to_je32(PAD(totlen));
+       rx.hdr_crc = cpu_to_je32(crc32(0, &rx, sizeof(struct jffs2_unknown_node) - 4));
+
+       rx.xid = cpu_to_je32(xd->xid);
+       rx.version = cpu_to_je32(++xd->version);
+       rx.xprefix = xd->xprefix;
+       rx.name_len = xd->name_len;
+       rx.value_len = cpu_to_je16(xd->value_len);
+       rx.data_crc = cpu_to_je32(crc32(0, vecs[1].iov_base, vecs[1].iov_len));
+       rx.node_crc = cpu_to_je32(crc32(0, &rx, sizeof(struct jffs2_raw_xattr) - 4));
+
+       rc = jffs2_flash_writev(c, vecs, 2, phys_ofs, &length, 0);
+       if (rc || totlen != length) {
+               JFFS2_WARNING("jffs2_flash_writev()=%d, req=%u, wrote=%zu, at %#08x\n",
+                             rc, totlen, length, phys_ofs);
+               rc = rc ? rc : -EIO;
+               if (length)
+                       jffs2_add_physical_node_ref(c, phys_ofs | REF_OBSOLETE, PAD(totlen), NULL);
+
+               return rc;
+       }
+       /* success */
+       jffs2_add_physical_node_ref(c, phys_ofs | REF_PRISTINE, PAD(totlen), (void *)xd);
+
+       dbg_xattr("success on saving xdatum (xid=%u, version=%u, xprefix=%u, xname='%s')\n",
+                 xd->xid, xd->version, xd->xprefix, xd->xname);
+
+       return 0;
+}
+
+static struct jffs2_xattr_datum *create_xattr_datum(struct jffs2_sb_info *c,
+                                                   int xprefix, const char *xname,
+                                                   const char *xvalue, int xsize)
+{
+       /* must be called under down_write(xattr_sem) */
+       struct jffs2_xattr_datum *xd;
+       uint32_t hashkey, name_len;
+       char *data;
+       int i, rc;
+
+       /* Search xattr_datum has same xname/xvalue by index */
+       hashkey = xattr_datum_hashkey(xprefix, xname, xvalue, xsize);
+       i = hashkey % XATTRINDEX_HASHSIZE;
+       list_for_each_entry(xd, &c->xattrindex[i], xindex) {
+               if (xd->hashkey==hashkey
+                   && xd->xprefix==xprefix
+                   && xd->value_len==xsize
+                   && !strcmp(xd->xname, xname)
+                   && !memcmp(xd->xvalue, xvalue, xsize)) {
+                       atomic_inc(&xd->refcnt);
+                       return xd;
+               }
+       }
+
+       /* Not found, Create NEW XATTR-Cache */
+       name_len = strlen(xname);
+
+       xd = jffs2_alloc_xattr_datum();
+       if (!xd)
+               return ERR_PTR(-ENOMEM);
+
+       data = kmalloc(name_len + 1 + xsize, GFP_KERNEL);
+       if (!data) {
+               jffs2_free_xattr_datum(xd);
+               return ERR_PTR(-ENOMEM);
+       }
+       strcpy(data, xname);
+       memcpy(data + name_len + 1, xvalue, xsize);
+
+       atomic_set(&xd->refcnt, 1);
+       xd->xid = ++c->highest_xid;
+       xd->flags |= JFFS2_XFLAGS_HOT;
+       xd->xprefix = xprefix;
+
+       xd->hashkey = hashkey;
+       xd->xname = data;
+       xd->xvalue = data + name_len + 1;
+       xd->name_len = name_len;
+       xd->value_len = xsize;
+       xd->data_crc = crc32(0, data, xd->name_len + 1 + xd->value_len);
+
+       rc = save_xattr_datum(c, xd);
+       if (rc) {
+               kfree(xd->xname);
+               jffs2_free_xattr_datum(xd);
+               return ERR_PTR(rc);
+       }
+
+       /* Insert Hash Index */
+       i = hashkey % XATTRINDEX_HASHSIZE;
+       list_add(&xd->xindex, &c->xattrindex[i]);
+
+       c->xdatum_mem_usage += (xd->name_len + 1 + xd->value_len);
+       reclaim_xattr_datum(c);
+
+       return xd;
+}
+
+static void unrefer_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
+{
+       /* must be called under down_write(xattr_sem) */
+       if (atomic_dec_and_lock(&xd->refcnt, &c->erase_completion_lock)) {
+               uint32_t xid = xd->xid, version = xd->version;
+
+               unload_xattr_datum(c, xd);
+               xd->flags |= JFFS2_XFLAGS_DEAD;
+               if (xd->node == (void *)xd) {
+                       BUG_ON(!(xd->flags & JFFS2_XFLAGS_INVALID));
+                       jffs2_free_xattr_datum(xd);
+               } else {
+                       list_add(&xd->xindex, &c->xattr_dead_list);
+               }
+               spin_unlock(&c->erase_completion_lock);
+
+               dbg_xattr("xdatum(xid=%u, version=%u) was removed.\n", xid, version);
+       }
+}
+
+/* -------- xref related functions ------------------
+ * verify_xattr_ref(c, ref)
+ *   is used to load xref information from medium. Because summary data does not
+ *   contain xid/ino, it's necessary to verify once while mounting process.
+ * save_xattr_ref(c, ref)
+ *   is used to write xref to medium. If delete marker is marked, it write
+ *   a delete marker of xref into medium.
+ * create_xattr_ref(c, ic, xd)
+ *   is used to create a new xref and write to medium.
+ * delete_xattr_ref(c, ref)
+ *   is used to delete jffs2_xattr_ref. It marks xref XREF_DELETE_MARKER,
+ *   and allows GC to reclaim those physical nodes.
+ * jffs2_xattr_delete_inode(c, ic)
+ *   is called to remove xrefs related to obsolete inode when inode is unlinked.
+ * jffs2_xattr_free_inode(c, ic)
+ *   is called to release xattr related objects when unmounting. 
+ * check_xattr_ref_inode(c, ic)
+ *   is used to confirm inode does not have duplicate xattr name/value pair.
+ * -------------------------------------------------- */
+static int verify_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
+{
+       struct jffs2_eraseblock *jeb;
+       struct jffs2_raw_node_ref *raw;
+       struct jffs2_raw_xref rr;
+       size_t readlen;
+       uint32_t crc, offset, totlen;
+       int rc;
+
+       spin_lock(&c->erase_completion_lock);
+       if (ref_flags(ref->node) != REF_UNCHECKED)
+               goto complete;
+       offset = ref_offset(ref->node);
+       spin_unlock(&c->erase_completion_lock);
+
+       rc = jffs2_flash_read(c, offset, sizeof(rr), &readlen, (char *)&rr);
+       if (rc || sizeof(rr) != readlen) {
+               JFFS2_WARNING("jffs2_flash_read()=%d, req=%zu, read=%zu, at %#08x\n",
+                             rc, sizeof(rr), readlen, offset);
+               return rc ? rc : -EIO;
+       }
+       /* obsolete node */
+       crc = crc32(0, &rr, sizeof(rr) - 4);
+       if (crc != je32_to_cpu(rr.node_crc)) {
+               JFFS2_ERROR("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
+                           offset, je32_to_cpu(rr.node_crc), crc);
+               return EIO;
+       }
+       if (je16_to_cpu(rr.magic) != JFFS2_MAGIC_BITMASK
+           || je16_to_cpu(rr.nodetype) != JFFS2_NODETYPE_XREF
+           || je32_to_cpu(rr.totlen) != PAD(sizeof(rr))) {
+               JFFS2_ERROR("inconsistent xref at %#08x, magic=%#04x/%#04x, "
+                           "nodetype=%#04x/%#04x, totlen=%u/%zu\n",
+                           offset, je16_to_cpu(rr.magic), JFFS2_MAGIC_BITMASK,
+                           je16_to_cpu(rr.nodetype), JFFS2_NODETYPE_XREF,
+                           je32_to_cpu(rr.totlen), PAD(sizeof(rr)));
+               return EIO;
+       }
+       ref->ino = je32_to_cpu(rr.ino);
+       ref->xid = je32_to_cpu(rr.xid);
+       ref->xseqno = je32_to_cpu(rr.xseqno);
+       if (ref->xseqno > c->highest_xseqno)
+               c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
+
+       spin_lock(&c->erase_completion_lock);
+ complete:
+       for (raw=ref->node; raw != (void *)ref; raw=raw->next_in_ino) {
+               jeb = &c->blocks[ref_offset(raw) / c->sector_size];
+               totlen = PAD(ref_totlen(c, jeb, raw));
+               if (ref_flags(raw) == REF_UNCHECKED) {
+                       c->unchecked_size -= totlen; c->used_size += totlen;
+                       jeb->unchecked_size -= totlen; jeb->used_size += totlen;
+               }
+               raw->flash_offset = ref_offset(raw) | ((ref->node==raw) ? REF_PRISTINE : REF_NORMAL);
+       }
+       spin_unlock(&c->erase_completion_lock);
+
+       dbg_xattr("success on verifying xref (ino=%u, xid=%u) at %#08x\n",
+                 ref->ino, ref->xid, ref_offset(ref->node));
+       return 0;
+}
+
+static int save_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
+{
+       /* must be called under down_write(xattr_sem) */
+       struct jffs2_raw_xref rr;
+       size_t length;
+       uint32_t xseqno, phys_ofs = write_ofs(c);
+       int ret;
+
+       rr.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
+       rr.nodetype = cpu_to_je16(JFFS2_NODETYPE_XREF);
+       rr.totlen = cpu_to_je32(PAD(sizeof(rr)));
+       rr.hdr_crc = cpu_to_je32(crc32(0, &rr, sizeof(struct jffs2_unknown_node) - 4));
+
+       xseqno = (c->highest_xseqno += 2);
+       if (is_xattr_ref_dead(ref)) {
+               xseqno |= XREF_DELETE_MARKER;
+               rr.ino = cpu_to_je32(ref->ino);
+               rr.xid = cpu_to_je32(ref->xid);
+       } else {
+               rr.ino = cpu_to_je32(ref->ic->ino);
+               rr.xid = cpu_to_je32(ref->xd->xid);
+       }
+       rr.xseqno = cpu_to_je32(xseqno);
+       rr.node_crc = cpu_to_je32(crc32(0, &rr, sizeof(rr) - 4));
+
+       ret = jffs2_flash_write(c, phys_ofs, sizeof(rr), &length, (char *)&rr);
+       if (ret || sizeof(rr) != length) {
+               JFFS2_WARNING("jffs2_flash_write() returned %d, request=%zu, retlen=%zu, at %#08x\n",
+                             ret, sizeof(rr), length, phys_ofs);
+               ret = ret ? ret : -EIO;
+               if (length)
+                       jffs2_add_physical_node_ref(c, phys_ofs | REF_OBSOLETE, PAD(sizeof(rr)), NULL);
+
+               return ret;
+       }
+       /* success */
+       ref->xseqno = xseqno;
+       jffs2_add_physical_node_ref(c, phys_ofs | REF_PRISTINE, PAD(sizeof(rr)), (void *)ref);
+
+       dbg_xattr("success on saving xref (ino=%u, xid=%u)\n", ref->ic->ino, ref->xd->xid);
+
+       return 0;
+}
+
+static struct jffs2_xattr_ref *create_xattr_ref(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic,
+                                               struct jffs2_xattr_datum *xd)
+{
+       /* must be called under down_write(xattr_sem) */
+       struct jffs2_xattr_ref *ref;
+       int ret;
+
+       ref = jffs2_alloc_xattr_ref();
+       if (!ref)
+               return ERR_PTR(-ENOMEM);
+       ref->ic = ic;
+       ref->xd = xd;
+
+       ret = save_xattr_ref(c, ref);
+       if (ret) {
+               jffs2_free_xattr_ref(ref);
+               return ERR_PTR(ret);
+       }
+
+       /* Chain to inode */
+       ref->next = ic->xref;
+       ic->xref = ref;
+
+       return ref; /* success */
+}
+
+static void delete_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
+{
+       /* must be called under down_write(xattr_sem) */
+       struct jffs2_xattr_datum *xd;
+
+       xd = ref->xd;
+       ref->xseqno |= XREF_DELETE_MARKER;
+       ref->ino = ref->ic->ino;
+       ref->xid = ref->xd->xid;
+       spin_lock(&c->erase_completion_lock);
+       ref->next = c->xref_dead_list;
+       c->xref_dead_list = ref;
+       spin_unlock(&c->erase_completion_lock);
+
+       dbg_xattr("xref(ino=%u, xid=%u, xseqno=%u) was removed.\n",
+                 ref->ino, ref->xid, ref->xseqno);
+
+       unrefer_xattr_datum(c, xd);
+}
+
+void jffs2_xattr_delete_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
+{
+       /* It's called from jffs2_clear_inode() on inode removing.
+          When an inode with XATTR is removed, those XATTRs must be removed. */
+       struct jffs2_xattr_ref *ref, *_ref;
+
+       if (!ic || ic->nlink > 0)
+               return;
+
+       down_write(&c->xattr_sem);
+       for (ref = ic->xref; ref; ref = _ref) {
+               _ref = ref->next;
+               delete_xattr_ref(c, ref);
+       }
+       ic->xref = NULL;
+       up_write(&c->xattr_sem);
+}
+
+void jffs2_xattr_free_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
+{
+       /* It's called from jffs2_free_ino_caches() until unmounting FS. */
+       struct jffs2_xattr_datum *xd;
+       struct jffs2_xattr_ref *ref, *_ref;
+
+       down_write(&c->xattr_sem);
+       for (ref = ic->xref; ref; ref = _ref) {
+               _ref = ref->next;
+               xd = ref->xd;
+               if (atomic_dec_and_test(&xd->refcnt)) {
+                       unload_xattr_datum(c, xd);
+                       jffs2_free_xattr_datum(xd);
+               }
+               jffs2_free_xattr_ref(ref);
+       }
+       ic->xref = NULL;
+       up_write(&c->xattr_sem);
+}
+
+static int check_xattr_ref_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
+{
+       /* success of check_xattr_ref_inode() means taht inode (ic) dose not have
+        * duplicate name/value pairs. If duplicate name/value pair would be found,
+        * one will be removed.
+        */
+       struct jffs2_xattr_ref *ref, *cmp, **pref, **pcmp;
+       int rc = 0;
+
+       if (likely(ic->flags & INO_FLAGS_XATTR_CHECKED))
+               return 0;
+       down_write(&c->xattr_sem);
+ retry:
+       rc = 0;
+       for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
+               if (!ref->xd->xname) {
+                       rc = load_xattr_datum(c, ref->xd);
+                       if (unlikely(rc > 0)) {
+                               *pref = ref->next;
+                               delete_xattr_ref(c, ref);
+                               goto retry;
+                       } else if (unlikely(rc < 0))
+                               goto out;
+               }
+               for (cmp=ref->next, pcmp=&ref->next; cmp; pcmp=&cmp->next, cmp=cmp->next) {
+                       if (!cmp->xd->xname) {
+                               ref->xd->flags |= JFFS2_XFLAGS_BIND;
+                               rc = load_xattr_datum(c, cmp->xd);
+                               ref->xd->flags &= ~JFFS2_XFLAGS_BIND;
+                               if (unlikely(rc > 0)) {
+                                       *pcmp = cmp->next;
+                                       delete_xattr_ref(c, cmp);
+                                       goto retry;
+                               } else if (unlikely(rc < 0))
+                                       goto out;
+                       }
+                       if (ref->xd->xprefix == cmp->xd->xprefix
+                           && !strcmp(ref->xd->xname, cmp->xd->xname)) {
+                               if (ref->xseqno > cmp->xseqno) {
+                                       *pcmp = cmp->next;
+                                       delete_xattr_ref(c, cmp);
+                               } else {
+                                       *pref = ref->next;
+                                       delete_xattr_ref(c, ref);
+                               }
+                               goto retry;
+                       }
+               }
+       }
+       ic->flags |= INO_FLAGS_XATTR_CHECKED;
+ out:
+       up_write(&c->xattr_sem);
+
+       return rc;
+}
+
+/* -------- xattr subsystem functions ---------------
+ * jffs2_init_xattr_subsystem(c)
+ *   is used to initialize semaphore and list_head, and some variables.
+ * jffs2_find_xattr_datum(c, xid)
+ *   is used to lookup xdatum while scanning process.
+ * jffs2_clear_xattr_subsystem(c)
+ *   is used to release any xattr related objects.
+ * jffs2_build_xattr_subsystem(c)
+ *   is used to associate xdatum and xref while super block building process.
+ * jffs2_setup_xattr_datum(c, xid, version)
+ *   is used to insert xdatum while scanning process.
+ * -------------------------------------------------- */
+void jffs2_init_xattr_subsystem(struct jffs2_sb_info *c)
+{
+       int i;
+
+       for (i=0; i < XATTRINDEX_HASHSIZE; i++)
+               INIT_LIST_HEAD(&c->xattrindex[i]);
+       INIT_LIST_HEAD(&c->xattr_unchecked);
+       INIT_LIST_HEAD(&c->xattr_dead_list);
+       c->xref_dead_list = NULL;
+       c->xref_temp = NULL;
+
+       init_rwsem(&c->xattr_sem);
+       c->highest_xid = 0;
+       c->highest_xseqno = 0;
+       c->xdatum_mem_usage = 0;
+       c->xdatum_mem_threshold = 32 * 1024;    /* Default 32KB */
+}
+
+static struct jffs2_xattr_datum *jffs2_find_xattr_datum(struct jffs2_sb_info *c, uint32_t xid)
+{
+       struct jffs2_xattr_datum *xd;
+       int i = xid % XATTRINDEX_HASHSIZE;
+
+       /* It's only used in scanning/building process. */
+       BUG_ON(!(c->flags & (JFFS2_SB_FLAG_SCANNING|JFFS2_SB_FLAG_BUILDING)));
+
+       list_for_each_entry(xd, &c->xattrindex[i], xindex) {
+               if (xd->xid==xid)
+                       return xd;
+       }
+       return NULL;
+}
+
+void jffs2_clear_xattr_subsystem(struct jffs2_sb_info *c)
+{
+       struct jffs2_xattr_datum *xd, *_xd;
+       struct jffs2_xattr_ref *ref, *_ref;
+       int i;
+
+       for (ref=c->xref_temp; ref; ref = _ref) {
+               _ref = ref->next;
+               jffs2_free_xattr_ref(ref);
+       }
+
+       for (ref=c->xref_dead_list; ref; ref = _ref) {
+               _ref = ref->next;
+               jffs2_free_xattr_ref(ref);
+       }
+
+       for (i=0; i < XATTRINDEX_HASHSIZE; i++) {
+               list_for_each_entry_safe(xd, _xd, &c->xattrindex[i], xindex) {
+                       list_del(&xd->xindex);
+                       if (xd->xname)
+                               kfree(xd->xname);
+                       jffs2_free_xattr_datum(xd);
+               }
+       }
+
+       list_for_each_entry_safe(xd, _xd, &c->xattr_dead_list, xindex) {
+               list_del(&xd->xindex);
+               jffs2_free_xattr_datum(xd);
+       }
+}
+
+#define XREF_TMPHASH_SIZE      (128)
+void jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
+{
+       struct jffs2_xattr_ref *ref, *_ref;
+       struct jffs2_xattr_ref *xref_tmphash[XREF_TMPHASH_SIZE];
+       struct jffs2_xattr_datum *xd, *_xd;
+       struct jffs2_inode_cache *ic;
+       struct jffs2_raw_node_ref *raw;
+       int i, xdatum_count = 0, xdatum_unchecked_count = 0, xref_count = 0;
+       int xdatum_orphan_count = 0, xref_orphan_count = 0, xref_dead_count = 0;
+
+       BUG_ON(!(c->flags & JFFS2_SB_FLAG_BUILDING));
+
+       /* Phase.1 : Merge same xref */
+       for (i=0; i < XREF_TMPHASH_SIZE; i++)
+               xref_tmphash[i] = NULL;
+       for (ref=c->xref_temp; ref; ref=_ref) {
+               struct jffs2_xattr_ref *tmp;
+
+               _ref = ref->next;
+               if (ref_flags(ref->node) != REF_PRISTINE) {
+                       if (verify_xattr_ref(c, ref)) {
+                               BUG_ON(ref->node->next_in_ino != (void *)ref);
+                               ref->node->next_in_ino = NULL;
+                               jffs2_mark_node_obsolete(c, ref->node);
+                               jffs2_free_xattr_ref(ref);
+                               continue;
+                       }
+               }
+
+               i = (ref->ino ^ ref->xid) % XREF_TMPHASH_SIZE;
+               for (tmp=xref_tmphash[i]; tmp; tmp=tmp->next) {
+                       if (tmp->ino == ref->ino && tmp->xid == ref->xid)
+                               break;
+               }
+               if (tmp) {
+                       raw = ref->node;
+                       if (ref->xseqno > tmp->xseqno) {
+                               tmp->xseqno = ref->xseqno;
+                               raw->next_in_ino = tmp->node;
+                               tmp->node = raw;
+                       } else {
+                               raw->next_in_ino = tmp->node->next_in_ino;
+                               tmp->node->next_in_ino = raw;
+                       }
+                       jffs2_free_xattr_ref(ref);
+                       continue;
+               } else {
+                       ref->next = xref_tmphash[i];
+                       xref_tmphash[i] = ref;
+               }
+       }
+       c->xref_temp = NULL;
+
+       /* Phase.2 : Bind xref with inode_cache and xattr_datum */
+       for (i=0; i < XREF_TMPHASH_SIZE; i++) {
+               for (ref=xref_tmphash[i]; ref; ref=_ref) {
+                       xref_count++;
+                       _ref = ref->next;
+                       if (is_xattr_ref_dead(ref)) {
+                               ref->next = c->xref_dead_list;
+                               c->xref_dead_list = ref;
+                               xref_dead_count++;
+                               continue;
+                       }
+                       /* At this point, ref->xid and ref->ino contain XID and inode number.
+                          ref->xd and ref->ic are not valid yet. */
+                       xd = jffs2_find_xattr_datum(c, ref->xid);
+                       ic = jffs2_get_ino_cache(c, ref->ino);
+                       if (!xd || !ic) {
+                               dbg_xattr("xref(ino=%u, xid=%u, xseqno=%u) is orphan.\n",
+                                         ref->ino, ref->xid, ref->xseqno);
+                               ref->xseqno |= XREF_DELETE_MARKER;
+                               ref->next = c->xref_dead_list;
+                               c->xref_dead_list = ref;
+                               xref_orphan_count++;
+                               continue;
+                       }
+                       ref->xd = xd;
+                       ref->ic = ic;
+                       atomic_inc(&xd->refcnt);
+                       ref->next = ic->xref;
+                       ic->xref = ref;
+               }
+       }
+
+       /* Phase.3 : Link unchecked xdatum to xattr_unchecked list */
+       for (i=0; i < XATTRINDEX_HASHSIZE; i++) {
+               list_for_each_entry_safe(xd, _xd, &c->xattrindex[i], xindex) {
+                       xdatum_count++;
+                       list_del_init(&xd->xindex);
+                       if (!atomic_read(&xd->refcnt)) {
+                               dbg_xattr("xdatum(xid=%u, version=%u) is orphan.\n",
+                                         xd->xid, xd->version);
+                               xd->flags |= JFFS2_XFLAGS_DEAD;
+                               list_add(&xd->xindex, &c->xattr_unchecked);
+                               xdatum_orphan_count++;
+                               continue;
+                       }
+                       if (is_xattr_datum_unchecked(c, xd)) {
+                               dbg_xattr("unchecked xdatum(xid=%u, version=%u)\n",
+                                         xd->xid, xd->version);
+                               list_add(&xd->xindex, &c->xattr_unchecked);
+                               xdatum_unchecked_count++;
+                       }
+               }
+       }
+       /* build complete */
+       JFFS2_NOTICE("complete building xattr subsystem, %u of xdatum"
+                    " (%u unchecked, %u orphan) and "
+                    "%u of xref (%u dead, %u orphan) found.\n",
+                    xdatum_count, xdatum_unchecked_count, xdatum_orphan_count,
+                    xref_count, xref_dead_count, xref_orphan_count);
+}
+
+struct jffs2_xattr_datum *jffs2_setup_xattr_datum(struct jffs2_sb_info *c,
+                                                 uint32_t xid, uint32_t version)
+{
+       struct jffs2_xattr_datum *xd;
+
+       xd = jffs2_find_xattr_datum(c, xid);
+       if (!xd) {
+               xd = jffs2_alloc_xattr_datum();
+               if (!xd)
+                       return ERR_PTR(-ENOMEM);
+               xd->xid = xid;
+               xd->version = version;
+               if (xd->xid > c->highest_xid)
+                       c->highest_xid = xd->xid;
+               list_add_tail(&xd->xindex, &c->xattrindex[xid % XATTRINDEX_HASHSIZE]);
+       }
+       return xd;
+}
+
+/* -------- xattr subsystem functions ---------------
+ * xprefix_to_handler(xprefix)
+ *   is used to translate xprefix into xattr_handler.
+ * jffs2_listxattr(dentry, buffer, size)
+ *   is an implementation of listxattr handler on jffs2.
+ * do_jffs2_getxattr(inode, xprefix, xname, buffer, size)
+ *   is an implementation of getxattr handler on jffs2.
+ * do_jffs2_setxattr(inode, xprefix, xname, buffer, size, flags)
+ *   is an implementation of setxattr handler on jffs2.
+ * -------------------------------------------------- */
+struct xattr_handler *jffs2_xattr_handlers[] = {
+       &jffs2_user_xattr_handler,
+#ifdef CONFIG_JFFS2_FS_SECURITY
+       &jffs2_security_xattr_handler,
+#endif
+#ifdef CONFIG_JFFS2_FS_POSIX_ACL
+       &jffs2_acl_access_xattr_handler,
+       &jffs2_acl_default_xattr_handler,
+#endif
+       &jffs2_trusted_xattr_handler,
+       NULL
+};
+
+static struct xattr_handler *xprefix_to_handler(int xprefix) {
+       struct xattr_handler *ret;
+
+       switch (xprefix) {
+       case JFFS2_XPREFIX_USER:
+               ret = &jffs2_user_xattr_handler;
+               break;
+#ifdef CONFIG_JFFS2_FS_SECURITY
+       case JFFS2_XPREFIX_SECURITY:
+               ret = &jffs2_security_xattr_handler;
+               break;
+#endif
+#ifdef CONFIG_JFFS2_FS_POSIX_ACL
+       case JFFS2_XPREFIX_ACL_ACCESS:
+               ret = &jffs2_acl_access_xattr_handler;
+               break;
+       case JFFS2_XPREFIX_ACL_DEFAULT:
+               ret = &jffs2_acl_default_xattr_handler;
+               break;
+#endif
+       case JFFS2_XPREFIX_TRUSTED:
+               ret = &jffs2_trusted_xattr_handler;
+               break;
+       default:
+               ret = NULL;
+               break;
+       }
+       return ret;
+}
+
+ssize_t jffs2_listxattr(struct dentry *dentry, char *buffer, size_t size)
+{
+       struct inode *inode = dentry->d_inode;
+       struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
+       struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
+       struct jffs2_inode_cache *ic = f->inocache;
+       struct jffs2_xattr_ref *ref, **pref;
+       struct jffs2_xattr_datum *xd;
+       struct xattr_handler *xhandle;
+       ssize_t len, rc;
+       int retry = 0;
+
+       rc = check_xattr_ref_inode(c, ic);
+       if (unlikely(rc))
+               return rc;
+
+       down_read(&c->xattr_sem);
+ retry:
+       len = 0;
+       for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
+               BUG_ON(ref->ic != ic);
+               xd = ref->xd;
+               if (!xd->xname) {
+                       /* xdatum is unchached */
+                       if (!retry) {
+                               retry = 1;
+                               up_read(&c->xattr_sem);
+                               down_write(&c->xattr_sem);
+                               goto retry;
+                       } else {
+                               rc = load_xattr_datum(c, xd);
+                               if (unlikely(rc > 0)) {
+                                       *pref = ref->next;
+                                       delete_xattr_ref(c, ref);
+                                       goto retry;
+                               } else if (unlikely(rc < 0))
+                                       goto out;
+                       }
+               }
+               xhandle = xprefix_to_handler(xd->xprefix);
+               if (!xhandle)
+                       continue;
+               if (buffer) {
+                       rc = xhandle->list(inode, buffer+len, size-len, xd->xname, xd->name_len);
+               } else {
+                       rc = xhandle->list(inode, NULL, 0, xd->xname, xd->name_len);
+               }
+               if (rc < 0)
+                       goto out;
+               len += rc;
+       }
+       rc = len;
+ out:
+       if (!retry) {
+               up_read(&c->xattr_sem);
+       } else {
+               up_write(&c->xattr_sem);
+       }
+       return rc;
+}
+
+int do_jffs2_getxattr(struct inode *inode, int xprefix, const char *xname,
+                     char *buffer, size_t size)
+{
+       struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
+       struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
+       struct jffs2_inode_cache *ic = f->inocache;
+       struct jffs2_xattr_datum *xd;
+       struct jffs2_xattr_ref *ref, **pref;
+       int rc, retry = 0;
+
+       rc = check_xattr_ref_inode(c, ic);
+       if (unlikely(rc))
+               return rc;
+
+       down_read(&c->xattr_sem);
+ retry:
+       for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
+               BUG_ON(ref->ic!=ic);
+
+               xd = ref->xd;
+               if (xd->xprefix != xprefix)
+                       continue;
+               if (!xd->xname) {
+                       /* xdatum is unchached */
+                       if (!retry) {
+                               retry = 1;
+                               up_read(&c->xattr_sem);
+                               down_write(&c->xattr_sem);
+                               goto retry;
+                       } else {
+                               rc = load_xattr_datum(c, xd);
+                               if (unlikely(rc > 0)) {
+                                       *pref = ref->next;
+                                       delete_xattr_ref(c, ref);
+                                       goto retry;
+                               } else if (unlikely(rc < 0)) {
+                                       goto out;
+                               }
+                       }
+               }
+               if (!strcmp(xname, xd->xname)) {
+                       rc = xd->value_len;
+                       if (buffer) {
+                               if (size < rc) {
+                                       rc = -ERANGE;
+                               } else {
+                                       memcpy(buffer, xd->xvalue, rc);
+                               }
+                       }
+                       goto out;
+               }
+       }
+       rc = -ENODATA;
+ out:
+       if (!retry) {
+               up_read(&c->xattr_sem);
+       } else {
+               up_write(&c->xattr_sem);
+       }
+       return rc;
+}
+
+int do_jffs2_setxattr(struct inode *inode, int xprefix, const char *xname,
+                     const char *buffer, size_t size, int flags)
+{
+       struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
+       struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
+       struct jffs2_inode_cache *ic = f->inocache;
+       struct jffs2_xattr_datum *xd;
+       struct jffs2_xattr_ref *ref, *newref, **pref;
+       uint32_t length, request;
+       int rc;
+
+       rc = check_xattr_ref_inode(c, ic);
+       if (unlikely(rc))
+               return rc;
+
+       request = PAD(sizeof(struct jffs2_raw_xattr) + strlen(xname) + 1 + size);
+       rc = jffs2_reserve_space(c, request, &length,
+                                ALLOC_NORMAL, JFFS2_SUMMARY_XATTR_SIZE);
+       if (rc) {
+               JFFS2_WARNING("jffs2_reserve_space()=%d, request=%u\n", rc, request);
+               return rc;
+       }
+
+       /* Find existing xattr */
+       down_write(&c->xattr_sem);
+ retry:
+       for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) {
+               xd = ref->xd;
+               if (xd->xprefix != xprefix)
+                       continue;
+               if (!xd->xname) {
+                       rc = load_xattr_datum(c, xd);
+                       if (unlikely(rc > 0)) {
+                               *pref = ref->next;
+                               delete_xattr_ref(c, ref);
+                               goto retry;
+                       } else if (unlikely(rc < 0))
+                               goto out;
+               }
+               if (!strcmp(xd->xname, xname)) {
+                       if (flags & XATTR_CREATE) {
+                               rc = -EEXIST;
+                               goto out;
+                       }
+                       if (!buffer) {
+                               ref->ino = ic->ino;
+                               ref->xid = xd->xid;
+                               ref->xseqno |= XREF_DELETE_MARKER;
+                               rc = save_xattr_ref(c, ref);
+                               if (!rc) {
+                                       *pref = ref->next;
+                                       spin_lock(&c->erase_completion_lock);
+                                       ref->next = c->xref_dead_list;
+                                       c->xref_dead_list = ref;
+                                       spin_unlock(&c->erase_completion_lock);
+                                       unrefer_xattr_datum(c, xd);
+                               } else {
+                                       ref->ic = ic;
+                                       ref->xd = xd;
+                                       ref->xseqno &= ~XREF_DELETE_MARKER;
+                               }
+                               goto out;
+                       }
+                       goto found;
+               }
+       }
+       /* not found */
+       if (flags & XATTR_REPLACE) {
+               rc = -ENODATA;
+               goto out;
+       }
+       if (!buffer) {
+               rc = -ENODATA;
+               goto out;
+       }
+ found:
+       xd = create_xattr_datum(c, xprefix, xname, buffer, size);
+       if (IS_ERR(xd)) {
+               rc = PTR_ERR(xd);
+               goto out;
+       }
+       up_write(&c->xattr_sem);
+       jffs2_complete_reservation(c);
+
+       /* create xattr_ref */
+       request = PAD(sizeof(struct jffs2_raw_xref));
+       rc = jffs2_reserve_space(c, request, &length,
+                                ALLOC_NORMAL, JFFS2_SUMMARY_XREF_SIZE);
+       down_write(&c->xattr_sem);
+       if (rc) {
+               JFFS2_WARNING("jffs2_reserve_space()=%d, request=%u\n", rc, request);
+               unrefer_xattr_datum(c, xd);
+               up_write(&c->xattr_sem);
+               return rc;
+       }
+       if (ref)
+               *pref = ref->next;
+       newref = create_xattr_ref(c, ic, xd);
+       if (IS_ERR(newref)) {
+               if (ref) {
+                       ref->next = ic->xref;
+                       ic->xref = ref;
+               }
+               rc = PTR_ERR(newref);
+               unrefer_xattr_datum(c, xd);
+       } else if (ref) {
+               delete_xattr_ref(c, ref);
+       }
+ out:
+       up_write(&c->xattr_sem);
+       jffs2_complete_reservation(c);
+       return rc;
+}
+
+/* -------- garbage collector functions -------------
+ * jffs2_garbage_collect_xattr_datum(c, xd, raw)
+ *   is used to move xdatum into new node.
+ * jffs2_garbage_collect_xattr_ref(c, ref, raw)
+ *   is used to move xref into new node.
+ * jffs2_verify_xattr(c)
+ *   is used to call do_verify_xattr_datum() before garbage collecting.
+ * jffs2_release_xattr_datum(c, xd)
+ *   is used to release an in-memory object of xdatum.
+ * jffs2_release_xattr_ref(c, ref)
+ *   is used to release an in-memory object of xref.
+ * -------------------------------------------------- */
+int jffs2_garbage_collect_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd,
+                                     struct jffs2_raw_node_ref *raw)
+{
+       uint32_t totlen, length, old_ofs;
+       int rc = 0;
+
+       down_write(&c->xattr_sem);
+       if (xd->node != raw)
+               goto out;
+       if (xd->flags & (JFFS2_XFLAGS_DEAD|JFFS2_XFLAGS_INVALID))
+               goto out;
+
+       rc = load_xattr_datum(c, xd);
+       if (unlikely(rc)) {
+               rc = (rc > 0) ? 0 : rc;
+               goto out;
+       }
+       old_ofs = ref_offset(xd->node);
+       totlen = PAD(sizeof(struct jffs2_raw_xattr)
+                       + xd->name_len + 1 + xd->value_len);
+       rc = jffs2_reserve_space_gc(c, totlen, &length, JFFS2_SUMMARY_XATTR_SIZE);
+       if (rc) {
+               JFFS2_WARNING("jffs2_reserve_space_gc()=%d, request=%u\n", rc, totlen);
+               goto out;
+       }
+       rc = save_xattr_datum(c, xd);
+       if (!rc)
+               dbg_xattr("xdatum (xid=%u, version=%u) GC'ed from %#08x to %08x\n",
+                         xd->xid, xd->version, old_ofs, ref_offset(xd->node));
+ out:
+       if (!rc)
+               jffs2_mark_node_obsolete(c, raw);
+       up_write(&c->xattr_sem);
+       return rc;
+}
+
+int jffs2_garbage_collect_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref,
+                                   struct jffs2_raw_node_ref *raw)
+{
+       uint32_t totlen, length, old_ofs;
+       int rc = 0;
+
+       down_write(&c->xattr_sem);
+       BUG_ON(!ref->node);
+
+       if (ref->node != raw)
+               goto out;
+       if (is_xattr_ref_dead(ref) && (raw->next_in_ino == (void *)ref))
+               goto out;
+
+       old_ofs = ref_offset(ref->node);
+       totlen = ref_totlen(c, c->gcblock, ref->node);
+
+       rc = jffs2_reserve_space_gc(c, totlen, &length, JFFS2_SUMMARY_XREF_SIZE);
+       if (rc) {
+               JFFS2_WARNING("%s: jffs2_reserve_space_gc() = %d, request = %u\n",
+                             __FUNCTION__, rc, totlen);
+               rc = rc ? rc : -EBADFD;
+               goto out;
+       }
+       rc = save_xattr_ref(c, ref);
+       if (!rc)
+               dbg_xattr("xref (ino=%u, xid=%u) GC'ed from %#08x to %08x\n",
+                         ref->ic->ino, ref->xd->xid, old_ofs, ref_offset(ref->node));
+ out:
+       if (!rc)
+               jffs2_mark_node_obsolete(c, raw);
+       up_write(&c->xattr_sem);
+       return rc;
+}
+
+int jffs2_verify_xattr(struct jffs2_sb_info *c)
+{
+       struct jffs2_xattr_datum *xd, *_xd;
+       struct jffs2_eraseblock *jeb;
+       struct jffs2_raw_node_ref *raw;
+       uint32_t totlen;
+       int rc;
+
+       down_write(&c->xattr_sem);
+       list_for_each_entry_safe(xd, _xd, &c->xattr_unchecked, xindex) {
+               rc = do_verify_xattr_datum(c, xd);
+               if (rc < 0)
+                       continue;
+               list_del_init(&xd->xindex);
+               spin_lock(&c->erase_completion_lock);
+               for (raw=xd->node; raw != (void *)xd; raw=raw->next_in_ino) {
+                       if (ref_flags(raw) != REF_UNCHECKED)
+                               continue;
+                       jeb = &c->blocks[ref_offset(raw) / c->sector_size];
+                       totlen = PAD(ref_totlen(c, jeb, raw));
+                       c->unchecked_size -= totlen; c->used_size += totlen;
+                       jeb->unchecked_size -= totlen; jeb->used_size += totlen;
+                       raw->flash_offset = ref_offset(raw)
+                               | ((xd->node == (void *)raw) ? REF_PRISTINE : REF_NORMAL);
+               }
+               if (xd->flags & JFFS2_XFLAGS_DEAD)
+                       list_add(&xd->xindex, &c->xattr_dead_list);
+               spin_unlock(&c->erase_completion_lock);
+       }
+       up_write(&c->xattr_sem);
+       return list_empty(&c->xattr_unchecked) ? 1 : 0;
+}
+
+void jffs2_release_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd)
+{
+       /* must be called under spin_lock(&c->erase_completion_lock) */
+       if (atomic_read(&xd->refcnt) || xd->node != (void *)xd)
+               return;
+
+       list_del(&xd->xindex);
+       jffs2_free_xattr_datum(xd);
+}
+
+void jffs2_release_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref)
+{
+       /* must be called under spin_lock(&c->erase_completion_lock) */
+       struct jffs2_xattr_ref *tmp, **ptmp;
+
+       if (ref->node != (void *)ref)
+               return;
+
+       for (tmp=c->xref_dead_list, ptmp=&c->xref_dead_list; tmp; ptmp=&tmp->next, tmp=tmp->next) {
+               if (ref == tmp) {
+                       *ptmp = tmp->next;
+                       break;
+               }
+       }
+       jffs2_free_xattr_ref(ref);
+}