Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1353 insertions, 0 deletions

diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
new file mode 100644
index 000000000..6b4f68593
--- /dev/null
+++ b/fs/jffs2/xattr.c
@@ -0,0 +1,1353 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2006  NEC Corporation
+ *
+ * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define JFFS2_XATTR_IS_CORRUPTED	1
+
+#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/posix_acl_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. Currently, 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", __func__, 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 JFFS2_XATTR_IS_CORRUPTED;
+	}
+	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 JFFS2_XATTR_IS_CORRUPTED;
+	}
+	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 verifying 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_XATTR)"
+			      " 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 JFFS2_XATTR_IS_CORRUPTED;
+	}
+
+	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 JFFS2_XATTR_IS_CORRUPTED;
+	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)) {
+		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",
+			  xd->xid, xd->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.
+ * jffs2_xattr_do_crccheck_inode(c, ic)
+ *   is used to force xattr data integrity check during the initial gc scan.
+ * -------------------------------------------------- */
+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 JFFS2_XATTR_IS_CORRUPTED;
+	}
+	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 JFFS2_XATTR_IS_CORRUPTED;
+	}
+	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_evict_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->pino_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 that 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;
+}
+
+void jffs2_xattr_do_crccheck_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
+{
+	check_xattr_ref_inode(c, ic);
+}
+
+/* -------- 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);
+			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);
+	}
+	list_for_each_entry_safe(xd, _xd, &c->xattr_unchecked, xindex) {
+		list_del(&xd->xindex);
+		jffs2_free_xattr_datum(xd);
+	}
+}
+
+#define XREF_TMPHASH_SIZE	(128)
+int jffs2_build_xattr_subsystem(struct jffs2_sb_info *c)
+{
+	struct jffs2_xattr_ref *ref, *_ref;
+	struct jffs2_xattr_ref **xref_tmphash;
+	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));
+
+	xref_tmphash = kzalloc_objs(struct jffs2_xattr_ref *, XREF_TMPHASH_SIZE);
+	if (!xref_tmphash)
+		return -ENOMEM;
+
+	/* Phase.1 : Merge same xref */
+	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 || !ic->pino_nlink) {
+				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);
+	kfree(xref_tmphash);
+	return 0;
+}
+
+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.
+ * -------------------------------------------------- */
+const struct xattr_handler * const jffs2_xattr_handlers[] = {
+	&jffs2_user_xattr_handler,
+#ifdef CONFIG_JFFS2_FS_SECURITY
+	&jffs2_security_xattr_handler,
+#endif
+	&jffs2_trusted_xattr_handler,
+	NULL
+};
+
+static const char *jffs2_xattr_prefix(int xprefix, struct dentry *dentry)
+{
+	const struct xattr_handler *ret = NULL;
+
+	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 = &nop_posix_acl_access;
+		break;
+	case JFFS2_XPREFIX_ACL_DEFAULT:
+		ret = &nop_posix_acl_default;
+		break;
+#endif
+	case JFFS2_XPREFIX_TRUSTED:
+		ret = &jffs2_trusted_xattr_handler;
+		break;
+	default:
+		return NULL;
+	}
+
+	if (!xattr_handler_can_list(ret, dentry))
+		return NULL;
+
+	return xattr_prefix(ret);
+}
+
+ssize_t jffs2_listxattr(struct dentry *dentry, char *buffer, size_t size)
+{
+	struct inode *inode = d_inode(dentry);
+	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;
+	const char *prefix;
+	ssize_t prefix_len, 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;
+			}
+		}
+
+		prefix = jffs2_xattr_prefix(xd->xprefix, dentry);
+		if (!prefix)
+			continue;
+		prefix_len = strlen(prefix);
+		rc = prefix_len + xd->name_len + 1;
+
+		if (buffer) {
+			if (rc > size - len) {
+				rc = -ERANGE;
+				goto out;
+			}
+			memcpy(buffer, prefix, prefix_len);
+			buffer += prefix_len;
+			memcpy(buffer, xd->xname, xd->name_len);
+			buffer += xd->name_len;
+			*buffer++ = 0;
+		}
+		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);
+	if (request > c->sector_size - c->cleanmarker_size)
+		return -ERANGE;
+
+	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",
+			      __func__, rc, totlen);
+		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);
+}