xattr.c

linux 内核源代码

	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);
	}
	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)
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 || !ic->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);
}

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)