[JFFS2][XATTR] using 'delete marker' for xdatum/xref deletion

- When xdatum is removed, a new xdatum with 'delete marker' is
  written. (version==0xffffffff means 'delete marker')
- When xref is removed, a new xref with 'delete marker' is written.
  (odd-numbered xseqno means 'delete marker')

- delete_xattr_(datum/xref)_delay() are new deletion functions
  are added. We can only use them if we can detect the target
  obsolete xdatum/xref as a orphan or errir one.
  (e.g when inode deletion, or detecting crc error)

[1/3] jffs2-xattr-v6-01-delete_marker.patch
Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

fs/jffs2/erase.c

@@ -230,7 +230,6 @@ static inline void jffs2_remove_node_refs_from_ino_list(struct jffs2_sb_info *c,
 			   at the end of the linked list. Stash it and continue
 			   from the beginning of the list */
 			ic = (struct jffs2_inode_cache *)(*prev);
-			BUG_ON(ic->class != RAWNODE_CLASS_INODE_CACHE);
 			prev = &ic->nodes;
 			continue;
 		}
@@ -254,7 +253,8 @@ static inline void jffs2_remove_node_refs_from_ino_list(struct jffs2_sb_info *c,
 
 	/* PARANOIA */
 	if (!ic) {
-		printk(KERN_WARNING "inode_cache not found in remove_node_refs()!!\n");
+		JFFS2_WARNING("inode_cache/xattr_datum/xattr_ref"
+			      " not found in remove_node_refs()!!\n");
 		return;
 	}
 
@@ -279,8 +279,19 @@ static inline void jffs2_remove_node_refs_from_ino_list(struct jffs2_sb_info *c,
 		printk("\n");
 	});
 
-	if (ic->nodes == (void *)ic && ic->nlink == 0)
-		jffs2_del_ino_cache(c, ic);
+	switch (ic->class) {
+#ifdef CONFIG_JFFS2_FS_XATTR
+		case RAWNODE_CLASS_XATTR_DATUM:
+			jffs2_release_xattr_datum(c, (struct jffs2_xattr_datum *)ic);
+			break;
+		case RAWNODE_CLASS_XATTR_REF:
+			jffs2_release_xattr_ref(c, (struct jffs2_xattr_ref *)ic);
+			break;
+#endif
+		default:
+			if (ic->nodes == (void *)ic && ic->nlink == 0)
+				jffs2_del_ino_cache(c, ic);
+	}
 }
 
 void jffs2_free_jeb_node_refs(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)

fs/jffs2/gc.c

@@ -275,13 +275,12 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
 	 * We can decide whether this node is inode or xattr by ic->class.     */
 	if (ic->class == RAWNODE_CLASS_XATTR_DATUM
 	    || ic->class == RAWNODE_CLASS_XATTR_REF) {
-		BUG_ON(raw->next_in_ino != (void *)ic);
 		spin_unlock(&c->erase_completion_lock);
 
 		if (ic->class == RAWNODE_CLASS_XATTR_DATUM) {
-			ret = jffs2_garbage_collect_xattr_datum(c, (struct jffs2_xattr_datum *)ic);
+			ret = jffs2_garbage_collect_xattr_datum(c, (struct jffs2_xattr_datum *)ic, raw);
 		} else {
-			ret = jffs2_garbage_collect_xattr_ref(c, (struct jffs2_xattr_ref *)ic);
+			ret = jffs2_garbage_collect_xattr_ref(c, (struct jffs2_xattr_ref *)ic, raw);
 		}
 		goto release_sem;
 	}

fs/jffs2/jffs2_fs_sb.h

@@ -119,8 +119,11 @@ struct jffs2_sb_info {
 #ifdef CONFIG_JFFS2_FS_XATTR
 #define XATTRINDEX_HASHSIZE	(57)
 	uint32_t highest_xid;
+	uint32_t highest_xseqno;
 	struct list_head xattrindex[XATTRINDEX_HASHSIZE];
 	struct list_head xattr_unchecked;
+	struct list_head xattr_dead_list;
+	struct jffs2_xattr_ref *xref_dead_list;
 	struct jffs2_xattr_ref *xref_temp;
 	struct rw_semaphore xattr_sem;
 	uint32_t xdatum_mem_usage;

fs/jffs2/malloc.c

@@ -291,6 +291,7 @@ struct jffs2_xattr_datum *jffs2_alloc_xattr_datum(void)
 
 	memset(xd, 0, sizeof(struct jffs2_xattr_datum));
 	xd->class = RAWNODE_CLASS_XATTR_DATUM;
+	xd->node = (void *)xd;
 	INIT_LIST_HEAD(&xd->xindex);
 	return xd;
 }
@@ -309,6 +310,7 @@ struct jffs2_xattr_ref *jffs2_alloc_xattr_ref(void)
 
 	memset(ref, 0, sizeof(struct jffs2_xattr_ref));
 	ref->class = RAWNODE_CLASS_XATTR_REF;
+	ref->node = (void *)ref;
 	return ref;
 }
 

fs/jffs2/nodemgmt.c

@@ -684,19 +684,26 @@ void jffs2_mark_node_obsolete(struct jffs2_sb_info *c, struct jffs2_raw_node_ref
 		spin_lock(&c->erase_completion_lock);
 
 		ic = jffs2_raw_ref_to_ic(ref);
-		/* It seems we should never call jffs2_mark_node_obsolete() for
-		   XATTR nodes.... yet. Make sure we notice if/when we change
-		   that :) */
-		BUG_ON(ic->class != RAWNODE_CLASS_INODE_CACHE);
 		for (p = &ic->nodes; (*p) != ref; p = &((*p)->next_in_ino))
 			;
 
 		*p = ref->next_in_ino;
 		ref->next_in_ino = NULL;
 
-		if (ic->nodes == (void *)ic && ic->nlink == 0)
-			jffs2_del_ino_cache(c, ic);
-
+		switch (ic->class) {
+#ifdef CONFIG_JFFS2_FS_XATTR
+			case RAWNODE_CLASS_XATTR_DATUM:
+				jffs2_release_xattr_datum(c, (struct jffs2_xattr_datum *)ic);
+				break;
+			case RAWNODE_CLASS_XATTR_REF:
+				jffs2_release_xattr_ref(c, (struct jffs2_xattr_ref *)ic);
+				break;
+#endif
+			default:
+				if (ic->nodes == (void *)ic && ic->nlink == 0)
+					jffs2_del_ino_cache(c, ic);
+				break;
+		}
 		spin_unlock(&c->erase_completion_lock);
 	}
 

fs/jffs2/scan.c

@@ -317,20 +317,25 @@ static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_erasebloc
 				 struct jffs2_summary *s)
 {
 	struct jffs2_xattr_datum *xd;
-	uint32_t totlen, crc;
+	uint32_t xid, version, totlen, crc;
 	int err;
 
 	crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
 	if (crc != je32_to_cpu(rx->node_crc)) {
-		if (je32_to_cpu(rx->node_crc) != 0xffffffff)
-			JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
-				      ofs, je32_to_cpu(rx->node_crc), crc);
+		JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
+			      ofs, je32_to_cpu(rx->node_crc), crc);
 		if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
 			return err;
 		return 0;
 	}
 
-	totlen = PAD(sizeof(*rx) + rx->name_len + 1 + je16_to_cpu(rx->value_len));
+	xid = je32_to_cpu(rx->xid);
+	version = je32_to_cpu(rx->version);
+
+	totlen = sizeof(struct jffs2_raw_xattr);
+	if (version != XDATUM_DELETE_MARKER)
+		totlen += rx->name_len + 1 + je16_to_cpu(rx->value_len);
+	totlen = PAD(totlen);
 	if (totlen != je32_to_cpu(rx->totlen)) {
 		JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
 			      ofs, je32_to_cpu(rx->totlen), totlen);
@@ -339,22 +344,24 @@ static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_erasebloc
 		return 0;
 	}
 
-	xd = jffs2_setup_xattr_datum(c, je32_to_cpu(rx->xid), je32_to_cpu(rx->version));
-	if (IS_ERR(xd)) {
-		if (PTR_ERR(xd) == -EEXIST) {
-			if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rx->totlen)))))
-				return err;
-			return 0;
-		}
+	xd = jffs2_setup_xattr_datum(c, xid, version);
+	if (IS_ERR(xd))
 		return PTR_ERR(xd);
-	}
-	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);
 
-	xd->node = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
-	/* FIXME */ xd->node->next_in_ino = (void *)xd;
+	if (xd->version > version) {
+		struct jffs2_raw_node_ref *raw
+			= jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
+		raw->next_in_ino = xd->node->next_in_ino;
+		xd->node->next_in_ino = raw;
+	} else {
+		xd->version = version;
+		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);
+
+		jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
+	}
 
 	if (jffs2_sum_active())
 		jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
@@ -373,9 +380,8 @@ static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock
 
 	crc = crc32(0, rr, sizeof(*rr) - 4);
 	if (crc != je32_to_cpu(rr->node_crc)) {
-		if (je32_to_cpu(rr->node_crc) != 0xffffffff)
-			JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
-				      ofs, je32_to_cpu(rr->node_crc), crc);
+		JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
+			      ofs, je32_to_cpu(rr->node_crc), crc);
 		if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
 			return err;
 		return 0;
@@ -395,6 +401,7 @@ static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock
 		return -ENOMEM;
 
 	/* BEFORE jffs2_build_xattr_subsystem() called, 
+	 * and AFTER xattr_ref is marked as a dead xref,
 	 * ref->xid is used to store 32bit xid, xd is not used
 	 * ref->ino is used to store 32bit inode-number, ic is not used
 	 * Thoes variables are declared as union, thus using those
@@ -404,11 +411,13 @@ static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock
 	 */
 	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);
 	ref->next = c->xref_temp;
 	c->xref_temp = ref;
 
-	ref->node = jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), NULL);
-	/* FIXME */ ref->node->next_in_ino = (void *)ref;
+	jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);
 
 	if (jffs2_sum_active())
 		jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);

fs/jffs2/summary.c

@@ -310,8 +310,6 @@ int jffs2_sum_add_kvec(struct jffs2_sb_info *c, const struct kvec *invecs,
 #ifdef CONFIG_JFFS2_FS_XATTR
 		case JFFS2_NODETYPE_XATTR: {
 			struct jffs2_sum_xattr_mem *temp;
-			if (je32_to_cpu(node->x.version) == 0xffffffff)
-				return 0;
 			temp = kmalloc(sizeof(struct jffs2_sum_xattr_mem), GFP_KERNEL);
 			if (!temp)
 				goto no_mem;
@@ -327,10 +325,6 @@ int jffs2_sum_add_kvec(struct jffs2_sb_info *c, const struct kvec *invecs,
 		}
 		case JFFS2_NODETYPE_XREF: {
 			struct jffs2_sum_xref_mem *temp;
-
-			if (je32_to_cpu(node->r.ino) == 0xffffffff
-			    && je32_to_cpu(node->r.xid) == 0xffffffff)
-				return 0;
 			temp = kmalloc(sizeof(struct jffs2_sum_xref_mem), GFP_KERNEL);
 			if (!temp)
 				goto no_mem;
@@ -483,22 +477,20 @@ static int jffs2_sum_process_sum_data(struct jffs2_sb_info *c, struct jffs2_eras
 
 				xd = jffs2_setup_xattr_datum(c, je32_to_cpu(spx->xid),
 								je32_to_cpu(spx->version));
-				if (IS_ERR(xd)) {
-					if (PTR_ERR(xd) == -EEXIST) {
-						/* a newer version of xd exists */
-						if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(spx->totlen))))
-							return err;
-						sp += JFFS2_SUMMARY_XATTR_SIZE;
-						break;
-					}
-					JFFS2_NOTICE("allocation of xattr_datum failed\n");
+				if (IS_ERR(xd))
 					return PTR_ERR(xd);
+				if (xd->version > je32_to_cpu(spx->version)) {
+					/* node is not the newest one */
+					struct jffs2_raw_node_ref *raw
+						= sum_link_node_ref(c, jeb, je32_to_cpu(spx->offset) | REF_UNCHECKED,
+								    PAD(je32_to_cpu(spx->totlen)), NULL);
+					raw->next_in_ino = xd->node->next_in_ino;
+					xd->node->next_in_ino = raw;
+				} else {
+					xd->version = je32_to_cpu(spx->version);
+					sum_link_node_ref(c, jeb, je32_to_cpu(spx->offset) | REF_UNCHECKED,
+							  PAD(je32_to_cpu(spx->totlen)), (void *)xd);
 				}
-
-				xd->node = sum_link_node_ref(c, jeb, je32_to_cpu(spx->offset) | REF_UNCHECKED,
-							     PAD(je32_to_cpu(spx->totlen)), NULL);
-				/* FIXME */ xd->node->next_in_ino = (void *)xd;
-
 				*pseudo_random += je32_to_cpu(spx->xid);
 				sp += JFFS2_SUMMARY_XATTR_SIZE;
 
@@ -519,14 +511,11 @@ static int jffs2_sum_process_sum_data(struct jffs2_sb_info *c, struct jffs2_eras
 					JFFS2_NOTICE("allocation of xattr_datum failed\n");
 					return -ENOMEM;
 				}
-				ref->ino = 0xfffffffe;
-				ref->xid = 0xfffffffd;
 				ref->next = c->xref_temp;
 				c->xref_temp = ref;
 
-				ref->node = sum_link_node_ref(c, jeb, je32_to_cpu(spr->offset) | REF_UNCHECKED,
-							      PAD(sizeof(struct jffs2_raw_xref)), NULL);
-				/* FIXME */ ref->node->next_in_ino = (void *)ref;
+				sum_link_node_ref(c, jeb, je32_to_cpu(spr->offset) | REF_UNCHECKED,
+						  PAD(sizeof(struct jffs2_raw_xref)), (void *)ref);
 
 				*pseudo_random += ref->node->flash_offset;
 				sp += JFFS2_SUMMARY_XREF_SIZE;

fs/jffs2/xattr.h

@@ -16,6 +16,7 @@
 
 #define JFFS2_XFLAGS_HOT	(0x01)	/* This datum is HOT */
 #define JFFS2_XFLAGS_BIND	(0x02)	/* This datum is not reclaimed */
+#define JFFS2_XFLAGS_INVALID	(0x80)	/* This datum contains crc error */
 
 struct jffs2_xattr_datum
 {
@@ -23,7 +24,7 @@ struct jffs2_xattr_datum
 	struct jffs2_raw_node_ref *node;
 	uint8_t class;
 	uint8_t flags;
-	uint16_t xprefix;			/* see JFFS2_XATTR_PREFIX_* */
+	uint16_t xprefix;		/* see JFFS2_XATTR_PREFIX_* */
 
 	struct list_head xindex;	/* chained from c->xattrindex[n] */
 	uint32_t refcnt;		/* # of xattr_ref refers this */
@@ -47,6 +48,7 @@ struct jffs2_xattr_ref
 	uint8_t flags;		/* Currently unused */
 	u16 unused;
 
+	uint32_t xseqno;
 	union {
 		struct jffs2_inode_cache *ic;	/* reference to jffs2_inode_cache */
 		uint32_t ino;			/* only used in scanning/building  */
@@ -58,6 +60,34 @@ struct jffs2_xattr_ref
 	struct jffs2_xattr_ref *next;		/* chained from ic->xref_list */
 };
 
+#define XDATUM_DELETE_MARKER	(0xffffffff)
+#define XREF_DELETE_MARKER	(0x00000001)
+static inline int is_xattr_datum_dead(struct jffs2_xattr_datum *xd)
+{
+	return (xd->version == XDATUM_DELETE_MARKER);
+}
+
+static inline void set_xattr_datum_dead(struct jffs2_xattr_datum *xd)
+{
+	xd->version = XDATUM_DELETE_MARKER;
+}
+
+static inline int is_xattr_ref_dead(struct jffs2_xattr_ref *ref)
+{
+	return ((ref->xseqno & XREF_DELETE_MARKER) != 0);
+}
+
+static inline void set_xattr_ref_dead(struct jffs2_xattr_ref *ref)
+{
+	ref->xseqno |= XREF_DELETE_MARKER;
+}
+
+static inline void clr_xattr_ref_dead(struct jffs2_xattr_ref *ref)
+{
+	ref->xseqno &= ~XREF_DELETE_MARKER;
+}
+
+
 #ifdef CONFIG_JFFS2_FS_XATTR
 
 extern void jffs2_init_xattr_subsystem(struct jffs2_sb_info *c);
@@ -70,9 +100,13 @@ extern struct jffs2_xattr_datum *jffs2_setup_xattr_datum(struct jffs2_sb_info *c
 extern void jffs2_xattr_delete_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic);
 extern void jffs2_xattr_free_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic);
 
-extern int jffs2_garbage_collect_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd);
-extern int jffs2_garbage_collect_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref);
+extern int jffs2_garbage_collect_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd,
+					     struct jffs2_raw_node_ref *raw);
+extern int jffs2_garbage_collect_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref,
+					   struct jffs2_raw_node_ref *raw);
 extern int jffs2_verify_xattr(struct jffs2_sb_info *c);
+extern void jffs2_release_xattr_datum(struct jffs2_sb_info *c, struct jffs2_xattr_datum *xd);
+extern void jffs2_release_xattr_ref(struct jffs2_sb_info *c, struct jffs2_xattr_ref *ref);
 
 extern int do_jffs2_getxattr(struct inode *inode, int xprefix, const char *xname,
 			     char *buffer, size_t size);

include/linux/jffs2.h

@@ -186,6 +186,7 @@ struct jffs2_raw_xref
 	jint32_t hdr_crc;
 	jint32_t ino;		/* inode number */
 	jint32_t xid;		/* XATTR identifier number */
+	jint32_t xseqno;	/* xref sequencial number */
 	jint32_t node_crc;
 } __attribute__((packed));