Merge remote branch 'nilfs2/for-next'

12 files changed, 167 insertions, 179 deletions

diff --git a/fs/nilfs2/gcinode.c b/fs/nilfs2/gcinode.c
index bed3a783129b..34f8f84a22e3 100644
--- a/fs/nilfs2/gcinode.c
+++ b/fs/nilfs2/gcinode.c
@@ -28,13 +28,6 @@
  * gcinodes), and this file provides lookup function of the dummy
  * inodes and their buffer read function.
  *
- * Since NILFS2 keeps up multiple checkpoints/snapshots across GC, it
- * has to treat blocks that belong to a same file but have different
- * checkpoint numbers.  To avoid interference among generations, dummy
- * inodes are managed separately from actual inodes, and their lookup
- * function (nilfs_gc_iget) is designed to be specified with a
- * checkpoint number argument as well as an inode number.
- *
  * Buffers and pages held by the dummy inodes will be released each
  * time after they are copied to a new log.  Dirty blocks made on the
  * current generation and the blocks to be moved by GC never overlap
@@ -180,120 +173,41 @@ int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh)
 	return 0;
 }
 
-/*
- * nilfs_init_gccache() - allocate and initialize gc_inode hash table
- * @nilfs - the_nilfs
- *
- * Return Value: On success, 0.
- * On error, a negative error code is returned.
- */
-int nilfs_init_gccache(struct the_nilfs *nilfs)
-{
-	int loop;
-
-	BUG_ON(nilfs->ns_gc_inodes_h);
-
-	INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
-
-	nilfs->ns_gc_inodes_h =
-		kmalloc(sizeof(struct hlist_head) * NILFS_GCINODE_HASH_SIZE,
-			GFP_NOFS);
-	if (nilfs->ns_gc_inodes_h == NULL)
-		return -ENOMEM;
-
-	for (loop = 0; loop < NILFS_GCINODE_HASH_SIZE; loop++)
-		INIT_HLIST_HEAD(&nilfs->ns_gc_inodes_h[loop]);
-	return 0;
-}
-
-/*
- * nilfs_destroy_gccache() - free gc_inode hash table
- * @nilfs - the nilfs
- */
-void nilfs_destroy_gccache(struct the_nilfs *nilfs)
-{
-	if (nilfs->ns_gc_inodes_h) {
-		nilfs_remove_all_gcinode(nilfs);
-		kfree(nilfs->ns_gc_inodes_h);
-		nilfs->ns_gc_inodes_h = NULL;
-	}
-}
-
-static struct inode *alloc_gcinode(struct the_nilfs *nilfs, ino_t ino,
-				   __u64 cno)
-{
-	struct inode *inode;
-	struct nilfs_inode_info *ii;
-
-	inode = nilfs_mdt_new_common(nilfs, NULL, ino, GFP_NOFS, 0);
-	if (!inode)
-		return NULL;
-
-	inode->i_op = NULL;
-	inode->i_fop = NULL;
-	inode->i_mapping->a_ops = &def_gcinode_aops;
-
-	ii = NILFS_I(inode);
-	ii->i_cno = cno;
-	ii->i_flags = 0;
-	ii->i_state = 1 << NILFS_I_GCINODE;
-	ii->i_bh = NULL;
-	nilfs_bmap_init_gc(ii->i_bmap);
-
-	return inode;
-}
-
-static unsigned long ihash(ino_t ino, __u64 cno)
+int nilfs_init_gcinode(struct inode *inode)
 {
-	return hash_long((unsigned long)((ino << 2) + cno),
-			 NILFS_GCINODE_HASH_BITS);
-}
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+	int ret;
 
-/*
- * nilfs_gc_iget() - find or create gc inode with specified (ino,cno)
- */
-struct inode *nilfs_gc_iget(struct the_nilfs *nilfs, ino_t ino, __u64 cno)
-{
-	struct hlist_head *head = nilfs->ns_gc_inodes_h + ihash(ino, cno);
-	struct hlist_node *node;
-	struct inode *inode;
+	ret = nilfs_mdt_init(inode, nilfs, GFP_NOFS, 0);
+	if (!ret) {
+		inode->i_mapping->a_ops = &def_gcinode_aops;
 
-	hlist_for_each_entry(inode, node, head, i_hash) {
-		if (inode->i_ino == ino && NILFS_I(inode)->i_cno == cno)
-			return inode;
-	}
+		ii->i_flags = 0;
+		nilfs_bmap_init_gc(ii->i_bmap);
 
-	inode = alloc_gcinode(nilfs, ino, cno);
-	if (likely(inode)) {
-		hlist_add_head(&inode->i_hash, head);
+		/*
+		 * Add the inode to GC inode list. Garbage Collection
+		 * is serialized and no two processes manipulate the
+		 * list simultaneously.
+		 */
+		igrab(inode);
 		list_add(&NILFS_I(inode)->i_dirty, &nilfs->ns_gc_inodes);
 	}
-	return inode;
-}
-
-/*
- * nilfs_clear_gcinode() - clear and free a gc inode
- */
-void nilfs_clear_gcinode(struct inode *inode)
-{
-	nilfs_mdt_destroy(inode);
+	return ret;
 }
 
-/*
- * nilfs_remove_all_gcinode() - remove all inodes from the_nilfs
+/**
+ * nilfs_remove_all_gcinodes() - remove all unprocessed gc inodes
  */
-void nilfs_remove_all_gcinode(struct the_nilfs *nilfs)
+void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs)
 {
-	struct hlist_head *head = nilfs->ns_gc_inodes_h;
-	struct hlist_node *node, *n;
-	struct inode *inode;
-	int loop;
+	struct list_head *head = &nilfs->ns_gc_inodes;
+	struct nilfs_inode_info *ii;
 
-	for (loop = 0; loop < NILFS_GCINODE_HASH_SIZE; loop++, head++) {
-		hlist_for_each_entry_safe(inode, node, n, head, i_hash) {
-			hlist_del_init(&inode->i_hash);
-			list_del_init(&NILFS_I(inode)->i_dirty);
-			nilfs_clear_gcinode(inode); /* might sleep */
-		}
+	while (!list_empty(head)) {
+		ii = list_first_entry(head, struct nilfs_inode_info, i_dirty);
+		list_del_init(&ii->i_dirty);
+		iput(&ii->vfs_inode);
 	}
 }
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index eccb2f2e2315..82cfdbc43e1c 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -34,6 +34,11 @@
 #include "cpfile.h"
 #include "ifile.h"
 
+struct nilfs_iget_args {
+	u64 ino;
+	__u64 cno;
+	int for_gc;
+};
 
 /**
  * nilfs_get_block() - get a file block on the filesystem (callback function)
@@ -320,7 +325,6 @@ struct inode *nilfs_new_inode(struct inode *dir, int mode)
 	/* ii->i_file_acl = 0; */
 	/* ii->i_dir_acl = 0; */
 	ii->i_dir_start_lookup = 0;
-	ii->i_cno = 0;
 	nilfs_set_inode_flags(inode);
 	spin_lock(&sbi->s_next_gen_lock);
 	inode->i_generation = sbi->s_next_generation++;
@@ -410,7 +414,6 @@ int nilfs_read_inode_common(struct inode *inode,
 		0 : le32_to_cpu(raw_inode->i_dir_acl);
 #endif
 	ii->i_dir_start_lookup = 0;
-	ii->i_cno = 0;
 	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
 
 	if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
@@ -476,12 +479,40 @@ static int __nilfs_read_inode(struct super_block *sb, unsigned long ino,
 	return err;
 }
 
+static int nilfs_iget_test(struct inode *inode, void *opaque)
+{
+	struct nilfs_iget_args *args = opaque;
+	struct nilfs_inode_info *ii;
+
+	if (args->ino != inode->i_ino)
+		return 0;
+
+	ii = NILFS_I(inode);
+	if (!test_bit(NILFS_I_GCINODE, &ii->i_state))
+		return !args->for_gc;
+
+	return args->for_gc && args->cno == ii->i_cno;
+}
+
+static int nilfs_iget_set(struct inode *inode, void *opaque)
+{
+	struct nilfs_iget_args *args = opaque;
+
+	inode->i_ino = args->ino;
+	if (args->for_gc) {
+		NILFS_I(inode)->i_state = 1 << NILFS_I_GCINODE;
+		NILFS_I(inode)->i_cno = args->cno;
+	}
+	return 0;
+}
+
 struct inode *nilfs_iget(struct super_block *sb, unsigned long ino)
 {
+	struct nilfs_iget_args args = { .ino = ino, .cno = 0, .for_gc = 0 };
 	struct inode *inode;
 	int err;
 
-	inode = iget_locked(sb, ino);
+	inode = iget5_locked(sb, ino, nilfs_iget_test, nilfs_iget_set, &args);
 	if (unlikely(!inode))
 		return ERR_PTR(-ENOMEM);
 	if (!(inode->i_state & I_NEW))
@@ -496,6 +527,28 @@ struct inode *nilfs_iget(struct super_block *sb, unsigned long ino)
 	return inode;
 }
 
+struct inode *nilfs_iget_for_gc(struct super_block *sb, unsigned long ino,
+				__u64 cno)
+{
+	struct nilfs_iget_args args = { .ino = ino, .cno = cno, .for_gc = 1 };
+	struct inode *inode;
+	int err;
+
+	inode = iget5_locked(sb, ino, nilfs_iget_test, nilfs_iget_set, &args);
+	if (unlikely(!inode))
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+
+	err = nilfs_init_gcinode(inode);
+	if (unlikely(err)) {
+		iget_failed(inode);
+		return ERR_PTR(err);
+	}
+	unlock_new_inode(inode);
+	return inode;
+}
+
 void nilfs_write_inode_common(struct inode *inode,
 			      struct nilfs_inode *raw_inode, int has_bmap)
 {
@@ -808,6 +861,7 @@ int nilfs_mark_inode_dirty(struct inode *inode)
 void nilfs_dirty_inode(struct inode *inode)
 {
 	struct nilfs_transaction_info ti;
+	struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
 
 	if (is_bad_inode(inode)) {
 		nilfs_warning(inode->i_sb, __func__,
@@ -815,6 +869,10 @@ void nilfs_dirty_inode(struct inode *inode)
 		dump_stack();
 		return;
 	}
+	if (mdi) {
+		nilfs_mdt_mark_dirty(inode);
+		return;
+	}
 	nilfs_transaction_begin(inode->i_sb, &ti, 0);
 	nilfs_mark_inode_dirty(inode);
 	nilfs_transaction_commit(inode->i_sb); /* never fails */
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index f90a33d9a5b0..f0a99bdb10f5 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -334,7 +334,7 @@ static int nilfs_ioctl_move_inode_block(struct inode *inode,
 	return 0;
 }
 
-static int nilfs_ioctl_move_blocks(struct the_nilfs *nilfs,
+static int nilfs_ioctl_move_blocks(struct super_block *sb,
 				   struct nilfs_argv *argv, void *buf)
 {
 	size_t nmembs = argv->v_nmembs;
@@ -349,7 +349,7 @@ static int nilfs_ioctl_move_blocks(struct the_nilfs *nilfs,
 	for (i = 0, vdesc = buf; i < nmembs; ) {
 		ino = vdesc->vd_ino;
 		cno = vdesc->vd_cno;
-		inode = nilfs_gc_iget(nilfs, ino, cno);
+		inode = nilfs_iget_for_gc(sb, ino, cno);
 		if (unlikely(inode == NULL)) {
 			ret = -ENOMEM;
 			goto failed;
@@ -357,11 +357,15 @@ static int nilfs_ioctl_move_blocks(struct the_nilfs *nilfs,
 		do {
 			ret = nilfs_ioctl_move_inode_block(inode, vdesc,
 							   &buffers);
-			if (unlikely(ret < 0))
+			if (unlikely(ret < 0)) {
+				iput(inode);
 				goto failed;
+			}
 			vdesc++;
 		} while (++i < nmembs &&
 			 vdesc->vd_ino == ino && vdesc->vd_cno == cno);
+
+		iput(inode); /* The inode still remains in GC inode list */
 	}
 
 	list_for_each_entry_safe(bh, n, &buffers, b_assoc_buffers) {
@@ -567,7 +571,7 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
 	}
 
 	/*
-	 * nilfs_ioctl_move_blocks() will call nilfs_gc_iget(),
+	 * nilfs_ioctl_move_blocks() will call nilfs_iget_for_gc(),
 	 * which will operates an inode list without blocking.
 	 * To protect the list from concurrent operations,
 	 * nilfs_ioctl_move_blocks should be atomic operation.
@@ -577,15 +581,14 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
 		goto out_free;
 	}
 
-	ret = nilfs_ioctl_move_blocks(nilfs, &argv[0], kbufs[0]);
+	ret = nilfs_ioctl_move_blocks(inode->i_sb, &argv[0], kbufs[0]);
 	if (ret < 0)
 		printk(KERN_ERR "NILFS: GC failed during preparation: "
 			"cannot read source blocks: err=%d\n", ret);
 	else
 		ret = nilfs_clean_segments(inode->i_sb, argv, kbufs);
 
-	if (ret < 0)
-		nilfs_remove_all_gcinode(nilfs);
+	nilfs_remove_all_gcinodes(nilfs);
 	clear_nilfs_gc_running(nilfs);
 
 out_free:
diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index d01aff4957d9..73e5da3b097e 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -439,6 +439,27 @@ static const struct address_space_operations def_mdt_aops = {
 static const struct inode_operations def_mdt_iops;
 static const struct file_operations def_mdt_fops;
 
+
+int nilfs_mdt_init(struct inode *inode, struct the_nilfs *nilfs,
+		   gfp_t gfp_mask, size_t objsz)
+{
+	struct nilfs_mdt_info *mi;
+
+	mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
+	if (!mi)
+		return -ENOMEM;
+
+	mi->mi_nilfs = nilfs;
+	init_rwsem(&mi->mi_sem);
+	inode->i_private = mi;
+
+	inode->i_mode = S_IFREG;
+	mapping_set_gfp_mask(inode->i_mapping, gfp_mask);
+	inode->i_mapping->backing_dev_info = nilfs->ns_bdi;
+
+	return 0;
+}
+
 /*
  * NILFS2 uses pseudo inodes for meta data files such as DAT, cpfile, sufile,
  * ifile, or gcinodes.  This allows the B-tree code and segment constructor
@@ -454,12 +475,10 @@ static const struct file_operations def_mdt_fops;
  * @nilfs: nilfs object
  * @sb: super block instance the metadata file belongs to
  * @ino: inode number
- * @gfp_mask: gfp mask for data pages
- * @objsz: size of the private object attached to inode->i_private
  */
 struct inode *
 nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
-		     ino_t ino, gfp_t gfp_mask, size_t objsz)
+		     ino_t ino)
 {
 	struct inode *inode = nilfs_alloc_inode_common(nilfs);
 
@@ -467,15 +486,6 @@ nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
 		return NULL;
 	else {
 		struct address_space * const mapping = &inode->i_data;
-		struct nilfs_mdt_info *mi;
-
-		mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
-		if (!mi) {
-			nilfs_destroy_inode(inode);
-			return NULL;
-		}
-		mi->mi_nilfs = nilfs;
-		init_rwsem(&mi->mi_sem);
 
 		inode->i_sb = sb; /* sb may be NULL for some meta data files */
 		inode->i_blkbits = nilfs->ns_blocksize_bits;
@@ -483,8 +493,6 @@ nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
 		atomic_set(&inode->i_count, 1);
 		inode->i_nlink = 1;
 		inode->i_ino = ino;
-		inode->i_mode = S_IFREG;
-		inode->i_private = mi;
 
 #ifdef INIT_UNUSED_INODE_FIELDS
 		atomic_set(&inode->i_writecount, 0);
@@ -515,9 +523,7 @@ nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
 
 		mapping->host = NULL;  /* instead of inode */
 		mapping->flags = 0;
-		mapping_set_gfp_mask(mapping, gfp_mask);
 		mapping->assoc_mapping = NULL;
-		mapping->backing_dev_info = nilfs->ns_bdi;
 
 		inode->i_mapping = mapping;
 	}
@@ -530,10 +536,14 @@ struct inode *nilfs_mdt_new(struct the_nilfs *nilfs, struct super_block *sb,
 {
 	struct inode *inode;
 
-	inode = nilfs_mdt_new_common(nilfs, sb, ino, NILFS_MDT_GFP, objsz);
+	inode = nilfs_mdt_new_common(nilfs, sb, ino);
 	if (!inode)
 		return NULL;
 
+	if (nilfs_mdt_init(inode, nilfs, NILFS_MDT_GFP, objsz) < 0) {
+		nilfs_destroy_inode(inode);
+		return NULL;
+	}
 	inode->i_op = &def_mdt_iops;
 	inode->i_fop = &def_mdt_fops;
 	inode->i_mapping->a_ops = &def_mdt_aops;
@@ -577,7 +587,5 @@ void nilfs_mdt_destroy(struct inode *inode)
 		nilfs_palloc_destroy_cache(inode);
 	nilfs_mdt_clear(inode);
 
-	kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
-	kfree(mdi);
 	nilfs_destroy_inode(inode);
 }
diff --git a/fs/nilfs2/mdt.h b/fs/nilfs2/mdt.h
index 6c4bbb0470fc..f44560224bd1 100644
--- a/fs/nilfs2/mdt.h
+++ b/fs/nilfs2/mdt.h
@@ -76,10 +76,12 @@ int nilfs_mdt_forget_block(struct inode *, unsigned long);
 int nilfs_mdt_mark_block_dirty(struct inode *, unsigned long);
 int nilfs_mdt_fetch_dirty(struct inode *);
 
+int nilfs_mdt_init(struct inode *inode, struct the_nilfs *nilfs,
+		   gfp_t gfp_mask, size_t objsz);
 struct inode *nilfs_mdt_new(struct the_nilfs *, struct super_block *, ino_t,
 			    size_t);
 struct inode *nilfs_mdt_new_common(struct the_nilfs *, struct super_block *,
-				   ino_t, gfp_t, size_t);
+				   ino_t);
 void nilfs_mdt_destroy(struct inode *);
 void nilfs_mdt_set_entry_size(struct inode *, unsigned, unsigned);
 void nilfs_mdt_set_shadow(struct inode *, struct inode *);
diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h
index d3d54046e5f8..797cd437970e 100644
--- a/fs/nilfs2/nilfs.h
+++ b/fs/nilfs2/nilfs.h
@@ -248,6 +248,8 @@ extern void nilfs_set_inode_flags(struct inode *);
 extern int nilfs_read_inode_common(struct inode *, struct nilfs_inode *);
 extern void nilfs_write_inode_common(struct inode *, struct nilfs_inode *, int);
 extern struct inode *nilfs_iget(struct super_block *, unsigned long);
+extern struct inode *nilfs_iget_for_gc(struct super_block *sb,
+				       unsigned long ino, __u64 cno);
 extern void nilfs_update_inode(struct inode *, struct buffer_head *);
 extern void nilfs_truncate(struct inode *);
 extern void nilfs_evict_inode(struct inode *);
@@ -292,11 +294,8 @@ int nilfs_gccache_submit_read_data(struct inode *, sector_t, sector_t, __u64,
 int nilfs_gccache_submit_read_node(struct inode *, sector_t, __u64,
 				   struct buffer_head **);
 int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *);
-int nilfs_init_gccache(struct the_nilfs *);
-void nilfs_destroy_gccache(struct the_nilfs *);
-void nilfs_clear_gcinode(struct inode *);
-struct inode *nilfs_gc_iget(struct the_nilfs *, ino_t, __u64);
-void nilfs_remove_all_gcinode(struct the_nilfs *);
+int nilfs_init_gcinode(struct inode *inode);
+void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs);
 
 /* gcdat.c */
 int nilfs_init_gcdat_inode(struct the_nilfs *);
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 9fd051a33c4f..9cf71389f369 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -366,8 +366,7 @@ static int nilfs_segctor_reset_segment_buffer(struct nilfs_sc_info *sci)
 
 	if (nilfs_doing_gc())
 		flags = NILFS_SS_GC;
-	err = nilfs_segbuf_reset(segbuf, flags, sci->sc_seg_ctime,
-				 sci->sc_sbi->s_nilfs->ns_cno);
+	err = nilfs_segbuf_reset(segbuf, flags, sci->sc_seg_ctime, sci->sc_cno);
 	if (unlikely(err))
 		return err;
 
@@ -440,17 +439,26 @@ static void nilfs_segctor_end_finfo(struct nilfs_sc_info *sci,
 	struct nilfs_finfo *finfo;
 	struct nilfs_inode_info *ii;
 	struct nilfs_segment_buffer *segbuf;
+	__u64 cno;
 
 	if (sci->sc_blk_cnt == 0)
 		return;
 
 	ii = NILFS_I(inode);
+
+	if (test_bit(NILFS_I_GCINODE, &ii->i_state))
+		cno = ii->i_cno;
+	else if (NILFS_ROOT_METADATA_FILE(inode->i_ino))
+		cno = 0;
+	else
+		cno = sci->sc_cno;
+
 	finfo = nilfs_segctor_map_segsum_entry(sci, &sci->sc_finfo_ptr,
 						 sizeof(*finfo));
 	finfo->fi_ino = cpu_to_le64(inode->i_ino);
 	finfo->fi_nblocks = cpu_to_le32(sci->sc_blk_cnt);
 	finfo->fi_ndatablk = cpu_to_le32(sci->sc_datablk_cnt);
-	finfo->fi_cno = cpu_to_le64(ii->i_cno);
+	finfo->fi_cno = cpu_to_le64(cno);
 
 	segbuf = sci->sc_curseg;
 	segbuf->sb_sum.sumbytes = sci->sc_binfo_ptr.offset +
@@ -1976,7 +1984,6 @@ static int nilfs_segctor_check_in_files(struct nilfs_sc_info *sci,
 					struct nilfs_sb_info *sbi)
 {
 	struct nilfs_inode_info *ii, *n;
-	__u64 cno = sbi->s_nilfs->ns_cno;
 
 	spin_lock(&sbi->s_inode_lock);
  retry:
@@ -2002,7 +2009,6 @@ static int nilfs_segctor_check_in_files(struct nilfs_sc_info *sci,
 				brelse(ibh);
 			goto retry;
 		}
-		ii->i_cno = cno;
 
 		clear_bit(NILFS_I_QUEUED, &ii->i_state);
 		set_bit(NILFS_I_BUSY, &ii->i_state);
@@ -2011,8 +2017,6 @@ static int nilfs_segctor_check_in_files(struct nilfs_sc_info *sci,
 	}
 	spin_unlock(&sbi->s_inode_lock);
 
-	NILFS_I(sbi->s_ifile)->i_cno = cno;
-
 	return 0;
 }
 
@@ -2021,19 +2025,13 @@ static void nilfs_segctor_check_out_files(struct nilfs_sc_info *sci,
 {
 	struct nilfs_transaction_info *ti = current->journal_info;
 	struct nilfs_inode_info *ii, *n;
-	__u64 cno = sbi->s_nilfs->ns_cno;
 
 	spin_lock(&sbi->s_inode_lock);
 	list_for_each_entry_safe(ii, n, &sci->sc_dirty_files, i_dirty) {
 		if (!test_and_clear_bit(NILFS_I_UPDATED, &ii->i_state) ||
-		    test_bit(NILFS_I_DIRTY, &ii->i_state)) {
-			/* The current checkpoint number (=nilfs->ns_cno) is
-			   changed between check-in and check-out only if the
-			   super root is written out.  So, we can update i_cno
-			   for the inodes that remain in the dirty list. */
-			ii->i_cno = cno;
+		    test_bit(NILFS_I_DIRTY, &ii->i_state))
 			continue;
-		}
+
 		clear_bit(NILFS_I_BUSY, &ii->i_state);
 		brelse(ii->i_bh);
 		ii->i_bh = NULL;
@@ -2054,6 +2052,7 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 	int err;
 
 	sci->sc_stage.scnt = NILFS_ST_INIT;
+	sci->sc_cno = nilfs->ns_cno;
 
 	err = nilfs_segctor_check_in_files(sci, sbi);
 	if (unlikely(err))
@@ -2452,9 +2451,8 @@ nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
 	list_for_each_entry_safe(ii, n, head, i_dirty) {
 		if (!test_bit(NILFS_I_UPDATED, &ii->i_state))
 			continue;
-		hlist_del_init(&ii->vfs_inode.i_hash);
 		list_del_init(&ii->i_dirty);
-		nilfs_clear_gcinode(&ii->vfs_inode);
+		iput(&ii->vfs_inode);
 	}
 }
 
diff --git a/fs/nilfs2/segment.h b/fs/nilfs2/segment.h
index 17c487bd8152..675d932148a4 100644
--- a/fs/nilfs2/segment.h
+++ b/fs/nilfs2/segment.h
@@ -107,6 +107,7 @@ struct nilfs_segsum_pointer {
  * @sc_datablk_cnt: Data block count of a file
  * @sc_nblk_this_inc: Number of blocks included in the current logical segment
  * @sc_seg_ctime: Creation time
+ * @sc_cno: checkpoint number of current log
  * @sc_flags: Internal flags
  * @sc_state_lock: spinlock for sc_state and so on
  * @sc_state: Segctord state flags
@@ -156,7 +157,7 @@ struct nilfs_sc_info {
 	unsigned long		sc_datablk_cnt;
 	unsigned long		sc_nblk_this_inc;
 	time_t			sc_seg_ctime;
-
+	__u64			sc_cno;
 	unsigned long		sc_flags;
 
 	spinlock_t		sc_state_lock;
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 922263393c76..452004b4050d 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -156,6 +156,7 @@ struct inode *nilfs_alloc_inode_common(struct the_nilfs *nilfs)
 		return NULL;
 	ii->i_bh = NULL;
 	ii->i_state = 0;
+	ii->i_cno = 0;
 	ii->vfs_inode.i_version = 1;
 	nilfs_btnode_cache_init(&ii->i_btnode_cache, nilfs->ns_bdi);
 	return &ii->vfs_inode;
@@ -168,6 +169,12 @@ struct inode *nilfs_alloc_inode(struct super_block *sb)
 
 void nilfs_destroy_inode(struct inode *inode)
 {
+	struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
+
+	if (mdi) {
+		kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
+		kfree(mdi);
+	}
 	kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 }
 
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index ba7c10c917fc..6a012b9e1b31 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -87,8 +87,8 @@ static struct the_nilfs *alloc_nilfs(struct block_device *bdev)
 	init_rwsem(&nilfs->ns_writer_sem);
 	INIT_LIST_HEAD(&nilfs->ns_list);
 	INIT_LIST_HEAD(&nilfs->ns_supers);
+	INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
 	spin_lock_init(&nilfs->ns_last_segment_lock);
-	nilfs->ns_gc_inodes_h = NULL;
 	init_rwsem(&nilfs->ns_segctor_sem);
 
 	return nilfs;
@@ -164,7 +164,6 @@ void put_nilfs(struct the_nilfs *nilfs)
 		nilfs_mdt_destroy(nilfs->ns_gc_dat);
 	}
 	if (nilfs_init(nilfs)) {
-		nilfs_destroy_gccache(nilfs);
 		brelse(nilfs->ns_sbh[0]);
 		brelse(nilfs->ns_sbh[1]);
 	}
@@ -468,8 +467,8 @@ static unsigned long long nilfs_max_size(unsigned int blkbits)
 static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
 				   struct nilfs_super_block *sbp)
 {
-	if (le32_to_cpu(sbp->s_rev_level) != NILFS_CURRENT_REV) {
-		printk(KERN_ERR "NILFS: revision mismatch "
+	if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) {
+		printk(KERN_ERR "NILFS: unsupported revision "
 		       "(superblock rev.=%d.%d, current rev.=%d.%d). "
 		       "Please check the version of mkfs.nilfs.\n",
 		       le32_to_cpu(sbp->s_rev_level),
@@ -736,11 +735,6 @@ int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
 	if (err)
 		goto failed_sbh;
 
-	/* Initialize gcinode cache */
-	err = nilfs_init_gccache(nilfs);
-	if (err)
-		goto failed_sbh;
-
 	set_nilfs_init(nilfs);
 	err = 0;
  out:
diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index f785a7b0ab99..c7ecd0c623a3 100644
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -81,7 +81,6 @@ enum {
  * @ns_sufile: segusage file inode
  * @ns_gc_dat: shadow inode of the DAT file inode for GC
  * @ns_gc_inodes: dummy inodes to keep live blocks
- * @ns_gc_inodes_h: hash list to keep dummy inode holding live blocks
  * @ns_blocksize_bits: bit length of block size
  * @ns_blocksize: block size
  * @ns_nsegments: number of segments in filesystem
@@ -165,9 +164,8 @@ struct the_nilfs {
 	struct inode	       *ns_sufile;
 	struct inode	       *ns_gc_dat;
 
-	/* GC inode list and hash table head */
+	/* GC inode list */
 	struct list_head	ns_gc_inodes;
-	struct hlist_head      *ns_gc_inodes_h;
 
 	/* Disk layout information (static) */
 	unsigned int		ns_blocksize_bits;
@@ -182,9 +180,6 @@ struct the_nilfs {
 	u32			ns_crc_seed;
 };
 
-#define NILFS_GCINODE_HASH_BITS		8
-#define NILFS_GCINODE_HASH_SIZE		(1<<NILFS_GCINODE_HASH_BITS)
-
 #define THE_NILFS_FNS(bit, name)					\
 static inline void set_nilfs_##name(struct the_nilfs *nilfs)		\
 {									\
diff --git a/include/linux/nilfs2_fs.h b/include/linux/nilfs2_fs.h
index f5487b6f91ed..bcdb34c68d08 100644
--- a/include/linux/nilfs2_fs.h
+++ b/include/linux/nilfs2_fs.h
@@ -229,6 +229,7 @@ struct nilfs_super_block {
  */
 #define NILFS_CURRENT_REV	2	/* current major revision */
 #define NILFS_MINOR_REV		0	/* minor revision */
+#define NILFS_MIN_SUPP_REV	2	/* minimum supported revision */
 
 /*
  * Feature set definitions
@@ -270,6 +271,14 @@ struct nilfs_super_block {
 					   segments */
 
 /*
+ * We call DAT, cpfile, and sufile root metadata files.  Inodes of
+ * these files are written in super root block instead of ifile, and
+ * garbage collector doesn't keep any past versions of these files.
+ */
+#define NILFS_ROOT_METADATA_FILE(ino) \
+	((ino) >= NILFS_DAT_INO && (ino) <= NILFS_SUFILE_INO)
+
+/*
  * bytes offset of secondary super block
  */
 #define NILFS_SB2_OFFSET_BYTES(devsize)	((((devsize) >> 12) - 1) << 12)