Merge branch 'for_linus' into for_linus_merged

Conflicts:
fs/ext4/ioctl.c

Documentation/filesystems/ext4.txt

···
 			      behaviour may change in the future as it is
 			      not necessary and has been done this way only
 			      for sake of simplicity.
+
+ EXT4_IOC_RESIZE_FS	      Resize the filesystem to a new size.  The number
+			      of blocks of resized filesystem is passed in via
+			      64 bit integer argument.  The kernel allocates
+			      bitmaps and inode table, the userspace tool thus
+			      just passes the new number of blocks.
+
 ..............................................................................
 
 References

fs/ext4/balloc.c

···
 
 #include <trace/events/ext4.h>
 
+static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
+					    ext4_group_t block_group);
 /*
  * balloc.c contains the blocks allocation and deallocation routines
  */
···
  * This function returns the number of file system metadata clusters at
  * the beginning of a block group, including the reserved gdt blocks.
  */
-unsigned ext4_num_base_meta_clusters(struct super_block *sb,
+static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
 				     ext4_group_t block_group)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);

fs/ext4/ext4.h

···
 	__u32 free_blocks_count;
 };
 
+/* Indexes used to index group tables in ext4_new_group_data */
+enum {
+	BLOCK_BITMAP = 0,	/* block bitmap */
+	INODE_BITMAP,		/* inode bitmap */
+	INODE_TABLE,		/* inode tables */
+	GROUP_TABLE_COUNT,
+};
+
 /*
  * Flags used by ext4_map_blocks()
  */
···
  /* note ioctl 11 reserved for filesystem-independent FIEMAP ioctl */
 #define EXT4_IOC_ALLOC_DA_BLKS		_IO('f', 12)
 #define EXT4_IOC_MOVE_EXT		_IOWR('f', 15, struct move_extent)
+#define EXT4_IOC_RESIZE_FS		_IOW('f', 16, __u64)
 
 #if defined(__KERNEL__) && defined(CONFIG_COMPAT)
 /*
···
 #define test_opt2(sb, opt)		(EXT4_SB(sb)->s_mount_opt2 & \
 					 EXT4_MOUNT2_##opt)
 
-#define ext4_set_bit			__test_and_set_bit_le
+#define ext4_test_and_set_bit		__test_and_set_bit_le
+#define ext4_set_bit			__set_bit_le
 #define ext4_set_bit_atomic		ext2_set_bit_atomic
-#define ext4_clear_bit			__test_and_clear_bit_le
+#define ext4_test_and_clear_bit		__test_and_clear_bit_le
+#define ext4_clear_bit			__clear_bit_le
 #define ext4_clear_bit_atomic		ext2_clear_bit_atomic
 #define ext4_test_bit			test_bit_le
-#define ext4_find_first_zero_bit	find_first_zero_bit_le
 #define ext4_find_next_zero_bit		find_next_zero_bit_le
 #define ext4_find_next_bit		find_next_bit_le
 
···
 #define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE	0x0040
 #define EXT4_FEATURE_RO_COMPAT_QUOTA		0x0100
 #define EXT4_FEATURE_RO_COMPAT_BIGALLOC		0x0200
+#define EXT4_FEATURE_RO_COMPAT_METADATA_CSUM	0x0400
 
 #define EXT4_FEATURE_INCOMPAT_COMPRESSION	0x0001
 #define EXT4_FEATURE_INCOMPAT_FILETYPE		0x0002
···
 #define EXT4_FEATURE_INCOMPAT_FLEX_BG		0x0200
 #define EXT4_FEATURE_INCOMPAT_EA_INODE		0x0400 /* EA in inode */
 #define EXT4_FEATURE_INCOMPAT_DIRDATA		0x1000 /* data in dirent */
+#define EXT4_FEATURE_INCOMPAT_INLINEDATA	0x2000 /* data in inode */
+#define EXT4_FEATURE_INCOMPAT_LARGEDIR		0x4000 /* >2GB or 3-lvl htree */
 
 #define EXT2_FEATURE_COMPAT_SUPP	EXT4_FEATURE_COMPAT_EXT_ATTR
 #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT4_FEATURE_INCOMPAT_FILETYPE| \
···
 extern unsigned ext4_free_clusters_after_init(struct super_block *sb,
 					      ext4_group_t block_group,
 					      struct ext4_group_desc *gdp);
-extern unsigned ext4_num_base_meta_clusters(struct super_block *sb,
-					    ext4_group_t block_group);
 extern unsigned ext4_num_overhead_clusters(struct super_block *sb,
 					   ext4_group_t block_group,
 					   struct ext4_group_desc *gdp);
···
 extern void ext4_set_aops(struct inode *inode);
 extern int ext4_writepage_trans_blocks(struct inode *);
 extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks);
-extern int ext4_block_truncate_page(handle_t *handle,
-		struct address_space *mapping, loff_t from);
-extern int ext4_block_zero_page_range(handle_t *handle,
-		struct address_space *mapping, loff_t from, loff_t length);
 extern int ext4_discard_partial_page_buffers(handle_t *handle,
 		struct address_space *mapping, loff_t from,
-		loff_t length, int flags);
-extern int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
-		struct inode *inode, struct page *page, loff_t from,
 		loff_t length, int flags);
 extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
 extern qsize_t *ext4_get_reserved_space(struct inode *inode);
···
 extern int ext4_group_extend(struct super_block *sb,
 				struct ext4_super_block *es,
 				ext4_fsblk_t n_blocks_count);
+extern int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count);
 
 /* super.c */
 extern void *ext4_kvmalloc(size_t size, gfp_t flags);

fs/ext4/extents.c

···
 	ext4_lblk_t i, pg_lblk;
 	pgoff_t index;
 
+	if (!test_opt(inode->i_sb, DELALLOC))
+		return 0;
+
 	/* reverse search wont work if fs block size is less than page size */
 	if (inode->i_blkbits < PAGE_CACHE_SHIFT)
 		search_hint_reverse = 0;
···
 	int err = 0;
 	ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
 
-	ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical"
-		  "block %llu, max_blocks %u, flags %d, allocated %u",
+	ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical "
+		  "block %llu, max_blocks %u, flags %x, allocated %u\n",
 		  inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
 		  flags, allocated);
 	ext4_ext_show_leaf(inode, path);
···
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	ext4_lblk_t c_offset = map->m_lblk & (sbi->s_cluster_ratio-1);
 	ext4_lblk_t ex_cluster_start, ex_cluster_end;
-	ext4_lblk_t rr_cluster_start, rr_cluster_end;
+	ext4_lblk_t rr_cluster_start;
 	ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
 	ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
 	unsigned short ee_len = ext4_ext_get_actual_len(ex);
···
 
 	/* The requested region passed into ext4_map_blocks() */
 	rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
-	rr_cluster_end = EXT4_B2C(sbi, map->m_lblk + map->m_len - 1);
 
 	if ((rr_cluster_start == ex_cluster_end) ||
 	    (rr_cluster_start == ex_cluster_start)) {

fs/ext4/ialloc.c

···
 		fatal = ext4_journal_get_write_access(handle, bh2);
 	}
 	ext4_lock_group(sb, block_group);
-	cleared = ext4_clear_bit(bit, bitmap_bh->b_data);
+	cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
 	if (fatal || !cleared) {
 		ext4_unlock_group(sb, block_group);
 		goto out;
···
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	ext4_group_t real_ngroups = ext4_get_groups_count(sb);
 	int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
-	unsigned int freei, avefreei;
+	unsigned int freei, avefreei, grp_free;
 	ext4_fsblk_t freeb, avefreec;
 	unsigned int ndirs;
 	int max_dirs, min_inodes;
···
 	for (i = 0; i < ngroups; i++) {
 		grp = (parent_group + i) % ngroups;
 		desc = ext4_get_group_desc(sb, grp, NULL);
-		if (desc && ext4_free_inodes_count(sb, desc) &&
-		    ext4_free_inodes_count(sb, desc) >= avefreei) {
+		grp_free = ext4_free_inodes_count(sb, desc);
+		if (desc && grp_free && grp_free >= avefreei) {
 			*group = grp;
 			return 0;
 		}
···
 	 */
 	down_read(&grp->alloc_sem);
 	ext4_lock_group(sb, group);
-	if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
+	if (ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data)) {
 		/* not a free inode */
 		retval = 1;
 		goto err_ret;
···
 	if (IS_DIRSYNC(inode))
 		ext4_handle_sync(handle);
 	if (insert_inode_locked(inode) < 0) {
-		err = -EINVAL;
-		goto fail_drop;
+		/*
+		 * Likely a bitmap corruption causing inode to be allocated
+		 * twice.
+		 */
+		err = -EIO;
+		goto fail;
 	}
 	spin_lock(&sbi->s_next_gen_lock);
 	inode->i_generation = sbi->s_next_generation++;

fs/ext4/inode.c

···
 static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
+static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
+		struct inode *inode, struct page *page, loff_t from,
+		loff_t length, int flags);
 
 /*
  * Test whether an inode is a fast symlink.
···
 	if (!io_end || !size)
 		goto out;
 
-	ext_debug("ext4_end_io_dio(): io_end 0x%p"
+	ext_debug("ext4_end_io_dio(): io_end 0x%p "
 		  "for inode %lu, iocb 0x%p, offset %llu, size %llu\n",
  		  iocb->private, io_end->inode->i_ino, iocb, offset,
 		  size);
···
  *
  * Returns zero on sucess or negative on failure.
  */
-int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
+static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
 		struct inode *inode, struct page *page, loff_t from,
 		loff_t length, int flags)
 {
···
 		pos += range_to_discard;
 	}
 
-	return err;
-}
-
-/*
- * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
- * up to the end of the block which corresponds to `from'.
- * This required during truncate. We need to physically zero the tail end
- * of that block so it doesn't yield old data if the file is later grown.
- */
-int ext4_block_truncate_page(handle_t *handle,
-		struct address_space *mapping, loff_t from)
-{
-	unsigned offset = from & (PAGE_CACHE_SIZE-1);
-	unsigned length;
-	unsigned blocksize;
-	struct inode *inode = mapping->host;
-
-	blocksize = inode->i_sb->s_blocksize;
-	length = blocksize - (offset & (blocksize - 1));
-
-	return ext4_block_zero_page_range(handle, mapping, from, length);
-}
-
-/*
- * ext4_block_zero_page_range() zeros out a mapping of length 'length'
- * starting from file offset 'from'.  The range to be zero'd must
- * be contained with in one block.  If the specified range exceeds
- * the end of the block it will be shortened to end of the block
- * that cooresponds to 'from'
- */
-int ext4_block_zero_page_range(handle_t *handle,
-		struct address_space *mapping, loff_t from, loff_t length)
-{
-	ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
-	unsigned offset = from & (PAGE_CACHE_SIZE-1);
-	unsigned blocksize, max, pos;
-	ext4_lblk_t iblock;
-	struct inode *inode = mapping->host;
-	struct buffer_head *bh;
-	struct page *page;
-	int err = 0;
-
-	page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
-				   mapping_gfp_mask(mapping) & ~__GFP_FS);
-	if (!page)
-		return -ENOMEM;
-
-	blocksize = inode->i_sb->s_blocksize;
-	max = blocksize - (offset & (blocksize - 1));
-
-	/*
-	 * correct length if it does not fall between
-	 * 'from' and the end of the block
-	 */
-	if (length > max || length < 0)
-		length = max;
-
-	iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
-
-	if (!page_has_buffers(page))
-		create_empty_buffers(page, blocksize, 0);
-
-	/* Find the buffer that contains "offset" */
-	bh = page_buffers(page);
-	pos = blocksize;
-	while (offset >= pos) {
-		bh = bh->b_this_page;
-		iblock++;
-		pos += blocksize;
-	}
-
-	err = 0;
-	if (buffer_freed(bh)) {
-		BUFFER_TRACE(bh, "freed: skip");
-		goto unlock;
-	}
-
-	if (!buffer_mapped(bh)) {
-		BUFFER_TRACE(bh, "unmapped");
-		ext4_get_block(inode, iblock, bh, 0);
-		/* unmapped? It's a hole - nothing to do */
-		if (!buffer_mapped(bh)) {
-			BUFFER_TRACE(bh, "still unmapped");
-			goto unlock;
-		}
-	}
-
-	/* Ok, it's mapped. Make sure it's up-to-date */
-	if (PageUptodate(page))
-		set_buffer_uptodate(bh);
-
-	if (!buffer_uptodate(bh)) {
-		err = -EIO;
-		ll_rw_block(READ, 1, &bh);
-		wait_on_buffer(bh);
-		/* Uhhuh. Read error. Complain and punt. */
-		if (!buffer_uptodate(bh))
-			goto unlock;
-	}
-
-	if (ext4_should_journal_data(inode)) {
-		BUFFER_TRACE(bh, "get write access");
-		err = ext4_journal_get_write_access(handle, bh);
-		if (err)
-			goto unlock;
-	}
-
-	zero_user(page, offset, length);
-
-	BUFFER_TRACE(bh, "zeroed end of block");
-
-	err = 0;
-	if (ext4_should_journal_data(inode)) {
-		err = ext4_handle_dirty_metadata(handle, inode, bh);
-	} else
-		mark_buffer_dirty(bh);
-
-unlock:
-	unlock_page(page);
-	page_cache_release(page);
 	return err;
 }
 
···
 		return 0;
 	if (is_journal_aborted(journal))
 		return -EROFS;
+	/* We have to allocate physical blocks for delalloc blocks
+	 * before flushing journal. otherwise delalloc blocks can not
+	 * be allocated any more. even more truncate on delalloc blocks
+	 * could trigger BUG by flushing delalloc blocks in journal.
+	 * There is no delalloc block in non-journal data mode.
+	 */
+	if (val && test_opt(inode->i_sb, DELALLOC)) {
+		err = ext4_alloc_da_blocks(inode);
+		if (err < 0)
+			return err;
+	}
 
 	jbd2_journal_lock_updates(journal);
-	jbd2_journal_flush(journal);
 
 	/*
 	 * OK, there are no updates running now, and all cached data is
···
 
 	if (val)
 		ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
-	else
+	else {
+		jbd2_journal_flush(journal);
 		ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
+	}
 	ext4_set_aops(inode);
 
 	jbd2_journal_unlock_updates(journal);

fs/ext4/ioctl.c

···
 #include "ext4_jbd2.h"
 #include "ext4.h"
 
+#define MAX_32_NUM ((((unsigned long long) 1) << 32) - 1)
+
 long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = filp->f_dentry->d_inode;
···
 		if (err)
 			return err;
 
-		if (get_user(n_blocks_count, (__u32 __user *)arg))
-			return -EFAULT;
+		if (get_user(n_blocks_count, (__u32 __user *)arg)) {
+			err = -EFAULT;
+			goto group_extend_out;
+		}
 
 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
 			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
 			ext4_msg(sb, KERN_ERR,
 				 "Online resizing not supported with bigalloc");
-			return -EOPNOTSUPP;
+			err = -EOPNOTSUPP;
+			goto group_extend_out;
 		}
 
 		err = mnt_want_write_file(filp);
 		if (err)
-			return err;
+			goto group_extend_out;
 
 		err = ext4_group_extend(sb, EXT4_SB(sb)->s_es, n_blocks_count);
 		if (EXT4_SB(sb)->s_journal) {
···
 		if (err == 0)
 			err = err2;
 		mnt_drop_write_file(filp);
+group_extend_out:
 		ext4_resize_end(sb);
-
 		return err;
 	}
 
···
 		err = ext4_move_extents(filp, donor_filp, me.orig_start,
 					me.donor_start, me.len, &me.moved_len);
 		mnt_drop_write_file(filp);
-		if (me.moved_len > 0)
-			file_remove_suid(donor_filp);
+		mnt_drop_write(filp->f_path.mnt);
 
 		if (copy_to_user((struct move_extent __user *)arg,
 				 &me, sizeof(me)))
···
 			return err;
 
 		if (copy_from_user(&input, (struct ext4_new_group_input __user *)arg,
-				sizeof(input)))
-			return -EFAULT;
+				sizeof(input))) {
+			err = -EFAULT;
+			goto group_add_out;
+		}
 
 		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
 			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
 			ext4_msg(sb, KERN_ERR,
 				 "Online resizing not supported with bigalloc");
-			return -EOPNOTSUPP;
+			err = -EOPNOTSUPP;
+			goto group_add_out;
 		}
 
 		err = mnt_want_write_file(filp);
 		if (err)
-			return err;
+			goto group_add_out;
 
 		err = ext4_group_add(sb, &input);
 		if (EXT4_SB(sb)->s_journal) {
···
 		if (err == 0)
 			err = err2;
 		mnt_drop_write_file(filp);
+group_add_out:
 		ext4_resize_end(sb);
-
 		return err;
 	}
 
···
 			return err;
 		err = ext4_alloc_da_blocks(inode);
 		mnt_drop_write_file(filp);
+		return err;
+	}
+
+	case EXT4_IOC_RESIZE_FS: {
+		ext4_fsblk_t n_blocks_count;
+		struct super_block *sb = inode->i_sb;
+		int err = 0, err2 = 0;
+
+		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+			       EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online resizing not (yet) supported with bigalloc");
+			return -EOPNOTSUPP;
+		}
+
+		if (EXT4_HAS_INCOMPAT_FEATURE(sb,
+			       EXT4_FEATURE_INCOMPAT_META_BG)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online resizing not (yet) supported with meta_bg");
+			return -EOPNOTSUPP;
+		}
+
+		if (copy_from_user(&n_blocks_count, (__u64 __user *)arg,
+				   sizeof(__u64))) {
+			return -EFAULT;
+		}
+
+		if (n_blocks_count > MAX_32_NUM &&
+		    !EXT4_HAS_INCOMPAT_FEATURE(sb,
+					       EXT4_FEATURE_INCOMPAT_64BIT)) {
+			ext4_msg(sb, KERN_ERR,
+				 "File system only supports 32-bit block numbers");
+			return -EOPNOTSUPP;
+		}
+
+		err = ext4_resize_begin(sb);
+		if (err)
+			return err;
+
+		err = mnt_want_write(filp->f_path.mnt);
+		if (err)
+			goto resizefs_out;
+
+		err = ext4_resize_fs(sb, n_blocks_count);
+		if (EXT4_SB(sb)->s_journal) {
+			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
+			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
+			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
+		}
+		if (err == 0)
+			err = err2;
+		mnt_drop_write(filp->f_path.mnt);
+resizefs_out:
+		ext4_resize_end(sb);
 		return err;
 	}
 
···
 	}
 	case EXT4_IOC_MOVE_EXT:
 	case FITRIM:
+	case EXT4_IOC_RESIZE_FS:
 		break;
 	default:
 		return -ENOIOCTLCMD;

fs/ext4/mballoc.c

···
 	ext4_group_t group;
 	ext4_grpblk_t bit;
 
-	trace_ext4_mb_release_group_pa(pa);
+	trace_ext4_mb_release_group_pa(sb, pa);
 	BUG_ON(pa->pa_deleted == 0);
 	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
 	BUG_ON(group != e4b->bd_group && pa->pa_len != 0);

fs/ext4/resize.c

···
 	return err;
 }
 
+/*
+ * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
+ * group each time.
+ */
+struct ext4_new_flex_group_data {
+	struct ext4_new_group_data *groups;	/* new_group_data for groups
+						   in the flex group */
+	__u16 *bg_flags;			/* block group flags of groups
+						   in @groups */
+	ext4_group_t count;			/* number of groups in @groups
+						 */
+};
+
+/*
+ * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
+ * @flexbg_size.
+ *
+ * Returns NULL on failure otherwise address of the allocated structure.
+ */
+static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
+{
+	struct ext4_new_flex_group_data *flex_gd;
+
+	flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
+	if (flex_gd == NULL)
+		goto out3;
+
+	flex_gd->count = flexbg_size;
+
+	flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
+				  flexbg_size, GFP_NOFS);
+	if (flex_gd->groups == NULL)
+		goto out2;
+
+	flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
+	if (flex_gd->bg_flags == NULL)
+		goto out1;
+
+	return flex_gd;
+
+out1:
+	kfree(flex_gd->groups);
+out2:
+	kfree(flex_gd);
+out3:
+	return NULL;
+}
+
+static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
+{
+	kfree(flex_gd->bg_flags);
+	kfree(flex_gd->groups);
+	kfree(flex_gd);
+}
+
+/*
+ * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
+ * and inode tables for a flex group.
+ *
+ * This function is used by 64bit-resize.  Note that this function allocates
+ * group tables from the 1st group of groups contained by @flexgd, which may
+ * be a partial of a flex group.
+ *
+ * @sb: super block of fs to which the groups belongs
+ */
+static void ext4_alloc_group_tables(struct super_block *sb,
+				struct ext4_new_flex_group_data *flex_gd,
+				int flexbg_size)
+{
+	struct ext4_new_group_data *group_data = flex_gd->groups;
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	ext4_fsblk_t start_blk;
+	ext4_fsblk_t last_blk;
+	ext4_group_t src_group;
+	ext4_group_t bb_index = 0;
+	ext4_group_t ib_index = 0;
+	ext4_group_t it_index = 0;
+	ext4_group_t group;
+	ext4_group_t last_group;
+	unsigned overhead;
+
+	BUG_ON(flex_gd->count == 0 || group_data == NULL);
+
+	src_group = group_data[0].group;
+	last_group  = src_group + flex_gd->count - 1;
+
+	BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
+	       (last_group & ~(flexbg_size - 1))));
+next_group:
+	group = group_data[0].group;
+	start_blk = ext4_group_first_block_no(sb, src_group);
+	last_blk = start_blk + group_data[src_group - group].blocks_count;
+
+	overhead = ext4_bg_has_super(sb, src_group) ?
+		   (1 + ext4_bg_num_gdb(sb, src_group) +
+		    le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
+
+	start_blk += overhead;
+
+	BUG_ON(src_group >= group_data[0].group + flex_gd->count);
+	/* We collect contiguous blocks as much as possible. */
+	src_group++;
+	for (; src_group <= last_group; src_group++)
+		if (!ext4_bg_has_super(sb, src_group))
+			last_blk += group_data[src_group - group].blocks_count;
+		else
+			break;
+
+	/* Allocate block bitmaps */
+	for (; bb_index < flex_gd->count; bb_index++) {
+		if (start_blk >= last_blk)
+			goto next_group;
+		group_data[bb_index].block_bitmap = start_blk++;
+		ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
+		group -= group_data[0].group;
+		group_data[group].free_blocks_count--;
+		if (flexbg_size > 1)
+			flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
+	}
+
+	/* Allocate inode bitmaps */
+	for (; ib_index < flex_gd->count; ib_index++) {
+		if (start_blk >= last_blk)
+			goto next_group;
+		group_data[ib_index].inode_bitmap = start_blk++;
+		ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
+		group -= group_data[0].group;
+		group_data[group].free_blocks_count--;
+		if (flexbg_size > 1)
+			flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
+	}
+
+	/* Allocate inode tables */
+	for (; it_index < flex_gd->count; it_index++) {
+		if (start_blk + EXT4_SB(sb)->s_itb_per_group > last_blk)
+			goto next_group;
+		group_data[it_index].inode_table = start_blk;
+		ext4_get_group_no_and_offset(sb, start_blk, &group, NULL);
+		group -= group_data[0].group;
+		group_data[group].free_blocks_count -=
+					EXT4_SB(sb)->s_itb_per_group;
+		if (flexbg_size > 1)
+			flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
+
+		start_blk += EXT4_SB(sb)->s_itb_per_group;
+	}
+
+	if (test_opt(sb, DEBUG)) {
+		int i;
+		group = group_data[0].group;
+
+		printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
+		       "%d groups, flexbg size is %d:\n", flex_gd->count,
+		       flexbg_size);
+
+		for (i = 0; i < flex_gd->count; i++) {
+			printk(KERN_DEBUG "adding %s group %u: %u "
+			       "blocks (%d free)\n",
+			       ext4_bg_has_super(sb, group + i) ? "normal" :
+			       "no-super", group + i,
+			       group_data[i].blocks_count,
+			       group_data[i].free_blocks_count);
+		}
+	}
+}
+
 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
 				  ext4_fsblk_t blk)
 {
···
 }
 
 /*
- * Set up the block and inode bitmaps, and the inode table for the new group.
+ * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
+ *
+ * Helper function for ext4_setup_new_group_blocks() which set .
+ *
+ * @sb: super block
+ * @handle: journal handle
+ * @flex_gd: flex group data
+ */
+static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
+			struct ext4_new_flex_group_data *flex_gd,
+			ext4_fsblk_t block, ext4_group_t count)
+{
+	ext4_group_t count2;
+
+	ext4_debug("mark blocks [%llu/%u] used\n", block, count);
+	for (count2 = count; count > 0; count -= count2, block += count2) {
+		ext4_fsblk_t start;
+		struct buffer_head *bh;
+		ext4_group_t group;
+		int err;
+
+		ext4_get_group_no_and_offset(sb, block, &group, NULL);
+		start = ext4_group_first_block_no(sb, group);
+		group -= flex_gd->groups[0].group;
+
+		count2 = sb->s_blocksize * 8 - (block - start);
+		if (count2 > count)
+			count2 = count;
+
+		if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
+			BUG_ON(flex_gd->count > 1);
+			continue;
+		}
+
+		err = extend_or_restart_transaction(handle, 1);
+		if (err)
+			return err;
+
+		bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
+		if (!bh)
+			return -EIO;
+
+		err = ext4_journal_get_write_access(handle, bh);
+		if (err)
+			return err;
+		ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
+			   block - start, count2);
+		ext4_set_bits(bh->b_data, block - start, count2);
+
+		err = ext4_handle_dirty_metadata(handle, NULL, bh);
+		if (unlikely(err))
+			return err;
+		brelse(bh);
+	}
+
+	return 0;
+}
+
+/*
+ * Set up the block and inode bitmaps, and the inode table for the new groups.
  * This doesn't need to be part of the main transaction, since we are only
  * changing blocks outside the actual filesystem.  We still do journaling to
  * ensure the recovery is correct in case of a failure just after resize.
  * If any part of this fails, we simply abort the resize.
+ *
+ * setup_new_flex_group_blocks handles a flex group as follow:
+ *  1. copy super block and GDT, and initialize group tables if necessary.
+ *     In this step, we only set bits in blocks bitmaps for blocks taken by
+ *     super block and GDT.
+ *  2. allocate group tables in block bitmaps, that is, set bits in block
+ *     bitmap for blocks taken by group tables.
  */
-static int setup_new_group_blocks(struct super_block *sb,
-				  struct ext4_new_group_data *input)
+static int setup_new_flex_group_blocks(struct super_block *sb,
+				struct ext4_new_flex_group_data *flex_gd)
 {
-	struct ext4_sb_info *sbi = EXT4_SB(sb);
-	ext4_fsblk_t start = ext4_group_first_block_no(sb, input->group);
-	int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
-		le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
-	unsigned long gdblocks = ext4_bg_num_gdb(sb, input->group);
-	struct buffer_head *bh;
-	handle_t *handle;
+	int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
+	ext4_fsblk_t start;
 	ext4_fsblk_t block;
-	ext4_grpblk_t bit;
-	int i;
-	int err = 0, err2;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	struct ext4_new_group_data *group_data = flex_gd->groups;
+	__u16 *bg_flags = flex_gd->bg_flags;
+	handle_t *handle;
+	ext4_group_t group, count;
+	struct buffer_head *bh = NULL;
+	int reserved_gdb, i, j, err = 0, err2;
+
+	BUG_ON(!flex_gd->count || !group_data ||
+	       group_data[0].group != sbi->s_groups_count);
+
+	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
 
 	/* This transaction may be extended/restarted along the way */
 	handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
-
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 
-	BUG_ON(input->group != sbi->s_groups_count);
+	group = group_data[0].group;
+	for (i = 0; i < flex_gd->count; i++, group++) {
+		unsigned long gdblocks;
 
-	/* Copy all of the GDT blocks into the backup in this group */
-	for (i = 0, bit = 1, block = start + 1;
-	     i < gdblocks; i++, block++, bit++) {
-		struct buffer_head *gdb;
+		gdblocks = ext4_bg_num_gdb(sb, group);
+		start = ext4_group_first_block_no(sb, group);
 
-		ext4_debug("update backup group %#04llx (+%d)\n", block, bit);
+		/* Copy all of the GDT blocks into the backup in this group */
+		for (j = 0, block = start + 1; j < gdblocks; j++, block++) {
+			struct buffer_head *gdb;
+
+			ext4_debug("update backup group %#04llx\n", block);
+			err = extend_or_restart_transaction(handle, 1);
+			if (err)
+				goto out;
+
+			gdb = sb_getblk(sb, block);
+			if (!gdb) {
+				err = -EIO;
+				goto out;
+			}
+
+			err = ext4_journal_get_write_access(handle, gdb);
+			if (err) {
+				brelse(gdb);
+				goto out;
+			}
+			memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
+			       gdb->b_size);
+			set_buffer_uptodate(gdb);
+
+			err = ext4_handle_dirty_metadata(handle, NULL, gdb);
+			if (unlikely(err)) {
+				brelse(gdb);
+				goto out;
+			}
+			brelse(gdb);
+		}
+
+		/* Zero out all of the reserved backup group descriptor
+		 * table blocks
+		 */
+		if (ext4_bg_has_super(sb, group)) {
+			err = sb_issue_zeroout(sb, gdblocks + start + 1,
+					reserved_gdb, GFP_NOFS);
+			if (err)
+				goto out;
+		}
+
+		/* Initialize group tables of the grop @group */
+		if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
+			goto handle_bb;
+
+		/* Zero out all of the inode table blocks */
+		block = group_data[i].inode_table;
+		ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
+			   block, sbi->s_itb_per_group);
+		err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
+				       GFP_NOFS);
+		if (err)
+			goto out;
+
+handle_bb:
+		if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
+			goto handle_ib;
+
+		/* Initialize block bitmap of the @group */
+		block = group_data[i].block_bitmap;
 		err = extend_or_restart_transaction(handle, 1);
 		if (err)
-			goto exit_journal;
+			goto out;
 
-		gdb = sb_getblk(sb, block);
-		if (!gdb) {
-			err = -EIO;
-			goto exit_journal;
+		bh = bclean(handle, sb, block);
+		if (IS_ERR(bh)) {
+			err = PTR_ERR(bh);
+			goto out;
 		}
-		if ((err = ext4_journal_get_write_access(handle, gdb))) {
-			brelse(gdb);
-			goto exit_journal;
+		if (ext4_bg_has_super(sb, group)) {
+			ext4_debug("mark backup superblock %#04llx (+0)\n",
+				   start);
+			ext4_set_bits(bh->b_data, 0, gdblocks + reserved_gdb +
+						     1);
 		}
-		memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, gdb->b_size);
-		set_buffer_uptodate(gdb);
-		err = ext4_handle_dirty_metadata(handle, NULL, gdb);
-		if (unlikely(err)) {
-			brelse(gdb);
-			goto exit_journal;
+		ext4_mark_bitmap_end(group_data[i].blocks_count,
+				     sb->s_blocksize * 8, bh->b_data);
+		err = ext4_handle_dirty_metadata(handle, NULL, bh);
+		if (err)
+			goto out;
+		brelse(bh);
+
+handle_ib:
+		if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
+			continue;
+
+		/* Initialize inode bitmap of the @group */
+		block = group_data[i].inode_bitmap;
+		err = extend_or_restart_transaction(handle, 1);
+		if (err)
+			goto out;
+		/* Mark unused entries in inode bitmap used */
+		bh = bclean(handle, sb, block);
+		if (IS_ERR(bh)) {
+			err = PTR_ERR(bh);
+			goto out;
 		}
-		brelse(gdb);
+
+		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
+				     sb->s_blocksize * 8, bh->b_data);
+		err = ext4_handle_dirty_metadata(handle, NULL, bh);
+		if (err)
+			goto out;
+		brelse(bh);
+	}
+	bh = NULL;
+
+	/* Mark group tables in block bitmap */
+	for (j = 0; j < GROUP_TABLE_COUNT; j++) {
+		count = group_table_count[j];
+		start = (&group_data[0].block_bitmap)[j];
+		block = start;
+		for (i = 1; i < flex_gd->count; i++) {
+			block += group_table_count[j];
+			if (block == (&group_data[i].block_bitmap)[j]) {
+				count += group_table_count[j];
+				continue;
+			}
+			err = set_flexbg_block_bitmap(sb, handle,
+						flex_gd, start, count);
+			if (err)
+				goto out;
+			count = group_table_count[j];
+			start = group_data[i].block_bitmap;
+			block = start;
+		}
+
+		if (count) {
+			err = set_flexbg_block_bitmap(sb, handle,
+						flex_gd, start, count);
+			if (err)
+				goto out;
+		}
 	}
 
-	/* Zero out all of the reserved backup group descriptor table blocks */
-	ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
-			block, sbi->s_itb_per_group);
-	err = sb_issue_zeroout(sb, gdblocks + start + 1, reserved_gdb,
-			       GFP_NOFS);
-	if (err)
-		goto exit_journal;
-
-	err = extend_or_restart_transaction(handle, 2);
-	if (err)
-		goto exit_journal;
-
-	bh = bclean(handle, sb, input->block_bitmap);
-	if (IS_ERR(bh)) {
-		err = PTR_ERR(bh);
-		goto exit_journal;
-	}
-
-	if (ext4_bg_has_super(sb, input->group)) {
-		ext4_debug("mark backup group tables %#04llx (+0)\n", start);
-		ext4_set_bits(bh->b_data, 0, gdblocks + reserved_gdb + 1);
-	}
-
-	ext4_debug("mark block bitmap %#04llx (+%llu)\n", input->block_bitmap,
-		   input->block_bitmap - start);
-	ext4_set_bit(input->block_bitmap - start, bh->b_data);
-	ext4_debug("mark inode bitmap %#04llx (+%llu)\n", input->inode_bitmap,
-		   input->inode_bitmap - start);
-	ext4_set_bit(input->inode_bitmap - start, bh->b_data);
-
-	/* Zero out all of the inode table blocks */
-	block = input->inode_table;
-	ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
-			block, sbi->s_itb_per_group);
-	err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group, GFP_NOFS);
-	if (err)
-		goto exit_bh;
-	ext4_set_bits(bh->b_data, input->inode_table - start,
-		      sbi->s_itb_per_group);
-
-
-	ext4_mark_bitmap_end(input->blocks_count, sb->s_blocksize * 8,
-			     bh->b_data);
-	err = ext4_handle_dirty_metadata(handle, NULL, bh);
-	if (unlikely(err)) {
-		ext4_std_error(sb, err);
-		goto exit_bh;
-	}
+out:
 	brelse(bh);
-	/* Mark unused entries in inode bitmap used */
-	ext4_debug("clear inode bitmap %#04llx (+%llu)\n",
-		   input->inode_bitmap, input->inode_bitmap - start);
-	if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
-		err = PTR_ERR(bh);
-		goto exit_journal;
-	}
-
-	ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
-			     bh->b_data);
-	err = ext4_handle_dirty_metadata(handle, NULL, bh);
-	if (unlikely(err))
-		ext4_std_error(sb, err);
-exit_bh:
-	brelse(bh);
-
-exit_journal:
-	if ((err2 = ext4_journal_stop(handle)) && !err)
+	err2 = ext4_journal_stop(handle);
+	if (err2 && !err)
 		err = err2;
 
 	return err;
···
  * groups in current filesystem that have BACKUPS, or -ve error code.
  */
 static int verify_reserved_gdb(struct super_block *sb,
+			       ext4_group_t end,
 			       struct buffer_head *primary)
 {
 	const ext4_fsblk_t blk = primary->b_blocknr;
-	const ext4_group_t end = EXT4_SB(sb)->s_groups_count;
 	unsigned three = 1;
 	unsigned five = 5;
 	unsigned seven = 7;
···
 	if (!gdb_bh)
 		return -EIO;
 
-	gdbackups = verify_reserved_gdb(sb, gdb_bh);
+	gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
 	if (gdbackups < 0) {
 		err = gdbackups;
 		goto exit_bh;
···
 			err = -EIO;
 			goto exit_bh;
 		}
-		if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
+		gdbackups = verify_reserved_gdb(sb, group, primary[res]);
+		if (gdbackups < 0) {
 			brelse(primary[res]);
 			err = gdbackups;
 			goto exit_bh;
···
 	}
 }
 
+/*
+ * ext4_add_new_descs() adds @count group descriptor of groups
+ * starting at @group
+ *
+ * @handle: journal handle
+ * @sb: super block
+ * @group: the group no. of the first group desc to be added
+ * @resize_inode: the resize inode
+ * @count: number of group descriptors to be added
+ */
+static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
+			      ext4_group_t group, struct inode *resize_inode,
+			      ext4_group_t count)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	struct buffer_head *gdb_bh;
+	int i, gdb_off, gdb_num, err = 0;
+
+	for (i = 0; i < count; i++, group++) {
+		int reserved_gdb = ext4_bg_has_super(sb, group) ?
+			le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
+
+		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
+		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
+
+		/*
+		 * We will only either add reserved group blocks to a backup group
+		 * or remove reserved blocks for the first group in a new group block.
+		 * Doing both would be mean more complex code, and sane people don't
+		 * use non-sparse filesystems anymore.  This is already checked above.
+		 */
+		if (gdb_off) {
+			gdb_bh = sbi->s_group_desc[gdb_num];
+			err = ext4_journal_get_write_access(handle, gdb_bh);
+
+			if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
+				err = reserve_backup_gdb(handle, resize_inode, group);
+		} else
+			err = add_new_gdb(handle, resize_inode, group);
+		if (err)
+			break;
+	}
+	return err;
+}
+
+/*
+ * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
+ */
+static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
+				struct ext4_new_flex_group_data *flex_gd)
+{
+	struct ext4_new_group_data	*group_data = flex_gd->groups;
+	struct ext4_group_desc		*gdp;
+	struct ext4_sb_info		*sbi = EXT4_SB(sb);
+	struct buffer_head		*gdb_bh;
+	ext4_group_t			group;
+	__u16				*bg_flags = flex_gd->bg_flags;
+	int				i, gdb_off, gdb_num, err = 0;
+	
+
+	for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
+		group = group_data->group;
+
+		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
+		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
+
+		/*
+		 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
+		 */
+		gdb_bh = sbi->s_group_desc[gdb_num];
+		/* Update group descriptor block for new group */
+		gdp = (struct ext4_group_desc *)((char *)gdb_bh->b_data +
+						 gdb_off * EXT4_DESC_SIZE(sb));
+
+		memset(gdp, 0, EXT4_DESC_SIZE(sb));
+		ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
+		ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
+		ext4_inode_table_set(sb, gdp, group_data->inode_table);
+		ext4_free_group_clusters_set(sb, gdp,
+					     EXT4_B2C(sbi, group_data->free_blocks_count));
+		ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
+		gdp->bg_flags = cpu_to_le16(*bg_flags);
+		gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
+
+		err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
+		if (unlikely(err)) {
+			ext4_std_error(sb, err);
+			break;
+		}
+
+		/*
+		 * We can allocate memory for mb_alloc based on the new group
+		 * descriptor
+		 */
+		err = ext4_mb_add_groupinfo(sb, group, gdp);
+		if (err)
+			break;
+	}
+	return err;
+}
+
+/*
+ * ext4_update_super() updates the super block so that the newly added
+ * groups can be seen by the filesystem.
+ *
+ * @sb: super block
+ * @flex_gd: new added groups
+ */
+static void ext4_update_super(struct super_block *sb,
+			     struct ext4_new_flex_group_data *flex_gd)
+{
+	ext4_fsblk_t blocks_count = 0;
+	ext4_fsblk_t free_blocks = 0;
+	ext4_fsblk_t reserved_blocks = 0;
+	struct ext4_new_group_data *group_data = flex_gd->groups;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	int i;
+
+	BUG_ON(flex_gd->count == 0 || group_data == NULL);
+	/*
+	 * Make the new blocks and inodes valid next.  We do this before
+	 * increasing the group count so that once the group is enabled,
+	 * all of its blocks and inodes are already valid.
+	 *
+	 * We always allocate group-by-group, then block-by-block or
+	 * inode-by-inode within a group, so enabling these
+	 * blocks/inodes before the group is live won't actually let us
+	 * allocate the new space yet.
+	 */
+	for (i = 0; i < flex_gd->count; i++) {
+		blocks_count += group_data[i].blocks_count;
+		free_blocks += group_data[i].free_blocks_count;
+	}
+
+	reserved_blocks = ext4_r_blocks_count(es) * 100;
+	do_div(reserved_blocks, ext4_blocks_count(es));
+	reserved_blocks *= blocks_count;
+	do_div(reserved_blocks, 100);
+
+	ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
+	le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
+		     flex_gd->count);
+
+	/*
+	 * We need to protect s_groups_count against other CPUs seeing
+	 * inconsistent state in the superblock.
+	 *
+	 * The precise rules we use are:
+	 *
+	 * * Writers must perform a smp_wmb() after updating all
+	 *   dependent data and before modifying the groups count
+	 *
+	 * * Readers must perform an smp_rmb() after reading the groups
+	 *   count and before reading any dependent data.
+	 *
+	 * NB. These rules can be relaxed when checking the group count
+	 * while freeing data, as we can only allocate from a block
+	 * group after serialising against the group count, and we can
+	 * only then free after serialising in turn against that
+	 * allocation.
+	 */
+	smp_wmb();
+
+	/* Update the global fs size fields */
+	sbi->s_groups_count += flex_gd->count;
+
+	/* Update the reserved block counts only once the new group is
+	 * active. */
+	ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
+				reserved_blocks);
+
+	/* Update the free space counts */
+	percpu_counter_add(&sbi->s_freeclusters_counter,
+			   EXT4_B2C(sbi, free_blocks));
+	percpu_counter_add(&sbi->s_freeinodes_counter,
+			   EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
+
+	if (EXT4_HAS_INCOMPAT_FEATURE(sb,
+				      EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
+	    sbi->s_log_groups_per_flex) {
+		ext4_group_t flex_group;
+		flex_group = ext4_flex_group(sbi, group_data[0].group);
+		atomic_add(EXT4_B2C(sbi, free_blocks),
+			   &sbi->s_flex_groups[flex_group].free_clusters);
+		atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
+			   &sbi->s_flex_groups[flex_group].free_inodes);
+	}
+
+	if (test_opt(sb, DEBUG))
+		printk(KERN_DEBUG "EXT4-fs: added group %u:"
+		       "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
+		       blocks_count, free_blocks, reserved_blocks);
+}
+
+/* Add a flex group to an fs. Ensure we handle all possible error conditions
+ * _before_ we start modifying the filesystem, because we cannot abort the
+ * transaction and not have it write the data to disk.
+ */
+static int ext4_flex_group_add(struct super_block *sb,
+			       struct inode *resize_inode,
+			       struct ext4_new_flex_group_data *flex_gd)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	ext4_fsblk_t o_blocks_count;
+	ext4_grpblk_t last;
+	ext4_group_t group;
+	handle_t *handle;
+	unsigned reserved_gdb;
+	int err = 0, err2 = 0, credit;
+
+	BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
+
+	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
+	o_blocks_count = ext4_blocks_count(es);
+	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
+	BUG_ON(last);
+
+	err = setup_new_flex_group_blocks(sb, flex_gd);
+	if (err)
+		goto exit;
+	/*
+	 * We will always be modifying at least the superblock and  GDT
+	 * block.  If we are adding a group past the last current GDT block,
+	 * we will also modify the inode and the dindirect block.  If we
+	 * are adding a group with superblock/GDT backups  we will also
+	 * modify each of the reserved GDT dindirect blocks.
+	 */
+	credit = flex_gd->count * 4 + reserved_gdb;
+	handle = ext4_journal_start_sb(sb, credit);
+	if (IS_ERR(handle)) {
+		err = PTR_ERR(handle);
+		goto exit;
+	}
+
+	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
+	if (err)
+		goto exit_journal;
+
+	group = flex_gd->groups[0].group;
+	BUG_ON(group != EXT4_SB(sb)->s_groups_count);
+	err = ext4_add_new_descs(handle, sb, group,
+				resize_inode, flex_gd->count);
+	if (err)
+		goto exit_journal;
+
+	err = ext4_setup_new_descs(handle, sb, flex_gd);
+	if (err)
+		goto exit_journal;
+
+	ext4_update_super(sb, flex_gd);
+
+	err = ext4_handle_dirty_super(handle, sb);
+
+exit_journal:
+	err2 = ext4_journal_stop(handle);
+	if (!err)
+		err = err2;
+
+	if (!err) {
+		int i;
+		update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
+			       sizeof(struct ext4_super_block));
+		for (i = 0; i < flex_gd->count; i++, group++) {
+			struct buffer_head *gdb_bh;
+			int gdb_num;
+			gdb_num = group / EXT4_BLOCKS_PER_GROUP(sb);
+			gdb_bh = sbi->s_group_desc[gdb_num];
+			update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
+				       gdb_bh->b_size);
+		}
+	}
+exit:
+	return err;
+}
+
+static int ext4_setup_next_flex_gd(struct super_block *sb,
+				    struct ext4_new_flex_group_data *flex_gd,
+				    ext4_fsblk_t n_blocks_count,
+				    unsigned long flexbg_size)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	struct ext4_new_group_data *group_data = flex_gd->groups;
+	ext4_fsblk_t o_blocks_count;
+	ext4_group_t n_group;
+	ext4_group_t group;
+	ext4_group_t last_group;
+	ext4_grpblk_t last;
+	ext4_grpblk_t blocks_per_group;
+	unsigned long i;
+
+	blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
+
+	o_blocks_count = ext4_blocks_count(es);
+
+	if (o_blocks_count == n_blocks_count)
+		return 0;
+
+	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
+	BUG_ON(last);
+	ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
+
+	last_group = group | (flexbg_size - 1);
+	if (last_group > n_group)
+		last_group = n_group;
+
+	flex_gd->count = last_group - group + 1;
+
+	for (i = 0; i < flex_gd->count; i++) {
+		int overhead;
+
+		group_data[i].group = group + i;
+		group_data[i].blocks_count = blocks_per_group;
+		overhead = ext4_bg_has_super(sb, group + i) ?
+			   (1 + ext4_bg_num_gdb(sb, group + i) +
+			    le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
+		group_data[i].free_blocks_count = blocks_per_group - overhead;
+		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+					       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+			flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
+					       EXT4_BG_INODE_UNINIT;
+		else
+			flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
+	}
+
+	if (last_group == n_group &&
+	    EXT4_HAS_RO_COMPAT_FEATURE(sb,
+				       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+		/* We need to initialize block bitmap of last group. */
+		flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
+
+	if ((last_group == n_group) && (last != blocks_per_group - 1)) {
+		group_data[i - 1].blocks_count = last + 1;
+		group_data[i - 1].free_blocks_count -= blocks_per_group-
+					last - 1;
+	}
+
+	return 1;
+}
+
 /* Add group descriptor data to an existing or new group descriptor block.
  * Ensure we handle all possible error conditions _before_ we start modifying
  * the filesystem, because we cannot abort the transaction and not have it
···
  */
 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
 {
+	struct ext4_new_flex_group_data flex_gd;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	struct ext4_super_block *es = sbi->s_es;
 	int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
 		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
-	struct buffer_head *primary = NULL;
-	struct ext4_group_desc *gdp;
 	struct inode *inode = NULL;
-	handle_t *handle;
 	int gdb_off, gdb_num;
-	int err, err2;
+	int err;
+	__u16 bg_flags = 0;
 
 	gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
 	gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
···
 	}
 
 
-	if ((err = verify_group_input(sb, input)))
-		goto exit_put;
-
-	if ((err = setup_new_group_blocks(sb, input)))
-		goto exit_put;
-
-	/*
-	 * We will always be modifying at least the superblock and a GDT
-	 * block.  If we are adding a group past the last current GDT block,
-	 * we will also modify the inode and the dindirect block.  If we
-	 * are adding a group with superblock/GDT backups  we will also
-	 * modify each of the reserved GDT dindirect blocks.
-	 */
-	handle = ext4_journal_start_sb(sb,
-				       ext4_bg_has_super(sb, input->group) ?
-				       3 + reserved_gdb : 4);
-	if (IS_ERR(handle)) {
-		err = PTR_ERR(handle);
-		goto exit_put;
-	}
-
-	if ((err = ext4_journal_get_write_access(handle, sbi->s_sbh)))
-		goto exit_journal;
-
-        /*
-         * We will only either add reserved group blocks to a backup group
-         * or remove reserved blocks for the first group in a new group block.
-         * Doing both would be mean more complex code, and sane people don't
-         * use non-sparse filesystems anymore.  This is already checked above.
-         */
-	if (gdb_off) {
-		primary = sbi->s_group_desc[gdb_num];
-		if ((err = ext4_journal_get_write_access(handle, primary)))
-			goto exit_journal;
-
-		if (reserved_gdb && ext4_bg_num_gdb(sb, input->group)) {
-			err = reserve_backup_gdb(handle, inode, input->group);
-			if (err)
-				goto exit_journal;
-		}
-	} else {
-		/*
-		 * Note that we can access new group descriptor block safely
-		 * only if add_new_gdb() succeeds.
-		 */
-		err = add_new_gdb(handle, inode, input->group);
-		if (err)
-			goto exit_journal;
-		primary = sbi->s_group_desc[gdb_num];
-	}
-
-        /*
-         * OK, now we've set up the new group.  Time to make it active.
-         *
-         * so we have to be safe wrt. concurrent accesses the group
-         * data.  So we need to be careful to set all of the relevant
-         * group descriptor data etc. *before* we enable the group.
-         *
-         * The key field here is sbi->s_groups_count: as long as
-         * that retains its old value, nobody is going to access the new
-         * group.
-         *
-         * So first we update all the descriptor metadata for the new
-         * group; then we update the total disk blocks count; then we
-         * update the groups count to enable the group; then finally we
-         * update the free space counts so that the system can start
-         * using the new disk blocks.
-         */
-
-	/* Update group descriptor block for new group */
-	gdp = (struct ext4_group_desc *)((char *)primary->b_data +
-					 gdb_off * EXT4_DESC_SIZE(sb));
-
-	memset(gdp, 0, EXT4_DESC_SIZE(sb));
-	ext4_block_bitmap_set(sb, gdp, input->block_bitmap); /* LV FIXME */
-	ext4_inode_bitmap_set(sb, gdp, input->inode_bitmap); /* LV FIXME */
-	ext4_inode_table_set(sb, gdp, input->inode_table); /* LV FIXME */
-	ext4_free_group_clusters_set(sb, gdp, input->free_blocks_count);
-	ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
-	gdp->bg_flags = cpu_to_le16(EXT4_BG_INODE_ZEROED);
-	gdp->bg_checksum = ext4_group_desc_csum(sbi, input->group, gdp);
-
-	/*
-	 * We can allocate memory for mb_alloc based on the new group
-	 * descriptor
-	 */
-	err = ext4_mb_add_groupinfo(sb, input->group, gdp);
+	err = verify_group_input(sb, input);
 	if (err)
-		goto exit_journal;
+		goto out;
 
-	/*
-	 * Make the new blocks and inodes valid next.  We do this before
-	 * increasing the group count so that once the group is enabled,
-	 * all of its blocks and inodes are already valid.
-	 *
-	 * We always allocate group-by-group, then block-by-block or
-	 * inode-by-inode within a group, so enabling these
-	 * blocks/inodes before the group is live won't actually let us
-	 * allocate the new space yet.
-	 */
-	ext4_blocks_count_set(es, ext4_blocks_count(es) +
-		input->blocks_count);
-	le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb));
-
-	/*
-	 * We need to protect s_groups_count against other CPUs seeing
-	 * inconsistent state in the superblock.
-	 *
-	 * The precise rules we use are:
-	 *
-	 * * Writers must perform a smp_wmb() after updating all dependent
-	 *   data and before modifying the groups count
-	 *
-	 * * Readers must perform an smp_rmb() after reading the groups count
-	 *   and before reading any dependent data.
-	 *
-	 * NB. These rules can be relaxed when checking the group count
-	 * while freeing data, as we can only allocate from a block
-	 * group after serialising against the group count, and we can
-	 * only then free after serialising in turn against that
-	 * allocation.
-	 */
-	smp_wmb();
-
-	/* Update the global fs size fields */
-	sbi->s_groups_count++;
-
-	err = ext4_handle_dirty_metadata(handle, NULL, primary);
-	if (unlikely(err)) {
-		ext4_std_error(sb, err);
-		goto exit_journal;
-	}
-
-	/* Update the reserved block counts only once the new group is
-	 * active. */
-	ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
-		input->reserved_blocks);
-
-	/* Update the free space counts */
-	percpu_counter_add(&sbi->s_freeclusters_counter,
-			   EXT4_B2C(sbi, input->free_blocks_count));
-	percpu_counter_add(&sbi->s_freeinodes_counter,
-			   EXT4_INODES_PER_GROUP(sb));
-
-	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
-	    sbi->s_log_groups_per_flex) {
-		ext4_group_t flex_group;
-		flex_group = ext4_flex_group(sbi, input->group);
-		atomic_add(EXT4_B2C(sbi, input->free_blocks_count),
-			   &sbi->s_flex_groups[flex_group].free_clusters);
-		atomic_add(EXT4_INODES_PER_GROUP(sb),
-			   &sbi->s_flex_groups[flex_group].free_inodes);
-	}
-
-	ext4_handle_dirty_super(handle, sb);
-
-exit_journal:
-	if ((err2 = ext4_journal_stop(handle)) && !err)
-		err = err2;
-	if (!err && primary) {
-		update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
-			       sizeof(struct ext4_super_block));
-		update_backups(sb, primary->b_blocknr, primary->b_data,
-			       primary->b_size);
-	}
-exit_put:
+	flex_gd.count = 1;
+	flex_gd.groups = input;
+	flex_gd.bg_flags = &bg_flags;
+	err = ext4_flex_group_add(sb, inode, &flex_gd);
+out:
 	iput(inode);
 	return err;
 } /* ext4_group_add */
+
+/*
+ * extend a group without checking assuming that checking has been done.
+ */
+static int ext4_group_extend_no_check(struct super_block *sb,
+				      ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
+{
+	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+	handle_t *handle;
+	int err = 0, err2;
+
+	/* We will update the superblock, one block bitmap, and
+	 * one group descriptor via ext4_group_add_blocks().
+	 */
+	handle = ext4_journal_start_sb(sb, 3);
+	if (IS_ERR(handle)) {
+		err = PTR_ERR(handle);
+		ext4_warning(sb, "error %d on journal start", err);
+		return err;
+	}
+
+	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
+	if (err) {
+		ext4_warning(sb, "error %d on journal write access", err);
+		goto errout;
+	}
+
+	ext4_blocks_count_set(es, o_blocks_count + add);
+	ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
+		   o_blocks_count + add);
+	/* We add the blocks to the bitmap and set the group need init bit */
+	err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
+	if (err)
+		goto errout;
+	ext4_handle_dirty_super(handle, sb);
+	ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
+		   o_blocks_count + add);
+errout:
+	err2 = ext4_journal_stop(handle);
+	if (err2 && !err)
+		err = err2;
+
+	if (!err) {
+		if (test_opt(sb, DEBUG))
+			printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
+			       "blocks\n", ext4_blocks_count(es));
+		update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es,
+			       sizeof(struct ext4_super_block));
+	}
+	return err;
+}
 
 /*
  * Extend the filesystem to the new number of blocks specified.  This entry
···
 	ext4_grpblk_t last;
 	ext4_grpblk_t add;
 	struct buffer_head *bh;
-	handle_t *handle;
-	int err, err2;
+	int err;
 	ext4_group_t group;
 
 	o_blocks_count = ext4_blocks_count(es);
···
 	}
 	brelse(bh);
 
-	/* We will update the superblock, one block bitmap, and
-	 * one group descriptor via ext4_free_blocks().
-	 */
-	handle = ext4_journal_start_sb(sb, 3);
-	if (IS_ERR(handle)) {
-		err = PTR_ERR(handle);
-		ext4_warning(sb, "error %d on journal start", err);
-		goto exit_put;
-	}
-
-	if ((err = ext4_journal_get_write_access(handle,
-						 EXT4_SB(sb)->s_sbh))) {
-		ext4_warning(sb, "error %d on journal write access", err);
-		ext4_journal_stop(handle);
-		goto exit_put;
-	}
-	ext4_blocks_count_set(es, o_blocks_count + add);
-	ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
-		   o_blocks_count + add);
-	/* We add the blocks to the bitmap and set the group need init bit */
-	err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
-	ext4_handle_dirty_super(handle, sb);
-	ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
-		   o_blocks_count + add);
-	err2 = ext4_journal_stop(handle);
-	if (!err && err2)
-		err = err2;
-
-	if (err)
-		goto exit_put;
-
-	if (test_opt(sb, DEBUG))
-		printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n",
-		       ext4_blocks_count(es));
-	update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es,
-		       sizeof(struct ext4_super_block));
-exit_put:
+	err = ext4_group_extend_no_check(sb, o_blocks_count, add);
 	return err;
 } /* ext4_group_extend */
+
+/*
+ * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
+ *
+ * @sb: super block of the fs to be resized
+ * @n_blocks_count: the number of blocks resides in the resized fs
+ */
+int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
+{
+	struct ext4_new_flex_group_data *flex_gd = NULL;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	struct buffer_head *bh;
+	struct inode *resize_inode;
+	ext4_fsblk_t o_blocks_count;
+	ext4_group_t o_group;
+	ext4_group_t n_group;
+	ext4_grpblk_t offset;
+	unsigned long n_desc_blocks;
+	unsigned long o_desc_blocks;
+	unsigned long desc_blocks;
+	int err = 0, flexbg_size = 1;
+
+	o_blocks_count = ext4_blocks_count(es);
+
+	if (test_opt(sb, DEBUG))
+		printk(KERN_DEBUG "EXT4-fs: resizing filesystem from %llu "
+		       "upto %llu blocks\n", o_blocks_count, n_blocks_count);
+
+	if (n_blocks_count < o_blocks_count) {
+		/* On-line shrinking not supported */
+		ext4_warning(sb, "can't shrink FS - resize aborted");
+		return -EINVAL;
+	}
+
+	if (n_blocks_count == o_blocks_count)
+		/* Nothing need to do */
+		return 0;
+
+	ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &offset);
+	ext4_get_group_no_and_offset(sb, o_blocks_count, &o_group, &offset);
+
+	n_desc_blocks = (n_group + EXT4_DESC_PER_BLOCK(sb)) /
+			EXT4_DESC_PER_BLOCK(sb);
+	o_desc_blocks = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
+			EXT4_DESC_PER_BLOCK(sb);
+	desc_blocks = n_desc_blocks - o_desc_blocks;
+
+	if (desc_blocks &&
+	    (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE) ||
+	     le16_to_cpu(es->s_reserved_gdt_blocks) < desc_blocks)) {
+		ext4_warning(sb, "No reserved GDT blocks, can't resize");
+		return -EPERM;
+	}
+
+	resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
+	if (IS_ERR(resize_inode)) {
+		ext4_warning(sb, "Error opening resize inode");
+		return PTR_ERR(resize_inode);
+	}
+
+	/* See if the device is actually as big as what was requested */
+	bh = sb_bread(sb, n_blocks_count - 1);
+	if (!bh) {
+		ext4_warning(sb, "can't read last block, resize aborted");
+		return -ENOSPC;
+	}
+	brelse(bh);
+
+	if (offset != 0) {
+		/* extend the last group */
+		ext4_grpblk_t add;
+		add = EXT4_BLOCKS_PER_GROUP(sb) - offset;
+		err = ext4_group_extend_no_check(sb, o_blocks_count, add);
+		if (err)
+			goto out;
+	}
+
+	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
+	    es->s_log_groups_per_flex)
+		flexbg_size = 1 << es->s_log_groups_per_flex;
+
+	o_blocks_count = ext4_blocks_count(es);
+	if (o_blocks_count == n_blocks_count)
+		goto out;
+
+	flex_gd = alloc_flex_gd(flexbg_size);
+	if (flex_gd == NULL) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	/* Add flex groups. Note that a regular group is a
+	 * flex group with 1 group.
+	 */
+	while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
+					      flexbg_size)) {
+		ext4_alloc_group_tables(sb, flex_gd, flexbg_size);
+		err = ext4_flex_group_add(sb, resize_inode, flex_gd);
+		if (unlikely(err))
+			break;
+	}
+
+out:
+	if (flex_gd)
+		free_flex_gd(flex_gd);
+
+	iput(resize_inode);
+	if (test_opt(sb, DEBUG))
+		printk(KERN_DEBUG "EXT4-fs: resized filesystem from %llu "
+		       "upto %llu blocks\n", o_blocks_count, n_blocks_count);
+	return err;
+}

fs/ext4/super.c

···
 	}
 	if (sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME) {
 		seq_printf(seq, ",max_batch_time=%u",
-			   (unsigned) sbi->s_min_batch_time);
+			   (unsigned) sbi->s_max_batch_time);
 	}
 
 	/*
···
 	struct ext4_group_desc *gdp = NULL;
 	ext4_group_t flex_group_count;
 	ext4_group_t flex_group;
-	int groups_per_flex = 0;
+	unsigned int groups_per_flex = 0;
 	size_t size;
 	int i;
 
 	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
-	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
-
-	if (groups_per_flex < 2) {
+	if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
 		sbi->s_log_groups_per_flex = 0;
 		return 1;
 	}
+	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
 
 	/* We allocate both existing and potentially added groups */
 	flex_group_count = ((sbi->s_groups_count + groups_per_flex - 1) +
···
 	 * of the filesystem.
 	 */
 	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
-                ext4_msg(sb, KERN_WARNING, "bad geometry: first data"
+		ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
 			 "block %u is beyond end of filesystem (%llu)",
 			 le32_to_cpu(es->s_first_data_block),
 			 ext4_blocks_count(es));

fs/ext4/xattr_security.c

···
 			      name, value, size, flags);
 }
 
-int ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
-		    void *fs_info)
+static int
+ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		void *fs_info)
 {
 	const struct xattr *xattr;
 	handle_t *handle = fs_info;

fs/jbd2/commit.c

···
 	jbd_debug(3, "JBD2: commit phase 1\n");
 
 	/*
+	 * Clear revoked flag to reflect there is no revoked buffers
+	 * in the next transaction which is going to be started.
+	 */
+	jbd2_clear_buffer_revoked_flags(journal);
+
+	/*
 	 * Switch to a new revoke table.
 	 */
 	jbd2_journal_switch_revoke_table(journal);

fs/jbd2/revoke.c

···
  *   overwriting the new data.  We don't even need to clear the revoke
  *   bit here.
  *
+ * We cache revoke status of a buffer in the current transaction in b_states
+ * bits.  As the name says, revokevalid flag indicates that the cached revoke
+ * status of a buffer is valid and we can rely on the cached status.
+ *
  * Revoke information on buffers is a tri-state value:
  *
  * RevokeValid clear:	no cached revoke status, need to look it up
···
 		}
 	}
 	return did_revoke;
+}
+
+/*
+ * journal_clear_revoked_flag clears revoked flag of buffers in
+ * revoke table to reflect there is no revoked buffers in the next
+ * transaction which is going to be started.
+ */
+void jbd2_clear_buffer_revoked_flags(journal_t *journal)
+{
+	struct jbd2_revoke_table_s *revoke = journal->j_revoke;
+	int i = 0;
+
+	for (i = 0; i < revoke->hash_size; i++) {
+		struct list_head *hash_list;
+		struct list_head *list_entry;
+		hash_list = &revoke->hash_table[i];
+
+		list_for_each(list_entry, hash_list) {
+			struct jbd2_revoke_record_s *record;
+			struct buffer_head *bh;
+			record = (struct jbd2_revoke_record_s *)list_entry;
+			bh = __find_get_block(journal->j_fs_dev,
+					      record->blocknr,
+					      journal->j_blocksize);
+			if (bh) {
+				clear_buffer_revoked(bh);
+				__brelse(bh);
+			}
+		}
+	}
 }
 
 /* journal_switch_revoke table select j_revoke for next transaction

fs/jbd2/transaction.c

···
 			break;
 
 		spin_lock(&transaction->t_handle_lock);
-		if (!atomic_read(&transaction->t_updates)) {
-			spin_unlock(&transaction->t_handle_lock);
-			break;
-		}
 		prepare_to_wait(&journal->j_wait_updates, &wait,
 				TASK_UNINTERRUPTIBLE);
+		if (!atomic_read(&transaction->t_updates)) {
+			spin_unlock(&transaction->t_handle_lock);
+			finish_wait(&journal->j_wait_updates, &wait);
+			break;
+		}
 		spin_unlock(&transaction->t_handle_lock);
 		write_unlock(&journal->j_state_lock);
 		schedule();

include/linux/jbd2.h

···
 extern int	jbd2_journal_test_revoke(journal_t *, unsigned long long, tid_t);
 extern void	jbd2_journal_clear_revoke(journal_t *);
 extern void	jbd2_journal_switch_revoke_table(journal_t *journal);
+extern void	jbd2_clear_buffer_revoked_flags(journal_t *journal);
 
 /*
  * The log thread user interface:

include/trace/events/ext4.h

···
 );
 
 TRACE_EVENT(ext4_mb_release_group_pa,
-	TP_PROTO(struct ext4_prealloc_space *pa),
+	TP_PROTO(struct super_block *sb, struct ext4_prealloc_space *pa),
 
-	TP_ARGS(pa),
+	TP_ARGS(sb, pa),
 
 	TP_STRUCT__entry(
 		__field(	dev_t,	dev			)
···
 	),
 
 	TP_fast_assign(
-		__entry->dev		= pa->pa_inode->i_sb->s_dev;
+		__entry->dev		= sb->s_dev;
 		__entry->pa_pstart	= pa->pa_pstart;
 		__entry->pa_len		= pa->pa_len;
 	),