Date:	Fri,  7 Aug 2015 12:51:20 +0200
From:	Jan Kara <jack@...e.com>
To:	linux-ext4@...r.kernel.org
Cc:	Ted Tso <tytso@....edu>,
	"Darrick J. Wong" <darrick.wong@...cle.com>,
	Jan Kara <jack@...e.com>
Subject: [PATCH 10/19] tune2fs: Implement setting and disabling of 64-bit feature

Currently resize2fs is used to toggle 64-bit feature. However tune2fs
should logically handle that as toggling any other feature. Since we
have now factored out block moving code from resize2fs it is relatively
easy to implement toggling of the feature within tune2fs.

For now we leave the same functionality also in resize2fs for testing.
Later we can make resize2fs call tune2fs for backward compatibility.

Signed-off-by: Jan Kara <jack@...e.com>
---
 misc/tune2fs.c | 367 +++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 345 insertions(+), 22 deletions(-)

diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index d2e8b20f64e2..d6bfad3374d1 100644
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -447,10 +447,327 @@ static void request_fsck_afterwards(ext2_filsys fs)
 		printf("%s", _("(and reboot afterwards!)\n"));
 }
 
-static void convert_64bit(ext2_filsys fs, int direction)
+static errcode_t fix_resize_inode(ext2_filsys fs)
 {
-	if (!direction)
-		return;
+	errcode_t retval;
+
+	if (!(fs->super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE))
+		return 0;
+
+	retval = ext2fs_wipe_resize_inode(fs);
+	if (retval)
+		return retval;
+
+	return ext2fs_create_resize_inode(fs);
+}
+
+/*
+ * Make blocks that are needed for new group metadata unused and write there
+ * new group descriptors
+ */
+static errcode_t move_bg_metadata(ext2_filsys fs, ext2_filsys new_fs)
+{
+	dgrp_t i;
+	blk64_t b, c, d, old_desc_blocks, new_desc_blocks, j;
+	ext2fs_block_bitmap old_map = NULL, new_map = NULL;
+	int old, new;
+	errcode_t retval;
+	int cluster_ratio;
+	int need_new_block = 0;
+
+	retval = ext2fs_allocate_block_bitmap(fs, "old map", &old_map);
+	if (retval)
+		goto out;
+
+	retval = ext2fs_allocate_block_bitmap(fs, "new map", &new_map);
+	if (retval)
+		goto out;
+
+	if (EXT2_HAS_INCOMPAT_FEATURE(fs->super,
+				      EXT2_FEATURE_INCOMPAT_META_BG)) {
+		old_desc_blocks = fs->super->s_first_meta_bg;
+		new_desc_blocks = new_fs->super->s_first_meta_bg;
+	} else {
+		old_desc_blocks = fs->desc_blocks +
+				  fs->super->s_reserved_gdt_blocks;
+		new_desc_blocks = new_fs->desc_blocks +
+				  new_fs->super->s_reserved_gdt_blocks;
+	}
+
+	/* Construct bitmaps of super/descriptor blocks in old and new fs */
+	for (i = 0; i < fs->group_desc_count; i++) {
+		retval = ext2fs_super_and_bgd_loc2(fs, i, &b, &c, &d, NULL);
+		if (retval)
+			goto out;
+		if (b)
+			ext2fs_mark_block_bitmap2(old_map, b);
+		for (j = 0; c != 0 && j < old_desc_blocks; j++)
+			ext2fs_mark_block_bitmap2(old_map, c + j);
+		if (d)
+			ext2fs_mark_block_bitmap2(old_map, d);
+
+		retval = ext2fs_super_and_bgd_loc2(new_fs, i, &b, &c, &d, NULL);
+		if (retval)
+			goto out;
+		if (b)
+			ext2fs_mark_block_bitmap2(new_map, b);
+		for (j = 0; c != 0 && j < new_desc_blocks; j++)
+			ext2fs_mark_block_bitmap2(new_map, c + j);
+		if (d)
+			ext2fs_mark_block_bitmap2(new_map, d);
+	}
+
+	cluster_ratio = EXT2FS_CLUSTER_RATIO(new_fs);
+
+	/* Find changes in block allocations for bg metadata */
+	for (b = EXT2FS_B2C(fs, fs->super->s_first_data_block);
+	     b < ext2fs_blocks_count(new_fs->super);
+	     b += cluster_ratio) {
+		old = ext2fs_test_block_bitmap2(old_map, b);
+		new = ext2fs_test_block_bitmap2(new_map, b);
+
+		if (old && !new) {
+			/* mark old_map, unmark new_map */
+			if (cluster_ratio == 1)
+				ext2fs_block_alloc_stats2(new_fs, b, -1);
+		} else if (!old && new)
+			need_new_block = 1; /* unmark old_map, mark new_map */
+		else {
+			ext2fs_unmark_block_bitmap2(old_map, b);
+			ext2fs_unmark_block_bitmap2(new_map, b);
+		}
+	}
+
+	/*
+	 * new_map now shows blocks that have been newly allocated.
+	 * old_map now shows blocks that have been newly freed.
+	 */
+
+	if (need_new_block) {
+		/*
+		 * Now relocate metadata & data conflicting with new descriptor
+		 * blocks
+		 */
+		retval = ext2fs_move_blocks(new_fs, new_map, old_map);
+		if (retval)
+			goto out;
+
+		/* Now mark blocks for new group descriptors as used */
+		for (b = 0; b < ext2fs_blocks_count(new_fs->super);
+		     b += cluster_ratio) {
+			if (ext2fs_test_block_bitmap2(new_map, b) &&
+			    !ext2fs_test_block_bitmap2(new_fs->block_map, b))
+				ext2fs_block_alloc_stats2(new_fs, b, +1);
+		}
+	}
+
+	if (cluster_ratio > 1) {
+		/* Free unused clusters */
+		for (b = 0; b < ext2fs_blocks_count(new_fs->super);
+		     b += cluster_ratio)
+			if (ext2fs_test_block_bitmap2(old_map, b))
+				ext2fs_block_alloc_stats2(new_fs, b, -1);
+	}
+
+	/* Now update resize inode */
+	retval = fix_resize_inode(new_fs);
+out:
+	if (old_map)
+		ext2fs_free_block_bitmap(old_map);
+	if (new_map)
+		ext2fs_free_block_bitmap(new_map);
+	return retval;
+}
+
+
+/* Toggle 64bit mode */
+static errcode_t resize_group_descriptors(ext2_filsys *fs_p, int direction)
+{
+	void *o, *n, *new_group_desc;
+	dgrp_t i;
+	int copy_size;
+	errcode_t retval;
+	ext2_filsys new_fs = NULL;
+	ext2_filsys fs = *fs_p;
+
+	retval = ext2fs_dup_handle(fs, &new_fs);
+	if (retval)
+		return retval;
+
+	if (direction < 0) {
+		new_fs->super->s_feature_incompat &=
+					~EXT4_FEATURE_INCOMPAT_64BIT;
+		new_fs->super->s_desc_size = EXT2_MIN_DESC_SIZE;
+	} else {
+		new_fs->super->s_feature_incompat |=
+					EXT4_FEATURE_INCOMPAT_64BIT;
+		new_fs->super->s_desc_size = EXT2_MIN_DESC_SIZE_64BIT;
+	}
+
+	o = new_fs->group_desc;
+	new_fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
+			EXT2_DESC_PER_BLOCK(new_fs->super));
+	retval = ext2fs_get_arrayzero(new_fs->desc_blocks,
+				      fs->blocksize, &new_group_desc);
+	if (retval)
+		goto out;
+
+	n = new_group_desc;
+
+	if (EXT2_DESC_SIZE(fs->super) <= EXT2_DESC_SIZE(new_fs->super))
+		copy_size = EXT2_DESC_SIZE(fs->super);
+	else
+		copy_size = EXT2_DESC_SIZE(new_fs->super);
+	for (i = 0; i < fs->group_desc_count; i++) {
+		memcpy(n, o, copy_size);
+		n += EXT2_DESC_SIZE(new_fs->super);
+		o += EXT2_DESC_SIZE(fs->super);
+	}
+
+	ext2fs_free_mem(&new_fs->group_desc);
+	new_fs->group_desc = new_group_desc;
+
+	for (i = 0; i < fs->group_desc_count; i++)
+		ext2fs_group_desc_csum_set(new_fs, i);
+
+	/*
+	 * Update number of reserved blocks so that we need to alloc / free as
+	 * few blocks as possible
+	 */
+	if ((fs->super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE) &&
+	    (fs->desc_blocks != new_fs->desc_blocks)) {
+		int new;
+
+		new = ((int) new_fs->super->s_reserved_gdt_blocks) +
+			(fs->desc_blocks - new_fs->desc_blocks);
+		if (new < 0)
+			new = 0;
+		if (new > (int) fs->blocksize / 4)
+			new = fs->blocksize / 4;
+		new_fs->super->s_reserved_gdt_blocks = new;
+	}
+
+	retval = move_bg_metadata(fs, new_fs);
+
+	/* Return the modified filesystem */
+	new_fs->flags &= ~EXT2_FLAG_SUPER_ONLY;
+	ext2fs_mark_super_dirty(new_fs);
+	ext2fs_free(fs);
+	*fs_p = new_fs;
+	new_fs = NULL;
+out:
+	if (new_fs)
+		ext2fs_free(new_fs);
+	return retval;
+}
+
+/* Zero out the high bits of extent fields */
+static errcode_t zero_high_bits_in_extents(ext2_filsys fs, ext2_ino_t ino,
+					   struct ext2_inode *inode)
+{
+	ext2_extent_handle_t	handle;
+	struct ext2fs_extent	extent;
+	int			op = EXT2_EXTENT_ROOT;
+	errcode_t		errcode;
+
+	if (!(inode->i_flags & EXT4_EXTENTS_FL))
+		return 0;
+
+	errcode = ext2fs_extent_open(fs, ino, &handle);
+	if (errcode)
+		return errcode;
+
+	while (1) {
+		errcode = ext2fs_extent_get(handle, op, &extent);
+		if (errcode)
+			break;
+
+		op = EXT2_EXTENT_NEXT_SIB;
+
+		if (extent.e_pblk > (1ULL << 32)) {
+			extent.e_pblk &= (1ULL << 32) - 1;
+			errcode = ext2fs_extent_replace(handle, 0, &extent);
+			if (errcode)
+				break;
+		}
+	}
+
+	/* Ok if we run off the end */
+	if (errcode == EXT2_ET_EXTENT_NO_NEXT)
+		errcode = 0;
+	ext2fs_extent_free(handle);
+	return errcode;
+}
+
+/* Zero out the high bits of inodes. */
+static errcode_t zero_high_bits_in_inodes(ext2_filsys fs)
+{
+	int length = EXT2_INODE_SIZE(fs->super);
+	struct ext2_inode *inode = NULL;
+	ext2_inode_scan	scan = NULL;
+	errcode_t	retval;
+	ext2_ino_t	ino;
+
+	if (fs->super->s_creator_os != EXT2_OS_LINUX)
+		return 0;
+
+	retval = ext2fs_open_inode_scan(fs, 0, &scan);
+	if (retval)
+		return retval;
+
+	retval = ext2fs_get_mem(length, &inode);
+	if (retval)
+		goto out;
+
+	do {
+		retval = ext2fs_get_next_inode_full(scan, &ino, inode, length);
+		if (retval)
+			goto out;
+		if (!ino)
+			break;
+		if (!ext2fs_test_inode_bitmap2(fs->inode_map, ino))
+			continue;
+
+		/*
+		 * Here's how we deal with high block number fields:
+		 *
+		 *  - i_size_high has been been written out with i_size_lo
+		 *    since the ext2 days, so no conversion is needed.
+		 *
+		 *  - i_blocks_hi is guarded by both the huge_file feature and
+		 *    inode flags and has always been written out with
+		 *    i_blocks_lo if the feature is set.  The field is only
+		 *    ever read if both feature and inode flag are set, so
+		 *    we don't need to zero it now.
+		 *
+		 *  - i_file_acl_high can be uninitialized, so zero it if
+		 *    it isn't already.
+		 */
+		if (inode->osd2.linux2.l_i_file_acl_high) {
+			inode->osd2.linux2.l_i_file_acl_high = 0;
+			retval = ext2fs_write_inode_full(fs, ino, inode,
+							 length);
+			if (retval)
+				goto out;
+		}
+
+		retval = zero_high_bits_in_extents(fs, ino, inode);
+		if (retval)
+			goto out;
+	} while (ino);
+
+out:
+	if (inode)
+		ext2fs_free_mem(&inode);
+	if (scan)
+		ext2fs_close_inode_scan(scan);
+	return retval;
+}
+
+static errcode_t convert_64bit(ext2_filsys *fs_p, int direction)
+{
+	ext2_filsys fs = *fs_p;
+	errcode_t retval;
 
 	/*
 	 * Is resize2fs going to demand a fsck run? Might as well tell the
@@ -459,21 +776,25 @@ static void convert_64bit(ext2_filsys fs, int direction)
 	if (!fsck_requested &&
 	    ((fs->super->s_state & EXT2_ERROR_FS) ||
 	     !(fs->super->s_state & EXT2_VALID_FS) ||
-	     fs->super->s_lastcheck < fs->super->s_mtime))
+	     fs->super->s_lastcheck < fs->super->s_mtime)) {
 		request_fsck_afterwards(fs);
-	if (fsck_requested)
-		fprintf(stderr, _("After running e2fsck, please run `resize2fs %s %s"),
-			direction > 0 ? "-b" : "-s", fs->device_name);
-	else
-		fprintf(stderr, _("Please run `resize2fs %s %s"),
-			direction > 0 ? "-b" : "-s", fs->device_name);
+		return 0;
+	}
 
-	if (undo_file)
-		fprintf(stderr, _(" -z \"%s\""), undo_file);
-	if (direction > 0)
-		fprintf(stderr, _("' to enable 64-bit mode.\n"));
-	else
-		fprintf(stderr, _("' to disable 64-bit mode.\n"));
+	/*
+	 * Read bitmaps now since we are definitely going to need them and they
+	 * get properly duplicated when creating new fs handle in
+	 * resize_group_descriptors()
+	 */
+	retval = ext2fs_read_bitmaps(fs);
+	if (retval)
+		return retval;
+
+	retval = resize_group_descriptors(fs_p, direction);
+	if (retval)
+		return retval;
+
+	return zero_high_bits_in_inodes(*fs_p);
 }
 
 /* Rewrite extents */
@@ -1253,9 +1574,9 @@ mmp_error:
 	}
 
 	/*
-	 * We don't actually toggle 64bit; resize2fs does that.  But this
-	 * must come after the metadata_csum feature_on so that it won't
-	 * complain about the lack of 64bit.
+	 * Handle 64-bit conversion. We return the feature to the original
+	 * value for now until the conversion really takes place. Otherwise
+	 * some helper macros get confused.
 	 */
 	if (FEATURE_ON(E2P_FEATURE_INCOMPAT,
 		       EXT4_FEATURE_INCOMPAT_64BIT)) {
@@ -1264,8 +1585,8 @@ mmp_error:
 					  "while mounted!\n"));
 			exit(1);
 		}
-		sb->s_feature_incompat &= ~EXT4_FEATURE_INCOMPAT_64BIT;
 		feature_64bit = 1;
+		sb->s_feature_incompat &= ~EXT4_FEATURE_INCOMPAT_64BIT;
 	}
 	if (FEATURE_OFF(E2P_FEATURE_INCOMPAT,
 			EXT4_FEATURE_INCOMPAT_64BIT)) {
@@ -1274,8 +1595,8 @@ mmp_error:
 					  "while mounted!\n"));
 			exit(1);
 		}
-		sb->s_feature_incompat |= EXT4_FEATURE_INCOMPAT_64BIT;
 		feature_64bit = -1;
+		sb->s_feature_incompat |= EXT4_FEATURE_INCOMPAT_64BIT;
 	}
 
 	if (FEATURE_ON(E2P_FEATURE_RO_INCOMPAT,
@@ -3080,6 +3401,9 @@ retry_open:
 		}
 	}
 
+	if (feature_64bit)
+		convert_64bit(&fs, feature_64bit);
+
 	if (rewrite_checksums)
 		rewrite_metadata_checksums(fs);
 
@@ -3113,6 +3437,5 @@ closefs:
 		exit(1);
 	}
 
-	convert_64bit(fs, feature_64bit);
 	return (ext2fs_close_free(&fs) ? 1 : 0);
 }
-- 
2.1.4

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