On 12.03.2015 22:26, Darrick J. Wong wrote:

On Thu, Mar 12, 2015 at 07:20:13PM +0300, Konstantin Khlebnikov wrote:

quoted

Resize2fs relocates last inodes when it shinks filesystem.
This patch reuses this code for relocating first inodes,
it adds option '-I' for changing first normal inode.

Signed-off-by: Konstantin Khlebnikov <redacted>
---
  resize/main.c         |   38 ++++++++++++++++++++++++++++++++----
  resize/resize2fs.8.in |    8 ++++++++
  resize/resize2fs.c    |   52 +++++++++++++++++++++++++++++++++++++++++++++++--
  resize/resize2fs.h    |    3 +++
  4 files changed, 95 insertions(+), 6 deletions(-)

diff --git a/resize/main.c b/resize/main.c
index 16f48d438cb0..eae7146f41ab 100644
--- a/resize/main.c
+++ b/resize/main.c

-cut

quoted

@@ -507,6 +513,28 @@ int main (int argc, char ** argv)
  				"feature.\n"));
  			exit(1);
  		}
+	} else if (flags & RESIZE_SPECIAL_INODES) {
+		if (rfs->first_ino > fs->super->s_inodes_count) {

An FS with rfs->first_ino == fs->super->s_inodes_count isn't going to be
very useful... presumably you'd want at least one regular inode, right?

In this case there will be exactly one regular inode:
s_inodes_count is index of last inode on the filesystem.

quoted

+			fprintf(stderr, _("First inode too big\n"));

"Cannot reserve more than ($s_inodes_count - 1) inodes"?

So, you're suggest to rephrase option as "reserve special inodes"
instead of "set first normal inode"?

quoted

+			exit(1);
+		}
+		if (rfs->first_ino < EXT2_FIRST_INO(fs->super)) {
+			fprintf(stderr, _("The filesystem has %d special inodes."
+					  "Reducing isn't supported.\n\n"),
+					EXT2_FIRST_INO(fs->super));
+			exit(1);
+		}
+		if (rfs->first_ino == EXT2_FIRST_INO(fs->super)) {
+			fprintf(stderr, _("The filesystem already has %d "
+					  "special inodes. Nothing to do!\n\n"),
+					EXT2_FIRST_INO(fs->super));
+			exit(0);
+		}
+		if (mount_flags & EXT2_MF_MOUNTED) {
+			fprintf(stderr, _("Cannot change count of special "
+				"inodes while the filesystem is mounted.\n"));
+			exit(1);
+		}
  	} else if (new_size == ext2fs_blocks_count(fs->super)) {
  		fprintf(stderr, _("The filesystem is already %llu (%dk) "
  			"blocks long.  Nothing to do!\n\n"), new_size,

@@ -532,6 +560,8 @@ int main (int argc, char ** argv)
  			printf(_("Converting the filesystem to 64-bit.\n"));
  		else if (flags & RESIZE_DISABLE_64BIT)
  			printf(_("Converting the filesystem to 32-bit.\n"));
+		else if (flags & RESIZE_SPECIAL_INODES)
+			printf(_("Reserving special inodes.\n"));
  		else
  			printf(_("Resizing the filesystem on "
  				 "%s to %llu (%dk) blocks.\n"),

diff --git a/resize/resize2fs.8.in b/resize/resize2fs.8.in
index 0129bfcafa3b..f22563fe07e1 100644
--- a/resize/resize2fs.8.in
+++ b/resize/resize2fs.8.in

@@ -18,6 +18,10 @@ resize2fs \- ext2/ext3/ext4 file system resizer
  .B \-S
  .I RAID-stride
  ]
+[
+.B \-I
+.I first-inode
+]
  .I device
  [
  .I size

@@ -101,6 +105,10 @@ to resize the filesystem concurrent with changing the 64bit status.
  Turns on the 64bit feature, resizes the group descriptors as necessary, and
  moves other metadata out of the way.
  .TP
+.B \-I \fI <first-inode>
+This changes first normal inode and relocates inuse inodes into vacant slots.
+Inodes below that are reserved for internal use. Reducing isn't supported.

"Increases the number of reserved inodes, moving any in-use inodes into vacant
slots."?

--D

quoted

+.TP
  .B \-d \fIdebug-flags
  Turns on various resize2fs debugging features, if they have been compiled
  into the binary.

diff --git a/resize/resize2fs.c b/resize/resize2fs.c
index dead364bf4bf..2fb653b76dd8 100644
--- a/resize/resize2fs.c
+++ b/resize/resize2fs.c

@@ -48,6 +48,7 @@ static errcode_t block_mover(ext2_resize_t rfs);
  static errcode_t inode_scan_and_fix(ext2_resize_t rfs);
  static errcode_t inode_ref_fix(ext2_resize_t rfs);
  static errcode_t move_itables(ext2_resize_t rfs);
+static errcode_t zero_new_special_inodes(ext2_resize_t rfs);
  static errcode_t fix_resize_inode(ext2_filsys fs);
  static errcode_t ext2fs_calculate_summary_stats(ext2_filsys fs);
  static errcode_t fix_sb_journal_backup(ext2_filsys fs);

@@ -112,6 +113,11 @@ errcode_t resize_fs(ext2_filsys fs, ext2_resize_t rfs)
  	if (retval)
  		goto errout;

+	if (flags & RESIZE_SPECIAL_INODES) {
+		ext2fs_update_dynamic_rev(rfs->new_fs);
+		EXT2_SB(rfs->new_fs->super)->s_first_ino = rfs->first_ino;
+	}
+
  	init_resource_track(&rtrack, "resize_group_descriptors", fs->io);
  	retval = resize_group_descriptors(rfs);
  	if (retval)

@@ -177,6 +183,12 @@ errcode_t resize_fs(ext2_filsys fs, ext2_resize_t rfs)
  		goto errout;
  	print_resource_track(rfs, &rtrack, fs->io);

+	init_resource_track(&rtrack, "zero_new_special_inodes", fs->io);
+	retval = zero_new_special_inodes(rfs);
+	if (retval)
+		goto errout;
+	print_resource_track(rfs, &rtrack, fs->io);
+
  	init_resource_track(&rtrack, "move_itables", fs->io);
  	retval = move_itables(rfs);
  	if (retval)

@@ -1963,7 +1975,8 @@ static errcode_t inode_scan_and_fix(ext2_resize_t rfs)

  	if ((rfs->old_fs->group_desc_count <=
  	     rfs->new_fs->group_desc_count) &&
-	    !rfs->bmap)
+	    !rfs->bmap &&
+	    !(rfs->flags & RESIZE_SPECIAL_INODES))
  		return 0;

  	set_com_err_hook(quiet_com_err_proc);

@@ -2018,7 +2031,11 @@ static errcode_t inode_scan_and_fix(ext2_resize_t rfs)
  			goto errout;

  		new_inode = ino;
-		if (ino <= start_to_move)
+		if (ino >= EXT2_FIRST_INO(rfs->old_fs->super) &&
+		    ino <  EXT2_FIRST_INO(rfs->new_fs->super)) {
+			ext2fs_inode_alloc_stats2(rfs->new_fs, ino, -1,
+						  pb.is_dir);
+		} else if (ino <= start_to_move)
  			goto remap_blocks; /* Don't need to move inode. */

  		/*

@@ -2552,6 +2569,37 @@ static errcode_t reserve_sparse_super2_last_group(ext2_resize_t rfs,
  }

  /*
+ * Clear new special inodes
+ */
+static errcode_t zero_new_special_inodes(ext2_resize_t rfs)
+{
+	ext2_filsys		fs = rfs->new_fs;
+	int			inode_size;
+	struct ext2_inode	*inode;
+	errcode_t		retval;
+	ext2_ino_t		ino;
+
+	if (!(rfs->flags & RESIZE_SPECIAL_INODES))
+		return 0;
+
+	inode_size = EXT2_INODE_SIZE(fs->super);
+	retval = ext2fs_get_memzero(inode_size, &inode);
+	if (retval)
+		return retval;
+
+	for (ino = EXT2_FIRST_INO(rfs->old_fs->super);
+	     ino < EXT2_FIRST_INO(fs->super); ino++) {
+		/* All special inodes are marked as inuse */
+		ext2fs_inode_alloc_stats2(fs, ino, +1, 0);
+		retval = ext2fs_write_inode_full(fs, ino, inode, inode_size);
+		if (retval)
+			break;
+	}
+	ext2fs_free_mem(&inode);
+	return retval;
+}
+
+/*
   * Fix the resize inode
   */
  static errcode_t fix_resize_inode(ext2_filsys fs)

diff --git a/resize/resize2fs.h b/resize/resize2fs.h
index c5377e2b06c3..84f83b09f237 100644
--- a/resize/resize2fs.h
+++ b/resize/resize2fs.h

@@ -85,6 +85,8 @@ typedef struct ext2_sim_progress *ext2_sim_progmeter;
  #define RESIZE_ENABLE_64BIT		0x0400
  #define RESIZE_DISABLE_64BIT		0x0800

+#define RESIZE_SPECIAL_INODES		0x1000
+
  /*
   * This structure is used for keeping track of how much resources have
   * been used for a particular resize2fs pass.

@@ -130,6 +132,7 @@ struct ext2_resize_struct {
  	void		*prog_data;

  	blk64_t		new_size;
+	ext2_ino_t	first_ino;
  };

  /*

--

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-- 
Konstantin