Date:	Thu, 1 Sep 2011 10:36:13 +0200 (CEST)
From:	Lukas Czerner <lczerner@...hat.com>
To:	Lukas Czerner <lczerner@...hat.com>
cc:	linux-ext4@...r.kernel.org, tytso@....EDU
Subject: Re: [PATCH 1/2] resize2fs: Add support for lazy itable
 initialization

On Mon, 16 May 2011, Lukas Czerner wrote:

> On Wed, 16 Feb 2011, Lukas Czerner wrote:
> 
> > On Tue, 1 Feb 2011, Lukas Czerner wrote:
> > 
> > > Lazy inode table initialization speeds up file system resize operation
> > > because we can let the inode tables uninitialized. For some time now the
> > > mke2fs has similar option and now, when we have in-kernel lazyinit
> > > implementation we can add this feature to the resize2fs as well.
> > > 
> > > This commit adds extended options '-E' to the resize2fs code along with
> > > the first extended option lazy_itable_init=n. With lazy_itable_init
> > > extended option one can instruct resize2fs to skip inode table
> > > initialization to significantly speed-up file system resize. If the
> > > option is omitted and the file system supports lazy inode table
> > > initialization it defaults to 1.
> > 
> > ping
> 
> ping^2

ping^3

> 
> > 
> > > 
> > > Signed-off-by: Lukas Czerner <lczerner@...hat.com>
> > > ---
> > >  resize/main.c         |   68 +++++++++++++++++++++++++++++++-
> > >  resize/online.c       |    2 +-
> > >  resize/resize2fs.8.in |   20 +++++++++
> > >  resize/resize2fs.c    |  105 +++++++++++++++++++++++++++---------------------
> > >  resize/resize2fs.h    |    3 +-
> > >  5 files changed, 148 insertions(+), 50 deletions(-)
> > > 
> > > diff --git a/resize/main.c b/resize/main.c
> > > index 28a49ba..0f1a8db 100644
> > > --- a/resize/main.c
> > > +++ b/resize/main.c
> > > @@ -40,7 +40,8 @@ char *program_name, *device_name, *io_options;
> > >  static void usage (char *prog)
> > >  {
> > >  	fprintf (stderr, _("Usage: %s [-d debug_flags] [-f] [-F] [-M] [-P] "
> > > -			   "[-p] device [new_size]\n\n"), prog);
> > > +			   "[-p] [-E extended_options] device [new_size]\n\n"),
> > > +			   prog);
> > >  
> > >  	exit (1);
> > >  }
> > > @@ -146,6 +147,59 @@ static void determine_fs_stride(ext2_filsys fs)
> > >  #endif
> > >  }
> > >  
> > > +static void parse_extended_opts(int *flags, const char *opts)
> > > +{
> > > +	char	*buf, *token, *next, *p, *arg, *badopt = 0;
> > > +	int	len;
> > > +	int	r_usage = 0;
> > > +
> > > +	len = strlen(opts);
> > > +	buf = malloc(len+1);
> > > +	if (!buf) {
> > > +		fprintf(stderr,
> > > +			_("Couldn't allocate memory to parse options!\n"));
> > > +		exit(1);
> > > +	}
> > > +	strcpy(buf, opts);
> > > +	for (token = buf; token && *token; token = next) {
> > > +		p = strchr(token, ',');
> > > +		next = 0;
> > > +		if (p) {
> > > +			*p = 0;
> > > +			next = p+1;
> > > +		}
> > > +		arg = strchr(token, '=');
> > > +		if (arg) {
> > > +			*arg = 0;
> > > +			arg++;
> > > +		}
> > > +		if (!strcmp(token, "lazy_itable_init")) {
> > > +			int lazy;
> > > +			if (arg)
> > > +				lazy = strtoul(arg, &p, 0);
> > > +			else
> > > +				lazy = 1;
> > > +			if (lazy)
> > > +				*flags |= RESIZE_LAZY_ITABLE_INIT;
> > > +		} else {
> > > +			r_usage++;
> > > +			badopt = token;
> > > +		}
> > > +	}
> > > +	if (r_usage) {
> > > +		fprintf(stderr, _("\nBad option(s) specified: %s\n\n"
> > > +			"Extended options are separated by commas, "
> > > +			"and may take an argument which\n"
> > > +			"\tis set off by an equals ('=') sign.\n\n"
> > > +			"Valid extended options are:\n"
> > > +			"\tlazy_itable_init=<0 to disable, 1 to enable>\n\n"),
> > > +			badopt ? badopt : "");
> > > +		free(buf);
> > > +		exit(1);
> > > +	}
> > > +	free(buf);
> > > +}
> > > +
> > >  int main (int argc, char ** argv)
> > >  {
> > >  	errcode_t	retval;
> > > @@ -174,6 +228,7 @@ int main (int argc, char ** argv)
> > >  	long		sysval;
> > >  	int		len, mount_flags;
> > >  	char		*mtpt;
> > > +	char *		extended_opts = NULL;
> > >  
> > >  #ifdef ENABLE_NLS
> > >  	setlocale(LC_MESSAGES, "");
> > > @@ -189,7 +244,7 @@ int main (int argc, char ** argv)
> > >  	if (argc && *argv)
> > >  		program_name = *argv;
> > >  
> > > -	while ((c = getopt (argc, argv, "d:fFhMPpS:")) != EOF) {
> > > +	while ((c = getopt (argc, argv, "d:fFhMPpS:E:")) != EOF) {
> > >  		switch (c) {
> > >  		case 'h':
> > >  			usage(program_name);
> > > @@ -215,6 +270,9 @@ int main (int argc, char ** argv)
> > >  		case 'S':
> > >  			use_stride = atoi(optarg);
> > >  			break;
> > > +		case 'E':
> > > +			extended_opts = optarg;
> > > +			break;
> > >  		default:
> > >  			usage(program_name);
> > >  		}
> > > @@ -232,6 +290,12 @@ int main (int argc, char ** argv)
> > >  	if (io_options)
> > >  		*io_options++ = 0;
> > >  
> > > +	if (access("/sys/fs/ext4/features/lazy_itable_init", R_OK) == 0)
> > > +		flags |= RESIZE_LAZY_ITABLE_INIT;
> > > +
> > > +	if (extended_opts)
> > > +		parse_extended_opts(&flags, extended_opts);
> > > +
> > >  	/*
> > >  	 * Figure out whether or not the device is mounted, and if it is
> > >  	 * where it is mounted.
> > > diff --git a/resize/online.c b/resize/online.c
> > > index 1d8d4ec..7bc27b3 100644
> > > --- a/resize/online.c
> > > +++ b/resize/online.c
> > > @@ -104,7 +104,7 @@ errcode_t online_resize_fs(ext2_filsys fs, const char *mtpt,
> > >  	 * but at least it allows on-line resizing to function.
> > >  	 */
> > >  	new_fs->super->s_feature_incompat &= ~EXT4_FEATURE_INCOMPAT_FLEX_BG;
> > > -	retval = adjust_fs_info(new_fs, fs, 0, *new_size);
> > > +	retval = adjust_fs_info(new_fs, fs, 0, *new_size, 0);
> > >  	if (retval)
> > >  		return retval;
> > >  
> > > diff --git a/resize/resize2fs.8.in b/resize/resize2fs.8.in
> > > index e02345d..448265c 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 \-E
> > > +.I extended-options
> > > +]
> > >  .I device
> > >  [
> > >  .I size
> > > @@ -128,6 +132,22 @@ The
> > >  program will heuristically determine the RAID stride that was specified
> > >  when the filesystem was created.  This option allows the user to
> > >  explicitly specify a RAID stride setting to be used by resize2fs instead.
> > > +.TP
> > > +.B \-E \fIextended-options
> > > +Set extended options for the filesystem.  Extended options are comma
> > > +separated, and may take an argument using the equals ('=') sign.
> > > +The following extended options are supported:
> > > +.RS 1.2i
> > > +.TP
> > > +.B lazy_itable_init\fR[\fB= \fI<0 to disable, 1 to enable>\fR]
> > > +If enabled and the uninit_bg feature is enabled, the inode table will
> > > +not be fully initialized by
> > > +.BR resize2fs .
> > > +This speeds up filesystem
> > > +resize noticeably, but it requires the kernel to finish
> > > +initializing the filesystem in the background when the filesystem is
> > > +mounted.  If the option value is omitted, it defaults to 1 to
> > > +enable lazy inode table initialization.
> > >  .SH KNOWN BUGS
> > >  The minimum size of the filesystem as estimated by resize2fs may be
> > >  incorrect, especially for filesystems with 1k and 2k blocksizes.
> > > diff --git a/resize/resize2fs.c b/resize/resize2fs.c
> > > index 216a626..1101364 100644
> > > --- a/resize/resize2fs.c
> > > +++ b/resize/resize2fs.c
> > > @@ -41,7 +41,8 @@
> > >  #endif
> > >  
> > >  static void fix_uninit_block_bitmaps(ext2_filsys fs);
> > > -static errcode_t adjust_superblock(ext2_resize_t rfs, blk64_t new_size);
> > > +static errcode_t adjust_superblock(ext2_resize_t rfs, blk64_t new_size,
> > > +				   int flags);
> > >  static errcode_t blocks_to_move(ext2_resize_t rfs);
> > >  static errcode_t block_mover(ext2_resize_t rfs);
> > >  static errcode_t inode_scan_and_fix(ext2_resize_t rfs);
> > > @@ -102,7 +103,7 @@ errcode_t resize_fs(ext2_filsys fs, blk64_t *new_size, int flags,
> > >  	if (retval)
> > >  		goto errout;
> > >  
> > > -	retval = adjust_superblock(rfs, *new_size);
> > > +	retval = adjust_superblock(rfs, *new_size, flags);
> > >  	if (retval)
> > >  		goto errout;
> > >  
> > > @@ -288,7 +289,8 @@ static void free_gdp_blocks(ext2_filsys fs,
> > >   * filesystem.
> > >   */
> > >  errcode_t adjust_fs_info(ext2_filsys fs, ext2_filsys old_fs,
> > > -			 ext2fs_block_bitmap reserve_blocks, blk64_t new_size)
> > > +			 ext2fs_block_bitmap reserve_blocks, blk64_t new_size,
> > > +			 int flags)
> > >  {
> > >  	errcode_t	retval;
> > >  	blk64_t		overhead = 0;
> > > @@ -497,8 +499,12 @@ retry:
> > >  		adjblocks = 0;
> > >  
> > >  		ext2fs_bg_flags_zap(fs, i);
> > > -		if (csum_flag)
> > > +		if (csum_flag && (flags & RESIZE_LAZY_ITABLE_INIT))
> > > +			ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
> > > +		else if (csum_flag)
> > >  			ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT | EXT2_BG_INODE_ZEROED);
> > > +		else
> > > +			flags &= ~RESIZE_LAZY_ITABLE_INIT;
> > >  		if (i == fs->group_desc_count-1) {
> > >  			numblocks = (ext2fs_blocks_count(fs->super) -
> > >  				     fs->super->s_first_data_block) %
> > > @@ -562,18 +568,57 @@ errout:
> > >  	return (retval);
> > >  }
> > >  
> > > +static errcode_t write_inode_tables(ext2_resize_t rfs, ext2_filsys fs)
> > > +{
> > > +	unsigned long	i, max_group;
> > > +	errcode_t	retval;
> > > +	int		adj = 0;
> > > +
> > > +	memset(rfs->itable_buf, 0, fs->blocksize * fs->inode_blocks_per_group);
> > > +	adj = rfs->old_fs->group_desc_count;
> > > +	max_group = fs->group_desc_count - adj;
> > > +	if (rfs->progress) {
> > > +		retval = rfs->progress(rfs, E2_RSZ_EXTEND_ITABLE_PASS,
> > > +				       0, max_group);
> > > +		if (retval)
> > > +			goto out;
> > > +	}
> > > +
> > > +	for (i = rfs->old_fs->group_desc_count;
> > > +	     i < fs->group_desc_count; i++) {
> > > +		/*
> > > +		 * Write out the new inode table
> > > +		 */
> > > +		retval = io_channel_write_blk64(fs->io,
> > > +						ext2fs_inode_table_loc(fs, i),
> > > +						fs->inode_blocks_per_group,
> > > +						rfs->itable_buf);
> > > +		if (retval)
> > > +			break;
> > > +
> > > +		io_channel_flush(fs->io);
> > > +		if (rfs->progress) {
> > > +			retval = rfs->progress(rfs, E2_RSZ_EXTEND_ITABLE_PASS,
> > > +					       i - adj + 1, max_group);
> > > +			if (retval)
> > > +				break;
> > > +		}
> > > +	}
> > > +	io_channel_flush(fs->io);
> > > +out:
> > > +	return retval;
> > > +}
> > > +
> > > +
> > >  /*
> > >   * This routine adjusts the superblock and other data structures, both
> > >   * in disk as well as in memory...
> > >   */
> > > -static errcode_t adjust_superblock(ext2_resize_t rfs, blk64_t new_size)
> > > +static errcode_t adjust_superblock(ext2_resize_t rfs, blk64_t new_size,
> > > +				   int flags)
> > >  {
> > > -	ext2_filsys fs;
> > > -	int		adj = 0;
> > > +	ext2_filsys	fs;
> > >  	errcode_t	retval;
> > > -	blk64_t		group_block;
> > > -	unsigned long	i;
> > > -	unsigned long	max_group;
> > >  
> > >  	fs = rfs->new_fs;
> > >  	ext2fs_mark_super_dirty(fs);
> > > @@ -585,7 +630,8 @@ static errcode_t adjust_superblock(ext2_resize_t rfs, blk64_t new_size)
> > >  	if (retval)
> > >  		return retval;
> > >  
> > > -	retval = adjust_fs_info(fs, rfs->old_fs, rfs->reserve_blocks, new_size);
> > > +	retval = adjust_fs_info(fs, rfs->old_fs, rfs->reserve_blocks, new_size,
> > > +				flags);
> > >  	if (retval)
> > >  		goto errout;
> > >  
> > > @@ -626,41 +672,8 @@ static errcode_t adjust_superblock(ext2_resize_t rfs, blk64_t new_size)
> > >  	if (retval)
> > >  		goto errout;
> > >  
> > > -	memset(rfs->itable_buf, 0, fs->blocksize * fs->inode_blocks_per_group);
> > > -	group_block = fs->super->s_first_data_block +
> > > -		rfs->old_fs->group_desc_count * fs->super->s_blocks_per_group;
> > > -
> > > -	adj = rfs->old_fs->group_desc_count;
> > > -	max_group = fs->group_desc_count - adj;
> > > -	if (rfs->progress) {
> > > -		retval = rfs->progress(rfs, E2_RSZ_EXTEND_ITABLE_PASS,
> > > -				       0, max_group);
> > > -		if (retval)
> > > -			goto errout;
> > > -	}
> > > -	for (i = rfs->old_fs->group_desc_count;
> > > -	     i < fs->group_desc_count; i++) {
> > > -		/*
> > > -		 * Write out the new inode table
> > > -		 */
> > > -		retval = io_channel_write_blk64(fs->io,
> > > -						ext2fs_inode_table_loc(fs, i),
> > > -						fs->inode_blocks_per_group,
> > > -						rfs->itable_buf);
> > > -		if (retval) goto errout;
> > > -
> > > -		io_channel_flush(fs->io);
> > > -		if (rfs->progress) {
> > > -			retval = rfs->progress(rfs, E2_RSZ_EXTEND_ITABLE_PASS,
> > > -					       i - adj + 1, max_group);
> > > -			if (retval)
> > > -				goto errout;
> > > -		}
> > > -		group_block += fs->super->s_blocks_per_group;
> > > -	}
> > > -	io_channel_flush(fs->io);
> > > -	retval = 0;
> > > -
> > > +	if (!(flags & RESIZE_LAZY_ITABLE_INIT))
> > > +		retval = write_inode_tables(rfs, fs);
> > >  errout:
> > >  	return retval;
> > >  }
> > > diff --git a/resize/resize2fs.h b/resize/resize2fs.h
> > > index 2184759..a968071 100644
> > > --- a/resize/resize2fs.h
> > > +++ b/resize/resize2fs.h
> > > @@ -79,6 +79,7 @@ typedef struct ext2_sim_progress *ext2_sim_progmeter;
> > >  
> > >  #define RESIZE_PERCENT_COMPLETE		0x0100
> > >  #define RESIZE_VERBOSE			0x0200
> > > +#define RESIZE_LAZY_ITABLE_INIT		0x0400	/* Do not initialize inode tables*/
> > >  
> > >  /*
> > >   * The core state structure for the ext2 resizer
> > > @@ -129,7 +130,7 @@ extern errcode_t resize_fs(ext2_filsys fs, blk64_t *new_size, int flags,
> > >  
> > >  extern errcode_t adjust_fs_info(ext2_filsys fs, ext2_filsys old_fs,
> > >  				ext2fs_block_bitmap reserve_blocks,
> > > -				blk64_t new_size);
> > > +				blk64_t new_size, int flags);
> > >  extern blk64_t calculate_minimum_resize_size(ext2_filsys fs);
> > >  
> > >  
> > > 
> > 
> > 
> 
> 

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