From: "Darrick J. Wong" <darrick.wong@oracle.com>
Subject: Re: [PATCH 11/19] mke2fs: Allow specifying number of reserved inodes
Date: Fri, 7 Aug 2015 08:37:22 -0700
Message-ID: <20150807153722.GB24988@birch.djwong.org>
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Cc: linux-ext4@vger.kernel.org, Ted Tso <tytso@mit.edu>,
	Jan Kara <jack@suse.cz>
To: Jan Kara <jack@suse.com>
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On Fri, Aug 07, 2015 at 12:51:21PM +0200, Jan Kara wrote:
> From: Jan Kara <jack@suse.cz>
> 
> Add option to specify number of reserved inodes in the created
> filesystem.
> 
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
>  misc/mke2fs.8.in      |  6 ++++++
>  misc/mke2fs.c         | 40 +++++++++++++++++++++++++++++++++++++++-
>  misc/mke2fs.conf.5.in |  6 ++++++
>  3 files changed, 51 insertions(+), 1 deletion(-)
> 
> diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in
> index 40c40d3ed065..520a07185f9f 100644
> --- a/misc/mke2fs.8.in
> +++ b/misc/mke2fs.8.in
> @@ -384,6 +384,12 @@ Do not attempt to discard blocks at mkfs time.
>  @QUOTA_MAN_COMMENT@.B quota
>  @QUOTA_MAN_COMMENT@feature is set. Without this extended option, the default
>  @QUOTA_MAN_COMMENT@behavior is to initialize both user and group quotas.
> +.TP
> +.BI reserved_inodes= number
> +Specify the number of inodes reserved for system files. This number must be
> +at least 10. Currently 10 is enough but future features may require additional
> +reserved inodes. Reserving more inodes after file system is created requires
> +full file system scan so it can take a long time.

Perhaps:

"...requires a full file system scan, which can take a long time."

The "it" in "it can take" could be confused as referring to the process of
reserving more inodes (vs. moving inodes around after creation, which is what
takes a long time).

Same comment applies to the manpage at the bottom of the patch.

--D

>  .RE
>  .TP
>  .BI \-f " fragment-size"
> diff --git a/misc/mke2fs.c b/misc/mke2fs.c
> index 78b1252d8519..d61d1a332e67 100644
> --- a/misc/mke2fs.c
> +++ b/misc/mke2fs.c
> @@ -1024,6 +1024,34 @@ static void parse_extended_opts(struct ext2_super_block *param,
>  				r_usage++;
>  				continue;
>  			}
> +		} else if (!strcmp(token, "reserved_inodes")) {
> +			unsigned int reserved_inodes;
> +
> +			if (!arg) {
> +				r_usage++;
> +				badopt = token;
> +				continue;
> +			}
> +			reserved_inodes = strtoul(arg, &p, 0);
> +			if (*p) {
> +				fprintf(stderr,
> +					_("Invalid number of reserved inodes "
> +					  "%s\n"),
> +					arg);
> +				r_usage++;
> +				continue;
> +			}
> +			/* Ino 0 is invalid so bump by 1... */
> +			reserved_inodes++;
> +			if (reserved_inodes < EXT2_GOOD_OLD_FIRST_INO) {
> +				fprintf(stderr,
> +					_("Too few reserved inodes "
> +					  "%s (must be at least %u)\n"),
> +					arg, EXT2_GOOD_OLD_FIRST_INO - 1);
> +				r_usage++;
> +				continue;
> +			}
> +			param->s_first_ino = reserved_inodes;
>  		} else {
>  			r_usage++;
>  			badopt = token;
> @@ -1049,7 +1077,8 @@ static void parse_extended_opts(struct ext2_super_block *param,
>  			"\ttest_fs\n"
>  			"\tdiscard\n"
>  			"\tnodiscard\n"
> -			"\tquotatype=<usr OR grp>\n\n"),
> +			"\tquotatype=<usr OR grp>\n"
> +			"\treserved_inodes=<number of reserved inodes>\n\n"),
>  			badopt ? badopt : "");
>  		free(buf);
>  		exit(1);
> @@ -2422,6 +2451,15 @@ profile_error:
>  		exit(1);
>  	}
>  
> +	/* Count with one more inode for lost+found */
> +	if (fs_param.s_first_ino >= fs_param.s_inodes_count + 1) {
> +		com_err(program_name, 0, _("asked for more reserved inodes than filesystem has "
> +			"available (%u >= %u)\n"),
> +			(unsigned int)fs_param.s_first_ino,
> +			(unsigned int)fs_param.s_inodes_count + 1);
> +		exit(1);
> +	}
> +
>  	/*
>  	 * Calculate number of blocks to reserve
>  	 */
> diff --git a/misc/mke2fs.conf.5.in b/misc/mke2fs.conf.5.in
> index ad6c11b3cb7b..06ca9e4eabc4 100644
> --- a/misc/mke2fs.conf.5.in
> +++ b/misc/mke2fs.conf.5.in
> @@ -195,6 +195,12 @@ specify one on the command line, and the filesystem-type
>  specific section of the configuration file does not specify a default
>  reserved ratio. This value can be a floating point number.
>  .TP
> +.I reserved_inodes
> +This relation specifies the default number of inodes reserved for system files.
> +The number must be at least 10. Currently 10 is enough but future features may
> +require additional reserved inodes. Reserving more inodes after file system is
> +created requires full file system scan so it can take a long time.
> +.TP
>  .I undo_dir
>  This relation specifies the directory where the undo file should be
>  stored.  It can be overridden via the
> -- 
> 2.1.4
>