[1/2,v3] e2fsprogs: Fix how we treat user-spcified filesystem size

mke2fs and resize2fs allows specifying filesystem size as a parameter,
former called as blocks-count. However it has been a little bit messy so
this commit fixes it mainly by updating man pages.

We can not specify filesystem size in blocks count without specifying
blocksize as well. It is because we need blocks count to determine
filesystem type, and we need filesystem type to determine blocksize. So
it should not be allowed, however due to compatibility reason it should
be still possible, so at least print warning message for now, so we can
easily restrict that later.

Filesystem size can be specified using units as suffixes. This was not
documented for mke2fs, so this commits adds proper documentation into
mke2fs man page.

For the sake of completeness add 'b' (filesystem blocks) unit.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
---
[v2]: do not spell units - mebibytes etc... - but rather use just abbrev.
[v3]: Change some phrasing in man pages, mainly with the help from Eric Sandeen
 lib/e2p/parse_num.c   |    9 +++++++++
 misc/mke2fs.8.in      |   37 +++++++++++++++++++++++++++++++------
 resize/resize2fs.8.in |   23 ++++++++---------------
 3 files changed, 48 insertions(+), 21 deletions(-)

On 5/20/11 10:36 AM, Lukas Czerner wrote:
> mke2fs and resize2fs allows specifying filesystem size as a parameter,
> former called as blocks-count. However it has been a little bit messy so
> this commit fixes it mainly by updating man pages.
> 
> We can not specify filesystem size in blocks count without specifying
> blocksize as well. It is because we need blocks count to determine
> filesystem type, and we need filesystem type to determine blocksize. So
> it should not be allowed, however due to compatibility reason it should
> be still possible, so at least print warning message for now, so we can
> easily restrict that later.
> 
> Filesystem size can be specified using units as suffixes. This was not
> documented for mke2fs, so this commits adds proper documentation into
> mke2fs man page.
> 
> For the sake of completeness add 'b' (filesystem blocks) unit.

Very minor notes below, that I'm sure Ted can probably fix up on the way in.

Reviewed-by: Eric Sandeen <sandeen@redhat.com>

> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> ---
> [v2]: do not spell units - mebibytes etc... - but rather use just abbrev.
> [v3]: Change some phrasing in man pages, mainly with the help from Eric Sandeen
>  lib/e2p/parse_num.c   |    9 +++++++++
>  misc/mke2fs.8.in      |   37 +++++++++++++++++++++++++++++++------
>  resize/resize2fs.8.in |   23 ++++++++---------------
>  3 files changed, 48 insertions(+), 21 deletions(-)
> 
> diff --git a/lib/e2p/parse_num.c b/lib/e2p/parse_num.c
> index 83a329a..2f1d09d 100644
> --- a/lib/e2p/parse_num.c
> +++ b/lib/e2p/parse_num.c
> @@ -10,6 +10,7 @@
>   */
>  
>  #include "e2p.h"
> +#include "../misc/nls-enable.h"
>  
>  #include <stdlib.h>
>  
> @@ -37,6 +38,14 @@ unsigned long long parse_num_blocks2(const char *arg, int log_block_size)
>  		num >>= (1+log_block_size);
>  		break;
>  	case '\0':
> +	case 'b':
> +		if (!log_block_size) {
> +			fprintf(stderr,
> +				_("Warning: You should not specify filesystem "
> +				"size without specifying block size '-b'. "
> +				"Will assume 1024 byte blocks!\n"
> +				));
> +		}
>  		break;
>  	default:
>  		return 0;
> diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in
> index 4a3b0c3..e685dfb 100644
> --- a/misc/mke2fs.8.in
> +++ b/misc/mke2fs.8.in
> @@ -108,7 +108,7 @@ mke2fs \- create an ext2/ext3/ext4 filesystem
>  ]
>  .I device
>  [
> -.I blocks-count
> +.I filesystem-size
>  ]
>  @JDEV@.sp
>  @JDEV@.B "mke2fs \-O journal_dev"
> @@ -136,7 +136,7 @@ mke2fs \- create an ext2/ext3/ext4 filesystem
>  @JDEV@]
>  @JDEV@.I external-journal
>  @JDEV@[
> -@JDEV@.I blocks-count
> +@JDEV@.I filesystem-size
>  @JDEV@]
>  .SH DESCRIPTION
>  .B mke2fs
> @@ -145,10 +145,35 @@ partition.
>  .I device
>  is the special file corresponding to the device (e.g
>  .IR /dev/hdXX ).
> -.I blocks-count
> -is the number of blocks on the device.  If omitted,
> -.B mke2fs
> -automagically figures the file system size.  If called as
> +.I filesystem-size
> +is the size of the filesystem you want to create. Optionally, the
> +.I filesystem-size
> +parameter may be suffixed by one of the following units

very minor nitpick, should probably be "unit designators" - maybe ted can consider that a typo and fix it on the way in :)

> +designators: 'b', 's', 'K', 'M', 'G', or 'T',
> +for filesytem blocks, 512 byte sectors, KiB (2^10 Bytes), MiB (2^20 Bytes),
> +GiB (2^30 Bytes), or TiB (2^40 Bytes) respectively, which are binary (power-of-2),
> +not decimal, units. If no units are specified, then the
> +.I filesystem-size
> +parameter shall specify the number of filesystem blocks.
> +Note that you should not specify
> +.I filesystem-size
> +in block units (or without any units at all) without also specifying block
> +size with the
> +.B \-b
> +option. This will be allowed for now due to compatibility reasons,
> +however it may be restricted in the future.
> +If block size is not specified on the commandline and filesystem-size
> +is specified in block units,
> +1024-byte blocks will be assumed for this purpose, regardless
> +of the filesystem blocksize ultimately chosen by mke2fs.
> +
> +The
> +.I filesystem-size
> +may never be larger than the size of the partition.
> +If the
> +.I filesystem-size
> +parameter is not specified, it will default to the size of the partition.
> +If called as
>  .B mkfs.ext3
>  a journal is created as if the
>  .B \-j
> diff --git a/resize/resize2fs.8.in b/resize/resize2fs.8.in
> index e02345d..2273641 100644
> --- a/resize/resize2fs.8.in
> +++ b/resize/resize2fs.8.in
> @@ -36,29 +36,22 @@ filesystems mounted using ext3 and ext4.).
>  The 
>  .I size
>  parameter specifies the requested new size of the filesystem.
> -If no units are specified, the units of the
> -.I size
> -parameter shall be the filesystem blocksize of the filesystem.
>  Optionally, the 
>  .I size
> -parameter may be suffixed by one of the following the units 
> -designators: 's', 'K', 'M', or 'G',
> -for 512 byte sectors, kilobytes, megabytes, or gigabytes, respectively.
> -The 
> +parameter may be suffixed by one of the following the units

by one of the following unit designators

> +designators: 'b', 's', 'K', 'M', 'G', or 'T',
> +for filesystem blocks, 512 byte sectors, KiB (2^10 Bytes), MiB (2^20 Bytes),
> +GiB (2^30 Bytes), or TiB (2^40 Bytes) respectively, which are binary (power-of-2),
> +not decimal, units.
> +If no units are specified, then the
> +.I size
> +parameter shall specify the number of filesystem blocks. The
>  .I size
>  of the filesystem may never be larger than the size of the partition.
>  If 
>  .I size
>  parameter is not specified, it will default to the size of the partition.
>  .PP
> -Note: when kilobytes is used above, I mean
> -.IR real ,
> -power-of-2 kilobytes, (i.e., 1024 bytes), which some politically correct
> -folks insist should be the stupid-sounding ``kibibytes''.  The same
> -holds true for megabytes, also sometimes known as ``mebibytes'', or
> -gigabytes, as the amazingly silly ``gibibytes''.  Makes you want to
> -gibber, doesn't it?
> -.PP
>  The
>  .B resize2fs
>  program does not manipulate the size of partitions.  If you wish to enlarge

--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

On Fri, May 20, 2011 at 05:36:47PM +0200, Lukas Czerner wrote:
> mke2fs and resize2fs allows specifying filesystem size as a parameter,
> former called as blocks-count. However it has been a little bit messy so
> this commit fixes it mainly by updating man pages.
> 
> We can not specify filesystem size in blocks count without specifying
> blocksize as well. It is because we need blocks count to determine
> filesystem type, and we need filesystem type to determine blocksize. So
> it should not be allowed, however due to compatibility reason it should
> be still possible, so at least print warning message for now, so we can
> easily restrict that later.
> 
> Filesystem size can be specified using units as suffixes. This was not
> documented for mke2fs, so this commits adds proper documentation into
> mke2fs man page.
> 
> For the sake of completeness add 'b' (filesystem blocks) unit.

I'd much rather fix this by documenting that without a suffix, it will
be interpreted as the number of blocks if -b is specified, and that if
-b is not specified, it will be interpreted as kilobytes (but that
this usage is deprecated).

> @@ -37,6 +38,14 @@ unsigned long long parse_num_blocks2(const char *arg, int log_block_size)
>  		num >>= (1+log_block_size);
>  		break;
>  	case '\0':
> +	case 'b':
> +		if (!log_block_size) {
> +			fprintf(stderr,
> +				_("Warning: You should not specify filesystem "
> +				"size without specifying block size '-b'. "
> +				"Will assume 1024 byte blocks!\n"
> +				));
> +		}
>  		break;
>  	default:
>  		return 0;

I'd much rather not add this, since there may be other programs using
parse_num_blocks2() that aren't mke2fs or tune2fs, where -b doesn't
make sense.

							- Ted
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html