From: Mingming Cao Subject: Re: [PATCH 3/8][e2fsprogs] add new -D option to mkfs Date: Thu, 30 Aug 2007 12:12:31 -0700 Message-ID: <1188501151.6594.32.camel@localhost.localdomain> References: <1188487715.15770.35.camel@ext1.frec.bull.fr> <1188488221.15770.46.camel@ext1.frec.bull.fr> Reply-To: cmm@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: linux-ext4 , "Theodore Ts'o" To: Valerie Clement Return-path: Received: from e2.ny.us.ibm.com ([32.97.182.142]:46215 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759135AbXH3TMS (ORCPT ); Thu, 30 Aug 2007 15:12:18 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e2.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id l7UJCGdr012983 for ; Thu, 30 Aug 2007 15:12:16 -0400 Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v8.5) with ESMTP id l7UJCGdd498910 for ; Thu, 30 Aug 2007 15:12:16 -0400 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l7UJCFg7016902 for ; Thu, 30 Aug 2007 15:12:16 -0400 In-Reply-To: <1188488221.15770.46.camel@ext1.frec.bull.fr> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, 2007-08-30 at 17:37 +0200, Valerie Clement wrote: > From: Valerie Clement > > This patch adds a new option -D to mkfs to allow creating > ext4 filesystems with larger group descriptor size. > > By default, the group descriptor size is 32 bytes. > To support 64-bit physical block numbers and thus to be able to use filesystems > > 16TB, the group descriptor size must be increased to 64 bytes. > Could you explain a bit more why we need this option? It seems to me we could make the block group descriptor size to 64bytes whenever creating a ext4 filesystem by default. Is there any case we need to create ext4 with old 32 bytes block group descriptors? > Use mkfs -t ext4 -D 64 to create an ext4 filesystem with 64-byte group > descriptor size. This set the EXT4_FEATURE_INCOMPAT_64BIT flag on device. > > The descriptor size is limited to a power-of-two value and to the block size. > > Signed-off-by: Valerie Clement > --- > > lib/ext2fs/ext2_fs.h | 7 +++++++ > lib/ext2fs/initialize.c | 1 + > misc/mke2fs.c | 33 +++++++++++++++++++++++++++++++-- > 3 files changed, 39 insertions(+), 2 deletions(-) > > diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h > index a316665..f6e8b36 100644 > --- a/lib/ext2fs/ext2_fs.h > +++ b/lib/ext2fs/ext2_fs.h > @@ -217,6 +217,13 @@ struct ext2_dx_countlimit { > /* > * Macro-instructions used to manage group descriptors > */ > +#define EXT2_MIN_DESC_SIZE 32 > +#define EXT2_MIN_DESC_SIZE_64BIT 64 > +#define EXT2_MAX_DESC_SIZE EXT2_MIN_BLOCK_SIZE > +#define EXT2_DESC_SIZE(s) \ > + ((EXT2_SB(s)->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT) ? \ > + (s)->s_desc_size : EXT2_MIN_DESC_SIZE) > + > #define EXT2_BLOCKS_PER_GROUP(s) (EXT2_SB(s)->s_blocks_per_group) > #define EXT2_INODES_PER_GROUP(s) (EXT2_SB(s)->s_inodes_per_group) > #define EXT2_INODES_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s)/EXT2_INODE_SIZE(s)) > diff --git a/lib/ext2fs/initialize.c b/lib/ext2fs/initialize.c > index 16e9eaa..ee7af93 100644 > --- a/lib/ext2fs/initialize.c > +++ b/lib/ext2fs/initialize.c > @@ -149,6 +149,7 @@ errcode_t ext2fs_initialize(const char *name, int flags, > > set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ > set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ > + set_field(s_desc_size, 0); > set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); > set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); > set_field(s_errors, EXT2_ERRORS_DEFAULT); > diff --git a/misc/mke2fs.c b/misc/mke2fs.c > index 4a6cace..115eef9 100644 > --- a/misc/mke2fs.c > +++ b/misc/mke2fs.c > @@ -96,7 +96,7 @@ static void usage(void) > { > fprintf(stderr, _("Usage: %s [-c|-t|-l filename] [-b block-size] " > "[-f fragment-size]\n\t[-i bytes-per-inode] [-I inode-size] " > - "[-j] [-J journal-options]\n" > + "[-D descriptor-size] [-j] [-J journal-options]\n" > "\t[-N number-of-inodes] [-m reserved-blocks-percentage] " > "[-o creator-os]\n\t[-g blocks-per-group] [-L volume-label] " > "[-M last-mounted-directory]\n\t[-O feature[,...]] " > @@ -911,6 +911,7 @@ static void PRS(int argc, char *argv[]) > int blocksize = 0; > int inode_ratio = 0; > int inode_size = 0; > + int desc_size = 0; > double reserved_ratio = 5.0; > int sector_size = 0; > int show_version_only = 0; > @@ -993,7 +994,7 @@ static void PRS(int argc, char *argv[]) > } > > while ((c = getopt (argc, argv, > - "b:cf:g:i:jl:m:no:qr:s:tvE:FI:J:L:M:N:O:R:ST:V")) != EOF) { > + "b:cf:g:i:jl:m:no:qr:s:tvD:E:FI:J:L:M:N:O:R:ST:V")) != EOF) { > switch (c) { > case 'b': > blocksize = strtol(optarg, &tmp, 0); > @@ -1110,6 +1111,14 @@ static void PRS(int argc, char *argv[]) > exit(1); > } > break; > + case 'D': > + desc_size = strtoul(optarg, &tmp, 0); > + if (*tmp) { > + com_err(program_name, 0, > + _("invalid descriptor size - %s"), optarg); > + exit(1); > + } > + break; > case 'v': > verbose = 1; > break; > @@ -1439,6 +1448,26 @@ static void PRS(int argc, char *argv[]) > } > } > > + if (desc_size) { > + if (desc_size < EXT2_MIN_DESC_SIZE || > + desc_size > EXT2_BLOCK_SIZE(&fs_param) || > + desc_size & (desc_size -1)) { > + com_err(program_name, 0, > + _("invalid descriptor size %d (min %d/max %d)"), > + desc_size, EXT2_MIN_DESC_SIZE, > + blocksize); > + exit(1); > + } > + if (desc_size != EXT2_MIN_DESC_SIZE) > + fprintf(stderr, _("Warning: %d-byte descriptors not " > + "usable on older systems\n"), > + desc_size); > + fs_param.s_desc_size = desc_size; > + if (desc_size > EXT2_MIN_DESC_SIZE) > + fs_param.s_feature_incompat |= EXT4_FEATURE_INCOMPAT_64BIT; > + } > + > + > if (!force && fs_param.s_blocks_count >= ((unsigned) 1 << 31)) { > com_err(program_name, 0, > _("Filesystem too large. No more than 2**31-1 blocks\n" > > > - > 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