The mke2fs(8) man page was updated in 4727c67dc2, but needs some more clear descriptions for extra_isize and metadta_csum features. The uninit_bg feature is supported by all ext4-capable kernels, and does have a slow e2fsck pass for newly-formatted filesystems, so remove the caveat. Signed-off-by: Andreas Dilger <adilger@xxxxxxxxx> --- misc/mke2fs.8.in | 36 ++++++++++++++++++++++-------------- 1 files changed, 22 insertions(+), 14 deletions(-) diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in index df244de..4486014 100644 --- a/misc/mke2fs.8.in +++ b/misc/mke2fs.8.in @@ -210,8 +210,8 @@ in earlier versions of .BR mke2fs . The .B \-R -option is still accepted for backwards compatibility. The -following extended options are supported: +option is still accepted for backwards compatibility, but is deprecated. +The following extended options are supported: .RS 1.2i .TP .BI mmp_update_interval= interval @@ -548,7 +548,7 @@ of e2fsprogs will not support file systems with this feature enabled. .TP .B bigalloc .br -This feature enables clustered allocation, so that the unit of +This feature enables clustered block allocation, so that the unit of allocation is a power of two number of blocks. That is, each bit in the what had traditionally been known as the block allocation bitmap now indicates whether a cluster is in use or not, where a cluster is by @@ -570,7 +570,7 @@ features be enabled. .TP .B dir_index .br -Use hashed b-trees to speed up lookups in large directories. +Use hashed b-trees to speed up name lookups in large directories. .TP .B dir_nlink .br @@ -590,8 +590,15 @@ historical/backwards compatibility reasons.) .TP .B extra_isize .br -This feature enables storage of nanosecond timestamps and creation -time, if the inode size is larger than 256 bytes or larger. +This feature reserves a specific amount of space in each inode for +extended metadata such as nanosecond timestamps and file creation time, +even if the current kernel does not current need to reserve this much +space. Without this feature, the kernel will reserve the amount of +space for features currently it currently needs, and the rest may be +consumed by extended attributes. + +For this feature to be useful the inode size must be 256 bytes in size +or larger. .TP .B ext_attr .br @@ -649,10 +656,16 @@ set this feature automatically when a file > 2GiB is created.) .\" .TP .\" .B metadata_csum .\" .br -.\" Filesystem supports metadata checksumming. This feature enables a -.\" superset of the functionality of the +.\" Filesystem supports metadata checksumming. This feature stores +.\" checksums for all of the filesystem metadata (superblock, group +.\" descriptor blocks, inode and block bitmaps, directories, and +.\" extent tree blocks). The checksum algorithm used for the metadata +.\" blocks is different than the one used for group descriptors with the .\" .B uninit_bg -.\" feature. +.\" feature, these two features are incompatible and +.\" .B metadata_csum +.\" will be used preferentially instead of +.\" .BR uninit_bg . .\" .br .\" .B Future feature, available in e2fsprogs 1.43-WIP .TP @@ -719,11 +732,6 @@ and keep a high watermark for the unused inodes in a filesystem, to reduce .BR e2fsck (8) time. The result is that it can speed up filesystem creation time noticeably (if lazy_itable_init is enabled). -.IP -This first e2fsck run after enabling this feature will take the -full time, but subsequent e2fsck runs will take only a fraction of the -original time, depending on how full the file system is. -It is only supported by the ext4 filesystem in recent Linux kernels. .RE .TP .B \-q -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
