From: Robin Dong <sanbai@xxxxxxxxxx> add manual for tool 'mksparse'. Reviewed-by: Coly Li <bosong.ly@xxxxxxxxxx> Signed-off-by: Robing Dong <sanbai@xxxxxxxxxx> --- misc/Makefile.in | 5 +++ misc/mksparse.8.in | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 91 insertions(+), 0 deletions(-) create mode 100644 misc/mksparse.8.in diff --git a/misc/Makefile.in b/misc/Makefile.in index fcd316e..acea909 100644 --- a/misc/Makefile.in +++ b/misc/Makefile.in @@ -18,6 +18,7 @@ INSTALL = @INSTALL@ @IMAGER_CMT@E2IMAGE_MAN= e2image.8 @IMAGER_CMT@MKSPARSE_PROG= mksparse +@IMAGER_CMT@MKSPARSE_MAN= mksparse.8 @UUIDD_CMT@UUIDD_PROG= uuidd @UUIDD_CMT@UUIDD_MAN= uuidd.8 @@ -365,6 +366,10 @@ e2image.8: $(DEP_SUBSTITUTE) $(srcdir)/e2image.8.in $(E) " SUBST $@" $(Q) $(SUBSTITUTE_UPTIME) $(srcdir)/e2image.8.in e2image.8 +mksparse.8: $(DEP_SUBSTITUTE) $(srcdir)/mksparse.8.in + $(E) " SUBST $@" + $(Q) $(SUBSTITUTE_UPTIME) $(srcdir)/mksparse.8.in mksparse.8 + e4defrag.8: $(DEP_SUBSTITUTE) $(srcdir)/e4defrag.8.in $(E) " SUBST $@" $(Q) $(SUBSTITUTE_UPTIME) $(srcdir)/e4defrag.8.in e4defrag.8 diff --git a/misc/mksparse.8.in b/misc/mksparse.8.in new file mode 100644 index 0000000..8bc9955 --- /dev/null +++ b/misc/mksparse.8.in @@ -0,0 +1,86 @@ +.\" -*- nroff -*- +.\" Copyright 2011 by Taobao. All Rights Reserved. +.\" This file may be copied under the terms of the GNU Public License. +.\" +.TH MKSPARSE 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@" +.SH NAME +mksparse \- Make sparse file from an input file or the standard input +.SH SYNOPSIS +.B mksparse +[ +.B \-s +buffer-size +] +[ +.B \-i +input-file +] +.I sparse-file +.SH DESCRIPTION +The +.B mksparse +makes sparse file from an input file or the standard input. Currently popular +compressing tools like bzip2 or gunzip supports compressing a sparse file, +but in decompressing they fill zero bytes into output other than make a sparse +hole, which usually results a much larger file. If user downloads a +compressed raw file system image built by +.BR e2image (8) +on a very large file system, it is almost impossible to decompress it on a +desktop machine. +.PP +.B mksparse +can read the decompressed stream from standard input and make a sparse file +which takes less bytes on storage media. Here is the example, +.PP +.br +\ \fBe2image \-r /dev/hda1 \- | bzip2 > hda1.bz2\fR +.PP +\ \fBbunzip2 \-c hda1.bz2 | mksparse hda1_sparse.img\fR +.PP +.SH OPTIONS +.TP +.I "sparse-file" +The name specified to output file. +.TP +.BI \-i " input-file" +Other than from standard input, +.B mksparse +is also able to make a sparse file named by +.I sparse-file +from a regular file or device file which is specified by +.I input-file +.TP +.BI \-s " buffer-size" +By default +.B mksparse +reads 4KB bytes from input into its read buffer. If bytes in the buffer are +all zero, +.B mksparse +makes a sparse hole to +.I sparse-file +by seeking +.I buffer-size +bytes from current possion of +.I sparse-file +, otherwise it writes the buffer to +.I sparse-file +. After a hole is made or the buffer is written, +.B mksparse +continues to read next +.I buffer-size +bytes from input file into its read buffer until the end of input. A larger +.I buffer-size +means better I/O performance but less chance to make more sparse space in +.I sparse-file +. In most cases, the default 4KB +.I buffer-size +works quite well. +.SH AUTHOR +.B mksparse +is written by Robin Dong <sanbai@xxxxxxxxxx>. +.SH AVAILABILITY +.B mksparse +is part of the e2fsprogs package. +.SH SEE ALSO +.BR e2image (8) + -- 1.7.3.5 -- 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
