{"id":2208,"date":"2017-12-27T14:28:42","date_gmt":"2017-12-27T06:28:42","guid":{"rendered":"http:\/\/www.51cos.com\/?p=2208"},"modified":"2017-12-27T14:28:44","modified_gmt":"2017-12-27T06:28:44","slug":"%e5%9f%ba%e4%ba%8e-squashfs-%e6%9e%84%e5%bb%ba-linux-%e5%8f%af%e8%af%bb%e5%86%99%e6%96%87%e4%bb%b6%e7%b3%bb%e7%bb%9f","status":"publish","type":"post","link":"http:\/\/www.51cos.com\/?p=2208","title":{"rendered":"\u57fa\u4e8e SquashFS \u6784\u5efa Linux \u53ef\u8bfb\u5199\u6587\u4ef6\u7cfb\u7edf"},"content":{"rendered":"<p>\u672c\u6587\u6765\u6e90\uff1ahttps:\/\/www.ibm.com\/developerworks\/cn\/linux\/1306_qinzl_squashfs\/<\/p>\n<h2 id=\"major1\" class=\"ibm-h2\">\u5d4c\u5165\u5f0f Linux \u542f\u52a8\u8fc7\u7a0b<\/h2>\n<p>\u672c\u6587\u6240\u63cf\u8ff0\u7684\u7684 Linux Image \u7531 BootLoader\u3001kernel\u3001initrd\u3001rootfs \u7ec4\u6210\uff0c\u5b83\u4eec\u5171\u540c\u5b58\u5728\u4e8e\u4e00\u4e2a\u53ef\u4ee5\u542f\u52a8\u7684\u5b58\u50a8\u8bbe\u5907\u4e2d\uff08\u672c\u6587\u4ee5 USB \u4e3a\u4f8b\uff09\u3002\u7ec4\u6210\u67b6\u6784\u5982\u4e0b\uff1a<\/p>\n<h5 id=\"fig1\" class=\"ibm-h5\">\u56fe 1. \u53ef\u542f\u52a8 linux \u955c\u50cf\u6587\u4ef6\u7ed3\u6784<\/h5>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"ibm-downsize\" src=\"http:\/\/www.51cos.com\/wp-content\/uploads\/2017\/12\/680a66f4aacfac2817f1ca5018ffaed8.jpg\" alt=\"aaa\" width=\"349\" height=\"235\" \/><\/p>\n<p>\u5404\u4e2a\u6a21\u5757\u7684\u4f5c\u7528\u5982\u4e0b\uff1a<\/p>\n<ul class=\"ibm-bullet-list\">\n<li><strong>Boot Loader<\/strong>\uff1a\u7531 BIOS \u52a0\u8f7d\uff0c\u7528\u4e8e\u5c06\u540e\u7eed\u7684 Kernel \u548c initrd \u7684\u88c5\u8f7d\u5230\u5185\u5b58\u4e2d<\/li>\n<li><strong>kernel<\/strong>\uff1a\u4e3a initrd \u8fd0\u884c\u63d0\u4f9b\u57fa\u7840\u7684\u8fd0\u884c\u73af\u5883<\/li>\n<li><strong>initrd<\/strong>\uff1a\u68c0\u6d4b\u5e76\u52a0\u8f7d\u5404\u79cd\u9a71\u52a8\u7a0b\u5e8f<\/li>\n<li><strong>rootfs<\/strong>\uff1a\u6839\u6587\u4ef6\u7cfb\u7edf\uff0c\u7528\u6237\u7684\u5404\u79cd\u64cd\u4f5c\u90fd\u662f\u57fa\u4e8e\u8fd9\u4e2a\u88ab\u6700\u540e\u52a0\u8f7d\u7684\u6587\u4ef6\u7cfb\u7edf<\/li>\n<\/ul>\n<p>\u5176\u8c03\u7528\u987a\u5e8f\u662f Boot Loader-&gt;kernel-&gt;initrd-&gt;rootfs\u3002<\/p>\n<p>\u5f53\u673a\u5668\u4e0a\u7535\u65f6\u9996\u5148 BIOS \u4f1a\u542f\u52a8\uff0c\u7136\u540e\u88c5\u8f7d USB \u8bbe\u5907\u4e2d\u7684 Boot Loader\u3001kernel,\u3001initrd \u5230\u5185\u5b58\u4e2d\uff0c\u7531\u4e8e\u8fd9\u4e9b\u6587\u4ef6\u5927\u5c0f\u603b\u548c\u5c0f\u4e8e 10M\uff0c\u6240\u4ee5\u6211\u4eec\u76f4\u63a5\u62f7\u8d1d\u5230\u5185\u5b58\u4e2d\u518d\u6267\u884c\u4e0d\u4f1a\u6709\u95ee\u9898\u3002<\/p>\n<p>&nbsp;<\/p>\n<h2 id=\"major2\" class=\"ibm-h2\">\u53ea\u8bfb\u5f0f\u538b\u7f29\u6587\u4ef6\u7cfb\u7edf\u4ecb\u7ecd<\/h2>\n<p>\u5728\u5d4c\u5165\u5f0f\u7684\u73af\u5883\u4e4b\u4e0b\uff0c\u5185\u5b58\u548c\u5916\u5b58\u8d44\u6e90\u90fd\u9700\u8981\u8282\u7ea6\u4f7f\u7528\u3002\u5982\u679c\u4f7f\u7528 RAMDISK\uff08\u628a\u5185\u5b58\u5f53\u4f5c disk\uff09\u65b9\u5f0f\u6765\u4f7f\u7528\u6587\u4ef6\u7cfb\u7edf\uff0c\u90a3\u4e48\u5728\u7cfb\u7edf\u8fd0\u884c\u4e4b\u540e\uff0c\u9996\u5148\u8981\u628a\u5916\u5b58 (Flash) \u4e0a\u7684\u6620\u50cf\u6587\u4ef6\u89e3\u538b\u7f29\u5230\u5185\u5b58\u4e2d\uff0c\u6784\u9020\u8d77 RAMDISK \u73af\u5883\uff0c\u624d\u53ef\u4ee5\u5f00\u59cb\u8fd0\u884c\u7a0b\u5e8f\u3002\u4f46\u662f\u5b83\u4e5f\u6709\u5f88\u81f4\u547d\u7684\u5f31\u70b9\u3002\u5728\u6b63\u5e38\u60c5\u51b5\u4e0b\uff0c\u540c\u6837\u7684\u4ee3\u7801\u4e0d\u4ec5\u5728\u5916\u5b58\u4e2d\u5360\u636e\u4e86\u7a7a\u95f4 ( \u4ee5\u538b\u7f29\u540e\u7684\u5f62\u5f0f\u5b58\u5728 )\uff0c\u800c\u4e14\u8fd8\u5728\u5185\u5b58\u4e2d\u5360\u7528\u4e86\u66f4\u5927\u7684\u7a7a\u95f4 ( \u4ee5\u89e3\u538b\u7f29\u4e4b\u540e\u7684\u5f62\u5f0f\u5b58\u5728 )\uff0c\u8fd9\u8fdd\u80cc\u4e86\u5d4c\u5165\u5f0f\u73af\u5883\u4e0b\u5c3d\u91cf\u8282\u7701\u8d44\u6e90\u7684\u8981\u6c42\u3002\u4ee5\u4e0b\u4e24\u79cd\u65b9\u6848\u7684\u8bde\u751f\u5c31\u662f\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff1a<\/p>\n<p><strong>CramFS<\/strong><\/p>\n<p>CramFS \u6587\u4ef6\u7cfb\u7edf\u662f\u4e13\u95e8\u9488\u5bf9\u95ea\u5b58\u8bbe\u8ba1\u7684\u53ea\u8bfb\u538b\u7f29\u7684\u6587\u4ef6\u7cfb\u7edf\uff0c\u5b83\u5e76\u4e0d\u9700\u8981\u4e00\u6b21\u6027\u5730\u5c06\u6587\u4ef6\u7cfb\u7edf\u4e2d\u7684\u6240\u6709\u5185\u5bb9\u90fd\u89e3\u538b\u7f29\u5230\u5185\u5b58\u4e4b\u4e2d\uff0c\u800c\u53ea\u662f\u5728\u7cfb\u7edf\u9700\u8981\u8bbf\u95ee\u67d0\u4e2a\u4f4d\u7f6e\u7684\u6570\u636e\u7684\u65f6\u4faf\uff0c\u9a6c\u4e0a\u8ba1\u7b97\u51fa\u8be5\u6570\u636e\u5728 CramFS \u4e2d\u7684\u4f4d\u7f6e\uff0c\u5c06\u5176\u5b9e\u65f6\u5730\u89e3\u538b\u7f29\u5230\u5185\u5b58\u4e4b\u4e2d\uff0c\u7136\u540e\u901a\u8fc7\u5bf9\u5185\u5b58\u7684\u8bbf\u95ee\u6765\u83b7\u53d6\u6587\u4ef6\u7cfb\u7edf\u4e2d\u9700\u8981\u8bfb\u53d6\u7684\u6570\u636e\u3002CramFS \u4e2d\u7684\u89e3\u538b\u7f29\u4ee5\u53ca\u89e3\u538b\u7f29\u4e4b\u540e\u7684\u5185\u5b58\u4e2d\u6570\u636e\u5b58\u653e\u4f4d\u7f6e\u90fd\u662f\u7531 CramFS \u6587\u4ef6\u7cfb\u7edf\u672c\u8eab\u8fdb\u884c\u7ef4\u62a4\u7684\uff0c\u7528\u6237\u5e76\u4e0d\u9700\u8981\u4e86\u89e3\u5177\u4f53\u7684\u5b9e\u73b0\u8fc7\u7a0b\uff0c\u56e0\u6b64\u8fd9\u79cd\u65b9\u5f0f\u589e\u5f3a\u4e86\u900f\u660e\u5ea6\uff0c\u5bf9\u5f00\u53d1\u4eba\u5458\u6765\u8bf4\uff0c\u65e2\u65b9\u4fbf\uff0c\u53c8\u8282\u7701\u4e86\u5b58\u50a8\u7a7a\u95f4\u3002<\/p>\n<p><strong>SquashFS<\/strong><\/p>\n<p>SquashFS \u4e5f\u662f\u4e00\u4e2a\u53ea\u8bfb\u7684\u6587\u4ef6\u7cfb\u7edf\uff0c\u5b83\u53ef\u4ee5\u5c06\u6574\u4e2a\u6587\u4ef6\u7cfb\u7edf\u538b\u7f29\u5728\u4e00\u8d77\uff0c\u5b58\u653e\u5728\u67d0\u4e2a\u8bbe\u5907\uff0c\u67d0\u4e2a\u5206\u533a\u6216\u8005\u666e\u901a\u7684\u6587\u4ef6\u4e2d\u3002\u5982\u679c\u60a8\u5c06\u5176\u538b\u7f29\u5230\u4e00\u4e2a\u8bbe\u5907\u4e2d\uff0c\u90a3\u4e48\u60a8\u53ef\u4ee5\u5c06\u5176\u76f4\u63a5 mount \u8d77\u6765\u4f7f\u7528\uff0c\u800c\u5982\u679c\u5b83\u4ec5\u4ec5\u662f\u4e2a\u6587\u4ef6\u7684\u8bdd\uff0c\u60a8\u53ef\u4ee5\u5c06\u5176\u5f53\u4e3a\u4e00\u4e2a loopback \u8bbe\u5907\u4f7f\u7528\u3002<\/p>\n<p>\u66f4\u591a\u4fe1\u606f\u8bf7\u53c2\u8003\u201c<a href=\"http:\/\/en.wikipedia.org\/wiki\/SquashFS\">SquashFS<\/a>\u201d\u548c\u201c<a href=\"http:\/\/en.wikipedia.org\/wiki\/Cramfs\">CramFS<\/a>\u201d\u3002<\/p>\n<h2 id=\"major3\" class=\"ibm-h2\">Squash \u538b\u7f29\u6587\u4ef6\u7cfb\u7edf\u7684\u521b\u5efa<\/h2>\n<p>&#8220;<a href=\"http:\/\/pkgs.org\/archlinux\/archlinux-community-i686\/squashfs-tools-4.2-2-i686.pkg.tar.xz.html\">\u4e0b\u8f7d\u5e76\u5b89\u88c5 Squash \u5de5\u5177<\/a>&#8221;<\/p>\n<p>\u6b65\u9aa4 1\uff1a\u521b\u5efa\u7a7a\u7684\u6839\u6587\u4ef6\u7cfb\u7edf\uff0c\u6587\u4ef6\u7cfb\u7edf\u7684\u5927\u5c0f\u4e3a 65536 \u00d7 24000\/1024\/1024=1.5G\u3002\u63a5\u4e0b\u6765\u6211\u4eec\u4f1a\u5728\u8fd9\u4e2a\u7a7a\u7684\u6839\u6587\u4ef6\u7cfb\u7edf\u4e2d\u5b58\u653e\u6587\u4ef6\u3002<\/p>\n<div class=\"dw-article-sidebar ibm-background-cool-white-20\">\n<h5 id=\"sidebar1\">\u6ce8\u91ca\uff1a<\/h5>\n<p>dd: \u8bfb\u53d6\u6e90\u6587\u4ef6\u7684\u5185\u5bb9\u5e76\u521b\u5efa\u4e00\u4e2a\u65b0\u6587\u4ef6\uff0cif \u6307\u5b9a\u6e90\u6587\u4ef6\u5185\u5bb9\uff0cof \u6307\u5b9a\u65b0\u6587\u4ef6\u540d\u5b57\uff0cbs \u548c count \u6307\u5b9a\u65b0\u6587\u4ef6\u7684\u5927\u5c0f<br \/>\nmke2fs: \u5c06\u65b0\u521b\u5efa\u7684 rootfs \u683c\u5f0f\u5316\u4e3a Linux \u53ef\u8bc6\u522b\u7684\u6587\u4ef6\u7cfb\u7edf<\/p>\n<\/div>\n<h5 id=\"listing1\" class=\"ibm-h5\">\u6e05\u5355 1. \u521b\u5efa\u7a7a\u7684\u6839\u6587\u4ef6\u7cfb\u7edf<\/h5>\n<div class=\"ibm-syntax-container\">\n<div>\n<div id=\"highlighter_566729\" class=\"syntaxhighlighter  htmlscript\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"htmlscript plain\">dd if=\/dev\/zero of=rootfs bs=65536 count=24000 <\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"htmlscript plain\">mke2fs -F rootfs<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>\u6b65\u9aa4 2\uff1a\u6302\u8f7d\u7a7a\u7684\u6839\u6587\u4ef6\u7cfb\u7edf\uff0c\u5c06 1.5G \u7684\u6587\u4ef6\u7cfb\u7edf\u6302\u8f7d\u5728 mnt \u76ee\u5f55\u4e0b\uff0c\u7136\u540e\u901a\u8fc7 mnt \u76ee\u5f55\u5c06\u5185\u5bb9\u5199\u5165\u6839\u6587\u4ef6\u7cfb\u7edf\u3002<\/p>\n<h5 id=\"listing2\" class=\"ibm-h5\">\u6e05\u5355 2. \u6302\u8f7d\u7a7a\u7684\u6839\u6587\u4ef6\u7cfb\u7edf<\/h5>\n<div class=\"ibm-syntax-container\">\n<div>\n<div id=\"highlighter_686277\" class=\"syntaxhighlighter  htmlscript\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"htmlscript plain\">mkdir mnt <\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"htmlscript plain\">mount rootfs mnt -o loop<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>\u6b65\u9aa4 3\uff1a\u62f7\u8d1d\u6839\u6587\u4ef6\u76ee\u5f55\u7684\u5185\u5bb9\u5230\u6587\u4ef6\u7cfb\u7edf<\/p>\n<h5 id=\"listing3\" class=\"ibm-h5\">\u6e05\u5355 3. \u62f7\u8d1d\u6839\u6587\u4ef6\u76ee\u5f55\u7edf<\/h5>\n<div class=\"ibm-syntax-container\">\n<div>\n<div id=\"highlighter_978927\" class=\"syntaxhighlighter  htmlscript\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"htmlscript plain\">cp -rp yourRootDir mnt <\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"htmlscript plain\">umount mnt<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>\u62f7\u8d1d\u5b8c\u540e\u6839\u6587\u4ef6\u7cfb\u7edf\u7684\u5185\u5bb9\uff0c\u5982\u56fe 2 \u6240\u793a\uff1a<\/p>\n<h5 id=\"fig2\" class=\"ibm-h5\">\u56fe 2. \u6839\u6587\u4ef6\u7cfb\u7edf\u5185\u5bb9<\/h5>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"ibm-downsize\" src=\"http:\/\/www.51cos.com\/wp-content\/uploads\/2017\/12\/3e9c7989ec899ae2820d2b7d8ca063f0.jpg\" alt=\"aaa\" width=\"533\" height=\"30\" \/><\/p>\n<p>\u6b65\u9aa4 4\uff1a\u5b8c\u6210\u6839\u6587\u4ef6\u7cfb\u7edf\u7684\u521b\u5efa\uff0c\u8fd9\u65f6\u7684 rootfs \u6ca1\u6709\u88ab\u538b\u7f29\uff0c\u63a5\u4e0b\u6765\u6211\u4eec\u7528\u5de5\u5177\u5c06\u5176\u538b\u7f29\u6210 Squash \u683c\u5f0f\u7684\u6587\u4ef6\u7cfb\u7edf<\/p>\n<div class=\"dw-article-sidebar ibm-background-cool-white-20\">\n<h5 id=\"sidebar2\">\u6ce8\u91ca\uff1a<\/h5>\n<p>mksquashfs-4.1 \u662f\u5728\u5b89\u88c5 Squash \u5de5\u5177\u7684\u8fc7\u7a0b\u4e2d\u751f\u6210\u7684\u547d\u4ee4\uff0c\u7528\u4e8e\u5c06\u4e00\u4e2a\u6587\u4ef6\u5939\u4e0b\u7684\u5185\u5bb9\u6253\u5305\u5e76\u538b\u7f29\u6210\u4e00\u4e2a\u6587\u4ef6\u7cfb\u7edf\u3002\u5176\u540e\u7b2c\u4e00\u4e2a\u53c2\u6570\u4e3a\u6587\u4ef6\u5939\uff0c\u7b2c\u4e8c\u4e2a\u53c2\u6570\u4e3a\u751f\u6210\u7684\u6587\u4ef6\u7cfb\u7edf\u3002<\/p>\n<\/div>\n<h5 id=\"listing4\" class=\"ibm-h5\">\u6e05\u5355 4. \u521b\u5efa\u6839\u6587\u4ef6\u7cfb\u7edf<\/h5>\n<div class=\"ibm-syntax-container\">\n<div>\n<div id=\"highlighter_670988\" class=\"syntaxhighlighter  htmlscript\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<div class=\"line number3 index2 alt2\">3<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"htmlscript plain\">mkdir squashfs-dir <\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"htmlscript plain\">mv rootfs squshfs-dir <\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"htmlscript plain\">mksquashfs-4.1 squashfs-dir squashRootfs<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>\u5230\u8fd9\u91cc\u6211\u4eec\u5c31\u5b8c\u6210\u4e86 Squash \u538b\u7f29\u6587\u4ef6\u7cfb\u7edf\u7684\u521b\u5efa\u3002\u63a5\u4e0b\u6765\u6211\u4eec\u5c06\u8ba8\u8bba\u5982\u4f55\u5728 Linux \u542f\u52a8\u7684\u8fc7\u7a0b\u4e2d\u52a0\u8f7d\u8fd9\u4e2a\u538b\u7f29\u6587\u4ef6\u7cfb\u7edf\u3002<\/p>\n<h2 id=\"major4\" class=\"ibm-h2\">\u52a0\u8f7d\u538b\u7f29\u6587\u4ef6\u7cfb\u7edf\u6240\u4f7f\u7528\u7684\u5de5\u5177<\/h2>\n<p>\u5728\u52a0\u8f7d\u538b\u7f29\u6587\u4ef6\u7cfb\u7edf\u4e4b\u524d\uff0c\u6211\u4eec\u9700\u8981\u786e\u5b9a\u60a8\u7684 Linux \u5185\u6838\u652f\u6301\u8fd9\u79cd\u6587\u4ef6\u7cfb\u7edf\u3002 Device mapper \u662f Linux 2.6 \u5185\u6838\u4e2d\u63d0\u4f9b\u7684\u4e00\u79cd\u4ece\u903b\u8f91\u8bbe\u5907\u5230\u7269\u7406\u8bbe\u5907\u7684\u6620\u5c04\u6846\u67b6\u673a\u5236\uff0c\u5728\u8be5\u673a\u5236\u4e0b\uff0c\u7528\u6237\u53ef\u4ee5\u5f88\u65b9\u4fbf\u7684\u6839\u636e\u81ea\u5df1\u7684\u9700\u8981\u5236\u5b9a\u5b9e\u73b0\u5b58\u50a8\u8d44\u6e90\u7684\u7ba1\u7406\u7b56\u7565\u3002<\/p>\n<p>\u786e\u4fdd\u5728 initrd \u4e2d\u5df2\u7ecf\u96c6\u6210\u201c<a href=\"http:\/\/pkgs.org\/search\/?keyword=device-mapper\">device-mapper<\/a>\u201d<\/p>\n<h2 id=\"major5\" class=\"ibm-h2\">\u52a0\u8f7d Squash \u538b\u7f29\u6587\u4ef6\u7cfb\u7edf<\/h2>\n<p>\u53ef\u8bfb\u5199\u6587\u4ef6\u7cfb\u7edf\u539f\u7406\u5982\u56fe 3 \u6240\u793a\uff1a<\/p>\n<h5 id=\"fig3\" class=\"ibm-h5\">\u56fe 3. \u53ef\u8bfb\u5199\u6587\u4ef6\u7cfb\u7edf\u539f\u7406<\/h5>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"ibm-downsize\" src=\"http:\/\/www.51cos.com\/wp-content\/uploads\/2017\/12\/879f77a11b0649cb8af511fa5d6e4a7e.gif\" alt=\"aaa\" width=\"357\" height=\"201\" \/><\/p>\n<p>squashRootfs \u91cc\u9762\u5b58\u50a8\u4e86\u6211\u4eec\u539f\u59cb\u7684\u6839\u6587\u4ef6\u7cfb\u7edf\uff0c\u6211\u4eec\u5728\u6839\u6587\u4ef6\u7cfb\u7edf\u4e2d\u6240\u6709\u7684\u5199\u64cd\u4f5c\u4f1a\u76f4\u63a5\u5199\u5165 cowfile.out(cow:copy-on-write)\uff0c \u5f53\u6211\u4eec\u8bfb\u53d6\u6839\u6587\u4ef6\u7cfb\u7edf\u65f6\uff0c\u5982\u679c\u8bfb\u53d6\u7684\u5185\u5bb9\u6ca1\u6709\u53d8\u5316\uff0c\u5c06\u76f4\u63a5\u4ece squashRootfs \u4e2d\u8bfb\u53d6\uff0c\u5982\u679c\u8bfb\u53d6\u7684\u5185\u5bb9\u88ab\u66f4\u65b0\u8fc7\uff0c\u5c06\u4ece cowfile.out \u4e2d\u8bfb\u53d6\u3002cowfile.out \u6587\u4ef6\u7684\u5927\u5c0f\u4e00\u822c\u8981\u6bd4 squshRootfs \u5c0f\uff0c\u5982\u679c cowfile.out \u88ab\u5199\u6ee1\uff0c\u6839\u6587\u4ef6\u7cfb\u7edf\u7684\u8bfb\u5199\u64cd\u4f5c\u5c06\u4f1a\u51fa\u9519\uff0c\u56e0\u6b64\u6709\u5fc5\u8981\u7ed9 cowfile.out \u8bbe\u7f6e\u4e00\u4e2a\u5408\u7406\u7684\u5927\u5c0f\u4ee5\u9632\u6b62\u88ab\u5199\u6ee1\u3002<\/p>\n<p>\u7531\u4e8e rootfs \u662f\u88ab initrd \u52a0\u8f7d\u7684\uff0c\u56e0\u6b64\u6211\u4eec\u9700\u8981\u5728 initrd \u91cc\u9762\u52a0\u5165\u88c5\u8f7d rootfs \u7684\u4ee3\u7801\u3002initrd \u6574\u4e2a\u7684\u6267\u884c\u8fc7\u7a0b\u662f\u8c03\u7528 \/sbin\/init \u8fd9\u4e2a\u811a\u672c\u6587\u4ef6\uff0c\u56e0\u6b64\u6211\u4eec\u5728\u8fd9\u4e2a\u811a\u672c\u7684\u6700\u540e\u52a0\u5165\u4ee5\u4e0b\u4ee3\u7801\u903b\u8f91\u5373\u53ef\u3002<\/p>\n<div class=\"dw-article-sidebar ibm-background-cool-white-20\">\n<h5 id=\"sidebar3\">\u6ce8\u91ca\uff1a<\/h5>\n<p>1. dm-mirror \u4e3a device mapper \u5de5\u4f5c\u6240\u9700\u8981\u7684\u9a71\u52a8<\/p>\n<p>2. mknod: \u521b\u5efa\u4e00\u4e9b\u8bbe\u5907\u6587\u4ef6\uff0c\u53c2\u6570 1\uff1a\u8bbe\u5907\u6587\u4ef6\u540d \u53c2\u6570 2\uff1a\u8bbe\u5907\u7c7b\u578b \u53c2\u6570 3\uff1a\u4e3b\u8bbe\u5907\u53f7 \u53c2\u6570 4\uff1a\u6b21\u8bbe\u5907\u53f7<\/p>\n<p>3. \u5c06 squashRootfs \u901a\u8fc7 loop \u8bbe\u5907\u7684\u5f62\u5f0f\u6302\u8f7d\u5728\u76ee\u5f55 \/realroot\/mnt\/ \u4e0b<\/p>\n<p>4. \u5c06 \/realroot\/mnt\/rootfs \u8bbe\u7f6e\u4e3a loop \u8bbe\u5907\uff0c\u5e76\u548c \/dev\/loop1 \u7ed1\u5b9a<\/p>\n<p>5. &#8220;|&#8221;\u4e4b\u524d\u7684\u90e8\u5206\u662f\u6784\u5efa dmsetup \u7684\u53c2\u6570\uff0c\u5176\u4e2d $(blockdev &#8211;getsize \/dev\/loop1) \u8868\u793a\u521b\u5efa\u955c\u50cf\u6587\u4ef6\u7684\u5927\u5c0f\uff0c\/dev\/loop1 \/dev\/loop2 \u8868\u793a\u955c\u50cf\u6587\u4ef6\u662f\u4ee5 \/realroot\/mnt\/rootfs \u548c \/realroot\/mnt\/cowfile.out \u4e3a\u84dd\u672c\u8fdb\u884c\u521b\u5efa\u7684\uff08\u5728\u524d\u9762\u7684\u64cd\u4f5c\u4e2d loop1 \u548c loop2 \u5206\u522b\u8fdb\u884c\u4e86\u7ed1\u5b9a\u64cd\u4f5c\uff09<\/p>\n<\/div>\n<h5 id=\"listing5\" class=\"ibm-h5\">\u6e05\u5355 5. \u6784\u5efa\u53ef\u8bfb\u5199\u6587\u4ef6\u7cfb\u7edf\u811a\u672c<\/h5>\n<div class=\"ibm-syntax-container\">\n<div>\n<div id=\"highlighter_852935\" class=\"syntaxhighlighter  htmlscript\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<div class=\"line number3 index2 alt2\">3<\/div>\n<div class=\"line number4 index3 alt1\">4<\/div>\n<div class=\"line number5 index4 alt2\">5<\/div>\n<div class=\"line number6 index5 alt1\">6<\/div>\n<div class=\"line number7 index6 alt2\">7<\/div>\n<div class=\"line number8 index7 alt1\">8<\/div>\n<div class=\"line number9 index8 alt2\">9<\/div>\n<div class=\"line number10 index9 alt1\">10<\/div>\n<div class=\"line number11 index10 alt2\">11<\/div>\n<div class=\"line number12 index11 alt1\">12<\/div>\n<div class=\"line number13 index12 alt2\">13<\/div>\n<div class=\"line number14 index13 alt1\">14<\/div>\n<div class=\"line number15 index14 alt2\">15<\/div>\n<div class=\"line number16 index15 alt1\">16<\/div>\n<div class=\"line number17 index16 alt2\">17<\/div>\n<div class=\"line number18 index17 alt1\">18<\/div>\n<div class=\"line number19 index18 alt2\">19<\/div>\n<div class=\"line number20 index19 alt1\">20<\/div>\n<div class=\"line number21 index20 alt2\">21<\/div>\n<div class=\"line number22 index21 alt1\">22<\/div>\n<div class=\"line number23 index22 alt2\">23<\/div>\n<div class=\"line number24 index23 alt1\">24<\/div>\n<div class=\"line number25 index24 alt2\">25<\/div>\n<div class=\"line number26 index25 alt1\">26<\/div>\n<div class=\"line number27 index26 alt2\">27<\/div>\n<div class=\"line number28 index27 alt1\">28<\/div>\n<div class=\"line number29 index28 alt2\">29<\/div>\n<div class=\"line number30 index29 alt1\">30<\/div>\n<div class=\"line number31 index30 alt2\">31<\/div>\n<div class=\"line number32 index31 alt1\">32<\/div>\n<div class=\"line number33 index32 alt2\">33<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"htmlscript plain\"># \u52a0\u8f7d\u9a71\u52a8 ,\u53c2\u89c1\u6ce8\u91ca 1<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"htmlscript plain\">modprobe dm-mirror <\/code><\/div>\n<div class=\"line number3 index2 alt2\"><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"htmlscript plain\"># \u521b\u5efa\u8bbe\u5907 ,\u53c2\u89c1\u6ce8\u91ca 2<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"htmlscript plain\">mknod \/dev\/zero c 1 5 <\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"htmlscript plain\">mknod \/dev\/loop0 b 7 0 <\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"htmlscript plain\">mknod \/dev\/loop1 b 7 1 <\/code><\/div>\n<div class=\"line number8 index7 alt1\"><code class=\"htmlscript plain\">mknod \/dev\/loop2 b 7 2 <\/code><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"htmlscript plain\">mkdir \/dev\/cow <\/code><\/div>\n<div class=\"line number10 index9 alt1\"><code class=\"htmlscript plain\">mknod \/dev\/cow\/ctl b 241 255 <\/code><\/div>\n<div class=\"line number11 index10 alt2\"><code class=\"htmlscript plain\">mknod \/dev\/cow\/0 b 241 0 <\/code><\/div>\n<div class=\"line number12 index11 alt1\"><\/div>\n<div class=\"line number13 index12 alt2\"><code class=\"htmlscript plain\"># \u6302\u8f7d squash \u6839\u6587\u4ef6\u7cfb\u7edf\uff0c\u6302\u8f7d\u5b8c\u540e\u60a8\u53ef\u4ee5\u5728 \/realroot\/mnt\/ \u4e0b\u627e\u5230 rootfs \u6587\u4ef6 ,\u53c2\u89c1\u6ce8\u91ca 3<\/code><\/div>\n<div class=\"line number14 index13 alt1\"><code class=\"htmlscript plain\">mount \/realroot\/mnt\/squashRootfs \/realroot\/mnt\/ -o loop <\/code><\/div>\n<div class=\"line number15 index14 alt2\"><\/div>\n<div class=\"line number16 index15 alt1\"><code class=\"htmlscript plain\"># \u8bbe\u7f6e rootfs \u4e3a loop \u8bbe\u5907 ,\u53c2\u89c1\u6ce8\u91ca 4<\/code><\/div>\n<div class=\"line number17 index16 alt2\"><code class=\"htmlscript plain\">losetup \/dev\/loop1 \/realroot\/mnt\/rootfs <\/code><\/div>\n<div class=\"line number18 index17 alt1\"><\/div>\n<div class=\"line number19 index18 alt2\"><code class=\"htmlscript plain\"># \u521b\u5efa cowfile.out \u5e76\u6302\u8f7d\u4e3a loop \u8bbe\u5907\uff0c\u6211\u4eec\u5c06\u6765\u7684\u5199\u64cd\u4f5c\u90fd\u4f1a\u5199\u5165 cowfile.out <\/code><\/div>\n<div class=\"line number20 index19 alt1\"><code class=\"htmlscript plain\">dd if=\/dev\/zero of=\/realroot\/mnt\/cowfile.out bs=2K count=137500 <\/code><\/div>\n<div class=\"line number21 index20 alt2\"><code class=\"htmlscript plain\">losetup \/dev\/loop2 \/realroot\/mnt\/cowfile.out <\/code><\/div>\n<div class=\"line number22 index21 alt1\"><\/div>\n<div class=\"line number23 index22 alt2\"><code class=\"htmlscript plain\"># \u5c06 \/realroot\/mnt\/rootfs \u548c \/realroot\/mnt\/cowfile.out \u7ed3\u5408\u8d77\u6765\u521b\u5efa\u4e00\u4e2a\u903b\u8f91\u6839\u6587\u4ef6\u8bbe\u5907\uff0c<\/code><\/div>\n<div class=\"line number24 index23 alt1\"><code class=\"htmlscript plain\"># \u8bbe\u5907\u6587\u4ef6\u4e3a \/dev\/mapper\/root_fs\uff0c,\u53c2\u89c1\u6ce8\u91ca 5<\/code><\/div>\n<div class=\"line number25 index24 alt2\"><code class=\"htmlscript plain\">echo \"0 $(blockdev --getsize \/dev\/loop1) snapshot \/dev\/loop1 \/dev\/loop2 p 64\" | <\/code><\/div>\n<div class=\"line number26 index25 alt1\"><code class=\"htmlscript plain\">dmsetup create root_fs <\/code><\/div>\n<div class=\"line number27 index26 alt2\"><\/div>\n<div class=\"line number28 index27 alt1\"><code class=\"htmlscript plain\"># \u5c06\u4e0a\u9762\u521b\u5efa\u7684\u903b\u8f91\u6839\u6587\u4ef6\u8bbe\u5907 \/dev\/mapper\/root_fs \u6302\u8f7d\u5c31\u53ef\u4ee5\u770b\u5230\u4e00\u4e2a\u53ef\u8bfb\u5199\u7684\u6839\u6587\u4ef6\u7cfb\u7edf<\/code><\/div>\n<div class=\"line number29 index28 alt2\"><code class=\"htmlscript plain\">mount \/dev\/mapper\/root_fs \/realroot\/mnt\/Image <\/code><\/div>\n<div class=\"line number30 index29 alt1\"><\/div>\n<div class=\"line number31 index30 alt2\"><code class=\"htmlscript plain\"># \u5207\u6362\u5230\u6700\u7ec8\u53ef\u8bfb\u5199\u7684\u6839\u6587\u4ef6\u7cfb\u7edf<\/code><\/div>\n<div class=\"line number32 index31 alt1\"><code class=\"htmlscript plain\">cd \/realroot\/mnt\/Image <\/code><\/div>\n<div class=\"line number33 index32 alt2\"><code class=\"htmlscript plain\">chroot .\/sbin\/init -i<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>\u52a0\u4e0b\u6765\u60a8\u5c31\u53ef\u4ee5\u770b\u5230 rootfs \u7684\u6240\u6709\u5185\u5bb9\uff0c\u5982\u56fe 4 \u6240\u793a\uff1a<\/p>\n<h5 id=\"fig4\" class=\"ibm-h5\">\u56fe 4. \u88ab\u6302\u8f7d\u7684\u6839\u6587\u4ef6\u7cfb\u7edf\u5185\u5bb9<\/h5>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"ibm-downsize\" src=\"http:\/\/www.51cos.com\/wp-content\/uploads\/2017\/12\/6054a3f3ac960b575fd8879d0bcb8901.jpg\" alt=\"aaa\" width=\"476\" height=\"66\" \/><\/p>\n<p>\u8fd8\u53ef\u4ee5\u5728\u8fd9\u4e2a\u6587\u4ef6\u7cfb\u7edf\u4e2d\u8fdb\u884c\u5199\u64cd\u4f5c\uff0c\u5982\u56fe 5 \u6240\u793a\uff1a<\/p>\n<h5 id=\"fig5\" class=\"ibm-h5\">\u56fe 5. \u6839\u6587\u4ef6\u7cfb\u7edf\u7684\u5199\u64cd\u4f5c<\/h5>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"ibm-downsize\" src=\"http:\/\/www.51cos.com\/wp-content\/uploads\/2017\/12\/caaa2d12959ccf8e9e22f17ebfb0b6a8.jpg\" alt=\"aaa\" width=\"458\" height=\"68\" \/><\/p>\n<p>\u6700\u91cd\u8981\u7684\u662f rootfs \u6ca1\u6709\u88ab\u62f7\u8d1d\u5230\u5185\u5b58\u4e2d\u3002<\/p>\n<h2 id=\"major6\" class=\"ibm-h2\">\u7ed3\u675f\u8bed<\/h2>\n<p>\u7531\u4e8e\u7bc7\u5e45\u7684\u9650\u5236\uff0c\u672c\u6587\u53ea\u7ed9\u51fa\u4e86\u57fa\u672c\u7684\u63cf\u8ff0\u3002\u5e0c\u671b\u6709\u66f4\u4e00\u6b65\u4e86\u89e3\u7684\u8bfb\u8005\u53ef\u4ee5\u901a\u8fc7\u5bf9\u4ee5\u4e0b linux \u547d\u4ee4\u7684\u5b66\u4e60\u6765\u6df1\u5165\u4e86\u89e3\u3002<\/p>\n<p>\u6784\u5efa Squash \u538b\u7f29\u6587\u4ef6\u7cfb\u7edf\u6784\u6240\u4f7f\u7528\u7684\u4e3b\u8981\u547d\u4ee4\uff1a<\/p>\n<ul class=\"ibm-bullet-list\">\n<li><strong>mksquashfs:<\/strong>\u521b\u5efa Squash \u538b\u7f29\u6587\u4ef6\u7cfb\u7edf<\/li>\n<\/ul>\n<p>\u4f7f\u7528 Squash \u538b\u7f29\u6587\u4ef6\u7cfb\u7edf\u6784\u6240\u4f7f\u7528\u7684\u4e3b\u8981\u547d\u4ee4\uff1a<\/p>\n<ul class=\"ibm-bullet-list\">\n<li><strong>mknod:<\/strong>\u521b\u5efa Squash \u538b\u7f29\u6587\u4ef6\u7cfb\u7edf<\/li>\n<li><strong>losetup:<\/strong>\u8bbe\u7f6e\u5e76\u63a7\u5236 Loop \u8bbe\u5907<\/li>\n<li><strong>chroot:<\/strong>\u6539\u53d8\u6839\u76ee\u5f55<\/li>\n<li><strong>dmsetup:<\/strong>\u4f4e\u6c34\u5e73\u903b\u8f91\u5377\u7ba1\u7406<\/li>\n<\/ul>\n<div class=\"ibm-alternate-rule\"><\/div>\n<h4 id=\"artrelatedtopics\" class=\"ibm-h4\">\u76f8\u5173\u4e3b\u9898<\/h4>\n<ul>\n<li><a href=\"http:\/\/en.wikipedia.org\/wiki\/SquashFS\">SquashFS<\/a>\uff1a\u538b\u7f29\u7684\u53ea\u8bfb Linux \u6587\u4ef6\u7cfb\u7edf\u3002<\/li>\n<li><a href=\"http:\/\/en.wikipedia.org\/wiki\/Cramfs\">CramFS<\/a>\uff1a\u538b\u7f29\u7684 ROM \u6587\u4ef6\u7cfb\u7edf\u3002<\/li>\n<li><a href=\"http:\/\/linux.chinaunix.net\/docs\/2006-10-16\/2913.shtml\">Device Mapper<\/a>\uff1aLinux \u7cfb\u7edf\u5185\u6838\u4e2d\u7684 Device Mapper \u673a\u5236<\/li>\n<li>\u5728 <a href=\"http:\/\/www.ibm.com\/developerworks\/cn\/linux\/\">developerWorks Linux \u4e13\u533a<\/a>\u5bfb\u627e\u4e3a Linux \u5f00\u53d1\u4eba\u5458\uff08\u5305\u62ec <a href=\"http:\/\/www.ibm.com\/developerworks\/cn\/linux\/newto\/\">Linux \u65b0\u624b\u5165\u95e8<\/a>\uff09\u51c6\u5907\u7684\u66f4\u591a\u53c2\u8003\u8d44\u6599\u3002<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u672c\u6587\u6765\u6e90\uff1ahttps:\/\/www.ibm.com\/developerworks\/cn\/linux\/1306_q [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"class_list":["post-2208","post","type-post","status-publish","format-standard","hentry"],"_links":{"self":[{"href":"http:\/\/www.51cos.com\/index.php?rest_route=\/wp\/v2\/posts\/2208","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.51cos.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.51cos.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.51cos.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.51cos.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2208"}],"version-history":[{"count":1,"href":"http:\/\/www.51cos.com\/index.php?rest_route=\/wp\/v2\/posts\/2208\/revisions"}],"predecessor-version":[{"id":2214,"href":"http:\/\/www.51cos.com\/index.php?rest_route=\/wp\/v2\/posts\/2208\/revisions\/2214"}],"wp:attachment":[{"href":"http:\/\/www.51cos.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2208"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.51cos.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2208"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.51cos.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2208"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}