📄 buffer.c
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<!doctype html public "-//W3C//DTD HTML 3.2//EN"><html><head><title>Linux/fs/buffer.c</title><meta http-equiv=Content-Type content="text/html; charset=gb2312"><base href="http://oldlinux.org/lxr/http_cn/"></head><body bgcolor=white><div align=center> [<b><i>源代码浏览</i></b>] [<a href="diff/fs/buffer.c">区别标定</a>] [<a href="ident">标识符搜索</a>] [<a href="search">文本搜索</a>] [<a href="find">文件搜索</a>]</div><h1 align=center> <a href="http:/"> OldLinux</a> <a href="http:blurb.html"> 交叉引用</a><br> <a href="source/">Linux</a>/<a href="source/fs/">fs</a>/<a href="source/fs/buffer.c">buffer.c</a></h1><div align=center> <b>版本:</b> [<a href="source/fs/buffer.c?v=1.0">1.0</a>] [<a href="source/fs/buffer.c?v=0.99.11">0.99.11</a>] [<a href="source/fs/buffer.c?v=0.99">0.99</a>] [<a href="source/fs/buffer.c?v=0.98">0.98</a>] [<a href="source/fs/buffer.c?v=0.97">0.97</a>] [<a href="source/fs/buffer.c?v=0.96a">0.96a</a>] [<a href="source/fs/buffer.c?v=0.95">0.95</a>] [<a href="source/fs/buffer.c?v=0.12">0.12</a>] [<b><i>0.11</i></b>] [<a href="source/fs/buffer.c?v=0.01">0.01</a>] <br> <b>体系结构:</b> [<b><i>i386</i></b>] <br></div><hr><pre> <a name=L1 href="source/fs/buffer.c#L1">1</a> <b><i>/*</i></b> <a name=L2 href="source/fs/buffer.c#L2">2</a> <b><i> * linux/fs/buffer.c</i></b> <a name=L3 href="source/fs/buffer.c#L3">3</a> <b><i> *</i></b> <a name=L4 href="source/fs/buffer.c#L4">4</a> <b><i> * (C) 1991 Linus Torvalds</i></b> <a name=L5 href="source/fs/buffer.c#L5">5</a> <b><i> */</i></b> <a name=L6 href="source/fs/buffer.c#L6">6</a> <a name=L7 href="source/fs/buffer.c#L7">7</a> <b><i>/*</i></b> <a name=L8 href="source/fs/buffer.c#L8">8</a> <b><i> * 'buffer.c' implements the buffer-cache functions. Race-conditions have</i></b> <a name=L9 href="source/fs/buffer.c#L9">9</a> <b><i> * been avoided by NEVER letting a interrupt change a buffer (except for the</i></b> <a name=L10 href="source/fs/buffer.c#L10">10</a> <b><i> * data, of course), but instead letting the caller do it. NOTE! As interrupts</i></b> <a name=L11 href="source/fs/buffer.c#L11">11</a> <b><i> * can wake up a caller, some cli-sti sequences are needed to check for</i></b> <a name=L12 href="source/fs/buffer.c#L12">12</a> <b><i> * sleep-on-calls. These should be extremely quick, though (I hope).</i></b> <a name=L13 href="source/fs/buffer.c#L13">13</a> <b><i> */</i></b> <a name=L14 href="source/fs/buffer.c#L14">14</a> <a name=L15 href="source/fs/buffer.c#L15">15</a> <b><i>/*</i></b> <a name=L16 href="source/fs/buffer.c#L16">16</a> <b><i> * NOTE! There is one discordant note here: checking floppies for</i></b> <a name=L17 href="source/fs/buffer.c#L17">17</a> <b><i> * disk change. This is where it fits best, I think, as it should</i></b> <a name=L18 href="source/fs/buffer.c#L18">18</a> <b><i> * invalidate changed floppy-disk-caches.</i></b> <a name=L19 href="source/fs/buffer.c#L19">19</a> <b><i> */</i></b> <a name=L20 href="source/fs/buffer.c#L20">20</a> <a name=L21 href="source/fs/buffer.c#L21">21</a> #include <stdarg.h> <a name=L22 href="source/fs/buffer.c#L22">22</a> <a name=L23 href="source/fs/buffer.c#L23">23</a> #include <linux/config.h> <a name=L24 href="source/fs/buffer.c#L24">24</a> #include <linux/sched.h> <a name=L25 href="source/fs/buffer.c#L25">25</a> #include <linux/kernel.h> <a name=L26 href="source/fs/buffer.c#L26">26</a> #include <asm/system.h> <a name=L27 href="source/fs/buffer.c#L27">27</a> #include <asm/io.h> <a name=L28 href="source/fs/buffer.c#L28">28</a> <a name=L29 href="source/fs/buffer.c#L29">29</a> extern int <a href="ident?i=end">end</a>; <a name=L30 href="source/fs/buffer.c#L30">30</a> struct <a href="ident?i=buffer_head">buffer_head</a> * <a href="ident?i=start_buffer">start_buffer</a> = (struct <a href="ident?i=buffer_head">buffer_head</a> *) &<a href="ident?i=end">end</a>; <a name=L31 href="source/fs/buffer.c#L31">31</a> struct <a href="ident?i=buffer_head">buffer_head</a> * <a href="ident?i=hash_table">hash_table</a>[<a href="ident?i=NR_HASH">NR_HASH</a>]; <a name=L32 href="source/fs/buffer.c#L32">32</a> static struct <a href="ident?i=buffer_head">buffer_head</a> * <a href="ident?i=free_list">free_list</a>; <a name=L33 href="source/fs/buffer.c#L33">33</a> static struct <a href="ident?i=task_struct">task_struct</a> * <a href="ident?i=buffer_wait">buffer_wait</a> = <a href="ident?i=NULL">NULL</a>; <a name=L34 href="source/fs/buffer.c#L34">34</a> int <a href="ident?i=NR_BUFFERS">NR_BUFFERS</a> = 0; <a name=L35 href="source/fs/buffer.c#L35">35</a> <a name=L36 href="source/fs/buffer.c#L36">36</a> static inline void <a href="ident?i=wait_on_buffer">wait_on_buffer</a>(struct <a href="ident?i=buffer_head">buffer_head</a> * bh) <a name=L37 href="source/fs/buffer.c#L37">37</a> { <a name=L38 href="source/fs/buffer.c#L38">38</a> <a href="ident?i=cli">cli</a>(); <a name=L39 href="source/fs/buffer.c#L39">39</a> while (bh->b_lock) <a name=L40 href="source/fs/buffer.c#L40">40</a> <a href="ident?i=sleep_on">sleep_on</a>(&bh->b_wait); <a name=L41 href="source/fs/buffer.c#L41">41</a> <a href="ident?i=sti">sti</a>(); <a name=L42 href="source/fs/buffer.c#L42">42</a> } <a name=L43 href="source/fs/buffer.c#L43">43</a> <a name=L44 href="source/fs/buffer.c#L44">44</a> int <a href="ident?i=sys_sync">sys_sync</a>(void) <a name=L45 href="source/fs/buffer.c#L45">45</a> { <a name=L46 href="source/fs/buffer.c#L46">46</a> int i; <a name=L47 href="source/fs/buffer.c#L47">47</a> struct <a href="ident?i=buffer_head">buffer_head</a> * bh; <a name=L48 href="source/fs/buffer.c#L48">48</a> <a name=L49 href="source/fs/buffer.c#L49">49</a> <a href="ident?i=sync_inodes">sync_inodes</a>(); <b><i>/* write out inodes into buffers */</i></b> <a name=L50 href="source/fs/buffer.c#L50">50</a> bh = <a href="ident?i=start_buffer">start_buffer</a>; <a name=L51 href="source/fs/buffer.c#L51">51</a> for (i=0 ; i<<a href="ident?i=NR_BUFFERS">NR_BUFFERS</a> ; i++,bh++) { <a name=L52 href="source/fs/buffer.c#L52">52</a> <a href="ident?i=wait_on_buffer">wait_on_buffer</a>(bh); <a name=L53 href="source/fs/buffer.c#L53">53</a> if (bh->b_dirt) <a name=L54 href="source/fs/buffer.c#L54">54</a> <a href="ident?i=ll_rw_block">ll_rw_block</a>(<a href="ident?i=WRITE">WRITE</a>,bh); <a name=L55 href="source/fs/buffer.c#L55">55</a> } <a name=L56 href="source/fs/buffer.c#L56">56</a> return 0; <a name=L57 href="source/fs/buffer.c#L57">57</a> } <a name=L58 href="source/fs/buffer.c#L58">58</a> <a name=L59 href="source/fs/buffer.c#L59">59</a> int <a href="ident?i=sync_dev">sync_dev</a>(int dev) <a name=L60 href="source/fs/buffer.c#L60">60</a> { <a name=L61 href="source/fs/buffer.c#L61">61</a> int i; <a name=L62 href="source/fs/buffer.c#L62">62</a> struct <a href="ident?i=buffer_head">buffer_head</a> * bh; <a name=L63 href="source/fs/buffer.c#L63">63</a> <a name=L64 href="source/fs/buffer.c#L64">64</a> bh = <a href="ident?i=start_buffer">start_buffer</a>; <a name=L65 href="source/fs/buffer.c#L65">65</a> for (i=0 ; i<<a href="ident?i=NR_BUFFERS">NR_BUFFERS</a> ; i++,bh++) { <a name=L66 href="source/fs/buffer.c#L66">66</a> if (bh->b_dev != dev) <a name=L67 href="source/fs/buffer.c#L67">67</a> continue; <a name=L68 href="source/fs/buffer.c#L68">68</a> <a href="ident?i=wait_on_buffer">wait_on_buffer</a>(bh); <a name=L69 href="source/fs/buffer.c#L69">69</a> if (bh->b_dev == dev && bh->b_dirt) <a name=L70 href="source/fs/buffer.c#L70">70</a> <a href="ident?i=ll_rw_block">ll_rw_block</a>(<a href="ident?i=WRITE">WRITE</a>,bh); <a name=L71 href="source/fs/buffer.c#L71">71</a> } <a name=L72 href="source/fs/buffer.c#L72">72</a> <a href="ident?i=sync_inodes">sync_inodes</a>(); <a name=L73 href="source/fs/buffer.c#L73">73</a> bh = <a href="ident?i=start_buffer">start_buffer</a>; <a name=L74 href="source/fs/buffer.c#L74">74</a> for (i=0 ; i<<a href="ident?i=NR_BUFFERS">NR_BUFFERS</a> ; i++,bh++) { <a name=L75 href="source/fs/buffer.c#L75">75</a> if (bh->b_dev != dev) <a name=L76 href="source/fs/buffer.c#L76">76</a> continue; <a name=L77 href="source/fs/buffer.c#L77">77</a> <a href="ident?i=wait_on_buffer">wait_on_buffer</a>(bh); <a name=L78 href="source/fs/buffer.c#L78">78</a> if (bh->b_dev == dev && bh->b_dirt) <a name=L79 href="source/fs/buffer.c#L79">79</a> <a href="ident?i=ll_rw_block">ll_rw_block</a>(<a href="ident?i=WRITE">WRITE</a>,bh); <a name=L80 href="source/fs/buffer.c#L80">80</a> } <a name=L81 href="source/fs/buffer.c#L81">81</a> return 0; <a name=L82 href="source/fs/buffer.c#L82">82</a> } <a name=L83 href="source/fs/buffer.c#L83">83</a> <a name=L84 href="source/fs/buffer.c#L84">84</a> void inline <a href="ident?i=invalidate_buffers">invalidate_buffers</a>(int dev) <a name=L85 href="source/fs/buffer.c#L85">85</a> { <a name=L86 href="source/fs/buffer.c#L86">86</a> int i; <a name=L87 href="source/fs/buffer.c#L87">87</a> struct <a href="ident?i=buffer_head">buffer_head</a> * bh; <a name=L88 href="source/fs/buffer.c#L88">88</a> <a name=L89 href="source/fs/buffer.c#L89">89</a> bh = <a href="ident?i=start_buffer">start_buffer</a>; <a name=L90 href="source/fs/buffer.c#L90">90</a> for (i=0 ; i<<a href="ident?i=NR_BUFFERS">NR_BUFFERS</a> ; i++,bh++) { <a name=L91 href="source/fs/buffer.c#L91">91</a> if (bh->b_dev != dev) <a name=L92 href="source/fs/buffer.c#L92">92</a> continue; <a name=L93 href="source/fs/buffer.c#L93">93</a> <a href="ident?i=wait_on_buffer">wait_on_buffer</a>(bh); <a name=L94 href="source/fs/buffer.c#L94">94</a> if (bh->b_dev == dev) <a name=L95 href="source/fs/buffer.c#L95">95</a> bh->b_uptodate = bh->b_dirt = 0; <a name=L96 href="source/fs/buffer.c#L96">96</a> } <a name=L97 href="source/fs/buffer.c#L97">97</a> } <a name=L98 href="source/fs/buffer.c#L98">98</a> <a name=L99 href="source/fs/buffer.c#L99">99</a> <b><i>/*</i></b><a name=L100 href="source/fs/buffer.c#L100">100</a> <b><i> * This routine checks whether a floppy has been changed, and</i></b><a name=L101 href="source/fs/buffer.c#L101">101</a> <b><i> * invalidates all buffer-cache-entries in that case. This</i></b><a name=L102 href="source/fs/buffer.c#L102">102</a> <b><i> * is a relatively slow routine, so we have to try to minimize using</i></b><a name=L103 href="source/fs/buffer.c#L103">103</a> <b><i> * it. Thus it is called only upon a 'mount' or 'open'. This</i></b><a name=L104 href="source/fs/buffer.c#L104">104</a> <b><i> * is the best way of combining speed and utility, I think.</i></b><a name=L105 href="source/fs/buffer.c#L105">105</a> <b><i> * People changing diskettes in the middle of an operation deserve</i></b><a name=L106 href="source/fs/buffer.c#L106">106</a> <b><i> * to loose :-)</i></b><a name=L107 href="source/fs/buffer.c#L107">107</a> <b><i> *</i></b><a name=L108 href="source/fs/buffer.c#L108">108</a> <b><i> * NOTE! Although currently this is only for floppies, the idea is</i></b><a name=L109 href="source/fs/buffer.c#L109">109</a> <b><i> * that any additional removable block-device will use this routine,</i></b><a name=L110 href="source/fs/buffer.c#L110">110</a> <b><i> * and that mount/open needn't know that floppies/whatever are</i></b>⌨️ 快捷键说明
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