1 | /* |
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2 | * mapper.h - Kernel cache for VFS files/directories definition. |
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3 | * |
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4 | * Authors Mohamed Lamine Karaoui (2015) |
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5 | * Alain Greiner (2016,2017,2018,2019) |
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6 | * |
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7 | * Copyright (c) UPMC Sorbonne Universites |
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8 | * |
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9 | * This file is part of ALMOS-MKH. |
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10 | * |
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11 | * ALMOS-MKH is free software; you can redistribute it and/or modify it |
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12 | * under the terms of the GNU General Public License as published by |
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13 | * the Free Software Foundation; version 2.0 of the License. |
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14 | * |
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15 | * ALMOS-MKH is distributed in the hope that it will be useful, but |
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16 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
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17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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18 | * General Public License for more details. |
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19 | * |
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20 | * You should have received a copy of the GNU General Public License |
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21 | * along with ALMOS-MKH; if not, write to the Free Software Foundation, |
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22 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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23 | */ |
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24 | |
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25 | #ifndef _MAPPER_H_ |
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26 | #define _MAPPER_H_ |
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27 | |
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28 | #include <hal_kernel_types.h> |
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29 | #include <hal_atomic.h> |
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30 | #include <xlist.h> |
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31 | #include <grdxt.h> |
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32 | #include <rwlock.h> |
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33 | |
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34 | /**** Forward declarations ****/ |
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35 | |
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36 | struct page_s; |
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37 | struct vfs_inode_s; |
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38 | |
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39 | /******************************************************************************************* |
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40 | * This mapper_t object implements the kernel cache for a given VFS file or directory. |
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41 | * There is one mapper per file/dir. |
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42 | * - It is implemented as a three levels radix tree, entirely stored in the same cluster |
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43 | * as the inode representing the file/directory. |
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44 | * - The fast retrieval key is the page index in the file. |
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45 | * The ix1_width, ix2_width, ix3_width sub-indexes are configuration parameters. |
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46 | * - The leaves are pointers on physical page descriptors, dynamically allocated |
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47 | * in the same cluster as the radix tree. |
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48 | * - The mapper is protected by a "remote_rwlock", to support several simultaneous |
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49 | * "readers", and only one "writer". |
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50 | * - A "reader" thread, calling the mapper_remote_get_page() function to get a page |
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51 | * descriptor pointer from the page index in file, can be running in any cluster. |
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52 | * - A "writer" thread, calling the mapper_handle_miss() function to handle a page miss |
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53 | * must be local (running in the mapper cluster). |
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54 | * - The vfs_fs_move_page() function access the file system to handle a mapper miss, |
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55 | * or update a dirty page on device. |
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56 | * - The vfs_mapper_load_all() functions is used to load all pages of a directory |
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57 | * into the mapper (prefetch). |
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58 | * - the mapper_move_user() function is used to move data to or from an user buffer. |
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59 | * This user space buffer can be physically distributed in several clusters. |
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60 | * - the mapper_move_kernel() function is used to move data to or from a remote kernel |
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61 | * buffer, that can be physically located in any cluster. |
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62 | * - In the present implementation the cache size for a given file increases on demand, |
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63 | * and the allocated memory is only released when the inode is destroyed. |
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64 | * |
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65 | * WARNING : This mapper implementation makes the assumption that the PPM page size |
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66 | * is 4 Kbytes. This code should be modified to support a generic page size, |
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67 | * defined by the CONFIG_PPM_PAGE_SIZE parameter. |
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68 | ******************************************************************************************/ |
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69 | |
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70 | |
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71 | /******************************************************************************************* |
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72 | * This structure defines the mapper descriptor. |
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73 | ******************************************************************************************/ |
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74 | |
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75 | typedef struct mapper_s |
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76 | { |
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77 | struct vfs_inode_s * inode; /*! owner inode */ |
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78 | uint32_t fs_type; /*! file system type */ |
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79 | grdxt_t rt; /*! embedded pages cache descriptor (radix tree) */ |
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80 | remote_rwlock_t lock; /*! several readers / only one writer */ |
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81 | uint32_t refcount; /*! several vsegs can refer the same file */ |
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82 | xlist_entry_t vsegs_root; /*! root of list of vsegs refering this mapper */ |
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83 | xlist_entry_t wait_root; /*! root of list of threads waiting on mapper */ |
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84 | list_entry_t dirty_root; /*! root of list of dirty pages */ |
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85 | } |
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86 | mapper_t; |
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87 | |
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88 | /******************************************************************************************* |
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89 | * This function allocates physical memory for a mapper descriptor, in cluster |
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90 | * identified by the <cxy> argument. It initializes it (refcount <= 0) / inode <= NULL). |
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91 | * It can be executed by any thread running in any cluster. |
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92 | ******************************************************************************************* |
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93 | * @ cxy : target cluster identifier. |
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94 | * @ type : FS type. |
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95 | * @ return an extended pointer on created mapper if success / return NULL if no memory |
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96 | ******************************************************************************************/ |
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97 | xptr_t mapper_create( cxy_t cxy, |
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98 | uint32_t type ); |
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99 | |
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100 | /******************************************************************************************* |
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101 | * This function releases all physical memory allocated for a mapper, identified |
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102 | * by the <mapper_xp> argument. Both the mapper descriptor and the radix tree are released. |
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103 | * It does NOT synchronize dirty pages. Use the vfs_sync_inode() function if required. |
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104 | * It can be executed by any thread running in any cluster. |
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105 | ******************************************************************************************* |
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106 | * @ mapper_xp : extended pointer on target mapper. |
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107 | ******************************************************************************************/ |
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108 | void mapper_destroy( xptr_t mapper_xp ); |
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109 | |
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110 | /******************************************************************************************* |
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111 | * This function load from the IOC device a missing page identified by the <page_id> |
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112 | * argument into a - possibly remote - mapper identified by the <mapper_xp> argument. |
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113 | * It can be executed by a thread running in any cluster. |
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114 | * It allocates a physical page from the remote cluster PPM, initialises it by accessing |
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115 | * the IOC device, and registers the page in the remote mapper radix tree. |
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116 | * WARNING : the calling function mapper_remote_get_page() is supposed to take and release |
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117 | * the lock protecting the mapper in WRITE_MODE. |
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118 | ******************************************************************************************* |
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119 | * @ mapper_xp : [in] extended pointer on remote mapper. |
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120 | * @ page_id : [in] missing page index in file. |
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121 | * @ page_xp : [out] buffer for extended pointer on missing page descriptor. |
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122 | * @ return 0 if success / return -1 if IOC cannot be accessed. |
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123 | ******************************************************************************************/ |
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124 | error_t mapper_handle_miss( xptr_t mapper_xp, |
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125 | uint32_t page_id, |
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126 | xptr_t * page_xp ); |
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127 | |
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128 | /******************************************************************************************* |
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129 | * This function removes a physical page from a - possibly remote - mapper, |
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130 | * and releases the page to the remote PPM. |
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131 | * It can be executed by any thread running in any cluster. |
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132 | * It takes the mapper lock in WRITE_MODE to update the mapper. |
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133 | ******************************************************************************************* |
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134 | * @ mapper : extended pointer on the remote mapper. |
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135 | * @ page : local pointer on the page in remote mapper. |
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136 | ******************************************************************************************/ |
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137 | void mapper_remote_release_page( xptr_t mapper_xp, |
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138 | struct page_s * page ); |
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139 | |
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140 | /******************************************************************************************* |
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141 | * This function move data between a remote mapper, identified by the <mapper_xp> argument, |
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142 | * and a distributed user buffer. It can be called by a thread running in any cluster. |
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143 | * It is called by the vfs_user_move() to implement sys_read() and sys_write() syscalls. |
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144 | * If required, the data transfer is split in "fragments", where one fragment contains |
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145 | * contiguous bytes in the same mapper page. |
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146 | * It uses "hal_uspace" accesses to move a fragment to/from the user buffer. |
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147 | * In case of write, the dirty bit is set for all pages written in the mapper. |
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148 | * The mapper being an extendable cache, it is automatically extended when required. |
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149 | * The "offset" field in the file descriptor, and the "size" field in inode descriptor |
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150 | * are not modified by this function. |
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151 | ******************************************************************************************* |
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152 | * @ mapper_xp : extended pointer on mapper. |
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153 | * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false. |
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154 | * @ file_offset : first byte to move in file. |
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155 | * @ u_buf : user space pointer on user buffer. |
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156 | * @ size : number of bytes to move. |
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157 | * returns O if success / returns -1 if error. |
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158 | ******************************************************************************************/ |
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159 | error_t mapper_move_user( xptr_t mapper_xp, |
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160 | bool_t to_buffer, |
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161 | uint32_t file_offset, |
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162 | void * u_buf, |
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163 | uint32_t size ); |
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164 | |
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165 | /******************************************************************************************** |
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166 | * This function move <size> bytes from/to a remote mapper, identified by the <mapper_xp> |
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167 | * argument, to/from a remote kernel buffer, identified by the <buffer_xp> argument. |
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168 | * It can be called by a thread running in any cluster. |
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169 | * If required, the data transfer is split in "fragments", where one fragment contains |
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170 | * contiguous bytes in the same mapper page. Each fragment uses a "remote_memcpy". |
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171 | * In case of write to mapper, the dirty bit is set for all pages written in the mapper. |
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172 | ******************************************************************************************* |
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173 | * @ mapper_xp : extended pointer on mapper. |
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174 | * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false. |
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175 | * @ file_offset : first byte to move in file. |
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176 | * @ buffer_xp : extended pointer on kernel buffer. |
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177 | * @ size : number of bytes to move. |
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178 | * returns O if success / returns -1 if error. |
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179 | ******************************************************************************************/ |
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180 | error_t mapper_move_kernel( xptr_t mapper_xp, |
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181 | bool_t to_buffer, |
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182 | uint32_t file_offset, |
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183 | xptr_t buffer_xp, |
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184 | uint32_t size ); |
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185 | |
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186 | /******************************************************************************************* |
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187 | * This function returns an extended pointer on a page descriptor for a regular mapper |
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188 | * (i.e. this mapper is NOT the FAT mapper), identified by the <mapper_xp> argument. |
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189 | * The page is identified by <page_id> argument (page index in the file). |
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190 | * It can be executed by a thread running in any cluster, as it uses remote |
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191 | * access primitives to scan the mapper. |
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192 | * In case of miss, this function takes the mapper lock in WRITE_MODE, and call the |
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193 | * mapper_handle_miss() to load the missing page from device to mapper, using an RPC |
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194 | * when the mapper is remote. |
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195 | ******************************************************************************************* |
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196 | * @ mapper_xp : extended pointer on the mapper. |
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197 | * @ page_id : page index in file |
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198 | * @ returns extended pointer on page descriptor if success / return XPTR_NULL if error. |
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199 | ******************************************************************************************/ |
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200 | xptr_t mapper_get_page( xptr_t mapper_xp, |
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201 | uint32_t page_id ); |
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202 | |
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203 | /******************************************************************************************* |
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204 | * This function returns an extended pointer on a page descriptor for the FAT mapper. |
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205 | * The page is identified by <page_id> argument (page index in the FAT mapper). |
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206 | * It can be executed by a thread running in any cluster, as it uses remote |
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207 | * access primitives to scan the mapper. |
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208 | * In case of miss, this function takes the mapper lock in WRITE_MODE, and call the |
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209 | * mapper_handle_miss() to load the missing page from device to mapper, using an RPC |
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210 | * when the mapper is remote. |
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211 | ******************************************************************************************* |
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212 | * @ mapper_xp : extended pointer on the mapper. |
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213 | * @ page_id : page index in file |
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214 | * @ returns extended pointer on page descriptor if success / return XPTR_NULL if error. |
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215 | ******************************************************************************************/ |
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216 | xptr_t mapper_get_fat_page( xptr_t mapper_xp, |
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217 | uint32_t page_id ); |
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218 | |
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219 | /******************************************************************************************* |
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220 | * This function allows to read a single word in a mapper seen as and array of uint32_t. |
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221 | * It has bee designed to support remote access to the FAT mapper of the FATFS. |
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222 | * It can be called by any thread running in any cluster. |
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223 | * In case of miss, it takes the mapper lock in WRITE_MODE, load the missing |
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224 | * page from device to mapper, and release the mapper lock. |
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225 | ******************************************************************************************* |
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226 | * @ mapper_xp : [in] extended pointer on the mapper. |
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227 | * @ page_id : [in] page index in mapper. |
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228 | * @ word_id : [in] 32 bits word index in page. |
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229 | * @ value : [out] local pointer on destination buffer. |
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230 | * @ returns 0 if success / return -1 if error. |
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231 | ******************************************************************************************/ |
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232 | error_t mapper_remote_get_32( xptr_t mapper_xp, |
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233 | uint32_t page_id, |
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234 | uint32_t word_id, |
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235 | uint32_t * value ); |
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236 | |
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237 | /******************************************************************************************* |
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238 | * This function allows to write a single word to a mapper seen as and array of uint32_t. |
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239 | * It has been designed to support remote access to the FAT mapper of the FATFS. |
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240 | * It can be called by any thread running in any cluster. |
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241 | * In case of miss, it takes the mapper lock in WRITE_MODE, load the missing |
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242 | * page from device to mapper, and release the mapper lock. |
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243 | * It does not update the FAT on IOC device. |
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244 | ******************************************************************************************* |
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245 | * @ mapper_xp : [in] extended pointer on the mapper. |
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246 | * @ page_id : [in] page index in mapper. |
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247 | * @ word_id : [in] 32 bits word index in page. |
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248 | * @ value : [in] value to be written. |
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249 | * @ returns 0 if success / return -1 if error. |
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250 | ******************************************************************************************/ |
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251 | error_t mapper_remote_set_32( xptr_t mapper_xp, |
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252 | uint32_t page_id, |
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253 | uint32_t word_id, |
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254 | uint32_t value ); |
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255 | |
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256 | /******************************************************************************************* |
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257 | * This function scan all pages present in the mapper identified by the <mapper_xp> |
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258 | * argument, and synchronize all pages marked as "dirty" on disk. |
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259 | * These pages are unmarked and removed from the local PPM dirty_list. |
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260 | * It can be called by any thread running in any cluster. |
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261 | ******************************************************************************************* |
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262 | * @ mapper_xp : [in] extended pointer on local mapper. |
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263 | * @ returns 0 if success / return -1 if error. |
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264 | ******************************************************************************************/ |
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265 | error_t mapper_sync( xptr_t mapper_xp ); |
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266 | |
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267 | /******************************************************************************************* |
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268 | * This debug function displays the content of a given page of a given mapper, identified |
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269 | * by the <mapper_xp> and <page_id> arguments. |
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270 | * The number of bytes to display in page is defined by the <nbytes> argument. |
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271 | * The format is eigth (32 bits) words per line in hexadecimal. |
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272 | * It can be called by any thread running in any cluster. |
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273 | ******************************************************************************************* |
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274 | * @ mapper_xp : [in] extended pointer on the mapper. |
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275 | * @ page_id : [in] page_index in mapper. |
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276 | * @ nbytes : [in] number of bytes in page. |
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277 | * @ returns 0 if success / return -1 if error. |
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278 | ******************************************************************************************/ |
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279 | void mapper_display_page( xptr_t mapper_xp, |
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280 | uint32_t page_id, |
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281 | uint32_t nbytes ); |
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282 | |
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283 | |
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284 | #endif /* _MAPPER_H_ */ |
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