source: trunk/kernel/mm/mapper.h @ 656

Last change on this file since 656 was 656, checked in by alain, 4 years ago

Fix several bugs in the FATFS and in the VFS,
related to the creation of big files requiring
more than 4 Kbytes (one cluster) on device.
File size: 15.1 KB
Line 
1/*
2 * mapper.h - Kernel cache for VFS files/directories definition.
3 *
4 * Authors   Mohamed Lamine Karaoui (2015)
5 *           Alain Greiner (2016,2017,2018,2019)
6 *
7 * Copyright (c)  UPMC Sorbonne Universites
8 *
9 * This file is part of ALMOS-MKH.
10 *
11 * ALMOS-MKH is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; version 2.0 of the License.
14 *
15 * ALMOS-MKH is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
22 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25#ifndef _MAPPER_H_
26#define _MAPPER_H_
27
28#include <hal_kernel_types.h>
29#include <hal_atomic.h>
30#include <xlist.h>
31#include <grdxt.h>
32#include <rwlock.h>
33
34/****  Forward declarations ****/
35
36struct page_s;
37struct vfs_inode_s;
38
39/*******************************************************************************************
40 * This mapper_t object implements the kernel cache for a given VFS file or directory.
41 * There is one mapper per file/dir. It is implemented as a three levels radix tree,
42 * entirely stored in the same cluster as the inode representing the file/dir.
43 * - The fast retrieval key is the page index in the file.
44 *   The ix1_width, ix2_width, ix3_width sub-indexes are configuration parameters.
45 * - The leaves are pointers on physical page descriptors, dynamically allocated
46 *   in the local cluster.
47 * - The mapper is protected by a "remote_rwlock", to support several simultaneous
48 *   "readers", and only one "writer".
49 * - A "reader" thread, calling the mapper_remote_get_page() function to get a page
50 *   descriptor pointer from the page index in file, can be running in any cluster.
51 * - A "writer" thread, calling the mapper_handle_miss() function to handle a page miss
52 *   must be local (running in the mapper cluster).
53 * - The vfs_fs_move_page() function access the file system to handle a mapper miss,
54 *   or update a dirty page on device.
55 * - The vfs_mapper_load_all() functions is used to load all pages of a directory
56 *   into the mapper (prefetch).
57 * - the mapper_move_user() function is used to move data to or from an user buffer.
58 *   This user space buffer can be physically distributed in several clusters.
59 * - the mapper_move_kernel() function is used to move data to or from a remote kernel
60 *   buffer, that can be physically located in any cluster.
61 * - In the present implementation the cache size for a given file increases on demand,
62 *   and the  allocated memory is only released when the mapper/inode is destroyed.
63 *
64 * TODO the "type" field in mapper descriptor is redundant and probably unused.
65 ******************************************************************************************/
66
67
68/*******************************************************************************************
69 * This structure defines the mapper descriptor.
70 ******************************************************************************************/
71
72typedef struct mapper_s
73{
74        struct vfs_inode_s * inode;           /*! owner inode                                     */
75    uint32_t             type;        /*! file system type                                */
76        grdxt_t              rt;              /*! embedded pages cache descriptor (radix tree)    */
77        remote_rwlock_t      lock;        /*! several readers / only one writer               */
78        uint32_t                 refcount;    /*! several vsegs can refer the same file           */
79        xlist_entry_t        vsegs_root;  /*! root of list of vsegs refering this mapper      */
80        xlist_entry_t        wait_root;   /*! root of list of threads waiting on mapper       */
81    list_entry_t         dirty_root;  /*! root of list of dirty pages                     */
82}
83mapper_t;
84
85/*******************************************************************************************
86 * This function allocates physical memory for a mapper descriptor, and initializes it
87 * (refcount <= 0) / inode <= NULL).
88 * It must be executed by a thread running in the cluster containing the mapper.
89 *******************************************************************************************
90 * @ type   : type of the mapper to create.
91 * @ return : pointer on created mapper if success / return NULL if no memory
92 ******************************************************************************************/
93mapper_t * mapper_create( vfs_fs_type_t type );
94
95/*******************************************************************************************
96 * This function releases all physical memory allocated for a mapper.
97 * Both the mapper descriptor and the radix tree are released.
98 * It does NOT synchronize dirty pages. Use the vfs_sync_inode() function if required.
99 * It must be executed by a thread running in the cluster containing the mapper.
100 *******************************************************************************************
101 * @ mapper      : target mapper.
102 ******************************************************************************************/
103void mapper_destroy( mapper_t * mapper );
104
105/*******************************************************************************************
106 * This function load from the IOC device a missing page identified by the <page_id>
107 * argument into a - possibly remote - mapper identified by the <mapper_xp> argument.
108 * It can be executed by a thread running in any cluster.
109 * It allocates a physical page from the remote cluster PPM, initialises it by accessing
110 * the IOC device, and registers the page in the remote mapper radix tree.
111 * WARNING : the calling function mapper_remote_get_page() is supposed to take and release
112 * the lock protecting the mapper in WRITE_MODE.
113 *******************************************************************************************
114 * @ mapper_xp   : [in]  extended pointer on remote mapper.
115 * @ page_id     : [in]  missing page index in file.
116 * @ page_xp     : [out] buffer for extended pointer on missing page descriptor.
117 * @ return 0 if success / return -1 if IOC cannot be accessed.
118 ******************************************************************************************/
119error_t mapper_remote_handle_miss( xptr_t     mapper_xp,
120                                   uint32_t   page_id,
121                                   xptr_t   * page_xp );
122
123/*******************************************************************************************
124 * This function removes a physical page from a - possibly remote - mapper,
125 * and releases the page to the remote PPM.
126 * It can be executed by any thread running in any cluster.
127 * It takes the mapper lock in WRITE_MODE to update the mapper.
128 *******************************************************************************************
129 * @ mapper     : extended pointer on the remote mapper.
130 * @ page       : local pointer on the page in remote mapper.
131 ******************************************************************************************/
132void mapper_remote_release_page( xptr_t          mapper_xp,
133                                 struct page_s * page );
134
135/*******************************************************************************************
136 * This function move data between a remote mapper, identified by the <mapper_xp> argument,
137 * and a distributed user buffer. It can be called by a thread running in any cluster.
138 * It is called by the vfs_user_move() to implement sys_read() and sys_write() syscalls.
139 * If required, the data transfer is split in "fragments", where one fragment contains
140 * contiguous bytes in the same mapper page.
141 * It uses "hal_uspace" accesses to move a fragment to/from the user buffer.
142 * In case of write, the dirty bit is set for all pages written in the mapper.
143 * The mapper being an extendable cache, it is automatically extended when required.
144 * The "offset" field in the file descriptor, and the "size" field in inode descriptor
145 * are not modified by this function.
146 *******************************************************************************************
147 * @ mapper_xp    : extended pointer on mapper.
148 * @ to_buffer    : mapper -> buffer if true / buffer -> mapper if false.
149 * @ file_offset  : first byte to move in file.
150 * @ u_buf        : user space pointer on user buffer.
151 * @ size         : number of bytes to move.
152 * returns O if success / returns -1 if error.
153 ******************************************************************************************/
154error_t mapper_move_user( xptr_t     mapper_xp,
155                          bool_t     to_buffer,
156                          uint32_t   file_offset,
157                          void     * u_buf,
158                          uint32_t   size );
159
160/********************************************************************************************
161 * This function move <size> bytes from/to a remote mapper, identified by the <mapper_xp>
162 * argument, to/from a remote kernel buffer, identified by the <buffer_xp> argument.
163 * It can be called by a thread running in any cluster.
164 * If required, the data transfer is split in "fragments", where one fragment contains
165 * contiguous bytes in the same mapper page. Each fragment uses a "remote_memcpy".
166 * In case of write to mapper, the dirty bit is set for all pages written in the mapper.
167 *******************************************************************************************
168 * @ mapper_xp    : extended pointer on mapper.
169 * @ to_buffer    : mapper -> buffer if true / buffer -> mapper if false.
170 * @ file_offset  : first byte to move in file.
171 * @ buffer_xp    : extended pointer on kernel buffer.
172 * @ size         : number of bytes to move.
173 * returns O if success / returns -1 if error.
174 ******************************************************************************************/
175error_t mapper_move_kernel( xptr_t     mapper_xp,
176                            bool_t     to_buffer,
177                            uint32_t   file_offset,
178                            xptr_t     buffer_xp,
179                            uint32_t   size );
180
181/*******************************************************************************************
182 * This function returns an extended pointer on a page descriptor.
183 * The - possibly remote - mapper is identified by the <mapper_xp> argument.
184 * The page is identified by <page_id> argument (page index in the file).
185 * It can be executed by a thread running in any cluster, as it uses remote
186 * access primitives to scan the mapper.
187 * In case of miss, this function takes the mapper lock in WRITE_MODE, and call the
188 * mapper_handle_miss() to load the missing page from device to mapper, using an RPC
189 * when the mapper is remote.
190 *******************************************************************************************
191 * @ mapper_xp  : extended pointer on the mapper.
192 * @ page_id    : page index in file
193 * @ returns extended pointer on page descriptor if success / return XPTR_NULL if error.
194 ******************************************************************************************/
195xptr_t mapper_remote_get_page( xptr_t    mapper_xp,
196                               uint32_t  page_id );
197
198/*******************************************************************************************
199 * This function allows to read a single word in a mapper seen as and array of uint32_t.
200 * It has bee designed to support remote access to the FAT mapper of the FATFS.
201 * It can be called by any thread running in any cluster.
202 * In case of miss, it takes the mapper lock in WRITE_MODE, load the missing
203 * page from device to mapper, and release the mapper lock.
204 *******************************************************************************************
205 * @ mapper_xp  : [in]  extended pointer on the mapper.
206 * @ page_id    : [in]  page index in mapper.
207 * @ word_id    : [in]  32 bits word index in page.
208 * @ value      : [out] local pointer on destination buffer.
209 * @ returns 0 if success / return -1 if error.
210 ******************************************************************************************/
211error_t mapper_remote_get_32( xptr_t     mapper_xp,
212                              uint32_t   page_id,
213                              uint32_t   word_id,
214                              uint32_t * value );
215
216/*******************************************************************************************
217 * This function allows to write a single word to a mapper seen as and array of uint32_t.
218 * It has been designed to support remote access to the FAT mapper of the FATFS.
219 * It can be called by any thread running in any cluster.
220 * In case of miss, it takes the mapper lock in WRITE_MODE, load the missing
221 * page from device to mapper, and release the mapper lock.
222 * It does not update the FAT on IOC device.
223 *******************************************************************************************
224 * @ mapper_xp  : [in]  extended pointer on the mapper.
225 * @ page_id    : [in]  page index in mapper.
226 * @ word_id    : [in]  32 bits word index in page.
227 * @ value      : [in]  value to be written.
228 * @ returns 0 if success / return -1 if error.
229 ******************************************************************************************/
230error_t mapper_remote_set_32( xptr_t     mapper_xp,
231                              uint32_t   page_id,
232                              uint32_t   word_id,
233                              uint32_t   value );
234
235/*******************************************************************************************
236 * This function scan all pages present in the mapper identified by the <mapper> argument,
237 * and synchronize all pages marked as "dirty" on disk.
238 * These pages are unmarked and removed from the local PPM dirty_list.
239 * This function must be called by a local thread running in same cluster as the mapper.
240 * A remote thread must call the RPC_MAPPER_SYNC function.
241 *******************************************************************************************
242 * @ mapper     : [in]  local pointer on local mapper.
243 * @ returns 0 if success / return -1 if error.
244 ******************************************************************************************/
245error_t mapper_sync( mapper_t *  mapper );
246
247/*******************************************************************************************
248 * This debug function displays the content of a given page of a given mapper, identified
249 * by the <mapper_xp> and <page_xp> arguments.
250 * The number of bytes to display in page is defined by the <nbytes> argument.
251 * The format is eigth (32 bits) words per line in hexadecimal.
252 * It can be called by any thread running in any cluster.
253 *******************************************************************************************
254 * @ mapper_xp  : [in]  extended pointer on the mapper.
255 * @ page_xp    : [in]  extended pointer on page descriptor.
256 * @ nbytes     : [in]  number of bytes in page.
257 * @ returns 0 if success / return -1 if error.
258 ******************************************************************************************/
259void mapper_display_page( xptr_t     mapper_xp,
260                          xptr_t     page_xp,
261                          uint32_t   nbytes );
262
263
264#endif /* _MAPPER_H_ */
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