source: trunk/kernel/fs/fatfs.h @ 653

Last change on this file since 653 was 638, checked in by alain, 5 years ago

Fix a bug in the FFT work function (wrong upriv buffer allocation).

File size: 29.8 KB
Line 
1/*
2 * fatfs.h - FATFS file system API definition.
3 *
4 * Author    Mohamed Lamine Karaoui (2014,2015)
5 *           Alain Greiner (2016,2017,2018)
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 _FATFS_H_
26#define _FATFS_H_
27
28#include <hal_kernel_types.h>
29#include <remote_queuelock.h>
30#include <vfs.h>
31#include <dev_ioc.h>
32
33
34/**************************************************************************************
35 * The FATFS File System implements a FAT32 read/write file system.
36 *
37 * The FATFS specific extensions to the generic VFS are the following:
38 * 1) The vfs_ctx_t "extend" field is a void* pointing on the fatfs_ctx_t structure.
39 *    This structure contains various general informations such as the total
40 *    number of sectors in FAT region, the number of bytes per sector, the number
41 *    of sectors per cluster, the lba of FAT region, the lba of data region, or the
42 *    cluster index for the root directory. It contains also an extended pointer
43 *    on the FAT mapper.
44 * 2) The vfs_inode_t "extend" contains, for each inode,
45 *    the first FAT cluster index (after cast to intptr).
46 * 3) The vfs_dentry_t "extend" field contains, for each dentry, the entry index
47 *    in the FATFS directory (32 bytes per FATFS entry).
48 *************************************************************************************/
49 
50///////////////////////////////////////////////////////////////////////////////////////////
51
52/*************** Partition Boot Sector Format **********************************/
53//                                     offset |  length
54#define BS_JMPBOOT                          0 ,  3
55#define BS_OEMNAME                          3 ,  8
56#define BPB_BYTSPERSEC                     11 ,  2
57#define BPB_SECPERCLUS                     13 ,  1
58#define BPB_RSVDSECCNT                     14 ,  2
59#define BPB_NUMFATS                        16 ,  1
60#define BPB_ROOTENTCNT                     17 ,  2
61#define BPB_TOTSEC16                       19 ,  2
62#define BPB_MEDIA                          21 ,  1
63#define BPB_FATSZ16                        22 ,  2
64#define BPB_SECPERTRK                      24 ,  2
65#define BPB_NUMHEADS                       26 ,  2
66#define BPB_HIDDSEC                        28 ,  4
67#define BPB_TOTSEC32                       32 ,  4
68#define BPB_PARTITION_TABLE               446 , 64
69
70// FAT 32
71#define BPB_FAT32_FATSZ32                  36 ,  4
72#define BPB_FAT32_EXTFLAGS                 40 ,  2
73#define BPB_FAT32_FSVER                    42 ,  2
74#define BPB_FAT32_ROOTCLUS                 44 ,  4
75#define BPB_FAT32_FSINFO                   48 ,  2
76#define BPB_FAT32_BKBOOTSEC                50 ,  2
77#define BS_FAT32_DRVNUM                    64 ,  1
78#define BS_FAT32_BOOTSIG                   66 ,  1
79#define BS_FAT32_VOLID                     67 ,  4
80#define BS_FAT32_VOLLAB                    71 , 11
81#define BS_FAT32_FILSYSTYPE                82 ,  8
82
83// Partitions
84#define FIRST_PARTITION_ACTIVE            446 ,  8
85#define FIRST_PARTITION_BEGIN_LBA         454 ,  4
86#define FIRST_PARTITION_SIZE              458 ,  4
87#define SECOND_PARTITION_ACTIVE           462 ,  8
88#define SECOND_PARTITION_BEGIN_LBA        470 ,  4
89#define SECOND_PARTITION_SIZE             474 ,  4
90#define THIRD_PARTITION_ACTIVE            478 ,  8
91#define THIRD_PARTITION_BEGIN_LBA         486 ,  4
92#define THIRD_PARTITION_SIZE              490 ,  4
93#define FOURTH_PARTITION_ACTIVE           494 ,  8
94#define FOURTH_PARTITION_BEGIN_LBA        502 ,  4
95#define FOURTH_PARTITION_SIZE             506 ,  4   
96/*******************************************************************************/
97
98#define MBR_SIGNATURE_POSITION            510 , 2
99#define MBR_SIGNATURE_VALUE               0xAA55 
100
101/************** FAT_FS_INFO SECTOR  ********************************************/
102#define FS_SIGNATURE_VALUE_1              0x52526141
103#define FS_SIGNATURE_VALUE_2              0x72724161
104#define FS_SIGNATURE_VALUE_3              0x000055AA 
105#define FS_SIGNATURE_POSITION_1           0   , 4 
106#define FS_SIGNATURE_POSITION_2           484 , 4
107#define FS_SIGNATURE_POSITION_3           508 , 4 
108#define FS_FREE_CLUSTERS                  488 , 4
109#define FS_FREE_CLUSTER_HINT              492 , 4
110/*******************************************************************************/
111
112#define DIR_ENTRY_SIZE          32
113                   
114#define NAME_MAX_SIZE           31
115
116/******* SFN Directory Entry Structure (32 bytes) ******************************/
117//                            offset | length
118#define DIR_NAME                   0 , 11   // dir_entry name
119#define DIR_ATTR                  11 ,  1   // attributes
120#define DIR_NTRES                 12 ,  1   // reserved for the OS       
121#define DIR_CRT_TIMES_TENTH       13 ,  1
122#define DIR_FST_CLUS_HI           20 ,  2   // cluster index 16 MSB bits
123#define DIR_WRT_TIME              22 ,  2   // time of last write
124#define DIR_WRT_DATE              24 ,  2   // date of last write
125#define DIR_FST_CLUS_LO           26 ,  2   // cluster index 16 LSB bit
126#define DIR_FILE_SIZE             28 ,  4   // dir_entry size (up to 4 Gbytes)
127/*******************************************************************************/
128
129/******* LFN Directory Entry Structure  (32 bytes) *****************************/
130//                            offset | length
131#define LDIR_ORD                   0 ,  1   // Sequence number (from 0x01 to 0x0f)   
132#define LDIR_NAME_1                1 , 10   // name broken into 3 parts
133#define LDIR_ATTR                 11 ,  1   // attributes (must be 0x0F)
134#define LDIR_TYPE                 12 ,  1   // directory type (must be 0x00)
135#define LDIR_CHKSUM               13 ,  1   // checksum of name in short dir 
136#define LDIR_NAME_2               14 , 12
137#define LDIR_RSVD                 26 ,  2   // artifact of previous fat (must be 0)
138#define LDIR_NAME_3               28 ,  4   
139/*******************************************************************************/
140
141/***********************  DIR_ATTR values  (attributes) ************************/
142#define ATTR_READ_ONLY            0x01
143#define ATTR_HIDDEN               0x02
144#define ATTR_SYSTEM               0x04
145#define ATTR_VOLUME_ID            0x08
146#define ATTR_DIRECTORY            0x10
147#define ATTR_ARCHIVE              0x20
148#define ATTR_LONG_NAME_MASK       0x0f      // READ_ONLY|HIDDEN|SYSTEM|VOLUME_ID
149/*******************************************************************************/
150
151/********************* DIR_ORD special values **********************************/
152#define FREE_ENTRY                0xE5     // this entry is free in the directory
153#define NO_MORE_ENTRY             0x00     // no more entry in the directory
154/*******************************************************************************/
155
156/******************** CLuster Index Special Values *****************************/
157#define FREE_CLUSTER              0x00000000
158#define RESERVED_CLUSTER          0x00000001
159#define BAD_CLUSTER               0x0FFFFFF7
160#define END_OF_CHAIN_CLUSTER_MIN  0x0ffffff8
161#define END_OF_CHAIN_CLUSTER_MAX  0x0fffffff
162/*******************************************************************************/
163
164/****  Forward declarations  ****/
165
166struct mapper_s;
167struct page_s;
168struct vfs_ctx_s;
169struct vfs_inode_s;
170struct vfs_dentry_s;
171
172/*****************************************************************************************
173 * This structure defines a FATFS specific context extension to the VFS context.
174 * This fatfs context is replicated in all clusters.
175 *
176 * WARNING 1 : All access to the FAT are protected by a remote_rwlock.
177 * - it is taken in READ mode by the fatfs_get_cluster() function to scan the
178 *   linked list associated to a given inode.
179 * - it is taken in WRITE mode by the fatfs_cluster_alloc() and fatfs_release_inode()
180 *   functions to modify the FAT in both the FAT mapper and on IOC device.
181 *
182 * WARNING 2 : Most fields are constant values, but the <free_cluster_hint>,
183 * <free_clusters>, <lock>, and the <fs_info_buffer> are shared variables,
184 * that can be modified by any thread running in any cluster. The <fs_info_buffer>
185 * contains a copy of the FS_INFO sector, and is only allocated in the FAT cluster
186 * (cluster 0). It is used to synchronously update the free clusters info on IOC device.
187 *  => For all these variables, only the values stored in the FAT cluster must be used.
188 ****************************************************************************************/
189
190typedef struct fatfs_ctx_s
191{
192    /* read-only constants replicated in all clusters                                   */
193    uint32_t            fat_sectors_count;     /*! number of sectors in FAT region      */
194    uint32_t            bytes_per_sector;      /*! number of bytes per sector           */
195    uint32_t            sectors_per_cluster;   /*! number of sectors per cluster        */
196    uint32_t            fat_begin_lba;         /*! lba of FAT region                    */
197    uint32_t            cluster_begin_lba;     /*! lba of data region                   */
198    uint32_t            fs_info_lba;           /*! lba of FS_INFO sector                */
199    uint32_t            root_dir_cluster;      /*! cluster index for  root directory    */
200    xptr_t              fat_mapper_xp;         /*! extended pointer on FAT mapper       */
201
202    /* shared variables (only the copy in FAT cluster must be used)                     */
203    uint32_t            free_cluster_hint;     /*! cluster[hint+1] is the first free    */
204    uint32_t            free_clusters;         /*! free clusters number                 */
205    remote_rwlock_t     lock;                  /*! exclusive access to FAT              */
206    uint8_t           * fs_info_buffer;        /*! local pointer on FS_INFO buffer      */
207}
208fatfs_ctx_t;
209
210//////////////////////////////////////////////////////////////////////////////////////////
211//              FATFS specific extern functions 
212//////////////////////////////////////////////////////////////////////////////////////////
213
214/*****************************************************************************************
215 * This function access the FAT (File Allocation Table), stored in the FAT mapper, and
216 * returns in <searched_cluster> the FATFS cluster index for a given page of a given
217 * inode identified by the <first_cluster> and <page_id> arguments.
218 * It can be called by a thread running in any cluster, as it uses remote access
219 * primitives when the FAT mapper is remote.
220 * The FAT is actually an array of uint32_t slots. Each slot in this array contains the
221 * index of another slot in this array, to form one linked list for each file stored on
222 * device in the FATFS file system. This index in the FAT array is also the index of the
223 * FATFS cluster on the device. One FATFS cluster is supposed to contain one PPM page.
224 * For a given file, the entry point in the FAT is simply the index of the FATFS cluster
225 * containing the first page of the file. The FAT mapper being a cache, this function
226 * updates the FAT mapper from informations stored on IOC device in case of miss.
227 *****************************************************************************************
228 * @ first_cluster       : [in]  index of first FATFS cluster allocated to the file.
229 * @ page_id             : [in]  index of searched page in file.
230 * @ searched_cluster    : [out] found FATFS cluster index.
231 * @ return 0 if success / return -1 if a FAT mapper miss cannot be solved.
232 ****************************************************************************************/
233error_t fatfs_get_cluster( uint32_t   first_cluster,
234                           uint32_t   page_id,
235                           uint32_t * searched_cluster );
236
237/*****************************************************************************************
238 * This function display the content of the FATFS context copy in cluster identified
239 * by the <cxy> argument.
240 * This function can be called by a thread running in any cluster.
241 *****************************************************************************************
242 * @ cxy       :  target cluster identifier.
243 ****************************************************************************************/
244void fatfs_display_ctx( cxy_t cxy );
245
246/*****************************************************************************************
247 * This function access the FAT mapper to display one page of the File Allocation Table.
248 * It loads the requested page fom IOC device to FAT mapper if required.
249 * This function can be called by a thread running in any cluster.
250 *****************************************************************************************
251 * @ page_id     : page index in FAT mapper (one page is 4 Kbytes).
252 * @ nb_entries  : number of entries (one entry is 4 bytes).
253 ****************************************************************************************/
254void fatfs_display_fat( uint32_t  page_id,
255                        uint32_t  nb_entries );
256
257
258//////////////////////////////////////////////////////////////////////////////////////////
259// Generic API: These functions are called by the kernel VFS,
260//              and must be implemented by all File Systems.
261//////////////////////////////////////////////////////////////////////////////////////////
262
263/*****************************************************************************************
264 * This fuction allocates memory from local cluster for a FATFS context descriptor.
265 *****************************************************************************************
266 * @ return a pointer on the created context / return NULL if failure.
267 ****************************************************************************************/
268fatfs_ctx_t * fatfs_ctx_alloc( void );
269
270/*****************************************************************************************
271 * This function access the boot device, and initialises the local FATFS context,
272 * from informations contained in the boot record. This initialisation includes the
273 * creation of the FAT mapper in cluster 0.
274 *****************************************************************************************
275 * @ vfs_ctx   : local pointer on VFS context for FATFS.
276 ****************************************************************************************/
277void fatfs_ctx_init( fatfs_ctx_t * fatfs_ctx );
278
279/*****************************************************************************************
280 * This function releases memory dynamically allocated for the FATFS context extension.
281 *****************************************************************************************
282 * @ vfs_ctx   : local pointer on VFS context.
283 ****************************************************************************************/
284void fatfs_ctx_destroy( fatfs_ctx_t * fatfs_ctx );
285
286/*****************************************************************************************
287 * This function implements the generic vfs_fs_add_dentry() function for the FATFS.
288 *****************************************************************************************
289 * This function updates a directory mapper identified by the <inode> argument
290 * to add a new directory entry identified by the <dentry> argument.
291 * All modified pages in the directory mapper are synchronously updated on IOC device.
292 * It must be called by a thread running in the cluster containing the directory inode.
293 *
294 * Implementation note : this function works in two steps:
295 * - It scan the set of 32 bytes FATFS directry entries, using two embedded loops 
296 *   to find the end of directory (NO_MORE_ENTRY marker).
297 * - Then it writes 3, 4, or 5 directory entries (depending on the name length), using
298 *   a 5 steps FSM (one state per entry to be written), updates on IOC device the
299 *   modified pages, and updates the dentry extension field, that must contain
300 *   the dentry index in FATFS directory.
301 *****************************************************************************************
302 * @ inode    : local pointer on directory inode.
303 * @ dentry   : local pointer on dentry.
304 * @ return 0 if success / return ENOENT if not found, or EIO if no access to IOC device.
305 ****************************************************************************************/
306error_t fatfs_add_dentry( struct vfs_inode_s  * inode,
307                          struct vfs_dentry_s * dentry );
308
309/*****************************************************************************************
310 * This function implements the generic vfs_fs_remove_dentry() function for the FATFS.
311 *****************************************************************************************
312 * This function updates a directory identified by the <inode> argument
313 * to remove a directory entry identified by the <dentry> argument.
314 * All modified pages in directory mapper are synchronously updated on IOC device.
315 * It must be called by a thread running in the cluster containing the inode.
316 *
317 * Implementation note: this function uses the dentry extension to directly access
318 * the NORMAL directory entry and invalidate all involved LFN entries. Then it
319 * updates the modified pages on IOC device.
320 *****************************************************************************************
321 * @ inode    : local pointer on directory inode.
322 * @ dentry   : local pointer on dentry.
323 * @ return 0 if success / return ENOENT if not found, or EIO if no access to IOC device.
324 ****************************************************************************************/
325error_t fatfs_remove_dentry( struct vfs_inode_s  * inode,
326                             struct vfs_dentry_s * dentry );
327
328/*****************************************************************************************
329 * This function implements the generic vfs_fs_new_dentry() function for the FATFS.
330 *****************************************************************************************
331 * It scan a parent directory mapper, identified by the <parent_inode> argument to find
332 * a directory entry identified by the <name> argument.  In case of success, it
333 * initializes the inode/dentry couple, identified by the  <child_inode_xp> argument
334 * in the Inode Tree. The child inode descriptor, and the associated dentry descriptor
335 * must have been previously allocated by the caller.
336 * - It set the "type", "size", and "extend" fields in the child inode descriptor.
337 * - It set the " extend" field in the dentry descriptor.
338 * It must be called by a thread running in the cluster containing the parent inode.
339 *****************************************************************************************
340 * @ parent_inode    : local pointer on parent inode (directory).
341 * @ name            : child name.
342 * @ child_inode_xp  : extended pointer on remote child inode (file or directory).
343 * @ return 0 if success / return -1 if child not found.
344 ****************************************************************************************/
345error_t fatfs_new_dentry( struct vfs_inode_s * parent_inode,
346                          char               * name,
347                          xptr_t               child_inode_xp );
348
349/*****************************************************************************************
350 * This function implements the generic vfs_fs_update_dentry() function for the FATFS.
351 *****************************************************************************************
352 * It update the size of a directory entry identified by the <dentry> argument in
353 * the mapper of a directory identified by the <inode> argument, as defined by the
354 * <size> argument.
355 * It scan the mapper to find the entry identified by the dentry "name" field.
356 * It set the "size" field in the in the directory mapper AND marks the page as DIRTY.
357 * It must be called by a thread running in the cluster containing the directory inode.
358 *****************************************************************************************
359 * @ inode        : local pointer on inode (directory).
360 * @ dentry       : local pointer on dentry (for name).
361 * @ size         : new size value.
362 * @ return 0 if success / return ENOENT if child not found.
363 ****************************************************************************************/
364error_t fatfs_update_dentry( struct vfs_inode_s  * inode,
365                             struct vfs_dentry_s * dentry,
366                             uint32_t              size );
367
368/*****************************************************************************************
369 * This function implements the generic vfs_fs_get_user_dir() function for the FATFS.
370 *****************************************************************************************
371 * It is called by the remote_dir_create() function to scan the mapper of a directory
372 * identified by the <inode> argument, and copy up to <max_dirent> valid dentries to a
373 * local dirent array, defined by the <array> argument. The <min_dentry> argument defines
374 * the index of the first dentry to be copied to the target dirent array.
375 * This function returns in the <entries> buffer the number of dentries actually written,
376 * and signals in the <done> buffer when the last valid entry has been found.
377 * If the <detailed> argument is true, a dentry/inode couple that does not exist in
378 * the Inode Tree is dynamically created, and all dirent fields are documented in the
379 * dirent array. Otherwise, only the dentry name is documented.
380 * It must be called by a thread running in the cluster containing the directory inode.
381 *****************************************************************************************
382 * @ inode      : [in]  local pointer on directory inode.
383 * @ array      : [in]  local pointer on array of dirents.
384 * @ max_dirent : [in]  max number of slots in dirent array.
385 * @ min_dentry : [in]  index of first dentry to be copied into array.
386 * @ detailed   : [in]  dynamic inode creation if true.
387 * @ entries    : [out] number of dentries actually copied into array.
388 * @ done       : [out] Boolean true when last entry found.
389 * @ return 0 if success / return -1 if failure.
390 ****************************************************************************************/
391error_t fatfs_get_user_dir( struct vfs_inode_s * inode,
392                            struct dirent      * array, 
393                            uint32_t             max_dirent,
394                            uint32_t             min_dentry,
395                            bool_t               detailed,
396                            uint32_t           * entries,
397                            bool_t             * done );
398
399/*****************************************************************************************
400 * This function implements the generic vfs_fs_sync_inode() function for the FATFS.
401 *****************************************************************************************
402 * It updates the FATFS on the IOC device for a given inode identified by
403 * the <inode> argument. It scan all pages registered in the associated mapper,
404 * and copies from mapper to device each page marked as dirty.
405 * WARNING : The target <inode> cannot be a directory, because all modifications in a
406 * directory are synchronously done on the IOC device by the two fatfs_add_dentry()
407 * and fatfs_remove_dentry() functions.
408 *****************************************************************************************
409 * @ inode   : local pointer on inode.
410 * @ return 0 if success / return -1 if failure during IOC device access.
411 ****************************************************************************************/
412error_t fatfs_sync_inode( struct vfs_inode_s * inode );
413
414/*****************************************************************************************
415 * This function implements the generic vfs_fs_sync_fat() function for the FATFS.
416 *****************************************************************************************
417 * It updates the FAT on the IOC device for the FAT itself.
418 * It scan all clusters registered in the FAT mapper, and copies from mapper to device
419 * each page marked as dirty.
420 *
421 * TODO : the current implementation check ALL pages in the FAT region, even if most
422 * pages are empty, and not copied in mapper. It is sub-optimal.
423 * - A first solution is to maintain in the FAT context two "dirty_min" and "dirty_max"
424 *  variables defining the smallest/largest dirty page index in FAT mapper...
425 *****************************************************************************************
426 * @ return 0 if success / return -1 if failure during IOC device access.
427 ****************************************************************************************/
428error_t fatfs_sync_fat( void );
429
430/*****************************************************************************************
431 * This function implements the generic vfs_fs_sync_fsinfo() function for the FATFS.
432 *****************************************************************************************
433 * It checks the current values of the "free_clusters" and "free_cluster_hint" variables
434 * in the FS_INFO sector on IOC, versus the values stored in the fatfs context.
435 * As these values are synchronously updated on IOC device at each modification,
436 * it does nothing if the values are equal. It updates the FS_INFO sector on IOC device,
437 * and displays a warning message on TXT0 if they are not equal.
438 * This function can be called by any thread running in any cluster.
439 *****************************************************************************************
440 * @ return 0 if success / return -1 if failure during IOC device access.
441 ****************************************************************************************/
442error_t fatfs_sync_free_info( void );
443
444/*****************************************************************************************
445 * This function implements the generic vfs_fs_cluster_alloc() function for the FATFS.
446 *****************************************************************************************
447 * It access the FAT (File allocation table), stored in the FAT mapper, and returns
448 * in <searched_cluster> the FATFS cluster index of a free cluster.
449 * It can be called by a thread running in any cluster, as it uses remote access
450 * primitives when the FAT mapper is remote. It takes the queuelock stored in the FATFS
451 * context located in the same cluster as the FAT mapper itself, to get exclusive
452 * access to the FAT. It uses and updates the <free_cluster_hint> and <free_clusters>
453 * variables stored in this FATFS context.
454 * - it updates the <free_cluster_hint> and <free_clusters> variables in FATFS context.
455 * - it updates the FAT mapper (handling miss from IOC device if required).
456 * - it synchronously updates the FAT region on IOC device.
457 * - it returns the allocated cluster index.
458 *****************************************************************************************
459 * @ searched_cluster    : [out] found FATFS cluster index.
460 * @ return 0 if success / return -1 if no more free clusters on IOC device.
461 ****************************************************************************************/
462error_t fatfs_cluster_alloc( uint32_t * searched_cluster );
463
464/*****************************************************************************************
465 * This function implements the generic vfs_fs_release_inode() function for the FATFS.
466  *****************************************************************************************
467 * It releases all clusters allocated to a file/directory identified by the <inode_xp>
468 * argument. All released clusters are marked FREE_CLUSTER in the FAT mapper.
469 * This function calls the recursive function fatfs_cluster_release() to release
470 * the clusters in reverse order of the linked list (from last to first).
471 * When the FAT mapper has been updated, it calls the fatfs_sync_fat() function to
472 * synchronously update all dirty pages in the FAT mapper to the IOC device.
473 * Finally the FS-INFO sector on the IOC device is updated.
474 *****************************************************************************************
475 * @ inode_xp   : extended pointer on inode.
476 * @ return 0 if success / return EIO if failure during device access.
477 ****************************************************************************************/
478error_t fatfs_release_inode( xptr_t inode_xp );
479
480/*****************************************************************************************
481 * This function implements the generic vfs_fs_move_page() function for the FATFS.
482 *****************************************************************************************
483 * This function moves a page from/to the mapper to/from the FATFS file system on device.
484 * The page must have been previously allocated and registered in the mapper.   
485 * The pointer on the mapper and the page index in file are found in the page descriptor.
486 * It is used for both a regular file/directory mapper, and the FAT mapper.
487 * - For the FAT mapper, it updates the FAT region on IOC device.
488 * - For a regular file, it access the FAT mapper to get the cluster index on IOC device.
489 * It can be called by any thread running in any cluster.
490 *
491 * WARNING : For the FAT mapper, the inode field in the mapper MUST be NULL, as this
492 * is used to indicate that the corresponding mapper is the FAT mapper.
493 *****************************************************************************************
494 * @ page_xp   : extended pointer on page descriptor.
495 * @ cmd_type  : IOC_READ / IOC_WRITE / IOC_SYNC_READ / IOC_SYNC_WRITE
496 * @ return 0 if success / return EIO if error during device access.
497 ****************************************************************************************/
498error_t fatfs_move_page( xptr_t      page_xp,
499                         cmd_type_t  cmd_type );
500
501
502
503
504
505
506#endif  /* _FATFS_H_ */
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