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source: trunk/kernel/vfs/fatfs.c @ 249

Last change on this file since 249 was 246, checked in by alain, 7 years ago
Fix a major bug in FATFS : miss handling in the FAT mapper.
File size: 27.1 KB

Line
1	/*
2	* fatfs.c - FATFS file system API implementation.
3	*
4	* Author Alain Greiner (2016,2017)
5	*
6	* Copyright (c) UPMC Sorbonne Universites
7	*
8	* This file is part of ALMOS-MKH.
9	*
10	* ALMOS-MKH is free software; you can redistribute it and/or modify it
11	* under the terms of the GNU General Public License as published by
12	* the Free Software Foundation; version 2.0 of the License.
13	*
14	* ALMOS-MKH is distributed in the hope that it will be useful, but
15	* WITHOUT ANY WARRANTY; without even the implied warranty of
16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17	* General Public License for more details.
18	*
19	* You should have received a copy of the GNU General Public License
20	* along with ALMOS-MKH; if not, write to the Free Software Foundation,
21	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22	*/
23
24
25	#include <hal_types.h>
26	#include <hal_special.h>
27	#include <printk.h>
28	#include <kmem.h>
29	#include <ppm.h>
30	#include <vfs.h>
31	#include <string.h>
32	#include <rpc.h>
33	#include <mapper.h>
34	#include <cluster.h>
35	#include <dev_ioc.h>
36	#include <fatfs.h>
37
38
39	//////////////////////////////////////////////////////////////////////////////////////////
40	// Extern variables
41	//////////////////////////////////////////////////////////////////////////////////////////
42
43	extern vfs_ctx_t fs_context[FS_TYPES_NR]; // allocated in vfs.c file
44
45	extern remote_barrier_t global_barrier; // allocated in kernel_init.c
46
47	//////////////////////////////////////////////////////////////////////////////////////////
48	// FATFS private and static functions
49	//////////////////////////////////////////////////////////////////////////////////////////
50
51	//////////////////////////////////////////////////////////////////////////////////////////
52	// These functions return the "offset" and "length" values of an
53	// [offset,length] constant defined in the fatfs.h file.
54	//////////////////////////////////////////////////////////////////////////////////////////
55
56	static inline int get_length( int offset , int length ) { return length; }
57
58	static inline int get_offset( int offset , int length ) { return offset; }
59
60
61	//////////////////////////////////////////////////////////////////////////////////////////
62	// This function returns the LBA of the first sector of a FAT cluster.
63	// This function can be called by any thread running in any cluster.
64	//////////////////////////////////////////////////////////////////////////////////////////
65	// @ ctx : pointer on FATFS context.
66	// @ cluster : cluster index in FATFS.
67	// @ return the lba value.
68	//////////////////////////////////////////////////////////////////////////////////////////
69	static inline uint32_t fatfs_lba_from_cluster( fatfs_ctx_t * ctx,
70	uint32_t cluster )
71	{
72	return (ctx->cluster_begin_lba + ((cluster - 2) << 3));
73	}
74
75	//////////////////////////////////////////////////////////////////////////////////////////
76	// This function display the content of the FATFS context.
77	//////////////////////////////////////////////////////////////////////////////////////////
78	void fatfs_ctx_display()
79	{
80	uint32_t type = FS_TYPE_FATFS;
81	vfs_ctx_t * vfs_ctx = &fs_context[FS_TYPE_FATFS];
82	fatfs_ctx_t * fatfs_ctx = (fatfs_ctx_t *)vfs_ctx->extend;
83
84	printk("\n* FAT context *\n"
85	"- fat_sectors = %d\n"
86	"- sector size = %d\n"
87	"- cluster size = %d\n"
88	"- fat_first_lba = %d\n"
89	"- data_first_lba = %d\n"
90	"- root_dir_cluster = %d\n"
91	"- mapper_xp = %l\n",
92	fatfs_ctx->fat_sectors_count,
93	fatfs_ctx->bytes_per_sector,
94	fatfs_ctx->sectors_per_cluster * fatfs_ctx->bytes_per_sector,
95	fatfs_ctx->fat_begin_lba,
96	fatfs_ctx->cluster_begin_lba,
97	fatfs_ctx->root_dir_cluster,
98	fatfs_ctx->fat_mapper_xp );
99	}
100
101	//////////////////////////////////////////////////////////////////////////////////////////
102	// This function return an integer record value (one, two, or four bytes)
103	// from a memory buffer, taking into account endianness.
104	//////////////////////////////////////////////////////////////////////////////////////////
105	// @ offset : first byte of record in buffer.
106	// @ size : record length in bytes (1/2/4).
107	// @ buffer : pointer on buffer base.
108	// @ little endian : the most significant byte has the highest address when true.
109	// @ return the integer value in a 32 bits word.
110	//////////////////////////////////////////////////////////////////////////////////////////
111	static uint32_t fatfs_get_record( uint32_t offset,
112	uint32_t size,
113	uint8_t * buffer,
114	uint32_t little_endian )
115	{
116	uint32_t n;
117	uint32_t res = 0;
118
119	if ( little_endian)
120	{
121	for( n = size ; n > 0 ; n-- ) res = (res<<8) \| buffer[offset+n-1];
122	}
123	else
124	{
125	for( n = 0 ; n < size ; n++ ) res = (res<<8) \| buffer[offset+n];
126	}
127	return res;
128
129	} // end fatfs_get_record()
130
131	//////////////////////////////////////////////////////////////////////////////////////////
132	// This static function retun in the <name> buffer a short name stored in
133	// a SFN FATFS directory entry.
134	/////////////////////////i////////////////////////////////////////////////////////////////
135	// @ buffer : pointer on buffer containing the directory entry.
136	// @ name : [out] buffer allocated by the caller.
137	//////////////////////////////////////////////////////////////////////////////////////////
138	static void fatfs_get_name_from_short( uint8_t * buffer,
139	char * name )
140	{
141	uint32_t i;
142	uint32_t j = 0;
143
144	// get name
145	for ( i = 0; i < 8 && buffer[i] != ' '; i++ )
146	{
147	name[j] = to_lower( buffer[i] );
148	j++;
149	}
150
151	// get extension
152	for ( i = 8; i < 8 + 3 && buffer[i] != ' '; i++ )
153	{
154	// we entered the loop so there is an extension. add the dot
155	if ( i == 8 )
156	{
157	name[j] = '.';
158	j++;
159	}
160
161	name[j] = to_lower( buffer[i] );
162	j++;
163	}
164
165	name[j] = '\0';
166	}
167
168	//////////////////////////////////////////////////////////////////////////////////////////
169	// This static function retun in the <name> buffer a partial name stored in
170	// a LFN FATFS directory entry.
171	/////////////////////////i////////////////////////////////////////////////////////////////
172	// @ buffer : pointer on buffer containing the directory entry.
173	// @ name : [out] buffer allocated by the caller.
174	//////////////////////////////////////////////////////////////////////////////////////////
175	static void fatfs_get_name_from_long( uint8_t * buffer,
176	char * name )
177	{
178	uint32_t name_offset = 0;
179	uint32_t buffer_offset = get_length(LDIR_ORD);
180	uint32_t l_name_1 = get_length(LDIR_NAME_1);
181	uint32_t l_name_2 = get_length(LDIR_NAME_2);
182	uint32_t l_name_3 = get_length(LDIR_NAME_3);
183	uint32_t l_attr = get_length(LDIR_ATTR);
184	uint32_t l_type = get_length(LDIR_TYPE);
185	uint32_t l_chksum = get_length(LDIR_CHKSUM);
186	uint32_t l_rsvd = get_length(LDIR_RSVD);
187
188	uint32_t j = 0;
189	uint32_t eof = 0;
190
191	while ( (buffer_offset != DIR_ENTRY_SIZE) && (!eof) )
192	{
193	while (j != l_name_1 && !eof )
194	{
195	if ( (buffer[buffer_offset] == 0x00) \|\|
196	(buffer[buffer_offset] == 0xFF) )
197	{
198	eof = 1;
199	continue;
200	}
201	name[name_offset] = buffer[buffer_offset];
202	buffer_offset += 2;
203	j += 2;
204	name_offset++;
205	}
206
207	buffer_offset += (l_attr + l_type + l_chksum);
208	j = 0;
209
210	while (j != l_name_2 && !eof )
211	{
212	if ( (buffer[buffer_offset] == 0x00) \|\|
213	(buffer[buffer_offset] == 0xFF) )
214	{
215	eof = 1;
216	continue;
217	}
218	name[name_offset] = buffer[buffer_offset];
219	buffer_offset += 2;
220	j += 2;
221	name_offset++;
222	}
223
224	buffer_offset += l_rsvd;
225	j = 0;
226
227	while (j != l_name_3 && !eof )
228	{
229	if ( (buffer[buffer_offset] == 0x00) \|\|
230	(buffer[buffer_offset] == 0xFF) )
231	{
232	eof = 1;
233	continue;
234	}
235	name[name_offset] = buffer[buffer_offset];
236	buffer_offset += 2;
237	j += 2;
238	name_offset++;
239	}
240	}
241	name[name_offset] = 0;
242
243	} // end get_name_from_long()
244
245	//////////////////////////////////////////////////////////////////////////////////////////
246	// This function returns the FATFS cluster index of a page identified by its page
247	// index in the file, using the FAT mapper. It scans the FAT mapper, starting from the
248	// FATFS cluster index allocated to the first page of the file, until it reaches the
249	// searched page. The FAT mapper is automatically updated in case of miss.
250	// This function can be called by any thread running in any cluster, as it uses the
251	// RPC_FATFS_GET_CLUSTER to access the remote FAT mapper if required.
252	// We use a RPC to scan the FAT because the RPC_FIFO will avoid contention
253	// in the cluster containing the FAT mapper, and the RPC latency is not critical
254	// compared to the device access latency.
255	//////////////////////////////////////////////////////////////////////////////////////////
256	// @ ctx : pointer on local FATFS context.
257	// @ first_cluster : first cluster allocated to a file in FATFS.
258	// @ page_index : index of searched page in file (one page occupies one cluster).
259	// @ cluster_index : [out] pointer on buffer for FATFS cluster index.
260	// @ return 0 if success / return EIO if a FAT cluster miss cannot be solved.
261	//////////////////////////////////////////////////////////////////////////////////////////
262	static error_t fatfs_cluster_from_index( fatfs_ctx_t * ctx,
263	uint32_t first_cluster,
264	uint32_t page_index,
265	uint32_t * cluster_index )
266	{
267	uint32_t searched_cluster; // searched FATFS cluster index
268	error_t error;
269
270	// get extended pointer on FAT mapper
271	xptr_t fat_mapper_xp = ctx->fat_mapper_xp;
272
273	// get cluster cxy and local pointer on FAT mapper
274	cxy_t fat_mapper_cxy = GET_CXY( fat_mapper_xp );
275	mapper_t * fat_mapper_ptr = (mapper_t *)GET_PTR( fat_mapper_xp );
276
277	if( fat_mapper_cxy == local_cxy ) // FAT mapper is local
278	{
279	error = fatfs_get_cluster( fat_mapper_ptr,
280	first_cluster,
281	page_index,
282	&searched_cluster );
283	}
284	else // FAT mapper is remote
285	{
286	rpc_fatfs_get_cluster_client( fat_mapper_cxy,
287	fat_mapper_ptr,
288	first_cluster,
289	page_index,
290	&searched_cluster,
291	&error );
292	}
293
294	if( error )
295	{
296	printk("\n[ERROR] in %s : cannot access FAT\n", __FUNCTION__ );
297	return error;
298	}
299
300	// return success
301	*cluster_index = searched_cluster;
302	return 0;
303
304	} // end fatfs_cluster_from_index()
305
306	//////////////////////////////////////////////////////////////////////////////////////////
307	// FATFS specific but extern function (used by RPC_FATFS_GET_CLUSTER)
308	//////////////////////////////////////////////////////////////////////////////////////////
309
310	/////////////////////////////////////////////
311	error_t fatfs_get_cluster( mapper_t * mapper,
312	uint32_t first_cluster,
313	uint32_t searched_page,
314	uint32_t * cluster )
315	{
316	page_t * current_page_desc; // pointer on current page descriptor
317	uint32_t * current_page_buffer; // pointer on current page (array of uint32_t)
318	uint32_t current_page_index; // index of current page in mapper
319	uint32_t current_page_offset; // offset of slot in current page
320	uint32_t page_count_in_file; // index of page in file (index in linked list)
321	uint32_t current_cluster; // content of current FAT slot
322
323	fatfs_dmsg("\n[INFO] %s : enters / first_cluster_id = %d / searched_page = %d\n",
324	__FUNCTION__ , first_cluster , searched_page );
325
326	#if CONFIG_FATFS_DEBUG
327	uint32_t * buf = (uint32_t *)ppm_page2vaddr( mapper_get_page ( mapper , 0 ) );
328	uint32_t line , word;
329	printk("\n* FAT content for first 128 entries *\n");
330	for( line = 0 ; line < 8 ; line++ )
331	{
332	printk("%d : ");
333	for( word = 0 ; word < 16 ; word++ ) printk("%X ", buf[(line<<4) + word] );
334	printk("\n");
335	}
336	#endif
337
338	// compute number of FAT slots per page
339	uint32_t slots_per_page = CONFIG_PPM_PAGE_SIZE >> 2;
340
341	// initialize loop variable
342	current_page_index = first_cluster / slots_per_page;
343	current_page_offset = first_cluster % slots_per_page;
344	page_count_in_file = 0;
345
346	// scan FAT (i.e. traverse FAT linked list)
347	while( page_count_in_file <= searched_page )
348	{
349
350	fatfs_dmsg("\n[INFO] %s : page_index = %d / page_offset = %d / count = %d\n",
351	__FUNCTION__ , current_page_index , current_page_offset , page_count_in_file );
352
353	// get pointer on current page descriptor
354	current_page_desc = mapper_get_page( mapper , current_page_index );
355
356	if( current_page_desc == NULL ) return EIO;
357
358	// get pointer on buffer for current page
359	current_page_buffer = (uint32_t *)ppm_page2vaddr( current_page_desc );
360
361	// get FAT slot content
362	current_cluster = current_page_buffer[current_page_offset];
363
364	// update loop variables
365	current_page_index = current_cluster / slots_per_page;
366	current_page_offset = current_cluster % slots_per_page;
367	page_count_in_file++;
368	}
369
370	fatfs_dmsg("\n[INFO] %s : exit / cluster_id = %d\n",
371	__FUNCTION__ , current_cluster );
372
373	*cluster = current_cluster;
374	return 0;
375
376	} // end fatfs_get_cluster()
377
378
379
380	///////////////////////////////////////////////////////////////////////////////////////
381	// Generic API : the following functions are called by the kernel (VFS)
382	// and must be defined by all supported file systems.
383	///////////////////////////////////////////////////////////////////////////////////////
384
385	///////////////////////////////
386	fatfs_ctx_t * fatfs_ctx_alloc()
387	{
388	kmem_req_t req;
389	req.type = KMEM_FATFS_CTX;
390	req.size = sizeof(fatfs_ctx_t);
391	req.flags = AF_KERNEL \| AF_ZERO;
392
393	return (fatfs_ctx_t *)kmem_alloc( &req );
394	}
395
396	//////////////////////////////////////////////
397	void fatfs_ctx_init( fatfs_ctx_t * fatfs_ctx )
398	{
399	error_t error;
400	kmem_req_t req;
401	uint8_t * buffer;
402
403	fatfs_dmsg("\n[INFO] %s : enters for fatfs_ctx = %x\n",
404	__FUNCTION__ , fatfs_ctx );
405
406	assert( (fatfs_ctx != NULL) , __FUNCTION__ ,
407	"cannot allocate memory for FATFS context\n" );
408
409	// allocate a 512 bytes buffer to store the boot record
410	req.type = KMEM_512_BYTES;
411	req.flags = AF_KERNEL \| AF_ZERO;
412	buffer = (uint8_t *)kmem_alloc( &req );
413
414	assert( (buffer != NULL) , __FUNCTION__ ,
415	"cannot allocate memory for 512 bytes buffer\n" );
416
417	// load the boot record from device
418	// using a synchronous access to IOC device
419	error = dev_ioc_sync_read( buffer , 0 , 1 );
420
421	assert( (error == 0) , __FUNCTION__ ,
422	"cannot access boot record\n" );
423
424	#if (CONFIG_FATFS_DEBUG > 1)
425	uint32_t line;
426	uint32_t byte = 0;
427	printk("\n* boot record at cycle %d *\n", hal_get_cycles() );
428	for ( line = 0 ; line < 32 ; line++ )
429	{
430	printk(" %X \| %x %x %x %x %x %x %x %x %x %x %x %x %x %x %x %x \|\n",
431	byte,
432	buffer[byte+ 0],buffer[byte+ 1],buffer[byte+ 2],buffer[byte+ 3],
433	buffer[byte+ 4],buffer[byte+ 5],buffer[byte+ 6],buffer[byte+ 7],
434	buffer[byte+ 8],buffer[byte+ 9],buffer[byte+10],buffer[byte+11],
435	buffer[byte+12],buffer[byte+13],buffer[byte+14],buffer[byte+15] );
436
437	byte += 16;
438	}
439	#endif
440
441	// check sector size from boot record
442	uint32_t sector_size = fatfs_get_record( BPB_BYTSPERSEC , buffer , 1 );
443
444	nolock_assert( (sector_size == 512) , __FUNCTION__ ,
445	"sector size must be 512 bytes\n" );
446
447	// check cluster size from boot record
448	uint32_t nb_sectors = fatfs_get_record( BPB_SECPERCLUS , buffer , 1 );
449
450	nolock_assert( (nb_sectors == 8) , __FUNCTION__ ,
451	"cluster size must be 8 sectors\n" );
452
453	// check number of FAT copies from boot record
454	uint32_t nb_fats = fatfs_get_record( BPB_NUMFATS , buffer , 1 );
455
456	nolock_assert( (nb_fats == 1) , __FUNCTION__ ,
457	"number of FAT copies must be 1\n" );
458
459	// get & check number of sectors in FAT from boot record
460	uint32_t fat_sectors = fatfs_get_record( BPB_FAT32_FATSZ32 , buffer , 1 );
461
462	nolock_assert( ((fat_sectors & 0xF) == 0) , __FUNCTION__ ,
463	"FAT not multiple of 16 sectors\n");
464
465	// get and check root cluster from boot record
466	uint32_t root_cluster = fatfs_get_record( BPB_FAT32_ROOTCLUS , buffer , 1 );
467
468	nolock_assert( (root_cluster == 2) , __FUNCTION__ ,
469	"root cluster index must be 2\n");
470
471	// get FAT lba from boot record
472	uint32_t fat_lba = fatfs_get_record( BPB_RSVDSECCNT , buffer , 1 );
473
474	// release the 512 bytes buffer
475	req.type = KMEM_512_BYTES;
476	req.ptr = buffer;
477	kmem_free( &req );
478
479	// allocate a mapper for the FAT itself
480	mapper_t * fat_mapper = mapper_create( FS_TYPE_FATFS );
481
482	assert( (fat_mapper != NULL) , __FUNCTION__ , "no memory for FAT mapper" );
483
484	// WARNING : the inode field MUST be NULL for the FAT mapper
485	fat_mapper->inode = NULL;
486
487	// initialize the FATFS context
488	fatfs_ctx->fat_begin_lba = fat_lba;
489	fatfs_ctx->fat_sectors_count = fat_sectors;
490	fatfs_ctx->bytes_per_sector = sector_size;
491	fatfs_ctx->sectors_per_cluster = nb_sectors;
492	fatfs_ctx->cluster_begin_lba = fat_lba + fat_sectors;
493	fatfs_ctx->root_dir_cluster = 2;
494	fatfs_ctx->last_allocated_sector = 0; // TODO ???
495	fatfs_ctx->last_allocated_index = 0; // TODO ???
496	fatfs_ctx->fat_mapper_xp = XPTR( local_cxy , fat_mapper );
497
498	} // end fatfs_ctx_init()
499
500	/////////////////////////////////////////////////
501	void fatfs_ctx_destroy( fatfs_ctx_t * fatfs_ctx )
502	{
503	kmem_req_t req;
504	req.type = KMEM_FATFS_CTX;
505	req.ptr = fatfs_ctx;
506	kmem_free( &req );
507	}
508
509	//////////////////////////////////////////////
510	error_t fatfs_mapper_move_page( page_t * page,
511	bool_t to_mapper )
512	{
513	error_t error;
514
515	// get pointer on source mapper and page index from page descriptor
516	mapper_t * mapper = page->mapper;
517	uint32_t index = page->index;
518
519	// get VFS inode pointer from mapper
520	vfs_inode_t * inode = mapper->inode;
521
522	fatfs_dmsg("\n[INFO] %s : enter for inode %x / page_index = %d / mapper = %x\n",
523	__FUNCTION__ , inode , index , mapper );
524
525	// get memory buffer base address
526	uint8_t * buffer = (uint8_t *)ppm_page2vaddr( page );
527
528	// get number of sectors from FATFS context
529	fatfs_ctx_t * fatfs_ctx = (fatfs_ctx_t *)fs_context[FS_TYPE_FATFS].extend;
530	uint32_t count = fatfs_ctx->sectors_per_cluster;
531
532	// analyse the mapper type : FAT or normal inode
533	if( inode == NULL ) // it is the FAT mapper
534	{
535	// get lba from page index
536	uint32_t lba = fatfs_ctx->fat_begin_lba + (count * index);
537
538	fatfs_dmsg("\n[INFO] %s : for FAT / lba = %d\n",
539	__FUNCTION__ , lba );
540
541	// access device
542	if( to_mapper ) error = dev_ioc_sync_read ( buffer , lba , count );
543	else error = dev_ioc_write( buffer , lba , count );
544
545	if( error ) return EIO;
546
547	fatfs_dmsg("\n[INFO] %s : exit for FAT / page_index = %d / mapper = %x\n",
548	__FUNCTION__ , index , mapper );
549	}
550	else // it is a normal inode mapper
551	{
552	// get first cluster index from inode extension
553	uint32_t first_cluster = (uint32_t)(intptr_t)inode->extend;
554
555	fatfs_dmsg("\n[INFO] %s : for inode %x / first cluster_id = %d\n",
556	__FUNCTION__ , inode , first_cluster );
557
558	// compute FATFS_cluster index for the accessed page
559	uint32_t cluster = 0;
560	error_t error = fatfs_cluster_from_index( fatfs_ctx,
561	first_cluster,
562	index,
563	&cluster );
564	if( error ) return EIO;
565
566	// get lba from cluster
567	uint32_t lba = fatfs_lba_from_cluster( fatfs_ctx , cluster );
568
569	fatfs_dmsg("\n[INFO] %s : for inode %x / page = %d / cluster_id = %d / lba = %x\n",
570	__FUNCTION__ , inode , index , cluster , lba );
571
572	// access device
573	if( to_mapper ) error = dev_ioc_sync_read ( buffer , lba , count );
574	else error = dev_ioc_write( buffer , lba , count );
575
576	if( error ) return EIO;
577
578	fatfs_dmsg("\n[INFO] %s : exit for inode %x / page = %x / mapper = %x\n",
579	__FUNCTION__ , inode , page , mapper );
580	}
581
582	return 0;
583
584	} // end fatfs_mapper_move_page()
585
586	/////////////////////////////////////////////////////////////////
587	error_t fatfs_inode_load( vfs_inode_t * parent_inode,
588	char * name,
589	xptr_t child_inode_xp )
590	{
591	// Two embedded loops:
592	// - scan the parent mapper pages
593	// - scan the directory entries in each 4 Kbytes page
594
595	fatfs_dmsg("\n[INFO] %s : enter for child <%s> in parent inode %l\n",
596	__FUNCTION__ , name , XPTR( local_cxy , parent_inode ) );
597
598	mapper_t * mapper = parent_inode->mapper;
599
600	assert( (mapper != NULL) , __FUNCTION__ , "parent mapper undefined\n");
601
602	char cname[CONFIG_VFS_MAX_NAME_LENGTH]; // name extracter from each directory entry
603
604	char lfn1[16]; // buffer for one partial cname
605	char lfn2[16]; // buffer for one partial cname
606	char lfn3[16]; // buffer for one partial cname
607	page_t * page; // pointer on current page descriptor
608	uint8_t * base; // pointer on current page base
609	uint32_t offset = 0; // byte offset in page
610	uint32_t index = 0; // page index in mapper
611	uint32_t attr; // directory entry ATTR field
612	uint32_t ord; // directory entry ORD field
613	uint32_t seq; // sequence index
614	uint32_t lfn = 0; // LFN entries number
615	uint32_t size = 0; // searched file/dir size (bytes)
616	uint32_t cluster = 0; // searched file/dir cluster index
617	uint32_t is_dir = 0; // searched file/dir type
618	uint32_t dentry; // directory entry index
619	int32_t found = 0; // not found (0) / name found (1) / end of dir (-1)
620
621	// scan the parent directory mapper
622	while ( found == 0 )
623	{
624	// get one page
625	page = mapper_get_page( mapper , index );
626
627	assert( (page != NULL) , __FUNCTION__ , "bad parent mapper\n");
628
629	// get page base
630	base = ppm_page2vaddr( page );
631
632	// scan this page until end of directory, end of page, or name found
633	while( (offset < 4096) && (found == 0) )
634	{
635	attr = fatfs_get_record( DIR_ATTR , base + offset , 0 );
636	ord = fatfs_get_record( LDIR_ORD , base + offset , 0 );
637
638	if (ord == NO_MORE_ENTRY) // no more entry => break
639	{
640	found = -1;
641	}
642	else if ( ord == FREE_ENTRY ) // free entry => skip
643	{
644	offset = offset + 32;
645	}
646	else if ( attr == ATTR_LONG_NAME_MASK ) // LFN entry => get partial cname
647	{
648	seq = ord & 0x3;
649	lfn = (seq > lfn) ? seq : lfn;
650	if ( seq == 1 ) fatfs_get_name_from_long( base + offset, lfn1 );
651	else if ( seq == 2 ) fatfs_get_name_from_long( base + offset, lfn2 );
652	else if ( seq == 3 ) fatfs_get_name_from_long( base + offset, lfn3 );
653	offset = offset + 32;
654	}
655	else // NORMAL entry
656	{
657	// build the extracted name
658	if ( lfn == 0 )
659	{
660	fatfs_get_name_from_short( base + offset , cname );
661	}
662	else if ( lfn == 1 )
663	{
664	strcpy( cname , lfn1 );
665	}
666	else if ( lfn == 2 )
667	{
668	strcpy( cname , lfn1 );
669	strcpy( cname + 13 , lfn2 );
670	}
671	else if ( lfn == 3 )
672	{
673	strcpy( cname , lfn1 );
674	strcpy( cname + 13 , lfn2 );
675	strcpy( cname + 26 , lfn3 );
676	}
677
678	// get dentry arguments if extracted cname == searched name
679	if ( strcmp( name , cname ) == 0 )
680	{
681	cluster = (fatfs_get_record( DIR_FST_CLUS_HI , base + offset , 1 ) << 16) \|
682	(fatfs_get_record( DIR_FST_CLUS_LO , base + offset , 1 ) ) ;
683	dentry = ((index<<12) + offset)>>5;
684	is_dir = ((attr & ATTR_DIRECTORY) == ATTR_DIRECTORY);
685	size = fatfs_get_record( DIR_FILE_SIZE , base + offset , 1 );
686	found = 1;
687	}
688	offset = offset + 32;
689	lfn = 0;
690	}
691	} // end loop on directory entries
692	index++;
693	offset = 0;
694	} // end loop on pages
695
696	// analyse the result of scan
697
698	if ( found == -1 ) // found end of directory => failure
699	{
700	fatfs_dmsg("\n[INFO] %s : exit / child <%s> not found in parent inode %l\n",
701	__FUNCTION__ , name , XPTR( local_cxy , parent_inode ) );
702
703	return ENOENT;
704	}
705	else // found searched child name
706	{
707	// get child inode cluster and local pointer
708	cxy_t child_cxy = GET_CXY( child_inode_xp );
709	vfs_inode_t * child_ptr = (vfs_inode_t *)GET_PTR( child_inode_xp );
710
711	// update the child inode "type", "size", and "extend" fields
712	vfs_inode_type_t type = (is_dir) ? INODE_TYPE_DIR : INODE_TYPE_FILE;
713
714	hal_remote_sw( XPTR( child_cxy , &child_ptr->type ) , type );
715	hal_remote_sw( XPTR( child_cxy , &child_ptr->size ) , size );
716	hal_remote_sw( XPTR( child_cxy , &child_ptr->extend ) , cluster );
717
718	fatfs_dmsg("\n[INFO] %s : exit / child <%s> found in parent inode %l\n",
719	__FUNCTION__ , name , XPTR( local_cxy , parent_inode ) );
720
721	return 0;
722	}
723	} // end fatfs_inode_load()

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