source: trunk/kernel/fs/vfs.h @ 679

Last change on this file since 679 was 673, checked in by alain, 4 years ago

Introduce the DEBUG_VFS_ERROR in kernel_config to make
error messges display conditional.

File size: 61.0 KB
Line 
1/*
2 * vfs.h - Virtual File System definition.
3 *
4 * Author  Mohamed Lamine Karaoui (2014,2015)
5 *         Alain Greiner          (2016,2017,2018,2019,2020)
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 _VFS_H_
26#define _VFS_H_
27
28#include <kernel_config.h>
29#include <hal_kernel_types.h>
30#include <hal_atomic.h>
31#include <remote_rwlock.h>
32#include <remote_busylock.h>
33#include <busylock.h>
34#include <list.h>
35#include <xlist.h>
36#include <bits.h>
37#include <xhtab.h>
38#include <errno.h>
39#include <shared_syscalls.h>
40#include <fatfs.h>
41#include <ramfs.h>
42#include <devfs.h>
43#include <dev_ioc.h>
44
45/****  Forward declarations  ***/
46
47struct vfs_inode_s;
48struct vfs_dentry_s;
49struct vfs_ctx_s;
50struct vfs_file_s;
51struct remote_buf_s;
52struct mapper_s;
53struct process_s;
54struct device_s;
55struct vseg_s;
56struct page_s;
57struct ksock_s;
58
59/******************************************************************************************
60 * These flags are used to define the working mode of the vfs_lookup() function. 
61 *****************************************************************************************/
62
63#define VFS_LOOKUP_DIR      0x01     /* the searched inode must be a directory           */
64#define VFS_LOOKUP_OPEN         0x02     /* the search is for an open/opendir                */
65#define VFS_LOOKUP_PARENT       0x04     /* return the parent inode (not the inode itself)   */
66#define VFS_LOOKUP_CREATE   0x10     /* file must be created if missing                  */
67#define VFS_LOOKUP_EXCL     0x20     /* file cannot previously exist                     */
68
69
70
71
72/******************************************************************************************
73 * This structure defines a VFS context, that contains informations common to all inodes
74 * and dentries for a given file system. As it is declared as a global variable in the
75 * kdata segment (fs_context[] array), it is replicated in all clusters.
76 * The <extend> field is a pointer on the FS specific context extension.
77 * This extension is dynamically allocated by kernel_init in all clusters.
78 * In each cluster, the inum allocator can be accessed by any thread runing
79 * in any cluster, and is therefore protected by a remote_busylock.
80 *****************************************************************************************/
81
82typedef enum
83{
84        FS_TYPE_RAMFS = 0,
85        FS_TYPE_DEVFS = 1,
86        FS_TYPE_FATFS = 2,
87 
88        FS_TYPES_NR   = 3,
89}
90vfs_fs_type_t;
91
92typedef enum
93{
94    CTX_ATTR_READ_ONLY    = 0x01,            /*! write access prohibited                 */
95    CTX_ATTR_SYNC         = 0x10,            /*! synchronise FS on each write            */
96}
97vfs_ctx_attr_t;
98
99typedef struct vfs_ctx_s
100{
101        vfs_fs_type_t      type;                 /*! File System type                        */
102        uint32_t           total_clusters;       /*! total number of clusters on device      */
103        uint32_t           cluster_size;         /*! cluster size on device (bytes)          */
104        xptr_t             vfs_root_xp;          /*! extended pointer on VFS root inode      */
105    remote_busylock_t  lock;                 /*! lock protecting inum allocator          */
106    uint32_t           bitmap[BITMAP_SIZE(CONFIG_VFS_MAX_INODES)];  /* inum allocator    */
107    void               * extend;             /*! FS specific context extension           */
108}
109vfs_ctx_t;
110
111/******************************************************************************************
112 *        These functions access / modify  a VFS context.
113 *****************************************************************************************/
114
115/******************************************************************************************
116 * This function initialises a (statically allocated) VFS context in cluster identified
117 * by the <cxy> argument.
118 * It is called by the kernel_init() function.
119 ******************************************************************************************
120 * @ cxy            : target cluster identifier.
121 * @ fs_type        : file system type.
122 * @ total_clusters : total number of clusters on device.
123 * @ cluster_size   : cluster size on device (bytes).
124 * @ vfs_root_xp    : extended pointer on VFS root inode.
125 * @ extend         : fs_type_specific extension.
126 *****************************************************************************************/
127void vfs_ctx_init( cxy_t           cxy,
128                   vfs_fs_type_t   type,
129                       uint32_t        total_clusters,
130                       uint32_t        cluster_size,
131                       xptr_t          vfs_root_xp,
132                   void          * extend );
133
134/******************************************************************************************
135 * This function allocates an inode identifier from the local cluster inum allocator.
136 * The inum respects a fixed format:
137 * - the 16 MSB bits contain the cluster identifier : cxy
138 * - the 16 LSB bits contains the local inode identifier  : lid
139 ******************************************************************************************
140 * @ ctx_xp   : [in]  extended pointer on file system context.
141 * @ inum     : [out] buffer for allocated inode identifier.
142 * @ return 0 if success / return non-zero if error.
143 *****************************************************************************************/
144error_t vfs_ctx_inum_alloc( xptr_t     ctx_xp,
145                            uint32_t * inum );
146
147/******************************************************************************************
148 * This function release an inode identifier.                                 
149 ******************************************************************************************
150 * @ ctx_xp   : [in] extended pointer on file system context.
151 * @ inum     : [in] released inode identifier.
152 *****************************************************************************************/
153void vfs_ctx_inum_release( xptr_t      ctx_xp,
154                           uint32_t    inum );
155
156
157
158
159
160
161/******************************************************************************************
162 * This file structure describes an open file/directory for a given process.
163 * It is not replicated, and is dynamically allocated in the cluster that contains
164 * the associated inode / socket / pipe , when a thread makes an open(), opendir(),
165 * socket(), or pipe() system call. It cannot exist a <file> structure without a
166 * a <mapper>, <socket>, or <pipe> structure (depending on type) in same cluster.
167 * It can exist a <file> structure without an <inode> (for PIPE and SOCK types).
168 *****************************************************************************************/
169
170/* this enum define the VFS inode types values                                           */
171/* WARNING : this enum must be kept consistent with macros in <shared_stat.h> file       */
172/*           and with types in <shared_dirent.h> file.                                   */
173
174typedef enum   
175{
176    FILE_TYPE_REG   =     0,           /*! regular file                                 */
177    FILE_TYPE_DIR   =     1,           /*! directory                                    */
178    FILE_TYPE_FIFO  =     2,           /*! POSIX named fifo                             */
179    FILE_TYPE_PIPE  =     3,           /*! POSIX anonymous pipe                         */
180    FILE_TYPE_SOCK  =     4,           /*! POSIX anonymous socket                       */
181    FILE_TYPE_DEV   =     5,           /*! character device                             */
182    FILE_TYPE_BLK   =     6,           /*! block device                                 */
183    FILE_TYPE_SYML  =     7,           /*! symbolic link                                */
184}
185vfs_file_type_t;
186
187typedef enum
188{
189    FD_ATTR_READ_ENABLE    = 0x01,     /*! read access possible                          */
190    FD_ATTR_WRITE_ENABLE   = 0x02,     /*! write access possible                         */
191    FD_ATTR_APPEND         = 0x04,     /*! append on each write                          */
192    FD_ATTR_CLOSE_EXEC     = 0x08,     /*! close file on exec                            */
193    FD_ATTR_SYNC           = 0x10,     /*! synchronise FS on each write                  */
194    FD_ATTR_IS_DIR         = 0x20,     /*! this is a directory                           */
195}
196vfs_file_attr_t;
197
198typedef struct vfs_file_s
199{
200        struct vfs_ctx_s      * ctx;        /*! local pointer on FS context.                 */
201        vfs_file_attr_t         attr;       /*! file attributes bit vector (see above)       */
202        vfs_file_type_t        type;       /*! same type as inode                           */
203        uint32_t                offset;     /*! seek position in file                        */
204        remote_rwlock_t         lock;       /*! protect offset modifications                 */
205        struct vfs_inode_s    * inode;      /*! local pointer on associated inode            */
206        struct mapper_s       * mapper;     /*! associated mapper (REG or DIR types only)    */
207    struct socket_s       * socket;     /*! associated socket (SOCK type only)           */
208    struct pipe_s         * pipe;       /*! associated pipe (FIFO or PIPE types only)    */
209        void                  * extend;     /*! FS specific extension                        */
210}
211vfs_file_t;
212
213/******************************************************************************************
214 *        These low-level functions access / modify a VFS file descriptor
215 *****************************************************************************************/
216
217/******************************************************************************************
218 * This function allocates memory and initializes a new file descriptor in the
219 * cluster defined by the <inode_xp> argument.
220 * It can be called by any thread running in any cluster.
221 ******************************************************************************************
222 * @ inode_xp  : [in]  extended pointer on associated inode.
223 * @ attr      : [in]  file descriptor attributes.
224 * @ file_xp   : [out] buffer for extended pointer on created file descriptor.
225 * @ return 0 if success / return ENOMEM if error.
226 *****************************************************************************************/
227error_t vfs_file_create( xptr_t        inode_xp,
228                         uint32_t      attr,
229                         xptr_t      * file_xp ); 
230
231/******************************************************************************************
232 * This function releases memory allocated to file descriptor identified
233 * by the <file_xp> argument.
234 * It can be called by any thread running in any cluster.
235 ******************************************************************************************
236 * @ file_xp  : [in] extended pointer on file descriptor.
237 *****************************************************************************************/
238void vfs_file_destroy( xptr_t  file_xp ); 
239
240/******************************************************************************************
241 * This debug function copies the name of a the file identified by <file_xp>
242 * argument to a local buffer identified by the <name> argument.
243 * The local buffer size must be at least CONFIG_VFS_MAX_NAME_LENGTH.
244 *****************************************************************************************
245 * @ ionde_xp  : [in] extended pointer on the remote inode.
246 * @ name      : [out] local string.
247 ***************************************************************************************/
248void vfs_file_get_name( xptr_t inode_xp,
249                        char * name );
250
251
252
253
254/******************************************************************************************
255 * This structure define a VFS inode.
256 * An inode can have several children dentries (if it is a directory), an can have several
257 * parents dentries (if it has several aliases links):
258 * - The "parents" field is the root of the xlist of parents dentries, and the "links"
259 *   fiels define the number of aliases parent dentries. only a FILE inode can have
260 *   several parents (no hard links for directories).
261 * - The "children" field is an embedded xhtab containing pointers on all local children
262 *   dentries. This set of children is empty for a FILE inode.
263 * Synchronisation:
264 * - the main_lock (remote_rwlock) is used during the inode tree traversal,
265 *   or for inode modification (add/remove children in xhtab).
266 * - the size_lock (remote_rwlock) is used during read/write accesses to the size
267 *   field in the mapper.
268 * - access to the data stored in the associated mapper use the mapper remote_rwlock
269 *   protecting radix tree traversal and modifications.
270 *****************************************************************************************/
271
272/* this enum define the VFS inode attributes values */
273
274typedef enum 
275{
276    INODE_ATTR_DIRTY   =     0x01,       /*! modified versus the value on device         */ 
277    INODE_ATTR_INLOAD  =     0x04,       /*! loading from device in progress             */
278    INODE_ATTR_NEW     =     0x08,       /*! not saved on device yet                     */
279}
280vfs_inode_attr_t;
281
282typedef struct vfs_inode_s
283{
284    struct vfs_ctx_s    * ctx;           /*! local pointer on FS context                 */
285    uint32_t              inum;          /*! inode identifier (unique in file system)    */
286    uint32_t              attr;          /*! inode attributes (see above)                */
287    vfs_file_type_t      type;          /*! inode type (see above)                      */
288    uint32_t              size;          /*! number of bytes                             */
289    uint32_t              uid;           /*! user owner identifier                       */
290    uint32_t              gid;           /*! group owner identifier                      */
291    uint32_t              rights;        /*! access rights                               */
292    xlist_entry_t         parents;       /*! root of list of parents dentries            */
293    uint32_t              links;         /*! number of parent dentries (hard links)      */
294    xhtab_t               children;      /*! embedded xhtab of children dentries         */
295    remote_rwlock_t       size_lock;     /*! protect read/write to size                  */
296    remote_rwlock_t       main_lock;     /*! protect inode tree traversal and modifs     */
297    struct mapper_s     * mapper;        /*! associated file (REG or DIR types only)     */
298    struct remote_buf_s * pipe;          /*! associated pipe (FIFO type only)            */
299    void                * extend;        /*! fs_type_specific inode extension            */
300}
301vfs_inode_t;
302
303/* This define the masks for the inode <rights> field  */
304
305#define VFS_ISUID          0x0004000
306#define VFS_ISGID          0x0002000
307#define VFS_ISVTX          0x0001000
308
309#define VFS_IRWXU      0x0000700
310#define VFS_IRUSR      0x0000400
311#define VFS_IWUSR      0x0000200
312#define VFS_IXUSR      0x0000100
313
314#define VFS_IRWXG      0x0000070
315#define VFS_IRGRP      0x0000040
316#define VFS_IWGRP      0x0000020
317#define VFS_IXGRP      0x0000010
318
319#define VFS_IRWXO      0x0000007
320#define VFS_IROTH      0x0000004
321#define VFS_IWOTH      0x0000002
322#define VFS_IXOTH      0x0000001
323
324/******************************************************************************************
325 *        These low-level functions access / modify a VFS inode descriptor
326 *****************************************************************************************/
327
328/******************************************************************************************
329 * This function returns a printable string for the inode type.
330 *****************************************************************************************/
331const char * vfs_inode_type_str( vfs_file_type_t type );
332
333/******************************************************************************************
334 * This function allocates memory in cluster identified by the <cxy> argument
335 * for an inode descriptor and for the associated mapper, and partially initialise
336 * this inode from arguments values.
337 * It does NOT link it to the Inode Tree, as this is done by add_child_in_parent().
338 * It can be called by any thread running in any cluster.
339 ******************************************************************************************
340 * @ cxy        : [in]  target cluster identifier
341 * @ fs_type    : [in]  file system type.
342 * @ attr       : [in]  inode attributes.
343 * @ rights     : [in]  inode access rights.
344 * @ uid        : [in]  user owner ID.
345 * @ gid        : [in]  group owner ID.
346 * @ inode_xp   : [out] buffer for extended pointer on created inode.
347 * @ return 0 if success / return -1 if error.
348 *****************************************************************************************/
349error_t vfs_inode_create( cxy_t             cxy,
350                          vfs_fs_type_t     fs_type,
351                          uint32_t          attr,
352                          uint32_t          rights,
353                          uid_t             uid,
354                          gid_t             gid,
355                          xptr_t          * inode_xp );
356
357/******************************************************************************************
358 * This function releases memory allocated to an inode descriptor, including
359 * all memory allocated to the mapper (both mapper descriptor and radix tree).
360 * The mapper should not contain any dirty page (should be synchronized before deletion).
361 * It can be called by any thread running in any cluster.
362 ******************************************************************************************
363 * @ inode_xp  : extended pointer on inode descriptor.
364 *****************************************************************************************/
365void vfs_inode_destroy( xptr_t  inode_xp ); 
366
367/******************************************************************************************
368 * This function returns the <size> of a file/dir from a remote inode,
369 * taking the remote_rwlock protecting <size> in READ_MODE.
370 * It can be called by any thread running in any cluster.
371 *****************************************************************************************
372 * @ inode_xp  : extended pointer on the remote inode.
373 * @ return the current size.
374 *****************************************************************************************/
375uint32_t vfs_inode_get_size( xptr_t inode_xp );
376
377/******************************************************************************************
378 * This function updates the "size" field of a remote inode identified by <inode_xp>.
379 * It takes the rwlock protecting the file size in WRITE_MODE, and set the "size" field
380 * when the current size is smaller than the requested <size> argument.
381 * It can be called by any thread running in any cluster.
382 *****************************************************************************************
383 * @ inode_xp  : extended pointer on the remote inode.
384 * @ size      : requested size value.
385 *****************************************************************************************/
386void vfs_inode_update_size( xptr_t   inode_xp,
387                            uint32_t size );
388
389/******************************************************************************************
390 * This function takes the main lock of a remote inode identified by the <inode_xp>.
391 * This lock protect all inode fields, including the children dentries.
392 * It can be called by any thread running in any cluster.
393 *****************************************************************************************
394 * @ inode_xp  : extended pointer on the remote inode.
395 *****************************************************************************************/
396void vfs_inode_lock( xptr_t inode_xp );
397
398/******************************************************************************************
399 * This function releases the main lock of a remote inode identified by <inode_xp>.
400 * This lock protect all inode fiels, including the children dentries.
401 * It can be called by any thread running in any cluster.
402 *****************************************************************************************
403 * @ inode_xp  : extended pointer on the remote inode.
404 *****************************************************************************************/
405void vfs_inode_unlock( xptr_t inode_xp );
406
407/******************************************************************************************
408 * This debug function copies the name of a remote inode identified by the <inode_xp>
409 * argument to a local buffer identified by the <name> argument.
410 * The local buffer size must be at least CONFIG_VFS_MAX_NAME_LENGTH.
411 * It can be called by any thread running in any cluster.
412 ******************************************************************************************
413 * @ inode_xp  : extended pointer on the remote inode.
414 * @ name      : local buffer pointer.
415 *****************************************************************************************/
416void vfs_inode_get_name( xptr_t inode_xp,
417                         char * name );
418
419/******************************************************************************************
420 * This function accesses successively all pages of a file identified by the <inode_xp>,
421 * argument, to force misses, and load all pages into mapper.
422 * The target inode can be a directory or a file, but this function is mainly used
423 * to prefetch a complete directory to the mapper.
424 * This function does NOT take any lock.
425 * It can be called by any thread running in any cluster.
426 ******************************************************************************************
427 * @ inode_xp  : extended pointer on inode.
428 * @ return 0 if success / return -1 if device access failure.
429 *****************************************************************************************/
430error_t vfs_inode_load_all_pages( xptr_t inode_xp );
431
432/******************************************************************************************
433 * This debug function display the curren state of an inode descriptor.
434 * It can be called by any thread running in any cluster.
435 *****************************************************************************************/
436void vfs_inode_display( xptr_t inode_xp );
437
438
439
440
441
442
443/******************************************************************************************
444 * This structure defines a directory entry.
445 * A dentry contains the name of a remote file/dir, an extended pointer on the
446 * inode representing this file/dir, a local pointer on the inode representing
447 * the parent directory.
448 * A dentry can be member of the set of children of a given directory inode (xhtab).
449 * A dentry can be member of the set of parents  of a given inode (xlist).
450 *****************************************************************************************/
451
452typedef struct vfs_dentry_s
453{
454    struct vfs_ctx_s   * ctx;            /*! local pointer on FS context                 */
455        char                 name[CONFIG_VFS_MAX_NAME_LENGTH];
456        uint32_t             length;         /*! name length (bytes)                         */
457    struct vfs_inode_s * parent;         /*! local pointer on parent inode               */
458    xptr_t               child_xp;       /*! extended pointer on child inode             */
459    xlist_entry_t        children;       /*! member of set of children dentries          */
460    xlist_entry_t        parents;        /*! member of set of parent dentries            */
461        void               * extend;         /*! FS specific extension                       */
462}
463vfs_dentry_t;
464
465/******************************************************************************************
466 *        These low-level functions access / modify a VFS dentry descriptor
467 *****************************************************************************************/
468
469/******************************************************************************************
470 * This function allocates memory in cluster identified by the <cxy> argument
471 * for a dentry descriptor, initialises it from  arguments values, and returns
472 * in <dentry_xp> the extended pointer on dentry.
473 * It can be called by any thread running in any cluster.
474 ******************************************************************************************
475 * @ cxy        : [in]  target cluster identifier
476 * @ fs_type    : [in]  file system type.
477 * @ name       : [in]  directory entry file/dir name.
478 * @ dentry_xp  : [out] buffer for extended pointer on created dentry.
479 * @ return 0 if success / return ENOMEM or EINVAL if error.
480 *****************************************************************************************/
481error_t vfs_dentry_create( cxy_t           cxy,
482                           vfs_fs_type_t   fs_type,
483                           char          * name,
484                           xptr_t        * dentry_xp );
485 
486/******************************************************************************************
487 * This function removes the dentry from the parent inode xhtab, and releases the memory
488 * allocated to the dentry descriptor.
489 * It can be called by any thread running in any cluster.
490 ******************************************************************************************
491 * @ dentry_xp  : [in] extended pointer on dentry descriptor.
492 *****************************************************************************************/
493void vfs_dentry_destroy( xptr_t  dentry_xp ); 
494
495
496
497
498
499
500
501
502/******************************************************************************************
503 *        These functions access / modify the distributed VFS Inode Tree
504 *****************************************************************************************/
505
506/******************************************************************************************
507 * This function returns in a kernel <buffer> allocated by the caller function,
508 * the pathname of a file/dir identified by the <inode_xp> argument.
509 * It traverse the Inode Tree from the target node to the root.
510 * It can be called by any thread running in any cluster.
511 * As this buffer if filled in "reverse order" (i.e. from the target inode to the root),
512 * the pathname is stored in the higher part of the buffer.
513 * A pointer on the first character of the pathname is returned in <first> buffer.
514 *
515 * WARNING : This function takes & releases the remote_rwlock protecting the Inode Tree.
516 ******************************************************************************************
517 * @ inode_xp    : [in]  extended pointer on target inode descriptor.
518 * @ buffer      : [in]  kernel buffer for pathname (allocated by caller).
519 * @ first       : [out] pointer on first character in buffer.
520 * @ max_size    : [in]  max number of characters in buffer.
521 * @ return 0 if success / return EINVAL if buffer too small.
522 *****************************************************************************************/
523error_t vfs_get_path( xptr_t    inode_xp,
524                      char    * buffer,
525                      char   ** first,
526                      uint32_t  max_size );
527
528/******************************************************************************************
529 * This function traverses the the Inode Tree, from inode identified by the <root_xp>
530 * argument, and returns in <inode_xp> the inode identified by the < pathname> argument.
531 * It can be called by a thread running in any cluster.
532 * It supports the following flags that define the lookup modes :
533 * - VFS_LOOKUP_DIR    : the searched inode must be a directory
534 * - VFS_LOOKUP_OPEN   : the search is for an open/opendir
535 * - VFS_LOOKUP_PARENT : return the parent inode (not the inode itself)
536 * - VFS_LOOKUP_CREATE : file/directory must be created if missing on IOC
537 * - VFS_LOOKUP_EXCL   : file cannot previously exist
538 * As the inode Tree is a cache, the search policy is the following :
539 * - If a given directory name in the path is not found in the inode tree, it try to load
540 *   the missing dentry/inode couple, from informations found in the parent directory.
541 * - If this directory entry does not exist on IOC, it returns an error.
542 * - If the file identified by the pathname does not exist on IOC but the
543 *   flag CREATE is set, the inode is created. It returns an error otherwise.
544 * - If the the file identified by the pathname exist on device, but both flags EXCL
545 *   and CREATE are set, an error is returned.
546 * - If the PARENT flag is set, it returns in <inode_xp> an extended pointer on the parent
547 *   inode, and copies in <last_name> buffer a string containing the last name in path.
548 *
549 * WARNING : The lock protecting the Inode Tree must be taken in read mode by the caller.
550 *
551 * TODO the access rights are not checked yet.
552 ******************************************************************************************
553 * @ root_xp     : [in]  extended pointer on root inode (can be root of a subtree).
554 * @ pathname    : [in]  path (can be relative or absolute).
555 * @ lookup_mode : [in]  flags defining the searching mode.
556 * @ inode_xp    : [out] buffer for extended pointer on searched inode.
557 * @ last_name   : [out] pointer on buffer for last name in path.
558 * @ return 0 if success / ENOENT if inode not found , EACCES if permisson denied,
559 *****************************************************************************************/
560error_t vfs_lookup( xptr_t             root_xp,
561                    char             * pathname,
562                    uint32_t           lookup_mode,
563                                        xptr_t           * inode_xp,
564                    char             * last_name );
565
566/******************************************************************************************
567 * This function creates a new couple dentry/inode, and insert it in the Inode-Tree.
568 * Only the distributed Inode-Tree is modified: it does NOT modify the parent mapper,
569 * and does NOT update the FS on IOC device.
570 * It set the inode type to the default FILE_TYPE_REG value.
571 * It can be executed by any thread running in any cluster (can be different from both
572 * the child cluster and the parent cluster).
573 * The new child inode and the parent inode can have different FS types.
574 *
575 * WARNING : The lock protecting the Inode Tree must be taken in write mode by the caller.
576 ******************************************************************************************
577 * Implementation note
578 * As there are cross-references between inode and dentry, this function implements
579 * a five steps scenario :
580 * 1) The dentry descriptor is created in the cluster containing the existing <parent_xp>
581 *    inode, and partially initialized, using the RPC_VFS_CREATE DENTRY if required.
582 * 2) The inode and its associated mapper are created in cluster identified by <child_cxy>,
583 *    and partially initialised, using the RPC_VFS_CREATE_INODE if required.
584 * 3) The pointers on dentry in parent inode are updated, using remote access.
585 * 4) The pointers on dentry in child inode are updated, using remotes access.
586 * 5) The pointers on parent and child inode in dentry are updated, using remotes access.
587 *****************************************************************************************
588 * @ child_inode_cxy  : [in]  target cluster for child inode.
589 * @ fs_type          : [in]  child inode FS type.
590 * @ parent_inode_xp  : [in]  extended pointer on parent inode.
591 * @ name             : [in]  new directory entry name.
592 * @ dentry_xp        : [out] buffer for extended pointer on dentry
593 * @ child_inode_xp   : [out] buffer for extended pointer on child inode.
594 * @ return 0 if success / -1 if dentry or inode cannot be created.
595 *****************************************************************************************/
596error_t vfs_add_child_in_parent( cxy_t              child_inode_cxy,
597                                 vfs_fs_type_t      fs_type,
598                                 xptr_t             parent_inode_xp,
599                                 char             * name,
600                                 xptr_t           * dentry_xp,   
601                                 xptr_t           * child_inode_xp );
602
603/******************************************************************************************
604 * This function removes a remote dentry and the associated inode from the Inode-Tree.
605 * - It removes the dentry from the parent inode xhtab ("children" field), and from the
606 *   child inode xlist ("parents" field).
607 * - It releases the memory allocated to the dentry descriptor.
608 * - If the number of parents of the child inode is one, it also releases the memory
609 *   allocated to the child inode.
610 * Only the Inode Tree is modified: it does NOT modify the parent mapper,
611 * and does NOT update the FS on IOC device.
612 * It can be executed by any thread running in any cluster (can be different from both
613 * the inode cluster and the dentry cluster).
614 *
615 * WARNING : The lock protecting the Inode Tree must be taken in write mode by the caller.
616 ******************************************************************************************
617 * @ dentry_xp   : extended pointer on removed dentry.
618 *****************************************************************************************/
619void vfs_remove_child_from_parent( xptr_t dentry_xp );
620
621/******************************************************************************************
622 * This function creates in the directory identified by the <child_inode_xp> argument,
623 * the two special dentries <.> and <..>. The parent directory inode is defined
624 * by the <parent_inode_xp> argument. The two dentries are introduced in the Inode Tree.
625 * They are also introduced in the child directory mapper, and the IOC device is updated.
626 * This function is called by all functions creating a brand new directory : vfs_mkdir(),
627 * devfs_global_init(), and devfs_local_init().
628 *
629 * WARNING : The lock protecting the Inode Tree must be taken in write mode by the caller.
630 ******************************************************************************************
631 * @ child_xp    : extended pointer on new directory inode.
632 * @ parent_xp   : extended pointer on parent directory inode.
633 * @ return 0 if success / -1 if failure.
634 *****************************************************************************************/
635error_t vfs_add_special_dentries( xptr_t  child_inode_xp,
636                                  xptr_t  parent_inode_xp );
637
638/******************************************************************************************
639 * This recursive function diplays a complete inode/dentry sub-tree.
640 * Any inode can be selected as the sub-tree root.
641 *
642 * TODO : this function should be protected against a concurrent Inode-Tree change.
643 ******************************************************************************************
644 * @ inode_xp   : extended pointer on sub-tree root inode.
645 *****************************************************************************************/
646void vfs_display( xptr_t   inode_xp );
647
648/******************************************************************************************
649 * This function mount a given file system type for a given process
650 * TODO non implemented [AG].     
651 *****************************************************************************************/
652error_t vfs_mount_fs_root( struct device_s  * device,
653                                       uint32_t           fs_type,
654                                       struct process_s * process );
655
656
657
658
659/******************************************************************************************
660 *        These functions define the VFS "syscalls" API (user commands)
661 *****************************************************************************************/
662
663/******************************************************************************************
664 * This function moves <size> bytes between a remote file mapper, identified by the
665 * <file_xp> argument, and a - possibly distributed - user space <buffer>, taken into
666 * account the offset in <file_xp>. The transfer direction is defined by <to_buffer>.
667 * It is called by the sys_read() and sys_write() functions.
668 * - for a read, it checks the actual file size (registered in the inode descriptor),
669 *   against the (offset + count), and moves only the significant bytes.
670 * - for a write, it updates the the file size in inode descriptor if required.
671 * In case of write to the mapper, the "inode.size" field is updated as required.
672 ******************************************************************************************
673 * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false.
674 * @ file_xp   : extended pointer on the remote file descriptor.
675 * @ buffer    : user space pointer on buffer (can be physically distributed).
676 * @ count     : requested number of bytes from offset.
677 * @ returns number of bytes actually moved if success / -1 if error.
678 *****************************************************************************************/
679uint32_t vfs_user_move( bool_t   to_buffer,
680                        xptr_t   file_xp, 
681                        void   * buffer,
682                        uint32_t count );
683
684/******************************************************************************************
685 * This function moves <size> bytes between a remote file mapper, identified by the
686 * <file_xp> argument, and a - possibly remote - kernel <buffer_xp>, taken into
687 * account the offset in <file_xp>. The transfer direction is defined by <to_buffer>.
688 * It is called by the elf_load_process() function.
689 ******************************************************************************************
690 * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false.
691 * @ file_xp   : extended pointer on the remote file descriptor.
692 * @ buffer_xp : user space pointer on buffer (can be physically distributed).
693 * @ size      : requested number of bytes from offset.
694 * @ returns 0 if success / -1 if error.
695 *****************************************************************************************/
696error_t vfs_kernel_move( bool_t   to_buffer,
697                         xptr_t   file_xp, 
698                         xptr_t   buffer_xp,
699                         uint32_t size );
700
701/******************************************************************************************
702 * This function allocates a vfs_file_t structure in the cluster containing the inode
703 * identified by the <root_xp> & <path> arguments.
704 * It initializes it, register it in the reference process fd_array identified by the
705 * <process_xp> argument, and returns both the extended pointer on the file descriptor,
706 * and the allocated index in the <file_xp> and <file_id> buffers.
707 * The pathname can be relative to current directory or absolute.
708 * If the inode does not exist in the inode cache, it try to find the file on the IOC
709 * device, and creates an inode on a pseudo randomly selected cluster if found.
710 * It the requested file does not exist on device, it creates a new inode if the
711 * O_CREAT flag is set, and return an error otherwise.
712 *
713 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
714 ******************************************************************************************
715 * @ root_xp     : extended pointer on path root inode.
716 * @ path        : file pathname (absolute or relative to current directory).
717 * @ process_xp  : extended pointer on client reference process.
718 * @ flags       : defined in vfs_file_t structure.
719 * @ mode        : access rights (as defined by chmod).
720 * @ file_xp     : [out] buffer for extended pointer on created remote file descriptor.
721 * @ file_id     : [out] buffer for created file descriptor index in reference fd_array.
722 * @ return 0 if success / return non-zero if error.
723 *****************************************************************************************/
724error_t vfs_open( xptr_t             root_xp,
725                          char             * path,
726                  xptr_t             process_xp,
727                          uint32_t           flags,
728                  uint32_t           mode,
729                          xptr_t           * file_xp,
730                          uint32_t         * file_id );
731
732/******************************************************************************************
733 * This function set a new value in the offset of the open file descriptor <file_xp>.
734 * This value depends on the <whence> argument:
735 * - if VFS_SEEK_SET, new value is <offset>
736 * - if VFS_SEEK_CUR, new value is current_offset + <offset>
737 * - if VFS_SEEK_END, new value is file_size + <offset>
738 ******************************************************************************************
739 * @ file_xp   : extended pointer on the remote open file descriptor.
740 * @ offset    : local pointer on source kernel buffer.
741 * @ whence    : VFS_SEEK_SET / VFS_SEEK_CUR / VFS_SEEK_END.
742 * @ new_offset : [out] buffer for new offset value.
743 * @ returns 0 if success / -1 if error.
744 *****************************************************************************************/
745error_t vfs_lseek( xptr_t     file_xp,
746                   uint32_t   offset,
747                   uint32_t   whence, 
748                   uint32_t * new_offset );
749
750/******************************************************************************************
751 * This function close the - non-replicated - file descriptor identified by the <file_xp>
752 * and <file_id> arguments. The <file_id> is required to reset the fd_array[] slot.
753 * It can be called by a thread running in any cluster, and executes the following actions:
754 * 1) It access the block device to updates all dirty pages from the mapper associated
755 *    to the file, and removes these pages from the dirty list, using an RPC if required.
756 * 2) It updates the file size in all parent directory mapper(s), and update the modified
757 *    pages on the block device, using RPCs if required, only if the size is modified.
758 * 3) All entries in the fd_array copies are directly reset by the calling thread,
759 *    using remote accesses.
760 * 4) The memory allocated to file descriptor in cluster containing the inode is released,
761 *    using an RPC if cluster containing the file descriptor is remote.
762 ******************************************************************************************
763 * @ file_xp     : extended pointer on the file descriptor.
764 * @ file_id     : file descriptor index in fd_array[].
765 * @ returns 0 if success / -1 if error.
766 *****************************************************************************************/
767error_t vfs_close( xptr_t    file_xp,
768                   uint32_t  file_id );
769
770/******************************************************************************************
771 * This function is called by the kernel to create in the file system a new directory
772 * identified by the <root_xp> & <path> arguments, with the access permission defined
773 * by the <rights> argument. All nodes in the path - but the last -  must exist.
774 *
775 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
776 ******************************************************************************************
777 * @ root_xp : extended pointer on path root inode (any inode in Inode Tree).
778 * @ path    : pathname (absolute or relative to current directory).
779 * @ rights  : access rights.
780 * @ returns 0 if success / -1 if error.
781 *****************************************************************************************/
782error_t vfs_mkdir( xptr_t   root_xp,
783                   char   * path,
784                   uint32_t rights );
785
786/******************************************************************************************
787 * This function is called by the kernel to create in the file system a new directory
788 * entry identified by the <new_root_xp> & <new_path> arguments, to be linked to an
789 * existing inode, identified by the  <old_root_xp> & <old_path> arguments.
790 * If the link is successful, the link count of the target inode is incremented.
791 * The <new_path> and <old_path> share equal access rights to the underlying inode.
792 * Both the IOC device and the Inode Tree are modified.
793 $
794 * TODO This function should handle any type of node, but the current implementation
795 * handles only the FILE and DIR types.
796 *
797 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
798 ******************************************************************************************
799 * @ old_root_xp : extended pointer on old path root inode (any inode in Inode Tree).
800 * @ old_path    : old pathname (absolute or relative to current directory).
801 * @ nld_root_xp : extended pointer on new path root inode (any inode in Inode Tree).
802 * @ new_path    : new pathname (absolute or relative to current directory).
803 * @ returns 0 if success / -1 if error.
804 *****************************************************************************************/
805error_t vfs_link( xptr_t   old_root_xp,
806                  char   * old_path,
807                  xptr_t   new_root_xp,
808                  char   * new_path );
809
810/******************************************************************************************
811 * This function is called by the kernel to remove from the file system a directory entry
812 * identified by the  <root_xp> & <path> arguments.
813 * The link count of the target node is decremented.
814 * If the removed link is the last, the target inode is deleted.
815 * Both the IOC device and the Inode Tree are modified.
816 *
817 * TODO This function should handle any type of node, but the current implementation
818 * handles only only the FILE and DIR types.
819 *
820 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
821 ******************************************************************************************
822 * @ root_xp  : extended pointer on root inode (can be any inode in Inode Tree).
823 * @ path     : pathname (absolute or relative to current directory).
824 * @ returns 0 if success / -1 if error.
825 *****************************************************************************************/
826error_t vfs_unlink( xptr_t   root_xp,
827                    char   * path );
828
829/******************************************************************************************
830 * This function returns, in the structure pointed by the <st> pointer, various
831 * informations on the inode identified by the <root_inode_xp> and <patname> arguments.
832 *
833 * TODO : only partially implemented yet (only size and inum fields).
834 *
835 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
836 ******************************************************************************************
837 * @ root_xp    : extended pointer on path root inode (any inode in Inode Tree)
838 * @ pathname   : pathname to target inode.
839 * @ st         : local pointer on the stat structure in kernel space.
840 * @ returns 0 if success / -1 if error.
841 *****************************************************************************************/
842error_t vfs_stat( xptr_t        root_xp,
843                  char        * pathname,
844                  struct stat * st );
845
846/******************************************************************************************
847 * This function  creates a new inode/dentry couple for a new directory, and registers it
848 * in the Inode Tree, as defined by the <root_xp>,  <path>, and <mode> arguments.
849 ******************************************************************************************
850 * @ root_xp  : extended pointer on the path root directory.
851 * @ path     : pathname (absolute or relative to CWD).                     
852 * @ mode     : access rights (as defined by chmod)
853 * @ returns 0 if success / -1 if error.
854 *****************************************************************************************/
855error_t vfs_mkdir( xptr_t     root_xp,
856                   char     * path,
857                   uint32_t   mode );
858
859/******************************************************************************************
860 * This function makes the directory identified by the <root_xp and <path> arguments
861 * to become the working directory for the calling process.
862 ******************************************************************************************
863 * @ root_xp  : extended pointer on the path root directory.
864 * @ path     : pathname (absolute or relative to CWD).
865 * return 0 if success / -1 if error.
866 *****************************************************************************************/
867error_t vfs_chdir( xptr_t   root_xp,
868                   char   * path );
869
870/******************************************************************************************
871 * This function change the access rigths for the file/directory identified by the
872 * <root_xp> and <path> arguments as defined by the <mode> argument value.
873 * TODO not implemented yet
874 ******************************************************************************************
875 * @ root_xp  : extended pointer on the path root directory.
876 * @ path     : pathname (absolute or relative to CWD).
877 * @ mode     : access rights
878 * return 0 if success / -1 if error.
879 *****************************************************************************************/
880error_t vfs_chmod( xptr_t        root_xp,
881                   char        * path,
882                   uint32_t      mode );
883
884/******************************************************************************************
885 * This function creates a new inode/dentry couple of FIFO type, and registers it
886 * in the Inode Tree as specified by the <root_xp>, <path>, and <mode> arguments.
887 ******************************************************************************************
888 * @ root_xp  : [in] extended pointer on the root directory in path.
889 * @ path     : [in] pathname (absolute or relative to CWD).
890 * @ mode     : [in] access rights new value.
891 *****************************************************************************************/
892error_t vfs_mkfifo( xptr_t       root_xp,
893                    char       * path,
894                    uint32_t     mode );
895
896
897
898
899
900/******************************************************************************************
901 *      These functions define the VFS "FS" API to access a specific File System
902 *****************************************************************************************/
903
904/******************************************************************************************
905 * This function introduces in a directory mapper identified by the <parent_inode_xp>
906 * argument, a new entry identified by the <dentry_ptr> argument.
907 * Depending on the file system type, it calls the proper, FS specific function.
908 * All informations related to the new directory must be contained in the dentry
909 * descriptor, or in the associated child inode descriptor.
910 * The dentry descriptor "extend" field is updated as required by the specific FS.
911 * Finally, it synchronously updates the parent directory on IOC device.
912 * This function can be called by any thread running in any cluster.
913 ******************************************************************************************
914 * @ parent  : local pointer on parent (directory) inode.
915 * @ dentry  : local pointer on dentry containing name.
916 * @ return 0 if success / return -1 if device access failure.
917 *****************************************************************************************/
918error_t vfs_fs_add_dentry( xptr_t         parent_inode_xp,
919                           vfs_dentry_t * dentry_ptr );
920
921/******************************************************************************************
922 * This function removes from a directory mapper identified by the <parent_inode_xp>
923 * argument, an entry identified by the <dentry_ptr> argument.
924 * Depending on the file system type, it calls the proper, FS specific function.
925 * Finally, it synchronously updates the parent directory on IOC device.
926 * This function can be called by any thread running in any cluster.
927 ******************************************************************************************
928 * @ parent_inode_xp  : extended pointer on parent (directory) inode.
929 * @ dentry_ptr       : local pointer on dentry containing name.
930 * @ return 0 if success / return -1 if device access failure.
931 *****************************************************************************************/
932error_t vfs_fs_remove_dentry( xptr_t         parent_inode_xp,
933                              vfs_dentry_t * dentry_ptr );
934
935/******************************************************************************************
936 * This function scan a directory mapper, identified by the <parent_inode_xp> argument
937 * to find a directory entry identified by the <dentry_ptr> argument,
938 * and updates both the child inode descriptor, and the associated dentry descriptor:
939 * - It set the "size", "type", and "extend" fields in inode descriptor.
940 * - It set the "extend" field in dentry descriptor.
941 * It is called by the vfs_lookup() function in case of miss, and does NOT take any lock.
942 * Depending on the file system type, it calls the relevant, FS specific function.
943 * This function can be called by any thread running in any cluster.
944 ******************************************************************************************
945 * @ parent_inode_xp  : extended pointer on parent inode (directory).
946 * @ dentry_ptr       : local pointer on new entry (in parent inode cluster).
947 * @ return 0 if success / return -1 if dentry not found.
948 *****************************************************************************************/
949error_t vfs_fs_new_dentry_from_mapper( xptr_t         parent_inode_xp,
950                                       vfs_dentry_t * dentry_ptr );
951
952/*****************************************************************************************
953 * This function  introduces a brand new dentry identified by the <dentry_ptr> argument
954 * in the mapper of a directory identified by the <parent_inode_xp> argument.
955 * It is called by the vfs_lookup() function, and does NOT take any lock.
956 * The child inode descriptor, and the dentry descriptor must have been previously
957 * allocated and introduced in the Inode Tree. The dentry descriptor contains the name.
958 * Depending on the file system type, it calls the relevant, FS specific function.
959 * This function can be called by any thread running in any cluster.
960 *****************************************************************************************
961 * @ parent_inode_xp : [in]  extended pointer on parent inode (directory).
962 * @ dentry_ptr      : [in]  local pointer on dentry (in parent inode cluster).
963 * @ return 0 if success / return -1 if failure.
964 ****************************************************************************************/
965error_t vfs_fs_new_dentry_to_mapper( xptr_t         parent_inode_xp,
966                                     vfs_dentry_t * dentry_ptr );
967
968/******************************************************************************************
969 * This function updates the "size" field of a directory entry identified by the
970 * <dentry_ptr> argument in a directory mapper identified by the <parent_inode_xp>
971 * from the value contained in the inode descriptor.
972 * The parent directory on device is synchronously updated.
973 * It is called by the vfs_close() function.
974 * Depending on the file system type, it calls the relevant, FS specific function.
975 * This function can be called by any thread running in any cluster.
976 ******************************************************************************************
977 * @ parent_inode_xp  : local pointer on parent inode (directory).
978 * @ dentry_ptr       : local pointer on dentry (in parent directory cluster).
979 * @ return 0 if success / return -1 if not found.
980 *****************************************************************************************/
981error_t vfs_fs_update_dentry( xptr_t         parent_inode_xp,
982                              vfs_dentry_t * dentry_ptr );
983
984/******************************************************************************************
985 * This function scan the mapper of an an existing parent inode directory, identified by
986 * the <inode> argument and copy up to <max_dirent> valid dentries to a
987 * local dirent array, defined by the <array> argument. The <min_dentry> argument defines
988 * the index of the first dentry to copied to the target dirent array.
989 * This function returns in the <entries> buffer the number of dentries actually written,
990 * and signals in the <done> buffer when the last valid entry has been found.
991 * If the <detailed> argument is true, a dentry/inode couple that does not exist in
992 * the Inode Tree is dynamically created, and all dirent fiels are documented in the
993 * dirent array. Otherwise, only the dentry name is documented.
994 * This function does NOT take any lock.
995 * Depending on the file system type, it calls the relevant, FS specific function.
996 *
997 * WARNING : this function must be called by a thread running in the cluster containing
998 * the target directory inode.
999 ******************************************************************************************
1000 * @ inode      : [in]  local pointer on directory inode.
1001 * @ array      : [in]  local pointer on array of dirents.
1002 * @ max_dirent : [in]  max number of slots in dirent array.
1003 * @ min_dentry : [in]  index of first dentry to be copied into array.
1004 * @ detailed   : [in]  dynamic inode creation if true.
1005 * @ entries    : [out] number of dentries actually copied into array.
1006 * @ done       : [out] Boolean true when last entry found.
1007 * @ return 0 if success / return -1 if failure.
1008 *****************************************************************************************/
1009error_t vfs_fs_get_user_dir( vfs_inode_t   * inode,
1010                             struct dirent * array,
1011                             uint32_t        max_dirent,
1012                             uint32_t        min_dentry,
1013                             bool_t          detailed,
1014                             uint32_t      * entries,
1015                             bool_t        * done );
1016 
1017/*****************************************************************************************
1018 * This function  updates the FS on the IOC device for a given inode identified by
1019 * the <inode> argument. It scan all pages registered in the associated mapper,
1020 * and copies from mapper to device each page marked as dirty.
1021 * WARNING : The target <inode> cannot be a directory, because all modifications in a
1022 * directory are synchronously done on the IOC device by the two vfs_fs_add_dentry()
1023 * and vfs_fs_remove_dentry() functions.
1024 * Depending on the file system type, it calls the relevant, FS specific function.
1025 * This function can be called by any thread running in any cluster.
1026 *****************************************************************************************
1027 * @ inode_xp   : remote pointer on inode.
1028 * @ return 0 if success / return -1 if failure.
1029 ****************************************************************************************/
1030error_t vfs_fs_sync_inode( xptr_t inode_xp );
1031
1032/*****************************************************************************************
1033 * This function updates the FS defined by the <fs_type> argument on the IOC device
1034 * for the FAT itself. It scan all clusters registered in the FAT mapper, and copies
1035 * to device each page marked as dirty.
1036 * Depending on the file system type, it calls the relevant, FS specific function.
1037 * It can be called by a thread running in any cluster.
1038 *****************************************************************************************
1039 * @ fs_type   : specific file system type.
1040 * @ return 0 if success / return EIO if failure during device access.
1041 ****************************************************************************************/
1042error_t vfs_fs_sync_fat( vfs_fs_type_t fs_type );
1043
1044/******************************************************************************************
1045 * This function makes all I/O operations required to release all clusters allocated
1046 * on IOC device to a given inode, identified by the <inode_xp> argument.
1047 * Depending on the file system type, it calls the proper, FS specific function.
1048 * It is called by the vfs_unlink() function.
1049 * This function does NOT take any lock.
1050 * Depending on the file system type, it calls the relevant, FS specific function.
1051 * This function can be executed by any thread running in any cluster.
1052 ******************************************************************************************
1053 * @ inode_xp  : extended pointer on inode.
1054 * @ return 0 if success / return -1 if device access failure.
1055 *****************************************************************************************/
1056error_t vfs_fs_release_inode( xptr_t  inode_xp ); 
1057
1058/******************************************************************************************
1059 * This function makes the I/O operation to move one page identified by the <page_xp>
1060 * argument to/from the IOC device from/to the mapper, as defined by the <cmd_type>.
1061 * It is used in case of MISS on the mapper (read), or when a dirty page in the mapper
1062 * must be updated in the File System (write).
1063 * The mapper pointer, and the page index in file are obtained from the page descriptor.
1064 * This function does NOT take any lock.
1065 * Depending on the file system type, it calls the proper, FS specific function.
1066 * This function can be executed by any thread running in any cluster.
1067 ******************************************************************************************
1068 * @ page_xp   : extended pointer on page descriptor (for mapper and page_id).
1069 * @ cmd_type  : IOC_READ / IOC_WRITE / IOC_SYNC_READ / IOC_SYNC_WRITE
1070 * @ returns 0 if success / return -1 if device access failure.
1071 *****************************************************************************************/
1072error_t vfs_fs_move_page( xptr_t          page_xp,
1073                          ioc_cmd_type_t  cmd_type );
1074
1075
1076#endif  /* _VFS_H_ */
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