source: trunk/kernel/fs/vfs.h @ 561

Last change on this file since 561 was 561, checked in by nicolas.van.phan@…, 3 years ago

Remove y_max in all functions except dqdt_init()

File size: 45.9 KB
Line 
1/*
2 * vfs.h - Virtual File System 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 _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_spinlock.h>
33#include <spinlock.h>
34#include <list.h>
35#include <xlist.h>
36#include <slist.h>
37#include <bits.h>
38#include <xhtab.h>
39#include <errno.h>
40#include <shared_syscalls.h>
41#include <fatfs.h>
42#include <ramfs.h>
43#include <devfs.h>
44
45/****  Forward declarations  ***/
46
47struct vfs_inode_s;
48struct vfs_dentry_t;
49struct vfs_ctx_t;
50struct vfs_file_ref_s;
51struct vfs_file_s;
52
53struct vfs_inode_op_s;
54struct vfs_dentry_op_s;
55struct vfs_file_op_s;
56struct vfs_ctx_op_s;
57
58struct vfs_lookup_cmd_s;
59struct vfs_lookup_rsp_s;
60
61struct mapper_s;
62struct process_s;
63struct device_s;
64struct vseg_s;
65struct page_s;
66
67
68/******************************************************************************************
69 * These flags are used to define the working mode of the vfs_lookup() function. 
70 *****************************************************************************************/
71
72#define VFS_LOOKUP_DIR      0x01     /* the searched inode is a directory                */
73#define VFS_LOOKUP_OPEN         0x02     /* the search is for an open/opendir                */
74#define VFS_LOOKUP_PARENT       0x04     /* return the parent inode (not the inode itself)   */
75#define VFS_LOOKUP_CREATE   0x10     /* file must be created if missing                  */
76#define VFS_LOOKUP_EXCL     0x20     /* file cannot previously exist                     */   
77
78/******************************************************************************************
79 * This define the masks for the POSIX access rights to inodes
80 *****************************************************************************************/
81
82#define VFS_ISUID                0x0004000
83#define VFS_ISGID                0x0002000
84#define VFS_ISVTX                0x0001000
85
86#define VFS_IRWXU            0x0000700
87#define VFS_IRUSR            0x0000400
88#define VFS_IWUSR            0x0000200
89#define VFS_IXUSR            0x0000100
90
91#define VFS_IRWXG            0x0000070
92#define VFS_IRGRP            0x0000040
93#define VFS_IWGRP            0x0000020
94#define VFS_IXGRP            0x0000010
95
96#define VFS_IRWXO            0x0000007
97#define VFS_IROTH            0x0000004
98#define VFS_IWOTH            0x0000002
99#define VFS_IXOTH            0x0000001
100
101#define VFS_IREAD            VFS_IRUSR
102#define VFS_IWRITE           VFS_IWUSR
103#define VFS_IEXEC            VFS_IXUSR
104
105
106/******************************************************************************************
107 * This structure defines informations common to all inodes and dentries
108 * of a given file system. As it is declared a global variable in the kdata segment,
109 * it is replicated in all clusters and handled as private by each OS intance.
110 *****************************************************************************************/
111
112typedef enum
113{
114        FS_TYPE_DEVFS = 0,
115        FS_TYPE_FATFS = 1,
116        FS_TYPE_RAMFS = 2,
117 
118        FS_TYPES_NR   = 3,
119}
120vfs_fs_type_t;
121
122typedef enum
123{
124    CTX_ATTR_READ_ONLY    = 0x01,            /*! write access prohibited                 */
125    CTX_ATTR_SYNC         = 0x10,            /*! synchronise FS on each write            */
126}
127vfs_ctx_attr_t;
128
129typedef struct vfs_ctx_s
130{
131        vfs_fs_type_t  type;                     /*! File System type                        */
132        uint32_t           attr;                     /*! global attributes for all files in FS   */
133        uint32_t       total_clusters;           /*! total number of clusters on device      */
134        uint32_t       cluster_size;             /*! cluster size on device (bytes)          */
135        xptr_t         vfs_root_xp;              /*! extended pointer on VFS root inode      */
136    spinlock_t     lock;                     /*! lock protecting inum allocator          */
137    uint32_t       bitmap[BITMAP_SIZE(CONFIG_VFS_MAX_INODES)];  /* inum allocator        */
138    void         * extend;                   /*! FS specific context extension           */
139}
140vfs_ctx_t;
141
142/******************************************************************************************
143 * This structure define a VFS inode.
144 * It contains an extended pointer on the parent dentry, and (for directory only)
145 * an hash table xhtab refering all children dentries.
146 * The <parent> inode is unique for a directory (not hard links for directories).
147 * For a file, the parent field points to the first dentry who created this inode.
148 * Syncrhonisation:
149 * - the main_lock (spinlock) is used during the inode tree traversal or for inode
150 *   modification (add/remove children).
151 * - the data_lock (rwlock) is used during read/write accesses to the data stored
152 *   in the mapper.
153 * - the mapper lock (rwlock) is only used during the radix tree traversal to return
154 *   the relevant page for read/write.
155 *****************************************************************************************/
156
157/* this enum define the VFS inode types values */
158
159typedef enum   
160{
161    INODE_TYPE_FILE  =     0,           /*! file                                         */
162    INODE_TYPE_DIR   =     1,           /*! directory                                    */
163    INODE_TYPE_FIFO  =     2,           /*! POSIX named pipe                             */
164    INODE_TYPE_PIPE  =     3,           /*! POSIX anonymous pipe                         */
165    INODE_TYPE_SOCK  =     4,           /*! POSIX socket                                 */
166    INODE_TYPE_DEV   =     5,           /*! device channel                               */
167    INODE_TYPE_SYML  =     6,           /*! symbolic link                                */
168}
169vfs_inode_type_t;
170
171/* this enum define the VFS inode attributes values */
172
173typedef enum 
174{
175    INODE_ATTR_DIRTY   =     0x01,       /* modified versus the value on device          */ 
176    INODE_ATTR_INLOAD  =     0x04,       /* loading from device in progress              */
177    INODE_ATTR_NEW     =     0x08,       /* not saved on device yet                      */
178}
179vfs_inode_attr_t;
180
181typedef struct vfs_inode_s
182{
183        struct vfs_ctx_s * ctx;              /*! local pointer on FS context                 */
184    uint32_t           gc;               /*! generation counter                          */
185        uint32_t           inum;             /*! inode identifier (unique in file system)    */
186        uint32_t           attr;             /*! inode attributes (see above)                */
187        vfs_inode_type_t   type;             /*! inode type (see above)                      */
188        uint32_t           size;             /*! number of bytes                             */
189        uint32_t           links;            /*! number of alias dentry                      */
190        uid_t              uid;              /*! user owner identifier                       */
191        gid_t              gid;              /*! group owner identifier                      */
192    uint32_t           rights;           /*! access rights                               */
193        uint32_t               refcount;         /*! reference counter (all pointers)            */
194        xptr_t             parent_xp;        /*! extended pointer on parent dentry           */
195        xhtab_t            children;         /*! embedded xhtab of children dentries         */
196        remote_rwlock_t    data_lock;        /*! protect read/write to data and to size      */
197        remote_spinlock_t  main_lock;        /*! protect inode tree traversal and modifs     */
198        list_entry_t       list;             /*! member of set of inodes in same cluster     */
199        xlist_entry_t      wait_root;        /*! root of threads waiting on this inode       */
200        struct mapper_s  * mapper;           /*! associated file cache                       */
201        void             * extend;           /*! fs_type_specific inode extension            */
202}
203vfs_inode_t;
204
205/******************************************************************************************
206 * This structure defines a directory entry.
207 * A dentry contains the name of a remote file/dir, an extended pointer on the
208 * inode representing this file/dir, and a local pointer on the inode representing
209 * the parent directory.
210 *****************************************************************************************/
211
212typedef struct vfs_dentry_s
213{
214    struct vfs_ctx_s   * ctx;            /*! local pointer on FS context                 */
215        char                 name[CONFIG_VFS_MAX_NAME_LENGTH];
216        uint32_t             length;         /*! name length (bytes)                         */
217        uint32_t             refcount;       /*! reference counter (all pointers)            */
218    struct vfs_inode_s * parent;         /*! local pointer on parent inode               */
219    xptr_t               child_xp;       /*! extended pointer on child inode             */
220    xlist_entry_t        list;           /*! member of list of dentries with same key    */
221        void               * extend;         /*! FS specific extension                       */
222}
223vfs_dentry_t;
224
225/******************************************************************************************
226 * This file structure describes an open file/directory for a given process.
227 * It is not replicated, and is dynamically allocated in the cluster that contains
228 * the inode, when a thread makes an open() or opendir() system call.
229 * It cannot exist a file structure without an inode structure in same cluster.
230 * As the fd_array (containing extended pointers on the open file descriptors)
231 * is replicated in all process descriptors, we need a references counter.
232 *****************************************************************************************/
233
234typedef enum
235{
236    FD_ATTR_READ_ENABLE    = 0x01,     /*! read access possible                         */
237    FD_ATTR_WRITE_ENABLE   = 0x02,     /*! write access possible                        */
238    FD_ATTR_APPEND         = 0x04,     /*! append on each write                         */
239    FD_ATTR_CLOSE_EXEC     = 0x08,     /*! close file on exec                           */
240    FD_ATTR_SYNC           = 0x10,     /*! synchronise FS on each write                 */
241    FD_ATTR_IS_DIR         = 0x20,     /*! this is a directory                          */
242}
243vfs_file_attr_t;
244
245typedef struct vfs_file_s
246{
247        struct vfs_ctx_s      * ctx;        /*! local pointer on FS context.                 */
248        uint32_t                gc;         /*! generation counter                           */
249        vfs_file_attr_t         attr;       /*! file attributes bit vector (see above)       */
250        vfs_inode_type_t        type;       /*! same type as inode                           */
251        uint32_t                offset;     /*! seek position in file                        */
252        uint32_t                refcount;   /*! all pointers on this file descriptor         */
253        remote_rwlock_t         lock;       /*! protect offset modifications                 */
254        struct mapper_s       * mapper;     /*! associated file cache                        */
255        struct vfs_inode_s    * inode;      /*! local pointer on associated inode            */
256        void                  * extend;     /*! FS specific extension                        */
257}
258vfs_file_t;
259
260
261/*****************************************************************************************/
262/******************** VFS global functions ***********************************************/
263/*****************************************************************************************/ 
264
265
266/******************************************************************************************
267 * This function mount a given file system type for a given process TODO.     
268 *****************************************************************************************/
269error_t vfs_mount_fs_root( struct device_s  * device,
270                                       uint32_t           fs_type,
271                                       struct process_s * process );
272
273
274/*****************************************************************************************/
275/******************* VFS Context related functions ****************************************/
276/*****************************************************************************************/
277
278/******************************************************************************************
279 * This function initialise a (statically allocated) VFS context in local cluster.
280 ******************************************************************************************
281 * @ fs_type        : file system type.
282 * @ attr           : global attributes (for all files in FS.
283 * @ total_clusters : total number of clusters on device.
284 * @ cluster_size   : cluster size on device (bytes).
285 * @ vfs_root_xp    : extended pointer on VFS root inode.
286 * @ extend         : fs_type_specific extension.
287 *****************************************************************************************/
288void vfs_ctx_init( vfs_fs_type_t   type,
289                   uint32_t        attr,
290                       uint32_t        total_clusters,
291                       uint32_t        cluster_size,
292                       xptr_t          vfs_root_xp,
293                   void          * extend );
294
295/******************************************************************************************
296 * This function allocates an inode identifier from the local cluster inum allocator.
297 * The inum respects a fixed format:
298 * - the 16 MSB bits contain the cluster identifier : cxy
299 * - the 16 LSB bits contains the local inode identifier  : lid
300 ******************************************************************************************
301 * @ ctx      : local pointer on file system context.
302 * @ inum     : [ou] buffer for allocated inode identifier.
303 * @ return 0 if success / return non-zero if error.
304 *****************************************************************************************/
305error_t vfs_ctx_inum_alloc( vfs_ctx_t * ctx,
306                            uint32_t  * inum );
307
308/******************************************************************************************
309 * This function release an inode identifier.                                 
310 ******************************************************************************************
311 * @ ctx      : local pointer on file system context.
312 * @ inum     : released inode identifier.
313 *****************************************************************************************/
314void vfs_ctx_inum_release( vfs_ctx_t * ctx,
315                           uint32_t    inum );
316
317
318
319
320/*****************************************************************************************/
321/********************* Inode related functions *******************************************/
322/*****************************************************************************************/
323
324/******************************************************************************************
325 * This function allocates memory from local cluster for an inode descriptor and the
326 * associated mapper. It initialise these descriptors from arguments values.
327 * The parent dentry must have been previously created.
328 * If the client thread is not running in the cluster containing this inode,
329 * it must use the rpc_vfs_inode_create_client() function.
330 ******************************************************************************************
331 * @ dentry_xp  : extended pointer on associated dentry (in parent inode cluster).
332 * @ fs_type    : file system type.
333 * @ inode_type : inode type.
334 * @ extend     : local pointer on vs_type_specific extension.
335 * @ attr       : inode attributes.
336 * @ rights     : inode access rights.
337 * @ uid        : user owner ID.
338 * @ gid        : group owner ID.
339 * @ inode_xp   : [out] buffer for extended pointer on created inode.
340 * @ return 0 if success / return ENOMEM or EINVAL if error.
341 *****************************************************************************************/
342error_t vfs_inode_create( xptr_t            dentry_xp,
343                          vfs_fs_type_t     fs_type,
344                          vfs_inode_type_t  inode_type,
345                          void            * extend,
346                          uint32_t          attr,
347                          uint32_t          rights,
348                          uid_t             uid,
349                          gid_t             gid,
350                          xptr_t          * inode_xp );
351
352/******************************************************************************************
353 * This function releases memory allocated to an inode descriptor.
354 * It must be executed by a thread running in the cluster containing the inode,
355 * and the inode refcount must be zero. If the client thread is not running in the owner
356 * cluster, you must use the rpc_vfs_inode_destroy_client() function.
357 ******************************************************************************************
358 * @ inode  : local pointer on inode descriptor.
359 * @ return 0 if success / return EINVAL if error.
360 *****************************************************************************************/
361error_t vfs_inode_destroy( vfs_inode_t *  inode ); 
362
363/******************************************************************************************
364 * This function scan an existing parent inode directory, identified by the <parent>
365 * argument to find a directory entry identified by the <name> argument, and update
366 * the remote child inode, identified by the <child_xp> argument.
367 * Depending on the file system type, it calls the relevant, FS specific function,
368 * to scan the directory, and set the "type", "size", and "extend" fields.
369 * It must be called by a thread running in the cluster containing the parent inode.
370 ******************************************************************************************
371 * @ parent    : local pointer on parent inode (directory).
372 * @ name      : child name.
373 * @ child_xp  : extended pointer on remote child inode (file or directory)
374 * @ return 0 if success / return ENOENT if not found.
375 *****************************************************************************************/
376error_t vfs_inode_load( vfs_inode_t * parent,
377                        char        * name,
378                        xptr_t        child_xp );
379
380/******************************************************************************************
381 * This function atomically increment/decrement the inode refcount.
382 * It can be called by any thread running in any cluster.
383 *****************************************************************************************/
384void vfs_inode_remote_up( xptr_t  inode_xp );
385void vfs_inode_remote_down( xptr_t  inode_xp );
386
387/******************************************************************************************
388 * This function returns the <size> of a file/dir from a remote inode,
389 * taking the remote_rwlock protecting <size> in READ_MODE.
390 *****************************************************************************************
391 * @ inode_xp  : extended pointer on the remote inode.
392 * @ return the current size.
393 *****************************************************************************************/
394uint32_t vfs_inode_get_size( xptr_t inode_xp );
395
396/******************************************************************************************
397 * This function set the <size> of a file/dir to a remote inode,
398 * taking the remote_rwlock protecting <size> in WRITE_MODE.
399 *****************************************************************************************
400 * @ inode_xp  : extended pointer on the remote inode.
401 * @ size      : value to be written.
402 *****************************************************************************************/
403void vfs_inode_set_size( xptr_t   inode_xp,
404                         uint32_t size );
405
406/******************************************************************************************
407 * This function takes the main lock of a remote inode.
408 * This lock protect all inode fiels, including the children dentries.
409 *****************************************************************************************
410 * @ inode_xp  : extended pointer on the remote inode.
411 *****************************************************************************************/
412void vfs_inode_lock( xptr_t inode_xp );
413
414/******************************************************************************************
415 * This function releases the main lock of a remote inode.
416 * This lock protect all inode fiels, including the children dentries.
417 *****************************************************************************************
418 * @ inode_xp  : extended pointer on the remote inode.
419 *****************************************************************************************/
420void vfs_inode_unlock( xptr_t inode_xp );
421
422/******************************************************************************************
423 * This debug function copies the name of a remote inode identified by the <inode_xp>
424 * argument to a local buffer identified by the <name> argument.
425 * The local buffer size must be at least CONFIG_VFS_MAX_NAME_LENGTH.
426 *****************************************************************************************
427 * @ inode_xp  : extended pointer on the remote inode.
428 * @ name      : local buffer pointer.
429 *****************************************************************************************/
430void vfs_inode_get_name( xptr_t inode_xp,
431                         char * name );
432
433
434/*****************************************************************************************/
435/***************** Dentry related functions **********************************************/
436/*****************************************************************************************/
437
438/******************************************************************************************
439 * This function allocates memory from local cluster for a dentry descriptor,
440 * initialises it from  arguments values, and returns the extended pointer on dentry.
441 * The inode field is not initialized, because the inode does not exist yet.
442 * If the client thread is not running in the target cluster for this inode,
443 * it must use the rpc_dentry_create_client() function.
444 ******************************************************************************************
445 * @ fs_type    : file system type.
446 * @ name       : directory entry file/dir name.
447 * @ parent     : local pointer on parent inode.
448 * @ dentry_xp  : [out] buffer for extended pointer on created dentry.
449 * @ return 0 if success / return ENOMEM or EINVAL if error.
450 *****************************************************************************************/
451error_t vfs_dentry_create( vfs_fs_type_t   fs_type,
452                           char          * name,
453                           vfs_inode_t   * parent,
454                           xptr_t        * dentry_xp );
455 
456/******************************************************************************************
457 * This function releases memory allocated to a dentry descriptor.
458 * It must be executed by a thread running in the cluster containing the dentry,
459 * and the dentry refcount must be zero. If the client thread is not running in the owner
460 * cluster, you must use the rpc_dentry_destroy_client() function.
461 ******************************************************************************************
462 * @ dentry  : local pointer on dentry descriptor.
463 * @ return 0 if success / return EINVAL if error.
464 *****************************************************************************************/
465error_t vfs_dentry_destroy( vfs_dentry_t *  dentry ); 
466
467/******************************************************************************************
468 * These functions atomically increment/decrement the dentry refcount.
469 * It can be called by any thread running in any cluster.
470 *****************************************************************************************/
471void vfs_dentry_remote_up( xptr_t dentry_xp );
472void vfs_dentry_remote_down( xptr_t dentry_xp );
473
474
475/*****************************************************************************************/
476/************************ File descriptor related functions ******************************/
477/*****************************************************************************************/
478
479/******************************************************************************************
480 * This function allocates memory and initializes a new local file descriptor.
481 * It must be executed in the cluster containing the inode.
482 * If the client thread is not running in the owner cluster, it must use the
483 * rpc_vfs_file_create_client() function.
484 ******************************************************************************************
485 * @ inode    : local pointer on associated inode.
486 * @ attr     : file descriptor attributes.
487 * @ file_xp  : [out] buffer for extended pointer on created file descriptor.
488 * @ return 0 if success / return ENOMEM if error.
489 *****************************************************************************************/
490error_t vfs_file_create( vfs_inode_t * inode,
491                         uint32_t      attr,
492                         xptr_t      * file_xp ); 
493
494/******************************************************************************************
495 * This function releases memory allocated to a local file descriptor.
496 * It must be executed by a thread running in the cluster containing the inode,
497 * and the file refcount must be zero.
498 * If the client thread is not running in the owner cluster, it must use the
499 * rpc_vfs_file_destroy_client() function.
500 ******************************************************************************************
501 * @ file  : local pointer on file descriptor.
502 *****************************************************************************************/
503void vfs_file_destroy( vfs_file_t *  file ); 
504
505/******************************************************************************************
506 * These functions increment (resp. decrement) the count field in a remote file
507 * descriptor, using a remote_atomic access.
508 *****************************************************************************************/
509void vfs_file_count_up  ( xptr_t   file_xp );
510void vfs_file_count_down( xptr_t   file_xp );
511
512
513
514/*****************************************************************************************/
515/******************* Inode-Tree related functions ****************************************/ 
516/*****************************************************************************************/ 
517
518/******************************************************************************************
519 * This function returns in a kernel buffer allocated by the caller function,
520 * the pathname of a file/dir identified by an extended pointer on the inode.
521 * It traverse the Inode Tree from the target node to the root.
522 * It can be called by any thread running in any cluster.
523 ******************************************************************************************
524 * @ inode_xp    : pointer on inode descriptor.
525 * @ buffer      : kernel buffer for pathname (must be allocated by caller).
526 * @ size        : max number of characters in buffer.
527 * @ return 0 if success / return EINVAL if buffer too small.
528 *****************************************************************************************/
529error_t vfs_get_path( xptr_t    inode_xp,
530                      char    * buffer,
531                      uint32_t  max_size );
532
533/******************************************************************************************
534 * This function takes a pathname (absolute or relative to cwd) and returns an extended
535 * pointer on the associated inode.
536 * - If a given directory name in the path is not found in the inode tree, it try to load
537 *   the missing dentry/inode couple, from informations found in the parent directory.
538 * - If this directory entry does not exist on device, it returns an error.
539 * - If the the file identified by the pathname does not exist on device but the
540 *   flag CREATE is set, the inode is created.
541 * - If the the file identified by the pathname exist on device but both flags EXCL
542 *   and CREATE are set, an error is returned.
543 ******************************************************************************************
544 * @ cwd_xp      : extended pointer on current directory (for relative path).
545 * @ pathname    : path in kernel space (can be relative or absolute).
546 * @ lookup_mode : flags defining the working mode (defined above in this file).
547 * @ inode_xp    : [out] buffer for extended pointer on searched inode.
548 * @ return 0 if success / ENOENT if inode not found , EACCES if permisson denied,
549 *                         EAGAIN if a new complete lookup must be made
550 *****************************************************************************************/
551error_t vfs_lookup( xptr_t             cwd_xp,
552                    char             * pathname,
553                    uint32_t           lookup_mode,
554                                        xptr_t           * inode_xp );
555
556/******************************************************************************************
557 * This function creates a new couple dentry/inode, and insert it in the Inode-Tree.
558 * It can be executed by any thread running in any cluster (can be different from both
559 * the child cluster and the parent cluster), as it uses the rpc_dentry_create_client()
560 * and rpc_inode_create client() if required. This is done in three steps:
561 * 1) The dentry is created in the cluster containing the existing <parent_xp> inode.
562 *    The new dentry name is defined by the <name> argument.
563 * 2) The inode and its associated mapper are created in cluster identified by <child_cxy>.
564 *    The new inode and the parent inode can have different FS types.
565 * 3) The "child_xp" field in created dentry (pointing on the created inode) is updated.
566 ******************************************************************************************
567 * @ child_cxy  : target cluster for child inode.
568 * @ inode_type : new inode type
569 * @ fs_type    : new inode FS type.
570 * @ parent_xp  : extended pointer on parent inode.
571 * @ name       : new directory entry name.
572 * @ extend     : fs_type_specific inode extension.
573 * @ child_xp   : [out] buffer for extended pointer on child inode.
574 * @ return 0 if success / ENOMEM if dentry or inode cannot be created.
575 *****************************************************************************************/
576error_t vfs_add_child_in_parent( cxy_t              child_cxy,
577                                 vfs_inode_type_t   inode_type,
578                                 vfs_fs_type_t      fs_type,
579                                 xptr_t             parent_xp,
580                                 char             * name,   
581                                 void             * extend,
582                                 xptr_t           * child_xp );
583
584/******************************************************************************************
585 * This function removes a couple dentry/inode from the Inode-Tree, and remove it from
586 * the external device.
587 ******************************************************************************************
588 * @ child_xp   : extended pointer on removed inode.
589 *****************************************************************************************/
590error_t vfs_remove_child_from_parent( xptr_t inode_xp );
591
592/******************************************************************************************
593 * This recursive function diplays a complete inode/dentry sub-tree.
594 * Any inode can be selected as the sub-tree root.
595 * TODO this function is not protected against a concurrent inode/dentry removal...
596 ******************************************************************************************
597 * @ inode_xp   : extended pointer on sub-tree root inode.
598 *****************************************************************************************/
599void vfs_display( xptr_t   inode_xp );
600
601
602
603
604
605/*****************************************************************************************/
606/****************** File access API ******************************************************/
607/*****************************************************************************************/
608
609/******************************************************************************************
610 * This function allocates a vfs_file_t structure in the cluster containing the inode
611 * associated to the file identified by the <cwd_xp> & <path> arguments.
612 * It initializes it, register it in the reference process fd_array identified by the
613 * <process> argument, and returns both the extended pointer on the file descriptor,
614 * and the allocated index in the fd_array.
615 * The pathname can be relative to current directory or absolute.
616 * If the inode does not exist in the inode cache, it try to find the file on the mounted
617 * device, and creates an inode on a pseudo randomly selected cluster if found.
618 * It the requested file does not exist on device, it creates a new inode if the
619 * O_CREAT flag is set, and return an error otherwise.
620 ******************************************************************************************
621 * @ process     : local pointer on local process descriptor copy.
622 * @ path        : file pathname (absolute or relative to current directory).
623 * @ flags       : defined above.
624 * @ mode        : access rights (as defined by chmod)
625 * @ file_xp     : [out] buffer for extended pointer on created remote file descriptor.
626 * @ file_id     : [out] buffer for created file descriptor index in reference fd_array.
627 * @ return 0 if success / return non-zero if error.
628 *****************************************************************************************/
629error_t vfs_open( struct process_s * process,
630                          char             * path,
631                          uint32_t           flags,
632                  uint32_t           mode,
633                          xptr_t           * file_xp,
634                          uint32_t         * file_id );
635
636/******************************************************************************************
637 * This function moves <size> bytes between a remote file mapper, identified by the
638 * <file_xp> argument, and a - possibly distributed - user space <buffer>, taken into
639 * account the offset in <file_xp>. The transfer direction is defined by <to_buffer>.
640 * It is called by the sys_read() and sys_write() functions.
641 ******************************************************************************************
642 * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false.
643 * @ file_xp   : extended pointer on the remote file descriptor.
644 * @ buffer    : user space pointer on buffer (can be physically distributed).
645 * @ size      : requested number of bytes from offset.
646 * @ returns number of bytes actually moved if success / -1 if error.
647 *****************************************************************************************/
648int vfs_user_move( bool_t   to_buffer,
649                   xptr_t   file_xp, 
650                   void   * buffer,
651                   uint32_t size );
652
653/******************************************************************************************
654 * This function moves <size> bytes between a remote file mapper, identified by the
655 * <file_xp> argument, and a - possibly remote - kernel <buffer_xp>, taken into
656 * account the offset in <file_xp>. The transfer direction is defined by <to_buffer>.
657 * It is called by the elf_load_process() function.
658 ******************************************************************************************
659 * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false.
660 * @ file_xp   : extended pointer on the remote file descriptor.
661 * @ buffer_xp : user space pointer on buffer (can be physically distributed).
662 * @ size      : requested number of bytes from offset.
663 * @ returns 0 if success / -1 if error.
664 *****************************************************************************************/
665error_t vfs_kernel_move( bool_t   to_buffer,
666                         xptr_t   file_xp, 
667                         xptr_t   buffer_xp,
668                         uint32_t size );
669
670/******************************************************************************************
671 * This function set a new value in the offset of the open file descriptor <file_xp>.
672 * This value depends on the <whence> argument:
673 * - if VFS_SEEK_SET, new value is <offset>
674 * - if VFS_SEEK_CUR, new value is current_offset + <offset>
675 * - if VFS_SEEK_END, new value is file_size + <offset>
676 ******************************************************************************************
677 * @ file_xp   : extended pointer on the remote open file descriptor.
678 * @ offset    : local pointer on source kernel buffer.
679 * @ whence    : VFS_SEEK_SET / VFS_SEEK_CUR / VFS_SEEK_END.
680 * @ new_offset : [out] buffer for new offset value.
681 * @ returns 0 if success / -1 if error.
682 *****************************************************************************************/
683error_t vfs_lseek( xptr_t     file_xp,
684                   uint32_t   offset,
685                   uint32_t   whence, 
686                   uint32_t * new_offset );
687
688/******************************************************************************************
689 * This function close the -non-replicated- file descriptor identified by the <file_xp>
690 * and <file_id> arguments.
691 * 1) All entries in the fd_array copies are directly reset by the calling thread,
692 *    using remote accesses.
693 * 2) The memory allocated to file descriptor in cluster containing the inode is released.
694 *    It requires a RPC if cluster containing the file descriptor is remote.
695 ******************************************************************************************
696 * @ file_xp     : extended pointer on the file descriptor in owner cluster.
697 * @ file_id     : file descriptor index in fd_array.
698 * @ returns 0 if success / -1 if error.
699 *****************************************************************************************/
700error_t vfs_close( xptr_t    file_xp,
701                   uint32_t  file_id );
702
703/******************************************************************************************
704 * This function remove from the file system a directory entry identified by the
705 * <cwd_xp> & <path> arguments.
706 ******************************************************************************************
707 * @ cwd_xp   : extended pointer on the current working directory file descriptor.
708 * @ path     : pathname (absolute or relative to current directory).
709 * @ returns 0 if success / -1 if error.
710 *****************************************************************************************/
711error_t vfs_unlink( xptr_t   cwd_xp,
712                    char   * path );
713
714/******************************************************************************************
715 * This function returns, in the structure pointed by the <k_stat> kernel pointer,
716 * various informations on the file descriptor identified by the <file_xp> argument.
717 * TODO not implemented yet...
718 ******************************************************************************************
719 * @ file_xp    : extended pointer on the file descriptor of the searched directory .
720 * @ k_stat     : local pointer on the stat structure in kernel space.
721 * @ returns 0 if success / -1 if error.
722 *****************************************************************************************/
723error_t vfs_stat( xptr_t        file_xp,
724                  struct stat * k_stat );
725
726/******************************************************************************************
727 * This function returns, in the structure pointed by the <k_dirent> kernel pointer,
728 * various infos on the directory entry currently pointed by the <file_xp> file descriptor.
729 * TODO not implemented yet...
730 ******************************************************************************************
731 * @ file_xp    : extended pointer on the file descriptor of the searched directory .
732 * @ k_dirent   : local pointer on the dirent structure in kernel space.
733 * @ returns 0 if success / -1 if error.
734 *****************************************************************************************/
735error_t vfs_readdir( xptr_t          file_xp,
736                     struct dirent * k_dirent );
737
738/******************************************************************************************
739 * This function  creates a new inode and associated dentry  for the directory defined
740 * by the <cwd_xp> & <path> arguments.
741 * TODO not implemented yet...
742 ******************************************************************************************
743 * @ cwd_xp   : extended pointer on the current working directory file descriptor.
744 * @ path     : pathname (absolute or relative to current directory).                     
745 * @ mode     : access rights (as defined by chmod)
746 * @ returns 0 if success / -1 if error.
747 *****************************************************************************************/
748error_t vfs_mkdir( xptr_t     cwd_xp,
749                   char     * path,
750                   uint32_t   mode );
751
752/******************************************************************************************
753 * This function remove a directory identified by the <cwd_xp / path> arguments
754 * from the file system.
755 * TODO not implemented yet...
756 ******************************************************************************************
757 * @ cwd_xp   : extended pointer on the current working directory file descriptor.
758 * @ path     : pathname (absolute or relative to current directory).                     
759 * @ returns 0 if success / -1 if error.
760 *****************************************************************************************/
761error_t vfs_rmdir( xptr_t   cwd_xp,
762                   char   * path );
763
764/******************************************************************************************
765 * This function makes the directory identified by <cwd_xp / path> arguments to become
766 * the working directory for the calling process.
767 ******************************************************************************************
768 * @ cwd_xp      : extended pointer on current directory file descriptor (relative path).
769 * @ path        : file pathname (absolute or relative to current directory).
770 * return 0 if success / -1 if error.
771 *****************************************************************************************/
772error_t vfs_chdir( xptr_t   cwd_xp,
773                   char   * path );
774
775/******************************************************************************************
776 * This function change the access rigths for the file identified by the <cwd_xp / path>
777 * arguments. The new access rights are defined by the <mode> argument value.
778 ******************************************************************************************
779 * @ cwd_xp      : extended pointer on current directory file descriptor (relative path).
780 * @ path        : file pathname (absolute or relative to current directory).
781 * @ mode        : access rights new value.
782 * return 0 if success / -1 if error.
783 *****************************************************************************************/
784error_t vfs_chmod( xptr_t        cwd_xp,
785                   char        * path,
786                   uint32_t      mode );
787
788/******************************************************************************************
789 * This function creates a named FIFO file.
790 * TODO not implemented yet                                                         
791 ******************************************************************************************
792 * @ path        : FIFO pathname (absolute or relative to current directory).
793 * @ cwd_xp      : extended pointer on the current working directory file descriptor.
794 * @ mode        : access rights new value.
795 *****************************************************************************************/
796error_t vfs_mkfifo( xptr_t       cwd_xp,
797                    char       * path,
798                    uint32_t     mode );
799
800
801/*****************************************************************************************/
802/****************** Mapper access API ****************************************************/
803/*****************************************************************************************/
804
805/******************************************************************************************
806 * This function makes an I/O operation to move one page to/from device from/to the mapper.
807 * It is used in case of MISS on the mapper, or when a dirty page in the mapper must
808 * be updated in the File System.
809 * Depending on the file system type, it calls the proper, FS specific function.
810 * It must be executed by a thread running in the cluster containing the mapper.
811 * The mapper pointer is obtained from the page descriptor.
812 * It takes the mapper lock before launching the IO operation.
813 ******************************************************************************************
814 * @ page      : local pointer on the page descriptor.
815 * @ to_mapper : transfer direction.
816 * @ returns 0 if success / return EINVAL if it cannot access the external device.
817 *****************************************************************************************/
818error_t vfs_mapper_move_page( struct page_s * page,
819                              bool_t          to_mapper );
820
821/******************************************************************************************
822 * This function makes the I/O operations required to move, from device to mapper,
823 * all pages covering a given inode, identified by the <inode> argument. The target
824 * inode can be a directory or a file, but this function is mainly used to load (prefetch)
825 * a complete directory to the mapper.
826 * Depending on the file system type, it calls the proper, FS specific function.
827 * It must be executed by a thread running in the cluster containing the mapper.
828 * The mapper pointer is obtained from the inode descriptor.
829 * It takes the mapper lock before launching the IO operation.
830 ******************************************************************************************
831 * @ inode  : local pointer on inode.
832 * @ return 0 if success / return EIO if device access failure.
833 *****************************************************************************************/
834error_t vfs_mapper_load_all( vfs_inode_t * inode );
835
836
837#endif  /* _VFS_H_ */
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