source: trunk/kernel/fs/vfs.h @ 612

Last change on this file since 612 was 612, checked in by alain, 3 years ago

Fix several bugs in vfs.c, fatfs.c, and devfs.c to support
the <.> and <..> directory entries.

File size: 59.3 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_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
44/****  Forward declarations  ***/
45
46struct vfs_inode_s;
47struct vfs_dentry_s;
48struct vfs_ctx_s;
49struct vfs_file_s;
50
51struct mapper_s;
52struct process_s;
53struct device_s;
54struct vseg_s;
55struct page_s;
56
57/******************************************************************************************
58 * These flags are used to define the working mode of the vfs_lookup() function. 
59 *****************************************************************************************/
60
61#define VFS_LOOKUP_DIR      0x01     /* the searched inode must be a directory           */
62#define VFS_LOOKUP_OPEN         0x02     /* the search is for an open/opendir                */
63#define VFS_LOOKUP_PARENT       0x04     /* return the parent inode (not the inode itself)   */
64#define VFS_LOOKUP_CREATE   0x10     /* file must be created if missing                  */
65#define VFS_LOOKUP_EXCL     0x20     /* file cannot previously exist                     */
66
67/******************************************************************************************
68 * This structure defines a VFS context, that contains informations common to all inodes
69 * and dentries for a given file system. As it is declared as a global variable in the
70 * kdata segment (fs_context[] array), it is replicated in all clusters.
71 * The <extend> field is a pointer on the FS specific context extension.
72 * This extension is dynamically allocated by kernel_init in all clusters.
73 * In each cluster, both this VFS context and the FS specific context are handled as
74 * private by the local OS intance.
75 *****************************************************************************************/
76
77typedef enum
78{
79        FS_TYPE_DEVFS = 0,
80        FS_TYPE_FATFS = 1,
81        FS_TYPE_RAMFS = 2,
82 
83        FS_TYPES_NR   = 3,
84}
85vfs_fs_type_t;
86
87typedef enum
88{
89    CTX_ATTR_READ_ONLY    = 0x01,            /*! write access prohibited                 */
90    CTX_ATTR_SYNC         = 0x10,            /*! synchronise FS on each write            */
91}
92vfs_ctx_attr_t;
93
94typedef struct vfs_ctx_s
95{
96        vfs_fs_type_t  type;                     /*! File System type                        */
97        uint32_t           attr;                     /*! global attributes for all files in FS   */
98        uint32_t       total_clusters;           /*! total number of clusters on device      */
99        uint32_t       cluster_size;             /*! cluster size on device (bytes)          */
100        xptr_t         vfs_root_xp;              /*! extended pointer on VFS root inode      */
101    busylock_t     lock;                     /*! lock protecting inum allocator          */
102    uint32_t       bitmap[BITMAP_SIZE(CONFIG_VFS_MAX_INODES)];  /* inum allocator        */
103    void         * extend;                   /*! FS specific context extension           */
104}
105vfs_ctx_t;
106
107/******************************************************************************************
108 * This structure define a VFS inode.
109 * An inode has several children dentries (if it is a directory), an can have several
110 * parents dentries (if it hass several aliases links):
111 * - The "parents" field is the root of the xlist of parents dentries, and the "links"
112 *   fiels define the number of aliases parent dentries. only a FILE inode can have
113 *   several parents (no hard links for directories).
114 * - The "children" field is an embedded xhtab containing pointers on all local children
115 *   dentries. This set of children is empty for a FILE inode.
116 * Synchronisation:
117 * - the main_lock (remote_rwlock) is used during the inode tree traversal,
118 *   or for inode modification (add/remove children in xhtab).
119 * - the size_lock (remote_rwlock) is used during read/write accesses to the size
120 *   field in the mapper.
121 * - access to the data stored in the associated mapper use the mapper remote_rwlock
122 *   protecting radix tree traversal and modifications.
123 *****************************************************************************************/
124
125/* this enum define the VFS inode types values                                           */
126/* WARNING : this enum must be kept consistent with macros in <shared_stat.h> file       */
127/*           and with types in <shared_dirent.h> file.                                   */
128
129typedef enum   
130{
131    INODE_TYPE_FILE  =     0,           /*! regular file                                 */
132    INODE_TYPE_DIR   =     1,           /*! directory                                    */
133    INODE_TYPE_FIFO  =     2,           /*! POSIX named pipe                             */
134    INODE_TYPE_PIPE  =     3,           /*! POSIX anonymous pipe                         */
135    INODE_TYPE_SOCK  =     4,           /*! POSIX socket                                 */
136    INODE_TYPE_DEV   =     5,           /*! character device                             */
137    INODE_TYPE_BLK   =     6,           /*! block device                                 */
138    INODE_TYPE_SYML  =     7,           /*! symbolic link                                */
139}
140vfs_inode_type_t;
141
142/* this enum define the VFS inode attributes values */
143
144typedef enum 
145{
146    INODE_ATTR_DIRTY   =     0x01,       /* modified versus the value on device          */ 
147    INODE_ATTR_INLOAD  =     0x04,       /* loading from device in progress              */
148    INODE_ATTR_NEW     =     0x08,       /* not saved on device yet                      */
149}
150vfs_inode_attr_t;
151
152typedef struct vfs_inode_s
153{
154        struct vfs_ctx_s * ctx;              /*! local pointer on FS context                 */
155        uint32_t           inum;             /*! inode identifier (unique in file system)    */
156        uint32_t           attr;             /*! inode attributes (see above)                */
157        vfs_inode_type_t   type;             /*! inode type (see above)                      */
158        uint32_t           size;             /*! number of bytes                             */
159        uint32_t           uid;              /*! user owner identifier                       */
160        uint32_t           gid;              /*! group owner identifier                      */
161    uint32_t           rights;           /*! access rights                               */
162        xlist_entry_t      parents;          /*! root of list of parents dentries            */
163        uint32_t           links;            /*! number of parent dentries (hard links)      */
164        xhtab_t            children;         /*! embedded xhtab of children dentries         */
165        remote_rwlock_t    size_lock;        /*! protect read/write to size                  */
166        remote_rwlock_t    main_lock;        /*! protect inode tree traversal and modifs     */
167//  list_entry_t       list;             /*! member of set of inodes in same cluster     */
168//  list_entry_t       wait_root;        /*! root of threads waiting on this inode       */
169        struct mapper_s  * mapper;           /*! associated file cache                       */
170        void             * extend;           /*! fs_type_specific inode extension            */
171}
172vfs_inode_t;
173
174/* This define the masks for the inode <rights> field  */
175
176#define VFS_ISUID          0x0004000
177#define VFS_ISGID          0x0002000
178#define VFS_ISVTX          0x0001000
179
180#define VFS_IRWXU      0x0000700
181#define VFS_IRUSR      0x0000400
182#define VFS_IWUSR      0x0000200
183#define VFS_IXUSR      0x0000100
184
185#define VFS_IRWXG      0x0000070
186#define VFS_IRGRP      0x0000040
187#define VFS_IWGRP      0x0000020
188#define VFS_IXGRP      0x0000010
189
190#define VFS_IRWXO      0x0000007
191#define VFS_IROTH      0x0000004
192#define VFS_IWOTH      0x0000002
193#define VFS_IXOTH      0x0000001
194
195/******************************************************************************************
196 * This structure defines a directory entry.
197 * A dentry contains the name of a remote file/dir, an extended pointer on the
198 * inode representing this file/dir, a local pointer on the inode representing
199 * the parent directory.
200 * A dentry can be member of the set of children of a given directory inode (xhtab).
201 * A dentry can be member of the set of parents  of a given inode (xlist).
202 *****************************************************************************************/
203
204typedef struct vfs_dentry_s
205{
206    struct vfs_ctx_s   * ctx;            /*! local pointer on FS context                 */
207        char                 name[CONFIG_VFS_MAX_NAME_LENGTH];
208        uint32_t             length;         /*! name length (bytes)                         */
209    struct vfs_inode_s * parent;         /*! local pointer on parent inode               */
210    xptr_t               child_xp;       /*! extended pointer on child inode             */
211    xlist_entry_t        children;       /*! member of set of children dentries          */
212    xlist_entry_t        parents;        /*! member of set of parent dentries            */
213        void               * extend;         /*! FS specific extension                       */
214}
215vfs_dentry_t;
216
217/******************************************************************************************
218 * This file structure describes an open file/directory for a given process.
219 * It is not replicated, and is dynamically allocated in the cluster that contains
220 * the inode, when a thread makes an open() or opendir() system call.
221 * It cannot exist a file structure without an inode structure in same cluster.
222 * As the fd_array (containing extended pointers on the open file descriptors)
223 * is replicated in all process descriptors, we need a references counter.
224 *****************************************************************************************/
225
226typedef enum
227{
228    FD_ATTR_READ_ENABLE    = 0x01,     /*! read access possible                         */
229    FD_ATTR_WRITE_ENABLE   = 0x02,     /*! write access possible                        */
230    FD_ATTR_APPEND         = 0x04,     /*! append on each write                         */
231    FD_ATTR_CLOSE_EXEC     = 0x08,     /*! close file on exec                           */
232    FD_ATTR_SYNC           = 0x10,     /*! synchronise FS on each write                 */
233    FD_ATTR_IS_DIR         = 0x20,     /*! this is a directory                          */
234}
235vfs_file_attr_t;
236
237typedef struct vfs_file_s
238{
239        struct vfs_ctx_s      * ctx;        /*! local pointer on FS context.                 */
240        uint32_t                gc;         /*! generation counter                           */
241        vfs_file_attr_t         attr;       /*! file attributes bit vector (see above)       */
242        vfs_inode_type_t        type;       /*! same type as inode                           */
243        uint32_t                offset;     /*! seek position in file                        */
244        uint32_t                refcount;   /*! all pointers on this file descriptor         */
245        remote_rwlock_t         lock;       /*! protect offset modifications                 */
246        struct mapper_s       * mapper;     /*! associated file cache                        */
247        struct vfs_inode_s    * inode;      /*! local pointer on associated inode            */
248        void                  * extend;     /*! FS specific extension                        */
249}
250vfs_file_t;
251
252
253/******************************************************************************************
254 *        These functions access / modify  a VFS context.
255 *****************************************************************************************/
256
257/******************************************************************************************
258 * This function initialise a (statically allocated) VFS context in local cluster.
259 ******************************************************************************************
260 * @ fs_type        : file system type.
261 * @ attr           : global attributes (for all files in FS.
262 * @ total_clusters : total number of clusters on device.
263 * @ cluster_size   : cluster size on device (bytes).
264 * @ vfs_root_xp    : extended pointer on VFS root inode.
265 * @ extend         : fs_type_specific extension.
266 *****************************************************************************************/
267void vfs_ctx_init( vfs_fs_type_t   type,
268                   uint32_t        attr,
269                       uint32_t        total_clusters,
270                       uint32_t        cluster_size,
271                       xptr_t          vfs_root_xp,
272                   void          * extend );
273
274/******************************************************************************************
275 * This function allocates an inode identifier from the local cluster inum allocator.
276 * The inum respects a fixed format:
277 * - the 16 MSB bits contain the cluster identifier : cxy
278 * - the 16 LSB bits contains the local inode identifier  : lid
279 ******************************************************************************************
280 * @ ctx      : local pointer on file system context.
281 * @ inum     : [ou] buffer for allocated inode identifier.
282 * @ return 0 if success / return non-zero if error.
283 *****************************************************************************************/
284error_t vfs_ctx_inum_alloc( vfs_ctx_t * ctx,
285                            uint32_t  * inum );
286
287/******************************************************************************************
288 * This function release an inode identifier.                                 
289 ******************************************************************************************
290 * @ ctx      : local pointer on file system context.
291 * @ inum     : released inode identifier.
292 *****************************************************************************************/
293void vfs_ctx_inum_release( vfs_ctx_t * ctx,
294                           uint32_t    inum );
295
296
297
298/******************************************************************************************
299 *        These low-level functions access / modify a VFS inode descriptor
300 *****************************************************************************************/
301
302/******************************************************************************************
303 * This function returns a printable string for the inode type.
304 *****************************************************************************************/
305const char * vfs_inode_type_str( vfs_inode_type_t type );
306
307/******************************************************************************************
308 * This function allocates memory from local cluster for an inode descriptor and the
309 * associated mapper. It initialise these descriptors from arguments values.
310 * It must called by a local thread. Use the RPC_INODE_CREATE if client thread is remote.
311 ******************************************************************************************
312 * @ fs_type    : file system type.
313 * @ inode_type : inode type.
314 * @ attr       : inode attributes.
315 * @ rights     : inode access rights.
316 * @ uid        : user owner ID.
317 * @ gid        : group owner ID.
318 * @ inode_xp   : [out] buffer for extended pointer on created inode.
319 * @ return 0 if success / return ENOMEM or EINVAL if error.
320 *****************************************************************************************/
321error_t vfs_inode_create( vfs_fs_type_t     fs_type,
322                          vfs_inode_type_t  inode_type,
323                          uint32_t          attr,
324                          uint32_t          rights,
325                          uid_t             uid,
326                          gid_t             gid,
327                          xptr_t          * inode_xp );
328
329/******************************************************************************************
330 * This function releases memory allocated to an inode descriptor, including
331 * all memory allocated to the mapper (both mapper descriptor and radix tree).
332 * The mapper should not contain any dirty page (should be synchronized before deletion).
333 * It must be executed by a thread running in the cluster containing the inode.
334 * Use the rpc_vfs_inode_destroy_client() function if required.
335 ******************************************************************************************
336 * @ inode  : local pointer on inode descriptor.
337 *****************************************************************************************/
338void vfs_inode_destroy( vfs_inode_t *  inode ); 
339
340/******************************************************************************************
341 * This function returns the <size> of a file/dir from a remote inode,
342 * taking the remote_rwlock protecting <size> in READ_MODE.
343 *****************************************************************************************
344 * @ inode_xp  : extended pointer on the remote inode.
345 * @ return the current size.
346 *****************************************************************************************/
347uint32_t vfs_inode_get_size( xptr_t inode_xp );
348
349/******************************************************************************************
350 * This function set the <size> of a file/dir to a remote inode,
351 * taking the remote_rwlock protecting <size> in WRITE_MODE.
352 *****************************************************************************************
353 * @ inode_xp  : extended pointer on the remote inode.
354 * @ size      : value to be written.
355 *****************************************************************************************/
356void vfs_inode_set_size( xptr_t   inode_xp,
357                         uint32_t size );
358
359/******************************************************************************************
360 * This function takes the main lock of a remote inode.
361 * This lock protect all inode fields, including the children dentries.
362 *****************************************************************************************
363 * @ inode_xp  : extended pointer on the remote inode.
364 *****************************************************************************************/
365void vfs_inode_lock( xptr_t inode_xp );
366
367/******************************************************************************************
368 * This function releases the main lock of a remote inode.
369 * This lock protect all inode fiels, including the children dentries.
370 *****************************************************************************************
371 * @ inode_xp  : extended pointer on the remote inode.
372 *****************************************************************************************/
373void vfs_inode_unlock( xptr_t inode_xp );
374
375/******************************************************************************************
376 * This debug function copies the name of a remote inode identified by the <inode_xp>
377 * argument to a local buffer identified by the <name> argument.
378 * The local buffer size must be at least CONFIG_VFS_MAX_NAME_LENGTH.
379 *****************************************************************************************
380 * @ inode_xp  : extended pointer on the remote inode.
381 * @ name      : local buffer pointer.
382 *****************************************************************************************/
383void vfs_inode_get_name( xptr_t inode_xp,
384                         char * name );
385
386/******************************************************************************************
387 * This function accesses successively all pages of a file identified by the <inode>,
388 * argument, to force misses, and load all pages into mapper.
389 * The target inode can be a directory or a file, but this function is mainly used
390 * to prefetch a complete directory to the mapper.
391 * It must be executed by a thread running in the cluster containing the inode.
392 * This function does NOT take any lock.
393 ******************************************************************************************
394 * @ inode  : local pointer on inode.
395 * @ return 0 if success / return -1 if device access failure.
396 *****************************************************************************************/
397error_t vfs_inode_load_all_pages( vfs_inode_t * inode );
398
399
400
401/******************************************************************************************
402 *        These low-level functions access / modify a VFS dentry descriptor
403 *****************************************************************************************/
404
405/******************************************************************************************
406 * This function allocates memory from local cluster for a dentry descriptor,
407 * initialises it from  arguments values, and returns the extended pointer on dentry.
408 * It must called by a local thread. Use the RPC_DENTRY_CREATE if client thread is remote.
409 ******************************************************************************************
410 * @ fs_type    : file system type.
411 * @ name       : directory entry file/dir name.
412 * @ dentry_xp  : [out] buffer for extended pointer on created dentry.
413 * @ return 0 if success / return ENOMEM or EINVAL if error.
414 *****************************************************************************************/
415error_t vfs_dentry_create( vfs_fs_type_t   fs_type,
416                           char          * name,
417                           xptr_t        * dentry_xp );
418 
419/******************************************************************************************
420 * This function removes the dentry from the parent inode xhtab, and releases the memory
421 * allocated to the dentry descriptor.
422 * It must be executed by a thread running in the cluster containing the dentry.
423 * Use the rpc_vfs_dentry_destroy_client() function if required.
424 ******************************************************************************************
425 * @ dentry  : local pointer on dentry descriptor.
426 *****************************************************************************************/
427void vfs_dentry_destroy( vfs_dentry_t *  dentry ); 
428
429
430/******************************************************************************************
431 *        These low-level functions access / modify a VFS file descriptor
432 *****************************************************************************************/
433
434/******************************************************************************************
435 * This function allocates memory and initializes a new local file descriptor.
436 * It must be executed in the cluster containing the inode.
437 * If the client thread is not running in the owner cluster, it must use the
438 * rpc_vfs_file_create_client() function.
439 ******************************************************************************************
440 * @ inode    : local pointer on associated inode.
441 * @ attr     : file descriptor attributes.
442 * @ file_xp  : [out] buffer for extended pointer on created file descriptor.
443 * @ return 0 if success / return ENOMEM if error.
444 *****************************************************************************************/
445error_t vfs_file_create( vfs_inode_t * inode,
446                         uint32_t      attr,
447                         xptr_t      * file_xp ); 
448
449/******************************************************************************************
450 * This function releases memory allocated to a local file descriptor.
451 * It must be executed by a thread running in the cluster containing the inode,
452 * and the file refcount must be zero.
453 * If the client thread is not running in the owner cluster, it must use the
454 * rpc_vfs_file_destroy_client() function.
455 ******************************************************************************************
456 * @ file  : local pointer on file descriptor.
457 *****************************************************************************************/
458void vfs_file_destroy( vfs_file_t *  file ); 
459
460/******************************************************************************************
461 * These functions increment (resp. decrement) the count field in a remote file
462 * descriptor, using a remote_atomic access.
463 *****************************************************************************************/
464void vfs_file_count_up  ( xptr_t   file_xp );
465void vfs_file_count_down( xptr_t   file_xp );
466
467
468
469
470/******************************************************************************************
471 *        These functions access / modify the distributed VFS Inode Tree
472 *****************************************************************************************/
473
474/******************************************************************************************
475 * This function returns in a kernel <buffer> allocated by the caller function,
476 * the pathname of a file/dir identified by the <inode_xp> argument.
477 * It traverse the Inode Tree from the target node to the root.
478 * It can be called by any thread running in any cluster.
479 * As this buffer if filled in "reverse order" (i.e. from the target inode to the root),
480 * the pathname is stored in the higher part of the buffer.
481 * A pointer on the first character of the pathname is returned in <first> buffer.
482 *
483 * WARNING : This function takes & releases the remote_rwlock protecting the Inode Tree.
484 ******************************************************************************************
485 * @ inode_xp    : [in]  extended pointer on target inode descriptor.
486 * @ buffer      : [in]  kernel buffer for pathname (allocated by caller).
487 * @ first       : [out] pointer on first character in buffer.
488 * @ max_size    : [in]  max number of characters in buffer.
489 * @ return 0 if success / return EINVAL if buffer too small.
490 *****************************************************************************************/
491error_t vfs_get_path( xptr_t    inode_xp,
492                      char    * buffer,
493                      char   ** first,
494                      uint32_t  max_size );
495
496/******************************************************************************************
497 * This function traverses the the Inode Tree, from inode identified by the <root_xp>
498 * argument, and returns in <inode_xp> the inode identified by the < pathname> argument.
499 * It can be called by a thread running in any cluster.
500 * It supports the following flags that define the lookup modes :
501 * - VFS_LOOKUP_DIR    : the searched inode must be a directory
502 * - VFS_LOOKUP_OPEN   : the search is for an open/opendir
503 * - VFS_LOOKUP_PARENT : return the parent inode (not the inode itself)
504 * - VFS_LOOKUP_CREATE : file/directory must be created if missing on IOC
505 * - VFS_LOOKUP_EXCL   : file cannot previously exist
506 * As the inode Tree is a cache, the search policy is the following :
507 * - If a given directory name in the path is not found in the inode tree, it try to load
508 *   the missing dentry/inode couple, from informations found in the parent directory.
509 * - If this directory entry does not exist on IOC, it returns an error.
510 * - If the the file identified by the pathname does not exist on IOC but the
511 *   flag CREATE is set, the inode is created. It returns an error otherwise.
512 * - If the the file identified by the pathname exist on device, but both flags EXCL
513 *   and CREATE are set, an error is returned.
514 * - If the PARENT flag is set, it returns in <inode_xp> an extended pointer on the parent
515 *   inode, and copies in <last_name> buffer a string containing the last name in path.
516 *
517 * WARNING : The remote_rwlock protecting the Inode Tree must be taken by the caller.
518 *
519 * TODO the access rights are not checked yet.
520 ******************************************************************************************
521 * @ root_xp     : [in]  extended pointer on root inode (can be root of a subtree).
522 * @ pathname    : [in]  path (can be relative or absolute).
523 * @ lookup_mode : [in]  flags defining the searching mode.
524 * @ inode_xp    : [out] buffer for extended pointer on searched inode.
525 * @ last_name   : [out] pointer on buffer for last name in path.
526 * @ return 0 if success / ENOENT if inode not found , EACCES if permisson denied,
527 *****************************************************************************************/
528error_t vfs_lookup( xptr_t             root_xp,
529                    char             * pathname,
530                    uint32_t           lookup_mode,
531                                        xptr_t           * inode_xp,
532                    char             * last_name );
533
534/******************************************************************************************
535 * This function creates a new couple dentry/inode, and insert it in the Inode-Tree.
536 * Only the distributed Inode Tree is modified: it does NOT modify the parent mapper,
537 * and does NOT update the FS on IOC device.
538 * It can be executed by any thread running in any cluster (can be different from both
539 * the child cluster and the parent cluster).
540 *
541 * [Implementation]
542 * As there are cross-references between inode and dentry, this function implements
543 * a three steps scenario :
544 * 1) The dentry descriptor is created in the cluster containing the existing <parent_xp>
545 *    inode, and partially initialized, using the RPC_VFS_CREATE DENTRY if required.
546 * 2) The inode and its associated mapper are created in cluster identified by <child_cxy>,
547 *    and partially initialised, using the RPC_VFS_CREATE_INODE if required.
548 *    The new inode and the parent inode can have different FS types.
549 * 3) The pointers between the parent inode, the new dentry, and the child inode
550 *    are updated, using remote accesses.
551 ******************************************************************************************
552 * @ child_inode_cxy  : [in]  target cluster for child inode.
553 * @ child_inode_type : [in]  child inode type
554 * @ fs_type          : [in]  child inode FS type.
555 * @ parent_inode_xp  : [in]  extended pointer on parent inode.
556 * @ name             : [in]  new directory entry name.
557 * @ dentry_xp        : [out] buffer for extended pointer on dentry
558 * @ child_inode_xp   : [out] buffer for extended pointer on child inode.
559 * @ return 0 if success / -1 if dentry or inode cannot be created.
560 *****************************************************************************************/
561error_t vfs_add_child_in_parent( cxy_t              child_inode_cxy,
562                                 vfs_inode_type_t   child_inode_type,
563                                 vfs_fs_type_t      fs_type,
564                                 xptr_t             parent_inode_xp,
565                                 char             * name,
566                                 xptr_t           * dentry_xp,   
567                                 xptr_t           * child_inode_xp );
568
569/******************************************************************************************
570 * This function removes a remote dentry from the Inode-Tree.
571 * - It removes the dentry from the parent inode xhtab ("children" field), and from the
572 *   child inode xlist ("parents" field).
573 * - It releases the memory allocated to the dentry descriptor.
574 * - If the number of parents of the child inode is one, it also releases the memory
575 *   allocated to the child inode.
576 * Only the Inode Tree is modified: it does NOT modify the parent mapper,
577 * and does NOT update the FS on IOC device.
578 * It can be executed by any thread running in any cluster (can be different from both
579 * the inode cluster and the dentry cluster).
580 ******************************************************************************************
581 * @ dentry_xp   : extended pointer on removed dentry.
582 *****************************************************************************************/
583void vfs_remove_child_from_parent( xptr_t dentry_xp );
584
585/******************************************************************************************
586 * This function is called by the vfs_lookup() function when a new dentry/inode must
587 * be created from scratch and introduced in both the Inode Tree and the IOC device.
588 * The dentry and inode descriptors have been created by the caller:
589 * - It allocates one cluster from the relevant FS, and updates the File Allocation
590 *   Table (both the FAT mapper, and the IOC device).
591 * - It set the "size", and "extend" fields in child inode descriptor.
592 * - It updates the parent directory to introduce the new child in the parent directory
593 *   inode descriptor (radix tree), in theparent inode mapper, and on IOC device.
594 * - It set the "extend" field in dentry descriptor.
595 * It can be called by a thread running in any cluster.
596 ******************************************************************************************
597 * @ parent_xp   : extended pointer on parent inode descriptor.
598 * @ dentry_xp   : extended pointer on new dentry descriptor.
599 * @ child_xp    : extended pointer on child inode descriptor.
600 * @ return 0 if success / -1 if failure.
601 *****************************************************************************************/
602error_t vfs_new_dentry_init( xptr_t   parent_xp,
603                             xptr_t   dentry_xp,
604                             xptr_t   child_xp );
605
606/******************************************************************************************
607 * This function creates in the directory identified by the <child_xp> argument,
608 * the two special dentries <.> and <..>. The parent directory inode is defined
609 * by the <parent_xp> argument. The two dentries are introduced in the Inode Tree.
610 * They are also introduced in the child directory mapper, and the IOC device is updated.
611 * This function is called by all functions creating a brand new directory : vfs_mkdir(),
612 * devfs_global_init(), and devfs_local_init().
613 ******************************************************************************************
614 * @ child_xp    : extended pointer on new directory inode.
615 * @ parent_xp   : extended pointer on parent directory inode.
616 * @ return 0 if success / -1 if failure.
617 *****************************************************************************************/
618error_t vfs_add_special_dentries( xptr_t  child_xp,
619                                  xptr_t  parent_xp );
620
621/******************************************************************************************
622 * This recursive function diplays a complete inode/dentry sub-tree.
623 * Any inode can be selected as the sub-tree root.
624 * WARNING : this function is not protected against a concurrent inode/dentry removal...
625 ******************************************************************************************
626 * @ inode_xp   : extended pointer on sub-tree root inode.
627 *****************************************************************************************/
628void vfs_display( xptr_t   inode_xp );
629
630/******************************************************************************************
631 * This function mount a given file system type for a given process
632 * TODO non implemented yet [AG].     
633 *****************************************************************************************/
634error_t vfs_mount_fs_root( struct device_s  * device,
635                                       uint32_t           fs_type,
636                                       struct process_s * process );
637
638
639
640
641/******************************************************************************************
642 *        These functions define the VFS "syscalls" API (user commands)
643 *****************************************************************************************/
644
645/******************************************************************************************
646 * This function moves <size> bytes between a remote file mapper, identified by the
647 * <file_xp> argument, and a - possibly distributed - user space <buffer>, taken into
648 * account the offset in <file_xp>. The transfer direction is defined by <to_buffer>.
649 * It is called by the sys_read() and sys_write() functions.
650 ******************************************************************************************
651 * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false.
652 * @ file_xp   : extended pointer on the remote file descriptor.
653 * @ buffer    : user space pointer on buffer (can be physically distributed).
654 * @ size      : requested number of bytes from offset.
655 * @ returns number of bytes actually moved if success / -1 if error.
656 *****************************************************************************************/
657int vfs_user_move( bool_t   to_buffer,
658                   xptr_t   file_xp, 
659                   void   * buffer,
660                   uint32_t size );
661
662/******************************************************************************************
663 * This function moves <size> bytes between a remote file mapper, identified by the
664 * <file_xp> argument, and a - possibly remote - kernel <buffer_xp>, taken into
665 * account the offset in <file_xp>. The transfer direction is defined by <to_buffer>.
666 * It is called by the elf_load_process() function.
667 ******************************************************************************************
668 * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false.
669 * @ file_xp   : extended pointer on the remote file descriptor.
670 * @ buffer_xp : user space pointer on buffer (can be physically distributed).
671 * @ size      : requested number of bytes from offset.
672 * @ returns 0 if success / -1 if error.
673 *****************************************************************************************/
674error_t vfs_kernel_move( bool_t   to_buffer,
675                         xptr_t   file_xp, 
676                         xptr_t   buffer_xp,
677                         uint32_t size );
678
679/******************************************************************************************
680 * This function allocates a vfs_file_t structure in the cluster containing the inode
681 * identified by the <root_xp> & <path> arguments.
682 * It initializes it, register it in the reference process fd_array identified by the
683 * <process_xp> argument, and returns both the extended pointer on the file descriptor,
684 * and the allocated index in the <file_xp> and <file_id> buffers.
685 * The pathname can be relative to current directory or absolute.
686 * If the inode does not exist in the inode cache, it try to find the file on the IOC
687 * device, and creates an inode on a pseudo randomly selected cluster if found.
688 * It the requested file does not exist on device, it creates a new inode if the
689 * O_CREAT flag is set, and return an error otherwise.
690 *
691 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
692 ******************************************************************************************
693 * @ root_xp     : extended pointer on path root inode.
694 * @ path        : file pathname (absolute or relative to current directory).
695 * @ process_xp  : extended pointer on client reference process.
696 * @ flags       : defined in vfs_file_t structure.
697 * @ mode        : access rights (as defined by chmod).
698 * @ file_xp     : [out] buffer for extended pointer on created remote file descriptor.
699 * @ file_id     : [out] buffer for created file descriptor index in reference fd_array.
700 * @ return 0 if success / return non-zero if error.
701 *****************************************************************************************/
702error_t vfs_open( xptr_t             root_xp,
703                          char             * path,
704                  xptr_t             process_xp,
705                          uint32_t           flags,
706                  uint32_t           mode,
707                          xptr_t           * file_xp,
708                          uint32_t         * file_id );
709
710/******************************************************************************************
711 * This function set a new value in the offset of the open file descriptor <file_xp>.
712 * This value depends on the <whence> argument:
713 * - if VFS_SEEK_SET, new value is <offset>
714 * - if VFS_SEEK_CUR, new value is current_offset + <offset>
715 * - if VFS_SEEK_END, new value is file_size + <offset>
716 ******************************************************************************************
717 * @ file_xp   : extended pointer on the remote open file descriptor.
718 * @ offset    : local pointer on source kernel buffer.
719 * @ whence    : VFS_SEEK_SET / VFS_SEEK_CUR / VFS_SEEK_END.
720 * @ new_offset : [out] buffer for new offset value.
721 * @ returns 0 if success / -1 if error.
722 *****************************************************************************************/
723error_t vfs_lseek( xptr_t     file_xp,
724                   uint32_t   offset,
725                   uint32_t   whence, 
726                   uint32_t * new_offset );
727
728/******************************************************************************************
729 * This function close the - non-replicated - file descriptor identified by the <file_xp>
730 * and <file_id> arguments.
731 * 1) All entries in the fd_array copies are directly reset by the calling thread,
732 *    using remote accesses.
733 * 2) The memory allocated to file descriptor in cluster containing the inode is released.
734 *    It requires a RPC if cluster containing the file descriptor is remote.
735 ******************************************************************************************
736 * @ file_xp     : extended pointer on the file descriptor in owner cluster.
737 * @ file_id     : file descriptor index in fd_array.
738 * @ returns 0 if success / -1 if error.
739 *****************************************************************************************/
740error_t vfs_close( xptr_t    file_xp,
741                   uint32_t  file_id );
742
743/******************************************************************************************
744 * This function is called by the kernel to create in the file system a new directory
745 * identified by the <root_xp> & <path> arguments, with the access permission defined
746 * by the <rights> argument. All nodes in the path - but the last -  must exist.
747 *
748 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
749 ******************************************************************************************
750 * @ root_xp : extended pointer on path root inode (any inode in Inode Tree).
751 * @ path    : pathname (absolute or relative to current directory).
752 * @ rights  : access rights.
753 * @ returns 0 if success / -1 if error.
754 *****************************************************************************************/
755error_t vfs_mkdir( xptr_t   root_xp,
756                   char   * path,
757                   uint32_t rights );
758
759/******************************************************************************************
760 * This function is called by the kernel to create in the file system a new directory
761 * entry identified by the <new_root_xp> & <new_path> arguments, to be linked to an
762 * existing inode, identified by the  <old_root_xp> & <old_path> arguments.
763 * If the link is successful, the link count of the target inode is incremented.
764 * The <new_path> and <old_path> share equal access rights to the underlying inode.
765 * Both the IOC device and the Inode Tree are modified.
766 $
767 * TODO This function should handle any type of node, but the current implementation
768 * handles only the FILE and DIR types.
769 *
770 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
771 ******************************************************************************************
772 * @ old_root_xp : extended pointer on old path root inode (any inode in Inode Tree).
773 * @ old_path    : old pathname (absolute or relative to current directory).
774 * @ nld_root_xp : extended pointer on new path root inode (any inode in Inode Tree).
775 * @ new_path    : new pathname (absolute or relative to current directory).
776 * @ returns 0 if success / -1 if error.
777 *****************************************************************************************/
778error_t vfs_link( xptr_t   old_root_xp,
779                  char   * old_path,
780                  xptr_t   new_root_xp,
781                  char   * new_path );
782
783/******************************************************************************************
784 * This function is called by the kernel to remove from the file system a directory entry
785 * identified by the  <root_xp> & <path> arguments.
786 * The link count of the target node is decremented.
787 * If the removed link is the last, the target inode is deleted.
788 * Both the IOC device and the Inode Tree are modified.
789 *
790 * TODO This function should handle any type of node, but the current implementation
791 * handles only only the FILE and DIR types.
792 *
793 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
794 ******************************************************************************************
795 * @ root_xp  : extended pointer on root inode (can be any inode in Inode Tree).
796 * @ path     : pathname (absolute or relative to current directory).
797 * @ returns 0 if success / -1 if error.
798 *****************************************************************************************/
799error_t vfs_unlink( xptr_t   root_xp,
800                    char   * path );
801
802/******************************************************************************************
803 * This function returns, in the structure pointed by the <st> pointer, various
804 * informations on the inode identified by the <root_inode_xp> and <patname> arguments.
805 *
806 * TODO : only partially implemented yet (only size and inum fields).
807 *
808 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
809 ******************************************************************************************
810 * @ root_xp    : extended pointer on path root inode (any inode in Inode Tree)
811 * @ pathname   : pathname to target inode.
812 * @ st         : local pointer on the stat structure in kernel space.
813 * @ returns 0 if success / -1 if error.
814 *****************************************************************************************/
815error_t vfs_stat( xptr_t        root_xp,
816                  char        * pathname,
817                  struct stat * st );
818
819/******************************************************************************************
820 * This function  creates a new directory as defined by the <root_xp> & <path> arguments.
821 * TODO not implemented yet...
822 ******************************************************************************************
823 * @ root_xp  : extended pointer on the path root directory.
824 * @ path     : pathname (absolute or relative to CWD).                     
825 * @ mode     : access rights (as defined by chmod)
826 * @ returns 0 if success / -1 if error.
827 *****************************************************************************************/
828error_t vfs_mkdir( xptr_t     root_xp,
829                   char     * path,
830                   uint32_t   mode );
831
832/******************************************************************************************
833 * This function makes the directory identified by the <root_xp and <path> arguments
834 * to become the working directory for the calling process.
835 ******************************************************************************************
836 * @ root_xp  : extended pointer on the path root directory.
837 * @ path     : pathname (absolute or relative to CWD).
838 * return 0 if success / -1 if error.
839 *****************************************************************************************/
840error_t vfs_chdir( xptr_t   root_xp,
841                   char   * path );
842
843/******************************************************************************************
844 * This function change the access rigths for the file/directory identified by the
845 * <root_xp> and <path> arguments as defined by the <mode> argument value.
846 ******************************************************************************************
847 * @ root_xp  : extended pointer on the path root directory.
848 * @ path     : pathname (absolute or relative to CWD).
849 * @ mode     : access rights
850 * return 0 if success / -1 if error.
851 *****************************************************************************************/
852error_t vfs_chmod( xptr_t        root_xp,
853                   char        * path,
854                   uint32_t      mode );
855
856/******************************************************************************************
857 * This function creates a named FIFO file.
858 * TODO not implemented yet                                                         
859 ******************************************************************************************
860 * @ root_xp  : extended pointer on the path root directory.
861 * @ path     : pathname (absolute or relative to CWD).
862 * @ mode     : access rights new value.
863 *****************************************************************************************/
864error_t vfs_mkfifo( xptr_t       root_xp,
865                    char       * path,
866                    uint32_t     mode );
867
868
869
870
871
872/******************************************************************************************
873 *        These functions define the VFS "FS" API to a specific File System
874 *****************************************************************************************/
875
876/******************************************************************************************
877 * This function updates the mapper associated to a directory inode identified by the
878 * <parent> argument, to add a new entry identified by the <dentry> argument.
879 * The directory inode descriptor and the dentry descriptor are in the same cluster.
880 * Depending on the file system type, it calls the proper, FS specific function.
881 * It also updates the dentry descriptor and/or the inode descriptor extensions
882 * as required by the specific file system type.
883 * Finally, it synchronously updates the parent directory on IOC device.
884 *
885 * It must be executed by a thread running in the cluster containing the parent directory.
886 * It can be the RPC_VFS_FS_ADD_DENTRY. This function does NOT take any lock.
887 ******************************************************************************************
888 * @ parent  : local pointer on parent (directory) inode.
889 * @ dentry  : local pointer on dentry containing name.
890 * @ return 0 if success / return -1 if device access failure.
891 *****************************************************************************************/
892error_t vfs_fs_add_dentry( vfs_inode_t  * parent,
893                           vfs_dentry_t * dentry );
894
895/******************************************************************************************
896 * This function updates the mapper associated to a directory inode identified by the
897 * <parent> argument, to remove an entry identified by the <dentry> argument.
898 * The directory inode descriptor and the dentry descriptor are in the same cluster.
899 * Depending on the file system type, it calls the proper, FS specific function.
900 * Finally, it synchronously updates the parent directory on IOC device.
901 *
902 * It must be executed by a thread running in the cluster containing the parent directory.
903 * It can be the RPC_VFS_VS_REMOVE_DENTRY. This function does NOT take any lock.
904 ******************************************************************************************
905 * @ parent  : local pointer on parent (directory) inode.
906 * @ dentry  : local pointer on dentry containing name.
907 * @ return 0 if success / return -1 if device access failure.
908 *****************************************************************************************/
909error_t vfs_fs_remove_dentry( vfs_inode_t  * parent,
910                              vfs_dentry_t * dentry );
911
912/******************************************************************************************
913 * This function scan the mapper of an an existing parent inode directory, identified by
914 * the <parent> argument to find a directory entry identified by the <name> argument,
915 * and updates both the child inode descriptor, identified by the <child_xp> argument,
916 * and the associated dentry descriptor :
917 * - It set the "size", and "extend" fields in inode descriptor.
918 * - It set the "extend" field in dentry descriptor.
919 * It is called by the vfs_lookup() function in case of miss.
920 *
921 * Depending on the file system type, it calls the relevant, FS specific function.
922 * It must be called by a thread running in the cluster containing the parent inode.
923 * This function does NOT take any lock.
924 ******************************************************************************************
925 * @ parent    : local pointer on parent inode (directory).
926 * @ name      : child name.
927 * @ child_xp  : extended pointer on remote child inode (file or directory)
928 * @ return 0 if success / return ENOENT if not found.
929 *****************************************************************************************/
930error_t vfs_fs_get_dentry( vfs_inode_t * parent,
931                           char        * name,
932                           xptr_t        child_xp );
933
934/******************************************************************************************
935 * This function scan the mapper of an an existing parent inode directory, identified by
936 * the <inode> argument and copy up to <max_dirent> valid dentries to a
937 * local dirent array, defined by the <array> argument. The <min_dentry> argument defines
938 * the index of the first dentry to copied to the target dirent array.
939 * This function returns in the <entries> buffer the number of dentries actually written,
940 * and signals in the <done> buffer when the last valid entry has been found.
941 * If the <detailed> argument is true, a dentry/inode couple that does not exist in
942 * the Inode Tree is dynamically created, and all dirent fiels are documented in the
943 * dirent array. Otherwise, only the dentry name is documented.
944 *
945 * Depending on the file system type, it calls the relevant, FS specific function.
946 * It must be called by a thread running in the cluster containing the parent inode.
947 * This function does NOT take any lock.
948 ******************************************************************************************
949 * @ inode      : [in]  local pointer on directory inode.
950 * @ array      : [in]  local pointer on array of dirents.
951 * @ max_dirent : [in]  max number of slots in dirent array.
952 * @ min_dentry : [in]  index of first dentry to be copied into array.
953 * @ detailed   : [in]  dynamic inode creation if true.
954 * @ entries    : [out] number of dentries actually copied into array.
955 * @ done       : [out] Boolean true when last entry found.
956 * @ return 0 if success / return -1 if failure.
957 *****************************************************************************************/
958error_t vfs_fs_get_user_dir( vfs_inode_t   * inode,
959                             struct dirent * array,
960                             uint32_t        max_dirent,
961                             uint32_t        min_dentry,
962                             bool_t          detailed,
963                             uint32_t      * entries,
964                             bool_t        * done );
965 
966/*****************************************************************************************
967 * This function  updates the FS on the IOC device for a given inode identified by
968 * the <inode> argument. It scan all pages registered in the associated mapper,
969 * and copies from mapper to device each page marked as dirty.
970 * WARNING : The target <inode> cannot be a directory, because all modifications in a
971 * directory are synchronously done on the IOC device by the two vfs_fs_add_dentry()
972 * and vfs_fs_remove_dentry() functions.
973 *
974 * Depending on the file system type, it calls the relevant, FS specific function.
975 * It must be called by a thread running in the inode cluster.
976 *****************************************************************************************
977 * @ inode   : local pointer on inode.
978 * @ return 0 if success / return EIO if failure during device access.
979 ****************************************************************************************/
980error_t vfs_fs_sync_inode( struct vfs_inode_s * inode );
981
982/*****************************************************************************************
983 * This function updates the FS defined by the <fs_type> argument on the IOC device
984 * for the FAT itself. It scan all clusters registered in the FAT mapper, and copies
985 * to device each page marked as dirty.
986 *
987 * Depending on the file system type, it calls the relevant, FS specific function.
988 * It can be called by a thread running in any cluster.
989 *****************************************************************************************
990 * @ fs_type   : specific file system type.
991 * @ return 0 if success / return EIO if failure during device access.
992 ****************************************************************************************/
993error_t vfs_fs_sync_fat( vfs_fs_type_t fs_type );
994
995/*****************************************************************************************
996 * This function updates the free clusters info on the IOC device for the FS defined
997 * by the <fs_type> argument.
998 *
999 * Depending on the file system type, it calls the relevant, FS specific function.
1000 * It can be called by a thread running in any cluster.
1001 *****************************************************************************************
1002 * @ fs_type   : specific file system type.
1003 * @ return 0 if success / return EIO if failure during device access.
1004 ****************************************************************************************/
1005error_t vfs_fs_sync_free_info( vfs_fs_type_t fs_type );
1006
1007/******************************************************************************************
1008 * This function allocates a free cluster from the FS identified by the <fs_type>
1009 * argument. It updates the selected FS File Allocation Table.
1010 *
1011 * Depending on the file system type, it calls the relevant, FS specific function.
1012 * It can be called by a thread running in any cluster.
1013 ******************************************************************************************
1014 * @ fs_type   : [in]  File System type.
1015 * @ cluster   : [out] cluster index in File system.
1016 * @ return 0 if success / return -1 if no free cluster
1017 *****************************************************************************************/
1018error_t vfs_fs_cluster_alloc( uint32_t   fs_type,
1019                              uint32_t * cluster );
1020
1021/******************************************************************************************
1022 * This function makes all I/O operations required to release all clusters allocated
1023 * on IOC device to a given inode, identified by the <inode_xp> argument.
1024 * Depending on the file system type, it calls the proper, FS specific function.
1025 * It is called by the vfs_unlink() function.
1026 * It can be executed by a thread running in any cluster.
1027 * This function does NOT take any lock.
1028 ******************************************************************************************
1029 * @ inode_xp  : extended pointer on inode.
1030 * @ return 0 if success / return -1 if device access failure.
1031 *****************************************************************************************/
1032error_t vfs_fs_release_inode( xptr_t  inode_xp ); 
1033
1034/******************************************************************************************
1035 * This function makes the I/O operation to move one page identified by the <page_xp>
1036 * argument to/from the IOC device from/to the mapper, as defined by <to_mapper>.
1037 * Depending on the file system type, it calls the proper, FS specific function.
1038 * It is used in case of MISS on the mapper, or when a dirty page in the mapper must
1039 * be updated in the File System.
1040 * The mapper pointer is obtained from the page descriptor.
1041 * It can be executed by any thread running in any cluster.
1042 * This function does NOT take any lock.
1043 ******************************************************************************************
1044 * @ page_xp   : extended pointer on the page descriptor.
1045 * @ to_mapper : transfer direction.
1046 * @ returns 0 if success / return -1 if device access failure.
1047 *****************************************************************************************/
1048error_t vfs_fs_move_page( xptr_t  page_xp,
1049                          bool_t  to_mapper );
1050
1051
1052#endif  /* _VFS_H_ */
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