source: trunk/kernel/fs/vfs.h @ 614

Last change on this file since 614 was 614, checked in by alain, 3 years ago

1) introduce a dev_ioc_sync_write() function in IOC API,

to improve the DEVFS synchronous update.

2) fix a big bug in both the user_dir_create() and user_dir_destroy()

functions: add an extended pointer on the reference client process
in the function's arguments.

File size: 59.4 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#include <dev_ioc.h>
44
45/****  Forward declarations  ***/
46
47struct vfs_inode_s;
48struct vfs_dentry_s;
49struct vfs_ctx_s;
50struct vfs_file_s;
51
52struct mapper_s;
53struct process_s;
54struct device_s;
55struct vseg_s;
56struct page_s;
57
58/******************************************************************************************
59 * These flags are used to define the working mode of the vfs_lookup() function. 
60 *****************************************************************************************/
61
62#define VFS_LOOKUP_DIR      0x01     /* the searched inode must be a directory           */
63#define VFS_LOOKUP_OPEN         0x02     /* the search is for an open/opendir                */
64#define VFS_LOOKUP_PARENT       0x04     /* return the parent inode (not the inode itself)   */
65#define VFS_LOOKUP_CREATE   0x10     /* file must be created if missing                  */
66#define VFS_LOOKUP_EXCL     0x20     /* file cannot previously exist                     */
67
68/******************************************************************************************
69 * This structure defines a VFS context, that contains informations common to all inodes
70 * and dentries for a given file system. As it is declared as a global variable in the
71 * kdata segment (fs_context[] array), it is replicated in all clusters.
72 * The <extend> field is a pointer on the FS specific context extension.
73 * This extension is dynamically allocated by kernel_init in all clusters.
74 * In each cluster, both this VFS context and the FS specific context are handled as
75 * private by the local OS intance.
76 *****************************************************************************************/
77
78typedef enum
79{
80        FS_TYPE_DEVFS = 0,
81        FS_TYPE_FATFS = 1,
82        FS_TYPE_RAMFS = 2,
83 
84        FS_TYPES_NR   = 3,
85}
86vfs_fs_type_t;
87
88typedef enum
89{
90    CTX_ATTR_READ_ONLY    = 0x01,            /*! write access prohibited                 */
91    CTX_ATTR_SYNC         = 0x10,            /*! synchronise FS on each write            */
92}
93vfs_ctx_attr_t;
94
95typedef struct vfs_ctx_s
96{
97        vfs_fs_type_t  type;                     /*! File System type                        */
98        uint32_t           attr;                     /*! global attributes for all files in FS   */
99        uint32_t       total_clusters;           /*! total number of clusters on device      */
100        uint32_t       cluster_size;             /*! cluster size on device (bytes)          */
101        xptr_t         vfs_root_xp;              /*! extended pointer on VFS root inode      */
102    busylock_t     lock;                     /*! lock protecting inum allocator          */
103    uint32_t       bitmap[BITMAP_SIZE(CONFIG_VFS_MAX_INODES)];  /* inum allocator        */
104    void         * extend;                   /*! FS specific context extension           */
105}
106vfs_ctx_t;
107
108/******************************************************************************************
109 * This structure define a VFS inode.
110 * An inode has several children dentries (if it is a directory), an can have several
111 * parents dentries (if it hass several aliases links):
112 * - The "parents" field is the root of the xlist of parents dentries, and the "links"
113 *   fiels define the number of aliases parent dentries. only a FILE inode can have
114 *   several parents (no hard links for directories).
115 * - The "children" field is an embedded xhtab containing pointers on all local children
116 *   dentries. This set of children is empty for a FILE inode.
117 * Synchronisation:
118 * - the main_lock (remote_rwlock) is used during the inode tree traversal,
119 *   or for inode modification (add/remove children in xhtab).
120 * - the size_lock (remote_rwlock) is used during read/write accesses to the size
121 *   field in the mapper.
122 * - access to the data stored in the associated mapper use the mapper remote_rwlock
123 *   protecting radix tree traversal and modifications.
124 *****************************************************************************************/
125
126/* this enum define the VFS inode types values                                           */
127/* WARNING : this enum must be kept consistent with macros in <shared_stat.h> file       */
128/*           and with types in <shared_dirent.h> file.                                   */
129
130typedef enum   
131{
132    INODE_TYPE_FILE  =     0,           /*! regular file                                 */
133    INODE_TYPE_DIR   =     1,           /*! directory                                    */
134    INODE_TYPE_FIFO  =     2,           /*! POSIX named pipe                             */
135    INODE_TYPE_PIPE  =     3,           /*! POSIX anonymous pipe                         */
136    INODE_TYPE_SOCK  =     4,           /*! POSIX socket                                 */
137    INODE_TYPE_DEV   =     5,           /*! character device                             */
138    INODE_TYPE_BLK   =     6,           /*! block device                                 */
139    INODE_TYPE_SYML  =     7,           /*! symbolic link                                */
140}
141vfs_inode_type_t;
142
143/* this enum define the VFS inode attributes values */
144
145typedef enum 
146{
147    INODE_ATTR_DIRTY   =     0x01,       /* modified versus the value on device          */ 
148    INODE_ATTR_INLOAD  =     0x04,       /* loading from device in progress              */
149    INODE_ATTR_NEW     =     0x08,       /* not saved on device yet                      */
150}
151vfs_inode_attr_t;
152
153typedef struct vfs_inode_s
154{
155        struct vfs_ctx_s * ctx;              /*! local pointer on FS context                 */
156        uint32_t           inum;             /*! inode identifier (unique in file system)    */
157        uint32_t           attr;             /*! inode attributes (see above)                */
158        vfs_inode_type_t   type;             /*! inode type (see above)                      */
159        uint32_t           size;             /*! number of bytes                             */
160        uint32_t           uid;              /*! user owner identifier                       */
161        uint32_t           gid;              /*! group owner identifier                      */
162    uint32_t           rights;           /*! access rights                               */
163        xlist_entry_t      parents;          /*! root of list of parents dentries            */
164        uint32_t           links;            /*! number of parent dentries (hard links)      */
165        xhtab_t            children;         /*! embedded xhtab of children dentries         */
166        remote_rwlock_t    size_lock;        /*! protect read/write to size                  */
167        remote_rwlock_t    main_lock;        /*! protect inode tree traversal and modifs     */
168//  list_entry_t       list;             /*! member of set of inodes in same cluster     */
169//  list_entry_t       wait_root;        /*! root of threads waiting on this inode       */
170        struct mapper_s  * mapper;           /*! associated file cache                       */
171        void             * extend;           /*! fs_type_specific inode extension            */
172}
173vfs_inode_t;
174
175/* This define the masks for the inode <rights> field  */
176
177#define VFS_ISUID          0x0004000
178#define VFS_ISGID          0x0002000
179#define VFS_ISVTX          0x0001000
180
181#define VFS_IRWXU      0x0000700
182#define VFS_IRUSR      0x0000400
183#define VFS_IWUSR      0x0000200
184#define VFS_IXUSR      0x0000100
185
186#define VFS_IRWXG      0x0000070
187#define VFS_IRGRP      0x0000040
188#define VFS_IWGRP      0x0000020
189#define VFS_IXGRP      0x0000010
190
191#define VFS_IRWXO      0x0000007
192#define VFS_IROTH      0x0000004
193#define VFS_IWOTH      0x0000002
194#define VFS_IXOTH      0x0000001
195
196/******************************************************************************************
197 * This structure defines a directory entry.
198 * A dentry contains the name of a remote file/dir, an extended pointer on the
199 * inode representing this file/dir, a local pointer on the inode representing
200 * the parent directory.
201 * A dentry can be member of the set of children of a given directory inode (xhtab).
202 * A dentry can be member of the set of parents  of a given inode (xlist).
203 *****************************************************************************************/
204
205typedef struct vfs_dentry_s
206{
207    struct vfs_ctx_s   * ctx;            /*! local pointer on FS context                 */
208        char                 name[CONFIG_VFS_MAX_NAME_LENGTH];
209        uint32_t             length;         /*! name length (bytes)                         */
210    struct vfs_inode_s * parent;         /*! local pointer on parent inode               */
211    xptr_t               child_xp;       /*! extended pointer on child inode             */
212    xlist_entry_t        children;       /*! member of set of children dentries          */
213    xlist_entry_t        parents;        /*! member of set of parent dentries            */
214        void               * extend;         /*! FS specific extension                       */
215}
216vfs_dentry_t;
217
218/******************************************************************************************
219 * This file structure describes an open file/directory for a given process.
220 * It is not replicated, and is dynamically allocated in the cluster that contains
221 * the inode, when a thread makes an open() or opendir() system call.
222 * It cannot exist a file structure without an inode structure in same cluster.
223 * As the fd_array (containing extended pointers on the open file descriptors)
224 * is replicated in all process descriptors, we need a references counter.
225 *****************************************************************************************/
226
227typedef enum
228{
229    FD_ATTR_READ_ENABLE    = 0x01,     /*! read access possible                         */
230    FD_ATTR_WRITE_ENABLE   = 0x02,     /*! write access possible                        */
231    FD_ATTR_APPEND         = 0x04,     /*! append on each write                         */
232    FD_ATTR_CLOSE_EXEC     = 0x08,     /*! close file on exec                           */
233    FD_ATTR_SYNC           = 0x10,     /*! synchronise FS on each write                 */
234    FD_ATTR_IS_DIR         = 0x20,     /*! this is a directory                          */
235}
236vfs_file_attr_t;
237
238typedef struct vfs_file_s
239{
240        struct vfs_ctx_s      * ctx;        /*! local pointer on FS context.                 */
241        uint32_t                gc;         /*! generation counter                           */
242        vfs_file_attr_t         attr;       /*! file attributes bit vector (see above)       */
243        vfs_inode_type_t        type;       /*! same type as inode                           */
244        uint32_t                offset;     /*! seek position in file                        */
245        uint32_t                refcount;   /*! all pointers on this file descriptor         */
246        remote_rwlock_t         lock;       /*! protect offset modifications                 */
247        struct mapper_s       * mapper;     /*! associated file cache                        */
248        struct vfs_inode_s    * inode;      /*! local pointer on associated inode            */
249        void                  * extend;     /*! FS specific extension                        */
250}
251vfs_file_t;
252
253
254/******************************************************************************************
255 *        These functions access / modify  a VFS context.
256 *****************************************************************************************/
257
258/******************************************************************************************
259 * This function initialise a (statically allocated) VFS context in local cluster.
260 ******************************************************************************************
261 * @ fs_type        : file system type.
262 * @ attr           : global attributes (for all files in FS.
263 * @ total_clusters : total number of clusters on device.
264 * @ cluster_size   : cluster size on device (bytes).
265 * @ vfs_root_xp    : extended pointer on VFS root inode.
266 * @ extend         : fs_type_specific extension.
267 *****************************************************************************************/
268void vfs_ctx_init( vfs_fs_type_t   type,
269                   uint32_t        attr,
270                       uint32_t        total_clusters,
271                       uint32_t        cluster_size,
272                       xptr_t          vfs_root_xp,
273                   void          * extend );
274
275/******************************************************************************************
276 * This function allocates an inode identifier from the local cluster inum allocator.
277 * The inum respects a fixed format:
278 * - the 16 MSB bits contain the cluster identifier : cxy
279 * - the 16 LSB bits contains the local inode identifier  : lid
280 ******************************************************************************************
281 * @ ctx      : local pointer on file system context.
282 * @ inum     : [ou] buffer for allocated inode identifier.
283 * @ return 0 if success / return non-zero if error.
284 *****************************************************************************************/
285error_t vfs_ctx_inum_alloc( vfs_ctx_t * ctx,
286                            uint32_t  * inum );
287
288/******************************************************************************************
289 * This function release an inode identifier.                                 
290 ******************************************************************************************
291 * @ ctx      : local pointer on file system context.
292 * @ inum     : released inode identifier.
293 *****************************************************************************************/
294void vfs_ctx_inum_release( vfs_ctx_t * ctx,
295                           uint32_t    inum );
296
297
298
299/******************************************************************************************
300 *        These low-level functions access / modify a VFS inode descriptor
301 *****************************************************************************************/
302
303/******************************************************************************************
304 * This function returns a printable string for the inode type.
305 *****************************************************************************************/
306const char * vfs_inode_type_str( vfs_inode_type_t type );
307
308/******************************************************************************************
309 * This function allocates memory from local cluster for an inode descriptor and the
310 * associated mapper. It initialise these descriptors from arguments values.
311 * It must called by a local thread. Use the RPC_INODE_CREATE if client thread is remote.
312 ******************************************************************************************
313 * @ fs_type    : file system type.
314 * @ inode_type : inode type.
315 * @ attr       : inode attributes.
316 * @ rights     : inode access rights.
317 * @ uid        : user owner ID.
318 * @ gid        : group owner ID.
319 * @ inode_xp   : [out] buffer for extended pointer on created inode.
320 * @ return 0 if success / return ENOMEM or EINVAL if error.
321 *****************************************************************************************/
322error_t vfs_inode_create( vfs_fs_type_t     fs_type,
323                          vfs_inode_type_t  inode_type,
324                          uint32_t          attr,
325                          uint32_t          rights,
326                          uid_t             uid,
327                          gid_t             gid,
328                          xptr_t          * inode_xp );
329
330/******************************************************************************************
331 * This function releases memory allocated to an inode descriptor, including
332 * all memory allocated to the mapper (both mapper descriptor and radix tree).
333 * The mapper should not contain any dirty page (should be synchronized before deletion).
334 * It must be executed by a thread running in the cluster containing the inode.
335 * Use the rpc_vfs_inode_destroy_client() function if required.
336 ******************************************************************************************
337 * @ inode  : local pointer on inode descriptor.
338 *****************************************************************************************/
339void vfs_inode_destroy( vfs_inode_t *  inode ); 
340
341/******************************************************************************************
342 * This function returns the <size> of a file/dir from a remote inode,
343 * taking the remote_rwlock protecting <size> in READ_MODE.
344 *****************************************************************************************
345 * @ inode_xp  : extended pointer on the remote inode.
346 * @ return the current size.
347 *****************************************************************************************/
348uint32_t vfs_inode_get_size( xptr_t inode_xp );
349
350/******************************************************************************************
351 * This function set the <size> of a file/dir to a remote inode,
352 * taking the remote_rwlock protecting <size> in WRITE_MODE.
353 *****************************************************************************************
354 * @ inode_xp  : extended pointer on the remote inode.
355 * @ size      : value to be written.
356 *****************************************************************************************/
357void vfs_inode_set_size( xptr_t   inode_xp,
358                         uint32_t size );
359
360/******************************************************************************************
361 * This function takes the main lock of a remote inode.
362 * This lock protect all inode fields, including the children dentries.
363 *****************************************************************************************
364 * @ inode_xp  : extended pointer on the remote inode.
365 *****************************************************************************************/
366void vfs_inode_lock( xptr_t inode_xp );
367
368/******************************************************************************************
369 * This function releases the main lock of a remote inode.
370 * This lock protect all inode fiels, including the children dentries.
371 *****************************************************************************************
372 * @ inode_xp  : extended pointer on the remote inode.
373 *****************************************************************************************/
374void vfs_inode_unlock( xptr_t inode_xp );
375
376/******************************************************************************************
377 * This debug function copies the name of a remote inode identified by the <inode_xp>
378 * argument to a local buffer identified by the <name> argument.
379 * The local buffer size must be at least CONFIG_VFS_MAX_NAME_LENGTH.
380 *****************************************************************************************
381 * @ inode_xp  : extended pointer on the remote inode.
382 * @ name      : local buffer pointer.
383 *****************************************************************************************/
384void vfs_inode_get_name( xptr_t inode_xp,
385                         char * name );
386
387/******************************************************************************************
388 * This function accesses successively all pages of a file identified by the <inode>,
389 * argument, to force misses, and load all pages into mapper.
390 * The target inode can be a directory or a file, but this function is mainly used
391 * to prefetch a complete directory to the mapper.
392 * It must be executed by a thread running in the cluster containing the inode.
393 * This function does NOT take any lock.
394 ******************************************************************************************
395 * @ inode  : local pointer on inode.
396 * @ return 0 if success / return -1 if device access failure.
397 *****************************************************************************************/
398error_t vfs_inode_load_all_pages( vfs_inode_t * inode );
399
400
401
402/******************************************************************************************
403 *        These low-level functions access / modify a VFS dentry descriptor
404 *****************************************************************************************/
405
406/******************************************************************************************
407 * This function allocates memory from local cluster for a dentry descriptor,
408 * initialises it from  arguments values, and returns the extended pointer on dentry.
409 * It must called by a local thread. Use the RPC_DENTRY_CREATE if client thread is remote.
410 ******************************************************************************************
411 * @ fs_type    : [in]  file system type.
412 * @ name       : [in]  directory entry file/dir name.
413 * @ dentry_xp  : [out] buffer for extended pointer on created dentry.
414 * @ return 0 if success / return ENOMEM or EINVAL if error.
415 *****************************************************************************************/
416error_t vfs_dentry_create( vfs_fs_type_t   fs_type,
417                           char          * name,
418                           xptr_t        * dentry_xp );
419 
420/******************************************************************************************
421 * This function removes the dentry from the parent inode xhtab, and releases the memory
422 * allocated to the dentry descriptor.
423 * It must be executed by a thread running in the cluster containing the dentry.
424 * Use the RPC_DENTRY_DESTROY if required.
425 ******************************************************************************************
426 * @ dentry  : [in] local pointer on dentry descriptor.
427 *****************************************************************************************/
428void vfs_dentry_destroy( vfs_dentry_t *  dentry ); 
429
430
431/******************************************************************************************
432 *        These low-level functions access / modify a VFS file descriptor
433 *****************************************************************************************/
434
435/******************************************************************************************
436 * This function allocates memory and initializes a new local file descriptor.
437 * It must be executed in the cluster containing the inode.
438 * If the client thread is not running in the owner cluster, it must use the
439 * rpc_vfs_file_create_client() function.
440 ******************************************************************************************
441 * @ inode    : local pointer on associated inode.
442 * @ attr     : file descriptor attributes.
443 * @ file_xp  : [out] buffer for extended pointer on created file descriptor.
444 * @ return 0 if success / return ENOMEM if error.
445 *****************************************************************************************/
446error_t vfs_file_create( vfs_inode_t * inode,
447                         uint32_t      attr,
448                         xptr_t      * file_xp ); 
449
450/******************************************************************************************
451 * This function releases memory allocated to a local file descriptor.
452 * It must be executed by a thread running in the cluster containing the inode,
453 * and the file refcount must be zero.
454 * If the client thread is not running in the owner cluster, it must use the
455 * rpc_vfs_file_destroy_client() function.
456 ******************************************************************************************
457 * @ file  : local pointer on file descriptor.
458 *****************************************************************************************/
459void vfs_file_destroy( vfs_file_t *  file ); 
460
461/******************************************************************************************
462 * These functions increment (resp. decrement) the count field in a remote file
463 * descriptor, using a remote_atomic access.
464 *****************************************************************************************/
465void vfs_file_count_up  ( xptr_t   file_xp );
466void vfs_file_count_down( xptr_t   file_xp );
467
468
469
470
471/******************************************************************************************
472 *        These functions access / modify the distributed VFS Inode Tree
473 *****************************************************************************************/
474
475/******************************************************************************************
476 * This function returns in a kernel <buffer> allocated by the caller function,
477 * the pathname of a file/dir identified by the <inode_xp> argument.
478 * It traverse the Inode Tree from the target node to the root.
479 * It can be called by any thread running in any cluster.
480 * As this buffer if filled in "reverse order" (i.e. from the target inode to the root),
481 * the pathname is stored in the higher part of the buffer.
482 * A pointer on the first character of the pathname is returned in <first> buffer.
483 *
484 * WARNING : This function takes & releases the remote_rwlock protecting the Inode Tree.
485 ******************************************************************************************
486 * @ inode_xp    : [in]  extended pointer on target inode descriptor.
487 * @ buffer      : [in]  kernel buffer for pathname (allocated by caller).
488 * @ first       : [out] pointer on first character in buffer.
489 * @ max_size    : [in]  max number of characters in buffer.
490 * @ return 0 if success / return EINVAL if buffer too small.
491 *****************************************************************************************/
492error_t vfs_get_path( xptr_t    inode_xp,
493                      char    * buffer,
494                      char   ** first,
495                      uint32_t  max_size );
496
497/******************************************************************************************
498 * This function traverses the the Inode Tree, from inode identified by the <root_xp>
499 * argument, and returns in <inode_xp> the inode identified by the < pathname> argument.
500 * It can be called by a thread running in any cluster.
501 * It supports the following flags that define the lookup modes :
502 * - VFS_LOOKUP_DIR    : the searched inode must be a directory
503 * - VFS_LOOKUP_OPEN   : the search is for an open/opendir
504 * - VFS_LOOKUP_PARENT : return the parent inode (not the inode itself)
505 * - VFS_LOOKUP_CREATE : file/directory must be created if missing on IOC
506 * - VFS_LOOKUP_EXCL   : file cannot previously exist
507 * As the inode Tree is a cache, the search policy is the following :
508 * - If a given directory name in the path is not found in the inode tree, it try to load
509 *   the missing dentry/inode couple, from informations found in the parent directory.
510 * - If this directory entry does not exist on IOC, it returns an error.
511 * - If the the file identified by the pathname does not exist on IOC but the
512 *   flag CREATE is set, the inode is created. It returns an error otherwise.
513 * - If the the file identified by the pathname exist on device, but both flags EXCL
514 *   and CREATE are set, an error is returned.
515 * - If the PARENT flag is set, it returns in <inode_xp> an extended pointer on the parent
516 *   inode, and copies in <last_name> buffer a string containing the last name in path.
517 *
518 * WARNING : The remote_rwlock protecting the Inode Tree must be taken by the caller.
519 *
520 * TODO the access rights are not checked yet.
521 ******************************************************************************************
522 * @ root_xp     : [in]  extended pointer on root inode (can be root of a subtree).
523 * @ pathname    : [in]  path (can be relative or absolute).
524 * @ lookup_mode : [in]  flags defining the searching mode.
525 * @ inode_xp    : [out] buffer for extended pointer on searched inode.
526 * @ last_name   : [out] pointer on buffer for last name in path.
527 * @ return 0 if success / ENOENT if inode not found , EACCES if permisson denied,
528 *****************************************************************************************/
529error_t vfs_lookup( xptr_t             root_xp,
530                    char             * pathname,
531                    uint32_t           lookup_mode,
532                                        xptr_t           * inode_xp,
533                    char             * last_name );
534
535/******************************************************************************************
536 * This function creates a new couple dentry/inode, and insert it in the Inode-Tree.
537 * Only the distributed Inode Tree is modified: it does NOT modify the parent mapper,
538 * and does NOT update the FS on IOC device.
539 * It can be executed by any thread running in any cluster (can be different from both
540 * the child cluster and the parent cluster).
541 *
542 * [Implementation]
543 * As there are cross-references between inode and dentry, this function implements
544 * a three steps scenario :
545 * 1) The dentry descriptor is created in the cluster containing the existing <parent_xp>
546 *    inode, and partially initialized, using the RPC_VFS_CREATE DENTRY if required.
547 * 2) The inode and its associated mapper are created in cluster identified by <child_cxy>,
548 *    and partially initialised, using the RPC_VFS_CREATE_INODE if required.
549 *    The new inode and the parent inode can have different FS types.
550 * 3) The pointers between the parent inode, the new dentry, and the child inode
551 *    are updated, using remote accesses.
552 ******************************************************************************************
553 * @ child_inode_cxy  : [in]  target cluster for child inode.
554 * @ child_inode_type : [in]  child inode type
555 * @ fs_type          : [in]  child inode FS type.
556 * @ parent_inode_xp  : [in]  extended pointer on parent inode.
557 * @ name             : [in]  new directory entry name.
558 * @ dentry_xp        : [out] buffer for extended pointer on dentry
559 * @ child_inode_xp   : [out] buffer for extended pointer on child inode.
560 * @ return 0 if success / -1 if dentry or inode cannot be created.
561 *****************************************************************************************/
562error_t vfs_add_child_in_parent( cxy_t              child_inode_cxy,
563                                 vfs_inode_type_t   child_inode_type,
564                                 vfs_fs_type_t      fs_type,
565                                 xptr_t             parent_inode_xp,
566                                 char             * name,
567                                 xptr_t           * dentry_xp,   
568                                 xptr_t           * child_inode_xp );
569
570/******************************************************************************************
571 * This function removes a remote dentry from the Inode-Tree.
572 * - It removes the dentry from the parent inode xhtab ("children" field), and from the
573 *   child inode xlist ("parents" field).
574 * - It releases the memory allocated to the dentry descriptor.
575 * - If the number of parents of the child inode is one, it also releases the memory
576 *   allocated to the child inode.
577 * Only the Inode Tree is modified: it does NOT modify the parent mapper,
578 * and does NOT update the FS on IOC device.
579 * It can be executed by any thread running in any cluster (can be different from both
580 * the inode cluster and the dentry cluster).
581 ******************************************************************************************
582 * @ dentry_xp   : extended pointer on removed dentry.
583 *****************************************************************************************/
584void vfs_remove_child_from_parent( xptr_t dentry_xp );
585
586/******************************************************************************************
587 * This function is called by the vfs_lookup() function when a new dentry/inode must
588 * be created from scratch and introduced in both the Inode Tree and the IOC device.
589 * The dentry and inode descriptors have been created by the caller:
590 * - It allocates one cluster from the relevant FS, and updates the File Allocation
591 *   Table (both the FAT mapper, and the IOC device).
592 * - It set the "size", and "extend" fields in child inode descriptor.
593 * - It updates the parent directory to introduce the new child in the parent directory
594 *   inode descriptor (radix tree), in theparent inode mapper, and on IOC device.
595 * - It set the "extend" field in dentry descriptor.
596 * It can be called by a thread running in any cluster.
597 ******************************************************************************************
598 * @ parent_xp   : extended pointer on parent inode descriptor.
599 * @ dentry_xp   : extended pointer on new dentry descriptor.
600 * @ child_xp    : extended pointer on child inode descriptor.
601 * @ return 0 if success / -1 if failure.
602 *****************************************************************************************/
603error_t vfs_new_dentry_init( xptr_t   parent_xp,
604                             xptr_t   dentry_xp,
605                             xptr_t   child_xp );
606
607/******************************************************************************************
608 * This function creates in the directory identified by the <child_xp> argument,
609 * the two special dentries <.> and <..>. The parent directory inode is defined
610 * by the <parent_xp> argument. The two dentries are introduced in the Inode Tree.
611 * They are also introduced in the child directory mapper, and the IOC device is updated.
612 * This function is called by all functions creating a brand new directory : vfs_mkdir(),
613 * devfs_global_init(), and devfs_local_init().
614 ******************************************************************************************
615 * @ child_xp    : extended pointer on new directory inode.
616 * @ parent_xp   : extended pointer on parent directory inode.
617 * @ return 0 if success / -1 if failure.
618 *****************************************************************************************/
619error_t vfs_add_special_dentries( xptr_t  child_xp,
620                                  xptr_t  parent_xp );
621
622/******************************************************************************************
623 * This recursive function diplays a complete inode/dentry sub-tree.
624 * Any inode can be selected as the sub-tree root.
625 * WARNING : this function is not protected against a concurrent inode/dentry removal...
626 ******************************************************************************************
627 * @ inode_xp   : extended pointer on sub-tree root inode.
628 *****************************************************************************************/
629void vfs_display( xptr_t   inode_xp );
630
631/******************************************************************************************
632 * This function mount a given file system type for a given process
633 * TODO non implemented yet [AG].     
634 *****************************************************************************************/
635error_t vfs_mount_fs_root( struct device_s  * device,
636                                       uint32_t           fs_type,
637                                       struct process_s * process );
638
639
640
641
642/******************************************************************************************
643 *        These functions define the VFS "syscalls" API (user commands)
644 *****************************************************************************************/
645
646/******************************************************************************************
647 * This function moves <size> bytes between a remote file mapper, identified by the
648 * <file_xp> argument, and a - possibly distributed - user space <buffer>, taken into
649 * account the offset in <file_xp>. The transfer direction is defined by <to_buffer>.
650 * It is called by the sys_read() and sys_write() functions.
651 ******************************************************************************************
652 * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false.
653 * @ file_xp   : extended pointer on the remote file descriptor.
654 * @ buffer    : user space pointer on buffer (can be physically distributed).
655 * @ size      : requested number of bytes from offset.
656 * @ returns number of bytes actually moved if success / -1 if error.
657 *****************************************************************************************/
658int vfs_user_move( bool_t   to_buffer,
659                   xptr_t   file_xp, 
660                   void   * buffer,
661                   uint32_t size );
662
663/******************************************************************************************
664 * This function moves <size> bytes between a remote file mapper, identified by the
665 * <file_xp> argument, and a - possibly remote - kernel <buffer_xp>, taken into
666 * account the offset in <file_xp>. The transfer direction is defined by <to_buffer>.
667 * It is called by the elf_load_process() function.
668 ******************************************************************************************
669 * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false.
670 * @ file_xp   : extended pointer on the remote file descriptor.
671 * @ buffer_xp : user space pointer on buffer (can be physically distributed).
672 * @ size      : requested number of bytes from offset.
673 * @ returns 0 if success / -1 if error.
674 *****************************************************************************************/
675error_t vfs_kernel_move( bool_t   to_buffer,
676                         xptr_t   file_xp, 
677                         xptr_t   buffer_xp,
678                         uint32_t size );
679
680/******************************************************************************************
681 * This function allocates a vfs_file_t structure in the cluster containing the inode
682 * identified by the <root_xp> & <path> arguments.
683 * It initializes it, register it in the reference process fd_array identified by the
684 * <process_xp> argument, and returns both the extended pointer on the file descriptor,
685 * and the allocated index in the <file_xp> and <file_id> buffers.
686 * The pathname can be relative to current directory or absolute.
687 * If the inode does not exist in the inode cache, it try to find the file on the IOC
688 * device, and creates an inode on a pseudo randomly selected cluster if found.
689 * It the requested file does not exist on device, it creates a new inode if the
690 * O_CREAT flag is set, and return an error otherwise.
691 *
692 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
693 ******************************************************************************************
694 * @ root_xp     : extended pointer on path root inode.
695 * @ path        : file pathname (absolute or relative to current directory).
696 * @ process_xp  : extended pointer on client reference process.
697 * @ flags       : defined in vfs_file_t structure.
698 * @ mode        : access rights (as defined by chmod).
699 * @ file_xp     : [out] buffer for extended pointer on created remote file descriptor.
700 * @ file_id     : [out] buffer for created file descriptor index in reference fd_array.
701 * @ return 0 if success / return non-zero if error.
702 *****************************************************************************************/
703error_t vfs_open( xptr_t             root_xp,
704                          char             * path,
705                  xptr_t             process_xp,
706                          uint32_t           flags,
707                  uint32_t           mode,
708                          xptr_t           * file_xp,
709                          uint32_t         * file_id );
710
711/******************************************************************************************
712 * This function set a new value in the offset of the open file descriptor <file_xp>.
713 * This value depends on the <whence> argument:
714 * - if VFS_SEEK_SET, new value is <offset>
715 * - if VFS_SEEK_CUR, new value is current_offset + <offset>
716 * - if VFS_SEEK_END, new value is file_size + <offset>
717 ******************************************************************************************
718 * @ file_xp   : extended pointer on the remote open file descriptor.
719 * @ offset    : local pointer on source kernel buffer.
720 * @ whence    : VFS_SEEK_SET / VFS_SEEK_CUR / VFS_SEEK_END.
721 * @ new_offset : [out] buffer for new offset value.
722 * @ returns 0 if success / -1 if error.
723 *****************************************************************************************/
724error_t vfs_lseek( xptr_t     file_xp,
725                   uint32_t   offset,
726                   uint32_t   whence, 
727                   uint32_t * new_offset );
728
729/******************************************************************************************
730 * This function close the - non-replicated - file descriptor identified by the <file_xp>
731 * and <file_id> arguments.
732 * 1) All entries in the fd_array copies are directly reset by the calling thread,
733 *    using remote accesses.
734 * 2) The memory allocated to file descriptor in cluster containing the inode is released.
735 *    It requires a RPC if cluster containing the file descriptor is remote.
736 ******************************************************************************************
737 * @ file_xp     : extended pointer on the file descriptor in owner cluster.
738 * @ file_id     : file descriptor index in fd_array.
739 * @ returns 0 if success / -1 if error.
740 *****************************************************************************************/
741error_t vfs_close( xptr_t    file_xp,
742                   uint32_t  file_id );
743
744/******************************************************************************************
745 * This function is called by the kernel to create in the file system a new directory
746 * identified by the <root_xp> & <path> arguments, with the access permission defined
747 * by the <rights> argument. All nodes in the path - but the last -  must exist.
748 *
749 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
750 ******************************************************************************************
751 * @ root_xp : extended pointer on path root inode (any inode in Inode Tree).
752 * @ path    : pathname (absolute or relative to current directory).
753 * @ rights  : access rights.
754 * @ returns 0 if success / -1 if error.
755 *****************************************************************************************/
756error_t vfs_mkdir( xptr_t   root_xp,
757                   char   * path,
758                   uint32_t rights );
759
760/******************************************************************************************
761 * This function is called by the kernel to create in the file system a new directory
762 * entry identified by the <new_root_xp> & <new_path> arguments, to be linked to an
763 * existing inode, identified by the  <old_root_xp> & <old_path> arguments.
764 * If the link is successful, the link count of the target inode is incremented.
765 * The <new_path> and <old_path> share equal access rights to the underlying inode.
766 * Both the IOC device and the Inode Tree are modified.
767 $
768 * TODO This function should handle any type of node, but the current implementation
769 * handles only the FILE and DIR types.
770 *
771 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
772 ******************************************************************************************
773 * @ old_root_xp : extended pointer on old path root inode (any inode in Inode Tree).
774 * @ old_path    : old pathname (absolute or relative to current directory).
775 * @ nld_root_xp : extended pointer on new path root inode (any inode in Inode Tree).
776 * @ new_path    : new pathname (absolute or relative to current directory).
777 * @ returns 0 if success / -1 if error.
778 *****************************************************************************************/
779error_t vfs_link( xptr_t   old_root_xp,
780                  char   * old_path,
781                  xptr_t   new_root_xp,
782                  char   * new_path );
783
784/******************************************************************************************
785 * This function is called by the kernel to remove from the file system a directory entry
786 * identified by the  <root_xp> & <path> arguments.
787 * The link count of the target node is decremented.
788 * If the removed link is the last, the target inode is deleted.
789 * Both the IOC device and the Inode Tree are modified.
790 *
791 * TODO This function should handle any type of node, but the current implementation
792 * handles only only the FILE and DIR types.
793 *
794 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
795 ******************************************************************************************
796 * @ root_xp  : extended pointer on root inode (can be any inode in Inode Tree).
797 * @ path     : pathname (absolute or relative to current directory).
798 * @ returns 0 if success / -1 if error.
799 *****************************************************************************************/
800error_t vfs_unlink( xptr_t   root_xp,
801                    char   * path );
802
803/******************************************************************************************
804 * This function returns, in the structure pointed by the <st> pointer, various
805 * informations on the inode identified by the <root_inode_xp> and <patname> arguments.
806 *
807 * TODO : only partially implemented yet (only size and inum fields).
808 *
809 * WARNING : this function takes & releases the remote_rwlock protecting the Inode Tree.
810 ******************************************************************************************
811 * @ root_xp    : extended pointer on path root inode (any inode in Inode Tree)
812 * @ pathname   : pathname to target inode.
813 * @ st         : local pointer on the stat structure in kernel space.
814 * @ returns 0 if success / -1 if error.
815 *****************************************************************************************/
816error_t vfs_stat( xptr_t        root_xp,
817                  char        * pathname,
818                  struct stat * st );
819
820/******************************************************************************************
821 * This function  creates a new directory as defined by the <root_xp> & <path> arguments.
822 * TODO not implemented yet...
823 ******************************************************************************************
824 * @ root_xp  : extended pointer on the path root directory.
825 * @ path     : pathname (absolute or relative to CWD).                     
826 * @ mode     : access rights (as defined by chmod)
827 * @ returns 0 if success / -1 if error.
828 *****************************************************************************************/
829error_t vfs_mkdir( xptr_t     root_xp,
830                   char     * path,
831                   uint32_t   mode );
832
833/******************************************************************************************
834 * This function makes the directory identified by the <root_xp and <path> arguments
835 * to become the working directory for the calling process.
836 ******************************************************************************************
837 * @ root_xp  : extended pointer on the path root directory.
838 * @ path     : pathname (absolute or relative to CWD).
839 * return 0 if success / -1 if error.
840 *****************************************************************************************/
841error_t vfs_chdir( xptr_t   root_xp,
842                   char   * path );
843
844/******************************************************************************************
845 * This function change the access rigths for the file/directory identified by the
846 * <root_xp> and <path> arguments as defined by the <mode> argument value.
847 ******************************************************************************************
848 * @ root_xp  : extended pointer on the path root directory.
849 * @ path     : pathname (absolute or relative to CWD).
850 * @ mode     : access rights
851 * return 0 if success / -1 if error.
852 *****************************************************************************************/
853error_t vfs_chmod( xptr_t        root_xp,
854                   char        * path,
855                   uint32_t      mode );
856
857/******************************************************************************************
858 * This function creates a named FIFO file.
859 * TODO not implemented yet                                                         
860 ******************************************************************************************
861 * @ root_xp  : extended pointer on the path root directory.
862 * @ path     : pathname (absolute or relative to CWD).
863 * @ mode     : access rights new value.
864 *****************************************************************************************/
865error_t vfs_mkfifo( xptr_t       root_xp,
866                    char       * path,
867                    uint32_t     mode );
868
869
870
871
872
873/******************************************************************************************
874 *        These functions define the VFS "FS" API to a specific File System
875 *****************************************************************************************/
876
877/******************************************************************************************
878 * This function makes the I/O operation to move one page identified by the <page_xp>
879 * argument to/from the IOC device from/to the mapper, as defined by <cmd_type>.
880 * Depending on the file system type, it calls the proper, FS specific function.
881 * It is used in case of MISS on the mapper, or when a dirty page in the mapper must
882 * be updated in the File System.
883 * The mapper pointer is obtained from the page descriptor.
884 * It can be executed by any thread running in any cluster.
885 * This function does NOT take any lock.
886 ******************************************************************************************
887 * @ page_xp   : extended pointer on page descriptor (for mapper and page_id).
888 * @ cmd_type  : IOC_READ / IOC_WRITE / IOC_SYNC_READ / IOC_SYNC_WRITE
889 * @ returns 0 if success / return -1 if device access failure.
890 *****************************************************************************************/
891error_t vfs_fs_move_page( xptr_t      page_xp,
892                          cmd_type_t  cmd_type );
893
894/******************************************************************************************
895 * This function updates the mapper associated to a directory inode identified by the
896 * <parent> argument, to add a new entry identified by the <dentry> argument.
897 * The directory inode descriptor and the dentry descriptor are in the same cluster.
898 * Depending on the file system type, it calls the proper, FS specific function.
899 * It also updates the dentry descriptor and/or the inode descriptor extensions
900 * as required by the specific file system type.
901 * Finally, it synchronously updates the parent directory on IOC device.
902 *
903 * It must be executed by a thread running in the cluster containing the parent directory.
904 * It can be the RPC_VFS_FS_ADD_DENTRY. This function does NOT take any lock.
905 ******************************************************************************************
906 * @ parent  : local pointer on parent (directory) inode.
907 * @ dentry  : local pointer on dentry containing name.
908 * @ return 0 if success / return -1 if device access failure.
909 *****************************************************************************************/
910error_t vfs_fs_add_dentry( vfs_inode_t  * parent,
911                           vfs_dentry_t * dentry );
912
913/******************************************************************************************
914 * This function updates the mapper associated to a directory inode identified by the
915 * <parent> argument, to remove an entry identified by the <dentry> argument.
916 * The directory inode descriptor and the dentry descriptor are in the same cluster.
917 * Depending on the file system type, it calls the proper, FS specific function.
918 * Finally, it synchronously updates the parent directory on IOC device.
919 *
920 * It must be executed by a thread running in the cluster containing the parent directory.
921 * It can be the RPC_VFS_VS_REMOVE_DENTRY. This function does NOT take any lock.
922 ******************************************************************************************
923 * @ parent  : local pointer on parent (directory) inode.
924 * @ dentry  : local pointer on dentry containing name.
925 * @ return 0 if success / return -1 if device access failure.
926 *****************************************************************************************/
927error_t vfs_fs_remove_dentry( vfs_inode_t  * parent,
928                              vfs_dentry_t * dentry );
929
930/******************************************************************************************
931 * This function scan the mapper of an an existing parent inode directory, identified by
932 * the <parent> argument to find a directory entry identified by the <name> argument,
933 * and updates both the child inode descriptor, identified by the <child_xp> argument,
934 * and the associated dentry descriptor :
935 * - It set the "size", and "extend" fields in inode descriptor.
936 * - It set the "extend" field in dentry descriptor.
937 * It is called by the vfs_lookup() function in case of miss.
938 *
939 * Depending on the file system type, it calls the relevant, FS specific function.
940 * It must be called by a thread running in the cluster containing the parent inode.
941 * This function does NOT take any lock.
942 ******************************************************************************************
943 * @ parent    : local pointer on parent inode (directory).
944 * @ name      : child name.
945 * @ child_xp  : extended pointer on remote child inode (file or directory)
946 * @ return 0 if success / return ENOENT if not found.
947 *****************************************************************************************/
948error_t vfs_fs_get_dentry( vfs_inode_t * parent,
949                           char        * name,
950                           xptr_t        child_xp );
951
952/******************************************************************************************
953 * This function scan the mapper of an an existing parent inode directory, identified by
954 * the <inode> argument and copy up to <max_dirent> valid dentries to a
955 * local dirent array, defined by the <array> argument. The <min_dentry> argument defines
956 * the index of the first dentry to copied to the target dirent array.
957 * This function returns in the <entries> buffer the number of dentries actually written,
958 * and signals in the <done> buffer when the last valid entry has been found.
959 * If the <detailed> argument is true, a dentry/inode couple that does not exist in
960 * the Inode Tree is dynamically created, and all dirent fiels are documented in the
961 * dirent array. Otherwise, only the dentry name is documented.
962 *
963 * Depending on the file system type, it calls the relevant, FS specific function.
964 * It must be called by a thread running in the cluster containing the parent inode.
965 * This function does NOT take any lock.
966 ******************************************************************************************
967 * @ inode      : [in]  local pointer on directory inode.
968 * @ array      : [in]  local pointer on array of dirents.
969 * @ max_dirent : [in]  max number of slots in dirent array.
970 * @ min_dentry : [in]  index of first dentry to be copied into array.
971 * @ detailed   : [in]  dynamic inode creation if true.
972 * @ entries    : [out] number of dentries actually copied into array.
973 * @ done       : [out] Boolean true when last entry found.
974 * @ return 0 if success / return -1 if failure.
975 *****************************************************************************************/
976error_t vfs_fs_get_user_dir( vfs_inode_t   * inode,
977                             struct dirent * array,
978                             uint32_t        max_dirent,
979                             uint32_t        min_dentry,
980                             bool_t          detailed,
981                             uint32_t      * entries,
982                             bool_t        * done );
983 
984/*****************************************************************************************
985 * This function  updates the FS on the IOC device for a given inode identified by
986 * the <inode> argument. It scan all pages registered in the associated mapper,
987 * and copies from mapper to device each page marked as dirty.
988 * WARNING : The target <inode> cannot be a directory, because all modifications in a
989 * directory are synchronously done on the IOC device by the two vfs_fs_add_dentry()
990 * and vfs_fs_remove_dentry() functions.
991 *
992 * Depending on the file system type, it calls the relevant, FS specific function.
993 * It must be called by a thread running in the inode cluster.
994 *****************************************************************************************
995 * @ inode   : local pointer on inode.
996 * @ return 0 if success / return EIO if failure during device access.
997 ****************************************************************************************/
998error_t vfs_fs_sync_inode( struct vfs_inode_s * inode );
999
1000/*****************************************************************************************
1001 * This function updates the FS defined by the <fs_type> argument on the IOC device
1002 * for the FAT itself. It scan all clusters registered in the FAT mapper, and copies
1003 * to device each page marked as dirty.
1004 *
1005 * Depending on the file system type, it calls the relevant, FS specific function.
1006 * It can be called by a thread running in any cluster.
1007 *****************************************************************************************
1008 * @ fs_type   : specific file system type.
1009 * @ return 0 if success / return EIO if failure during device access.
1010 ****************************************************************************************/
1011error_t vfs_fs_sync_fat( vfs_fs_type_t fs_type );
1012
1013/*****************************************************************************************
1014 * This function updates the free clusters info on the IOC device for the FS defined
1015 * by the <fs_type> argument.
1016 *
1017 * Depending on the file system type, it calls the relevant, FS specific function.
1018 * It can be called by a thread running in any cluster.
1019 *****************************************************************************************
1020 * @ fs_type   : specific file system type.
1021 * @ return 0 if success / return EIO if failure during device access.
1022 ****************************************************************************************/
1023error_t vfs_fs_sync_free_info( vfs_fs_type_t fs_type );
1024
1025/******************************************************************************************
1026 * This function allocates a free cluster from the FS identified by the <fs_type>
1027 * argument. It updates the selected FS File Allocation Table.
1028 *
1029 * Depending on the file system type, it calls the relevant, FS specific function.
1030 * It can be called by a thread running in any cluster.
1031 ******************************************************************************************
1032 * @ fs_type   : [in]  File System type.
1033 * @ cluster   : [out] cluster index in File system.
1034 * @ return 0 if success / return -1 if no free cluster
1035 *****************************************************************************************/
1036error_t vfs_fs_cluster_alloc( uint32_t   fs_type,
1037                              uint32_t * cluster );
1038
1039/******************************************************************************************
1040 * This function makes all I/O operations required to release all clusters allocated
1041 * on IOC device to a given inode, identified by the <inode_xp> argument.
1042 * Depending on the file system type, it calls the proper, FS specific function.
1043 * It is called by the vfs_unlink() function.
1044 * It can be executed by a thread running in any cluster.
1045 * This function does NOT take any lock.
1046 ******************************************************************************************
1047 * @ inode_xp  : extended pointer on inode.
1048 * @ return 0 if success / return -1 if device access failure.
1049 *****************************************************************************************/
1050error_t vfs_fs_release_inode( xptr_t  inode_xp ); 
1051
1052
1053#endif  /* _VFS_H_ */
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