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source: trunk/kernel/vfs/vfs.h @ 269

Last change on this file since 269 was 266, checked in by alain, 7 years ago
Implement vfs_lseek() function.
File size: 52.6 KB

Rev	Line
[1]	1	/*
	2	* vfs.h - Virtual File System definition.
	3	*
[23]	4	* Author Mohamed Lamine Karaoui (2014,2015)
	5	* Alain Greiner (2016,2017)
[1]	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
[14]	28	#include <kernel_config.h>
[1]	29	#include <hal_types.h>
	30	#include <hal_atomic.h>
	31	#include <remote_rwlock.h>
	32	#include <remote_spinlock.h>
	33	#include <spinlock.h>
	34	#include <list.h>
	35	#include <xlist.h>
	36	#include <slist.h>
	37	#include <bits.h>
	38	#include <xhtab.h>
	39	#include <errno.h>
	40	#include <metafs.h>
	41
	42	#include <fatfs.h>
	43	#include <ramfs.h>
[23]	44	#include <devfs.h>
[1]	45
	46	/** Forward declarations */
	47
	48	struct vfs_inode_s;
	49	struct vfs_dentry_t;
	50	struct vfs_ctx_t;
	51	struct vfs_file_ref_s;
	52	struct vfs_file_s;
	53
	54	struct vfs_inode_op_s;
	55	struct vfs_dentry_op_s;
	56	struct vfs_file_op_s;
	57	struct vfs_ctx_op_s;
	58
	59	struct vfs_lookup_cmd_s;
	60	struct vfs_lookup_rsp_s;
	61
	62	struct mapper_s;
	63	struct process_s;
	64	struct device_s;
	65	struct vseg_s;
[23]	66	struct page_s;
[1]	67
	68
[23]	69	/******************************************************************************************
	70	* These flags are used to define the working mode of the vfs_lookup() function.
	71	*****************************************************************************************/
[1]	72
[23]	73	#define VFS_LOOKUP_DIR 0x01 /* the searched inode is a directory */
	74	#define VFS_LOOKUP_OPEN 0x02 /* the search is for an open/opendir */
	75	#define VFS_LOOKUP_PARENT 0x04 /* return the parent inode (not the inode itself) */
	76	#define VFS_LOOKUP_CREATE 0x10 /* file must be created if missing */
	77	#define VFS_LOOKUP_EXCL 0x20 /* file cannot previously exist */
[1]	78
[23]	79	/******************************************************************************************
	80	* This define the masks for the POSIX access rights to inodes
	81	*****************************************************************************************/
[1]	82
[23]	83	#define VFS_ISUID 0x0004000
	84	#define VFS_ISGID 0x0002000
	85	#define VFS_ISVTX 0x0001000
[1]	86
	87	#define VFS_IRWXU 0x0000700
	88	#define VFS_IRUSR 0x0000400
	89	#define VFS_IWUSR 0x0000200
	90	#define VFS_IXUSR 0x0000100
[23]	91
[1]	92	#define VFS_IRWXG 0x0000070
	93	#define VFS_IRGRP 0x0000040
	94	#define VFS_IWGRP 0x0000020
	95	#define VFS_IXGRP 0x0000010
[23]	96
[1]	97	#define VFS_IRWXO 0x0000007
	98	#define VFS_IROTH 0x0000004
	99	#define VFS_IWOTH 0x0000002
	100	#define VFS_IXOTH 0x0000001
	101
	102	#define VFS_IREAD VFS_IRUSR
	103	#define VFS_IWRITE VFS_IWUSR
	104	#define VFS_IEXEC VFS_IXUSR
	105
	106
[23]	107	/******************************************************************************************
	108	* This structure defines informations common to all inodes and dentries
	109	* of a given file system. As it is declared a global variable in the kdata segment,
	110	* it is replicated in all clusters and handled as private by each OS intance.
	111	*****************************************************************************************/
[1]	112
[23]	113	typedef enum
	114	{
	115	FS_TYPE_DEVFS = 0,
	116	FS_TYPE_FATFS = 1,
	117	FS_TYPE_RAMFS = 2,
	118
	119	FS_TYPES_NR = 3,
	120	}
	121	vfs_fs_type_t;
[1]	122
[23]	123	typedef enum
	124	{
	125	CTX_ATTR_READ_ONLY = 0x01, /! write access prohibited /
	126	CTX_ATTR_SYNC = 0x10, /! synchronise FS on each write /
	127	}
	128	vfs_ctx_attr_t;
[1]	129
[23]	130	typedef struct vfs_ctx_s
	131	{
	132	vfs_fs_type_t type; /! File System type /
	133	uint32_t attr; /! global attributes for all files in FS /
[188]	134	uint32_t total_clusters; /! total number of clusters on device /
	135	uint32_t cluster_size; /! cluster size on device (bytes) /
	136	xptr_t vfs_root_xp; /! extended pointer on VFS root inode /
[23]	137	spinlock_t lock; /! lock protecting inum allocator /
	138	uint32_t bitmap[BITMAP_SIZE(CONFIG_VFS_MAX_INODES)]; /* inum allocator */
	139	void * extend; /! FS specific context extension /
	140	}
	141	vfs_ctx_t;
[1]	142
	143	/******************************************************************************************
	144	* This structure define a VFS inode.
	145	* It contains an extended pointer on the parent dentry, and (for directory only)
	146	* an hash table xhtab refering all children dentries.
	147	* The <parent> inode is unique for a directory (not hard links for directories).
	148	* For a file, the parent field points to the first dentry who created this inode.
[23]	149	* Syncrhonisation:
[10]	150	* - the main_lock (spinlock) is used during the inode tree traversal or for inode
	151	* modification (add/remove children).
	152	* - the data_lock (rwlock) is used during read/write accesses to the data stored
	153	* in the mapper.
	154	* - the mapper lock (rwlock) is only used during the radix tree traversal to return
[23]	155	* the relevant page for read/write.
[1]	156	*****************************************************************************************/
	157
[23]	158	/* this enum define the VFS inode types values */
	159
[10]	160	typedef enum
	161	{
[188]	162	INODE_TYPE_FILE = 0x001, /! file /
	163	INODE_TYPE_DIR = 0x002, /! directory /
	164	INODE_TYPE_FIFO = 0x004, /! POSIX named pipe /
	165	INODE_TYPE_PIPE = 0x008, /! POSIX anonymous pipe /
	166	INODE_TYPE_SOCK = 0x010, /! POSIX socket /
	167	INODE_TYPE_DEV = 0x020, /! device channel /
	168	INODE_TYPE_SYML = 0x080, /! symbolic link /
[10]	169	}
	170	vfs_inode_type_t;
	171
[23]	172	/* this enum define the VFS inode attributes values */
	173
[1]	174	typedef enum
	175	{
[23]	176	INODE_ATTR_DIRTY = 0x01, /* modified versus the value on device */
	177	INODE_ATTR_INLOAD = 0x04, /* loading from device in progress */
	178	INODE_ATTR_NEW = 0x08, /* not saved on device yet */
[1]	179	}
[10]	180	vfs_inode_attr_t;
[1]	181
	182	typedef struct vfs_inode_s
	183	{
[188]	184	struct vfs_ctx_s * ctx; /! local pointer on FS context /
	185	uint32_t gc; /! generation counter /
	186	uint32_t inum; /! inode identifier (unique in file system) /
	187	uint32_t attr; /! inode attributes (see above) /
	188	vfs_inode_type_t type; /! inode type (see above) /
	189	uint32_t size; /! number of bytes /
	190	uint32_t links; /! number of alias dentry /
	191	uid_t uid; /! user owner identifier /
	192	gid_t gid; /! group owner identifier /
	193	uint32_t rights; /! access rights /
	194	uint32_t refcount; /! reference counter (all pointers) /
	195	xptr_t parent_xp; /! extended pointer on parent dentry /
	196	xhtab_t children; /! embedded xhtab of children dentries /
	197	remote_rwlock_t data_lock; /! protect read/write to data and to size /
	198	remote_spinlock_t main_lock; /! protect inode tree traversal and modifs /
	199	list_entry_t list; /! member of set of inodes in same cluster /
	200	xlist_entry_t wait_root; /! root of threads waiting on this inode /
	201	struct mapper_s * mapper; /! associated file cache /
	202	void * extend; /! fs_type_specific inode extension /
[1]	203	}
	204	vfs_inode_t;
	205
	206	/******************************************************************************************
	207	* This structure defines a directory entry.
	208	* A dentry contains the name of a remote file/dir, an extended pointer on the
	209	* inode representing this file/dir, and a local pointer on the inode representing
	210	* the parent directory.
	211	*****************************************************************************************/
	212
	213	typedef struct vfs_dentry_s
	214	{
[188]	215	struct vfs_ctx_s * ctx; /! local pointer on FS context /
	216	char name[CONFIG_VFS_MAX_NAME_LENGTH];
	217	uint32_t length; /! name length (bytes) /
	218	uint32_t refcount; /! reference counter (all pointers) /
	219	struct vfs_inode_s * parent; /! local pointer on parent inode /
	220	xptr_t child_xp; /! extended pointer on child inode /
	221	xlist_entry_t list; /! member of list of dentries with same key /
	222	void * extend; /! FS specific extension /
[1]	223	}
	224	vfs_dentry_t;
	225
	226	/******************************************************************************************
[23]	227	* This file structure describes an open file/directory for a given process.
[1]	228	* It is not replicated, and is dynamically allocated in the cluster that contains
	229	* the inode, when a thread makes an open() or opendir() system call.
[23]	230	* It cannot exist a file structure without an inode structure.
[266]	231	* As the fd_array (containing extended pointers on the open file descriptors)
[23]	232	* is replicated in all process descriptors, we need a references counter.
[1]	233	*****************************************************************************************/
	234
	235	typedef enum
	236	{
[266]	237	VFS_SEEK_SET,
	238	VFS_SEEK_CUR,
	239	VFS_SEEK_END,
	240	}
	241	vfs_lseek_cmd_t;
	242
	243	typedef enum
	244	{
[23]	245	FD_ATTR_READ_ENABLE = 0x01, /! read access possible /
	246	FD_ATTR_WRITE_ENABLE = 0x02, /! write access possible /
	247	FD_ATTR_APPEND = 0x04, /! append on each write /
	248	FD_ATTR_CLOSE_EXEC = 0x08, /! close file on exec /
	249	FD_ATTR_SYNC = 0x10, /! synchronise FS on each write /
	250	FD_ATTR_IS_DIR = 0x20, /! this is a directory /
[1]	251	}
[23]	252	vfs_file_attr_t;
[1]	253
	254	typedef struct vfs_file_s
	255	{
[23]	256	struct vfs_ctx_s * ctx; /! local pointer on FS context. /
[1]	257	uint32_t gc; /! generation counter /
[23]	258	vfs_file_attr_t attr; /! file attributes bit vector (see above) /
	259	vfs_inode_type_t type; /! same type as inode /
[1]	260	uint32_t offset; /! seek position in file /
[23]	261	uint32_t refcount; /! all pointers on this file descriptor /
	262	remote_rwlock_t lock; /! protect offset modifications /
[1]	263	struct mapper_s * mapper; /! associated file cache /
	264	struct vfs_inode_s * inode; /! local pointer on associated inode /
[23]	265	void * extend; /! FS specific extension /
[1]	266	}
	267	vfs_file_t;
	268
	269	/******************************************************************************************
[23]	270	* This structure define the informations associated to a file descriptor,
	271	* returned to user space by the stat() system call.
[1]	272	*****************************************************************************************/
	273
	274	typedef struct vfs_stat_s
	275	{
	276	uint32_t dev; /! ID of device containing file /
	277	uint32_t ino; /! inode number /
	278	uint32_t mode; /! protection /
	279	uint32_t nlink; /! number of hard links /
	280	uint32_t uid; /! user ID of owner /
	281	uint32_t gid; /! group ID of owner /
	282	uint32_t rdev; /! device ID (if special file) /
	283	uint64_t size; /! total size, in bytes /
	284	uint32_t blksize; /! blocksize for file system I/O /
	285	uint32_t blocks; /! number of 512B blocks allocated /
	286	uint64_t atime; /! time of last access /
	287	uint64_t mtime; /! time of last modification /
	288	uint64_t ctime; /! time of last status change /
	289	}
	290	vfs_stat_t;
	291
[23]	292	/*********************************************************************************************
	293	* This structure defines the information associated to a directory entry,
	294	* returned to user space by the readdir() system call.
	295	********************************************************************************************/
[1]	296
[23]	297	typedef struct vfs_dirent_s
[1]	298	{
[23]	299	uint32_t inum; /! inode identifier /
	300	uint32_t type; /! inode type /
	301	char name[CONFIG_VFS_MAX_NAME_LENGTH]; /! dentry name /
[1]	302	}
[23]	303	vfs_dirent_t;
[1]	304
	305
	306
	307	/*****************************************************************************************/
	308	/****************** VFS global functions *********************************************/
	309	/*****************************************************************************************/
	310
	311
	312	/******************************************************************************************
[23]	313	* This function mount a given file system type for a given process TODO.
[1]	314	*****************************************************************************************/
	315	error_t vfs_mount_fs_root( struct device_s * device,
	316	uint32_t fs_type,
	317	struct process_s * process );
	318
	319
	320	/*****************************************************************************************/
[188]	321	/***************** VFS Context related functions **************************************/
[1]	322	/*****************************************************************************************/
	323
	324	/******************************************************************************************
[188]	325	* This function initialise a (statically allocated) VFS context in local cluster.
	326	******************************************************************************************
	327	* @ fs_type : file system type.
	328	* @ attr : global attributes (for all files in FS.
	329	* @ total_clusters : total number of clusters on device.
	330	* @ cluster_size : cluster size on device (bytes).
	331	* @ vfs_root_xp : extended pointer on VFS root inode.
	332	* @ extend : fs_type_specific extension.
	333	*****************************************************************************************/
	334	void vfs_ctx_init( vfs_fs_type_t type,
	335	uint32_t attr,
	336	uint32_t total_clusters,
	337	uint32_t cluster_size,
	338	xptr_t vfs_root_xp,
	339	void * extend );
	340
	341	/******************************************************************************************
[1]	342	* This function allocates an inode identifier from the local cluster inum allocator.
	343	* The inum respects a fixed format:
	344	* - the 16 MSB bits contain the cluster identifier : cxy
	345	* - the 16 LSB bits contains the local inode identifier : lid
	346	******************************************************************************************
	347	* @ ctx : local pointer on file system context.
	348	* @ inum : [ou] buffer for allocated inode identifier.
	349	* @ return 0 if success / return non-zero if error.
	350	*****************************************************************************************/
	351	error_t vfs_ctx_inum_alloc( vfs_ctx_t * ctx,
	352	uint32_t * inum );
	353
	354	/******************************************************************************************
	355	* This function release an inode identifier.
	356	******************************************************************************************
	357	* @ ctx : local pointer on file system context.
	358	* @ inum : released inode identifier.
	359	*****************************************************************************************/
	360	void vfs_ctx_inum_release( vfs_ctx_t * ctx,
	361	uint32_t inum );
	362
	363
	364
	365
	366	/*****************************************************************************************/
	367	/******************* Inode related functions *****************************************/
	368	/*****************************************************************************************/
	369
	370	/******************************************************************************************
	371	* This function allocates memory from local cluster for an inode descriptor and the
	372	* associated mapper. It initialise these descriptors from arguments values.
	373	* The parent dentry must have been previously created.
	374	* If the client thread is not running in the cluster containing this inode,
	375	* it must use the rpc_vfs_inode_create_client() function.
	376	******************************************************************************************
	377	* @ dentry_xp : extended pointer on associated dentry (in parent inode cluster).
[23]	378	* @ fs_type : file system type.
	379	* @ inode_type : inode type.
[188]	380	* @ extend : local pointer on vs_type_specific extension.
[1]	381	* @ attr : inode attributes.
[23]	382	* @ rights : inode access rights.
[1]	383	* @ uid : user owner ID.
	384	* @ gid : group owner ID.
	385	* @ inode_xp : [out] buffer for extended pointer on created inode.
	386	* # return 0 if success / return ENOMEM or EINVAL if error.
	387	*****************************************************************************************/
[23]	388	error_t vfs_inode_create( xptr_t dentry_xp,
	389	vfs_fs_type_t fs_type,
	390	vfs_inode_type_t inode_type,
[188]	391	void * extend,
[23]	392	uint32_t attr,
	393	uint32_t rights,
	394	uid_t uid,
	395	gid_t gid,
	396	xptr_t * inode_xp );
[1]	397
	398	/******************************************************************************************
	399	* This function releases memory allocated to an inode descriptor.
	400	* It must be executed by a thread running in the cluster containing the inode,
	401	* and the inode refcount must be zero.
	402	* If the client thread is not running in the owner cluster, it must use the
	403	* rpc_vfs_inode_destroy_client() function.
	404	******************************************************************************************
	405	* @ inode : local pointer on inode descriptor.
	406	*****************************************************************************************/
	407	void vfs_inode_destroy( vfs_inode_t * inode );
	408
[238]	409	/******************************************************************************************
	410	* This function scan an existing parent inode directory, identified by the <parent>
	411	* argument to find a directory entry identified by the <name> argument, and update
	412	* the remote child inode, identified by the <child_xp> argument.
	413	* Depending on the file system type, it calls the relevant, FS specific function,
	414	* to scan the directory, and set the "type", "size", and "extend" fields.
	415	* It must be called by a thread running in the cluster containing the parent inode.
	416	******************************************************************************************
	417	* @ parent : local pointer on parent inode (directory).
	418	* @ name : child name.
	419	* @ child_xp : extended pointer on remote child inode (file or directory)
	420	* @ return 0 if success / return ENOENT if not found.
	421	*****************************************************************************************/
	422	error_t vfs_inode_load( vfs_inode_t * parent,
	423	char * name,
	424	xptr_t child_xp );
	425
[1]	426	/******************************************************************************************
[23]	427	* This function atomically increment/decrement the inode refcount.
[1]	428	* It can be called by any thread running in any cluster.
	429	*****************************************************************************************/
	430	void vfs_inode_remote_up( xptr_t inode_xp );
	431	void vfs_inode_remote_down( xptr_t inode_xp );
	432
	433	/******************************************************************************************
	434	* This function returns the <size> of a file/dir from a remote inode,
	435	* taking the remote_rwlock protecting <size> in READ_MODE.
	436	*****************************************************************************************
	437	* @ inode_xp : extended pointer on the remote inode.
	438	* @ return the current size.
	439	*****************************************************************************************/
	440	uint32_t vfs_inode_get_size( xptr_t inode_xp );
	441
	442	/******************************************************************************************
	443	* This function set the <size> of a file/dir to a remote inode,
	444	* taking the remote_rwlock protecting <size> in WRITE_MODE.
	445	*****************************************************************************************
	446	* @ inode_xp : extended pointer on the remote inode.
	447	* @ size : value to be written.
	448	*****************************************************************************************/
	449	void vfs_inode_set_size( xptr_t inode_xp,
	450	uint32_t size );
	451
	452	/******************************************************************************************
	453	* This function takes the main lock of a remote inode.
	454	* This lock protect all inode fiels, including the children dentries.
	455	*****************************************************************************************
	456	* @ inode_xp : extended pointer on the remote inode.
	457	*****************************************************************************************/
[101]	458	void vfs_inode_lock( xptr_t inode_xp );
[1]	459
	460	/******************************************************************************************
	461	* This function releases the main lock of a remote inode.
	462	* This lock protect all inode fiels, including the children dentries.
	463	*****************************************************************************************
	464	* @ inode_xp : extended pointer on the remote inode.
	465	*****************************************************************************************/
[101]	466	void vfs_inode_unlock( xptr_t inode_xp );
[1]	467
	468	/******************************************************************************************
[101]	469	* This debug function returns the current owner of the inode main lock.
	470	*****************************************************************************************
	471	* @ inode_xp : extended pointer on the remote inode.
	472	* @ return extended pointer on owner thread / return XPTR_NULL if lock not taken.
[1]	473	*****************************************************************************************/
[101]	474	xptr_t vfs_inode_owner( xptr_t inode_xp );
[1]	475
	476	/******************************************************************************************
[204]	477	* This debug function diplays the name of the inode identified by the <inode_xp>
	478	* argument, and all children names for a directory.
	479	*****************************************************************************************
	480	* @ inode_xp : extended pointer on the remote inode.
	481	*****************************************************************************************/
	482	void vfs_inode_display( xptr_t inode_xp );
	483
	484
	485
	486
	487
	488
	489	/******************************************************************************************
[1]	490	* This function TODO
	491	*****************************************************************************************/
	492	error_t vfs_inode_trunc( vfs_inode_t * inode );
	493
	494	/******************************************************************************************
	495	* This function TODO
	496	*****************************************************************************************/
	497	error_t vfs_inode_link( vfs_inode_t * inode,
	498	uint32_t igc );
	499
	500	/******************************************************************************************
	501	* This function TODO
	502	*****************************************************************************************/
	503	error_t vfs_inode_unlink( vfs_inode_t * inode );
	504
	505	/******************************************************************************************
	506	* This function TODO
	507	*****************************************************************************************/
	508	error_t vfs_inode_stat( vfs_inode_t * inode,
	509	uint32_t inum );
	510
	511	/******************************************************************************************
	512	* This function TODO
	513	*****************************************************************************************/
	514	error_t vfs_icache_del( vfs_inode_t * inode );
	515
	516
	517	/******************************************************************************************
	518	* This function TODO Pourquoi 2 arguments ?
	519	*****************************************************************************************/
	520	error_t vfs_stat_inode( vfs_inode_t * inode,
	521	uint32_t inum );
	522
	523
	524	/*****************************************************************************************/
	525	/*************** Dentry related functions ********************************************/
	526	/*****************************************************************************************/
	527
	528	/******************************************************************************************
	529	* This function allocates memory from local cluster for a dentry descriptor,
	530	* initialises it from arguments values, and returns the extended pointer on dentry.
	531	* The inode field is not initialized, because the inode does not exist yet.
	532	* If the client thread is not running in the target cluster for this inode,
	533	* it must use the rpc_dentry_create_client() function.
	534	******************************************************************************************
[23]	535	* @ fs_type : file system type.
[1]	536	* @ name : directory entry file/dir name.
	537	* @ parent : local pointer on parent inode.
[23]	538	* @ dentry_xp : [out] buffer for extended pointer on created dentry.
[1]	539	* @ return 0 if success / return ENOMEM or EINVAL if error.
	540	*****************************************************************************************/
[23]	541	error_t vfs_dentry_create( vfs_fs_type_t fs_type,
	542	char * name,
	543	vfs_inode_t * parent,
	544	xptr_t * dentry_xp );
[1]	545
	546	/******************************************************************************************
	547	* This function releases memory allocated to a dentry descriptor.
	548	* It must be executed by a thread running in the cluster containing the dentry,
	549	* and the dentry refcount must be zero.
	550	* If the client thread is not running in the owner cluster, it must use the
	551	* rpc_dentry_destroy_client() function.
	552	******************************************************************************************
	553	* @ dentry : local pointer on dentry descriptor.
	554	*****************************************************************************************/
	555	void vfs_dentry_destroy( vfs_dentry_t * dentry );
	556
	557	/******************************************************************************************
[23]	558	* These functions atomically increment/decrement the dentry refcount.
[1]	559	* It can be called by any thread running in any cluster.
	560	*****************************************************************************************/
	561	void vfs_dentry_remote_up( xptr_t dentry_xp );
[23]	562	void vfs_dentry_remote_down( xptr_t dentry_xp );
[1]	563
[23]	564
	565	/*****************************************************************************************/
	566	/********************** File descriptor related functions ****************************/
	567	/*****************************************************************************************/
	568
[1]	569	/******************************************************************************************
[23]	570	* This function allocates memory and initializes a new local file descriptor.
	571	* It must be executed in the cluster containing the inode.
	572	* If the client thread is not running in the owner cluster, it must use the
	573	* rpc_vfs_file_create_client() function.
	574	******************************************************************************************
	575	* @ inode : local pointer on associated inode.
	576	* @ attr : file descriptor attributes.
	577	* @ file_xp : [out] buffer for extended pointer on created file descriptor.
	578	* @ return 0 if success / return ENOMEM if error.
[1]	579	*****************************************************************************************/
[23]	580	error_t vfs_file_create( vfs_inode_t * inode,
	581	uint32_t attr,
	582	xptr_t * file_xp );
[1]	583
[23]	584	/******************************************************************************************
	585	* This function releases memory allocated to a local file descriptor.
	586	* It must be executed by a thread running in the cluster containing the inode,
	587	* and the file refcount must be zero.
	588	* If the client thread is not running in the owner cluster, it must use the
	589	* rpc_vfs_file_destroy_client() function.
	590	******************************************************************************************
	591	* @ file : local pointer on file descriptor.
	592	*****************************************************************************************/
	593	void vfs_file_destroy( vfs_file_t * file );
[1]	594
[23]	595	/******************************************************************************************
	596	* These functions increment (resp. decrement) the count field in a remote file
	597	* descriptor, using a remote_atomic access.
	598	*****************************************************************************************/
	599	void vfs_file_count_up ( xptr_t file_xp );
	600	void vfs_file_count_down( xptr_t file_xp );
	601
	602
	603
[1]	604	/*****************************************************************************************/
[23]	605	/***************** Inode-Tree related functions **************************************/
[1]	606	/*****************************************************************************************/
	607
	608	/******************************************************************************************
[188]	609	* This function randomly selects a cluster for a new inode.
	610	******************************************************************************************
	611	* @ returns the selected cluster identifier.
	612	*****************************************************************************************/
	613	cxy_t vfs_cluster_random_select();
	614
	615	/******************************************************************************************
[1]	616	* This function returns in a kernel buffer allocated by the caller function,
	617	* the pathname of a file/dir identified by an extended pointer on the inode.
	618	* It traverse the Inode Tree from the target node to the root.
	619	* It can be called by any thread running in any cluster.
	620	******************************************************************************************
	621	* @ inode_xp : pointer on inode descriptor.
	622	* @ buffer : kernel buffer for pathname (must be allocated by caller).
	623	* @ size : max number of characters in buffer.
	624	* @ return 0 if success / return EINVAL if buffer too small.
	625	*****************************************************************************************/
	626	error_t vfs_get_path( xptr_t inode_xp,
	627	char * buffer,
	628	uint32_t max_size );
	629
	630	/******************************************************************************************
	631	* This function takes a pathname (absolute or relative to cwd) and returns an extended
[23]	632	* pointer on the associated inode.
	633	* - If a given name in the path is not found in the inode tree, it try to load the missing
	634	* dentry/inode couple, from informations found in the parent directory.
	635	* - If this directory entry does not exist on device, it returns an error.
	636	* - If the the file identified by the pathname does not exist on device but the
	637	* flag CREATE is set, the inode is created.
	638	* - If the the file identified by the pathname exist on device but both flags EXCL
	639	* and CREATE are set, an error is returned.
[1]	640	******************************************************************************************
[23]	641	* @ cwd_xp : extended pointer on current directory (for relative path).
	642	* @ pathname : path in kernel space (can be relative or absolute).
	643	* @ lookup_mode : flags defining the working mode (defined above in this file).
[238]	644	* @ inode_xp : [out] buffer for extended pointer on searched inode.
[23]	645	* @ return 0 if success / ENOENT if inode not found , EACCES if permissopn denied,
	646	* EAGAIN if a new complete lookup must be made
[1]	647	*****************************************************************************************/
[23]	648	error_t vfs_lookup( xptr_t cwd_xp,
	649	char * pathname,
	650	uint32_t lookup_mode,
	651	xptr_t * inode_xp );
[1]	652
	653	/******************************************************************************************
	654	* This function creates a new couple dentry/inode, and insert it in the Inode-Tree.
	655	* It can be executed by any thread running in any cluster, as this function
	656	* uses the rpc_dentry_create_client() and rpc_inode_create client() if required.
[204]	657	* This is done in three steps:
	658	* 1) The dentry is created in the cluster containing the existing <parent_xp> inode.
	659	* The new dentry name is defined by the <name> argument.
	660	* 2) The inode and its associated mapper are created in cluster identified by <child_cxy>.
	661	* The new inode and the parent inode can have different FS types.
[238]	662	* 3) The "child_xp" field in created dentry (pointing on the created inode) is updated.
[1]	663	******************************************************************************************
[188]	664	* @ child_cxy : target cluster for child inode.
[23]	665	* @ inode_type : new inode type
	666	* @ fs_type : new inode FS type.
[1]	667	* @ parent_xp : extended pointer on parent inode.
	668	* @ name : new directory entry name.
[188]	669	* @ extend : fs_type_specific inode extension.
[1]	670	* @ child_xp : [out] buffer for extended pointer on child inode.
[204]	671	* @ return 0 if success / ENOMEM if dentry or inode cannot be created.
[1]	672	*****************************************************************************************/
[188]	673	error_t vfs_add_child_in_parent( cxy_t child_cxy,
	674	vfs_inode_type_t inode_type,
[23]	675	vfs_fs_type_t fs_type,
	676	xptr_t parent_xp,
	677	char * name,
[188]	678	void * extend,
[23]	679	xptr_t * child_xp );
[1]	680
	681	/******************************************************************************************
[23]	682	* This function removes a couple dentry/inode from the Inode-Tree, and remove it from
	683	* the external device.
	684	* TODO
[1]	685	******************************************************************************************
	686	* @ child_xp : extended pointer on removed inode.
	687	*****************************************************************************************/
	688	error_t vfs_remove_child_from_parent( xptr_t child_xp );
	689
[188]	690	/******************************************************************************************
	691	* This recursive function diplays a complete inode/dentry sub-tree.
	692	* Any inode can be selected as the sub-tree root.
[238]	693	* TODO this function is not protected against a concurrent inode/dentry removal...
[188]	694	******************************************************************************************
	695	* @ inode_xp : extended pointer on sub-tree root inode.
	696	*****************************************************************************************/
	697	void vfs_display( xptr_t inode_xp );
[23]	698
	699
	700
	701
	702
[1]	703	/*****************************************************************************************/
[23]	704	/**************** File access API ****************************************************/
[1]	705	/*****************************************************************************************/
	706
	707	/******************************************************************************************
	708	* This function allocates a vfs_file_t structure in the cluster containing the inode
[23]	709	* associated to the file identified by <cwd_xp> & <path>.
	710	* It initializes it, register it in the reference process fd_array, and returns both
	711	* the extended pointer on the remote file descriptor, and the index in the fd_array.
[1]	712	* The pathname can be relative to current directory or absolute.
[23]	713	* If the inode does not exist in the inode cache, it try to find the file on the mounted
[1]	714	* device, and creates an inode on a pseudo randomly selected cluster if found.
	715	* It the requested file does not exist on device, it creates a new inode if the
	716	* O_CREAT flag is set and return an error otherwise.
	717	******************************************************************************************
[23]	718	* @ cwd_xp : extended pointer on current working directory file descriptor.
	719	* @ path : file pathname (absolute or relative to current directory).
	720	* @ flags : defined above
	721	* @ mode : access rights (as defined by chmod)
	722	* @ file_xp : [out] buffer for extended pointer on created remote file descriptor.
	723	* @ file_id : [out] buffer for created file descriptor index in reference fd_array.
[1]	724	* @ return 0 if success / return non-zero if error.
	725	*****************************************************************************************/
	726	error_t vfs_open( xptr_t cwd_xp,
	727	char * path,
	728	uint32_t flags,
[23]	729	uint32_t mode,
	730	xptr_t * file_xp,
	731	uint32_t * file_id );
[1]	732
	733	/******************************************************************************************
[23]	734	* This function moves <size> bytes between the file identified by the open file descriptor
[265]	735	* <file_xp> and a local kernel or user <buffer>, as defined by the <is_user> argument,
	736	* and taken into account the offset in <file_xp>.
[23]	737	* The transfer direction is defined by the <to_buffer> argument.
	738	******************************************************************************************
[265]	739	* @ to_buffer : mapper -> buffer if true / buffer -> mapper if false.
	740	* @ is_user : user space buffer if true / local kernel buffer if false.
[23]	741	* @ file_xp : extended pointer on the remote file descriptor.
[265]	742	* @ buffer : local pointer on buffer.
[1]	743	* @ size : requested number of bytes from offset.
	744	* @ returns number of bytes actually transfered / -1 if error.
	745	*****************************************************************************************/
[23]	746	error_t vfs_move( bool_t to_buffer,
[265]	747	bool_t is_user,
[23]	748	xptr_t file_xp,
	749	void * buffer,
	750	uint32_t size );
[1]	751
	752	/******************************************************************************************
	753	* This function set a new value in the offset of the open file descriptor <file_xp>.
	754	* This value depends on the <whence> argument:
	755	* - if VFS_SEEK_SET, new value is <offset>
	756	* - if VFS_SEEK_CUR, new value is current_offset + <offset>
	757	* - if VFS_SEEK_END, new value is file_size + <offset>
	758	******************************************************************************************
	759	* @ file_xp : extended pointer on the remote open file descriptor.
	760	* @ offset : local pointer on source kernel buffer.
	761	* @ whence : VFS_SEEK_SET / VFS_SEEK_CUR / VFS_SEEK_END.
	762	* @ new_offset : [out] buffer for new offset value.
	763	* @ returns 0 if success / -1 if error.
	764	*****************************************************************************************/
	765	error_t vfs_lseek( xptr_t file_xp,
	766	uint32_t offset,
	767	uint32_t whence,
	768	uint32_t * new_offset );
	769
	770	/******************************************************************************************
[23]	771	* This function close an open file descriptor:
	772	* 1) All entries in fd_array copies are directly cancelled by the calling thread,
	773	* using remote accesses.
	774	* 2) The memory allocated to file descriptor in cluster containing the inode is released.
	775	* It requires a RPC if cluster containing the file descriptor is remote.
[1]	776	******************************************************************************************
	777	* @ file_xp : extended pointer on the file descriptor.
[23]	778	* @ file_id : file descriptor index in fd_array.
	779	* @ returns 0 if success / -1 if error.
[1]	780	*****************************************************************************************/
[23]	781	error_t vfs_close( xptr_t file_xp,
	782	uint32_t file_id );
[1]	783
	784	/******************************************************************************************
[23]	785	* This function remove from the file system a directory entry identified by the
	786	* <cwd_xp> & <path> arguments.
[1]	787	******************************************************************************************
[23]	788	* @ cwd_xp : extended pointer on the current working directory file descriptor.
[1]	789	* @ path : pathname (absolute or relative to current directory).
[23]	790	* @ returns 0 if success / -1 if error.
[1]	791	*****************************************************************************************/
	792	error_t vfs_unlink( xptr_t cwd_xp,
	793	char * path );
	794
	795	/******************************************************************************************
[23]	796	* This function returns, in the structure pointed by the <k_stat> kernel pointer,
	797	* various informations on the file descriptor identified by the <file_xp> argument.
	798	* TODO not implemented yet...
	799	******************************************************************************************
	800	* @ file_xp : extended pointer on the file descriptor of the searched directory .
	801	* @ k_dirent : local pointer on the dirent_t structure in kernel space.
	802	* @ returns 0 if success / -1 if error.
[1]	803	*****************************************************************************************/
	804	error_t vfs_stat( xptr_t file_xp,
[23]	805	vfs_stat_t * k_stat );
[1]	806
	807	/******************************************************************************************
[23]	808	* This function returns, in the structure pointed by the <k_dirent> kernel pointer,
	809	* various infos on the directory entry currently pointed by the <file_xp> file descriptor.
	810	* TODO not implemented yet...
	811	******************************************************************************************
	812	* @ file_xp : extended pointer on the file descriptor of the searched directory .
	813	* @ k_dirent : local pointer on the dirent_t structure in kernel space.
	814	* @ returns 0 if success / -1 if error.
[1]	815	*****************************************************************************************/
[23]	816	error_t vfs_readdir( xptr_t file_xp,
	817	vfs_dirent_t * k_dirent );
[1]	818
	819	/******************************************************************************************
[23]	820	* This function creates a new inode and associated dentry for the directory defined
	821	* by the <cwd_xp> & <path> arguments.
	822	* TODO not implemented yet...
	823	******************************************************************************************
	824	* @ cwd_xp : extended pointer on the current working directory file descriptor.
	825	* @ path : pathname (absolute or relative to current directory).
	826	* @ mode : access rights (as defined by chmod)
	827	* @ returns 0 if success / -1 if error.
[1]	828	*****************************************************************************************/
[23]	829	error_t vfs_mkdir( xptr_t cwd_xp,
	830	char * path,
	831	uint32_t mode );
[1]	832
	833	/******************************************************************************************
[23]	834	* This function remove a directory identified by the <cwd_xp / path> arguments
	835	* from the file system.
	836	* TODO not implemented yet...
	837	******************************************************************************************
	838	* @ cwd_xp : extended pointer on the current working directory file descriptor.
	839	* @ path : pathname (absolute or relative to current directory).
	840	* @ returns 0 if success / -1 if error.
[1]	841	*****************************************************************************************/
[23]	842	error_t vfs_rmdir( xptr_t cwd_xp,
	843	char * path );
[1]	844
	845	/******************************************************************************************
[23]	846	* This function makes the directory identified by <cwd_xp / path> arguments to become
	847	* the working directory for the calling process.
	848	******************************************************************************************
	849	* @ cwd_xp : extended pointer on current directory file descriptor (relative path).
	850	* @ path : file pathname (absolute or relative to current directory).
	851	* return 0 if success / -1 if error.
[1]	852	*****************************************************************************************/
[23]	853	error_t vfs_chdir( xptr_t cwd_xp,
	854	char * path );
[1]	855
	856	/******************************************************************************************
[23]	857	* This function change the access rigths for the file identified by the <cwd_xp / path>
	858	* arguments. The new access rights are defined by the <mode> argument value.
	859	******************************************************************************************
	860	* @ cwd_xp : extended pointer on current directory file descriptor (relative path).
	861	* @ path : file pathname (absolute or relative to current directory).
	862	* @ mode : access rights new value.
	863	* return 0 if success / -1 if error.
[1]	864	*****************************************************************************************/
[23]	865	error_t vfs_chmod( xptr_t cwd_xp,
	866	char * path,
	867	uint32_t mode );
[1]	868
	869	/******************************************************************************************
[23]	870	* This function creates a named FIFO file.
	871	* TODO not implemented yet
	872	******************************************************************************************
	873	* @ path : FIFO pathname (absolute or relative to current directory).
	874	* @ cwd_xp : extended pointer on the current working directory file descriptor.
	875	* @ mode : access rights new value.
[1]	876	*****************************************************************************************/
[23]	877	error_t vfs_mkfifo( xptr_t cwd_xp,
	878	char * path,
	879	uint32_t mode );
[1]	880
	881
	882	/*****************************************************************************************/
[23]	883	/**************** Mapper access API **************************************************/
[1]	884	/*****************************************************************************************/
	885
[23]	886	/******************************************************************************************
[238]	887	* This function makes an I/O operation to move one page to/from device from/to the mapper.
	888	* It is used in case of MISS on the mapper, or when a dirty page in the mapper must
	889	* be updated in the File System.
[23]	890	* Depending on the file system type, it calls the proper, FS specific function.
	891	* It must be executed by a thread running in the cluster containing the mapper.
	892	* The mapper pointer is obtained from the page descriptor.
	893	* It takes the mapper lock before launching the IO operation.
	894	******************************************************************************************
[238]	895	* @ page : local pointer on the page descriptor.
	896	* @ to_mapper : transfer direction.
[23]	897	* @ returns 0 if success / return EINVAL if it cannot access the external device.
[1]	898	*****************************************************************************************/
[238]	899	error_t vfs_mapper_move_page( struct page_s * page,
	900	bool_t to_mapper );
[1]	901
[23]	902	/******************************************************************************************
[239]	903	* This function makes I/O operations to move, from device to mapper, all pages covering
	904	* a given inode, identified by the <inode> argument. Inode be a directory or a file,
	905	* but this function is mainly used to load (prefetch) a complete directory to the mapper.
[23]	906	* Depending on the file system type, it calls the proper, FS specific function.
	907	* It must be executed by a thread running in the cluster containing the mapper.
[238]	908	* The mapper pointer is obtained from the inode descriptor.
[23]	909	* It takes the mapper lock before launching the IO operation.
	910	******************************************************************************************
[238]	911	* @ inode : local pointer on inode.
	912	* @ return 0 if success / return EIO if device access failure.
[1]	913	*****************************************************************************************/
[238]	914	error_t vfs_mapper_load_all( vfs_inode_t * inode );
[1]	915
	916
	917
[23]	918	/* deprecated [AG]
	919
	920	typedef error_t (lookup_inode_t) ( vfs_inode_t * parent ,
	921	vfs_dentry_t * dentry );
	922
	923	typedef error_t (write_inode_t) ( vfs_inode_t * inode );
	924
	925	typedef error_t (release_inode_t) ( vfs_inode_t * inode );
	926
	927	typedef error_t (unlink_inode_t) ( vfs_inode_t * parent,
	928	vfs_dentry_t * dentry,
	929	uint32_t flags );
	930
	931	typedef error_t (stat_inode_t) ( vfs_inode_t * inode );
	932
	933	typedef error_t (trunc_inode_t) ( vfs_inode_t * inode );
	934
	935	typedef error_t (delete_inode_t) ( vfs_inode_t * inode );
	936
	937	typedef struct vfs_inode_op_s
	938	{
	939	init_inode_t * init;
	940	create_inode_t * create;
	941	lookup_inode_t * lookup;
	942	write_inode_t * write;
	943	release_inode_t * release;
	944	unlink_inode_t * unlink;
	945	delete_inode_t * delete;
	946	stat_inode_t * stat;
	947	trunc_inode_t * trunc; // change the size of a file
	948	}
	949	vfs_inode_op_t;
	950
	951	******************************************************************************************
	952	* These typedef define the set of FS specific operations on a VFS DENTRY descriptor.
	953	* They must be implemented by any specific file system to be supported by ALMOS_MKH.
	954	* This code is not actually used, and is only defined for documentation
	955	******************************************************************************************
	956
	957
	958	typedef error_t (vfs_compare_dentry_t) ( char * first , char * second );
	959
	960	typedef struct vfs_dentry_op_s
	961	{
	962	vfs_compare_dentry_t * compare;
	963	}
	964	vfs_dentry_op_t;
	965
	966
	967	******************************************************************************************
	968	* These typedef define the set of FS specific operations on FILE descriptors
	969	* They must be implemented by any specific file system to be supported by ALMOS_MKH.
	970	* This code is not actually used, and is only defined for documentation
	971	******************************************************************************************
	972
	973
	974	typedef error_t (open_file_t ) ( vfs_file_t * file,
	975	void * extend );
	976
	977	typedef error_t (read_file_t ) ( vfs_file_t * file,
	978	char * buffer,
	979	uint32_t count );
	980
	981	typedef error_t (write_file_t ) ( vfs_file_t * file,
	982	char * buffer,
	983	uint32_t count );
	984
	985	typedef error_t (lseek_file_t ) ( vfs_file_t * file );
	986
	987	typedef error_t (close_file_t ) ( vfs_file_t * file );
	988
	989	typedef error_t (release_file_t) ( vfs_file_t * file );
	990
	991	typedef error_t (read_dir_t ) ( vfs_file_t * file );
	992
	993	typedef error_t (mmap_file_t ) ( vfs_file_t * file ,
	994	struct vseg_s * vseg );
	995
	996	typedef error_t (munmap_file_t ) ( vfs_file_t * file,
	997	struct vseg_s * vseg );
	998
	999	typedef struct vfs_file_op_s
	1000	{
	1001	open_file_t * open;
	1002	read_file_t * read;
	1003	write_file_t * write;
	1004	lseek_file_t * lseek;
	1005	read_dir_t * readdir;
	1006	close_file_t * close;
	1007	release_file_t * release;
	1008	mmap_file_t * mmap;
	1009	munmap_file_t * munmap;
	1010	}
	1011	vfs_file_op_t;
	1012
	1013	*/
	1014
[1]	1015	#endif /* _VFS_H_ */

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