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source: trunk/kernel/vfs/vfs.h @ 29

Last change on this file since 29 was 23, checked in by alain, 7 years ago
Introduce syscalls.
File size: 49.1 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 /
	134	uint32_t count; /! total number of clusters on device /
	135	uint32_t blksize; /! device cluster size (bytes) /
	136	xptr_t root_xp; /! extended pointer on root inode /
	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	{
[23]	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_SOCKET = 0x010, /! POSIX socket /
	167	INODE_TYPE_DEV = 0x020, /! character peripheral 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	{
[23]	184	struct vfs_ctx_s * ctx; /! local pointer on FS context /
[1]	185	uint32_t gc; /! generation counter /
	186	uint32_t inum; /! inode identifier (unique in file system) /
	187	uint32_t attr; /! inode attributes (see above) /
[23]	188	vfs_inode_type_t type; /! inode type (see above) /
[1]	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 /
[23]	193	uint32_t rights; /! access rights /
[1]	194	uint32_t refcount; /! reference counter (all pointers) /
	195	xptr_t parent_xp; /! extended pointer on parent dentry /
[23]	196	xhtab_t children; /! embedded xhtab of vfs_dentry_t /
[10]	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 /
[23]	199	list_entry_t list; /! member of set of inodes in same cluster /
[1]	200	xlist_entry_t wait_root; /! root of threads waiting on this inode /
	201	struct vfs_inode_op_s * op; /! TODO ??? /
	202	struct mapper_s * mapper; /! associated file cache /
	203	void * extend; /! FS specific inode extension /
	204	}
	205	vfs_inode_t;
	206
	207	/******************************************************************************************
	208	* This structure defines a directory entry.
	209	* A dentry contains the name of a remote file/dir, an extended pointer on the
	210	* inode representing this file/dir, and a local pointer on the inode representing
	211	* the parent directory.
	212	*****************************************************************************************/
	213
	214	typedef struct vfs_dentry_s
	215	{
	216	struct vfs_ctx_s * ctx; /! local pointer on FS context /
	217	char name[CONFIG_VFS_MAX_NAME_LENGTH];
	218	uint32_t length; /! name length (bytes) /
	219	uint32_t refcount; /! reference counter (all pointers) /
	220	struct vfs_inode_s * parent; /! local pointer on parent inode /
	221	xptr_t child_xp; /! extended pointer on child inode /
	222	xlist_entry_t xlist; /! member of xlist of dentries with same key /
	223	struct vfs_dentry_op_s * op; /! TODO /
	224	void * extend; /! FS specific extension /
	225	}
	226	vfs_dentry_t;
	227
	228	/******************************************************************************************
[23]	229	* This file structure describes an open file/directory for a given process.
[1]	230	* It is not replicated, and is dynamically allocated in the cluster that contains
	231	* the inode, when a thread makes an open() or opendir() system call.
[23]	232	* It cannot exist a file structure without an inode structure.
	233	* Aa the fd_array (containing extended pointers on the open file descriptors)
	234	* is replicated in all process descriptors, we need a references counter.
[1]	235	*****************************************************************************************/
	236
	237	typedef enum
	238	{
[23]	239	FD_ATTR_READ_ENABLE = 0x01, /! read access possible /
	240	FD_ATTR_WRITE_ENABLE = 0x02, /! write access possible /
	241	FD_ATTR_APPEND = 0x04, /! append on each write /
	242	FD_ATTR_CLOSE_EXEC = 0x08, /! close file on exec /
	243	FD_ATTR_SYNC = 0x10, /! synchronise FS on each write /
	244	FD_ATTR_IS_DIR = 0x20, /! this is a directory /
[1]	245	}
[23]	246	vfs_file_attr_t;
[1]	247
	248	typedef struct vfs_file_s
	249	{
[23]	250	struct vfs_ctx_s * ctx; /! local pointer on FS context. /
[1]	251	uint32_t gc; /! generation counter /
[23]	252	vfs_file_attr_t attr; /! file attributes bit vector (see above) /
	253	vfs_inode_type_t type; /! same type as inode /
[1]	254	uint32_t offset; /! seek position in file /
[23]	255	uint32_t refcount; /! all pointers on this file descriptor /
	256	remote_rwlock_t lock; /! protect offset modifications /
[1]	257	struct mapper_s * mapper; /! associated file cache /
	258	struct vfs_inode_s * inode; /! local pointer on associated inode /
[23]	259	void * extend; /! FS specific extension /
[1]	260	}
	261	vfs_file_t;
	262
	263	/******************************************************************************************
[23]	264	* This structure define the informations associated to a file descriptor,
	265	* returned to user space by the stat() system call.
[1]	266	*****************************************************************************************/
	267
	268	typedef struct vfs_stat_s
	269	{
	270	uint32_t dev; /! ID of device containing file /
	271	uint32_t ino; /! inode number /
	272	uint32_t mode; /! protection /
	273	uint32_t nlink; /! number of hard links /
	274	uint32_t uid; /! user ID of owner /
	275	uint32_t gid; /! group ID of owner /
	276	uint32_t rdev; /! device ID (if special file) /
	277	uint64_t size; /! total size, in bytes /
	278	uint32_t blksize; /! blocksize for file system I/O /
	279	uint32_t blocks; /! number of 512B blocks allocated /
	280	uint64_t atime; /! time of last access /
	281	uint64_t mtime; /! time of last modification /
	282	uint64_t ctime; /! time of last status change /
	283	}
	284	vfs_stat_t;
	285
[23]	286	/*********************************************************************************************
	287	* This structure defines the information associated to a directory entry,
	288	* returned to user space by the readdir() system call.
	289	********************************************************************************************/
[1]	290
[23]	291	typedef struct vfs_dirent_s
[1]	292	{
[23]	293	uint32_t inum; /! inode identifier /
	294	uint32_t type; /! inode type /
	295	char name[CONFIG_VFS_MAX_NAME_LENGTH]; /! dentry name /
[1]	296	}
[23]	297	vfs_dirent_t;
[1]	298
	299
	300
	301	/*****************************************************************************************/
	302	/****************** VFS global functions *********************************************/
	303	/*****************************************************************************************/
	304
	305
	306	/******************************************************************************************
[23]	307	* This function mount a given file system type for a given process TODO.
[1]	308	*****************************************************************************************/
	309	error_t vfs_mount_fs_root( struct device_s * device,
	310	uint32_t fs_type,
	311	struct process_s * process );
	312
	313
	314	/*****************************************************************************************/
	315	/***************** FS Context related functions **************************************/
	316	/*****************************************************************************************/
	317
	318	/******************************************************************************************
	319	* This function allocates an inode identifier from the local cluster inum allocator.
	320	* The inum respects a fixed format:
	321	* - the 16 MSB bits contain the cluster identifier : cxy
	322	* - the 16 LSB bits contains the local inode identifier : lid
	323	******************************************************************************************
	324	* @ ctx : local pointer on file system context.
	325	* @ inum : [ou] buffer for allocated inode identifier.
	326	* @ return 0 if success / return non-zero if error.
	327	*****************************************************************************************/
	328	error_t vfs_ctx_inum_alloc( vfs_ctx_t * ctx,
	329	uint32_t * inum );
	330
	331	/******************************************************************************************
	332	* This function release an inode identifier.
	333	******************************************************************************************
	334	* @ ctx : local pointer on file system context.
	335	* @ inum : released inode identifier.
	336	*****************************************************************************************/
	337	void vfs_ctx_inum_release( vfs_ctx_t * ctx,
	338	uint32_t inum );
	339
	340
	341
	342
	343	/*****************************************************************************************/
	344	/******************* Inode related functions *****************************************/
	345	/*****************************************************************************************/
	346
	347	/******************************************************************************************
	348	* This function allocates memory from local cluster for an inode descriptor and the
	349	* associated mapper. It initialise these descriptors from arguments values.
	350	* The parent dentry must have been previously created.
	351	* If the client thread is not running in the cluster containing this inode,
	352	* it must use the rpc_vfs_inode_create_client() function.
	353	******************************************************************************************
	354	* @ dentry_xp : extended pointer on associated dentry (in parent inode cluster).
[23]	355	* @ fs_type : file system type.
	356	* @ inode_type : inode type.
[1]	357	* @ attr : inode attributes.
[23]	358	* @ rights : inode access rights.
[1]	359	* @ uid : user owner ID.
	360	* @ gid : group owner ID.
	361	* @ inode_xp : [out] buffer for extended pointer on created inode.
	362	* # return 0 if success / return ENOMEM or EINVAL if error.
	363	*****************************************************************************************/
[23]	364	error_t vfs_inode_create( xptr_t dentry_xp,
	365	vfs_fs_type_t fs_type,
	366	vfs_inode_type_t inode_type,
	367	uint32_t attr,
	368	uint32_t rights,
	369	uid_t uid,
	370	gid_t gid,
	371	xptr_t * inode_xp );
[1]	372
	373	/******************************************************************************************
	374	* This function releases memory allocated to an inode descriptor.
	375	* It must be executed by a thread running in the cluster containing the inode,
	376	* and the inode refcount must be zero.
	377	* If the client thread is not running in the owner cluster, it must use the
	378	* rpc_vfs_inode_destroy_client() function.
	379	******************************************************************************************
	380	* @ inode : local pointer on inode descriptor.
	381	*****************************************************************************************/
	382	void vfs_inode_destroy( vfs_inode_t * inode );
	383
	384	/******************************************************************************************
[23]	385	* This function atomically increment/decrement the inode refcount.
[1]	386	* It can be called by any thread running in any cluster.
	387	*****************************************************************************************/
	388	void vfs_inode_remote_up( xptr_t inode_xp );
	389	void vfs_inode_remote_down( xptr_t inode_xp );
	390
	391	/******************************************************************************************
	392	* This function returns the <size> of a file/dir from a remote inode,
	393	* taking the remote_rwlock protecting <size> in READ_MODE.
	394	*****************************************************************************************
	395	* @ inode_xp : extended pointer on the remote inode.
	396	* @ return the current size.
	397	*****************************************************************************************/
	398	uint32_t vfs_inode_get_size( xptr_t inode_xp );
	399
	400	/******************************************************************************************
	401	* This function set the <size> of a file/dir to a remote inode,
	402	* taking the remote_rwlock protecting <size> in WRITE_MODE.
	403	*****************************************************************************************
	404	* @ inode_xp : extended pointer on the remote inode.
	405	* @ size : value to be written.
	406	*****************************************************************************************/
	407	void vfs_inode_set_size( xptr_t inode_xp,
	408	uint32_t size );
	409
	410	/******************************************************************************************
	411	* This function takes the main lock of a remote inode.
	412	* This lock protect all inode fiels, including the children dentries.
	413	*****************************************************************************************
	414	* @ inode_xp : extended pointer on the remote inode.
	415	*****************************************************************************************/
	416	void vfs_inode_remote_lock( xptr_t inode_xp );
	417
	418	/******************************************************************************************
	419	* This function releases the main lock of a remote inode.
	420	* This lock protect all inode fiels, including the children dentries.
	421	*****************************************************************************************
	422	* @ inode_xp : extended pointer on the remote inode.
	423	*****************************************************************************************/
	424	void vfs_inode_remote_unlock( xptr_t inode_xp );
	425
	426
	427
	428
	429	/******************************************************************************************
	430	* This function TODO
	431	*****************************************************************************************/
	432	error_t vfs_inode_hold( vfs_inode_t * inode,
	433	uint32_t gc );
	434
	435	/******************************************************************************************
	436	* This function TODO
	437	*****************************************************************************************/
	438	error_t vfs_inode_trunc( vfs_inode_t * inode );
	439
	440	/******************************************************************************************
	441	* This function TODO
	442	*****************************************************************************************/
	443	error_t vfs_inode_link( vfs_inode_t * inode,
	444	uint32_t igc );
	445
	446	/******************************************************************************************
	447	* This function TODO
	448	*****************************************************************************************/
	449	error_t vfs_inode_unlink( vfs_inode_t * inode );
	450
	451	/******************************************************************************************
	452	* This function TODO
	453	*****************************************************************************************/
	454	error_t vfs_inode_stat( vfs_inode_t * inode,
	455	uint32_t inum );
	456
	457	/******************************************************************************************
	458	* This function TODO
	459	*****************************************************************************************/
	460	error_t vfs_icache_del( vfs_inode_t * inode );
	461
	462
	463	/******************************************************************************************
	464	* This function TODO Pourquoi 2 arguments ?
	465	*****************************************************************************************/
	466	error_t vfs_stat_inode( vfs_inode_t * inode,
	467	uint32_t inum );
	468
	469
	470	/*****************************************************************************************/
	471	/*************** Dentry related functions ********************************************/
	472	/*****************************************************************************************/
	473
	474	/******************************************************************************************
	475	* This function allocates memory from local cluster for a dentry descriptor,
	476	* initialises it from arguments values, and returns the extended pointer on dentry.
	477	* The inode field is not initialized, because the inode does not exist yet.
	478	* If the client thread is not running in the target cluster for this inode,
	479	* it must use the rpc_dentry_create_client() function.
	480	******************************************************************************************
[23]	481	* @ fs_type : file system type.
[1]	482	* @ name : directory entry file/dir name.
	483	* @ parent : local pointer on parent inode.
[23]	484	* @ dentry_xp : [out] buffer for extended pointer on created dentry.
[1]	485	* @ return 0 if success / return ENOMEM or EINVAL if error.
	486	*****************************************************************************************/
[23]	487	error_t vfs_dentry_create( vfs_fs_type_t fs_type,
	488	char * name,
	489	vfs_inode_t * parent,
	490	xptr_t * dentry_xp );
[1]	491
	492	/******************************************************************************************
	493	* This function releases memory allocated to a dentry descriptor.
	494	* It must be executed by a thread running in the cluster containing the dentry,
	495	* and the dentry refcount must be zero.
	496	* If the client thread is not running in the owner cluster, it must use the
	497	* rpc_dentry_destroy_client() function.
	498	******************************************************************************************
	499	* @ dentry : local pointer on dentry descriptor.
	500	*****************************************************************************************/
	501	void vfs_dentry_destroy( vfs_dentry_t * dentry );
	502
	503	/******************************************************************************************
[23]	504	* These functions atomically increment/decrement the dentry refcount.
[1]	505	* It can be called by any thread running in any cluster.
	506	*****************************************************************************************/
	507	void vfs_dentry_remote_up( xptr_t dentry_xp );
[23]	508	void vfs_dentry_remote_down( xptr_t dentry_xp );
[1]	509
[23]	510
	511	/*****************************************************************************************/
	512	/********************** File descriptor related functions ****************************/
	513	/*****************************************************************************************/
	514
[1]	515	/******************************************************************************************
[23]	516	* This function allocates memory and initializes a new local file descriptor.
	517	* It must be executed in the cluster containing the inode.
	518	* If the client thread is not running in the owner cluster, it must use the
	519	* rpc_vfs_file_create_client() function.
	520	******************************************************************************************
	521	* @ inode : local pointer on associated inode.
	522	* @ attr : file descriptor attributes.
	523	* @ file_xp : [out] buffer for extended pointer on created file descriptor.
	524	* @ return 0 if success / return ENOMEM if error.
[1]	525	*****************************************************************************************/
[23]	526	error_t vfs_file_create( vfs_inode_t * inode,
	527	uint32_t attr,
	528	xptr_t * file_xp );
[1]	529
[23]	530	/******************************************************************************************
	531	* This function releases memory allocated to a local file descriptor.
	532	* It must be executed by a thread running in the cluster containing the inode,
	533	* and the file refcount must be zero.
	534	* If the client thread is not running in the owner cluster, it must use the
	535	* rpc_vfs_file_destroy_client() function.
	536	******************************************************************************************
	537	* @ file : local pointer on file descriptor.
	538	*****************************************************************************************/
	539	void vfs_file_destroy( vfs_file_t * file );
[1]	540
[23]	541	/******************************************************************************************
	542	* These functions increment (resp. decrement) the count field in a remote file
	543	* descriptor, using a remote_atomic access.
	544	*****************************************************************************************/
	545	void vfs_file_count_up ( xptr_t file_xp );
	546	void vfs_file_count_down( xptr_t file_xp );
	547
	548
	549
[1]	550	/*****************************************************************************************/
[23]	551	/***************** Inode-Tree related functions **************************************/
[1]	552	/*****************************************************************************************/
	553
	554	/******************************************************************************************
	555	* This function returns in a kernel buffer allocated by the caller function,
	556	* the pathname of a file/dir identified by an extended pointer on the inode.
	557	* It traverse the Inode Tree from the target node to the root.
	558	* It can be called by any thread running in any cluster.
	559	******************************************************************************************
	560	* @ inode_xp : pointer on inode descriptor.
	561	* @ buffer : kernel buffer for pathname (must be allocated by caller).
	562	* @ size : max number of characters in buffer.
	563	* @ return 0 if success / return EINVAL if buffer too small.
	564	*****************************************************************************************/
	565	error_t vfs_get_path( xptr_t inode_xp,
	566	char * buffer,
	567	uint32_t max_size );
	568
	569	/******************************************************************************************
	570	* This function takes a pathname (absolute or relative to cwd) and returns an extended
[23]	571	* pointer on the associated inode.
	572	* - If a given name in the path is not found in the inode tree, it try to load the missing
	573	* dentry/inode couple, from informations found in the parent directory.
	574	* - If this directory entry does not exist on device, it returns an error.
	575	* - If the the file identified by the pathname does not exist on device but the
	576	* flag CREATE is set, the inode is created.
	577	* - If the the file identified by the pathname exist on device but both flags EXCL
	578	* and CREATE are set, an error is returned.
[1]	579	******************************************************************************************
[23]	580	* @ cwd_xp : extended pointer on current directory (for relative path).
	581	* @ pathname : path in kernel space (can be relative or absolute).
	582	* @ lookup_mode : flags defining the working mode (defined above in this file).
	583	* @ inode_xp : [out] buffer for extended pointer on inode.
	584	* @ return 0 if success / ENOENT if inode not found , EACCES if permissopn denied,
	585	* EAGAIN if a new complete lookup must be made
[1]	586	*****************************************************************************************/
[23]	587	error_t vfs_lookup( xptr_t cwd_xp,
	588	char * pathname,
	589	uint32_t lookup_mode,
	590	xptr_t * inode_xp );
[1]	591
	592	/******************************************************************************************
	593	* This function creates a new couple dentry/inode, and insert it in the Inode-Tree.
	594	* It can be executed by any thread running in any cluster, as this function
	595	* uses the rpc_dentry_create_client() and rpc_inode_create client() if required.
	596	* - The dentry is created in the cluster containing the existing <parent_xp> inode.
	597	* - the child inode and its associated mapper are created in a randomly selected cluster.
[23]	598	* - The new dentry name is defined by the <name> argument.
	599	* - The new inode and the parent inode can have different FS types.
[1]	600	******************************************************************************************
[23]	601	* @ inode_type : new inode type
	602	* @ fs_type : new inode FS type.
[1]	603	* @ parent_xp : extended pointer on parent inode.
	604	* @ name : new directory entry name.
	605	* @ child_xp : [out] buffer for extended pointer on child inode.
	606	* @ return 0 if success / ENOENT if entry not found in parent directory
	607	*****************************************************************************************/
[23]	608	error_t vfs_add_child_in_parent( vfs_inode_type_t inode_type,
	609	vfs_fs_type_t fs_type,
	610	xptr_t parent_xp,
	611	char * name,
	612	xptr_t * child_xp );
[1]	613
	614	/******************************************************************************************
[23]	615	* This function removes a couple dentry/inode from the Inode-Tree, and remove it from
	616	* the external device.
	617	* TODO
[1]	618	******************************************************************************************
	619	* @ child_xp : extended pointer on removed inode.
	620	*****************************************************************************************/
	621	error_t vfs_remove_child_from_parent( xptr_t child_xp );
	622
[23]	623
	624
	625
	626
	627
[1]	628	/*****************************************************************************************/
[23]	629	/**************** File access API ****************************************************/
[1]	630	/*****************************************************************************************/
	631
	632	/******************************************************************************************
	633	* This function allocates a vfs_file_t structure in the cluster containing the inode
[23]	634	* associated to the file identified by <cwd_xp> & <path>.
	635	* It initializes it, register it in the reference process fd_array, and returns both
	636	* the extended pointer on the remote file descriptor, and the index in the fd_array.
[1]	637	* The pathname can be relative to current directory or absolute.
[23]	638	* If the inode does not exist in the inode cache, it try to find the file on the mounted
[1]	639	* device, and creates an inode on a pseudo randomly selected cluster if found.
	640	* It the requested file does not exist on device, it creates a new inode if the
	641	* O_CREAT flag is set and return an error otherwise.
	642	******************************************************************************************
[23]	643	* @ cwd_xp : extended pointer on current working directory file descriptor.
	644	* @ path : file pathname (absolute or relative to current directory).
	645	* @ flags : defined above
	646	* @ mode : access rights (as defined by chmod)
	647	* @ file_xp : [out] buffer for extended pointer on created remote file descriptor.
	648	* @ file_id : [out] buffer for created file descriptor index in reference fd_array.
[1]	649	* @ return 0 if success / return non-zero if error.
	650	*****************************************************************************************/
	651	error_t vfs_open( xptr_t cwd_xp,
	652	char * path,
	653	uint32_t flags,
[23]	654	uint32_t mode,
	655	xptr_t * file_xp,
	656	uint32_t * file_id );
[1]	657
	658	/******************************************************************************************
[23]	659	* This function moves <size> bytes between the file identified by the open file descriptor
	660	* <file_xp> and a local kernel <buffer> , taken into account the offset in <file_xp>.
	661	* The transfer direction is defined by the <to_buffer> argument.
	662	******************************************************************************************
	663	* @ to_buffer : mapper -> buffer if true / buffer->mapper if false.
	664	* @ file_xp : extended pointer on the remote file descriptor.
	665	* @ buffer : local pointer on local kernel buffer.
[1]	666	* @ size : requested number of bytes from offset.
	667	* @ returns number of bytes actually transfered / -1 if error.
	668	*****************************************************************************************/
[23]	669	error_t vfs_move( bool_t to_buffer,
	670	xptr_t file_xp,
	671	void * buffer,
	672	uint32_t size );
[1]	673
	674	/******************************************************************************************
	675	* This function set a new value in the offset of the open file descriptor <file_xp>.
	676	* This value depends on the <whence> argument:
	677	* - if VFS_SEEK_SET, new value is <offset>
	678	* - if VFS_SEEK_CUR, new value is current_offset + <offset>
	679	* - if VFS_SEEK_END, new value is file_size + <offset>
	680	******************************************************************************************
	681	* @ file_xp : extended pointer on the remote open file descriptor.
	682	* @ offset : local pointer on source kernel buffer.
	683	* @ whence : VFS_SEEK_SET / VFS_SEEK_CUR / VFS_SEEK_END.
	684	* @ new_offset : [out] buffer for new offset value.
	685	* @ returns 0 if success / -1 if error.
	686	*****************************************************************************************/
	687	error_t vfs_lseek( xptr_t file_xp,
	688	uint32_t offset,
	689	uint32_t whence,
	690	uint32_t * new_offset );
	691
	692	/******************************************************************************************
[23]	693	* This function close an open file descriptor:
	694	* 1) All entries in fd_array copies are directly cancelled by the calling thread,
	695	* using remote accesses.
	696	* 2) The memory allocated to file descriptor in cluster containing the inode is released.
	697	* It requires a RPC if cluster containing the file descriptor is remote.
[1]	698	******************************************************************************************
	699	* @ file_xp : extended pointer on the file descriptor.
[23]	700	* @ file_id : file descriptor index in fd_array.
	701	* @ returns 0 if success / -1 if error.
[1]	702	*****************************************************************************************/
[23]	703	error_t vfs_close( xptr_t file_xp,
	704	uint32_t file_id );
[1]	705
	706	/******************************************************************************************
[23]	707	* This function remove from the file system a directory entry identified by the
	708	* <cwd_xp> & <path> arguments.
[1]	709	******************************************************************************************
[23]	710	* @ cwd_xp : extended pointer on the current working directory file descriptor.
[1]	711	* @ path : pathname (absolute or relative to current directory).
[23]	712	* @ returns 0 if success / -1 if error.
[1]	713	*****************************************************************************************/
	714	error_t vfs_unlink( xptr_t cwd_xp,
	715	char * path );
	716
	717	/******************************************************************************************
[23]	718	* This function returns, in the structure pointed by the <k_stat> kernel pointer,
	719	* various informations on the file descriptor identified by the <file_xp> argument.
	720	* TODO not implemented yet...
	721	******************************************************************************************
	722	* @ file_xp : extended pointer on the file descriptor of the searched directory .
	723	* @ k_dirent : local pointer on the dirent_t structure in kernel space.
	724	* @ returns 0 if success / -1 if error.
[1]	725	*****************************************************************************************/
	726	error_t vfs_stat( xptr_t file_xp,
[23]	727	vfs_stat_t * k_stat );
[1]	728
	729	/******************************************************************************************
[23]	730	* This function returns, in the structure pointed by the <k_dirent> kernel pointer,
	731	* various infos on the directory entry currently pointed by the <file_xp> file descriptor.
	732	* TODO not implemented yet...
	733	******************************************************************************************
	734	* @ file_xp : extended pointer on the file descriptor of the searched directory .
	735	* @ k_dirent : local pointer on the dirent_t structure in kernel space.
	736	* @ returns 0 if success / -1 if error.
[1]	737	*****************************************************************************************/
[23]	738	error_t vfs_readdir( xptr_t file_xp,
	739	vfs_dirent_t * k_dirent );
[1]	740
	741	/******************************************************************************************
[23]	742	* This function creates a new inode and associated dentry for the directory defined
	743	* by the <cwd_xp> & <path> arguments.
	744	* TODO not implemented yet...
	745	******************************************************************************************
	746	* @ cwd_xp : extended pointer on the current working directory file descriptor.
	747	* @ path : pathname (absolute or relative to current directory).
	748	* @ mode : access rights (as defined by chmod)
	749	* @ returns 0 if success / -1 if error.
[1]	750	*****************************************************************************************/
[23]	751	error_t vfs_mkdir( xptr_t cwd_xp,
	752	char * path,
	753	uint32_t mode );
[1]	754
	755	/******************************************************************************************
[23]	756	* This function remove a directory identified by the <cwd_xp / path> arguments
	757	* from the file system.
	758	* TODO not implemented yet...
	759	******************************************************************************************
	760	* @ cwd_xp : extended pointer on the current working directory file descriptor.
	761	* @ path : pathname (absolute or relative to current directory).
	762	* @ returns 0 if success / -1 if error.
[1]	763	*****************************************************************************************/
[23]	764	error_t vfs_rmdir( xptr_t cwd_xp,
	765	char * path );
[1]	766
	767	/******************************************************************************************
[23]	768	* This function makes the directory identified by <cwd_xp / path> arguments to become
	769	* the working directory for the calling process.
	770	******************************************************************************************
	771	* @ cwd_xp : extended pointer on current directory file descriptor (relative path).
	772	* @ path : file pathname (absolute or relative to current directory).
	773	* return 0 if success / -1 if error.
[1]	774	*****************************************************************************************/
[23]	775	error_t vfs_chdir( xptr_t cwd_xp,
	776	char * path );
[1]	777
	778	/******************************************************************************************
[23]	779	* This function change the access rigths for the file identified by the <cwd_xp / path>
	780	* arguments. The new access rights are defined by the <mode> argument value.
	781	******************************************************************************************
	782	* @ cwd_xp : extended pointer on current directory file descriptor (relative path).
	783	* @ path : file pathname (absolute or relative to current directory).
	784	* @ mode : access rights new value.
	785	* return 0 if success / -1 if error.
[1]	786	*****************************************************************************************/
[23]	787	error_t vfs_chmod( xptr_t cwd_xp,
	788	char * path,
	789	uint32_t mode );
[1]	790
	791	/******************************************************************************************
[23]	792	* This function creates a named FIFO file.
	793	* TODO not implemented yet
	794	******************************************************************************************
	795	* @ path : FIFO pathname (absolute or relative to current directory).
	796	* @ cwd_xp : extended pointer on the current working directory file descriptor.
	797	* @ mode : access rights new value.
[1]	798	*****************************************************************************************/
[23]	799	error_t vfs_mkfifo( xptr_t cwd_xp,
	800	char * path,
	801	uint32_t mode );
[1]	802
	803
	804	/*****************************************************************************************/
[23]	805	/**************** Mapper access API **************************************************/
[1]	806	/*****************************************************************************************/
	807
[23]	808	/******************************************************************************************
	809	* This function makes an I/O operation to move one page from VFS to a given mapper,
	810	* in case of MISS on the mapper cache.
	811	* Depending on the file system type, it calls the proper, FS specific function.
	812	* It must be executed by a thread running in the cluster containing the mapper.
	813	* The mapper pointer is obtained from the page descriptor.
	814	* It takes the mapper lock before launching the IO operation.
	815	******************************************************************************************
	816	* @ page : local pointer on the page descriptor.
	817	* @ returns 0 if success / return EINVAL if it cannot access the external device.
[1]	818	*****************************************************************************************/
[23]	819	error_t vfs_move_page_to_mapper( struct page_s * page );
[1]	820
[23]	821	/******************************************************************************************
	822	* This function makes an I/0 operation to move one page from a given mapper to VFS,
	823	* when a dirty page in the mapper cache must be updated in the File System.
	824	* Depending on the file system type, it calls the proper, FS specific function.
	825	* It must be executed by a thread running in the cluster containing the mapper.
	826	* The mapper pointer is obtained from the page descriptor.
	827	* It takes the mapper lock before launching the IO operation.
	828	* It does nothing if the page is not dirty. If the page is dirty, it clear the page
	829	* dirty bit, and remove the page from the PPM dirty list.
	830	******************************************************************************************
	831	* @ page : local pointer on the page descriptor.
	832	* @ returns 0 if success / return EINVAL if it cannot access the external device.
[1]	833	*****************************************************************************************/
[23]	834	error_t vfs_move_page_from_mapper( struct page_s * page );
[1]	835
	836
	837
	838
[23]	839
	840
	841	///////////////////////////////////////////////////////////////////////////////////////////
	842	// These typedef define the FS specific operations that must be implemented by any
	843	// specific file system to be supported by the ALMOS_MKH VFS.
	844	// These typedef are not actually used, and are only defined for documentation
	845	///////////////////////////////////////////////////////////////////////////////////////////
	846
	847	typedef error_t (fs_init_t) ( xptr_t vfs_root_xp );
	848
	849	typedef error_t (fs_inode_extend_t) ( struct vfs_inode_s * inode,
	850	void * extend );
	851
	852	typedef void (fs_inode_release_t) ( struct vfs_inode_s * inode );
	853
	854	typedef error_t (fs_write_page_t) ( struct page_s * page );
	855
	856	typedef error_t (fs_read_page_t) ( struct page_s * page );
	857
	858
	859
	860
	861
	862
	863
	864
	865	/* deprecated [AG]
	866
	867	typedef error_t (lookup_inode_t) ( vfs_inode_t * parent ,
	868	vfs_dentry_t * dentry );
	869
	870	typedef error_t (write_inode_t) ( vfs_inode_t * inode );
	871
	872	typedef error_t (release_inode_t) ( vfs_inode_t * inode );
	873
	874	typedef error_t (unlink_inode_t) ( vfs_inode_t * parent,
	875	vfs_dentry_t * dentry,
	876	uint32_t flags );
	877
	878	typedef error_t (stat_inode_t) ( vfs_inode_t * inode );
	879
	880	typedef error_t (trunc_inode_t) ( vfs_inode_t * inode );
	881
	882	typedef error_t (delete_inode_t) ( vfs_inode_t * inode );
	883
	884	typedef struct vfs_inode_op_s
	885	{
	886	init_inode_t * init;
	887	create_inode_t * create;
	888	lookup_inode_t * lookup;
	889	write_inode_t * write;
	890	release_inode_t * release;
	891	unlink_inode_t * unlink;
	892	delete_inode_t * delete;
	893	stat_inode_t * stat;
	894	trunc_inode_t * trunc; // change the size of a file
	895	}
	896	vfs_inode_op_t;
	897
	898	******************************************************************************************
	899	* These typedef define the set of FS specific operations on a VFS DENTRY descriptor.
	900	* They must be implemented by any specific file system to be supported by ALMOS_MKH.
	901	* This code is not actually used, and is only defined for documentation
	902	******************************************************************************************
	903
	904
	905	typedef error_t (vfs_compare_dentry_t) ( char * first , char * second );
	906
	907	typedef struct vfs_dentry_op_s
	908	{
	909	vfs_compare_dentry_t * compare;
	910	}
	911	vfs_dentry_op_t;
	912
	913
	914	******************************************************************************************
	915	* These typedef define the set of FS specific operations on FILE descriptors
	916	* They must be implemented by any specific file system to be supported by ALMOS_MKH.
	917	* This code is not actually used, and is only defined for documentation
	918	******************************************************************************************
	919
	920
	921	typedef error_t (open_file_t ) ( vfs_file_t * file,
	922	void * extend );
	923
	924	typedef error_t (read_file_t ) ( vfs_file_t * file,
	925	char * buffer,
	926	uint32_t count );
	927
	928	typedef error_t (write_file_t ) ( vfs_file_t * file,
	929	char * buffer,
	930	uint32_t count );
	931
	932	typedef error_t (lseek_file_t ) ( vfs_file_t * file );
	933
	934	typedef error_t (close_file_t ) ( vfs_file_t * file );
	935
	936	typedef error_t (release_file_t) ( vfs_file_t * file );
	937
	938	typedef error_t (read_dir_t ) ( vfs_file_t * file );
	939
	940	typedef error_t (mmap_file_t ) ( vfs_file_t * file ,
	941	struct vseg_s * vseg );
	942
	943	typedef error_t (munmap_file_t ) ( vfs_file_t * file,
	944	struct vseg_s * vseg );
	945
	946	typedef struct vfs_file_op_s
	947	{
	948	open_file_t * open;
	949	read_file_t * read;
	950	write_file_t * write;
	951	lseek_file_t * lseek;
	952	read_dir_t * readdir;
	953	close_file_t * close;
	954	release_file_t * release;
	955	mmap_file_t * mmap;
	956	munmap_file_t * munmap;
	957	}
	958	vfs_file_op_t;
	959
	960	*/
	961
[1]	962	#endif /* _VFS_H_ */

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