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source: trunk/kernel/fs/vfs.h @ 576

Last change on this file since 576 was 568, checked in by alain, 6 years ago
omplete restructuration of kernel locks.
File size: 46.0 KB

Rev	Line
[1]	1	/*
	2	* vfs.h - Virtual File System definition.
	3	*
[23]	4	* Author Mohamed Lamine Karaoui (2014,2015)
[437]	5	* Alain Greiner (2016,2017,2018)
[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>
[457]	29	#include <hal_kernel_types.h>
[1]	30	#include <hal_atomic.h>
	31	#include <remote_rwlock.h>
[568]	32	#include <remote_busylock.h>
	33	#include <busylock.h>
[1]	34	#include <list.h>
	35	#include <xlist.h>
	36	#include <bits.h>
	37	#include <xhtab.h>
	38	#include <errno.h>
[407]	39	#include <shared_syscalls.h>
[1]	40	#include <fatfs.h>
	41	#include <ramfs.h>
[23]	42	#include <devfs.h>
[1]	43
	44	/** Forward declarations */
	45
	46	struct vfs_inode_s;
	47	struct vfs_dentry_t;
	48	struct vfs_ctx_t;
	49	struct vfs_file_ref_s;
	50	struct vfs_file_s;
	51
	52	struct vfs_inode_op_s;
	53	struct vfs_dentry_op_s;
	54	struct vfs_file_op_s;
	55	struct vfs_ctx_op_s;
	56
	57	struct vfs_lookup_cmd_s;
	58	struct vfs_lookup_rsp_s;
	59
	60	struct mapper_s;
	61	struct process_s;
	62	struct device_s;
	63	struct vseg_s;
[23]	64	struct page_s;
[1]	65
	66
[23]	67	/******************************************************************************************
	68	* These flags are used to define the working mode of the vfs_lookup() function.
	69	*****************************************************************************************/
[1]	70
[23]	71	#define VFS_LOOKUP_DIR 0x01 /* the searched inode is a directory */
	72	#define VFS_LOOKUP_OPEN 0x02 /* the search is for an open/opendir */
	73	#define VFS_LOOKUP_PARENT 0x04 /* return the parent inode (not the inode itself) */
	74	#define VFS_LOOKUP_CREATE 0x10 /* file must be created if missing */
	75	#define VFS_LOOKUP_EXCL 0x20 /* file cannot previously exist */
[1]	76
[23]	77	/******************************************************************************************
	78	* This define the masks for the POSIX access rights to inodes
	79	*****************************************************************************************/
[1]	80
[23]	81	#define VFS_ISUID 0x0004000
	82	#define VFS_ISGID 0x0002000
	83	#define VFS_ISVTX 0x0001000
[1]	84
	85	#define VFS_IRWXU 0x0000700
	86	#define VFS_IRUSR 0x0000400
	87	#define VFS_IWUSR 0x0000200
	88	#define VFS_IXUSR 0x0000100
[23]	89
[1]	90	#define VFS_IRWXG 0x0000070
	91	#define VFS_IRGRP 0x0000040
	92	#define VFS_IWGRP 0x0000020
	93	#define VFS_IXGRP 0x0000010
[23]	94
[1]	95	#define VFS_IRWXO 0x0000007
	96	#define VFS_IROTH 0x0000004
	97	#define VFS_IWOTH 0x0000002
	98	#define VFS_IXOTH 0x0000001
	99
	100	#define VFS_IREAD VFS_IRUSR
	101	#define VFS_IWRITE VFS_IWUSR
	102	#define VFS_IEXEC VFS_IXUSR
	103
	104
[23]	105	/******************************************************************************************
[568]	106	* This structure defines a VFS context, that contains informations common to all inodes
	107	* and dentries for a given file system. As it is declared as a global variable in the
	108	* kdata segment, it is handled as private by each OS intance in a given cluster.
[23]	109	*****************************************************************************************/
[1]	110
[23]	111	typedef enum
	112	{
	113	FS_TYPE_DEVFS = 0,
	114	FS_TYPE_FATFS = 1,
	115	FS_TYPE_RAMFS = 2,
	116
	117	FS_TYPES_NR = 3,
	118	}
	119	vfs_fs_type_t;
[1]	120
[23]	121	typedef enum
	122	{
	123	CTX_ATTR_READ_ONLY = 0x01, /! write access prohibited /
	124	CTX_ATTR_SYNC = 0x10, /! synchronise FS on each write /
	125	}
	126	vfs_ctx_attr_t;
[1]	127
[23]	128	typedef struct vfs_ctx_s
	129	{
	130	vfs_fs_type_t type; /! File System type /
	131	uint32_t attr; /! global attributes for all files in FS /
[188]	132	uint32_t total_clusters; /! total number of clusters on device /
	133	uint32_t cluster_size; /! cluster size on device (bytes) /
	134	xptr_t vfs_root_xp; /! extended pointer on VFS root inode /
[568]	135	busylock_t lock; /! lock protecting inum allocator /
[23]	136	uint32_t bitmap[BITMAP_SIZE(CONFIG_VFS_MAX_INODES)]; /* inum allocator */
	137	void * extend; /! FS specific context extension /
	138	}
	139	vfs_ctx_t;
[1]	140
	141	/******************************************************************************************
	142	* This structure define a VFS inode.
	143	* It contains an extended pointer on the parent dentry, and (for directory only)
[568]	144	* an hash table (xhtab) registering all children dentries.
	145	* The <parent> inode is unique for a directory (no hard links for directories).
[1]	146	* For a file, the parent field points to the first dentry who created this inode.
[568]	147	* Synchronisation:
	148	* - the main_lock (remote_busylock) is used during the inode tree traversal,
	149	* or for inode modification (add/remove children).
	150	* - the data_lock (remote_rwlock) is used during read/write accesses to the data
	151	* stored in the mapper.
	152	* - the mapper lock (remote rwlock) is only used during the radix tree traversal
	153	* to return the relevant page for read/write.
[1]	154	*****************************************************************************************/
	155
[23]	156	/* this enum define the VFS inode types values */
	157
[10]	158	typedef enum
	159	{
[430]	160	INODE_TYPE_FILE = 0, /! file /
	161	INODE_TYPE_DIR = 1, /! directory /
	162	INODE_TYPE_FIFO = 2, /! POSIX named pipe /
	163	INODE_TYPE_PIPE = 3, /! POSIX anonymous pipe /
	164	INODE_TYPE_SOCK = 4, /! POSIX socket /
	165	INODE_TYPE_DEV = 5, /! device channel /
	166	INODE_TYPE_SYML = 6, /! symbolic link /
[10]	167	}
	168	vfs_inode_type_t;
	169
[23]	170	/* this enum define the VFS inode attributes values */
	171
[1]	172	typedef enum
	173	{
[23]	174	INODE_ATTR_DIRTY = 0x01, /* modified versus the value on device */
	175	INODE_ATTR_INLOAD = 0x04, /* loading from device in progress */
	176	INODE_ATTR_NEW = 0x08, /* not saved on device yet */
[1]	177	}
[10]	178	vfs_inode_attr_t;
[1]	179
	180	typedef struct vfs_inode_s
	181	{
[188]	182	struct vfs_ctx_s * ctx; /! local pointer on FS context /
	183	uint32_t gc; /! generation counter /
	184	uint32_t inum; /! inode identifier (unique in file system) /
	185	uint32_t attr; /! inode attributes (see above) /
	186	vfs_inode_type_t type; /! inode type (see above) /
	187	uint32_t size; /! number of bytes /
	188	uint32_t links; /! number of alias dentry /
	189	uid_t uid; /! user owner identifier /
	190	gid_t gid; /! group owner identifier /
	191	uint32_t rights; /! access rights /
	192	uint32_t refcount; /! reference counter (all pointers) /
	193	xptr_t parent_xp; /! extended pointer on parent dentry /
	194	xhtab_t children; /! embedded xhtab of children dentries /
	195	remote_rwlock_t data_lock; /! protect read/write to data and to size /
[568]	196	remote_busylock_t main_lock; /! protect inode tree traversal and modifs /
[188]	197	list_entry_t list; /! member of set of inodes in same cluster /
	198	xlist_entry_t wait_root; /! root of threads waiting on this inode /
	199	struct mapper_s * mapper; /! associated file cache /
	200	void * extend; /! fs_type_specific inode extension /
[1]	201	}
	202	vfs_inode_t;
	203
	204	/******************************************************************************************
	205	* This structure defines a directory entry.
	206	* A dentry contains the name of a remote file/dir, an extended pointer on the
	207	* inode representing this file/dir, and a local pointer on the inode representing
	208	* the parent directory.
	209	*****************************************************************************************/
	210
	211	typedef struct vfs_dentry_s
	212	{
[188]	213	struct vfs_ctx_s * ctx; /! local pointer on FS context /
	214	char name[CONFIG_VFS_MAX_NAME_LENGTH];
	215	uint32_t length; /! name length (bytes) /
	216	uint32_t refcount; /! reference counter (all pointers) /
	217	struct vfs_inode_s * parent; /! local pointer on parent inode /
	218	xptr_t child_xp; /! extended pointer on child inode /
	219	xlist_entry_t list; /! member of list of dentries with same key /
	220	void * extend; /! FS specific extension /
[1]	221	}
	222	vfs_dentry_t;
	223
	224	/******************************************************************************************
[23]	225	* This file structure describes an open file/directory for a given process.
[1]	226	* It is not replicated, and is dynamically allocated in the cluster that contains
	227	* the inode, when a thread makes an open() or opendir() system call.
[459]	228	* It cannot exist a file structure without an inode structure in same cluster.
[266]	229	* As the fd_array (containing extended pointers on the open file descriptors)
[23]	230	* is replicated in all process descriptors, we need a references counter.
[1]	231	*****************************************************************************************/
	232
	233	typedef enum
	234	{
[23]	235	FD_ATTR_READ_ENABLE = 0x01, /! read access possible /
	236	FD_ATTR_WRITE_ENABLE = 0x02, /! write access possible /
	237	FD_ATTR_APPEND = 0x04, /! append on each write /
	238	FD_ATTR_CLOSE_EXEC = 0x08, /! close file on exec /
	239	FD_ATTR_SYNC = 0x10, /! synchronise FS on each write /
	240	FD_ATTR_IS_DIR = 0x20, /! this is a directory /
[1]	241	}
[23]	242	vfs_file_attr_t;
[1]	243
	244	typedef struct vfs_file_s
	245	{
[23]	246	struct vfs_ctx_s * ctx; /! local pointer on FS context. /
[1]	247	uint32_t gc; /! generation counter /
[23]	248	vfs_file_attr_t attr; /! file attributes bit vector (see above) /
	249	vfs_inode_type_t type; /! same type as inode /
[1]	250	uint32_t offset; /! seek position in file /
[23]	251	uint32_t refcount; /! all pointers on this file descriptor /
	252	remote_rwlock_t lock; /! protect offset modifications /
[1]	253	struct mapper_s * mapper; /! associated file cache /
	254	struct vfs_inode_s * inode; /! local pointer on associated inode /
[23]	255	void * extend; /! FS specific extension /
[1]	256	}
	257	vfs_file_t;
	258
	259
	260	/*****************************************************************************************/
	261	/****************** VFS global functions *********************************************/
	262	/*****************************************************************************************/
	263
	264
	265	/******************************************************************************************
[23]	266	* This function mount a given file system type for a given process TODO.
[1]	267	*****************************************************************************************/
	268	error_t vfs_mount_fs_root( struct device_s * device,
	269	uint32_t fs_type,
	270	struct process_s * process );
	271
	272
	273	/*****************************************************************************************/
[188]	274	/***************** VFS Context related functions **************************************/
[1]	275	/*****************************************************************************************/
	276
	277	/******************************************************************************************
[188]	278	* This function initialise a (statically allocated) VFS context in local cluster.
	279	******************************************************************************************
	280	* @ fs_type : file system type.
	281	* @ attr : global attributes (for all files in FS.
	282	* @ total_clusters : total number of clusters on device.
	283	* @ cluster_size : cluster size on device (bytes).
	284	* @ vfs_root_xp : extended pointer on VFS root inode.
	285	* @ extend : fs_type_specific extension.
	286	*****************************************************************************************/
	287	void vfs_ctx_init( vfs_fs_type_t type,
	288	uint32_t attr,
	289	uint32_t total_clusters,
	290	uint32_t cluster_size,
	291	xptr_t vfs_root_xp,
	292	void * extend );
	293
	294	/******************************************************************************************
[1]	295	* This function allocates an inode identifier from the local cluster inum allocator.
	296	* The inum respects a fixed format:
	297	* - the 16 MSB bits contain the cluster identifier : cxy
	298	* - the 16 LSB bits contains the local inode identifier : lid
	299	******************************************************************************************
	300	* @ ctx : local pointer on file system context.
	301	* @ inum : [ou] buffer for allocated inode identifier.
	302	* @ return 0 if success / return non-zero if error.
	303	*****************************************************************************************/
	304	error_t vfs_ctx_inum_alloc( vfs_ctx_t * ctx,
	305	uint32_t * inum );
	306
	307	/******************************************************************************************
	308	* This function release an inode identifier.
	309	******************************************************************************************
	310	* @ ctx : local pointer on file system context.
	311	* @ inum : released inode identifier.
	312	*****************************************************************************************/
	313	void vfs_ctx_inum_release( vfs_ctx_t * ctx,
	314	uint32_t inum );
	315
	316
	317
	318
	319	/*****************************************************************************************/
	320	/******************* Inode related functions *****************************************/
	321	/*****************************************************************************************/
	322
	323	/******************************************************************************************
	324	* This function allocates memory from local cluster for an inode descriptor and the
	325	* associated mapper. It initialise these descriptors from arguments values.
	326	* The parent dentry must have been previously created.
	327	* If the client thread is not running in the cluster containing this inode,
	328	* it must use the rpc_vfs_inode_create_client() function.
	329	******************************************************************************************
	330	* @ dentry_xp : extended pointer on associated dentry (in parent inode cluster).
[23]	331	* @ fs_type : file system type.
	332	* @ inode_type : inode type.
[188]	333	* @ extend : local pointer on vs_type_specific extension.
[1]	334	* @ attr : inode attributes.
[23]	335	* @ rights : inode access rights.
[1]	336	* @ uid : user owner ID.
	337	* @ gid : group owner ID.
	338	* @ inode_xp : [out] buffer for extended pointer on created inode.
[459]	339	* @ return 0 if success / return ENOMEM or EINVAL if error.
[1]	340	*****************************************************************************************/
[23]	341	error_t vfs_inode_create( xptr_t dentry_xp,
	342	vfs_fs_type_t fs_type,
	343	vfs_inode_type_t inode_type,
[188]	344	void * extend,
[23]	345	uint32_t attr,
	346	uint32_t rights,
	347	uid_t uid,
	348	gid_t gid,
	349	xptr_t * inode_xp );
[1]	350
	351	/******************************************************************************************
	352	* This function releases memory allocated to an inode descriptor.
	353	* It must be executed by a thread running in the cluster containing the inode,
[459]	354	* and the inode refcount must be zero. If the client thread is not running in the owner
	355	* cluster, you must use the rpc_vfs_inode_destroy_client() function.
[1]	356	******************************************************************************************
	357	* @ inode : local pointer on inode descriptor.
[459]	358	* @ return 0 if success / return EINVAL if error.
[1]	359	*****************************************************************************************/
[459]	360	error_t vfs_inode_destroy( vfs_inode_t * inode );
[1]	361
[238]	362	/******************************************************************************************
	363	* This function scan an existing parent inode directory, identified by the <parent>
	364	* argument to find a directory entry identified by the <name> argument, and update
	365	* the remote child inode, identified by the <child_xp> argument.
	366	* Depending on the file system type, it calls the relevant, FS specific function,
	367	* to scan the directory, and set the "type", "size", and "extend" fields.
	368	* It must be called by a thread running in the cluster containing the parent inode.
	369	******************************************************************************************
	370	* @ parent : local pointer on parent inode (directory).
	371	* @ name : child name.
	372	* @ child_xp : extended pointer on remote child inode (file or directory)
	373	* @ return 0 if success / return ENOENT if not found.
	374	*****************************************************************************************/
	375	error_t vfs_inode_load( vfs_inode_t * parent,
	376	char * name,
	377	xptr_t child_xp );
	378
[1]	379	/******************************************************************************************
[23]	380	* This function atomically increment/decrement the inode refcount.
[1]	381	* It can be called by any thread running in any cluster.
	382	*****************************************************************************************/
	383	void vfs_inode_remote_up( xptr_t inode_xp );
	384	void vfs_inode_remote_down( xptr_t inode_xp );
	385
	386	/******************************************************************************************
	387	* This function returns the <size> of a file/dir from a remote inode,
	388	* taking the remote_rwlock protecting <size> in READ_MODE.
	389	*****************************************************************************************
	390	* @ inode_xp : extended pointer on the remote inode.
	391	* @ return the current size.
	392	*****************************************************************************************/
	393	uint32_t vfs_inode_get_size( xptr_t inode_xp );
	394
	395	/******************************************************************************************
	396	* This function set the <size> of a file/dir to a remote inode,
	397	* taking the remote_rwlock protecting <size> in WRITE_MODE.
	398	*****************************************************************************************
	399	* @ inode_xp : extended pointer on the remote inode.
	400	* @ size : value to be written.
	401	*****************************************************************************************/
	402	void vfs_inode_set_size( xptr_t inode_xp,
	403	uint32_t size );
	404
	405	/******************************************************************************************
	406	* This function takes the main lock of a remote inode.
	407	* This lock protect all inode fiels, including the children dentries.
	408	*****************************************************************************************
	409	* @ inode_xp : extended pointer on the remote inode.
	410	*****************************************************************************************/
[101]	411	void vfs_inode_lock( xptr_t inode_xp );
[1]	412
	413	/******************************************************************************************
	414	* This function releases the main lock of a remote inode.
	415	* This lock protect all inode fiels, including the children dentries.
	416	*****************************************************************************************
	417	* @ inode_xp : extended pointer on the remote inode.
	418	*****************************************************************************************/
[101]	419	void vfs_inode_unlock( xptr_t inode_xp );
[1]	420
	421	/******************************************************************************************
[409]	422	* This debug function copies the name of a remote inode identified by the <inode_xp>
	423	* argument to a local buffer identified by the <name> argument.
	424	* The local buffer size must be at least CONFIG_VFS_MAX_NAME_LENGTH.
[101]	425	*****************************************************************************************
	426	* @ inode_xp : extended pointer on the remote inode.
[409]	427	* @ name : local buffer pointer.
[1]	428	*****************************************************************************************/
[409]	429	void vfs_inode_get_name( xptr_t inode_xp,
	430	char * name );
[1]	431
[204]	432
[1]	433	/*****************************************************************************************/
	434	/*************** Dentry related functions ********************************************/
	435	/*****************************************************************************************/
	436
	437	/******************************************************************************************
	438	* This function allocates memory from local cluster for a dentry descriptor,
	439	* initialises it from arguments values, and returns the extended pointer on dentry.
	440	* The inode field is not initialized, because the inode does not exist yet.
	441	* If the client thread is not running in the target cluster for this inode,
	442	* it must use the rpc_dentry_create_client() function.
	443	******************************************************************************************
[23]	444	* @ fs_type : file system type.
[1]	445	* @ name : directory entry file/dir name.
	446	* @ parent : local pointer on parent inode.
[23]	447	* @ dentry_xp : [out] buffer for extended pointer on created dentry.
[1]	448	* @ return 0 if success / return ENOMEM or EINVAL if error.
	449	*****************************************************************************************/
[23]	450	error_t vfs_dentry_create( vfs_fs_type_t fs_type,
	451	char * name,
	452	vfs_inode_t * parent,
	453	xptr_t * dentry_xp );
[1]	454
	455	/******************************************************************************************
	456	* This function releases memory allocated to a dentry descriptor.
	457	* It must be executed by a thread running in the cluster containing the dentry,
[459]	458	* and the dentry refcount must be zero. If the client thread is not running in the owner
	459	* cluster, you must use the rpc_dentry_destroy_client() function.
[1]	460	******************************************************************************************
	461	* @ dentry : local pointer on dentry descriptor.
[459]	462	* @ return 0 if success / return EINVAL if error.
[1]	463	*****************************************************************************************/
[459]	464	error_t vfs_dentry_destroy( vfs_dentry_t * dentry );
[1]	465
	466	/******************************************************************************************
[23]	467	* These functions atomically increment/decrement the dentry refcount.
[1]	468	* It can be called by any thread running in any cluster.
	469	*****************************************************************************************/
	470	void vfs_dentry_remote_up( xptr_t dentry_xp );
[23]	471	void vfs_dentry_remote_down( xptr_t dentry_xp );
[1]	472
[23]	473
	474	/*****************************************************************************************/
	475	/********************** File descriptor related functions ****************************/
	476	/*****************************************************************************************/
	477
[1]	478	/******************************************************************************************
[23]	479	* This function allocates memory and initializes a new local file descriptor.
	480	* It must be executed in the cluster containing the inode.
	481	* If the client thread is not running in the owner cluster, it must use the
	482	* rpc_vfs_file_create_client() function.
	483	******************************************************************************************
	484	* @ inode : local pointer on associated inode.
	485	* @ attr : file descriptor attributes.
	486	* @ file_xp : [out] buffer for extended pointer on created file descriptor.
	487	* @ return 0 if success / return ENOMEM if error.
[1]	488	*****************************************************************************************/
[23]	489	error_t vfs_file_create( vfs_inode_t * inode,
	490	uint32_t attr,
	491	xptr_t * file_xp );
[1]	492
[23]	493	/******************************************************************************************
	494	* This function releases memory allocated to a local file descriptor.
	495	* It must be executed by a thread running in the cluster containing the inode,
	496	* and the file refcount must be zero.
	497	* If the client thread is not running in the owner cluster, it must use the
	498	* rpc_vfs_file_destroy_client() function.
	499	******************************************************************************************
	500	* @ file : local pointer on file descriptor.
	501	*****************************************************************************************/
	502	void vfs_file_destroy( vfs_file_t * file );
[1]	503
[23]	504	/******************************************************************************************
	505	* These functions increment (resp. decrement) the count field in a remote file
	506	* descriptor, using a remote_atomic access.
	507	*****************************************************************************************/
	508	void vfs_file_count_up ( xptr_t file_xp );
	509	void vfs_file_count_down( xptr_t file_xp );
	510
	511
	512
[1]	513	/*****************************************************************************************/
[23]	514	/***************** Inode-Tree related functions **************************************/
[1]	515	/*****************************************************************************************/
	516
	517	/******************************************************************************************
	518	* This function returns in a kernel buffer allocated by the caller function,
	519	* the pathname of a file/dir identified by an extended pointer on the inode.
	520	* It traverse the Inode Tree from the target node to the root.
	521	* It can be called by any thread running in any cluster.
	522	******************************************************************************************
	523	* @ inode_xp : pointer on inode descriptor.
	524	* @ buffer : kernel buffer for pathname (must be allocated by caller).
	525	* @ size : max number of characters in buffer.
	526	* @ return 0 if success / return EINVAL if buffer too small.
	527	*****************************************************************************************/
	528	error_t vfs_get_path( xptr_t inode_xp,
	529	char * buffer,
	530	uint32_t max_size );
	531
	532	/******************************************************************************************
	533	* This function takes a pathname (absolute or relative to cwd) and returns an extended
[23]	534	* pointer on the associated inode.
[459]	535	* - If a given directory name in the path is not found in the inode tree, it try to load
	536	* the missing dentry/inode couple, from informations found in the parent directory.
[23]	537	* - If this directory entry does not exist on device, it returns an error.
	538	* - If the the file identified by the pathname does not exist on device but the
	539	* flag CREATE is set, the inode is created.
	540	* - If the the file identified by the pathname exist on device but both flags EXCL
	541	* and CREATE are set, an error is returned.
[1]	542	******************************************************************************************
[23]	543	* @ cwd_xp : extended pointer on current directory (for relative path).
	544	* @ pathname : path in kernel space (can be relative or absolute).
	545	* @ lookup_mode : flags defining the working mode (defined above in this file).
[238]	546	* @ inode_xp : [out] buffer for extended pointer on searched inode.
[407]	547	* @ return 0 if success / ENOENT if inode not found , EACCES if permisson denied,
	548	* EAGAIN if a new complete lookup must be made
[1]	549	*****************************************************************************************/
[23]	550	error_t vfs_lookup( xptr_t cwd_xp,
	551	char * pathname,
	552	uint32_t lookup_mode,
	553	xptr_t * inode_xp );
[1]	554
	555	/******************************************************************************************
	556	* This function creates a new couple dentry/inode, and insert it in the Inode-Tree.
[407]	557	* It can be executed by any thread running in any cluster (can be different from both
[296]	558	* the child cluster and the parent cluster), as it uses the rpc_dentry_create_client()
	559	* and rpc_inode_create client() if required. This is done in three steps:
[204]	560	* 1) The dentry is created in the cluster containing the existing <parent_xp> inode.
	561	* The new dentry name is defined by the <name> argument.
	562	* 2) The inode and its associated mapper are created in cluster identified by <child_cxy>.
	563	* The new inode and the parent inode can have different FS types.
[238]	564	* 3) The "child_xp" field in created dentry (pointing on the created inode) is updated.
[1]	565	******************************************************************************************
[188]	566	* @ child_cxy : target cluster for child inode.
[23]	567	* @ inode_type : new inode type
	568	* @ fs_type : new inode FS type.
[1]	569	* @ parent_xp : extended pointer on parent inode.
	570	* @ name : new directory entry name.
[188]	571	* @ extend : fs_type_specific inode extension.
[1]	572	* @ child_xp : [out] buffer for extended pointer on child inode.
[204]	573	* @ return 0 if success / ENOMEM if dentry or inode cannot be created.
[1]	574	*****************************************************************************************/
[188]	575	error_t vfs_add_child_in_parent( cxy_t child_cxy,
	576	vfs_inode_type_t inode_type,
[23]	577	vfs_fs_type_t fs_type,
	578	xptr_t parent_xp,
	579	char * name,
[188]	580	void * extend,
[23]	581	xptr_t * child_xp );
[1]	582
	583	/******************************************************************************************
[23]	584	* This function removes a couple dentry/inode from the Inode-Tree, and remove it from
	585	* the external device.
[1]	586	******************************************************************************************
	587	* @ child_xp : extended pointer on removed inode.
	588	*****************************************************************************************/
[459]	589	error_t vfs_remove_child_from_parent( xptr_t inode_xp );
[1]	590
[188]	591	/******************************************************************************************
	592	* This recursive function diplays a complete inode/dentry sub-tree.
	593	* Any inode can be selected as the sub-tree root.
[238]	594	* TODO this function is not protected against a concurrent inode/dentry removal...
[188]	595	******************************************************************************************
	596	* @ inode_xp : extended pointer on sub-tree root inode.
	597	*****************************************************************************************/
	598	void vfs_display( xptr_t inode_xp );
[23]	599
	600
	601
	602
	603
[1]	604	/*****************************************************************************************/
[23]	605	/**************** File access API ****************************************************/
[1]	606	/*****************************************************************************************/
	607
	608	/******************************************************************************************
	609	* This function allocates a vfs_file_t structure in the cluster containing the inode
[407]	610	* associated to the file identified by the <cwd_xp> & <path> arguments.
	611	* It initializes it, register it in the reference process fd_array identified by the
	612	* <process> argument, and returns both the extended pointer on the file descriptor,
	613	* and the allocated index in the fd_array.
[1]	614	* The pathname can be relative to current directory or absolute.
[23]	615	* If the inode does not exist in the inode cache, it try to find the file on the mounted
[1]	616	* device, and creates an inode on a pseudo randomly selected cluster if found.
	617	* It the requested file does not exist on device, it creates a new inode if the
[407]	618	* O_CREAT flag is set, and return an error otherwise.
[1]	619	******************************************************************************************
[407]	620	* @ process : local pointer on local process descriptor copy.
[23]	621	* @ path : file pathname (absolute or relative to current directory).
[407]	622	* @ flags : defined above.
[23]	623	* @ mode : access rights (as defined by chmod)
	624	* @ file_xp : [out] buffer for extended pointer on created remote file descriptor.
	625	* @ file_id : [out] buffer for created file descriptor index in reference fd_array.
[1]	626	* @ return 0 if success / return non-zero if error.
	627	*****************************************************************************************/
[407]	628	error_t vfs_open( struct process_s * process,
	629	char * path,
	630	uint32_t flags,
	631	uint32_t mode,
	632	xptr_t * file_xp,
	633	uint32_t * file_id );
[1]	634
	635	/******************************************************************************************
[313]	636	* This function moves <size> bytes between a remote file mapper, identified by the
	637	* <file_xp> argument, and a - possibly distributed - user space <buffer>, taken into
	638	* account the offset in <file_xp>. The transfer direction is defined by <to_buffer>.
[407]	639	* It is called by the sys_read() and sys_write() functions.
[23]	640	******************************************************************************************
[265]	641	* @ to_buffer : mapper -> buffer if true / buffer -> mapper if false.
[23]	642	* @ file_xp : extended pointer on the remote file descriptor.
[313]	643	* @ buffer : user space pointer on buffer (can be physically distributed).
[1]	644	* @ size : requested number of bytes from offset.
[407]	645	* @ returns number of bytes actually moved if success / -1 if error.
[1]	646	*****************************************************************************************/
[407]	647	int vfs_user_move( bool_t to_buffer,
	648	xptr_t file_xp,
	649	void * buffer,
	650	uint32_t size );
[1]	651
	652	/******************************************************************************************
[317]	653	* This function moves <size> bytes between a remote file mapper, identified by the
	654	* <file_xp> argument, and a - possibly remote - kernel <buffer_xp>, taken into
	655	* account the offset in <file_xp>. The transfer direction is defined by <to_buffer>.
[407]	656	* It is called by the elf_load_process() function.
[317]	657	******************************************************************************************
	658	* @ to_buffer : mapper -> buffer if true / buffer -> mapper if false.
	659	* @ file_xp : extended pointer on the remote file descriptor.
	660	* @ buffer_xp : user space pointer on buffer (can be physically distributed).
	661	* @ size : requested number of bytes from offset.
[407]	662	* @ returns 0 if success / -1 if error.
[317]	663	*****************************************************************************************/
	664	error_t vfs_kernel_move( bool_t to_buffer,
	665	xptr_t file_xp,
	666	xptr_t buffer_xp,
	667	uint32_t size );
	668
	669	/******************************************************************************************
[1]	670	* This function set a new value in the offset of the open file descriptor <file_xp>.
	671	* This value depends on the <whence> argument:
	672	* - if VFS_SEEK_SET, new value is <offset>
	673	* - if VFS_SEEK_CUR, new value is current_offset + <offset>
	674	* - if VFS_SEEK_END, new value is file_size + <offset>
	675	******************************************************************************************
	676	* @ file_xp : extended pointer on the remote open file descriptor.
	677	* @ offset : local pointer on source kernel buffer.
	678	* @ whence : VFS_SEEK_SET / VFS_SEEK_CUR / VFS_SEEK_END.
	679	* @ new_offset : [out] buffer for new offset value.
	680	* @ returns 0 if success / -1 if error.
	681	*****************************************************************************************/
	682	error_t vfs_lseek( xptr_t file_xp,
	683	uint32_t offset,
	684	uint32_t whence,
	685	uint32_t * new_offset );
	686
	687	/******************************************************************************************
[459]	688	* This function close the -non-replicated- file descriptor identified by the <file_xp>
	689	* and <file_id> arguments.
	690	* 1) All entries in the fd_array copies are directly reset by the calling thread,
[23]	691	* using remote accesses.
	692	* 2) The memory allocated to file descriptor in cluster containing the inode is released.
	693	* It requires a RPC if cluster containing the file descriptor is remote.
[1]	694	******************************************************************************************
[459]	695	* @ file_xp : extended pointer on the file descriptor in owner cluster.
[23]	696	* @ file_id : file descriptor index in fd_array.
	697	* @ returns 0 if success / -1 if error.
[1]	698	*****************************************************************************************/
[23]	699	error_t vfs_close( xptr_t file_xp,
	700	uint32_t file_id );
[1]	701
	702	/******************************************************************************************
[23]	703	* This function remove from the file system a directory entry identified by the
	704	* <cwd_xp> & <path> arguments.
[1]	705	******************************************************************************************
[23]	706	* @ cwd_xp : extended pointer on the current working directory file descriptor.
[1]	707	* @ path : pathname (absolute or relative to current directory).
[23]	708	* @ returns 0 if success / -1 if error.
[1]	709	*****************************************************************************************/
	710	error_t vfs_unlink( xptr_t cwd_xp,
	711	char * path );
	712
	713	/******************************************************************************************
[23]	714	* This function returns, in the structure pointed by the <k_stat> kernel pointer,
	715	* various informations on the file descriptor identified by the <file_xp> argument.
	716	* TODO not implemented yet...
	717	******************************************************************************************
	718	* @ file_xp : extended pointer on the file descriptor of the searched directory .
[407]	719	* @ k_stat : local pointer on the stat structure in kernel space.
[23]	720	* @ returns 0 if success / -1 if error.
[1]	721	*****************************************************************************************/
[407]	722	error_t vfs_stat( xptr_t file_xp,
	723	struct stat * k_stat );
[1]	724
	725	/******************************************************************************************
[23]	726	* This function returns, in the structure pointed by the <k_dirent> kernel pointer,
	727	* various infos on the directory entry currently pointed by the <file_xp> file descriptor.
	728	* TODO not implemented yet...
	729	******************************************************************************************
	730	* @ file_xp : extended pointer on the file descriptor of the searched directory .
[407]	731	* @ k_dirent : local pointer on the dirent structure in kernel space.
[23]	732	* @ returns 0 if success / -1 if error.
[1]	733	*****************************************************************************************/
[407]	734	error_t vfs_readdir( xptr_t file_xp,
	735	struct dirent * k_dirent );
[1]	736
	737	/******************************************************************************************
[23]	738	* This function creates a new inode and associated dentry for the directory defined
	739	* by the <cwd_xp> & <path> arguments.
	740	* TODO not implemented yet...
	741	******************************************************************************************
	742	* @ cwd_xp : extended pointer on the current working directory file descriptor.
	743	* @ path : pathname (absolute or relative to current directory).
	744	* @ mode : access rights (as defined by chmod)
	745	* @ returns 0 if success / -1 if error.
[1]	746	*****************************************************************************************/
[23]	747	error_t vfs_mkdir( xptr_t cwd_xp,
	748	char * path,
	749	uint32_t mode );
[1]	750
	751	/******************************************************************************************
[23]	752	* This function remove a directory identified by the <cwd_xp / path> arguments
	753	* from the file system.
	754	* TODO not implemented yet...
	755	******************************************************************************************
	756	* @ cwd_xp : extended pointer on the current working directory file descriptor.
	757	* @ path : pathname (absolute or relative to current directory).
	758	* @ returns 0 if success / -1 if error.
[1]	759	*****************************************************************************************/
[23]	760	error_t vfs_rmdir( xptr_t cwd_xp,
	761	char * path );
[1]	762
	763	/******************************************************************************************
[23]	764	* This function makes the directory identified by <cwd_xp / path> arguments to become
	765	* the working directory for the calling process.
	766	******************************************************************************************
	767	* @ cwd_xp : extended pointer on current directory file descriptor (relative path).
	768	* @ path : file pathname (absolute or relative to current directory).
	769	* return 0 if success / -1 if error.
[1]	770	*****************************************************************************************/
[23]	771	error_t vfs_chdir( xptr_t cwd_xp,
	772	char * path );
[1]	773
	774	/******************************************************************************************
[23]	775	* This function change the access rigths for the file identified by the <cwd_xp / path>
	776	* arguments. The new access rights are defined by the <mode> argument value.
	777	******************************************************************************************
	778	* @ cwd_xp : extended pointer on current directory file descriptor (relative path).
	779	* @ path : file pathname (absolute or relative to current directory).
	780	* @ mode : access rights new value.
	781	* return 0 if success / -1 if error.
[1]	782	*****************************************************************************************/
[23]	783	error_t vfs_chmod( xptr_t cwd_xp,
	784	char * path,
	785	uint32_t mode );
[1]	786
	787	/******************************************************************************************
[23]	788	* This function creates a named FIFO file.
	789	* TODO not implemented yet
	790	******************************************************************************************
	791	* @ path : FIFO pathname (absolute or relative to current directory).
	792	* @ cwd_xp : extended pointer on the current working directory file descriptor.
	793	* @ mode : access rights new value.
[1]	794	*****************************************************************************************/
[23]	795	error_t vfs_mkfifo( xptr_t cwd_xp,
	796	char * path,
	797	uint32_t mode );
[1]	798
	799
	800	/*****************************************************************************************/
[23]	801	/**************** Mapper access API **************************************************/
[1]	802	/*****************************************************************************************/
	803
[23]	804	/******************************************************************************************
[238]	805	* This function makes an I/O operation to move one page to/from device from/to the mapper.
	806	* It is used in case of MISS on the mapper, or when a dirty page in the mapper must
	807	* be updated in the File System.
[23]	808	* Depending on the file system type, it calls the proper, FS specific function.
	809	* It must be executed by a thread running in the cluster containing the mapper.
	810	* The mapper pointer is obtained from the page descriptor.
	811	* It takes the mapper lock before launching the IO operation.
	812	******************************************************************************************
[238]	813	* @ page : local pointer on the page descriptor.
	814	* @ to_mapper : transfer direction.
[23]	815	* @ returns 0 if success / return EINVAL if it cannot access the external device.
[1]	816	*****************************************************************************************/
[238]	817	error_t vfs_mapper_move_page( struct page_s * page,
	818	bool_t to_mapper );
[1]	819
[23]	820	/******************************************************************************************
[459]	821	* This function makes the I/O operations required to move, from device to mapper,
	822	* all pages covering a given inode, identified by the <inode> argument. The target
	823	* inode can be a directory or a file, but this function is mainly used to load (prefetch)
	824	* a complete directory to the mapper.
[23]	825	* Depending on the file system type, it calls the proper, FS specific function.
	826	* It must be executed by a thread running in the cluster containing the mapper.
[238]	827	* The mapper pointer is obtained from the inode descriptor.
[23]	828	* It takes the mapper lock before launching the IO operation.
	829	******************************************************************************************
[238]	830	* @ inode : local pointer on inode.
	831	* @ return 0 if success / return EIO if device access failure.
[1]	832	*****************************************************************************************/
[238]	833	error_t vfs_mapper_load_all( vfs_inode_t * inode );
[1]	834
	835
	836	#endif /* _VFS_H_ */

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