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v6.2
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * This file contains vfs inode ops for the 9P2000 protocol.
   4 *
   5 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   6 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   7 */
   8
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/module.h>
  12#include <linux/errno.h>
  13#include <linux/fs.h>
  14#include <linux/file.h>
  15#include <linux/pagemap.h>
  16#include <linux/stat.h>
  17#include <linux/string.h>
  18#include <linux/inet.h>
  19#include <linux/namei.h>
  20#include <linux/sched.h>
  21#include <linux/slab.h>
  22#include <linux/xattr.h>
  23#include <linux/posix_acl.h>
  24#include <net/9p/9p.h>
  25#include <net/9p/client.h>
  26
  27#include "v9fs.h"
  28#include "v9fs_vfs.h"
  29#include "fid.h"
  30#include "cache.h"
  31#include "xattr.h"
  32#include "acl.h"
  33
  34static const struct inode_operations v9fs_dir_inode_operations;
  35static const struct inode_operations v9fs_dir_inode_operations_dotu;
  36static const struct inode_operations v9fs_file_inode_operations;
  37static const struct inode_operations v9fs_symlink_inode_operations;
  38
  39/**
  40 * unixmode2p9mode - convert unix mode bits to plan 9
  41 * @v9ses: v9fs session information
  42 * @mode: mode to convert
  43 *
  44 */
  45
  46static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
  47{
  48	int res;
  49
  50	res = mode & 0777;
  51	if (S_ISDIR(mode))
  52		res |= P9_DMDIR;
  53	if (v9fs_proto_dotu(v9ses)) {
  54		if (v9ses->nodev == 0) {
  55			if (S_ISSOCK(mode))
  56				res |= P9_DMSOCKET;
  57			if (S_ISFIFO(mode))
  58				res |= P9_DMNAMEDPIPE;
  59			if (S_ISBLK(mode))
  60				res |= P9_DMDEVICE;
  61			if (S_ISCHR(mode))
  62				res |= P9_DMDEVICE;
  63		}
  64
  65		if ((mode & S_ISUID) == S_ISUID)
  66			res |= P9_DMSETUID;
  67		if ((mode & S_ISGID) == S_ISGID)
  68			res |= P9_DMSETGID;
  69		if ((mode & S_ISVTX) == S_ISVTX)
  70			res |= P9_DMSETVTX;
  71	}
  72	return res;
  73}
  74
  75/**
  76 * p9mode2perm- convert plan9 mode bits to unix permission bits
  77 * @v9ses: v9fs session information
  78 * @stat: p9_wstat from which mode need to be derived
  79 *
  80 */
  81static int p9mode2perm(struct v9fs_session_info *v9ses,
  82		       struct p9_wstat *stat)
  83{
  84	int res;
  85	int mode = stat->mode;
  86
  87	res = mode & S_IALLUGO;
  88	if (v9fs_proto_dotu(v9ses)) {
  89		if ((mode & P9_DMSETUID) == P9_DMSETUID)
  90			res |= S_ISUID;
  91
  92		if ((mode & P9_DMSETGID) == P9_DMSETGID)
  93			res |= S_ISGID;
  94
  95		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
  96			res |= S_ISVTX;
  97	}
  98	return res;
  99}
 100
 101/**
 102 * p9mode2unixmode- convert plan9 mode bits to unix mode bits
 103 * @v9ses: v9fs session information
 104 * @stat: p9_wstat from which mode need to be derived
 105 * @rdev: major number, minor number in case of device files.
 106 *
 107 */
 108static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
 109			       struct p9_wstat *stat, dev_t *rdev)
 110{
 111	int res, r;
 112	u32 mode = stat->mode;
 113
 114	*rdev = 0;
 115	res = p9mode2perm(v9ses, stat);
 116
 117	if ((mode & P9_DMDIR) == P9_DMDIR)
 118		res |= S_IFDIR;
 119	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
 120		res |= S_IFLNK;
 121	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
 122		 && (v9ses->nodev == 0))
 123		res |= S_IFSOCK;
 124	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
 125		 && (v9ses->nodev == 0))
 126		res |= S_IFIFO;
 127	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 128		 && (v9ses->nodev == 0)) {
 129		char type = 0;
 130		int major = -1, minor = -1;
 131
 132		r = sscanf(stat->extension, "%c %i %i", &type, &major, &minor);
 133		if (r != 3) {
 134			p9_debug(P9_DEBUG_ERROR,
 135				 "invalid device string, umode will be bogus: %s\n",
 136				 stat->extension);
 137			return res;
 138		}
 139		switch (type) {
 140		case 'c':
 141			res |= S_IFCHR;
 142			break;
 143		case 'b':
 144			res |= S_IFBLK;
 145			break;
 146		default:
 147			p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
 148				 type, stat->extension);
 149		}
 150		*rdev = MKDEV(major, minor);
 151	} else
 152		res |= S_IFREG;
 153
 154	return res;
 155}
 156
 157/**
 158 * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 159 * @uflags: flags to convert
 160 * @extended: if .u extensions are active
 161 */
 162
 163int v9fs_uflags2omode(int uflags, int extended)
 164{
 165	int ret;
 166
 167	ret = 0;
 168	switch (uflags&3) {
 169	default:
 170	case O_RDONLY:
 171		ret = P9_OREAD;
 172		break;
 173
 174	case O_WRONLY:
 175		ret = P9_OWRITE;
 176		break;
 177
 178	case O_RDWR:
 179		ret = P9_ORDWR;
 180		break;
 181	}
 182
 
 
 
 183	if (extended) {
 184		if (uflags & O_EXCL)
 185			ret |= P9_OEXCL;
 186
 187		if (uflags & O_APPEND)
 188			ret |= P9_OAPPEND;
 189	}
 190
 191	return ret;
 192}
 193
 194/**
 195 * v9fs_blank_wstat - helper function to setup a 9P stat structure
 196 * @wstat: structure to initialize
 197 *
 198 */
 199
 200void
 201v9fs_blank_wstat(struct p9_wstat *wstat)
 202{
 203	wstat->type = ~0;
 204	wstat->dev = ~0;
 205	wstat->qid.type = ~0;
 206	wstat->qid.version = ~0;
 207	*((long long *)&wstat->qid.path) = ~0;
 208	wstat->mode = ~0;
 209	wstat->atime = ~0;
 210	wstat->mtime = ~0;
 211	wstat->length = ~0;
 212	wstat->name = NULL;
 213	wstat->uid = NULL;
 214	wstat->gid = NULL;
 215	wstat->muid = NULL;
 216	wstat->n_uid = INVALID_UID;
 217	wstat->n_gid = INVALID_GID;
 218	wstat->n_muid = INVALID_UID;
 219	wstat->extension = NULL;
 220}
 221
 222/**
 223 * v9fs_alloc_inode - helper function to allocate an inode
 224 * @sb: The superblock to allocate the inode from
 225 */
 226struct inode *v9fs_alloc_inode(struct super_block *sb)
 227{
 228	struct v9fs_inode *v9inode;
 229
 230	v9inode = alloc_inode_sb(sb, v9fs_inode_cache, GFP_KERNEL);
 231	if (!v9inode)
 232		return NULL;
 233	v9inode->writeback_fid = NULL;
 234	v9inode->cache_validity = 0;
 235	mutex_init(&v9inode->v_mutex);
 236	return &v9inode->netfs.inode;
 237}
 238
 239/**
 240 * v9fs_free_inode - destroy an inode
 241 * @inode: The inode to be freed
 242 */
 243
 244void v9fs_free_inode(struct inode *inode)
 245{
 246	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
 247}
 248
 249/*
 250 * Set parameters for the netfs library
 251 */
 252static void v9fs_set_netfs_context(struct inode *inode)
 253{
 254	struct v9fs_inode *v9inode = V9FS_I(inode);
 255	netfs_inode_init(&v9inode->netfs, &v9fs_req_ops);
 256}
 257
 258int v9fs_init_inode(struct v9fs_session_info *v9ses,
 259		    struct inode *inode, umode_t mode, dev_t rdev)
 260{
 261	int err = 0;
 262
 263	inode_init_owner(&init_user_ns, inode, NULL, mode);
 264	inode->i_blocks = 0;
 265	inode->i_rdev = rdev;
 266	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 267	inode->i_mapping->a_ops = &v9fs_addr_operations;
 268	inode->i_private = NULL;
 269
 270	switch (mode & S_IFMT) {
 271	case S_IFIFO:
 272	case S_IFBLK:
 273	case S_IFCHR:
 274	case S_IFSOCK:
 275		if (v9fs_proto_dotl(v9ses)) {
 276			inode->i_op = &v9fs_file_inode_operations_dotl;
 277		} else if (v9fs_proto_dotu(v9ses)) {
 278			inode->i_op = &v9fs_file_inode_operations;
 279		} else {
 280			p9_debug(P9_DEBUG_ERROR,
 281				 "special files without extended mode\n");
 282			err = -EINVAL;
 283			goto error;
 284		}
 285		init_special_inode(inode, inode->i_mode, inode->i_rdev);
 286		break;
 287	case S_IFREG:
 288		if (v9fs_proto_dotl(v9ses)) {
 289			inode->i_op = &v9fs_file_inode_operations_dotl;
 290			if (v9ses->cache == CACHE_LOOSE ||
 291			    v9ses->cache == CACHE_FSCACHE)
 292				inode->i_fop =
 293					&v9fs_cached_file_operations_dotl;
 294			else if (v9ses->cache == CACHE_MMAP)
 295				inode->i_fop = &v9fs_mmap_file_operations_dotl;
 296			else
 297				inode->i_fop = &v9fs_file_operations_dotl;
 298		} else {
 299			inode->i_op = &v9fs_file_inode_operations;
 300			if (v9ses->cache == CACHE_LOOSE ||
 301			    v9ses->cache == CACHE_FSCACHE)
 302				inode->i_fop =
 303					&v9fs_cached_file_operations;
 304			else if (v9ses->cache == CACHE_MMAP)
 305				inode->i_fop = &v9fs_mmap_file_operations;
 306			else
 307				inode->i_fop = &v9fs_file_operations;
 308		}
 309
 310		break;
 311	case S_IFLNK:
 312		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 313			p9_debug(P9_DEBUG_ERROR,
 314				 "extended modes used with legacy protocol\n");
 315			err = -EINVAL;
 316			goto error;
 317		}
 318
 319		if (v9fs_proto_dotl(v9ses))
 320			inode->i_op = &v9fs_symlink_inode_operations_dotl;
 321		else
 322			inode->i_op = &v9fs_symlink_inode_operations;
 323
 324		break;
 325	case S_IFDIR:
 326		inc_nlink(inode);
 327		if (v9fs_proto_dotl(v9ses))
 328			inode->i_op = &v9fs_dir_inode_operations_dotl;
 329		else if (v9fs_proto_dotu(v9ses))
 330			inode->i_op = &v9fs_dir_inode_operations_dotu;
 331		else
 332			inode->i_op = &v9fs_dir_inode_operations;
 333
 334		if (v9fs_proto_dotl(v9ses))
 335			inode->i_fop = &v9fs_dir_operations_dotl;
 336		else
 337			inode->i_fop = &v9fs_dir_operations;
 338
 339		break;
 340	default:
 341		p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
 342			 mode, mode & S_IFMT);
 343		err = -EINVAL;
 344		goto error;
 345	}
 346
 347	v9fs_set_netfs_context(inode);
 348error:
 349	return err;
 350
 351}
 352
 353/**
 354 * v9fs_get_inode - helper function to setup an inode
 355 * @sb: superblock
 356 * @mode: mode to setup inode with
 357 * @rdev: The device numbers to set
 358 */
 359
 360struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t rdev)
 361{
 362	int err;
 363	struct inode *inode;
 364	struct v9fs_session_info *v9ses = sb->s_fs_info;
 365
 366	p9_debug(P9_DEBUG_VFS, "super block: %p mode: %ho\n", sb, mode);
 367
 368	inode = new_inode(sb);
 369	if (!inode) {
 370		pr_warn("%s (%d): Problem allocating inode\n",
 371			__func__, task_pid_nr(current));
 372		return ERR_PTR(-ENOMEM);
 373	}
 374	err = v9fs_init_inode(v9ses, inode, mode, rdev);
 375	if (err) {
 376		iput(inode);
 377		return ERR_PTR(err);
 378	}
 379	return inode;
 380}
 381
 382/**
 383 * v9fs_evict_inode - Remove an inode from the inode cache
 384 * @inode: inode to release
 385 *
 386 */
 387void v9fs_evict_inode(struct inode *inode)
 388{
 389	struct v9fs_inode *v9inode = V9FS_I(inode);
 390	__le32 version;
 391
 392	truncate_inode_pages_final(&inode->i_data);
 393	version = cpu_to_le32(v9inode->qid.version);
 394	fscache_clear_inode_writeback(v9fs_inode_cookie(v9inode), inode,
 395				      &version);
 396	clear_inode(inode);
 397	filemap_fdatawrite(&inode->i_data);
 398
 399	fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
 400	/* clunk the fid stashed in writeback_fid */
 401	p9_fid_put(v9inode->writeback_fid);
 402	v9inode->writeback_fid = NULL;
 
 
 
 
 
 403}
 404
 405static int v9fs_test_inode(struct inode *inode, void *data)
 406{
 407	int umode;
 408	dev_t rdev;
 409	struct v9fs_inode *v9inode = V9FS_I(inode);
 410	struct p9_wstat *st = (struct p9_wstat *)data;
 411	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 412
 413	umode = p9mode2unixmode(v9ses, st, &rdev);
 414	/* don't match inode of different type */
 415	if (inode_wrong_type(inode, umode))
 416		return 0;
 417
 418	/* compare qid details */
 419	if (memcmp(&v9inode->qid.version,
 420		   &st->qid.version, sizeof(v9inode->qid.version)))
 421		return 0;
 422
 423	if (v9inode->qid.type != st->qid.type)
 424		return 0;
 425
 426	if (v9inode->qid.path != st->qid.path)
 427		return 0;
 428	return 1;
 429}
 430
 431static int v9fs_test_new_inode(struct inode *inode, void *data)
 432{
 433	return 0;
 434}
 435
 436static int v9fs_set_inode(struct inode *inode,  void *data)
 437{
 438	struct v9fs_inode *v9inode = V9FS_I(inode);
 439	struct p9_wstat *st = (struct p9_wstat *)data;
 440
 441	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
 442	return 0;
 443}
 444
 445static struct inode *v9fs_qid_iget(struct super_block *sb,
 446				   struct p9_qid *qid,
 447				   struct p9_wstat *st,
 448				   int new)
 449{
 450	dev_t rdev;
 451	int retval;
 452	umode_t umode;
 453	unsigned long i_ino;
 454	struct inode *inode;
 455	struct v9fs_session_info *v9ses = sb->s_fs_info;
 456	int (*test)(struct inode *inode, void *data);
 457
 458	if (new)
 459		test = v9fs_test_new_inode;
 460	else
 461		test = v9fs_test_inode;
 462
 463	i_ino = v9fs_qid2ino(qid);
 464	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
 465	if (!inode)
 466		return ERR_PTR(-ENOMEM);
 467	if (!(inode->i_state & I_NEW))
 468		return inode;
 469	/*
 470	 * initialize the inode with the stat info
 471	 * FIXME!! we may need support for stale inodes
 472	 * later.
 473	 */
 474	inode->i_ino = i_ino;
 475	umode = p9mode2unixmode(v9ses, st, &rdev);
 476	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 477	if (retval)
 478		goto error;
 479
 480	v9fs_stat2inode(st, inode, sb, 0);
 
 481	v9fs_cache_inode_get_cookie(inode);
 482	unlock_new_inode(inode);
 483	return inode;
 484error:
 485	iget_failed(inode);
 486	return ERR_PTR(retval);
 487
 488}
 489
 490struct inode *
 491v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 492		    struct super_block *sb, int new)
 493{
 494	struct p9_wstat *st;
 495	struct inode *inode = NULL;
 496
 497	st = p9_client_stat(fid);
 498	if (IS_ERR(st))
 499		return ERR_CAST(st);
 500
 501	inode = v9fs_qid_iget(sb, &st->qid, st, new);
 502	p9stat_free(st);
 503	kfree(st);
 504	return inode;
 505}
 506
 507/**
 508 * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
 509 * plan 9 AT flag.
 510 * @flags: flags to convert
 511 */
 512static int v9fs_at_to_dotl_flags(int flags)
 513{
 514	int rflags = 0;
 515
 516	if (flags & AT_REMOVEDIR)
 517		rflags |= P9_DOTL_AT_REMOVEDIR;
 518
 519	return rflags;
 520}
 521
 522/**
 523 * v9fs_dec_count - helper functon to drop i_nlink.
 524 *
 525 * If a directory had nlink <= 2 (including . and ..), then we should not drop
 526 * the link count, which indicates the underlying exported fs doesn't maintain
 527 * nlink accurately. e.g.
 528 * - overlayfs sets nlink to 1 for merged dir
 529 * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
 530 *   than EXT4_LINK_MAX (65000) links.
 531 *
 532 * @inode: inode whose nlink is being dropped
 533 */
 534static void v9fs_dec_count(struct inode *inode)
 535{
 536	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
 537		drop_nlink(inode);
 538}
 539
 540/**
 541 * v9fs_remove - helper function to remove files and directories
 542 * @dir: directory inode that is being deleted
 543 * @dentry:  dentry that is being deleted
 544 * @flags: removing a directory
 545 *
 546 */
 547
 548static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
 549{
 550	struct inode *inode;
 551	int retval = -EOPNOTSUPP;
 552	struct p9_fid *v9fid, *dfid;
 553	struct v9fs_session_info *v9ses;
 554
 555	p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
 556		 dir, dentry, flags);
 557
 558	v9ses = v9fs_inode2v9ses(dir);
 559	inode = d_inode(dentry);
 560	dfid = v9fs_parent_fid(dentry);
 561	if (IS_ERR(dfid)) {
 562		retval = PTR_ERR(dfid);
 563		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
 564		return retval;
 565	}
 566	if (v9fs_proto_dotl(v9ses))
 567		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
 568					    v9fs_at_to_dotl_flags(flags));
 569	p9_fid_put(dfid);
 570	if (retval == -EOPNOTSUPP) {
 571		/* Try the one based on path */
 572		v9fid = v9fs_fid_clone(dentry);
 573		if (IS_ERR(v9fid))
 574			return PTR_ERR(v9fid);
 575		retval = p9_client_remove(v9fid);
 576	}
 577	if (!retval) {
 578		/*
 579		 * directories on unlink should have zero
 580		 * link count
 581		 */
 582		if (flags & AT_REMOVEDIR) {
 583			clear_nlink(inode);
 584			v9fs_dec_count(dir);
 585		} else
 586			v9fs_dec_count(inode);
 587
 588		v9fs_invalidate_inode_attr(inode);
 589		v9fs_invalidate_inode_attr(dir);
 590
 591		/* invalidate all fids associated with dentry */
 592		/* NOTE: This will not include open fids */
 593		dentry->d_op->d_release(dentry);
 594	}
 595	return retval;
 596}
 597
 598/**
 599 * v9fs_create - Create a file
 600 * @v9ses: session information
 601 * @dir: directory that dentry is being created in
 602 * @dentry:  dentry that is being created
 603 * @extension: 9p2000.u extension string to support devices, etc.
 604 * @perm: create permissions
 605 * @mode: open mode
 606 *
 607 */
 608static struct p9_fid *
 609v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 610		struct dentry *dentry, char *extension, u32 perm, u8 mode)
 611{
 612	int err;
 613	const unsigned char *name;
 614	struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
 615	struct inode *inode;
 616
 617	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 618
 619	err = 0;
 620	name = dentry->d_name.name;
 621	dfid = v9fs_parent_fid(dentry);
 622	if (IS_ERR(dfid)) {
 623		err = PTR_ERR(dfid);
 624		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 625		return ERR_PTR(err);
 626	}
 627
 628	/* clone a fid to use for creation */
 629	ofid = clone_fid(dfid);
 630	if (IS_ERR(ofid)) {
 631		err = PTR_ERR(ofid);
 632		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 633		goto error;
 634	}
 635
 636	err = p9_client_fcreate(ofid, name, perm, mode, extension);
 637	if (err < 0) {
 638		p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 639		goto error;
 640	}
 641
 642	if (!(perm & P9_DMLINK)) {
 643		/* now walk from the parent so we can get unopened fid */
 644		fid = p9_client_walk(dfid, 1, &name, 1);
 645		if (IS_ERR(fid)) {
 646			err = PTR_ERR(fid);
 647			p9_debug(P9_DEBUG_VFS,
 648				   "p9_client_walk failed %d\n", err);
 649			goto error;
 650		}
 651		/*
 652		 * instantiate inode and assign the unopened fid to the dentry
 653		 */
 654		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 655		if (IS_ERR(inode)) {
 656			err = PTR_ERR(inode);
 657			p9_debug(P9_DEBUG_VFS,
 658				   "inode creation failed %d\n", err);
 659			goto error;
 660		}
 661		v9fs_fid_add(dentry, &fid);
 662		d_instantiate(dentry, inode);
 663	}
 664	p9_fid_put(dfid);
 665	return ofid;
 666error:
 667	p9_fid_put(dfid);
 668	p9_fid_put(ofid);
 669	p9_fid_put(fid);
 670	return ERR_PTR(err);
 671}
 672
 673/**
 674 * v9fs_vfs_create - VFS hook to create a regular file
 675 * @mnt_userns: The user namespace of the mount
 676 * @dir: The parent directory
 677 * @dentry: The name of file to be created
 678 * @mode: The UNIX file mode to set
 679 * @excl: True if the file must not yet exist
 680 *
 681 * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
 682 * for mknod(2).
 683 *
 684 */
 685
 686static int
 687v9fs_vfs_create(struct user_namespace *mnt_userns, struct inode *dir,
 688		struct dentry *dentry, umode_t mode, bool excl)
 689{
 690	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
 691	u32 perm = unixmode2p9mode(v9ses, mode);
 692	struct p9_fid *fid;
 693
 694	/* P9_OEXCL? */
 695	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
 696	if (IS_ERR(fid))
 697		return PTR_ERR(fid);
 698
 699	v9fs_invalidate_inode_attr(dir);
 700	p9_fid_put(fid);
 701
 702	return 0;
 703}
 704
 705/**
 706 * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 707 * @mnt_userns: The user namespace of the mount
 708 * @dir:  inode that is being unlinked
 709 * @dentry: dentry that is being unlinked
 710 * @mode: mode for new directory
 711 *
 712 */
 713
 714static int v9fs_vfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 715			  struct dentry *dentry, umode_t mode)
 716{
 717	int err;
 718	u32 perm;
 719	struct p9_fid *fid;
 720	struct v9fs_session_info *v9ses;
 721
 722	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 723	err = 0;
 724	v9ses = v9fs_inode2v9ses(dir);
 725	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 726	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 727	if (IS_ERR(fid)) {
 728		err = PTR_ERR(fid);
 729		fid = NULL;
 730	} else {
 731		inc_nlink(dir);
 732		v9fs_invalidate_inode_attr(dir);
 733	}
 734
 735	if (fid)
 736		p9_fid_put(fid);
 737
 738	return err;
 739}
 740
 741/**
 742 * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 743 * @dir:  inode that is being walked from
 744 * @dentry: dentry that is being walked to?
 745 * @flags: lookup flags (unused)
 746 *
 747 */
 748
 749struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 750				      unsigned int flags)
 751{
 752	struct dentry *res;
 753	struct v9fs_session_info *v9ses;
 754	struct p9_fid *dfid, *fid;
 755	struct inode *inode;
 756	const unsigned char *name;
 757
 758	p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
 759		 dir, dentry, dentry, flags);
 760
 761	if (dentry->d_name.len > NAME_MAX)
 762		return ERR_PTR(-ENAMETOOLONG);
 763
 764	v9ses = v9fs_inode2v9ses(dir);
 765	/* We can walk d_parent because we hold the dir->i_mutex */
 766	dfid = v9fs_parent_fid(dentry);
 767	if (IS_ERR(dfid))
 768		return ERR_CAST(dfid);
 769
 770	/*
 771	 * Make sure we don't use a wrong inode due to parallel
 772	 * unlink. For cached mode create calls request for new
 773	 * inode. But with cache disabled, lookup should do this.
 774	 */
 775	name = dentry->d_name.name;
 776	fid = p9_client_walk(dfid, 1, &name, 1);
 777	p9_fid_put(dfid);
 778	if (fid == ERR_PTR(-ENOENT))
 779		inode = NULL;
 780	else if (IS_ERR(fid))
 781		inode = ERR_CAST(fid);
 782	else if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 783		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 784	else
 785		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 786	/*
 787	 * If we had a rename on the server and a parallel lookup
 788	 * for the new name, then make sure we instantiate with
 789	 * the new name. ie look up for a/b, while on server somebody
 790	 * moved b under k and client parallely did a lookup for
 791	 * k/b.
 792	 */
 793	res = d_splice_alias(inode, dentry);
 794	if (!IS_ERR(fid)) {
 795		if (!res)
 796			v9fs_fid_add(dentry, &fid);
 797		else if (!IS_ERR(res))
 798			v9fs_fid_add(res, &fid);
 799		else
 800			p9_fid_put(fid);
 801	}
 802	return res;
 803}
 804
 805static int
 806v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 807		     struct file *file, unsigned int flags, umode_t mode)
 808{
 809	int err;
 810	u32 perm;
 811	struct v9fs_inode *v9inode;
 812	struct v9fs_session_info *v9ses;
 813	struct p9_fid *fid, *inode_fid;
 814	struct dentry *res = NULL;
 815	struct inode *inode;
 
 816
 817	if (d_in_lookup(dentry)) {
 818		res = v9fs_vfs_lookup(dir, dentry, 0);
 819		if (IS_ERR(res))
 820			return PTR_ERR(res);
 821
 822		if (res)
 823			dentry = res;
 824	}
 825
 826	/* Only creates */
 827	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
 828		return finish_no_open(file, res);
 829
 830	err = 0;
 831
 832	v9ses = v9fs_inode2v9ses(dir);
 833	perm = unixmode2p9mode(v9ses, mode);
 834	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 835				v9fs_uflags2omode(flags,
 836						v9fs_proto_dotu(v9ses)));
 
 
 
 
 
 837	if (IS_ERR(fid)) {
 838		err = PTR_ERR(fid);
 839		goto error;
 840	}
 841
 842	v9fs_invalidate_inode_attr(dir);
 843	inode = d_inode(dentry);
 844	v9inode = V9FS_I(inode);
 845	mutex_lock(&v9inode->v_mutex);
 846	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
 847	    !v9inode->writeback_fid &&
 848	    ((flags & O_ACCMODE) != O_RDONLY)) {
 849		/*
 850		 * clone a fid and add it to writeback_fid
 851		 * we do it during open time instead of
 852		 * page dirty time via write_begin/page_mkwrite
 853		 * because we want write after unlink usecase
 854		 * to work.
 855		 */
 856		inode_fid = v9fs_writeback_fid(dentry);
 857		if (IS_ERR(inode_fid)) {
 858			err = PTR_ERR(inode_fid);
 859			mutex_unlock(&v9inode->v_mutex);
 860			goto error;
 861		}
 862		v9inode->writeback_fid = (void *) inode_fid;
 863	}
 864	mutex_unlock(&v9inode->v_mutex);
 865	err = finish_open(file, dentry, generic_file_open);
 866	if (err)
 867		goto error;
 868
 869	file->private_data = fid;
 870	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 
 871		fscache_use_cookie(v9fs_inode_cookie(v9inode),
 872				   file->f_mode & FMODE_WRITE);
 
 
 
 873	v9fs_open_fid_add(inode, &fid);
 874
 875	file->f_mode |= FMODE_CREATED;
 876out:
 877	dput(res);
 878	return err;
 879
 880error:
 881	p9_fid_put(fid);
 882	goto out;
 883}
 884
 885/**
 886 * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 887 * @i:  inode that is being unlinked
 888 * @d: dentry that is being unlinked
 889 *
 890 */
 891
 892int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 893{
 894	return v9fs_remove(i, d, 0);
 895}
 896
 897/**
 898 * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 899 * @i:  inode that is being unlinked
 900 * @d: dentry that is being unlinked
 901 *
 902 */
 903
 904int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 905{
 906	return v9fs_remove(i, d, AT_REMOVEDIR);
 907}
 908
 909/**
 910 * v9fs_vfs_rename - VFS hook to rename an inode
 911 * @mnt_userns: The user namespace of the mount
 912 * @old_dir:  old dir inode
 913 * @old_dentry: old dentry
 914 * @new_dir: new dir inode
 915 * @new_dentry: new dentry
 916 * @flags: RENAME_* flags
 917 *
 918 */
 919
 920int
 921v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 922		struct dentry *old_dentry, struct inode *new_dir,
 923		struct dentry *new_dentry, unsigned int flags)
 924{
 925	int retval;
 926	struct inode *old_inode;
 927	struct inode *new_inode;
 928	struct v9fs_session_info *v9ses;
 929	struct p9_fid *oldfid = NULL, *dfid = NULL;
 930	struct p9_fid *olddirfid = NULL;
 931	struct p9_fid *newdirfid = NULL;
 932	struct p9_wstat wstat;
 933
 934	if (flags)
 935		return -EINVAL;
 936
 937	p9_debug(P9_DEBUG_VFS, "\n");
 938	retval = 0;
 939	old_inode = d_inode(old_dentry);
 940	new_inode = d_inode(new_dentry);
 941	v9ses = v9fs_inode2v9ses(old_inode);
 942	oldfid = v9fs_fid_lookup(old_dentry);
 943	if (IS_ERR(oldfid))
 944		return PTR_ERR(oldfid);
 945
 946	dfid = v9fs_parent_fid(old_dentry);
 947	olddirfid = clone_fid(dfid);
 948	p9_fid_put(dfid);
 949	dfid = NULL;
 950
 951	if (IS_ERR(olddirfid)) {
 952		retval = PTR_ERR(olddirfid);
 953		goto error;
 954	}
 955
 956	dfid = v9fs_parent_fid(new_dentry);
 957	newdirfid = clone_fid(dfid);
 958	p9_fid_put(dfid);
 959	dfid = NULL;
 960
 961	if (IS_ERR(newdirfid)) {
 962		retval = PTR_ERR(newdirfid);
 963		goto error;
 964	}
 965
 966	down_write(&v9ses->rename_sem);
 967	if (v9fs_proto_dotl(v9ses)) {
 968		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
 969					    newdirfid, new_dentry->d_name.name);
 970		if (retval == -EOPNOTSUPP)
 971			retval = p9_client_rename(oldfid, newdirfid,
 972						  new_dentry->d_name.name);
 973		if (retval != -EOPNOTSUPP)
 974			goto error_locked;
 975	}
 976	if (old_dentry->d_parent != new_dentry->d_parent) {
 977		/*
 978		 * 9P .u can only handle file rename in the same directory
 979		 */
 980
 981		p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
 982		retval = -EXDEV;
 983		goto error_locked;
 984	}
 985	v9fs_blank_wstat(&wstat);
 986	wstat.muid = v9ses->uname;
 987	wstat.name = new_dentry->d_name.name;
 988	retval = p9_client_wstat(oldfid, &wstat);
 989
 990error_locked:
 991	if (!retval) {
 992		if (new_inode) {
 993			if (S_ISDIR(new_inode->i_mode))
 994				clear_nlink(new_inode);
 995			else
 996				v9fs_dec_count(new_inode);
 997		}
 998		if (S_ISDIR(old_inode->i_mode)) {
 999			if (!new_inode)
1000				inc_nlink(new_dir);
1001			v9fs_dec_count(old_dir);
1002		}
1003		v9fs_invalidate_inode_attr(old_inode);
1004		v9fs_invalidate_inode_attr(old_dir);
1005		v9fs_invalidate_inode_attr(new_dir);
1006
1007		/* successful rename */
1008		d_move(old_dentry, new_dentry);
1009	}
1010	up_write(&v9ses->rename_sem);
1011
1012error:
1013	p9_fid_put(newdirfid);
1014	p9_fid_put(olddirfid);
1015	p9_fid_put(oldfid);
1016	return retval;
1017}
1018
1019/**
1020 * v9fs_vfs_getattr - retrieve file metadata
1021 * @mnt_userns: The user namespace of the mount
1022 * @path: Object to query
1023 * @stat: metadata structure to populate
1024 * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
1025 * @flags: AT_STATX_xxx setting
1026 *
1027 */
1028
1029static int
1030v9fs_vfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
1031		 struct kstat *stat, u32 request_mask, unsigned int flags)
1032{
1033	struct dentry *dentry = path->dentry;
 
1034	struct v9fs_session_info *v9ses;
1035	struct p9_fid *fid;
1036	struct p9_wstat *st;
1037
1038	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1039	v9ses = v9fs_dentry2v9ses(dentry);
1040	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
1041		generic_fillattr(&init_user_ns, d_inode(dentry), stat);
1042		return 0;
 
 
 
 
 
 
 
 
1043	}
1044	fid = v9fs_fid_lookup(dentry);
1045	if (IS_ERR(fid))
1046		return PTR_ERR(fid);
1047
1048	st = p9_client_stat(fid);
1049	p9_fid_put(fid);
1050	if (IS_ERR(st))
1051		return PTR_ERR(st);
1052
1053	v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
1054	generic_fillattr(&init_user_ns, d_inode(dentry), stat);
1055
1056	p9stat_free(st);
1057	kfree(st);
1058	return 0;
1059}
1060
1061/**
1062 * v9fs_vfs_setattr - set file metadata
1063 * @mnt_userns: The user namespace of the mount
1064 * @dentry: file whose metadata to set
1065 * @iattr: metadata assignment structure
1066 *
1067 */
1068
1069static int v9fs_vfs_setattr(struct user_namespace *mnt_userns,
1070			    struct dentry *dentry, struct iattr *iattr)
1071{
1072	int retval, use_dentry = 0;
1073	struct inode *inode = d_inode(dentry);
1074	struct v9fs_inode *v9inode = V9FS_I(inode);
1075	struct v9fs_session_info *v9ses;
1076	struct p9_fid *fid = NULL;
1077	struct p9_wstat wstat;
1078
1079	p9_debug(P9_DEBUG_VFS, "\n");
1080	retval = setattr_prepare(&init_user_ns, dentry, iattr);
1081	if (retval)
1082		return retval;
1083
1084	retval = -EPERM;
1085	v9ses = v9fs_dentry2v9ses(dentry);
1086	if (iattr->ia_valid & ATTR_FILE) {
1087		fid = iattr->ia_file->private_data;
1088		WARN_ON(!fid);
1089	}
1090	if (!fid) {
1091		fid = v9fs_fid_lookup(dentry);
1092		use_dentry = 1;
1093	}
1094	if (IS_ERR(fid))
1095		return PTR_ERR(fid);
1096
1097	v9fs_blank_wstat(&wstat);
1098	if (iattr->ia_valid & ATTR_MODE)
1099		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1100
1101	if (iattr->ia_valid & ATTR_MTIME)
1102		wstat.mtime = iattr->ia_mtime.tv_sec;
1103
1104	if (iattr->ia_valid & ATTR_ATIME)
1105		wstat.atime = iattr->ia_atime.tv_sec;
1106
1107	if (iattr->ia_valid & ATTR_SIZE)
1108		wstat.length = iattr->ia_size;
1109
1110	if (v9fs_proto_dotu(v9ses)) {
1111		if (iattr->ia_valid & ATTR_UID)
1112			wstat.n_uid = iattr->ia_uid;
1113
1114		if (iattr->ia_valid & ATTR_GID)
1115			wstat.n_gid = iattr->ia_gid;
1116	}
1117
1118	/* Write all dirty data */
1119	if (d_is_reg(dentry))
1120		filemap_write_and_wait(inode->i_mapping);
 
 
 
 
1121
1122	retval = p9_client_wstat(fid, &wstat);
1123
1124	if (use_dentry)
1125		p9_fid_put(fid);
1126
1127	if (retval < 0)
1128		return retval;
1129
1130	if ((iattr->ia_valid & ATTR_SIZE) &&
1131	    iattr->ia_size != i_size_read(inode)) {
1132		truncate_setsize(inode, iattr->ia_size);
1133		fscache_resize_cookie(v9fs_inode_cookie(v9inode), iattr->ia_size);
 
 
 
 
 
 
 
 
1134	}
1135
1136	v9fs_invalidate_inode_attr(inode);
1137
1138	setattr_copy(&init_user_ns, inode, iattr);
1139	mark_inode_dirty(inode);
1140	return 0;
1141}
1142
1143/**
1144 * v9fs_stat2inode - populate an inode structure with mistat info
1145 * @stat: Plan 9 metadata (mistat) structure
1146 * @inode: inode to populate
1147 * @sb: superblock of filesystem
1148 * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1149 *
1150 */
1151
1152void
1153v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1154		 struct super_block *sb, unsigned int flags)
1155{
1156	umode_t mode;
1157	struct v9fs_session_info *v9ses = sb->s_fs_info;
1158	struct v9fs_inode *v9inode = V9FS_I(inode);
1159
1160	set_nlink(inode, 1);
1161
1162	inode->i_atime.tv_sec = stat->atime;
1163	inode->i_mtime.tv_sec = stat->mtime;
1164	inode->i_ctime.tv_sec = stat->mtime;
1165
1166	inode->i_uid = v9ses->dfltuid;
1167	inode->i_gid = v9ses->dfltgid;
1168
1169	if (v9fs_proto_dotu(v9ses)) {
1170		inode->i_uid = stat->n_uid;
1171		inode->i_gid = stat->n_gid;
1172	}
1173	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1174		if (v9fs_proto_dotu(v9ses)) {
1175			unsigned int i_nlink;
1176			/*
1177			 * Hadlink support got added later to the .u extension.
1178			 * So there can be a server out there that doesn't
1179			 * support this even with .u extension. That would
1180			 * just leave us with stat->extension being an empty
1181			 * string, though.
1182			 */
1183			/* HARDLINKCOUNT %u */
1184			if (sscanf(stat->extension,
1185				   " HARDLINKCOUNT %u", &i_nlink) == 1)
1186				set_nlink(inode, i_nlink);
1187		}
1188	}
1189	mode = p9mode2perm(v9ses, stat);
1190	mode |= inode->i_mode & ~S_IALLUGO;
1191	inode->i_mode = mode;
1192
 
1193	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1194		v9fs_i_size_write(inode, stat->length);
1195	/* not real number of blocks, but 512 byte ones ... */
1196	inode->i_blocks = (stat->length + 512 - 1) >> 9;
1197	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1198}
1199
1200/**
1201 * v9fs_qid2ino - convert qid into inode number
1202 * @qid: qid to hash
1203 *
1204 * BUG: potential for inode number collisions?
1205 */
1206
1207ino_t v9fs_qid2ino(struct p9_qid *qid)
1208{
1209	u64 path = qid->path + 2;
1210	ino_t i = 0;
1211
1212	if (sizeof(ino_t) == sizeof(path))
1213		memcpy(&i, &path, sizeof(ino_t));
1214	else
1215		i = (ino_t) (path ^ (path >> 32));
1216
1217	return i;
1218}
1219
1220/**
1221 * v9fs_vfs_get_link - follow a symlink path
1222 * @dentry: dentry for symlink
1223 * @inode: inode for symlink
1224 * @done: delayed call for when we are done with the return value
1225 */
1226
1227static const char *v9fs_vfs_get_link(struct dentry *dentry,
1228				     struct inode *inode,
1229				     struct delayed_call *done)
1230{
1231	struct v9fs_session_info *v9ses;
1232	struct p9_fid *fid;
1233	struct p9_wstat *st;
1234	char *res;
1235
1236	if (!dentry)
1237		return ERR_PTR(-ECHILD);
1238
1239	v9ses = v9fs_dentry2v9ses(dentry);
1240	if (!v9fs_proto_dotu(v9ses))
1241		return ERR_PTR(-EBADF);
1242
1243	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1244	fid = v9fs_fid_lookup(dentry);
1245
1246	if (IS_ERR(fid))
1247		return ERR_CAST(fid);
1248
1249	st = p9_client_stat(fid);
1250	p9_fid_put(fid);
1251	if (IS_ERR(st))
1252		return ERR_CAST(st);
1253
1254	if (!(st->mode & P9_DMSYMLINK)) {
1255		p9stat_free(st);
1256		kfree(st);
1257		return ERR_PTR(-EINVAL);
1258	}
1259	res = st->extension;
1260	st->extension = NULL;
1261	if (strlen(res) >= PATH_MAX)
1262		res[PATH_MAX - 1] = '\0';
1263
1264	p9stat_free(st);
1265	kfree(st);
1266	set_delayed_call(done, kfree_link, res);
1267	return res;
1268}
1269
1270/**
1271 * v9fs_vfs_mkspecial - create a special file
1272 * @dir: inode to create special file in
1273 * @dentry: dentry to create
1274 * @perm: mode to create special file
1275 * @extension: 9p2000.u format extension string representing special file
1276 *
1277 */
1278
1279static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1280	u32 perm, const char *extension)
1281{
1282	struct p9_fid *fid;
1283	struct v9fs_session_info *v9ses;
1284
1285	v9ses = v9fs_inode2v9ses(dir);
1286	if (!v9fs_proto_dotu(v9ses)) {
1287		p9_debug(P9_DEBUG_ERROR, "not extended\n");
1288		return -EPERM;
1289	}
1290
1291	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1292								P9_OREAD);
1293	if (IS_ERR(fid))
1294		return PTR_ERR(fid);
1295
1296	v9fs_invalidate_inode_attr(dir);
1297	p9_fid_put(fid);
1298	return 0;
1299}
1300
1301/**
1302 * v9fs_vfs_symlink - helper function to create symlinks
1303 * @mnt_userns: The user namespace of the mount
1304 * @dir: directory inode containing symlink
1305 * @dentry: dentry for symlink
1306 * @symname: symlink data
1307 *
1308 * See Also: 9P2000.u RFC for more information
1309 *
1310 */
1311
1312static int
1313v9fs_vfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
1314		 struct dentry *dentry, const char *symname)
1315{
1316	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1317		 dir->i_ino, dentry, symname);
1318
1319	return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1320}
1321
1322#define U32_MAX_DIGITS 10
1323
1324/**
1325 * v9fs_vfs_link - create a hardlink
1326 * @old_dentry: dentry for file to link to
1327 * @dir: inode destination for new link
1328 * @dentry: dentry for link
1329 *
1330 */
1331
1332static int
1333v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1334	      struct dentry *dentry)
1335{
1336	int retval;
1337	char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1338	struct p9_fid *oldfid;
1339
1340	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1341		 dir->i_ino, dentry, old_dentry);
1342
1343	oldfid = v9fs_fid_clone(old_dentry);
1344	if (IS_ERR(oldfid))
1345		return PTR_ERR(oldfid);
1346
1347	sprintf(name, "%d\n", oldfid->fid);
1348	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1349	if (!retval) {
1350		v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1351		v9fs_invalidate_inode_attr(dir);
1352	}
1353	p9_fid_put(oldfid);
1354	return retval;
1355}
1356
1357/**
1358 * v9fs_vfs_mknod - create a special file
1359 * @mnt_userns: The user namespace of the mount
1360 * @dir: inode destination for new link
1361 * @dentry: dentry for file
1362 * @mode: mode for creation
1363 * @rdev: device associated with special file
1364 *
1365 */
1366
1367static int
1368v9fs_vfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
1369	       struct dentry *dentry, umode_t mode, dev_t rdev)
1370{
1371	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1372	int retval;
1373	char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1374	u32 perm;
1375
1376	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %x MAJOR: %u MINOR: %u\n",
1377		 dir->i_ino, dentry, mode,
1378		 MAJOR(rdev), MINOR(rdev));
1379
1380	/* build extension */
1381	if (S_ISBLK(mode))
1382		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1383	else if (S_ISCHR(mode))
1384		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1385	else
1386		*name = 0;
1387
1388	perm = unixmode2p9mode(v9ses, mode);
1389	retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1390
1391	return retval;
1392}
1393
1394int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1395{
1396	int umode;
1397	dev_t rdev;
1398	struct p9_wstat *st;
1399	struct v9fs_session_info *v9ses;
1400	unsigned int flags;
1401
1402	v9ses = v9fs_inode2v9ses(inode);
1403	st = p9_client_stat(fid);
1404	if (IS_ERR(st))
1405		return PTR_ERR(st);
1406	/*
1407	 * Don't update inode if the file type is different
1408	 */
1409	umode = p9mode2unixmode(v9ses, st, &rdev);
1410	if (inode_wrong_type(inode, umode))
1411		goto out;
1412
1413	/*
1414	 * We don't want to refresh inode->i_size,
1415	 * because we may have cached data
1416	 */
1417	flags = (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) ?
1418		V9FS_STAT2INODE_KEEP_ISIZE : 0;
1419	v9fs_stat2inode(st, inode, inode->i_sb, flags);
1420out:
1421	p9stat_free(st);
1422	kfree(st);
1423	return 0;
1424}
1425
1426static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1427	.create = v9fs_vfs_create,
1428	.lookup = v9fs_vfs_lookup,
1429	.atomic_open = v9fs_vfs_atomic_open,
1430	.symlink = v9fs_vfs_symlink,
1431	.link = v9fs_vfs_link,
1432	.unlink = v9fs_vfs_unlink,
1433	.mkdir = v9fs_vfs_mkdir,
1434	.rmdir = v9fs_vfs_rmdir,
1435	.mknod = v9fs_vfs_mknod,
1436	.rename = v9fs_vfs_rename,
1437	.getattr = v9fs_vfs_getattr,
1438	.setattr = v9fs_vfs_setattr,
1439};
1440
1441static const struct inode_operations v9fs_dir_inode_operations = {
1442	.create = v9fs_vfs_create,
1443	.lookup = v9fs_vfs_lookup,
1444	.atomic_open = v9fs_vfs_atomic_open,
1445	.unlink = v9fs_vfs_unlink,
1446	.mkdir = v9fs_vfs_mkdir,
1447	.rmdir = v9fs_vfs_rmdir,
1448	.mknod = v9fs_vfs_mknod,
1449	.rename = v9fs_vfs_rename,
1450	.getattr = v9fs_vfs_getattr,
1451	.setattr = v9fs_vfs_setattr,
1452};
1453
1454static const struct inode_operations v9fs_file_inode_operations = {
1455	.getattr = v9fs_vfs_getattr,
1456	.setattr = v9fs_vfs_setattr,
1457};
1458
1459static const struct inode_operations v9fs_symlink_inode_operations = {
1460	.get_link = v9fs_vfs_get_link,
1461	.getattr = v9fs_vfs_getattr,
1462	.setattr = v9fs_vfs_setattr,
1463};
1464
v6.13.7
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * This file contains vfs inode ops for the 9P2000 protocol.
   4 *
   5 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   6 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   7 */
   8
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/module.h>
  12#include <linux/errno.h>
  13#include <linux/fs.h>
  14#include <linux/file.h>
  15#include <linux/pagemap.h>
  16#include <linux/stat.h>
  17#include <linux/string.h>
 
  18#include <linux/namei.h>
  19#include <linux/sched.h>
  20#include <linux/slab.h>
  21#include <linux/xattr.h>
  22#include <linux/posix_acl.h>
  23#include <net/9p/9p.h>
  24#include <net/9p/client.h>
  25
  26#include "v9fs.h"
  27#include "v9fs_vfs.h"
  28#include "fid.h"
  29#include "cache.h"
  30#include "xattr.h"
  31#include "acl.h"
  32
  33static const struct inode_operations v9fs_dir_inode_operations;
  34static const struct inode_operations v9fs_dir_inode_operations_dotu;
  35static const struct inode_operations v9fs_file_inode_operations;
  36static const struct inode_operations v9fs_symlink_inode_operations;
  37
  38/**
  39 * unixmode2p9mode - convert unix mode bits to plan 9
  40 * @v9ses: v9fs session information
  41 * @mode: mode to convert
  42 *
  43 */
  44
  45static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
  46{
  47	int res;
  48
  49	res = mode & 0777;
  50	if (S_ISDIR(mode))
  51		res |= P9_DMDIR;
  52	if (v9fs_proto_dotu(v9ses)) {
  53		if (v9ses->nodev == 0) {
  54			if (S_ISSOCK(mode))
  55				res |= P9_DMSOCKET;
  56			if (S_ISFIFO(mode))
  57				res |= P9_DMNAMEDPIPE;
  58			if (S_ISBLK(mode))
  59				res |= P9_DMDEVICE;
  60			if (S_ISCHR(mode))
  61				res |= P9_DMDEVICE;
  62		}
  63
  64		if ((mode & S_ISUID) == S_ISUID)
  65			res |= P9_DMSETUID;
  66		if ((mode & S_ISGID) == S_ISGID)
  67			res |= P9_DMSETGID;
  68		if ((mode & S_ISVTX) == S_ISVTX)
  69			res |= P9_DMSETVTX;
  70	}
  71	return res;
  72}
  73
  74/**
  75 * p9mode2perm- convert plan9 mode bits to unix permission bits
  76 * @v9ses: v9fs session information
  77 * @stat: p9_wstat from which mode need to be derived
  78 *
  79 */
  80static int p9mode2perm(struct v9fs_session_info *v9ses,
  81		       struct p9_wstat *stat)
  82{
  83	int res;
  84	int mode = stat->mode;
  85
  86	res = mode & 0777; /* S_IRWXUGO */
  87	if (v9fs_proto_dotu(v9ses)) {
  88		if ((mode & P9_DMSETUID) == P9_DMSETUID)
  89			res |= S_ISUID;
  90
  91		if ((mode & P9_DMSETGID) == P9_DMSETGID)
  92			res |= S_ISGID;
  93
  94		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
  95			res |= S_ISVTX;
  96	}
  97	return res;
  98}
  99
 100/**
 101 * p9mode2unixmode- convert plan9 mode bits to unix mode bits
 102 * @v9ses: v9fs session information
 103 * @stat: p9_wstat from which mode need to be derived
 104 * @rdev: major number, minor number in case of device files.
 105 *
 106 */
 107static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
 108			       struct p9_wstat *stat, dev_t *rdev)
 109{
 110	int res, r;
 111	u32 mode = stat->mode;
 112
 113	*rdev = 0;
 114	res = p9mode2perm(v9ses, stat);
 115
 116	if ((mode & P9_DMDIR) == P9_DMDIR)
 117		res |= S_IFDIR;
 118	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
 119		res |= S_IFLNK;
 120	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
 121		 && (v9ses->nodev == 0))
 122		res |= S_IFSOCK;
 123	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
 124		 && (v9ses->nodev == 0))
 125		res |= S_IFIFO;
 126	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 127		 && (v9ses->nodev == 0)) {
 128		char type = 0;
 129		int major = -1, minor = -1;
 130
 131		r = sscanf(stat->extension, "%c %i %i", &type, &major, &minor);
 132		if (r != 3) {
 133			p9_debug(P9_DEBUG_ERROR,
 134				 "invalid device string, umode will be bogus: %s\n",
 135				 stat->extension);
 136			return res;
 137		}
 138		switch (type) {
 139		case 'c':
 140			res |= S_IFCHR;
 141			break;
 142		case 'b':
 143			res |= S_IFBLK;
 144			break;
 145		default:
 146			p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
 147				 type, stat->extension);
 148		}
 149		*rdev = MKDEV(major, minor);
 150	} else
 151		res |= S_IFREG;
 152
 153	return res;
 154}
 155
 156/**
 157 * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 158 * @uflags: flags to convert
 159 * @extended: if .u extensions are active
 160 */
 161
 162int v9fs_uflags2omode(int uflags, int extended)
 163{
 164	int ret;
 165
 
 166	switch (uflags&3) {
 167	default:
 168	case O_RDONLY:
 169		ret = P9_OREAD;
 170		break;
 171
 172	case O_WRONLY:
 173		ret = P9_OWRITE;
 174		break;
 175
 176	case O_RDWR:
 177		ret = P9_ORDWR;
 178		break;
 179	}
 180
 181	if (uflags & O_TRUNC)
 182		ret |= P9_OTRUNC;
 183
 184	if (extended) {
 185		if (uflags & O_EXCL)
 186			ret |= P9_OEXCL;
 187
 188		if (uflags & O_APPEND)
 189			ret |= P9_OAPPEND;
 190	}
 191
 192	return ret;
 193}
 194
 195/**
 196 * v9fs_blank_wstat - helper function to setup a 9P stat structure
 197 * @wstat: structure to initialize
 198 *
 199 */
 200
 201void
 202v9fs_blank_wstat(struct p9_wstat *wstat)
 203{
 204	wstat->type = ~0;
 205	wstat->dev = ~0;
 206	wstat->qid.type = ~0;
 207	wstat->qid.version = ~0;
 208	*((long long *)&wstat->qid.path) = ~0;
 209	wstat->mode = ~0;
 210	wstat->atime = ~0;
 211	wstat->mtime = ~0;
 212	wstat->length = ~0;
 213	wstat->name = NULL;
 214	wstat->uid = NULL;
 215	wstat->gid = NULL;
 216	wstat->muid = NULL;
 217	wstat->n_uid = INVALID_UID;
 218	wstat->n_gid = INVALID_GID;
 219	wstat->n_muid = INVALID_UID;
 220	wstat->extension = NULL;
 221}
 222
 223/**
 224 * v9fs_alloc_inode - helper function to allocate an inode
 225 * @sb: The superblock to allocate the inode from
 226 */
 227struct inode *v9fs_alloc_inode(struct super_block *sb)
 228{
 229	struct v9fs_inode *v9inode;
 230
 231	v9inode = alloc_inode_sb(sb, v9fs_inode_cache, GFP_KERNEL);
 232	if (!v9inode)
 233		return NULL;
 
 234	v9inode->cache_validity = 0;
 235	mutex_init(&v9inode->v_mutex);
 236	return &v9inode->netfs.inode;
 237}
 238
 239/**
 240 * v9fs_free_inode - destroy an inode
 241 * @inode: The inode to be freed
 242 */
 243
 244void v9fs_free_inode(struct inode *inode)
 245{
 246	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
 247}
 248
 249/*
 250 * Set parameters for the netfs library
 251 */
 252void v9fs_set_netfs_context(struct inode *inode)
 253{
 254	struct v9fs_inode *v9inode = V9FS_I(inode);
 255	netfs_inode_init(&v9inode->netfs, &v9fs_req_ops, true);
 256}
 257
 258int v9fs_init_inode(struct v9fs_session_info *v9ses,
 259		    struct inode *inode, umode_t mode, dev_t rdev)
 260{
 261	int err = 0;
 262
 263	inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
 264	inode->i_blocks = 0;
 265	inode->i_rdev = rdev;
 266	simple_inode_init_ts(inode);
 267	inode->i_mapping->a_ops = &v9fs_addr_operations;
 268	inode->i_private = NULL;
 269
 270	switch (mode & S_IFMT) {
 271	case S_IFIFO:
 272	case S_IFBLK:
 273	case S_IFCHR:
 274	case S_IFSOCK:
 275		if (v9fs_proto_dotl(v9ses)) {
 276			inode->i_op = &v9fs_file_inode_operations_dotl;
 277		} else if (v9fs_proto_dotu(v9ses)) {
 278			inode->i_op = &v9fs_file_inode_operations;
 279		} else {
 280			p9_debug(P9_DEBUG_ERROR,
 281				 "special files without extended mode\n");
 282			err = -EINVAL;
 283			goto error;
 284		}
 285		init_special_inode(inode, inode->i_mode, inode->i_rdev);
 286		break;
 287	case S_IFREG:
 288		if (v9fs_proto_dotl(v9ses)) {
 289			inode->i_op = &v9fs_file_inode_operations_dotl;
 290			inode->i_fop = &v9fs_file_operations_dotl;
 
 
 
 
 
 
 
 291		} else {
 292			inode->i_op = &v9fs_file_inode_operations;
 293			inode->i_fop = &v9fs_file_operations;
 
 
 
 
 
 
 
 294		}
 295
 296		break;
 297	case S_IFLNK:
 298		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 299			p9_debug(P9_DEBUG_ERROR,
 300				 "extended modes used with legacy protocol\n");
 301			err = -EINVAL;
 302			goto error;
 303		}
 304
 305		if (v9fs_proto_dotl(v9ses))
 306			inode->i_op = &v9fs_symlink_inode_operations_dotl;
 307		else
 308			inode->i_op = &v9fs_symlink_inode_operations;
 309
 310		break;
 311	case S_IFDIR:
 312		inc_nlink(inode);
 313		if (v9fs_proto_dotl(v9ses))
 314			inode->i_op = &v9fs_dir_inode_operations_dotl;
 315		else if (v9fs_proto_dotu(v9ses))
 316			inode->i_op = &v9fs_dir_inode_operations_dotu;
 317		else
 318			inode->i_op = &v9fs_dir_inode_operations;
 319
 320		if (v9fs_proto_dotl(v9ses))
 321			inode->i_fop = &v9fs_dir_operations_dotl;
 322		else
 323			inode->i_fop = &v9fs_dir_operations;
 324
 325		break;
 326	default:
 327		p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
 328			 mode, mode & S_IFMT);
 329		err = -EINVAL;
 330		goto error;
 331	}
 
 
 332error:
 333	return err;
 334
 335}
 336
 337/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 338 * v9fs_evict_inode - Remove an inode from the inode cache
 339 * @inode: inode to release
 340 *
 341 */
 342void v9fs_evict_inode(struct inode *inode)
 343{
 344	struct v9fs_inode __maybe_unused *v9inode = V9FS_I(inode);
 345	__le32 __maybe_unused version;
 346
 347	if (!is_bad_inode(inode)) {
 348		netfs_wait_for_outstanding_io(inode);
 349		truncate_inode_pages_final(&inode->i_data);
 350
 351		version = cpu_to_le32(v9inode->qid.version);
 352		netfs_clear_inode_writeback(inode, &version);
 353
 354		clear_inode(inode);
 355		filemap_fdatawrite(&inode->i_data);
 356
 357#ifdef CONFIG_9P_FSCACHE
 358		if (v9fs_inode_cookie(v9inode))
 359			fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
 360#endif
 361	} else
 362		clear_inode(inode);
 363}
 364
 365static int v9fs_test_inode(struct inode *inode, void *data)
 366{
 367	int umode;
 368	dev_t rdev;
 369	struct v9fs_inode *v9inode = V9FS_I(inode);
 370	struct p9_wstat *st = (struct p9_wstat *)data;
 371	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 372
 373	umode = p9mode2unixmode(v9ses, st, &rdev);
 374	/* don't match inode of different type */
 375	if (inode_wrong_type(inode, umode))
 376		return 0;
 377
 378	/* compare qid details */
 379	if (memcmp(&v9inode->qid.version,
 380		   &st->qid.version, sizeof(v9inode->qid.version)))
 381		return 0;
 382
 383	if (v9inode->qid.type != st->qid.type)
 384		return 0;
 385
 386	if (v9inode->qid.path != st->qid.path)
 387		return 0;
 388	return 1;
 389}
 390
 391static int v9fs_test_new_inode(struct inode *inode, void *data)
 392{
 393	return 0;
 394}
 395
 396static int v9fs_set_inode(struct inode *inode,  void *data)
 397{
 398	struct v9fs_inode *v9inode = V9FS_I(inode);
 399	struct p9_wstat *st = (struct p9_wstat *)data;
 400
 401	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
 402	return 0;
 403}
 404
 405static struct inode *v9fs_qid_iget(struct super_block *sb,
 406				   struct p9_qid *qid,
 407				   struct p9_wstat *st,
 408				   int new)
 409{
 410	dev_t rdev;
 411	int retval;
 412	umode_t umode;
 
 413	struct inode *inode;
 414	struct v9fs_session_info *v9ses = sb->s_fs_info;
 415	int (*test)(struct inode *inode, void *data);
 416
 417	if (new)
 418		test = v9fs_test_new_inode;
 419	else
 420		test = v9fs_test_inode;
 421
 422	inode = iget5_locked(sb, QID2INO(qid), test, v9fs_set_inode, st);
 
 423	if (!inode)
 424		return ERR_PTR(-ENOMEM);
 425	if (!(inode->i_state & I_NEW))
 426		return inode;
 427	/*
 428	 * initialize the inode with the stat info
 429	 * FIXME!! we may need support for stale inodes
 430	 * later.
 431	 */
 432	inode->i_ino = QID2INO(qid);
 433	umode = p9mode2unixmode(v9ses, st, &rdev);
 434	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 435	if (retval)
 436		goto error;
 437
 438	v9fs_stat2inode(st, inode, sb, 0);
 439	v9fs_set_netfs_context(inode);
 440	v9fs_cache_inode_get_cookie(inode);
 441	unlock_new_inode(inode);
 442	return inode;
 443error:
 444	iget_failed(inode);
 445	return ERR_PTR(retval);
 446
 447}
 448
 449struct inode *
 450v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 451		    struct super_block *sb, int new)
 452{
 453	struct p9_wstat *st;
 454	struct inode *inode = NULL;
 455
 456	st = p9_client_stat(fid);
 457	if (IS_ERR(st))
 458		return ERR_CAST(st);
 459
 460	inode = v9fs_qid_iget(sb, &st->qid, st, new);
 461	p9stat_free(st);
 462	kfree(st);
 463	return inode;
 464}
 465
 466/**
 467 * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
 468 * plan 9 AT flag.
 469 * @flags: flags to convert
 470 */
 471static int v9fs_at_to_dotl_flags(int flags)
 472{
 473	int rflags = 0;
 474
 475	if (flags & AT_REMOVEDIR)
 476		rflags |= P9_DOTL_AT_REMOVEDIR;
 477
 478	return rflags;
 479}
 480
 481/**
 482 * v9fs_dec_count - helper functon to drop i_nlink.
 483 *
 484 * If a directory had nlink <= 2 (including . and ..), then we should not drop
 485 * the link count, which indicates the underlying exported fs doesn't maintain
 486 * nlink accurately. e.g.
 487 * - overlayfs sets nlink to 1 for merged dir
 488 * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
 489 *   than EXT4_LINK_MAX (65000) links.
 490 *
 491 * @inode: inode whose nlink is being dropped
 492 */
 493static void v9fs_dec_count(struct inode *inode)
 494{
 495	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
 496		drop_nlink(inode);
 497}
 498
 499/**
 500 * v9fs_remove - helper function to remove files and directories
 501 * @dir: directory inode that is being deleted
 502 * @dentry:  dentry that is being deleted
 503 * @flags: removing a directory
 504 *
 505 */
 506
 507static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
 508{
 509	struct inode *inode;
 510	int retval = -EOPNOTSUPP;
 511	struct p9_fid *v9fid, *dfid;
 512	struct v9fs_session_info *v9ses;
 513
 514	p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
 515		 dir, dentry, flags);
 516
 517	v9ses = v9fs_inode2v9ses(dir);
 518	inode = d_inode(dentry);
 519	dfid = v9fs_parent_fid(dentry);
 520	if (IS_ERR(dfid)) {
 521		retval = PTR_ERR(dfid);
 522		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
 523		return retval;
 524	}
 525	if (v9fs_proto_dotl(v9ses))
 526		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
 527					    v9fs_at_to_dotl_flags(flags));
 528	p9_fid_put(dfid);
 529	if (retval == -EOPNOTSUPP) {
 530		/* Try the one based on path */
 531		v9fid = v9fs_fid_clone(dentry);
 532		if (IS_ERR(v9fid))
 533			return PTR_ERR(v9fid);
 534		retval = p9_client_remove(v9fid);
 535	}
 536	if (!retval) {
 537		/*
 538		 * directories on unlink should have zero
 539		 * link count
 540		 */
 541		if (flags & AT_REMOVEDIR) {
 542			clear_nlink(inode);
 543			v9fs_dec_count(dir);
 544		} else
 545			v9fs_dec_count(inode);
 546
 547		v9fs_invalidate_inode_attr(inode);
 548		v9fs_invalidate_inode_attr(dir);
 549
 550		/* invalidate all fids associated with dentry */
 551		/* NOTE: This will not include open fids */
 552		dentry->d_op->d_release(dentry);
 553	}
 554	return retval;
 555}
 556
 557/**
 558 * v9fs_create - Create a file
 559 * @v9ses: session information
 560 * @dir: directory that dentry is being created in
 561 * @dentry:  dentry that is being created
 562 * @extension: 9p2000.u extension string to support devices, etc.
 563 * @perm: create permissions
 564 * @mode: open mode
 565 *
 566 */
 567static struct p9_fid *
 568v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 569		struct dentry *dentry, char *extension, u32 perm, u8 mode)
 570{
 571	int err;
 572	const unsigned char *name;
 573	struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
 574	struct inode *inode;
 575
 576	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 577
 
 578	name = dentry->d_name.name;
 579	dfid = v9fs_parent_fid(dentry);
 580	if (IS_ERR(dfid)) {
 581		err = PTR_ERR(dfid);
 582		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 583		return ERR_PTR(err);
 584	}
 585
 586	/* clone a fid to use for creation */
 587	ofid = clone_fid(dfid);
 588	if (IS_ERR(ofid)) {
 589		err = PTR_ERR(ofid);
 590		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 591		goto error;
 592	}
 593
 594	err = p9_client_fcreate(ofid, name, perm, mode, extension);
 595	if (err < 0) {
 596		p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 597		goto error;
 598	}
 599
 600	if (!(perm & P9_DMLINK)) {
 601		/* now walk from the parent so we can get unopened fid */
 602		fid = p9_client_walk(dfid, 1, &name, 1);
 603		if (IS_ERR(fid)) {
 604			err = PTR_ERR(fid);
 605			p9_debug(P9_DEBUG_VFS,
 606				   "p9_client_walk failed %d\n", err);
 607			goto error;
 608		}
 609		/*
 610		 * instantiate inode and assign the unopened fid to the dentry
 611		 */
 612		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 613		if (IS_ERR(inode)) {
 614			err = PTR_ERR(inode);
 615			p9_debug(P9_DEBUG_VFS,
 616				   "inode creation failed %d\n", err);
 617			goto error;
 618		}
 619		v9fs_fid_add(dentry, &fid);
 620		d_instantiate(dentry, inode);
 621	}
 622	p9_fid_put(dfid);
 623	return ofid;
 624error:
 625	p9_fid_put(dfid);
 626	p9_fid_put(ofid);
 627	p9_fid_put(fid);
 628	return ERR_PTR(err);
 629}
 630
 631/**
 632 * v9fs_vfs_create - VFS hook to create a regular file
 633 * @idmap: idmap of the mount
 634 * @dir: The parent directory
 635 * @dentry: The name of file to be created
 636 * @mode: The UNIX file mode to set
 637 * @excl: True if the file must not yet exist
 638 *
 639 * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
 640 * for mknod(2).
 641 *
 642 */
 643
 644static int
 645v9fs_vfs_create(struct mnt_idmap *idmap, struct inode *dir,
 646		struct dentry *dentry, umode_t mode, bool excl)
 647{
 648	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
 649	u32 perm = unixmode2p9mode(v9ses, mode);
 650	struct p9_fid *fid;
 651
 652	/* P9_OEXCL? */
 653	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
 654	if (IS_ERR(fid))
 655		return PTR_ERR(fid);
 656
 657	v9fs_invalidate_inode_attr(dir);
 658	p9_fid_put(fid);
 659
 660	return 0;
 661}
 662
 663/**
 664 * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 665 * @idmap: idmap of the mount
 666 * @dir:  inode that is being unlinked
 667 * @dentry: dentry that is being unlinked
 668 * @mode: mode for new directory
 669 *
 670 */
 671
 672static int v9fs_vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 673			  struct dentry *dentry, umode_t mode)
 674{
 675	int err;
 676	u32 perm;
 677	struct p9_fid *fid;
 678	struct v9fs_session_info *v9ses;
 679
 680	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 681	err = 0;
 682	v9ses = v9fs_inode2v9ses(dir);
 683	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 684	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 685	if (IS_ERR(fid)) {
 686		err = PTR_ERR(fid);
 687		fid = NULL;
 688	} else {
 689		inc_nlink(dir);
 690		v9fs_invalidate_inode_attr(dir);
 691	}
 692
 693	if (fid)
 694		p9_fid_put(fid);
 695
 696	return err;
 697}
 698
 699/**
 700 * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 701 * @dir:  inode that is being walked from
 702 * @dentry: dentry that is being walked to?
 703 * @flags: lookup flags (unused)
 704 *
 705 */
 706
 707struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 708				      unsigned int flags)
 709{
 710	struct dentry *res;
 711	struct v9fs_session_info *v9ses;
 712	struct p9_fid *dfid, *fid;
 713	struct inode *inode;
 714	const unsigned char *name;
 715
 716	p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
 717		 dir, dentry, dentry, flags);
 718
 719	if (dentry->d_name.len > NAME_MAX)
 720		return ERR_PTR(-ENAMETOOLONG);
 721
 722	v9ses = v9fs_inode2v9ses(dir);
 723	/* We can walk d_parent because we hold the dir->i_mutex */
 724	dfid = v9fs_parent_fid(dentry);
 725	if (IS_ERR(dfid))
 726		return ERR_CAST(dfid);
 727
 728	/*
 729	 * Make sure we don't use a wrong inode due to parallel
 730	 * unlink. For cached mode create calls request for new
 731	 * inode. But with cache disabled, lookup should do this.
 732	 */
 733	name = dentry->d_name.name;
 734	fid = p9_client_walk(dfid, 1, &name, 1);
 735	p9_fid_put(dfid);
 736	if (fid == ERR_PTR(-ENOENT))
 737		inode = NULL;
 738	else if (IS_ERR(fid))
 739		inode = ERR_CAST(fid);
 740	else if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
 741		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 742	else
 743		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 744	/*
 745	 * If we had a rename on the server and a parallel lookup
 746	 * for the new name, then make sure we instantiate with
 747	 * the new name. ie look up for a/b, while on server somebody
 748	 * moved b under k and client parallely did a lookup for
 749	 * k/b.
 750	 */
 751	res = d_splice_alias(inode, dentry);
 752	if (!IS_ERR(fid)) {
 753		if (!res)
 754			v9fs_fid_add(dentry, &fid);
 755		else if (!IS_ERR(res))
 756			v9fs_fid_add(res, &fid);
 757		else
 758			p9_fid_put(fid);
 759	}
 760	return res;
 761}
 762
 763static int
 764v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 765		     struct file *file, unsigned int flags, umode_t mode)
 766{
 767	int err;
 768	u32 perm;
 769	struct v9fs_inode __maybe_unused *v9inode;
 770	struct v9fs_session_info *v9ses;
 771	struct p9_fid *fid;
 772	struct dentry *res = NULL;
 773	struct inode *inode;
 774	int p9_omode;
 775
 776	if (d_in_lookup(dentry)) {
 777		res = v9fs_vfs_lookup(dir, dentry, 0);
 778		if (IS_ERR(res))
 779			return PTR_ERR(res);
 780
 781		if (res)
 782			dentry = res;
 783	}
 784
 785	/* Only creates */
 786	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
 787		return finish_no_open(file, res);
 788
 
 
 789	v9ses = v9fs_inode2v9ses(dir);
 790	perm = unixmode2p9mode(v9ses, mode);
 791	p9_omode = v9fs_uflags2omode(flags, v9fs_proto_dotu(v9ses));
 792
 793	if ((v9ses->cache & CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
 794		p9_omode = (p9_omode & ~P9_OWRITE) | P9_ORDWR;
 795		p9_debug(P9_DEBUG_CACHE,
 796			"write-only file with writeback enabled, creating w/ O_RDWR\n");
 797	}
 798	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, p9_omode);
 799	if (IS_ERR(fid)) {
 800		err = PTR_ERR(fid);
 801		goto error;
 802	}
 803
 804	v9fs_invalidate_inode_attr(dir);
 805	inode = d_inode(dentry);
 806	v9inode = V9FS_I(inode);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 807	err = finish_open(file, dentry, generic_file_open);
 808	if (err)
 809		goto error;
 810
 811	file->private_data = fid;
 812#ifdef CONFIG_9P_FSCACHE
 813	if (v9ses->cache & CACHE_FSCACHE)
 814		fscache_use_cookie(v9fs_inode_cookie(v9inode),
 815				   file->f_mode & FMODE_WRITE);
 816#endif
 817
 818	v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
 819	v9fs_open_fid_add(inode, &fid);
 820
 821	file->f_mode |= FMODE_CREATED;
 822out:
 823	dput(res);
 824	return err;
 825
 826error:
 827	p9_fid_put(fid);
 828	goto out;
 829}
 830
 831/**
 832 * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 833 * @i:  inode that is being unlinked
 834 * @d: dentry that is being unlinked
 835 *
 836 */
 837
 838int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 839{
 840	return v9fs_remove(i, d, 0);
 841}
 842
 843/**
 844 * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 845 * @i:  inode that is being unlinked
 846 * @d: dentry that is being unlinked
 847 *
 848 */
 849
 850int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 851{
 852	return v9fs_remove(i, d, AT_REMOVEDIR);
 853}
 854
 855/**
 856 * v9fs_vfs_rename - VFS hook to rename an inode
 857 * @idmap: The idmap of the mount
 858 * @old_dir:  old dir inode
 859 * @old_dentry: old dentry
 860 * @new_dir: new dir inode
 861 * @new_dentry: new dentry
 862 * @flags: RENAME_* flags
 863 *
 864 */
 865
 866int
 867v9fs_vfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 868		struct dentry *old_dentry, struct inode *new_dir,
 869		struct dentry *new_dentry, unsigned int flags)
 870{
 871	int retval;
 872	struct inode *old_inode;
 873	struct inode *new_inode;
 874	struct v9fs_session_info *v9ses;
 875	struct p9_fid *oldfid = NULL, *dfid = NULL;
 876	struct p9_fid *olddirfid = NULL;
 877	struct p9_fid *newdirfid = NULL;
 878	struct p9_wstat wstat;
 879
 880	if (flags)
 881		return -EINVAL;
 882
 883	p9_debug(P9_DEBUG_VFS, "\n");
 
 884	old_inode = d_inode(old_dentry);
 885	new_inode = d_inode(new_dentry);
 886	v9ses = v9fs_inode2v9ses(old_inode);
 887	oldfid = v9fs_fid_lookup(old_dentry);
 888	if (IS_ERR(oldfid))
 889		return PTR_ERR(oldfid);
 890
 891	dfid = v9fs_parent_fid(old_dentry);
 892	olddirfid = clone_fid(dfid);
 893	p9_fid_put(dfid);
 894	dfid = NULL;
 895
 896	if (IS_ERR(olddirfid)) {
 897		retval = PTR_ERR(olddirfid);
 898		goto error;
 899	}
 900
 901	dfid = v9fs_parent_fid(new_dentry);
 902	newdirfid = clone_fid(dfid);
 903	p9_fid_put(dfid);
 904	dfid = NULL;
 905
 906	if (IS_ERR(newdirfid)) {
 907		retval = PTR_ERR(newdirfid);
 908		goto error;
 909	}
 910
 911	down_write(&v9ses->rename_sem);
 912	if (v9fs_proto_dotl(v9ses)) {
 913		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
 914					    newdirfid, new_dentry->d_name.name);
 915		if (retval == -EOPNOTSUPP)
 916			retval = p9_client_rename(oldfid, newdirfid,
 917						  new_dentry->d_name.name);
 918		if (retval != -EOPNOTSUPP)
 919			goto error_locked;
 920	}
 921	if (old_dentry->d_parent != new_dentry->d_parent) {
 922		/*
 923		 * 9P .u can only handle file rename in the same directory
 924		 */
 925
 926		p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
 927		retval = -EXDEV;
 928		goto error_locked;
 929	}
 930	v9fs_blank_wstat(&wstat);
 931	wstat.muid = v9ses->uname;
 932	wstat.name = new_dentry->d_name.name;
 933	retval = p9_client_wstat(oldfid, &wstat);
 934
 935error_locked:
 936	if (!retval) {
 937		if (new_inode) {
 938			if (S_ISDIR(new_inode->i_mode))
 939				clear_nlink(new_inode);
 940			else
 941				v9fs_dec_count(new_inode);
 942		}
 943		if (S_ISDIR(old_inode->i_mode)) {
 944			if (!new_inode)
 945				inc_nlink(new_dir);
 946			v9fs_dec_count(old_dir);
 947		}
 948		v9fs_invalidate_inode_attr(old_inode);
 949		v9fs_invalidate_inode_attr(old_dir);
 950		v9fs_invalidate_inode_attr(new_dir);
 951
 952		/* successful rename */
 953		d_move(old_dentry, new_dentry);
 954	}
 955	up_write(&v9ses->rename_sem);
 956
 957error:
 958	p9_fid_put(newdirfid);
 959	p9_fid_put(olddirfid);
 960	p9_fid_put(oldfid);
 961	return retval;
 962}
 963
 964/**
 965 * v9fs_vfs_getattr - retrieve file metadata
 966 * @idmap: idmap of the mount
 967 * @path: Object to query
 968 * @stat: metadata structure to populate
 969 * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
 970 * @flags: AT_STATX_xxx setting
 971 *
 972 */
 973
 974static int
 975v9fs_vfs_getattr(struct mnt_idmap *idmap, const struct path *path,
 976		 struct kstat *stat, u32 request_mask, unsigned int flags)
 977{
 978	struct dentry *dentry = path->dentry;
 979	struct inode *inode = d_inode(dentry);
 980	struct v9fs_session_info *v9ses;
 981	struct p9_fid *fid;
 982	struct p9_wstat *st;
 983
 984	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
 985	v9ses = v9fs_dentry2v9ses(dentry);
 986	if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
 987		generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
 988		return 0;
 989	} else if (v9ses->cache & CACHE_WRITEBACK) {
 990		if (S_ISREG(inode->i_mode)) {
 991			int retval = filemap_fdatawrite(inode->i_mapping);
 992
 993			if (retval)
 994				p9_debug(P9_DEBUG_ERROR,
 995				    "flushing writeback during getattr returned %d\n", retval);
 996		}
 997	}
 998	fid = v9fs_fid_lookup(dentry);
 999	if (IS_ERR(fid))
1000		return PTR_ERR(fid);
1001
1002	st = p9_client_stat(fid);
1003	p9_fid_put(fid);
1004	if (IS_ERR(st))
1005		return PTR_ERR(st);
1006
1007	v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
1008	generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), stat);
1009
1010	p9stat_free(st);
1011	kfree(st);
1012	return 0;
1013}
1014
1015/**
1016 * v9fs_vfs_setattr - set file metadata
1017 * @idmap: idmap of the mount
1018 * @dentry: file whose metadata to set
1019 * @iattr: metadata assignment structure
1020 *
1021 */
1022
1023static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
1024			    struct dentry *dentry, struct iattr *iattr)
1025{
1026	int retval, use_dentry = 0;
1027	struct inode *inode = d_inode(dentry);
 
1028	struct v9fs_session_info *v9ses;
1029	struct p9_fid *fid = NULL;
1030	struct p9_wstat wstat;
1031
1032	p9_debug(P9_DEBUG_VFS, "\n");
1033	retval = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
1034	if (retval)
1035		return retval;
1036
 
1037	v9ses = v9fs_dentry2v9ses(dentry);
1038	if (iattr->ia_valid & ATTR_FILE) {
1039		fid = iattr->ia_file->private_data;
1040		WARN_ON(!fid);
1041	}
1042	if (!fid) {
1043		fid = v9fs_fid_lookup(dentry);
1044		use_dentry = 1;
1045	}
1046	if (IS_ERR(fid))
1047		return PTR_ERR(fid);
1048
1049	v9fs_blank_wstat(&wstat);
1050	if (iattr->ia_valid & ATTR_MODE)
1051		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1052
1053	if (iattr->ia_valid & ATTR_MTIME)
1054		wstat.mtime = iattr->ia_mtime.tv_sec;
1055
1056	if (iattr->ia_valid & ATTR_ATIME)
1057		wstat.atime = iattr->ia_atime.tv_sec;
1058
1059	if (iattr->ia_valid & ATTR_SIZE)
1060		wstat.length = iattr->ia_size;
1061
1062	if (v9fs_proto_dotu(v9ses)) {
1063		if (iattr->ia_valid & ATTR_UID)
1064			wstat.n_uid = iattr->ia_uid;
1065
1066		if (iattr->ia_valid & ATTR_GID)
1067			wstat.n_gid = iattr->ia_gid;
1068	}
1069
1070	/* Write all dirty data */
1071	if (d_is_reg(dentry)) {
1072		retval = filemap_fdatawrite(inode->i_mapping);
1073		if (retval)
1074			p9_debug(P9_DEBUG_ERROR,
1075			    "flushing writeback during setattr returned %d\n", retval);
1076	}
1077
1078	retval = p9_client_wstat(fid, &wstat);
1079
1080	if (use_dentry)
1081		p9_fid_put(fid);
1082
1083	if (retval < 0)
1084		return retval;
1085
1086	if ((iattr->ia_valid & ATTR_SIZE) &&
1087		 iattr->ia_size != i_size_read(inode)) {
1088		truncate_setsize(inode, iattr->ia_size);
1089		netfs_resize_file(netfs_inode(inode), iattr->ia_size, true);
1090
1091#ifdef CONFIG_9P_FSCACHE
1092		if (v9ses->cache & CACHE_FSCACHE) {
1093			struct v9fs_inode *v9inode = V9FS_I(inode);
1094
1095			fscache_resize_cookie(v9fs_inode_cookie(v9inode), iattr->ia_size);
1096		}
1097#endif
1098	}
1099
1100	v9fs_invalidate_inode_attr(inode);
1101
1102	setattr_copy(&nop_mnt_idmap, inode, iattr);
1103	mark_inode_dirty(inode);
1104	return 0;
1105}
1106
1107/**
1108 * v9fs_stat2inode - populate an inode structure with mistat info
1109 * @stat: Plan 9 metadata (mistat) structure
1110 * @inode: inode to populate
1111 * @sb: superblock of filesystem
1112 * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1113 *
1114 */
1115
1116void
1117v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1118		 struct super_block *sb, unsigned int flags)
1119{
1120	umode_t mode;
1121	struct v9fs_session_info *v9ses = sb->s_fs_info;
1122	struct v9fs_inode *v9inode = V9FS_I(inode);
1123
1124	inode_set_atime(inode, stat->atime, 0);
1125	inode_set_mtime(inode, stat->mtime, 0);
1126	inode_set_ctime(inode, stat->mtime, 0);
 
 
1127
1128	inode->i_uid = v9ses->dfltuid;
1129	inode->i_gid = v9ses->dfltgid;
1130
1131	if (v9fs_proto_dotu(v9ses)) {
1132		inode->i_uid = stat->n_uid;
1133		inode->i_gid = stat->n_gid;
1134	}
1135	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1136		if (v9fs_proto_dotu(v9ses)) {
1137			unsigned int i_nlink;
1138			/*
1139			 * Hadlink support got added later to the .u extension.
1140			 * So there can be a server out there that doesn't
1141			 * support this even with .u extension. That would
1142			 * just leave us with stat->extension being an empty
1143			 * string, though.
1144			 */
1145			/* HARDLINKCOUNT %u */
1146			if (sscanf(stat->extension,
1147				   " HARDLINKCOUNT %u", &i_nlink) == 1)
1148				set_nlink(inode, i_nlink);
1149		}
1150	}
1151	mode = p9mode2perm(v9ses, stat);
1152	mode |= inode->i_mode & ~S_IALLUGO;
1153	inode->i_mode = mode;
1154
1155	v9inode->netfs.remote_i_size = stat->length;
1156	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1157		v9fs_i_size_write(inode, stat->length);
1158	/* not real number of blocks, but 512 byte ones ... */
1159	inode->i_blocks = (stat->length + 512 - 1) >> 9;
1160	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1161}
1162
1163/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1164 * v9fs_vfs_get_link - follow a symlink path
1165 * @dentry: dentry for symlink
1166 * @inode: inode for symlink
1167 * @done: delayed call for when we are done with the return value
1168 */
1169
1170static const char *v9fs_vfs_get_link(struct dentry *dentry,
1171				     struct inode *inode,
1172				     struct delayed_call *done)
1173{
1174	struct v9fs_session_info *v9ses;
1175	struct p9_fid *fid;
1176	struct p9_wstat *st;
1177	char *res;
1178
1179	if (!dentry)
1180		return ERR_PTR(-ECHILD);
1181
1182	v9ses = v9fs_dentry2v9ses(dentry);
1183	if (!v9fs_proto_dotu(v9ses))
1184		return ERR_PTR(-EBADF);
1185
1186	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1187	fid = v9fs_fid_lookup(dentry);
1188
1189	if (IS_ERR(fid))
1190		return ERR_CAST(fid);
1191
1192	st = p9_client_stat(fid);
1193	p9_fid_put(fid);
1194	if (IS_ERR(st))
1195		return ERR_CAST(st);
1196
1197	if (!(st->mode & P9_DMSYMLINK)) {
1198		p9stat_free(st);
1199		kfree(st);
1200		return ERR_PTR(-EINVAL);
1201	}
1202	res = st->extension;
1203	st->extension = NULL;
1204	if (strlen(res) >= PATH_MAX)
1205		res[PATH_MAX - 1] = '\0';
1206
1207	p9stat_free(st);
1208	kfree(st);
1209	set_delayed_call(done, kfree_link, res);
1210	return res;
1211}
1212
1213/**
1214 * v9fs_vfs_mkspecial - create a special file
1215 * @dir: inode to create special file in
1216 * @dentry: dentry to create
1217 * @perm: mode to create special file
1218 * @extension: 9p2000.u format extension string representing special file
1219 *
1220 */
1221
1222static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1223	u32 perm, const char *extension)
1224{
1225	struct p9_fid *fid;
1226	struct v9fs_session_info *v9ses;
1227
1228	v9ses = v9fs_inode2v9ses(dir);
1229	if (!v9fs_proto_dotu(v9ses)) {
1230		p9_debug(P9_DEBUG_ERROR, "not extended\n");
1231		return -EPERM;
1232	}
1233
1234	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1235								P9_OREAD);
1236	if (IS_ERR(fid))
1237		return PTR_ERR(fid);
1238
1239	v9fs_invalidate_inode_attr(dir);
1240	p9_fid_put(fid);
1241	return 0;
1242}
1243
1244/**
1245 * v9fs_vfs_symlink - helper function to create symlinks
1246 * @idmap: idmap of the mount
1247 * @dir: directory inode containing symlink
1248 * @dentry: dentry for symlink
1249 * @symname: symlink data
1250 *
1251 * See Also: 9P2000.u RFC for more information
1252 *
1253 */
1254
1255static int
1256v9fs_vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
1257		 struct dentry *dentry, const char *symname)
1258{
1259	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1260		 dir->i_ino, dentry, symname);
1261
1262	return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1263}
1264
1265#define U32_MAX_DIGITS 10
1266
1267/**
1268 * v9fs_vfs_link - create a hardlink
1269 * @old_dentry: dentry for file to link to
1270 * @dir: inode destination for new link
1271 * @dentry: dentry for link
1272 *
1273 */
1274
1275static int
1276v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1277	      struct dentry *dentry)
1278{
1279	int retval;
1280	char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1281	struct p9_fid *oldfid;
1282
1283	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1284		 dir->i_ino, dentry, old_dentry);
1285
1286	oldfid = v9fs_fid_clone(old_dentry);
1287	if (IS_ERR(oldfid))
1288		return PTR_ERR(oldfid);
1289
1290	sprintf(name, "%d\n", oldfid->fid);
1291	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1292	if (!retval) {
1293		v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1294		v9fs_invalidate_inode_attr(dir);
1295	}
1296	p9_fid_put(oldfid);
1297	return retval;
1298}
1299
1300/**
1301 * v9fs_vfs_mknod - create a special file
1302 * @idmap: idmap of the mount
1303 * @dir: inode destination for new link
1304 * @dentry: dentry for file
1305 * @mode: mode for creation
1306 * @rdev: device associated with special file
1307 *
1308 */
1309
1310static int
1311v9fs_vfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
1312	       struct dentry *dentry, umode_t mode, dev_t rdev)
1313{
1314	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1315	int retval;
1316	char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1317	u32 perm;
1318
1319	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %x MAJOR: %u MINOR: %u\n",
1320		 dir->i_ino, dentry, mode,
1321		 MAJOR(rdev), MINOR(rdev));
1322
1323	/* build extension */
1324	if (S_ISBLK(mode))
1325		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1326	else if (S_ISCHR(mode))
1327		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1328	else
1329		*name = 0;
1330
1331	perm = unixmode2p9mode(v9ses, mode);
1332	retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1333
1334	return retval;
1335}
1336
1337int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1338{
1339	int umode;
1340	dev_t rdev;
1341	struct p9_wstat *st;
1342	struct v9fs_session_info *v9ses;
1343	unsigned int flags;
1344
1345	v9ses = v9fs_inode2v9ses(inode);
1346	st = p9_client_stat(fid);
1347	if (IS_ERR(st))
1348		return PTR_ERR(st);
1349	/*
1350	 * Don't update inode if the file type is different
1351	 */
1352	umode = p9mode2unixmode(v9ses, st, &rdev);
1353	if (inode_wrong_type(inode, umode))
1354		goto out;
1355
1356	/*
1357	 * We don't want to refresh inode->i_size,
1358	 * because we may have cached data
1359	 */
1360	flags = (v9ses->cache & CACHE_LOOSE) ?
1361		V9FS_STAT2INODE_KEEP_ISIZE : 0;
1362	v9fs_stat2inode(st, inode, inode->i_sb, flags);
1363out:
1364	p9stat_free(st);
1365	kfree(st);
1366	return 0;
1367}
1368
1369static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1370	.create = v9fs_vfs_create,
1371	.lookup = v9fs_vfs_lookup,
1372	.atomic_open = v9fs_vfs_atomic_open,
1373	.symlink = v9fs_vfs_symlink,
1374	.link = v9fs_vfs_link,
1375	.unlink = v9fs_vfs_unlink,
1376	.mkdir = v9fs_vfs_mkdir,
1377	.rmdir = v9fs_vfs_rmdir,
1378	.mknod = v9fs_vfs_mknod,
1379	.rename = v9fs_vfs_rename,
1380	.getattr = v9fs_vfs_getattr,
1381	.setattr = v9fs_vfs_setattr,
1382};
1383
1384static const struct inode_operations v9fs_dir_inode_operations = {
1385	.create = v9fs_vfs_create,
1386	.lookup = v9fs_vfs_lookup,
1387	.atomic_open = v9fs_vfs_atomic_open,
1388	.unlink = v9fs_vfs_unlink,
1389	.mkdir = v9fs_vfs_mkdir,
1390	.rmdir = v9fs_vfs_rmdir,
1391	.mknod = v9fs_vfs_mknod,
1392	.rename = v9fs_vfs_rename,
1393	.getattr = v9fs_vfs_getattr,
1394	.setattr = v9fs_vfs_setattr,
1395};
1396
1397static const struct inode_operations v9fs_file_inode_operations = {
1398	.getattr = v9fs_vfs_getattr,
1399	.setattr = v9fs_vfs_setattr,
1400};
1401
1402static const struct inode_operations v9fs_symlink_inode_operations = {
1403	.get_link = v9fs_vfs_get_link,
1404	.getattr = v9fs_vfs_getattr,
1405	.setattr = v9fs_vfs_setattr,
1406};
1407