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   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
   1/*
   2 *  linux/fs/9p/vfs_inode.c
   3 *
   4 * This file contains vfs inode ops for the 9P2000 protocol.
   5 *
   6 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   7 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   8 *
   9 *  This program is free software; you can redistribute it and/or modify
  10 *  it under the terms of the GNU General Public License version 2
  11 *  as published by the Free Software Foundation.
  12 *
  13 *  This program is distributed in the hope that it will be useful,
  14 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 *  GNU General Public License for more details.
  17 *
  18 *  You should have received a copy of the GNU General Public License
  19 *  along with this program; if not, write to:
  20 *  Free Software Foundation
  21 *  51 Franklin Street, Fifth Floor
  22 *  Boston, MA  02111-1301  USA
  23 *
  24 */
  25
  26#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  27
  28#include <linux/module.h>
  29#include <linux/errno.h>
  30#include <linux/fs.h>
  31#include <linux/file.h>
  32#include <linux/pagemap.h>
  33#include <linux/stat.h>
  34#include <linux/string.h>
  35#include <linux/inet.h>
  36#include <linux/namei.h>
  37#include <linux/idr.h>
  38#include <linux/sched.h>
  39#include <linux/slab.h>
  40#include <linux/xattr.h>
  41#include <linux/posix_acl.h>
  42#include <net/9p/9p.h>
  43#include <net/9p/client.h>
  44
  45#include "v9fs.h"
  46#include "v9fs_vfs.h"
  47#include "fid.h"
  48#include "cache.h"
  49#include "xattr.h"
  50#include "acl.h"
  51
  52static const struct inode_operations v9fs_dir_inode_operations;
  53static const struct inode_operations v9fs_dir_inode_operations_dotu;
  54static const struct inode_operations v9fs_file_inode_operations;
  55static const struct inode_operations v9fs_symlink_inode_operations;
  56
  57/**
  58 * unixmode2p9mode - convert unix mode bits to plan 9
  59 * @v9ses: v9fs session information
  60 * @mode: mode to convert
  61 *
  62 */
  63
  64static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
  65{
  66	int res;
  67	res = mode & 0777;
  68	if (S_ISDIR(mode))
  69		res |= P9_DMDIR;
  70	if (v9fs_proto_dotu(v9ses)) {
  71		if (v9ses->nodev == 0) {
  72			if (S_ISSOCK(mode))
  73				res |= P9_DMSOCKET;
  74			if (S_ISFIFO(mode))
  75				res |= P9_DMNAMEDPIPE;
  76			if (S_ISBLK(mode))
  77				res |= P9_DMDEVICE;
  78			if (S_ISCHR(mode))
  79				res |= P9_DMDEVICE;
  80		}
  81
  82		if ((mode & S_ISUID) == S_ISUID)
  83			res |= P9_DMSETUID;
  84		if ((mode & S_ISGID) == S_ISGID)
  85			res |= P9_DMSETGID;
  86		if ((mode & S_ISVTX) == S_ISVTX)
  87			res |= P9_DMSETVTX;
  88	}
  89	return res;
  90}
  91
  92/**
  93 * p9mode2perm- convert plan9 mode bits to unix permission bits
  94 * @v9ses: v9fs session information
  95 * @stat: p9_wstat from which mode need to be derived
  96 *
  97 */
  98static int p9mode2perm(struct v9fs_session_info *v9ses,
  99		       struct p9_wstat *stat)
 100{
 101	int res;
 102	int mode = stat->mode;
 103
 104	res = mode & S_IALLUGO;
 105	if (v9fs_proto_dotu(v9ses)) {
 106		if ((mode & P9_DMSETUID) == P9_DMSETUID)
 107			res |= S_ISUID;
 108
 109		if ((mode & P9_DMSETGID) == P9_DMSETGID)
 110			res |= S_ISGID;
 111
 112		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
 113			res |= S_ISVTX;
 114	}
 115	return res;
 116}
 117
 118/**
 119 * p9mode2unixmode- convert plan9 mode bits to unix mode bits
 120 * @v9ses: v9fs session information
 121 * @stat: p9_wstat from which mode need to be derived
 122 * @rdev: major number, minor number in case of device files.
 123 *
 124 */
 125static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
 126			       struct p9_wstat *stat, dev_t *rdev)
 127{
 128	int res;
 129	u32 mode = stat->mode;
 130
 131	*rdev = 0;
 132	res = p9mode2perm(v9ses, stat);
 133
 134	if ((mode & P9_DMDIR) == P9_DMDIR)
 135		res |= S_IFDIR;
 136	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
 137		res |= S_IFLNK;
 138	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
 139		 && (v9ses->nodev == 0))
 140		res |= S_IFSOCK;
 141	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
 142		 && (v9ses->nodev == 0))
 143		res |= S_IFIFO;
 144	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 145		 && (v9ses->nodev == 0)) {
 146		char type = 0, ext[32];
 147		int major = -1, minor = -1;
 148
 149		strlcpy(ext, stat->extension, sizeof(ext));
 150		sscanf(ext, "%c %i %i", &type, &major, &minor);
 151		switch (type) {
 152		case 'c':
 153			res |= S_IFCHR;
 154			break;
 155		case 'b':
 156			res |= S_IFBLK;
 157			break;
 158		default:
 159			p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
 160				 type, stat->extension);
 161		};
 162		*rdev = MKDEV(major, minor);
 163	} else
 164		res |= S_IFREG;
 165
 166	return res;
 167}
 168
 169/**
 170 * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 171 * @uflags: flags to convert
 172 * @extended: if .u extensions are active
 173 */
 174
 175int v9fs_uflags2omode(int uflags, int extended)
 176{
 177	int ret;
 178
 179	ret = 0;
 180	switch (uflags&3) {
 181	default:
 182	case O_RDONLY:
 183		ret = P9_OREAD;
 184		break;
 185
 186	case O_WRONLY:
 187		ret = P9_OWRITE;
 188		break;
 189
 190	case O_RDWR:
 191		ret = P9_ORDWR;
 192		break;
 193	}
 194
 195	if (extended) {
 196		if (uflags & O_EXCL)
 197			ret |= P9_OEXCL;
 198
 199		if (uflags & O_APPEND)
 200			ret |= P9_OAPPEND;
 201	}
 202
 203	return ret;
 204}
 205
 206/**
 207 * v9fs_blank_wstat - helper function to setup a 9P stat structure
 208 * @wstat: structure to initialize
 209 *
 210 */
 211
 212void
 213v9fs_blank_wstat(struct p9_wstat *wstat)
 214{
 215	wstat->type = ~0;
 216	wstat->dev = ~0;
 217	wstat->qid.type = ~0;
 218	wstat->qid.version = ~0;
 219	*((long long *)&wstat->qid.path) = ~0;
 220	wstat->mode = ~0;
 221	wstat->atime = ~0;
 222	wstat->mtime = ~0;
 223	wstat->length = ~0;
 224	wstat->name = NULL;
 225	wstat->uid = NULL;
 226	wstat->gid = NULL;
 227	wstat->muid = NULL;
 228	wstat->n_uid = INVALID_UID;
 229	wstat->n_gid = INVALID_GID;
 230	wstat->n_muid = INVALID_UID;
 231	wstat->extension = NULL;
 232}
 233
 234/**
 235 * v9fs_alloc_inode - helper function to allocate an inode
 236 *
 237 */
 238struct inode *v9fs_alloc_inode(struct super_block *sb)
 239{
 240	struct v9fs_inode *v9inode;
 241	v9inode = (struct v9fs_inode *)kmem_cache_alloc(v9fs_inode_cache,
 242							GFP_KERNEL);
 243	if (!v9inode)
 244		return NULL;
 245#ifdef CONFIG_9P_FSCACHE
 246	v9inode->fscache = NULL;
 247	mutex_init(&v9inode->fscache_lock);
 248#endif
 249	v9inode->writeback_fid = NULL;
 250	v9inode->cache_validity = 0;
 251	mutex_init(&v9inode->v_mutex);
 252	return &v9inode->vfs_inode;
 253}
 254
 255/**
 256 * v9fs_destroy_inode - destroy an inode
 257 *
 258 */
 259
 260static void v9fs_i_callback(struct rcu_head *head)
 261{
 262	struct inode *inode = container_of(head, struct inode, i_rcu);
 263	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
 264}
 265
 266void v9fs_destroy_inode(struct inode *inode)
 267{
 268	call_rcu(&inode->i_rcu, v9fs_i_callback);
 269}
 270
 271int v9fs_init_inode(struct v9fs_session_info *v9ses,
 272		    struct inode *inode, umode_t mode, dev_t rdev)
 273{
 274	int err = 0;
 275
 276	inode_init_owner(inode, NULL, mode);
 277	inode->i_blocks = 0;
 278	inode->i_rdev = rdev;
 279	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 280	inode->i_mapping->a_ops = &v9fs_addr_operations;
 281
 282	switch (mode & S_IFMT) {
 283	case S_IFIFO:
 284	case S_IFBLK:
 285	case S_IFCHR:
 286	case S_IFSOCK:
 287		if (v9fs_proto_dotl(v9ses)) {
 288			inode->i_op = &v9fs_file_inode_operations_dotl;
 289		} else if (v9fs_proto_dotu(v9ses)) {
 290			inode->i_op = &v9fs_file_inode_operations;
 291		} else {
 292			p9_debug(P9_DEBUG_ERROR,
 293				 "special files without extended mode\n");
 294			err = -EINVAL;
 295			goto error;
 296		}
 297		init_special_inode(inode, inode->i_mode, inode->i_rdev);
 298		break;
 299	case S_IFREG:
 300		if (v9fs_proto_dotl(v9ses)) {
 301			inode->i_op = &v9fs_file_inode_operations_dotl;
 302			if (v9ses->cache == CACHE_LOOSE ||
 303			    v9ses->cache == CACHE_FSCACHE)
 304				inode->i_fop =
 305					&v9fs_cached_file_operations_dotl;
 306			else if (v9ses->cache == CACHE_MMAP)
 307				inode->i_fop = &v9fs_mmap_file_operations_dotl;
 308			else
 309				inode->i_fop = &v9fs_file_operations_dotl;
 310		} else {
 311			inode->i_op = &v9fs_file_inode_operations;
 312			if (v9ses->cache == CACHE_LOOSE ||
 313			    v9ses->cache == CACHE_FSCACHE)
 314				inode->i_fop =
 315					&v9fs_cached_file_operations;
 316			else if (v9ses->cache == CACHE_MMAP)
 317				inode->i_fop = &v9fs_mmap_file_operations;
 318			else
 319				inode->i_fop = &v9fs_file_operations;
 320		}
 321
 322		break;
 323	case S_IFLNK:
 324		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 325			p9_debug(P9_DEBUG_ERROR,
 326				 "extended modes used with legacy protocol\n");
 327			err = -EINVAL;
 328			goto error;
 329		}
 330
 331		if (v9fs_proto_dotl(v9ses))
 332			inode->i_op = &v9fs_symlink_inode_operations_dotl;
 333		else
 334			inode->i_op = &v9fs_symlink_inode_operations;
 335
 336		break;
 337	case S_IFDIR:
 338		inc_nlink(inode);
 339		if (v9fs_proto_dotl(v9ses))
 340			inode->i_op = &v9fs_dir_inode_operations_dotl;
 341		else if (v9fs_proto_dotu(v9ses))
 342			inode->i_op = &v9fs_dir_inode_operations_dotu;
 343		else
 344			inode->i_op = &v9fs_dir_inode_operations;
 345
 346		if (v9fs_proto_dotl(v9ses))
 347			inode->i_fop = &v9fs_dir_operations_dotl;
 348		else
 349			inode->i_fop = &v9fs_dir_operations;
 350
 351		break;
 352	default:
 353		p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
 354			 mode, mode & S_IFMT);
 355		err = -EINVAL;
 356		goto error;
 357	}
 358error:
 359	return err;
 360
 361}
 362
 363/**
 364 * v9fs_get_inode - helper function to setup an inode
 365 * @sb: superblock
 366 * @mode: mode to setup inode with
 367 *
 368 */
 369
 370struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t rdev)
 371{
 372	int err;
 373	struct inode *inode;
 374	struct v9fs_session_info *v9ses = sb->s_fs_info;
 375
 376	p9_debug(P9_DEBUG_VFS, "super block: %p mode: %ho\n", sb, mode);
 377
 378	inode = new_inode(sb);
 379	if (!inode) {
 380		pr_warn("%s (%d): Problem allocating inode\n",
 381			__func__, task_pid_nr(current));
 382		return ERR_PTR(-ENOMEM);
 383	}
 384	err = v9fs_init_inode(v9ses, inode, mode, rdev);
 385	if (err) {
 386		iput(inode);
 387		return ERR_PTR(err);
 388	}
 389	return inode;
 390}
 391
 392/*
 393static struct v9fs_fid*
 394v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
 395{
 396	int err;
 397	int nfid;
 398	struct v9fs_fid *ret;
 399	struct v9fs_fcall *fcall;
 400
 401	nfid = v9fs_get_idpool(&v9ses->fidpool);
 402	if (nfid < 0) {
 403		eprintk(KERN_WARNING, "no free fids available\n");
 404		return ERR_PTR(-ENOSPC);
 405	}
 406
 407	err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
 408		&fcall);
 409
 410	if (err < 0) {
 411		if (fcall && fcall->id == RWALK)
 412			goto clunk_fid;
 413
 414		PRINT_FCALL_ERROR("walk error", fcall);
 415		v9fs_put_idpool(nfid, &v9ses->fidpool);
 416		goto error;
 417	}
 418
 419	kfree(fcall);
 420	fcall = NULL;
 421	ret = v9fs_fid_create(v9ses, nfid);
 422	if (!ret) {
 423		err = -ENOMEM;
 424		goto clunk_fid;
 425	}
 426
 427	err = v9fs_fid_insert(ret, dentry);
 428	if (err < 0) {
 429		v9fs_fid_destroy(ret);
 430		goto clunk_fid;
 431	}
 432
 433	return ret;
 434
 435clunk_fid:
 436	v9fs_t_clunk(v9ses, nfid);
 437
 438error:
 439	kfree(fcall);
 440	return ERR_PTR(err);
 441}
 442*/
 443
 444
 445/**
 446 * v9fs_clear_inode - release an inode
 447 * @inode: inode to release
 448 *
 449 */
 450void v9fs_evict_inode(struct inode *inode)
 451{
 452	struct v9fs_inode *v9inode = V9FS_I(inode);
 453
 454	truncate_inode_pages_final(&inode->i_data);
 455	clear_inode(inode);
 456	filemap_fdatawrite(&inode->i_data);
 457
 458	v9fs_cache_inode_put_cookie(inode);
 459	/* clunk the fid stashed in writeback_fid */
 460	if (v9inode->writeback_fid) {
 461		p9_client_clunk(v9inode->writeback_fid);
 462		v9inode->writeback_fid = NULL;
 463	}
 464}
 465
 466static int v9fs_test_inode(struct inode *inode, void *data)
 467{
 468	int umode;
 469	dev_t rdev;
 470	struct v9fs_inode *v9inode = V9FS_I(inode);
 471	struct p9_wstat *st = (struct p9_wstat *)data;
 472	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 473
 474	umode = p9mode2unixmode(v9ses, st, &rdev);
 475	/* don't match inode of different type */
 476	if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
 477		return 0;
 478
 479	/* compare qid details */
 480	if (memcmp(&v9inode->qid.version,
 481		   &st->qid.version, sizeof(v9inode->qid.version)))
 482		return 0;
 483
 484	if (v9inode->qid.type != st->qid.type)
 485		return 0;
 486	return 1;
 487}
 488
 489static int v9fs_test_new_inode(struct inode *inode, void *data)
 490{
 491	return 0;
 492}
 493
 494static int v9fs_set_inode(struct inode *inode,  void *data)
 495{
 496	struct v9fs_inode *v9inode = V9FS_I(inode);
 497	struct p9_wstat *st = (struct p9_wstat *)data;
 498
 499	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
 500	return 0;
 501}
 502
 503static struct inode *v9fs_qid_iget(struct super_block *sb,
 504				   struct p9_qid *qid,
 505				   struct p9_wstat *st,
 506				   int new)
 507{
 508	dev_t rdev;
 509	int retval;
 510	umode_t umode;
 511	unsigned long i_ino;
 512	struct inode *inode;
 513	struct v9fs_session_info *v9ses = sb->s_fs_info;
 514	int (*test)(struct inode *, void *);
 515
 516	if (new)
 517		test = v9fs_test_new_inode;
 518	else
 519		test = v9fs_test_inode;
 520
 521	i_ino = v9fs_qid2ino(qid);
 522	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
 523	if (!inode)
 524		return ERR_PTR(-ENOMEM);
 525	if (!(inode->i_state & I_NEW))
 526		return inode;
 527	/*
 528	 * initialize the inode with the stat info
 529	 * FIXME!! we may need support for stale inodes
 530	 * later.
 531	 */
 532	inode->i_ino = i_ino;
 533	umode = p9mode2unixmode(v9ses, st, &rdev);
 534	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 535	if (retval)
 536		goto error;
 537
 538	v9fs_stat2inode(st, inode, sb);
 539	v9fs_cache_inode_get_cookie(inode);
 540	unlock_new_inode(inode);
 541	return inode;
 542error:
 543	iget_failed(inode);
 544	return ERR_PTR(retval);
 545
 546}
 547
 548struct inode *
 549v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 550		    struct super_block *sb, int new)
 551{
 552	struct p9_wstat *st;
 553	struct inode *inode = NULL;
 554
 555	st = p9_client_stat(fid);
 556	if (IS_ERR(st))
 557		return ERR_CAST(st);
 558
 559	inode = v9fs_qid_iget(sb, &st->qid, st, new);
 560	p9stat_free(st);
 561	kfree(st);
 562	return inode;
 563}
 564
 565/**
 566 * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
 567 * plan 9 AT flag.
 568 * @flags: flags to convert
 569 */
 570static int v9fs_at_to_dotl_flags(int flags)
 571{
 572	int rflags = 0;
 573	if (flags & AT_REMOVEDIR)
 574		rflags |= P9_DOTL_AT_REMOVEDIR;
 575	return rflags;
 576}
 577
 578/**
 579 * v9fs_remove - helper function to remove files and directories
 580 * @dir: directory inode that is being deleted
 581 * @dentry:  dentry that is being deleted
 582 * @flags: removing a directory
 583 *
 584 */
 585
 586static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
 587{
 588	struct inode *inode;
 589	int retval = -EOPNOTSUPP;
 590	struct p9_fid *v9fid, *dfid;
 591	struct v9fs_session_info *v9ses;
 592
 593	p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
 594		 dir, dentry, flags);
 595
 596	v9ses = v9fs_inode2v9ses(dir);
 597	inode = d_inode(dentry);
 598	dfid = v9fs_parent_fid(dentry);
 599	if (IS_ERR(dfid)) {
 600		retval = PTR_ERR(dfid);
 601		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
 602		return retval;
 603	}
 604	if (v9fs_proto_dotl(v9ses))
 605		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
 606					    v9fs_at_to_dotl_flags(flags));
 607	if (retval == -EOPNOTSUPP) {
 608		/* Try the one based on path */
 609		v9fid = v9fs_fid_clone(dentry);
 610		if (IS_ERR(v9fid))
 611			return PTR_ERR(v9fid);
 612		retval = p9_client_remove(v9fid);
 613	}
 614	if (!retval) {
 615		/*
 616		 * directories on unlink should have zero
 617		 * link count
 618		 */
 619		if (flags & AT_REMOVEDIR) {
 620			clear_nlink(inode);
 621			drop_nlink(dir);
 622		} else
 623			drop_nlink(inode);
 624
 625		v9fs_invalidate_inode_attr(inode);
 626		v9fs_invalidate_inode_attr(dir);
 627	}
 628	return retval;
 629}
 630
 631/**
 632 * v9fs_create - Create a file
 633 * @v9ses: session information
 634 * @dir: directory that dentry is being created in
 635 * @dentry:  dentry that is being created
 636 * @extension: 9p2000.u extension string to support devices, etc.
 637 * @perm: create permissions
 638 * @mode: open mode
 639 *
 640 */
 641static struct p9_fid *
 642v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 643		struct dentry *dentry, char *extension, u32 perm, u8 mode)
 644{
 645	int err;
 646	char *name;
 647	struct p9_fid *dfid, *ofid, *fid;
 648	struct inode *inode;
 649
 650	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 651
 652	err = 0;
 653	ofid = NULL;
 654	fid = NULL;
 655	name = (char *) dentry->d_name.name;
 656	dfid = v9fs_parent_fid(dentry);
 657	if (IS_ERR(dfid)) {
 658		err = PTR_ERR(dfid);
 659		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 660		return ERR_PTR(err);
 661	}
 662
 663	/* clone a fid to use for creation */
 664	ofid = clone_fid(dfid);
 665	if (IS_ERR(ofid)) {
 666		err = PTR_ERR(ofid);
 667		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 668		return ERR_PTR(err);
 669	}
 670
 671	err = p9_client_fcreate(ofid, name, perm, mode, extension);
 672	if (err < 0) {
 673		p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 674		goto error;
 675	}
 676
 677	if (!(perm & P9_DMLINK)) {
 678		/* now walk from the parent so we can get unopened fid */
 679		fid = p9_client_walk(dfid, 1, &name, 1);
 680		if (IS_ERR(fid)) {
 681			err = PTR_ERR(fid);
 682			p9_debug(P9_DEBUG_VFS,
 683				   "p9_client_walk failed %d\n", err);
 684			fid = NULL;
 685			goto error;
 686		}
 687		/*
 688		 * instantiate inode and assign the unopened fid to the dentry
 689		 */
 690		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 691		if (IS_ERR(inode)) {
 692			err = PTR_ERR(inode);
 693			p9_debug(P9_DEBUG_VFS,
 694				   "inode creation failed %d\n", err);
 695			goto error;
 696		}
 697		v9fs_fid_add(dentry, fid);
 698		d_instantiate(dentry, inode);
 699	}
 700	return ofid;
 701error:
 702	if (ofid)
 703		p9_client_clunk(ofid);
 704
 705	if (fid)
 706		p9_client_clunk(fid);
 707
 708	return ERR_PTR(err);
 709}
 710
 711/**
 712 * v9fs_vfs_create - VFS hook to create a regular file
 713 *
 714 * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
 715 * for mknod(2).
 716 *
 717 * @dir: directory inode that is being created
 718 * @dentry:  dentry that is being deleted
 719 * @mode: create permissions
 720 *
 721 */
 722
 723static int
 724v9fs_vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 725		bool excl)
 726{
 727	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
 728	u32 perm = unixmode2p9mode(v9ses, mode);
 729	struct p9_fid *fid;
 730
 731	/* P9_OEXCL? */
 732	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
 733	if (IS_ERR(fid))
 734		return PTR_ERR(fid);
 735
 736	v9fs_invalidate_inode_attr(dir);
 737	p9_client_clunk(fid);
 738
 739	return 0;
 740}
 741
 742/**
 743 * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 744 * @dir:  inode that is being unlinked
 745 * @dentry: dentry that is being unlinked
 746 * @mode: mode for new directory
 747 *
 748 */
 749
 750static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 751{
 752	int err;
 753	u32 perm;
 754	struct p9_fid *fid;
 755	struct v9fs_session_info *v9ses;
 756
 757	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 758	err = 0;
 759	v9ses = v9fs_inode2v9ses(dir);
 760	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 761	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 762	if (IS_ERR(fid)) {
 763		err = PTR_ERR(fid);
 764		fid = NULL;
 765	} else {
 766		inc_nlink(dir);
 767		v9fs_invalidate_inode_attr(dir);
 768	}
 769
 770	if (fid)
 771		p9_client_clunk(fid);
 772
 773	return err;
 774}
 775
 776/**
 777 * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 778 * @dir:  inode that is being walked from
 779 * @dentry: dentry that is being walked to?
 780 * @flags: lookup flags (unused)
 781 *
 782 */
 783
 784struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 785				      unsigned int flags)
 786{
 787	struct dentry *res;
 788	struct v9fs_session_info *v9ses;
 789	struct p9_fid *dfid, *fid;
 790	struct inode *inode;
 791	char *name;
 792
 793	p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
 794		 dir, dentry, dentry, flags);
 795
 796	if (dentry->d_name.len > NAME_MAX)
 797		return ERR_PTR(-ENAMETOOLONG);
 798
 799	v9ses = v9fs_inode2v9ses(dir);
 800	/* We can walk d_parent because we hold the dir->i_mutex */
 801	dfid = v9fs_parent_fid(dentry);
 802	if (IS_ERR(dfid))
 803		return ERR_CAST(dfid);
 804
 805	name = (char *) dentry->d_name.name;
 806	fid = p9_client_walk(dfid, 1, &name, 1);
 807	if (IS_ERR(fid)) {
 808		if (fid == ERR_PTR(-ENOENT)) {
 809			d_add(dentry, NULL);
 810			return NULL;
 811		}
 812		return ERR_CAST(fid);
 813	}
 814	/*
 815	 * Make sure we don't use a wrong inode due to parallel
 816	 * unlink. For cached mode create calls request for new
 817	 * inode. But with cache disabled, lookup should do this.
 818	 */
 819	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 820		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 821	else
 822		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 823	if (IS_ERR(inode)) {
 824		p9_client_clunk(fid);
 825		return ERR_CAST(inode);
 826	}
 827	/*
 828	 * If we had a rename on the server and a parallel lookup
 829	 * for the new name, then make sure we instantiate with
 830	 * the new name. ie look up for a/b, while on server somebody
 831	 * moved b under k and client parallely did a lookup for
 832	 * k/b.
 833	 */
 834	res = d_splice_alias(inode, dentry);
 835	if (!res)
 836		v9fs_fid_add(dentry, fid);
 837	else if (!IS_ERR(res))
 838		v9fs_fid_add(res, fid);
 839	else
 840		p9_client_clunk(fid);
 841	return res;
 842}
 843
 844static int
 845v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 846		     struct file *file, unsigned flags, umode_t mode,
 847		     int *opened)
 848{
 849	int err;
 850	u32 perm;
 851	struct v9fs_inode *v9inode;
 852	struct v9fs_session_info *v9ses;
 853	struct p9_fid *fid, *inode_fid;
 854	struct dentry *res = NULL;
 855
 856	if (d_in_lookup(dentry)) {
 857		res = v9fs_vfs_lookup(dir, dentry, 0);
 858		if (IS_ERR(res))
 859			return PTR_ERR(res);
 860
 861		if (res)
 862			dentry = res;
 863	}
 864
 865	/* Only creates */
 866	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
 867		return finish_no_open(file, res);
 868
 869	err = 0;
 870
 871	v9ses = v9fs_inode2v9ses(dir);
 872	perm = unixmode2p9mode(v9ses, mode);
 873	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 874				v9fs_uflags2omode(flags,
 875						v9fs_proto_dotu(v9ses)));
 876	if (IS_ERR(fid)) {
 877		err = PTR_ERR(fid);
 878		fid = NULL;
 879		goto error;
 880	}
 881
 882	v9fs_invalidate_inode_attr(dir);
 883	v9inode = V9FS_I(d_inode(dentry));
 884	mutex_lock(&v9inode->v_mutex);
 885	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
 886	    !v9inode->writeback_fid &&
 887	    ((flags & O_ACCMODE) != O_RDONLY)) {
 888		/*
 889		 * clone a fid and add it to writeback_fid
 890		 * we do it during open time instead of
 891		 * page dirty time via write_begin/page_mkwrite
 892		 * because we want write after unlink usecase
 893		 * to work.
 894		 */
 895		inode_fid = v9fs_writeback_fid(dentry);
 896		if (IS_ERR(inode_fid)) {
 897			err = PTR_ERR(inode_fid);
 898			mutex_unlock(&v9inode->v_mutex);
 899			goto error;
 900		}
 901		v9inode->writeback_fid = (void *) inode_fid;
 902	}
 903	mutex_unlock(&v9inode->v_mutex);
 904	err = finish_open(file, dentry, generic_file_open, opened);
 905	if (err)
 906		goto error;
 907
 908	file->private_data = fid;
 909	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 910		v9fs_cache_inode_set_cookie(d_inode(dentry), file);
 911
 912	*opened |= FILE_CREATED;
 913out:
 914	dput(res);
 915	return err;
 916
 917error:
 918	if (fid)
 919		p9_client_clunk(fid);
 920	goto out;
 921}
 922
 923/**
 924 * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 925 * @i:  inode that is being unlinked
 926 * @d: dentry that is being unlinked
 927 *
 928 */
 929
 930int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 931{
 932	return v9fs_remove(i, d, 0);
 933}
 934
 935/**
 936 * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 937 * @i:  inode that is being unlinked
 938 * @d: dentry that is being unlinked
 939 *
 940 */
 941
 942int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 943{
 944	return v9fs_remove(i, d, AT_REMOVEDIR);
 945}
 946
 947/**
 948 * v9fs_vfs_rename - VFS hook to rename an inode
 949 * @old_dir:  old dir inode
 950 * @old_dentry: old dentry
 951 * @new_dir: new dir inode
 952 * @new_dentry: new dentry
 953 *
 954 */
 955
 956int
 957v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 958		struct inode *new_dir, struct dentry *new_dentry,
 959		unsigned int flags)
 960{
 961	int retval;
 962	struct inode *old_inode;
 963	struct inode *new_inode;
 964	struct v9fs_session_info *v9ses;
 965	struct p9_fid *oldfid;
 966	struct p9_fid *olddirfid;
 967	struct p9_fid *newdirfid;
 968	struct p9_wstat wstat;
 969
 970	if (flags)
 971		return -EINVAL;
 972
 973	p9_debug(P9_DEBUG_VFS, "\n");
 974	retval = 0;
 975	old_inode = d_inode(old_dentry);
 976	new_inode = d_inode(new_dentry);
 977	v9ses = v9fs_inode2v9ses(old_inode);
 978	oldfid = v9fs_fid_lookup(old_dentry);
 979	if (IS_ERR(oldfid))
 980		return PTR_ERR(oldfid);
 981
 982	olddirfid = clone_fid(v9fs_parent_fid(old_dentry));
 983	if (IS_ERR(olddirfid)) {
 984		retval = PTR_ERR(olddirfid);
 985		goto done;
 986	}
 987
 988	newdirfid = clone_fid(v9fs_parent_fid(new_dentry));
 989	if (IS_ERR(newdirfid)) {
 990		retval = PTR_ERR(newdirfid);
 991		goto clunk_olddir;
 992	}
 993
 994	down_write(&v9ses->rename_sem);
 995	if (v9fs_proto_dotl(v9ses)) {
 996		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
 997					    newdirfid, new_dentry->d_name.name);
 998		if (retval == -EOPNOTSUPP)
 999			retval = p9_client_rename(oldfid, newdirfid,
1000						  new_dentry->d_name.name);
1001		if (retval != -EOPNOTSUPP)
1002			goto clunk_newdir;
1003	}
1004	if (old_dentry->d_parent != new_dentry->d_parent) {
1005		/*
1006		 * 9P .u can only handle file rename in the same directory
1007		 */
1008
1009		p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
1010		retval = -EXDEV;
1011		goto clunk_newdir;
1012	}
1013	v9fs_blank_wstat(&wstat);
1014	wstat.muid = v9ses->uname;
1015	wstat.name = (char *) new_dentry->d_name.name;
1016	retval = p9_client_wstat(oldfid, &wstat);
1017
1018clunk_newdir:
1019	if (!retval) {
1020		if (new_inode) {
1021			if (S_ISDIR(new_inode->i_mode))
1022				clear_nlink(new_inode);
1023			else
1024				drop_nlink(new_inode);
1025		}
1026		if (S_ISDIR(old_inode->i_mode)) {
1027			if (!new_inode)
1028				inc_nlink(new_dir);
1029			drop_nlink(old_dir);
1030		}
1031		v9fs_invalidate_inode_attr(old_inode);
1032		v9fs_invalidate_inode_attr(old_dir);
1033		v9fs_invalidate_inode_attr(new_dir);
1034
1035		/* successful rename */
1036		d_move(old_dentry, new_dentry);
1037	}
1038	up_write(&v9ses->rename_sem);
1039	p9_client_clunk(newdirfid);
1040
1041clunk_olddir:
1042	p9_client_clunk(olddirfid);
1043
1044done:
1045	return retval;
1046}
1047
1048/**
1049 * v9fs_vfs_getattr - retrieve file metadata
1050 * @mnt: mount information
1051 * @dentry: file to get attributes on
1052 * @stat: metadata structure to populate
1053 *
1054 */
1055
1056static int
1057v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1058		 struct kstat *stat)
1059{
1060	struct v9fs_session_info *v9ses;
1061	struct p9_fid *fid;
1062	struct p9_wstat *st;
1063
1064	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1065	v9ses = v9fs_dentry2v9ses(dentry);
1066	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
1067		generic_fillattr(d_inode(dentry), stat);
1068		return 0;
1069	}
1070	fid = v9fs_fid_lookup(dentry);
1071	if (IS_ERR(fid))
1072		return PTR_ERR(fid);
1073
1074	st = p9_client_stat(fid);
1075	if (IS_ERR(st))
1076		return PTR_ERR(st);
1077
1078	v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb);
1079	generic_fillattr(d_inode(dentry), stat);
1080
1081	p9stat_free(st);
1082	kfree(st);
1083	return 0;
1084}
1085
1086/**
1087 * v9fs_vfs_setattr - set file metadata
1088 * @dentry: file whose metadata to set
1089 * @iattr: metadata assignment structure
1090 *
1091 */
1092
1093static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
1094{
1095	int retval;
1096	struct v9fs_session_info *v9ses;
1097	struct p9_fid *fid;
1098	struct p9_wstat wstat;
1099
1100	p9_debug(P9_DEBUG_VFS, "\n");
1101	retval = setattr_prepare(dentry, iattr);
1102	if (retval)
1103		return retval;
1104
1105	retval = -EPERM;
1106	v9ses = v9fs_dentry2v9ses(dentry);
1107	fid = v9fs_fid_lookup(dentry);
1108	if(IS_ERR(fid))
1109		return PTR_ERR(fid);
1110
1111	v9fs_blank_wstat(&wstat);
1112	if (iattr->ia_valid & ATTR_MODE)
1113		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1114
1115	if (iattr->ia_valid & ATTR_MTIME)
1116		wstat.mtime = iattr->ia_mtime.tv_sec;
1117
1118	if (iattr->ia_valid & ATTR_ATIME)
1119		wstat.atime = iattr->ia_atime.tv_sec;
1120
1121	if (iattr->ia_valid & ATTR_SIZE)
1122		wstat.length = iattr->ia_size;
1123
1124	if (v9fs_proto_dotu(v9ses)) {
1125		if (iattr->ia_valid & ATTR_UID)
1126			wstat.n_uid = iattr->ia_uid;
1127
1128		if (iattr->ia_valid & ATTR_GID)
1129			wstat.n_gid = iattr->ia_gid;
1130	}
1131
1132	/* Write all dirty data */
1133	if (d_is_reg(dentry))
1134		filemap_write_and_wait(d_inode(dentry)->i_mapping);
1135
1136	retval = p9_client_wstat(fid, &wstat);
1137	if (retval < 0)
1138		return retval;
1139
1140	if ((iattr->ia_valid & ATTR_SIZE) &&
1141	    iattr->ia_size != i_size_read(d_inode(dentry)))
1142		truncate_setsize(d_inode(dentry), iattr->ia_size);
1143
1144	v9fs_invalidate_inode_attr(d_inode(dentry));
1145
1146	setattr_copy(d_inode(dentry), iattr);
1147	mark_inode_dirty(d_inode(dentry));
1148	return 0;
1149}
1150
1151/**
1152 * v9fs_stat2inode - populate an inode structure with mistat info
1153 * @stat: Plan 9 metadata (mistat) structure
1154 * @inode: inode to populate
1155 * @sb: superblock of filesystem
1156 *
1157 */
1158
1159void
1160v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1161	struct super_block *sb)
1162{
1163	umode_t mode;
1164	char ext[32];
1165	char tag_name[14];
1166	unsigned int i_nlink;
1167	struct v9fs_session_info *v9ses = sb->s_fs_info;
1168	struct v9fs_inode *v9inode = V9FS_I(inode);
1169
1170	set_nlink(inode, 1);
1171
1172	inode->i_atime.tv_sec = stat->atime;
1173	inode->i_mtime.tv_sec = stat->mtime;
1174	inode->i_ctime.tv_sec = stat->mtime;
1175
1176	inode->i_uid = v9ses->dfltuid;
1177	inode->i_gid = v9ses->dfltgid;
1178
1179	if (v9fs_proto_dotu(v9ses)) {
1180		inode->i_uid = stat->n_uid;
1181		inode->i_gid = stat->n_gid;
1182	}
1183	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1184		if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
1185			/*
1186			 * Hadlink support got added later to
1187			 * to the .u extension. So there can be
1188			 * server out there that doesn't support
1189			 * this even with .u extension. So check
1190			 * for non NULL stat->extension
1191			 */
1192			strlcpy(ext, stat->extension, sizeof(ext));
1193			/* HARDLINKCOUNT %u */
1194			sscanf(ext, "%13s %u", tag_name, &i_nlink);
1195			if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
1196				set_nlink(inode, i_nlink);
1197		}
1198	}
1199	mode = p9mode2perm(v9ses, stat);
1200	mode |= inode->i_mode & ~S_IALLUGO;
1201	inode->i_mode = mode;
1202	i_size_write(inode, stat->length);
1203
1204	/* not real number of blocks, but 512 byte ones ... */
1205	inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
1206	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1207}
1208
1209/**
1210 * v9fs_qid2ino - convert qid into inode number
1211 * @qid: qid to hash
1212 *
1213 * BUG: potential for inode number collisions?
1214 */
1215
1216ino_t v9fs_qid2ino(struct p9_qid *qid)
1217{
1218	u64 path = qid->path + 2;
1219	ino_t i = 0;
1220
1221	if (sizeof(ino_t) == sizeof(path))
1222		memcpy(&i, &path, sizeof(ino_t));
1223	else
1224		i = (ino_t) (path ^ (path >> 32));
1225
1226	return i;
1227}
1228
1229/**
1230 * v9fs_vfs_get_link - follow a symlink path
1231 * @dentry: dentry for symlink
1232 * @inode: inode for symlink
1233 * @done: delayed call for when we are done with the return value
1234 */
1235
1236static const char *v9fs_vfs_get_link(struct dentry *dentry,
1237				     struct inode *inode,
1238				     struct delayed_call *done)
1239{
1240	struct v9fs_session_info *v9ses;
1241	struct p9_fid *fid;
1242	struct p9_wstat *st;
1243	char *res;
1244
1245	if (!dentry)
1246		return ERR_PTR(-ECHILD);
1247
1248	v9ses = v9fs_dentry2v9ses(dentry);
1249	fid = v9fs_fid_lookup(dentry);
1250	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1251
1252	if (IS_ERR(fid))
1253		return ERR_CAST(fid);
1254
1255	if (!v9fs_proto_dotu(v9ses))
1256		return ERR_PTR(-EBADF);
1257
1258	st = p9_client_stat(fid);
1259	if (IS_ERR(st))
1260		return ERR_CAST(st);
1261
1262	if (!(st->mode & P9_DMSYMLINK)) {
1263		p9stat_free(st);
1264		kfree(st);
1265		return ERR_PTR(-EINVAL);
1266	}
1267	res = st->extension;
1268	st->extension = NULL;
1269	if (strlen(res) >= PATH_MAX)
1270		res[PATH_MAX - 1] = '\0';
1271
1272	p9stat_free(st);
1273	kfree(st);
1274	set_delayed_call(done, kfree_link, res);
1275	return res;
1276}
1277
1278/**
1279 * v9fs_vfs_mkspecial - create a special file
1280 * @dir: inode to create special file in
1281 * @dentry: dentry to create
1282 * @perm: mode to create special file
1283 * @extension: 9p2000.u format extension string representing special file
1284 *
1285 */
1286
1287static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1288	u32 perm, const char *extension)
1289{
1290	struct p9_fid *fid;
1291	struct v9fs_session_info *v9ses;
1292
1293	v9ses = v9fs_inode2v9ses(dir);
1294	if (!v9fs_proto_dotu(v9ses)) {
1295		p9_debug(P9_DEBUG_ERROR, "not extended\n");
1296		return -EPERM;
1297	}
1298
1299	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1300								P9_OREAD);
1301	if (IS_ERR(fid))
1302		return PTR_ERR(fid);
1303
1304	v9fs_invalidate_inode_attr(dir);
1305	p9_client_clunk(fid);
1306	return 0;
1307}
1308
1309/**
1310 * v9fs_vfs_symlink - helper function to create symlinks
1311 * @dir: directory inode containing symlink
1312 * @dentry: dentry for symlink
1313 * @symname: symlink data
1314 *
1315 * See Also: 9P2000.u RFC for more information
1316 *
1317 */
1318
1319static int
1320v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1321{
1322	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1323		 dir->i_ino, dentry, symname);
1324
1325	return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1326}
1327
1328#define U32_MAX_DIGITS 10
1329
1330/**
1331 * v9fs_vfs_link - create a hardlink
1332 * @old_dentry: dentry for file to link to
1333 * @dir: inode destination for new link
1334 * @dentry: dentry for link
1335 *
1336 */
1337
1338static int
1339v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1340	      struct dentry *dentry)
1341{
1342	int retval;
1343	char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1344	struct p9_fid *oldfid;
1345
1346	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1347		 dir->i_ino, dentry, old_dentry);
1348
1349	oldfid = v9fs_fid_clone(old_dentry);
1350	if (IS_ERR(oldfid))
1351		return PTR_ERR(oldfid);
1352
1353	sprintf(name, "%d\n", oldfid->fid);
1354	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1355	if (!retval) {
1356		v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1357		v9fs_invalidate_inode_attr(dir);
1358	}
1359	p9_client_clunk(oldfid);
1360	return retval;
1361}
1362
1363/**
1364 * v9fs_vfs_mknod - create a special file
1365 * @dir: inode destination for new link
1366 * @dentry: dentry for file
1367 * @mode: mode for creation
1368 * @rdev: device associated with special file
1369 *
1370 */
1371
1372static int
1373v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
1374{
1375	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1376	int retval;
1377	char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1378	u32 perm;
1379
1380	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %hx MAJOR: %u MINOR: %u\n",
1381		 dir->i_ino, dentry, mode,
1382		 MAJOR(rdev), MINOR(rdev));
1383
1384	/* build extension */
1385	if (S_ISBLK(mode))
1386		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1387	else if (S_ISCHR(mode))
1388		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1389	else
1390		*name = 0;
1391
1392	perm = unixmode2p9mode(v9ses, mode);
1393	retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1394
1395	return retval;
1396}
1397
1398int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1399{
1400	int umode;
1401	dev_t rdev;
1402	loff_t i_size;
1403	struct p9_wstat *st;
1404	struct v9fs_session_info *v9ses;
1405
1406	v9ses = v9fs_inode2v9ses(inode);
1407	st = p9_client_stat(fid);
1408	if (IS_ERR(st))
1409		return PTR_ERR(st);
1410	/*
1411	 * Don't update inode if the file type is different
1412	 */
1413	umode = p9mode2unixmode(v9ses, st, &rdev);
1414	if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
1415		goto out;
1416
1417	spin_lock(&inode->i_lock);
1418	/*
1419	 * We don't want to refresh inode->i_size,
1420	 * because we may have cached data
1421	 */
1422	i_size = inode->i_size;
1423	v9fs_stat2inode(st, inode, inode->i_sb);
1424	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
1425		inode->i_size = i_size;
1426	spin_unlock(&inode->i_lock);
1427out:
1428	p9stat_free(st);
1429	kfree(st);
1430	return 0;
1431}
1432
1433static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1434	.create = v9fs_vfs_create,
1435	.lookup = v9fs_vfs_lookup,
1436	.atomic_open = v9fs_vfs_atomic_open,
1437	.symlink = v9fs_vfs_symlink,
1438	.link = v9fs_vfs_link,
1439	.unlink = v9fs_vfs_unlink,
1440	.mkdir = v9fs_vfs_mkdir,
1441	.rmdir = v9fs_vfs_rmdir,
1442	.mknod = v9fs_vfs_mknod,
1443	.rename = v9fs_vfs_rename,
1444	.getattr = v9fs_vfs_getattr,
1445	.setattr = v9fs_vfs_setattr,
1446};
1447
1448static const struct inode_operations v9fs_dir_inode_operations = {
1449	.create = v9fs_vfs_create,
1450	.lookup = v9fs_vfs_lookup,
1451	.atomic_open = v9fs_vfs_atomic_open,
1452	.unlink = v9fs_vfs_unlink,
1453	.mkdir = v9fs_vfs_mkdir,
1454	.rmdir = v9fs_vfs_rmdir,
1455	.mknod = v9fs_vfs_mknod,
1456	.rename = v9fs_vfs_rename,
1457	.getattr = v9fs_vfs_getattr,
1458	.setattr = v9fs_vfs_setattr,
1459};
1460
1461static const struct inode_operations v9fs_file_inode_operations = {
1462	.getattr = v9fs_vfs_getattr,
1463	.setattr = v9fs_vfs_setattr,
1464};
1465
1466static const struct inode_operations v9fs_symlink_inode_operations = {
1467	.get_link = v9fs_vfs_get_link,
1468	.getattr = v9fs_vfs_getattr,
1469	.setattr = v9fs_vfs_setattr,
1470};
1471