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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
v5.14.15
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/fs/9p/vfs_inode.c
   4 *
   5 * This file contains vfs inode ops for the 9P2000 protocol.
   6 *
   7 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   8 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   9 */
  10
  11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13#include <linux/module.h>
  14#include <linux/errno.h>
  15#include <linux/fs.h>
  16#include <linux/file.h>
  17#include <linux/pagemap.h>
  18#include <linux/stat.h>
  19#include <linux/string.h>
  20#include <linux/inet.h>
  21#include <linux/namei.h>
  22#include <linux/idr.h>
  23#include <linux/sched.h>
  24#include <linux/slab.h>
  25#include <linux/xattr.h>
  26#include <linux/posix_acl.h>
  27#include <net/9p/9p.h>
  28#include <net/9p/client.h>
  29
  30#include "v9fs.h"
  31#include "v9fs_vfs.h"
  32#include "fid.h"
  33#include "cache.h"
  34#include "xattr.h"
  35#include "acl.h"
  36
  37static const struct inode_operations v9fs_dir_inode_operations;
  38static const struct inode_operations v9fs_dir_inode_operations_dotu;
  39static const struct inode_operations v9fs_file_inode_operations;
  40static const struct inode_operations v9fs_symlink_inode_operations;
  41
  42/**
  43 * unixmode2p9mode - convert unix mode bits to plan 9
  44 * @v9ses: v9fs session information
  45 * @mode: mode to convert
  46 *
  47 */
  48
  49static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
  50{
  51	int res;
 
  52	res = mode & 0777;
  53	if (S_ISDIR(mode))
  54		res |= P9_DMDIR;
  55	if (v9fs_proto_dotu(v9ses)) {
  56		if (v9ses->nodev == 0) {
  57			if (S_ISSOCK(mode))
  58				res |= P9_DMSOCKET;
  59			if (S_ISFIFO(mode))
  60				res |= P9_DMNAMEDPIPE;
  61			if (S_ISBLK(mode))
  62				res |= P9_DMDEVICE;
  63			if (S_ISCHR(mode))
  64				res |= P9_DMDEVICE;
  65		}
  66
  67		if ((mode & S_ISUID) == S_ISUID)
  68			res |= P9_DMSETUID;
  69		if ((mode & S_ISGID) == S_ISGID)
  70			res |= P9_DMSETGID;
  71		if ((mode & S_ISVTX) == S_ISVTX)
  72			res |= P9_DMSETVTX;
  73	}
  74	return res;
  75}
  76
  77/**
  78 * p9mode2perm- convert plan9 mode bits to unix permission bits
  79 * @v9ses: v9fs session information
  80 * @stat: p9_wstat from which mode need to be derived
  81 *
  82 */
  83static int p9mode2perm(struct v9fs_session_info *v9ses,
  84		       struct p9_wstat *stat)
  85{
  86	int res;
  87	int mode = stat->mode;
  88
  89	res = mode & S_IALLUGO;
  90	if (v9fs_proto_dotu(v9ses)) {
  91		if ((mode & P9_DMSETUID) == P9_DMSETUID)
  92			res |= S_ISUID;
  93
  94		if ((mode & P9_DMSETGID) == P9_DMSETGID)
  95			res |= S_ISGID;
  96
  97		if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
  98			res |= S_ISVTX;
  99	}
 100	return res;
 101}
 102
 103/**
 104 * p9mode2unixmode- convert plan9 mode bits to unix mode bits
 105 * @v9ses: v9fs session information
 106 * @stat: p9_wstat from which mode need to be derived
 107 * @rdev: major number, minor number in case of device files.
 108 *
 109 */
 110static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
 111			       struct p9_wstat *stat, dev_t *rdev)
 112{
 113	int res;
 114	u32 mode = stat->mode;
 115
 116	*rdev = 0;
 117	res = p9mode2perm(v9ses, stat);
 118
 119	if ((mode & P9_DMDIR) == P9_DMDIR)
 120		res |= S_IFDIR;
 121	else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
 122		res |= S_IFLNK;
 123	else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
 124		 && (v9ses->nodev == 0))
 125		res |= S_IFSOCK;
 126	else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
 127		 && (v9ses->nodev == 0))
 128		res |= S_IFIFO;
 129	else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 130		 && (v9ses->nodev == 0)) {
 131		char type = 0, ext[32];
 132		int major = -1, minor = -1;
 133
 134		strlcpy(ext, stat->extension, sizeof(ext));
 135		sscanf(ext, "%c %i %i", &type, &major, &minor);
 
 
 
 
 
 136		switch (type) {
 137		case 'c':
 138			res |= S_IFCHR;
 139			break;
 140		case 'b':
 141			res |= S_IFBLK;
 142			break;
 143		default:
 144			p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
 145				 type, stat->extension);
 146		}
 147		*rdev = MKDEV(major, minor);
 148	} else
 149		res |= S_IFREG;
 150
 151	return res;
 152}
 153
 154/**
 155 * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 156 * @uflags: flags to convert
 157 * @extended: if .u extensions are active
 158 */
 159
 160int v9fs_uflags2omode(int uflags, int extended)
 161{
 162	int ret;
 163
 164	ret = 0;
 165	switch (uflags&3) {
 166	default:
 167	case O_RDONLY:
 168		ret = P9_OREAD;
 169		break;
 170
 171	case O_WRONLY:
 172		ret = P9_OWRITE;
 173		break;
 174
 175	case O_RDWR:
 176		ret = P9_ORDWR;
 177		break;
 178	}
 179
 
 
 
 180	if (extended) {
 181		if (uflags & O_EXCL)
 182			ret |= P9_OEXCL;
 183
 184		if (uflags & O_APPEND)
 185			ret |= P9_OAPPEND;
 186	}
 187
 188	return ret;
 189}
 190
 191/**
 192 * v9fs_blank_wstat - helper function to setup a 9P stat structure
 193 * @wstat: structure to initialize
 194 *
 195 */
 196
 197void
 198v9fs_blank_wstat(struct p9_wstat *wstat)
 199{
 200	wstat->type = ~0;
 201	wstat->dev = ~0;
 202	wstat->qid.type = ~0;
 203	wstat->qid.version = ~0;
 204	*((long long *)&wstat->qid.path) = ~0;
 205	wstat->mode = ~0;
 206	wstat->atime = ~0;
 207	wstat->mtime = ~0;
 208	wstat->length = ~0;
 209	wstat->name = NULL;
 210	wstat->uid = NULL;
 211	wstat->gid = NULL;
 212	wstat->muid = NULL;
 213	wstat->n_uid = INVALID_UID;
 214	wstat->n_gid = INVALID_GID;
 215	wstat->n_muid = INVALID_UID;
 216	wstat->extension = NULL;
 217}
 218
 219/**
 220 * v9fs_alloc_inode - helper function to allocate an inode
 221 *
 222 */
 223struct inode *v9fs_alloc_inode(struct super_block *sb)
 224{
 225	struct v9fs_inode *v9inode;
 226	v9inode = kmem_cache_alloc(v9fs_inode_cache, GFP_KERNEL);
 
 227	if (!v9inode)
 228		return NULL;
 229#ifdef CONFIG_9P_FSCACHE
 230	v9inode->fscache = NULL;
 231	mutex_init(&v9inode->fscache_lock);
 232#endif
 233	v9inode->writeback_fid = NULL;
 234	v9inode->cache_validity = 0;
 235	mutex_init(&v9inode->v_mutex);
 236	return &v9inode->vfs_inode;
 237}
 238
 239/**
 240 * v9fs_free_inode - destroy an inode
 241 *
 242 */
 243
 244void v9fs_free_inode(struct inode *inode)
 245{
 246	kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
 247}
 248
 
 
 
 
 
 
 
 
 
 249int v9fs_init_inode(struct v9fs_session_info *v9ses,
 250		    struct inode *inode, umode_t mode, dev_t rdev)
 251{
 252	int err = 0;
 253
 254	inode_init_owner(&init_user_ns,inode,  NULL, mode);
 255	inode->i_blocks = 0;
 256	inode->i_rdev = rdev;
 257	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 258	inode->i_mapping->a_ops = &v9fs_addr_operations;
 259	inode->i_private = NULL;
 260
 261	switch (mode & S_IFMT) {
 262	case S_IFIFO:
 263	case S_IFBLK:
 264	case S_IFCHR:
 265	case S_IFSOCK:
 266		if (v9fs_proto_dotl(v9ses)) {
 267			inode->i_op = &v9fs_file_inode_operations_dotl;
 268		} else if (v9fs_proto_dotu(v9ses)) {
 269			inode->i_op = &v9fs_file_inode_operations;
 270		} else {
 271			p9_debug(P9_DEBUG_ERROR,
 272				 "special files without extended mode\n");
 273			err = -EINVAL;
 274			goto error;
 275		}
 276		init_special_inode(inode, inode->i_mode, inode->i_rdev);
 277		break;
 278	case S_IFREG:
 279		if (v9fs_proto_dotl(v9ses)) {
 280			inode->i_op = &v9fs_file_inode_operations_dotl;
 281			if (v9ses->cache == CACHE_LOOSE ||
 282			    v9ses->cache == CACHE_FSCACHE)
 283				inode->i_fop =
 284					&v9fs_cached_file_operations_dotl;
 285			else if (v9ses->cache == CACHE_MMAP)
 286				inode->i_fop = &v9fs_mmap_file_operations_dotl;
 287			else
 288				inode->i_fop = &v9fs_file_operations_dotl;
 289		} else {
 290			inode->i_op = &v9fs_file_inode_operations;
 291			if (v9ses->cache == CACHE_LOOSE ||
 292			    v9ses->cache == CACHE_FSCACHE)
 293				inode->i_fop =
 294					&v9fs_cached_file_operations;
 295			else if (v9ses->cache == CACHE_MMAP)
 296				inode->i_fop = &v9fs_mmap_file_operations;
 297			else
 298				inode->i_fop = &v9fs_file_operations;
 299		}
 300
 301		break;
 302	case S_IFLNK:
 303		if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 304			p9_debug(P9_DEBUG_ERROR,
 305				 "extended modes used with legacy protocol\n");
 306			err = -EINVAL;
 307			goto error;
 308		}
 309
 310		if (v9fs_proto_dotl(v9ses))
 311			inode->i_op = &v9fs_symlink_inode_operations_dotl;
 312		else
 313			inode->i_op = &v9fs_symlink_inode_operations;
 314
 315		break;
 316	case S_IFDIR:
 317		inc_nlink(inode);
 318		if (v9fs_proto_dotl(v9ses))
 319			inode->i_op = &v9fs_dir_inode_operations_dotl;
 320		else if (v9fs_proto_dotu(v9ses))
 321			inode->i_op = &v9fs_dir_inode_operations_dotu;
 322		else
 323			inode->i_op = &v9fs_dir_inode_operations;
 324
 325		if (v9fs_proto_dotl(v9ses))
 326			inode->i_fop = &v9fs_dir_operations_dotl;
 327		else
 328			inode->i_fop = &v9fs_dir_operations;
 329
 330		break;
 331	default:
 332		p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
 333			 mode, mode & S_IFMT);
 334		err = -EINVAL;
 335		goto error;
 336	}
 337error:
 338	return err;
 339
 340}
 341
 342/**
 343 * v9fs_get_inode - helper function to setup an inode
 344 * @sb: superblock
 345 * @mode: mode to setup inode with
 346 *
 347 */
 348
 349struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t rdev)
 350{
 351	int err;
 352	struct inode *inode;
 353	struct v9fs_session_info *v9ses = sb->s_fs_info;
 354
 355	p9_debug(P9_DEBUG_VFS, "super block: %p mode: %ho\n", sb, mode);
 
 
 356
 357	inode = new_inode(sb);
 358	if (!inode) {
 359		pr_warn("%s (%d): Problem allocating inode\n",
 360			__func__, task_pid_nr(current));
 361		return ERR_PTR(-ENOMEM);
 362	}
 363	err = v9fs_init_inode(v9ses, inode, mode, rdev);
 364	if (err) {
 365		iput(inode);
 366		return ERR_PTR(err);
 367	}
 368	return inode;
 369}
 370
 371/**
 372 * v9fs_clear_inode - release an inode
 373 * @inode: inode to release
 374 *
 375 */
 376void v9fs_evict_inode(struct inode *inode)
 377{
 378	struct v9fs_inode *v9inode = V9FS_I(inode);
 379
 380	truncate_inode_pages_final(&inode->i_data);
 381	clear_inode(inode);
 382	filemap_fdatawrite(&inode->i_data);
 383
 384	v9fs_cache_inode_put_cookie(inode);
 385	/* clunk the fid stashed in writeback_fid */
 386	if (v9inode->writeback_fid) {
 387		p9_client_clunk(v9inode->writeback_fid);
 388		v9inode->writeback_fid = NULL;
 389	}
 390}
 391
 392static int v9fs_test_inode(struct inode *inode, void *data)
 393{
 394	int umode;
 395	dev_t rdev;
 396	struct v9fs_inode *v9inode = V9FS_I(inode);
 397	struct p9_wstat *st = (struct p9_wstat *)data;
 398	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 399
 400	umode = p9mode2unixmode(v9ses, st, &rdev);
 401	/* don't match inode of different type */
 402	if (inode_wrong_type(inode, umode))
 403		return 0;
 404
 405	/* compare qid details */
 406	if (memcmp(&v9inode->qid.version,
 407		   &st->qid.version, sizeof(v9inode->qid.version)))
 408		return 0;
 409
 410	if (v9inode->qid.type != st->qid.type)
 411		return 0;
 412
 413	if (v9inode->qid.path != st->qid.path)
 414		return 0;
 415	return 1;
 416}
 417
 418static int v9fs_test_new_inode(struct inode *inode, void *data)
 419{
 420	return 0;
 421}
 422
 423static int v9fs_set_inode(struct inode *inode,  void *data)
 424{
 425	struct v9fs_inode *v9inode = V9FS_I(inode);
 426	struct p9_wstat *st = (struct p9_wstat *)data;
 427
 428	memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
 429	return 0;
 430}
 431
 432static struct inode *v9fs_qid_iget(struct super_block *sb,
 433				   struct p9_qid *qid,
 434				   struct p9_wstat *st,
 435				   int new)
 436{
 437	dev_t rdev;
 438	int retval;
 439	umode_t umode;
 440	unsigned long i_ino;
 441	struct inode *inode;
 442	struct v9fs_session_info *v9ses = sb->s_fs_info;
 443	int (*test)(struct inode *, void *);
 444
 445	if (new)
 446		test = v9fs_test_new_inode;
 447	else
 448		test = v9fs_test_inode;
 449
 450	i_ino = v9fs_qid2ino(qid);
 451	inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
 452	if (!inode)
 453		return ERR_PTR(-ENOMEM);
 454	if (!(inode->i_state & I_NEW))
 455		return inode;
 456	/*
 457	 * initialize the inode with the stat info
 458	 * FIXME!! we may need support for stale inodes
 459	 * later.
 460	 */
 461	inode->i_ino = i_ino;
 462	umode = p9mode2unixmode(v9ses, st, &rdev);
 463	retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 464	if (retval)
 465		goto error;
 466
 467	v9fs_stat2inode(st, inode, sb, 0);
 
 468	v9fs_cache_inode_get_cookie(inode);
 469	unlock_new_inode(inode);
 470	return inode;
 471error:
 472	iget_failed(inode);
 473	return ERR_PTR(retval);
 474
 475}
 476
 477struct inode *
 478v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 479		    struct super_block *sb, int new)
 480{
 481	struct p9_wstat *st;
 482	struct inode *inode = NULL;
 483
 484	st = p9_client_stat(fid);
 485	if (IS_ERR(st))
 486		return ERR_CAST(st);
 487
 488	inode = v9fs_qid_iget(sb, &st->qid, st, new);
 489	p9stat_free(st);
 490	kfree(st);
 491	return inode;
 492}
 493
 494/**
 495 * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
 496 * plan 9 AT flag.
 497 * @flags: flags to convert
 498 */
 499static int v9fs_at_to_dotl_flags(int flags)
 500{
 501	int rflags = 0;
 
 502	if (flags & AT_REMOVEDIR)
 503		rflags |= P9_DOTL_AT_REMOVEDIR;
 
 504	return rflags;
 505}
 506
 507/**
 508 * v9fs_dec_count - helper functon to drop i_nlink.
 509 *
 510 * If a directory had nlink <= 2 (including . and ..), then we should not drop
 511 * the link count, which indicates the underlying exported fs doesn't maintain
 512 * nlink accurately. e.g.
 513 * - overlayfs sets nlink to 1 for merged dir
 514 * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
 515 *   than EXT4_LINK_MAX (65000) links.
 516 *
 517 * @inode: inode whose nlink is being dropped
 518 */
 519static void v9fs_dec_count(struct inode *inode)
 520{
 521	if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
 522		drop_nlink(inode);
 523}
 524
 525/**
 526 * v9fs_remove - helper function to remove files and directories
 527 * @dir: directory inode that is being deleted
 528 * @dentry:  dentry that is being deleted
 529 * @flags: removing a directory
 530 *
 531 */
 532
 533static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
 534{
 535	struct inode *inode;
 536	int retval = -EOPNOTSUPP;
 537	struct p9_fid *v9fid, *dfid;
 538	struct v9fs_session_info *v9ses;
 539
 540	p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
 541		 dir, dentry, flags);
 542
 543	v9ses = v9fs_inode2v9ses(dir);
 544	inode = d_inode(dentry);
 545	dfid = v9fs_parent_fid(dentry);
 546	if (IS_ERR(dfid)) {
 547		retval = PTR_ERR(dfid);
 548		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
 549		return retval;
 550	}
 551	if (v9fs_proto_dotl(v9ses))
 552		retval = p9_client_unlinkat(dfid, dentry->d_name.name,
 553					    v9fs_at_to_dotl_flags(flags));
 554	p9_client_clunk(dfid);
 555	if (retval == -EOPNOTSUPP) {
 556		/* Try the one based on path */
 557		v9fid = v9fs_fid_clone(dentry);
 558		if (IS_ERR(v9fid))
 559			return PTR_ERR(v9fid);
 560		retval = p9_client_remove(v9fid);
 561	}
 562	if (!retval) {
 563		/*
 564		 * directories on unlink should have zero
 565		 * link count
 566		 */
 567		if (flags & AT_REMOVEDIR) {
 568			clear_nlink(inode);
 569			v9fs_dec_count(dir);
 570		} else
 571			v9fs_dec_count(inode);
 572
 573		v9fs_invalidate_inode_attr(inode);
 574		v9fs_invalidate_inode_attr(dir);
 575
 576		/* invalidate all fids associated with dentry */
 577		/* NOTE: This will not include open fids */
 578		dentry->d_op->d_release(dentry);
 579	}
 580	return retval;
 581}
 582
 583/**
 584 * v9fs_create - Create a file
 585 * @v9ses: session information
 586 * @dir: directory that dentry is being created in
 587 * @dentry:  dentry that is being created
 588 * @extension: 9p2000.u extension string to support devices, etc.
 589 * @perm: create permissions
 590 * @mode: open mode
 591 *
 592 */
 593static struct p9_fid *
 594v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 595		struct dentry *dentry, char *extension, u32 perm, u8 mode)
 596{
 597	int err;
 598	const unsigned char *name;
 599	struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
 600	struct inode *inode;
 601
 602	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 603
 604	err = 0;
 605	name = dentry->d_name.name;
 606	dfid = v9fs_parent_fid(dentry);
 607	if (IS_ERR(dfid)) {
 608		err = PTR_ERR(dfid);
 609		p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 610		return ERR_PTR(err);
 611	}
 612
 613	/* clone a fid to use for creation */
 614	ofid = clone_fid(dfid);
 615	if (IS_ERR(ofid)) {
 616		err = PTR_ERR(ofid);
 617		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 618		p9_client_clunk(dfid);
 619		return ERR_PTR(err);
 620	}
 621
 622	err = p9_client_fcreate(ofid, name, perm, mode, extension);
 623	if (err < 0) {
 624		p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 625		p9_client_clunk(dfid);
 626		goto error;
 627	}
 628
 629	if (!(perm & P9_DMLINK)) {
 630		/* now walk from the parent so we can get unopened fid */
 631		fid = p9_client_walk(dfid, 1, &name, 1);
 632		if (IS_ERR(fid)) {
 633			err = PTR_ERR(fid);
 634			p9_debug(P9_DEBUG_VFS,
 635				   "p9_client_walk failed %d\n", err);
 636			fid = NULL;
 637			p9_client_clunk(dfid);
 638			goto error;
 639		}
 640		/*
 641		 * instantiate inode and assign the unopened fid to the dentry
 642		 */
 643		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 644		if (IS_ERR(inode)) {
 645			err = PTR_ERR(inode);
 646			p9_debug(P9_DEBUG_VFS,
 647				   "inode creation failed %d\n", err);
 648			p9_client_clunk(dfid);
 649			goto error;
 650		}
 651		v9fs_fid_add(dentry, fid);
 652		d_instantiate(dentry, inode);
 653	}
 654	p9_client_clunk(dfid);
 655	return ofid;
 656error:
 657	if (ofid)
 658		p9_client_clunk(ofid);
 659
 660	if (fid)
 661		p9_client_clunk(fid);
 662
 663	return ERR_PTR(err);
 664}
 665
 666/**
 667 * v9fs_vfs_create - VFS hook to create a regular file
 
 
 
 
 
 668 *
 669 * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
 670 * for mknod(2).
 671 *
 672 * @dir: directory inode that is being created
 673 * @dentry:  dentry that is being deleted
 674 * @mode: create permissions
 675 *
 676 */
 677
 678static int
 679v9fs_vfs_create(struct user_namespace *mnt_userns, struct inode *dir,
 680		struct dentry *dentry, umode_t mode, bool excl)
 681{
 682	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
 683	u32 perm = unixmode2p9mode(v9ses, mode);
 684	struct p9_fid *fid;
 685
 686	/* P9_OEXCL? */
 687	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
 688	if (IS_ERR(fid))
 689		return PTR_ERR(fid);
 690
 691	v9fs_invalidate_inode_attr(dir);
 692	p9_client_clunk(fid);
 693
 694	return 0;
 695}
 696
 697/**
 698 * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 
 699 * @dir:  inode that is being unlinked
 700 * @dentry: dentry that is being unlinked
 701 * @mode: mode for new directory
 702 *
 703 */
 704
 705static int v9fs_vfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 706			  struct dentry *dentry, umode_t mode)
 707{
 708	int err;
 709	u32 perm;
 710	struct p9_fid *fid;
 711	struct v9fs_session_info *v9ses;
 712
 713	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 714	err = 0;
 715	v9ses = v9fs_inode2v9ses(dir);
 716	perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 717	fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 718	if (IS_ERR(fid)) {
 719		err = PTR_ERR(fid);
 720		fid = NULL;
 721	} else {
 722		inc_nlink(dir);
 723		v9fs_invalidate_inode_attr(dir);
 724	}
 725
 726	if (fid)
 727		p9_client_clunk(fid);
 728
 729	return err;
 730}
 731
 732/**
 733 * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 734 * @dir:  inode that is being walked from
 735 * @dentry: dentry that is being walked to?
 736 * @flags: lookup flags (unused)
 737 *
 738 */
 739
 740struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 741				      unsigned int flags)
 742{
 743	struct dentry *res;
 744	struct v9fs_session_info *v9ses;
 745	struct p9_fid *dfid, *fid;
 746	struct inode *inode;
 747	const unsigned char *name;
 748
 749	p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
 750		 dir, dentry, dentry, flags);
 751
 752	if (dentry->d_name.len > NAME_MAX)
 753		return ERR_PTR(-ENAMETOOLONG);
 754
 755	v9ses = v9fs_inode2v9ses(dir);
 756	/* We can walk d_parent because we hold the dir->i_mutex */
 757	dfid = v9fs_parent_fid(dentry);
 758	if (IS_ERR(dfid))
 759		return ERR_CAST(dfid);
 760
 761	/*
 762	 * Make sure we don't use a wrong inode due to parallel
 763	 * unlink. For cached mode create calls request for new
 764	 * inode. But with cache disabled, lookup should do this.
 765	 */
 766	name = dentry->d_name.name;
 767	fid = p9_client_walk(dfid, 1, &name, 1);
 768	p9_client_clunk(dfid);
 769	if (fid == ERR_PTR(-ENOENT))
 770		inode = NULL;
 771	else if (IS_ERR(fid))
 772		inode = ERR_CAST(fid);
 773	else if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 774		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 775	else
 776		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 777	/*
 778	 * If we had a rename on the server and a parallel lookup
 779	 * for the new name, then make sure we instantiate with
 780	 * the new name. ie look up for a/b, while on server somebody
 781	 * moved b under k and client parallely did a lookup for
 782	 * k/b.
 783	 */
 784	res = d_splice_alias(inode, dentry);
 785	if (!IS_ERR(fid)) {
 786		if (!res)
 787			v9fs_fid_add(dentry, fid);
 788		else if (!IS_ERR(res))
 789			v9fs_fid_add(res, fid);
 790		else
 791			p9_client_clunk(fid);
 792	}
 793	return res;
 794}
 795
 796static int
 797v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 798		     struct file *file, unsigned flags, umode_t mode)
 799{
 800	int err;
 801	u32 perm;
 802	struct v9fs_inode *v9inode;
 803	struct v9fs_session_info *v9ses;
 804	struct p9_fid *fid, *inode_fid;
 805	struct dentry *res = NULL;
 806	struct inode *inode;
 
 807
 808	if (d_in_lookup(dentry)) {
 809		res = v9fs_vfs_lookup(dir, dentry, 0);
 810		if (IS_ERR(res))
 811			return PTR_ERR(res);
 812
 813		if (res)
 814			dentry = res;
 815	}
 816
 817	/* Only creates */
 818	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
 819		return finish_no_open(file, res);
 820
 821	err = 0;
 822
 823	v9ses = v9fs_inode2v9ses(dir);
 824	perm = unixmode2p9mode(v9ses, mode);
 825	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 826				v9fs_uflags2omode(flags,
 827						v9fs_proto_dotu(v9ses)));
 
 
 
 
 
 828	if (IS_ERR(fid)) {
 829		err = PTR_ERR(fid);
 830		fid = NULL;
 831		goto error;
 832	}
 833
 834	v9fs_invalidate_inode_attr(dir);
 835	inode = d_inode(dentry);
 836	v9inode = V9FS_I(inode);
 837	mutex_lock(&v9inode->v_mutex);
 838	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
 839	    !v9inode->writeback_fid &&
 840	    ((flags & O_ACCMODE) != O_RDONLY)) {
 841		/*
 842		 * clone a fid and add it to writeback_fid
 843		 * we do it during open time instead of
 844		 * page dirty time via write_begin/page_mkwrite
 845		 * because we want write after unlink usecase
 846		 * to work.
 847		 */
 848		inode_fid = v9fs_writeback_fid(dentry);
 849		if (IS_ERR(inode_fid)) {
 850			err = PTR_ERR(inode_fid);
 851			mutex_unlock(&v9inode->v_mutex);
 852			goto error;
 853		}
 854		v9inode->writeback_fid = (void *) inode_fid;
 855	}
 856	mutex_unlock(&v9inode->v_mutex);
 857	err = finish_open(file, dentry, generic_file_open);
 858	if (err)
 859		goto error;
 860
 861	file->private_data = fid;
 862	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 863		v9fs_cache_inode_set_cookie(d_inode(dentry), file);
 864	v9fs_open_fid_add(inode, fid);
 
 
 
 
 
 865
 866	file->f_mode |= FMODE_CREATED;
 867out:
 868	dput(res);
 869	return err;
 870
 871error:
 872	if (fid)
 873		p9_client_clunk(fid);
 874	goto out;
 875}
 876
 877/**
 878 * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 879 * @i:  inode that is being unlinked
 880 * @d: dentry that is being unlinked
 881 *
 882 */
 883
 884int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 885{
 886	return v9fs_remove(i, d, 0);
 887}
 888
 889/**
 890 * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 891 * @i:  inode that is being unlinked
 892 * @d: dentry that is being unlinked
 893 *
 894 */
 895
 896int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 897{
 898	return v9fs_remove(i, d, AT_REMOVEDIR);
 899}
 900
 901/**
 902 * v9fs_vfs_rename - VFS hook to rename an inode
 
 903 * @old_dir:  old dir inode
 904 * @old_dentry: old dentry
 905 * @new_dir: new dir inode
 906 * @new_dentry: new dentry
 
 907 *
 908 */
 909
 910int
 911v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 912		struct dentry *old_dentry, struct inode *new_dir,
 913		struct dentry *new_dentry, unsigned int flags)
 914{
 915	int retval;
 916	struct inode *old_inode;
 917	struct inode *new_inode;
 918	struct v9fs_session_info *v9ses;
 919	struct p9_fid *oldfid, *dfid;
 920	struct p9_fid *olddirfid;
 921	struct p9_fid *newdirfid;
 922	struct p9_wstat wstat;
 923
 924	if (flags)
 925		return -EINVAL;
 926
 927	p9_debug(P9_DEBUG_VFS, "\n");
 928	retval = 0;
 929	old_inode = d_inode(old_dentry);
 930	new_inode = d_inode(new_dentry);
 931	v9ses = v9fs_inode2v9ses(old_inode);
 932	oldfid = v9fs_fid_lookup(old_dentry);
 933	if (IS_ERR(oldfid))
 934		return PTR_ERR(oldfid);
 935
 936	dfid = v9fs_parent_fid(old_dentry);
 937	olddirfid = clone_fid(dfid);
 938	if (dfid && !IS_ERR(dfid))
 939		p9_client_clunk(dfid);
 940
 941	if (IS_ERR(olddirfid)) {
 942		retval = PTR_ERR(olddirfid);
 943		goto done;
 944	}
 945
 946	dfid = v9fs_parent_fid(new_dentry);
 947	newdirfid = clone_fid(dfid);
 948	p9_client_clunk(dfid);
 
 949
 950	if (IS_ERR(newdirfid)) {
 951		retval = PTR_ERR(newdirfid);
 952		goto clunk_olddir;
 953	}
 954
 955	down_write(&v9ses->rename_sem);
 956	if (v9fs_proto_dotl(v9ses)) {
 957		retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
 958					    newdirfid, new_dentry->d_name.name);
 959		if (retval == -EOPNOTSUPP)
 960			retval = p9_client_rename(oldfid, newdirfid,
 961						  new_dentry->d_name.name);
 962		if (retval != -EOPNOTSUPP)
 963			goto clunk_newdir;
 964	}
 965	if (old_dentry->d_parent != new_dentry->d_parent) {
 966		/*
 967		 * 9P .u can only handle file rename in the same directory
 968		 */
 969
 970		p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
 971		retval = -EXDEV;
 972		goto clunk_newdir;
 973	}
 974	v9fs_blank_wstat(&wstat);
 975	wstat.muid = v9ses->uname;
 976	wstat.name = new_dentry->d_name.name;
 977	retval = p9_client_wstat(oldfid, &wstat);
 978
 979clunk_newdir:
 980	if (!retval) {
 981		if (new_inode) {
 982			if (S_ISDIR(new_inode->i_mode))
 983				clear_nlink(new_inode);
 984			else
 985				v9fs_dec_count(new_inode);
 986		}
 987		if (S_ISDIR(old_inode->i_mode)) {
 988			if (!new_inode)
 989				inc_nlink(new_dir);
 990			v9fs_dec_count(old_dir);
 991		}
 992		v9fs_invalidate_inode_attr(old_inode);
 993		v9fs_invalidate_inode_attr(old_dir);
 994		v9fs_invalidate_inode_attr(new_dir);
 995
 996		/* successful rename */
 997		d_move(old_dentry, new_dentry);
 998	}
 999	up_write(&v9ses->rename_sem);
1000	p9_client_clunk(newdirfid);
1001
1002clunk_olddir:
1003	p9_client_clunk(olddirfid);
1004
1005done:
1006	p9_client_clunk(oldfid);
1007	return retval;
1008}
1009
1010/**
1011 * v9fs_vfs_getattr - retrieve file metadata
 
1012 * @path: Object to query
1013 * @stat: metadata structure to populate
1014 * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
1015 * @flags: AT_STATX_xxx setting
1016 *
1017 */
1018
1019static int
1020v9fs_vfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
1021		 struct kstat *stat, u32 request_mask, unsigned int flags)
1022{
1023	struct dentry *dentry = path->dentry;
 
1024	struct v9fs_session_info *v9ses;
1025	struct p9_fid *fid;
1026	struct p9_wstat *st;
1027
1028	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1029	v9ses = v9fs_dentry2v9ses(dentry);
1030	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
1031		generic_fillattr(&init_user_ns, d_inode(dentry), stat);
1032		return 0;
 
 
 
 
 
 
 
 
1033	}
1034	fid = v9fs_fid_lookup(dentry);
1035	if (IS_ERR(fid))
1036		return PTR_ERR(fid);
1037
1038	st = p9_client_stat(fid);
1039	p9_client_clunk(fid);
1040	if (IS_ERR(st))
1041		return PTR_ERR(st);
1042
1043	v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
1044	generic_fillattr(&init_user_ns, d_inode(dentry), stat);
1045
1046	p9stat_free(st);
1047	kfree(st);
1048	return 0;
1049}
1050
1051/**
1052 * v9fs_vfs_setattr - set file metadata
 
1053 * @dentry: file whose metadata to set
1054 * @iattr: metadata assignment structure
1055 *
1056 */
1057
1058static int v9fs_vfs_setattr(struct user_namespace *mnt_userns,
1059			    struct dentry *dentry, struct iattr *iattr)
1060{
1061	int retval, use_dentry = 0;
 
1062	struct v9fs_session_info *v9ses;
1063	struct p9_fid *fid = NULL;
1064	struct p9_wstat wstat;
1065
1066	p9_debug(P9_DEBUG_VFS, "\n");
1067	retval = setattr_prepare(&init_user_ns, dentry, iattr);
1068	if (retval)
1069		return retval;
1070
1071	retval = -EPERM;
1072	v9ses = v9fs_dentry2v9ses(dentry);
1073	if (iattr->ia_valid & ATTR_FILE) {
1074		fid = iattr->ia_file->private_data;
1075		WARN_ON(!fid);
1076	}
1077	if (!fid) {
1078		fid = v9fs_fid_lookup(dentry);
1079		use_dentry = 1;
1080	}
1081	if(IS_ERR(fid))
1082		return PTR_ERR(fid);
1083
1084	v9fs_blank_wstat(&wstat);
1085	if (iattr->ia_valid & ATTR_MODE)
1086		wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1087
1088	if (iattr->ia_valid & ATTR_MTIME)
1089		wstat.mtime = iattr->ia_mtime.tv_sec;
1090
1091	if (iattr->ia_valid & ATTR_ATIME)
1092		wstat.atime = iattr->ia_atime.tv_sec;
1093
1094	if (iattr->ia_valid & ATTR_SIZE)
1095		wstat.length = iattr->ia_size;
1096
1097	if (v9fs_proto_dotu(v9ses)) {
1098		if (iattr->ia_valid & ATTR_UID)
1099			wstat.n_uid = iattr->ia_uid;
1100
1101		if (iattr->ia_valid & ATTR_GID)
1102			wstat.n_gid = iattr->ia_gid;
1103	}
1104
1105	/* Write all dirty data */
1106	if (d_is_reg(dentry))
1107		filemap_write_and_wait(d_inode(dentry)->i_mapping);
 
 
 
 
1108
1109	retval = p9_client_wstat(fid, &wstat);
1110
1111	if (use_dentry)
1112		p9_client_clunk(fid);
1113
1114	if (retval < 0)
1115		return retval;
1116
1117	if ((iattr->ia_valid & ATTR_SIZE) &&
1118	    iattr->ia_size != i_size_read(d_inode(dentry)))
1119		truncate_setsize(d_inode(dentry), iattr->ia_size);
 
1120
1121	v9fs_invalidate_inode_attr(d_inode(dentry));
 
 
1122
1123	setattr_copy(&init_user_ns, d_inode(dentry), iattr);
1124	mark_inode_dirty(d_inode(dentry));
 
 
 
 
 
 
 
1125	return 0;
1126}
1127
1128/**
1129 * v9fs_stat2inode - populate an inode structure with mistat info
1130 * @stat: Plan 9 metadata (mistat) structure
1131 * @inode: inode to populate
1132 * @sb: superblock of filesystem
1133 * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1134 *
1135 */
1136
1137void
1138v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1139		 struct super_block *sb, unsigned int flags)
1140{
1141	umode_t mode;
1142	struct v9fs_session_info *v9ses = sb->s_fs_info;
1143	struct v9fs_inode *v9inode = V9FS_I(inode);
1144
1145	set_nlink(inode, 1);
1146
1147	inode->i_atime.tv_sec = stat->atime;
1148	inode->i_mtime.tv_sec = stat->mtime;
1149	inode->i_ctime.tv_sec = stat->mtime;
1150
1151	inode->i_uid = v9ses->dfltuid;
1152	inode->i_gid = v9ses->dfltgid;
1153
1154	if (v9fs_proto_dotu(v9ses)) {
1155		inode->i_uid = stat->n_uid;
1156		inode->i_gid = stat->n_gid;
1157	}
1158	if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1159		if (v9fs_proto_dotu(v9ses)) {
1160			unsigned int i_nlink;
1161			/*
1162			 * Hadlink support got added later to the .u extension.
1163			 * So there can be a server out there that doesn't
1164			 * support this even with .u extension. That would
1165			 * just leave us with stat->extension being an empty
1166			 * string, though.
1167			 */
1168			/* HARDLINKCOUNT %u */
1169			if (sscanf(stat->extension,
1170				   " HARDLINKCOUNT %u", &i_nlink) == 1)
1171				set_nlink(inode, i_nlink);
1172		}
1173	}
1174	mode = p9mode2perm(v9ses, stat);
1175	mode |= inode->i_mode & ~S_IALLUGO;
1176	inode->i_mode = mode;
1177
 
1178	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1179		v9fs_i_size_write(inode, stat->length);
1180	/* not real number of blocks, but 512 byte ones ... */
1181	inode->i_blocks = (stat->length + 512 - 1) >> 9;
1182	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1183}
1184
1185/**
1186 * v9fs_qid2ino - convert qid into inode number
1187 * @qid: qid to hash
1188 *
1189 * BUG: potential for inode number collisions?
1190 */
1191
1192ino_t v9fs_qid2ino(struct p9_qid *qid)
1193{
1194	u64 path = qid->path + 2;
1195	ino_t i = 0;
1196
1197	if (sizeof(ino_t) == sizeof(path))
1198		memcpy(&i, &path, sizeof(ino_t));
1199	else
1200		i = (ino_t) (path ^ (path >> 32));
1201
1202	return i;
1203}
1204
1205/**
1206 * v9fs_vfs_get_link - follow a symlink path
1207 * @dentry: dentry for symlink
1208 * @inode: inode for symlink
1209 * @done: delayed call for when we are done with the return value
1210 */
1211
1212static const char *v9fs_vfs_get_link(struct dentry *dentry,
1213				     struct inode *inode,
1214				     struct delayed_call *done)
1215{
1216	struct v9fs_session_info *v9ses;
1217	struct p9_fid *fid;
1218	struct p9_wstat *st;
1219	char *res;
1220
1221	if (!dentry)
1222		return ERR_PTR(-ECHILD);
1223
1224	v9ses = v9fs_dentry2v9ses(dentry);
 
 
 
 
1225	fid = v9fs_fid_lookup(dentry);
1226	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1227
1228	if (IS_ERR(fid))
1229		return ERR_CAST(fid);
1230
1231	if (!v9fs_proto_dotu(v9ses))
1232		return ERR_PTR(-EBADF);
1233
1234	st = p9_client_stat(fid);
1235	p9_client_clunk(fid);
1236	if (IS_ERR(st))
1237		return ERR_CAST(st);
1238
1239	if (!(st->mode & P9_DMSYMLINK)) {
1240		p9stat_free(st);
1241		kfree(st);
1242		return ERR_PTR(-EINVAL);
1243	}
1244	res = st->extension;
1245	st->extension = NULL;
1246	if (strlen(res) >= PATH_MAX)
1247		res[PATH_MAX - 1] = '\0';
1248
1249	p9stat_free(st);
1250	kfree(st);
1251	set_delayed_call(done, kfree_link, res);
1252	return res;
1253}
1254
1255/**
1256 * v9fs_vfs_mkspecial - create a special file
1257 * @dir: inode to create special file in
1258 * @dentry: dentry to create
1259 * @perm: mode to create special file
1260 * @extension: 9p2000.u format extension string representing special file
1261 *
1262 */
1263
1264static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1265	u32 perm, const char *extension)
1266{
1267	struct p9_fid *fid;
1268	struct v9fs_session_info *v9ses;
1269
1270	v9ses = v9fs_inode2v9ses(dir);
1271	if (!v9fs_proto_dotu(v9ses)) {
1272		p9_debug(P9_DEBUG_ERROR, "not extended\n");
1273		return -EPERM;
1274	}
1275
1276	fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1277								P9_OREAD);
1278	if (IS_ERR(fid))
1279		return PTR_ERR(fid);
1280
1281	v9fs_invalidate_inode_attr(dir);
1282	p9_client_clunk(fid);
1283	return 0;
1284}
1285
1286/**
1287 * v9fs_vfs_symlink - helper function to create symlinks
 
1288 * @dir: directory inode containing symlink
1289 * @dentry: dentry for symlink
1290 * @symname: symlink data
1291 *
1292 * See Also: 9P2000.u RFC for more information
1293 *
1294 */
1295
1296static int
1297v9fs_vfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
1298		 struct dentry *dentry, const char *symname)
1299{
1300	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1301		 dir->i_ino, dentry, symname);
1302
1303	return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1304}
1305
1306#define U32_MAX_DIGITS 10
1307
1308/**
1309 * v9fs_vfs_link - create a hardlink
1310 * @old_dentry: dentry for file to link to
1311 * @dir: inode destination for new link
1312 * @dentry: dentry for link
1313 *
1314 */
1315
1316static int
1317v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1318	      struct dentry *dentry)
1319{
1320	int retval;
1321	char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1322	struct p9_fid *oldfid;
1323
1324	p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1325		 dir->i_ino, dentry, old_dentry);
1326
1327	oldfid = v9fs_fid_clone(old_dentry);
1328	if (IS_ERR(oldfid))
1329		return PTR_ERR(oldfid);
1330
1331	sprintf(name, "%d\n", oldfid->fid);
1332	retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1333	if (!retval) {
1334		v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1335		v9fs_invalidate_inode_attr(dir);
1336	}
1337	p9_client_clunk(oldfid);
1338	return retval;
1339}
1340
1341/**
1342 * v9fs_vfs_mknod - create a special file
 
1343 * @dir: inode destination for new link
1344 * @dentry: dentry for file
1345 * @mode: mode for creation
1346 * @rdev: device associated with special file
1347 *
1348 */
1349
1350static int
1351v9fs_vfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
1352	       struct dentry *dentry, umode_t mode, dev_t rdev)
1353{
1354	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1355	int retval;
1356	char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1357	u32 perm;
1358
1359	p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %hx MAJOR: %u MINOR: %u\n",
1360		 dir->i_ino, dentry, mode,
1361		 MAJOR(rdev), MINOR(rdev));
1362
1363	/* build extension */
1364	if (S_ISBLK(mode))
1365		sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1366	else if (S_ISCHR(mode))
1367		sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1368	else
1369		*name = 0;
1370
1371	perm = unixmode2p9mode(v9ses, mode);
1372	retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1373
1374	return retval;
1375}
1376
1377int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1378{
1379	int umode;
1380	dev_t rdev;
1381	struct p9_wstat *st;
1382	struct v9fs_session_info *v9ses;
1383	unsigned int flags;
1384
1385	v9ses = v9fs_inode2v9ses(inode);
1386	st = p9_client_stat(fid);
1387	if (IS_ERR(st))
1388		return PTR_ERR(st);
1389	/*
1390	 * Don't update inode if the file type is different
1391	 */
1392	umode = p9mode2unixmode(v9ses, st, &rdev);
1393	if (inode_wrong_type(inode, umode))
1394		goto out;
1395
1396	/*
1397	 * We don't want to refresh inode->i_size,
1398	 * because we may have cached data
1399	 */
1400	flags = (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) ?
1401		V9FS_STAT2INODE_KEEP_ISIZE : 0;
1402	v9fs_stat2inode(st, inode, inode->i_sb, flags);
1403out:
1404	p9stat_free(st);
1405	kfree(st);
1406	return 0;
1407}
1408
1409static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1410	.create = v9fs_vfs_create,
1411	.lookup = v9fs_vfs_lookup,
1412	.atomic_open = v9fs_vfs_atomic_open,
1413	.symlink = v9fs_vfs_symlink,
1414	.link = v9fs_vfs_link,
1415	.unlink = v9fs_vfs_unlink,
1416	.mkdir = v9fs_vfs_mkdir,
1417	.rmdir = v9fs_vfs_rmdir,
1418	.mknod = v9fs_vfs_mknod,
1419	.rename = v9fs_vfs_rename,
1420	.getattr = v9fs_vfs_getattr,
1421	.setattr = v9fs_vfs_setattr,
1422};
1423
1424static const struct inode_operations v9fs_dir_inode_operations = {
1425	.create = v9fs_vfs_create,
1426	.lookup = v9fs_vfs_lookup,
1427	.atomic_open = v9fs_vfs_atomic_open,
1428	.unlink = v9fs_vfs_unlink,
1429	.mkdir = v9fs_vfs_mkdir,
1430	.rmdir = v9fs_vfs_rmdir,
1431	.mknod = v9fs_vfs_mknod,
1432	.rename = v9fs_vfs_rename,
1433	.getattr = v9fs_vfs_getattr,
1434	.setattr = v9fs_vfs_setattr,
1435};
1436
1437static const struct inode_operations v9fs_file_inode_operations = {
1438	.getattr = v9fs_vfs_getattr,
1439	.setattr = v9fs_vfs_setattr,
1440};
1441
1442static const struct inode_operations v9fs_symlink_inode_operations = {
1443	.get_link = v9fs_vfs_get_link,
1444	.getattr = v9fs_vfs_getattr,
1445	.setattr = v9fs_vfs_setattr,
1446};
1447