cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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inode.c (19072B)


      1/*
      2 *  linux/fs/hfs/inode.c
      3 *
      4 * Copyright (C) 1995-1997  Paul H. Hargrove
      5 * (C) 2003 Ardis Technologies <roman@ardistech.com>
      6 * This file may be distributed under the terms of the GNU General Public License.
      7 *
      8 * This file contains inode-related functions which do not depend on
      9 * which scheme is being used to represent forks.
     10 *
     11 * Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
     12 */
     13
     14#include <linux/pagemap.h>
     15#include <linux/mpage.h>
     16#include <linux/sched.h>
     17#include <linux/cred.h>
     18#include <linux/uio.h>
     19#include <linux/xattr.h>
     20#include <linux/blkdev.h>
     21
     22#include "hfs_fs.h"
     23#include "btree.h"
     24
     25static const struct file_operations hfs_file_operations;
     26static const struct inode_operations hfs_file_inode_operations;
     27
     28/*================ Variable-like macros ================*/
     29
     30#define HFS_VALID_MODE_BITS  (S_IFREG | S_IFDIR | S_IRWXUGO)
     31
     32static int hfs_writepage(struct page *page, struct writeback_control *wbc)
     33{
     34	return block_write_full_page(page, hfs_get_block, wbc);
     35}
     36
     37static int hfs_read_folio(struct file *file, struct folio *folio)
     38{
     39	return block_read_full_folio(folio, hfs_get_block);
     40}
     41
     42static void hfs_write_failed(struct address_space *mapping, loff_t to)
     43{
     44	struct inode *inode = mapping->host;
     45
     46	if (to > inode->i_size) {
     47		truncate_pagecache(inode, inode->i_size);
     48		hfs_file_truncate(inode);
     49	}
     50}
     51
     52int hfs_write_begin(struct file *file, struct address_space *mapping,
     53		loff_t pos, unsigned len, struct page **pagep, void **fsdata)
     54{
     55	int ret;
     56
     57	*pagep = NULL;
     58	ret = cont_write_begin(file, mapping, pos, len, pagep, fsdata,
     59				hfs_get_block,
     60				&HFS_I(mapping->host)->phys_size);
     61	if (unlikely(ret))
     62		hfs_write_failed(mapping, pos + len);
     63
     64	return ret;
     65}
     66
     67static sector_t hfs_bmap(struct address_space *mapping, sector_t block)
     68{
     69	return generic_block_bmap(mapping, block, hfs_get_block);
     70}
     71
     72static bool hfs_release_folio(struct folio *folio, gfp_t mask)
     73{
     74	struct inode *inode = folio->mapping->host;
     75	struct super_block *sb = inode->i_sb;
     76	struct hfs_btree *tree;
     77	struct hfs_bnode *node;
     78	u32 nidx;
     79	int i;
     80	bool res = true;
     81
     82	switch (inode->i_ino) {
     83	case HFS_EXT_CNID:
     84		tree = HFS_SB(sb)->ext_tree;
     85		break;
     86	case HFS_CAT_CNID:
     87		tree = HFS_SB(sb)->cat_tree;
     88		break;
     89	default:
     90		BUG();
     91		return false;
     92	}
     93
     94	if (!tree)
     95		return false;
     96
     97	if (tree->node_size >= PAGE_SIZE) {
     98		nidx = folio->index >> (tree->node_size_shift - PAGE_SHIFT);
     99		spin_lock(&tree->hash_lock);
    100		node = hfs_bnode_findhash(tree, nidx);
    101		if (!node)
    102			;
    103		else if (atomic_read(&node->refcnt))
    104			res = false;
    105		if (res && node) {
    106			hfs_bnode_unhash(node);
    107			hfs_bnode_free(node);
    108		}
    109		spin_unlock(&tree->hash_lock);
    110	} else {
    111		nidx = folio->index << (PAGE_SHIFT - tree->node_size_shift);
    112		i = 1 << (PAGE_SHIFT - tree->node_size_shift);
    113		spin_lock(&tree->hash_lock);
    114		do {
    115			node = hfs_bnode_findhash(tree, nidx++);
    116			if (!node)
    117				continue;
    118			if (atomic_read(&node->refcnt)) {
    119				res = false;
    120				break;
    121			}
    122			hfs_bnode_unhash(node);
    123			hfs_bnode_free(node);
    124		} while (--i && nidx < tree->node_count);
    125		spin_unlock(&tree->hash_lock);
    126	}
    127	return res ? try_to_free_buffers(folio) : false;
    128}
    129
    130static ssize_t hfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
    131{
    132	struct file *file = iocb->ki_filp;
    133	struct address_space *mapping = file->f_mapping;
    134	struct inode *inode = mapping->host;
    135	size_t count = iov_iter_count(iter);
    136	ssize_t ret;
    137
    138	ret = blockdev_direct_IO(iocb, inode, iter, hfs_get_block);
    139
    140	/*
    141	 * In case of error extending write may have instantiated a few
    142	 * blocks outside i_size. Trim these off again.
    143	 */
    144	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
    145		loff_t isize = i_size_read(inode);
    146		loff_t end = iocb->ki_pos + count;
    147
    148		if (end > isize)
    149			hfs_write_failed(mapping, end);
    150	}
    151
    152	return ret;
    153}
    154
    155static int hfs_writepages(struct address_space *mapping,
    156			  struct writeback_control *wbc)
    157{
    158	return mpage_writepages(mapping, wbc, hfs_get_block);
    159}
    160
    161const struct address_space_operations hfs_btree_aops = {
    162	.dirty_folio	= block_dirty_folio,
    163	.invalidate_folio = block_invalidate_folio,
    164	.read_folio	= hfs_read_folio,
    165	.writepage	= hfs_writepage,
    166	.write_begin	= hfs_write_begin,
    167	.write_end	= generic_write_end,
    168	.bmap		= hfs_bmap,
    169	.release_folio	= hfs_release_folio,
    170};
    171
    172const struct address_space_operations hfs_aops = {
    173	.dirty_folio	= block_dirty_folio,
    174	.invalidate_folio = block_invalidate_folio,
    175	.read_folio	= hfs_read_folio,
    176	.writepage	= hfs_writepage,
    177	.write_begin	= hfs_write_begin,
    178	.write_end	= generic_write_end,
    179	.bmap		= hfs_bmap,
    180	.direct_IO	= hfs_direct_IO,
    181	.writepages	= hfs_writepages,
    182};
    183
    184/*
    185 * hfs_new_inode
    186 */
    187struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t mode)
    188{
    189	struct super_block *sb = dir->i_sb;
    190	struct inode *inode = new_inode(sb);
    191	if (!inode)
    192		return NULL;
    193
    194	mutex_init(&HFS_I(inode)->extents_lock);
    195	INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
    196	spin_lock_init(&HFS_I(inode)->open_dir_lock);
    197	hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
    198	inode->i_ino = HFS_SB(sb)->next_id++;
    199	inode->i_mode = mode;
    200	inode->i_uid = current_fsuid();
    201	inode->i_gid = current_fsgid();
    202	set_nlink(inode, 1);
    203	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
    204	HFS_I(inode)->flags = 0;
    205	HFS_I(inode)->rsrc_inode = NULL;
    206	HFS_I(inode)->fs_blocks = 0;
    207	if (S_ISDIR(mode)) {
    208		inode->i_size = 2;
    209		HFS_SB(sb)->folder_count++;
    210		if (dir->i_ino == HFS_ROOT_CNID)
    211			HFS_SB(sb)->root_dirs++;
    212		inode->i_op = &hfs_dir_inode_operations;
    213		inode->i_fop = &hfs_dir_operations;
    214		inode->i_mode |= S_IRWXUGO;
    215		inode->i_mode &= ~HFS_SB(inode->i_sb)->s_dir_umask;
    216	} else if (S_ISREG(mode)) {
    217		HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
    218		HFS_SB(sb)->file_count++;
    219		if (dir->i_ino == HFS_ROOT_CNID)
    220			HFS_SB(sb)->root_files++;
    221		inode->i_op = &hfs_file_inode_operations;
    222		inode->i_fop = &hfs_file_operations;
    223		inode->i_mapping->a_ops = &hfs_aops;
    224		inode->i_mode |= S_IRUGO|S_IXUGO;
    225		if (mode & S_IWUSR)
    226			inode->i_mode |= S_IWUGO;
    227		inode->i_mode &= ~HFS_SB(inode->i_sb)->s_file_umask;
    228		HFS_I(inode)->phys_size = 0;
    229		HFS_I(inode)->alloc_blocks = 0;
    230		HFS_I(inode)->first_blocks = 0;
    231		HFS_I(inode)->cached_start = 0;
    232		HFS_I(inode)->cached_blocks = 0;
    233		memset(HFS_I(inode)->first_extents, 0, sizeof(hfs_extent_rec));
    234		memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
    235	}
    236	insert_inode_hash(inode);
    237	mark_inode_dirty(inode);
    238	set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
    239	hfs_mark_mdb_dirty(sb);
    240
    241	return inode;
    242}
    243
    244void hfs_delete_inode(struct inode *inode)
    245{
    246	struct super_block *sb = inode->i_sb;
    247
    248	hfs_dbg(INODE, "delete_inode: %lu\n", inode->i_ino);
    249	if (S_ISDIR(inode->i_mode)) {
    250		HFS_SB(sb)->folder_count--;
    251		if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
    252			HFS_SB(sb)->root_dirs--;
    253		set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
    254		hfs_mark_mdb_dirty(sb);
    255		return;
    256	}
    257	HFS_SB(sb)->file_count--;
    258	if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
    259		HFS_SB(sb)->root_files--;
    260	if (S_ISREG(inode->i_mode)) {
    261		if (!inode->i_nlink) {
    262			inode->i_size = 0;
    263			hfs_file_truncate(inode);
    264		}
    265	}
    266	set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
    267	hfs_mark_mdb_dirty(sb);
    268}
    269
    270void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
    271			 __be32 __log_size, __be32 phys_size, u32 clump_size)
    272{
    273	struct super_block *sb = inode->i_sb;
    274	u32 log_size = be32_to_cpu(__log_size);
    275	u16 count;
    276	int i;
    277
    278	memcpy(HFS_I(inode)->first_extents, ext, sizeof(hfs_extent_rec));
    279	for (count = 0, i = 0; i < 3; i++)
    280		count += be16_to_cpu(ext[i].count);
    281	HFS_I(inode)->first_blocks = count;
    282
    283	inode->i_size = HFS_I(inode)->phys_size = log_size;
    284	HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
    285	inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
    286	HFS_I(inode)->alloc_blocks = be32_to_cpu(phys_size) /
    287				     HFS_SB(sb)->alloc_blksz;
    288	HFS_I(inode)->clump_blocks = clump_size / HFS_SB(sb)->alloc_blksz;
    289	if (!HFS_I(inode)->clump_blocks)
    290		HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
    291}
    292
    293struct hfs_iget_data {
    294	struct hfs_cat_key *key;
    295	hfs_cat_rec *rec;
    296};
    297
    298static int hfs_test_inode(struct inode *inode, void *data)
    299{
    300	struct hfs_iget_data *idata = data;
    301	hfs_cat_rec *rec;
    302
    303	rec = idata->rec;
    304	switch (rec->type) {
    305	case HFS_CDR_DIR:
    306		return inode->i_ino == be32_to_cpu(rec->dir.DirID);
    307	case HFS_CDR_FIL:
    308		return inode->i_ino == be32_to_cpu(rec->file.FlNum);
    309	default:
    310		BUG();
    311		return 1;
    312	}
    313}
    314
    315/*
    316 * hfs_read_inode
    317 */
    318static int hfs_read_inode(struct inode *inode, void *data)
    319{
    320	struct hfs_iget_data *idata = data;
    321	struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
    322	hfs_cat_rec *rec;
    323
    324	HFS_I(inode)->flags = 0;
    325	HFS_I(inode)->rsrc_inode = NULL;
    326	mutex_init(&HFS_I(inode)->extents_lock);
    327	INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
    328	spin_lock_init(&HFS_I(inode)->open_dir_lock);
    329
    330	/* Initialize the inode */
    331	inode->i_uid = hsb->s_uid;
    332	inode->i_gid = hsb->s_gid;
    333	set_nlink(inode, 1);
    334
    335	if (idata->key)
    336		HFS_I(inode)->cat_key = *idata->key;
    337	else
    338		HFS_I(inode)->flags |= HFS_FLG_RSRC;
    339	HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60;
    340
    341	rec = idata->rec;
    342	switch (rec->type) {
    343	case HFS_CDR_FIL:
    344		if (!HFS_IS_RSRC(inode)) {
    345			hfs_inode_read_fork(inode, rec->file.ExtRec, rec->file.LgLen,
    346					    rec->file.PyLen, be16_to_cpu(rec->file.ClpSize));
    347		} else {
    348			hfs_inode_read_fork(inode, rec->file.RExtRec, rec->file.RLgLen,
    349					    rec->file.RPyLen, be16_to_cpu(rec->file.ClpSize));
    350		}
    351
    352		inode->i_ino = be32_to_cpu(rec->file.FlNum);
    353		inode->i_mode = S_IRUGO | S_IXUGO;
    354		if (!(rec->file.Flags & HFS_FIL_LOCK))
    355			inode->i_mode |= S_IWUGO;
    356		inode->i_mode &= ~hsb->s_file_umask;
    357		inode->i_mode |= S_IFREG;
    358		inode->i_ctime = inode->i_atime = inode->i_mtime =
    359				hfs_m_to_utime(rec->file.MdDat);
    360		inode->i_op = &hfs_file_inode_operations;
    361		inode->i_fop = &hfs_file_operations;
    362		inode->i_mapping->a_ops = &hfs_aops;
    363		break;
    364	case HFS_CDR_DIR:
    365		inode->i_ino = be32_to_cpu(rec->dir.DirID);
    366		inode->i_size = be16_to_cpu(rec->dir.Val) + 2;
    367		HFS_I(inode)->fs_blocks = 0;
    368		inode->i_mode = S_IFDIR | (S_IRWXUGO & ~hsb->s_dir_umask);
    369		inode->i_ctime = inode->i_atime = inode->i_mtime =
    370				hfs_m_to_utime(rec->dir.MdDat);
    371		inode->i_op = &hfs_dir_inode_operations;
    372		inode->i_fop = &hfs_dir_operations;
    373		break;
    374	default:
    375		make_bad_inode(inode);
    376	}
    377	return 0;
    378}
    379
    380/*
    381 * __hfs_iget()
    382 *
    383 * Given the MDB for a HFS filesystem, a 'key' and an 'entry' in
    384 * the catalog B-tree and the 'type' of the desired file return the
    385 * inode for that file/directory or NULL.  Note that 'type' indicates
    386 * whether we want the actual file or directory, or the corresponding
    387 * metadata (AppleDouble header file or CAP metadata file).
    388 */
    389struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key, hfs_cat_rec *rec)
    390{
    391	struct hfs_iget_data data = { key, rec };
    392	struct inode *inode;
    393	u32 cnid;
    394
    395	switch (rec->type) {
    396	case HFS_CDR_DIR:
    397		cnid = be32_to_cpu(rec->dir.DirID);
    398		break;
    399	case HFS_CDR_FIL:
    400		cnid = be32_to_cpu(rec->file.FlNum);
    401		break;
    402	default:
    403		return NULL;
    404	}
    405	inode = iget5_locked(sb, cnid, hfs_test_inode, hfs_read_inode, &data);
    406	if (inode && (inode->i_state & I_NEW))
    407		unlock_new_inode(inode);
    408	return inode;
    409}
    410
    411void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
    412			  __be32 *log_size, __be32 *phys_size)
    413{
    414	memcpy(ext, HFS_I(inode)->first_extents, sizeof(hfs_extent_rec));
    415
    416	if (log_size)
    417		*log_size = cpu_to_be32(inode->i_size);
    418	if (phys_size)
    419		*phys_size = cpu_to_be32(HFS_I(inode)->alloc_blocks *
    420					 HFS_SB(inode->i_sb)->alloc_blksz);
    421}
    422
    423int hfs_write_inode(struct inode *inode, struct writeback_control *wbc)
    424{
    425	struct inode *main_inode = inode;
    426	struct hfs_find_data fd;
    427	hfs_cat_rec rec;
    428	int res;
    429
    430	hfs_dbg(INODE, "hfs_write_inode: %lu\n", inode->i_ino);
    431	res = hfs_ext_write_extent(inode);
    432	if (res)
    433		return res;
    434
    435	if (inode->i_ino < HFS_FIRSTUSER_CNID) {
    436		switch (inode->i_ino) {
    437		case HFS_ROOT_CNID:
    438			break;
    439		case HFS_EXT_CNID:
    440			hfs_btree_write(HFS_SB(inode->i_sb)->ext_tree);
    441			return 0;
    442		case HFS_CAT_CNID:
    443			hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
    444			return 0;
    445		default:
    446			BUG();
    447			return -EIO;
    448		}
    449	}
    450
    451	if (HFS_IS_RSRC(inode))
    452		main_inode = HFS_I(inode)->rsrc_inode;
    453
    454	if (!main_inode->i_nlink)
    455		return 0;
    456
    457	if (hfs_find_init(HFS_SB(main_inode->i_sb)->cat_tree, &fd))
    458		/* panic? */
    459		return -EIO;
    460
    461	fd.search_key->cat = HFS_I(main_inode)->cat_key;
    462	if (hfs_brec_find(&fd))
    463		/* panic? */
    464		goto out;
    465
    466	if (S_ISDIR(main_inode->i_mode)) {
    467		WARN_ON(fd.entrylength < sizeof(struct hfs_cat_dir));
    468		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
    469			   sizeof(struct hfs_cat_dir));
    470		if (rec.type != HFS_CDR_DIR ||
    471		    be32_to_cpu(rec.dir.DirID) != inode->i_ino) {
    472		}
    473
    474		rec.dir.MdDat = hfs_u_to_mtime(inode->i_mtime);
    475		rec.dir.Val = cpu_to_be16(inode->i_size - 2);
    476
    477		hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
    478			    sizeof(struct hfs_cat_dir));
    479	} else if (HFS_IS_RSRC(inode)) {
    480		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
    481			       sizeof(struct hfs_cat_file));
    482		hfs_inode_write_fork(inode, rec.file.RExtRec,
    483				     &rec.file.RLgLen, &rec.file.RPyLen);
    484		hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
    485				sizeof(struct hfs_cat_file));
    486	} else {
    487		WARN_ON(fd.entrylength < sizeof(struct hfs_cat_file));
    488		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
    489			   sizeof(struct hfs_cat_file));
    490		if (rec.type != HFS_CDR_FIL ||
    491		    be32_to_cpu(rec.file.FlNum) != inode->i_ino) {
    492		}
    493
    494		if (inode->i_mode & S_IWUSR)
    495			rec.file.Flags &= ~HFS_FIL_LOCK;
    496		else
    497			rec.file.Flags |= HFS_FIL_LOCK;
    498		hfs_inode_write_fork(inode, rec.file.ExtRec, &rec.file.LgLen, &rec.file.PyLen);
    499		rec.file.MdDat = hfs_u_to_mtime(inode->i_mtime);
    500
    501		hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
    502			    sizeof(struct hfs_cat_file));
    503	}
    504out:
    505	hfs_find_exit(&fd);
    506	return 0;
    507}
    508
    509static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
    510				      unsigned int flags)
    511{
    512	struct inode *inode = NULL;
    513	hfs_cat_rec rec;
    514	struct hfs_find_data fd;
    515	int res;
    516
    517	if (HFS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
    518		goto out;
    519
    520	inode = HFS_I(dir)->rsrc_inode;
    521	if (inode)
    522		goto out;
    523
    524	inode = new_inode(dir->i_sb);
    525	if (!inode)
    526		return ERR_PTR(-ENOMEM);
    527
    528	res = hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
    529	if (res) {
    530		iput(inode);
    531		return ERR_PTR(res);
    532	}
    533	fd.search_key->cat = HFS_I(dir)->cat_key;
    534	res = hfs_brec_read(&fd, &rec, sizeof(rec));
    535	if (!res) {
    536		struct hfs_iget_data idata = { NULL, &rec };
    537		hfs_read_inode(inode, &idata);
    538	}
    539	hfs_find_exit(&fd);
    540	if (res) {
    541		iput(inode);
    542		return ERR_PTR(res);
    543	}
    544	HFS_I(inode)->rsrc_inode = dir;
    545	HFS_I(dir)->rsrc_inode = inode;
    546	igrab(dir);
    547	inode_fake_hash(inode);
    548	mark_inode_dirty(inode);
    549	dont_mount(dentry);
    550out:
    551	return d_splice_alias(inode, dentry);
    552}
    553
    554void hfs_evict_inode(struct inode *inode)
    555{
    556	truncate_inode_pages_final(&inode->i_data);
    557	clear_inode(inode);
    558	if (HFS_IS_RSRC(inode) && HFS_I(inode)->rsrc_inode) {
    559		HFS_I(HFS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
    560		iput(HFS_I(inode)->rsrc_inode);
    561	}
    562}
    563
    564static int hfs_file_open(struct inode *inode, struct file *file)
    565{
    566	if (HFS_IS_RSRC(inode))
    567		inode = HFS_I(inode)->rsrc_inode;
    568	atomic_inc(&HFS_I(inode)->opencnt);
    569	return 0;
    570}
    571
    572static int hfs_file_release(struct inode *inode, struct file *file)
    573{
    574	//struct super_block *sb = inode->i_sb;
    575
    576	if (HFS_IS_RSRC(inode))
    577		inode = HFS_I(inode)->rsrc_inode;
    578	if (atomic_dec_and_test(&HFS_I(inode)->opencnt)) {
    579		inode_lock(inode);
    580		hfs_file_truncate(inode);
    581		//if (inode->i_flags & S_DEAD) {
    582		//	hfs_delete_cat(inode->i_ino, HFSPLUS_SB(sb).hidden_dir, NULL);
    583		//	hfs_delete_inode(inode);
    584		//}
    585		inode_unlock(inode);
    586	}
    587	return 0;
    588}
    589
    590/*
    591 * hfs_notify_change()
    592 *
    593 * Based very closely on fs/msdos/inode.c by Werner Almesberger
    594 *
    595 * This is the notify_change() field in the super_operations structure
    596 * for HFS file systems.  The purpose is to take that changes made to
    597 * an inode and apply then in a filesystem-dependent manner.  In this
    598 * case the process has a few of tasks to do:
    599 *  1) prevent changes to the i_uid and i_gid fields.
    600 *  2) map file permissions to the closest allowable permissions
    601 *  3) Since multiple Linux files can share the same on-disk inode under
    602 *     HFS (for instance the data and resource forks of a file) a change
    603 *     to permissions must be applied to all other in-core inodes which
    604 *     correspond to the same HFS file.
    605 */
    606
    607int hfs_inode_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
    608		      struct iattr *attr)
    609{
    610	struct inode *inode = d_inode(dentry);
    611	struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
    612	int error;
    613
    614	error = setattr_prepare(&init_user_ns, dentry,
    615				attr); /* basic permission checks */
    616	if (error)
    617		return error;
    618
    619	/* no uig/gid changes and limit which mode bits can be set */
    620	if (((attr->ia_valid & ATTR_UID) &&
    621	     (!uid_eq(attr->ia_uid, hsb->s_uid))) ||
    622	    ((attr->ia_valid & ATTR_GID) &&
    623	     (!gid_eq(attr->ia_gid, hsb->s_gid))) ||
    624	    ((attr->ia_valid & ATTR_MODE) &&
    625	     ((S_ISDIR(inode->i_mode) &&
    626	       (attr->ia_mode != inode->i_mode)) ||
    627	      (attr->ia_mode & ~HFS_VALID_MODE_BITS)))) {
    628		return hsb->s_quiet ? 0 : error;
    629	}
    630
    631	if (attr->ia_valid & ATTR_MODE) {
    632		/* Only the 'w' bits can ever change and only all together. */
    633		if (attr->ia_mode & S_IWUSR)
    634			attr->ia_mode = inode->i_mode | S_IWUGO;
    635		else
    636			attr->ia_mode = inode->i_mode & ~S_IWUGO;
    637		attr->ia_mode &= S_ISDIR(inode->i_mode) ? ~hsb->s_dir_umask: ~hsb->s_file_umask;
    638	}
    639
    640	if ((attr->ia_valid & ATTR_SIZE) &&
    641	    attr->ia_size != i_size_read(inode)) {
    642		inode_dio_wait(inode);
    643
    644		error = inode_newsize_ok(inode, attr->ia_size);
    645		if (error)
    646			return error;
    647
    648		truncate_setsize(inode, attr->ia_size);
    649		hfs_file_truncate(inode);
    650		inode->i_atime = inode->i_mtime = inode->i_ctime =
    651						  current_time(inode);
    652	}
    653
    654	setattr_copy(&init_user_ns, inode, attr);
    655	mark_inode_dirty(inode);
    656	return 0;
    657}
    658
    659static int hfs_file_fsync(struct file *filp, loff_t start, loff_t end,
    660			  int datasync)
    661{
    662	struct inode *inode = filp->f_mapping->host;
    663	struct super_block * sb;
    664	int ret, err;
    665
    666	ret = file_write_and_wait_range(filp, start, end);
    667	if (ret)
    668		return ret;
    669	inode_lock(inode);
    670
    671	/* sync the inode to buffers */
    672	ret = write_inode_now(inode, 0);
    673
    674	/* sync the superblock to buffers */
    675	sb = inode->i_sb;
    676	flush_delayed_work(&HFS_SB(sb)->mdb_work);
    677	/* .. finally sync the buffers to disk */
    678	err = sync_blockdev(sb->s_bdev);
    679	if (!ret)
    680		ret = err;
    681	inode_unlock(inode);
    682	return ret;
    683}
    684
    685static const struct file_operations hfs_file_operations = {
    686	.llseek		= generic_file_llseek,
    687	.read_iter	= generic_file_read_iter,
    688	.write_iter	= generic_file_write_iter,
    689	.mmap		= generic_file_mmap,
    690	.splice_read	= generic_file_splice_read,
    691	.fsync		= hfs_file_fsync,
    692	.open		= hfs_file_open,
    693	.release	= hfs_file_release,
    694};
    695
    696static const struct inode_operations hfs_file_inode_operations = {
    697	.lookup		= hfs_file_lookup,
    698	.setattr	= hfs_inode_setattr,
    699	.listxattr	= generic_listxattr,
    700};