[mirror_ubuntu-bionic-kernel.git] / fs / fat / file.c

/*
 *  linux/fs/fat/file.c
 *
 *  Written 1992,1993 by Werner Almesberger
 *
 *  regular file handling primitives for fat-based filesystems
 */

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/compat.h>
#include <linux/mount.h>
#include <linux/time.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/blkdev.h>
#include <linux/fsnotify.h>
#include <linux/security.h>
#include "fat.h"

static int fat_ioctl_get_attributes(struct inode *inode, u32 __user *user_attr)
{
	u32 attr;

	mutex_lock(&inode->i_mutex);
	attr = fat_make_attrs(inode);
	mutex_unlock(&inode->i_mutex);

	return put_user(attr, user_attr);
}

static int fat_ioctl_set_attributes(struct file *file, u32 __user *user_attr)
{
	struct inode *inode = file->f_path.dentry->d_inode;
	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
	int is_dir = S_ISDIR(inode->i_mode);
	u32 attr, oldattr;
	struct iattr ia;
	int err;

	err = get_user(attr, user_attr);
	if (err)
		goto out;

	mutex_lock(&inode->i_mutex);
	err = mnt_want_write(file->f_path.mnt);
	if (err)
		goto out_unlock_inode;

	/*
	 * ATTR_VOLUME and ATTR_DIR cannot be changed; this also
	 * prevents the user from turning us into a VFAT
	 * longname entry.  Also, we obviously can't set
	 * any of the NTFS attributes in the high 24 bits.
	 */
	attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR);
	/* Merge in ATTR_VOLUME and ATTR_DIR */
	attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) |
		(is_dir ? ATTR_DIR : 0);
	oldattr = fat_make_attrs(inode);

	/* Equivalent to a chmod() */
	ia.ia_valid = ATTR_MODE | ATTR_CTIME;
	ia.ia_ctime = current_fs_time(inode->i_sb);
	if (is_dir)
		ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO);
	else {
		ia.ia_mode = fat_make_mode(sbi, attr,
			S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO));
	}

	/* The root directory has no attributes */
	if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
		err = -EINVAL;
		goto out_drop_write;
	}

	if (sbi->options.sys_immutable &&
	    ((attr | oldattr) & ATTR_SYS) &&
	    !capable(CAP_LINUX_IMMUTABLE)) {
		err = -EPERM;
		goto out_drop_write;
	}

	/*
	 * The security check is questionable...  We single
	 * out the RO attribute for checking by the security
	 * module, just because it maps to a file mode.
	 */
	err = security_inode_setattr(file->f_path.dentry, &ia);
	if (err)
		goto out_drop_write;

	/* This MUST be done before doing anything irreversible... */
	err = fat_setattr(file->f_path.dentry, &ia);
	if (err)
		goto out_drop_write;

	fsnotify_change(file->f_path.dentry, ia.ia_valid);
	if (sbi->options.sys_immutable) {
		if (attr & ATTR_SYS)
			inode->i_flags |= S_IMMUTABLE;
		else
			inode->i_flags &= ~S_IMMUTABLE;
	}

	fat_save_attrs(inode, attr);
	mark_inode_dirty(inode);
out_drop_write:
	mnt_drop_write(file->f_path.mnt);
out_unlock_inode:
	mutex_unlock(&inode->i_mutex);
out:
	return err;
}

long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	struct inode *inode = filp->f_path.dentry->d_inode;
	u32 __user *user_attr = (u32 __user *)arg;

	switch (cmd) {
	case FAT_IOCTL_GET_ATTRIBUTES:
		return fat_ioctl_get_attributes(inode, user_attr);
	case FAT_IOCTL_SET_ATTRIBUTES:
		return fat_ioctl_set_attributes(filp, user_attr);
	default:
		return -ENOTTY;	/* Inappropriate ioctl for device */
	}
}

#ifdef CONFIG_COMPAT
static long fat_generic_compat_ioctl(struct file *filp, unsigned int cmd,
				      unsigned long arg)

{
	return fat_generic_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
}
#endif

static int fat_file_release(struct inode *inode, struct file *filp)
{
	if ((filp->f_mode & FMODE_WRITE) &&
	     MSDOS_SB(inode->i_sb)->options.flush) {
		fat_flush_inodes(inode->i_sb, inode, NULL);
		congestion_wait(BLK_RW_ASYNC, HZ/10);
	}
	return 0;
}

int fat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
{
	struct inode *inode = filp->f_mapping->host;
	int res, err;

	res = generic_file_fsync(filp, start, end, datasync);
	err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping);

	return res ? res : err;
}


const struct file_operations fat_file_operations = {
	.llseek		= generic_file_llseek,
	.read		= do_sync_read,
	.write		= do_sync_write,
	.aio_read	= generic_file_aio_read,
	.aio_write	= generic_file_aio_write,
	.mmap		= generic_file_mmap,
	.release	= fat_file_release,
	.unlocked_ioctl	= fat_generic_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl	= fat_generic_compat_ioctl,
#endif
	.fsync		= fat_file_fsync,
	.splice_read	= generic_file_splice_read,
};

static int fat_cont_expand(struct inode *inode, loff_t size)
{
	struct address_space *mapping = inode->i_mapping;
	loff_t start = inode->i_size, count = size - inode->i_size;
	int err;

	err = generic_cont_expand_simple(inode, size);
	if (err)
		goto out;

	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
	mark_inode_dirty(inode);
	if (IS_SYNC(inode)) {
		int err2;

		/*
		 * Opencode syncing since we don't have a file open to use
		 * standard fsync path.
		 */
		err = filemap_fdatawrite_range(mapping, start,
					       start + count - 1);
		err2 = sync_mapping_buffers(mapping);
		if (!err)
			err = err2;
		err2 = write_inode_now(inode, 1);
		if (!err)
			err = err2;
		if (!err) {
			err =  filemap_fdatawait_range(mapping, start,
						       start + count - 1);
		}
	}
out:
	return err;
}

/* Free all clusters after the skip'th cluster. */
static int fat_free(struct inode *inode, int skip)
{
	struct super_block *sb = inode->i_sb;
	int err, wait, free_start, i_start, i_logstart;

	if (MSDOS_I(inode)->i_start == 0)
		return 0;

	fat_cache_inval_inode(inode);

	wait = IS_DIRSYNC(inode);
	i_start = free_start = MSDOS_I(inode)->i_start;
	i_logstart = MSDOS_I(inode)->i_logstart;

	/* First, we write the new file size. */
	if (!skip) {
		MSDOS_I(inode)->i_start = 0;
		MSDOS_I(inode)->i_logstart = 0;
	}
	MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
	if (wait) {
		err = fat_sync_inode(inode);
		if (err) {
			MSDOS_I(inode)->i_start = i_start;
			MSDOS_I(inode)->i_logstart = i_logstart;
			return err;
		}
	} else
		mark_inode_dirty(inode);

	/* Write a new EOF, and get the remaining cluster chain for freeing. */
	if (skip) {
		struct fat_entry fatent;
		int ret, fclus, dclus;

		ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
		if (ret < 0)
			return ret;
		else if (ret == FAT_ENT_EOF)
			return 0;

		fatent_init(&fatent);
		ret = fat_ent_read(inode, &fatent, dclus);
		if (ret == FAT_ENT_EOF) {
			fatent_brelse(&fatent);
			return 0;
		} else if (ret == FAT_ENT_FREE) {
			fat_fs_error(sb,
				     "%s: invalid cluster chain (i_pos %lld)",
				     __func__, MSDOS_I(inode)->i_pos);
			ret = -EIO;
		} else if (ret > 0) {
			err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
			if (err)
				ret = err;
		}
		fatent_brelse(&fatent);
		if (ret < 0)
			return ret;

		free_start = ret;
	}
	inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);

	/* Freeing the remained cluster chain */
	return fat_free_clusters(inode, free_start);
}

void fat_truncate_blocks(struct inode *inode, loff_t offset)
{
	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
	const unsigned int cluster_size = sbi->cluster_size;
	int nr_clusters;

	/*
	 * This protects against truncating a file bigger than it was then
	 * trying to write into the hole.
	 */
	if (MSDOS_I(inode)->mmu_private > offset)
		MSDOS_I(inode)->mmu_private = offset;

	nr_clusters = (offset + (cluster_size - 1)) >> sbi->cluster_bits;

	fat_free(inode, nr_clusters);
	fat_flush_inodes(inode->i_sb, inode, NULL);
}

int fat_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
	struct inode *inode = dentry->d_inode;
	generic_fillattr(inode, stat);
	stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
	return 0;
}
EXPORT_SYMBOL_GPL(fat_getattr);

static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
			     struct inode *inode, umode_t *mode_ptr)
{
	mode_t mask, perm;

	/*
	 * Note, the basic check is already done by a caller of
	 * (attr->ia_mode & ~FAT_VALID_MODE)
	 */

	if (S_ISREG(inode->i_mode))
		mask = sbi->options.fs_fmask;
	else
		mask = sbi->options.fs_dmask;

	perm = *mode_ptr & ~(S_IFMT | mask);

	/*
	 * Of the r and x bits, all (subject to umask) must be present. Of the
	 * w bits, either all (subject to umask) or none must be present.
	 *
	 * If fat_mode_can_hold_ro(inode) is false, can't change w bits.
	 */
	if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO)))
		return -EPERM;
	if (fat_mode_can_hold_ro(inode)) {
		if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask)))
			return -EPERM;
	} else {
		if ((perm & S_IWUGO) != (S_IWUGO & ~mask))
			return -EPERM;
	}

	*mode_ptr &= S_IFMT | perm;

	return 0;
}

static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
{
	mode_t allow_utime = sbi->options.allow_utime;

	if (current_fsuid() != inode->i_uid) {
		if (in_group_p(inode->i_gid))
			allow_utime >>= 3;
		if (allow_utime & MAY_WRITE)
			return 1;
	}

	/* use a default check */
	return 0;
}

#define TIMES_SET_FLAGS	(ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
/* valid file mode bits */
#define FAT_VALID_MODE	(S_IFREG | S_IFDIR | S_IRWXUGO)

int fat_setattr(struct dentry *dentry, struct iattr *attr)
{
	struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
	struct inode *inode = dentry->d_inode;
	unsigned int ia_valid;
	int error;

	/* Check for setting the inode time. */
	ia_valid = attr->ia_valid;
	if (ia_valid & TIMES_SET_FLAGS) {
		if (fat_allow_set_time(sbi, inode))
			attr->ia_valid &= ~TIMES_SET_FLAGS;
	}

	error = inode_change_ok(inode, attr);
	attr->ia_valid = ia_valid;
	if (error) {
		if (sbi->options.quiet)
			error = 0;
		goto out;
	}

	/*
	 * Expand the file. Since inode_setattr() updates ->i_size
	 * before calling the ->truncate(), but FAT needs to fill the
	 * hole before it. XXX: this is no longer true with new truncate
	 * sequence.
	 */
	if (attr->ia_valid & ATTR_SIZE) {
		inode_dio_wait(inode);

		if (attr->ia_size > inode->i_size) {
			error = fat_cont_expand(inode, attr->ia_size);
			if (error || attr->ia_valid == ATTR_SIZE)
				goto out;
			attr->ia_valid &= ~ATTR_SIZE;
		}
	}

	if (((attr->ia_valid & ATTR_UID) &&
	     (attr->ia_uid != sbi->options.fs_uid)) ||
	    ((attr->ia_valid & ATTR_GID) &&
	     (attr->ia_gid != sbi->options.fs_gid)) ||
	    ((attr->ia_valid & ATTR_MODE) &&
	     (attr->ia_mode & ~FAT_VALID_MODE)))
		error = -EPERM;

	if (error) {
		if (sbi->options.quiet)
			error = 0;
		goto out;
	}

	/*
	 * We don't return -EPERM here. Yes, strange, but this is too
	 * old behavior.
	 */
	if (attr->ia_valid & ATTR_MODE) {
		if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
			attr->ia_valid &= ~ATTR_MODE;
	}

	if (attr->ia_valid & ATTR_SIZE) {
		down_write(&MSDOS_I(inode)->truncate_lock);
		truncate_setsize(inode, attr->ia_size);
		fat_truncate_blocks(inode, attr->ia_size);
		up_write(&MSDOS_I(inode)->truncate_lock);
	}

	setattr_copy(inode, attr);
	mark_inode_dirty(inode);
out:
	return error;
}
EXPORT_SYMBOL_GPL(fat_setattr);

const struct inode_operations fat_file_inode_operations = {
	.setattr	= fat_setattr,
	.getattr	= fat_getattr,
};
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/fat/file.c
	3	*
	4	* Written 1992,1993 by Werner Almesberger
	5	*
	6	* regular file handling primitives for fat-based filesystems
	7	*/
	8
16f7e0fe	9	#include <linux/capability.h>
1da177e4	10	#include <linux/module.h>
7845bc3e	11	#include <linux/compat.h>
42a74f20	12	#include <linux/mount.h>
1da177e4	13	#include <linux/time.h>
1da177e4	14	#include <linux/buffer_head.h>
05eb0b51	15	#include <linux/writeback.h>
3fcfab16	16	#include <linux/backing-dev.h>
ae78bf9c	17	#include <linux/blkdev.h>
b1da47e2 MS	18	#include <linux/fsnotify.h>
b1da47e2 MS	19	#include <linux/security.h>
9e975dae	20	#include "fat.h"
1da177e4	21
21bea495 CH	22	static int fat_ioctl_get_attributes(struct inode inode, u32 __user user_attr)
	23	{
	24	u32 attr;
	25
	26	mutex_lock(&inode->i_mutex);
	27	attr = fat_make_attrs(inode);
	28	mutex_unlock(&inode->i_mutex);
	29
	30	return put_user(attr, user_attr);
	31	}
	32
	33	static int fat_ioctl_set_attributes(struct file file, u32 __user user_attr)
1da177e4	34	{
21bea495	35	struct inode *inode = file->f_path.dentry->d_inode;
1da177e4	36	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
21bea495 CH	37	int is_dir = S_ISDIR(inode->i_mode);
	38	u32 attr, oldattr;
	39	struct iattr ia;
	40	int err;
1da177e4	41
21bea495 CH	42	err = get_user(attr, user_attr);
	43	if (err)
	44	goto out;
1da177e4	45
21bea495 CH	46	mutex_lock(&inode->i_mutex);
	47	err = mnt_want_write(file->f_path.mnt);
	48	if (err)
	49	goto out_unlock_inode;
	50
	51	/*
	52	* ATTR_VOLUME and ATTR_DIR cannot be changed; this also
	53	* prevents the user from turning us into a VFAT
	54	* longname entry. Also, we obviously can't set
	55	* any of the NTFS attributes in the high 24 bits.
	56	*/
	57	attr &= 0xff & ~(ATTR_VOLUME \| ATTR_DIR);
	58	/* Merge in ATTR_VOLUME and ATTR_DIR */
	59	attr \|= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) \|
	60	(is_dir ? ATTR_DIR : 0);
	61	oldattr = fat_make_attrs(inode);
	62
	63	/* Equivalent to a chmod() */
	64	ia.ia_valid = ATTR_MODE \| ATTR_CTIME;
	65	ia.ia_ctime = current_fs_time(inode->i_sb);
	66	if (is_dir)
	67	ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO);
	68	else {
	69	ia.ia_mode = fat_make_mode(sbi, attr,
	70	S_IRUGO \| S_IWUGO \| (inode->i_mode & S_IXUGO));
	71	}
1da177e4	72
21bea495 CH	73	/* The root directory has no attributes */
	74	if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
	75	err = -EINVAL;
	76	goto out_drop_write;
1da177e4	77	}
1da177e4	78
21bea495 CH	79	if (sbi->options.sys_immutable &&
	80	((attr \| oldattr) & ATTR_SYS) &&
	81	!capable(CAP_LINUX_IMMUTABLE)) {
	82	err = -EPERM;
	83	goto out_drop_write;
	84	}
1da177e4	85
21bea495 CH	86	/*
	87	* The security check is questionable... We single
	88	* out the RO attribute for checking by the security
	89	* module, just because it maps to a file mode.
	90	*/
	91	err = security_inode_setattr(file->f_path.dentry, &ia);
	92	if (err)
	93	goto out_drop_write;
1da177e4	94
21bea495 CH	95	/* This MUST be done before doing anything irreversible... */
	96	err = fat_setattr(file->f_path.dentry, &ia);
	97	if (err)
	98	goto out_drop_write;
	99
	100	fsnotify_change(file->f_path.dentry, ia.ia_valid);
	101	if (sbi->options.sys_immutable) {
	102	if (attr & ATTR_SYS)
	103	inode->i_flags \|= S_IMMUTABLE;
	104	else
1adffbae	105	inode->i_flags &= ~S_IMMUTABLE;
21bea495	106	}
1da177e4	107
21bea495 CH	108	fat_save_attrs(inode, attr);
	109	mark_inode_dirty(inode);
	110	out_drop_write:
	111	mnt_drop_write(file->f_path.mnt);
	112	out_unlock_inode:
	113	mutex_unlock(&inode->i_mutex);
	114	out:
	115	return err;
	116	}
1da177e4	117
7845bc3e	118	long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
1da177e4	119	{
7845bc3e	120	struct inode *inode = filp->f_path.dentry->d_inode;
1da177e4	121	u32 __user user_attr = (u32 __user )arg;
1da177e4	122
1da177e4 LT	123	switch (cmd) {
1da177e4 LT	124	case FAT_IOCTL_GET_ATTRIBUTES:
21bea495	125	return fat_ioctl_get_attributes(inode, user_attr);
1da177e4	126	case FAT_IOCTL_SET_ATTRIBUTES:
21bea495	127	return fat_ioctl_set_attributes(filp, user_attr);
1da177e4 LT	128	default:
	129	return -ENOTTY; /* Inappropriate ioctl for device */
	130	}
	131	}
	132
7845bc3e AB	133	#ifdef CONFIG_COMPAT
	134	static long fat_generic_compat_ioctl(struct file *filp, unsigned int cmd,
	135	unsigned long arg)
	136
	137	{
	138	return fat_generic_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
	139	}
	140	#endif
	141
ae78bf9c CM	142	static int fat_file_release(struct inode inode, struct file filp)
	143	{
	144	if ((filp->f_mode & FMODE_WRITE) &&
	145	MSDOS_SB(inode->i_sb)->options.flush) {
	146	fat_flush_inodes(inode->i_sb, inode, NULL);
8aa7e847	147	congestion_wait(BLK_RW_ASYNC, HZ/10);
ae78bf9c CM	148	}
	149	return 0;
	150	}
	151
02c24a82	152	int fat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
b522412a	153	{
7ea80859	154	struct inode *inode = filp->f_mapping->host;
b522412a AV	155	int res, err;
b522412a AV	156
02c24a82	157	res = generic_file_fsync(filp, start, end, datasync);
b522412a AV	158	err = sync_mapping_buffers(MSDOS_SB(inode->i_sb)->fat_inode->i_mapping);
	159
	160	return res ? res : err;
	161	}
	162
	163
4b6f5d20	164	const struct file_operations fat_file_operations = {
1da177e4 LT	165	.llseek = generic_file_llseek,
	166	.read = do_sync_read,
	167	.write = do_sync_write,
1da177e4	168	.aio_read = generic_file_aio_read,
ef402268	169	.aio_write = generic_file_aio_write,
1da177e4	170	.mmap = generic_file_mmap,
ae78bf9c	171	.release = fat_file_release,
7845bc3e AB	172	.unlocked_ioctl = fat_generic_ioctl,
	173	#ifdef CONFIG_COMPAT
	174	.compat_ioctl = fat_generic_compat_ioctl,
	175	#endif
b522412a	176	.fsync = fat_file_fsync,
5ffc4ef4	177	.splice_read = generic_file_splice_read,
1da177e4 LT	178	};
1da177e4 LT	179
05eb0b51 OH	180	static int fat_cont_expand(struct inode *inode, loff_t size)
	181	{
	182	struct address_space *mapping = inode->i_mapping;
	183	loff_t start = inode->i_size, count = size - inode->i_size;
	184	int err;
	185
	186	err = generic_cont_expand_simple(inode, size);
	187	if (err)
	188	goto out;
	189
	190	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
	191	mark_inode_dirty(inode);
2f3d675b JK	192	if (IS_SYNC(inode)) {
	193	int err2;
	194
	195	/*
	196	* Opencode syncing since we don't have a file open to use
	197	* standard fsync path.
	198	*/
	199	err = filemap_fdatawrite_range(mapping, start,
	200	start + count - 1);
	201	err2 = sync_mapping_buffers(mapping);
	202	if (!err)
	203	err = err2;
	204	err2 = write_inode_now(inode, 1);
	205	if (!err)
	206	err = err2;
	207	if (!err) {
	208	err = filemap_fdatawait_range(mapping, start,
	209	start + count - 1);
	210	}
	211	}
05eb0b51 OH	212	out:
	213	return err;
	214	}
	215
1da177e4 LT	216	/* Free all clusters after the skip'th cluster. */
	217	static int fat_free(struct inode *inode, int skip)
	218	{
	219	struct super_block *sb = inode->i_sb;
	220	int err, wait, free_start, i_start, i_logstart;
	221
	222	if (MSDOS_I(inode)->i_start == 0)
	223	return 0;
	224
3b641407 OH	225	fat_cache_inval_inode(inode);
3b641407 OH	226
1da177e4	227	wait = IS_DIRSYNC(inode);
3b641407 OH	228	i_start = free_start = MSDOS_I(inode)->i_start;
	229	i_logstart = MSDOS_I(inode)->i_logstart;
	230
	231	/* First, we write the new file size. */
	232	if (!skip) {
	233	MSDOS_I(inode)->i_start = 0;
	234	MSDOS_I(inode)->i_logstart = 0;
	235	}
	236	MSDOS_I(inode)->i_attrs \|= ATTR_ARCH;
	237	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
	238	if (wait) {
	239	err = fat_sync_inode(inode);
	240	if (err) {
	241	MSDOS_I(inode)->i_start = i_start;
	242	MSDOS_I(inode)->i_logstart = i_logstart;
	243	return err;
	244	}
	245	} else
	246	mark_inode_dirty(inode);
	247
	248	/* Write a new EOF, and get the remaining cluster chain for freeing. */
1da177e4 LT	249	if (skip) {
	250	struct fat_entry fatent;
	251	int ret, fclus, dclus;
	252
	253	ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
	254	if (ret < 0)
	255	return ret;
	256	else if (ret == FAT_ENT_EOF)
	257	return 0;
	258
	259	fatent_init(&fatent);
	260	ret = fat_ent_read(inode, &fatent, dclus);
	261	if (ret == FAT_ENT_EOF) {
	262	fatent_brelse(&fatent);
	263	return 0;
	264	} else if (ret == FAT_ENT_FREE) {
85c78591	265	fat_fs_error(sb,
1da177e4	266	"%s: invalid cluster chain (i_pos %lld)",
8e24eea7	267	__func__, MSDOS_I(inode)->i_pos);
1da177e4 LT	268	ret = -EIO;
	269	} else if (ret > 0) {
	270	err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
	271	if (err)
	272	ret = err;
	273	}
	274	fatent_brelse(&fatent);
	275	if (ret < 0)
	276	return ret;
	277
	278	free_start = ret;
1da177e4	279	}
1da177e4 LT	280	inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
	281
	282	/* Freeing the remained cluster chain */
	283	return fat_free_clusters(inode, free_start);
1da177e4 LT	284	}
1da177e4 LT	285
459f6ed3	286	void fat_truncate_blocks(struct inode *inode, loff_t offset)
1da177e4	287	{
9c20616c	288	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1da177e4 LT	289	const unsigned int cluster_size = sbi->cluster_size;
	290	int nr_clusters;
	291
	292	/*
	293	* This protects against truncating a file bigger than it was then
	294	* trying to write into the hole.
	295	*/
459f6ed3	296	if (MSDOS_I(inode)->mmu_private > offset)
459f6ed3	297	MSDOS_I(inode)->mmu_private = offset;
1da177e4	298
459f6ed3	299	nr_clusters = (offset + (cluster_size - 1)) >> sbi->cluster_bits;
1da177e4	300
1da177e4	301	fat_free(inode, nr_clusters);
ae78bf9c	302	fat_flush_inodes(inode->i_sb, inode, NULL);
1da177e4 LT	303	}
1da177e4 LT	304
da63fc7c OH	305	int fat_getattr(struct vfsmount mnt, struct dentry dentry, struct kstat *stat)
	306	{
	307	struct inode *inode = dentry->d_inode;
	308	generic_fillattr(inode, stat);
	309	stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
	310	return 0;
	311	}
	312	EXPORT_SYMBOL_GPL(fat_getattr);
	313
2d518f84 OH	314	static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
2d518f84 OH	315	struct inode inode, umode_t mode_ptr)
1278fdd3	316	{
2d518f84	317	mode_t mask, perm;
1278fdd3	318
2d518f84 OH	319	/*
2d518f84 OH	320	* Note, the basic check is already done by a caller of
9c0aa1b8	321	* (attr->ia_mode & ~FAT_VALID_MODE)
2d518f84 OH	322	*/
	323
	324	if (S_ISREG(inode->i_mode))
1278fdd3 OH	325	mask = sbi->options.fs_fmask;
	326	else
	327	mask = sbi->options.fs_dmask;
	328
2d518f84 OH	329	perm = *mode_ptr & ~(S_IFMT \| mask);
2d518f84 OH	330
1278fdd3 OH	331	/*
	332	* Of the r and x bits, all (subject to umask) must be present. Of the
	333	* w bits, either all (subject to umask) or none must be present.
dfc209c0 OH	334	*
dfc209c0 OH	335	* If fat_mode_can_hold_ro(inode) is false, can't change w bits.
1278fdd3	336	*/
2d518f84	337	if ((perm & (S_IRUGO \| S_IXUGO)) != (inode->i_mode & (S_IRUGO\|S_IXUGO)))
1278fdd3	338	return -EPERM;
dfc209c0 OH	339	if (fat_mode_can_hold_ro(inode)) {
	340	if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask)))
	341	return -EPERM;
	342	} else {
	343	if ((perm & S_IWUGO) != (S_IWUGO & ~mask))
	344	return -EPERM;
	345	}
1278fdd3	346
2d518f84 OH	347	*mode_ptr &= S_IFMT \| perm;
2d518f84 OH	348
1278fdd3 OH	349	return 0;
	350	}
	351
1ae43f82 OH	352	static int fat_allow_set_time(struct msdos_sb_info sbi, struct inode inode)
	353	{
	354	mode_t allow_utime = sbi->options.allow_utime;
	355
f0ce7ee3	356	if (current_fsuid() != inode->i_uid) {
1ae43f82 OH	357	if (in_group_p(inode->i_gid))
	358	allow_utime >>= 3;
	359	if (allow_utime & MAY_WRITE)
	360	return 1;
	361	}
	362
	363	/* use a default check */
	364	return 0;
	365	}
	366
17263849	367	#define TIMES_SET_FLAGS (ATTR_MTIME_SET \| ATTR_ATIME_SET \| ATTR_TIMES_SET)
9c0aa1b8 OH	368	/* valid file mode bits */
9c0aa1b8 OH	369	#define FAT_VALID_MODE (S_IFREG \| S_IFDIR \| S_IRWXUGO)
17263849	370
1278fdd3 OH	371	int fat_setattr(struct dentry dentry, struct iattr attr)
	372	{
	373	struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
	374	struct inode *inode = dentry->d_inode;
1ae43f82	375	unsigned int ia_valid;
dfc209c0	376	int error;
1278fdd3	377
1ae43f82 OH	378	/* Check for setting the inode time. */
1ae43f82 OH	379	ia_valid = attr->ia_valid;
17263849	380	if (ia_valid & TIMES_SET_FLAGS) {
1ae43f82	381	if (fat_allow_set_time(sbi, inode))
17263849	382	attr->ia_valid &= ~TIMES_SET_FLAGS;
1ae43f82 OH	383	}
1ae43f82 OH	384
1278fdd3	385	error = inode_change_ok(inode, attr);
1ae43f82	386	attr->ia_valid = ia_valid;
1278fdd3 OH	387	if (error) {
	388	if (sbi->options.quiet)
	389	error = 0;
	390	goto out;
	391	}
2d518f84	392
db78b877 CH	393	/*
	394	* Expand the file. Since inode_setattr() updates ->i_size
	395	* before calling the ->truncate(), but FAT needs to fill the
	396	* hole before it. XXX: this is no longer true with new truncate
	397	* sequence.
	398	*/
	399	if (attr->ia_valid & ATTR_SIZE) {
562c72aa CH	400	inode_dio_wait(inode);
562c72aa CH	401
db78b877 CH	402	if (attr->ia_size > inode->i_size) {
	403	error = fat_cont_expand(inode, attr->ia_size);
	404	if (error \|\| attr->ia_valid == ATTR_SIZE)
	405	goto out;
	406	attr->ia_valid &= ~ATTR_SIZE;
	407	}
	408	}
	409
1278fdd3 OH	410	if (((attr->ia_valid & ATTR_UID) &&
	411	(attr->ia_uid != sbi->options.fs_uid)) \|\|
	412	((attr->ia_valid & ATTR_GID) &&
e97e8de3 OH	413	(attr->ia_gid != sbi->options.fs_gid)) \|\|
e97e8de3 OH	414	((attr->ia_valid & ATTR_MODE) &&
9c0aa1b8	415	(attr->ia_mode & ~FAT_VALID_MODE)))
1278fdd3 OH	416	error = -EPERM;
	417
	418	if (error) {
	419	if (sbi->options.quiet)
	420	error = 0;
	421	goto out;
	422	}
	423
2d518f84 OH	424	/*
	425	* We don't return -EPERM here. Yes, strange, but this is too
	426	* old behavior.
	427	*/
	428	if (attr->ia_valid & ATTR_MODE) {
	429	if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
	430	attr->ia_valid &= ~ATTR_MODE;
	431	}
1278fdd3	432
459f6ed3	433	if (attr->ia_valid & ATTR_SIZE) {
58268691	434	down_write(&MSDOS_I(inode)->truncate_lock);
2c27c65e CH	435	truncate_setsize(inode, attr->ia_size);
2c27c65e CH	436	fat_truncate_blocks(inode, attr->ia_size);
58268691	437	up_write(&MSDOS_I(inode)->truncate_lock);
459f6ed3	438	}
459f6ed3	439
6a1a90ad	440	setattr_copy(inode, attr);
459f6ed3	441	mark_inode_dirty(inode);
1278fdd3	442	out:
1278fdd3 OH	443	return error;
	444	}
	445	EXPORT_SYMBOL_GPL(fat_setattr);
	446
754661f1	447	const struct inode_operations fat_file_inode_operations = {
1278fdd3	448	.setattr = fat_setattr,
da63fc7c	449	.getattr = fat_getattr,
1da177e4	450	};