[mirror_ubuntu-artful-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/time.h>
#include <linux/msdos_fs.h>
#include <linux/smp_lock.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/blkdev.h>

int fat_generic_ioctl(struct inode *inode, struct file *filp,
		      unsigned int cmd, unsigned long arg)
{
	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
	u32 __user *user_attr = (u32 __user *)arg;

	switch (cmd) {
	case FAT_IOCTL_GET_ATTRIBUTES:
	{
		u32 attr;

		if (inode->i_ino == MSDOS_ROOT_INO)
			attr = ATTR_DIR;
		else
			attr = fat_attr(inode);

		return put_user(attr, user_attr);
	}
	case FAT_IOCTL_SET_ATTRIBUTES:
	{
		u32 attr, oldattr;
		int err, is_dir = S_ISDIR(inode->i_mode);
		struct iattr ia;

		err = get_user(attr, user_attr);
		if (err)
			return err;

		mutex_lock(&inode->i_mutex);

		if (IS_RDONLY(inode)) {
			err = -EROFS;
			goto up;
		}

		/*
		 * 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_attr(inode);

		/* Equivalent to a chmod() */
		ia.ia_valid = ATTR_MODE | ATTR_CTIME;
		if (is_dir) {
			ia.ia_mode = MSDOS_MKMODE(attr,
				S_IRWXUGO & ~sbi->options.fs_dmask)
				| S_IFDIR;
		} else {
			ia.ia_mode = MSDOS_MKMODE(attr,
				(S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO))
				& ~sbi->options.fs_fmask)
				| S_IFREG;
		}

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

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

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

		if (sbi->options.sys_immutable) {
			if (attr & ATTR_SYS)
				inode->i_flags |= S_IMMUTABLE;
			else
				inode->i_flags &= S_IMMUTABLE;
		}

		MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED;
		mark_inode_dirty(inode);
	up:
		mutex_unlock(&inode->i_mutex);
		return err;
	}
	default:
		return -ENOTTY;	/* Inappropriate ioctl for device */
	}
}

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(WRITE, HZ/10);
	}
	return 0;
}

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,
	.ioctl		= fat_generic_ioctl,
	.fsync		= file_fsync,
	.sendfile	= generic_file_sendfile,
};

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))
		err = sync_page_range_nolock(inode, mapping, start, count);
out:
	return err;
}

int fat_notify_change(struct dentry *dentry, struct iattr *attr)
{
	struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
	struct inode *inode = dentry->d_inode;
	int mask, error = 0;

	lock_kernel();

	/*
	 * Expand the file. Since inode_setattr() updates ->i_size
	 * before calling the ->truncate(), but FAT needs to fill the
	 * hole before it.
	 */
	if (attr->ia_valid & ATTR_SIZE) {
		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;
		}
	}

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

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

	if (S_ISDIR(inode->i_mode))
		mask = sbi->options.fs_dmask;
	else
		mask = sbi->options.fs_fmask;
	inode->i_mode &= S_IFMT | (S_IRWXUGO & ~mask);
out:
	unlock_kernel();
	return error;
}

EXPORT_SYMBOL_GPL(fat_notify_change);

/* 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_panic(sb,
				     "%s: invalid cluster chain (i_pos %lld)",
				     __FUNCTION__, 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(struct inode *inode)
{
	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 > inode->i_size)
		MSDOS_I(inode)->mmu_private = inode->i_size;

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

	lock_kernel();
	fat_free(inode, nr_clusters);
	unlock_kernel();
	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);

const struct inode_operations fat_file_inode_operations = {
	.truncate	= fat_truncate,
	.setattr	= fat_notify_change,
	.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 LT	10	#include <linux/module.h>
	11	#include <linux/time.h>
	12	#include <linux/msdos_fs.h>
	13	#include <linux/smp_lock.h>
	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>
1da177e4	18
1da177e4 LT	19	int fat_generic_ioctl(struct inode inode, struct file filp,
	20	unsigned int cmd, unsigned long arg)
	21	{
	22	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
	23	u32 __user user_attr = (u32 __user )arg;
	24
	25	switch (cmd) {
	26	case FAT_IOCTL_GET_ATTRIBUTES:
	27	{
	28	u32 attr;
	29
	30	if (inode->i_ino == MSDOS_ROOT_INO)
	31	attr = ATTR_DIR;
	32	else
	33	attr = fat_attr(inode);
	34
	35	return put_user(attr, user_attr);
	36	}
	37	case FAT_IOCTL_SET_ATTRIBUTES:
	38	{
	39	u32 attr, oldattr;
	40	int err, is_dir = S_ISDIR(inode->i_mode);
	41	struct iattr ia;
	42
	43	err = get_user(attr, user_attr);
	44	if (err)
	45	return err;
	46
1b1dcc1b	47	mutex_lock(&inode->i_mutex);
1da177e4 LT	48
	49	if (IS_RDONLY(inode)) {
	50	err = -EROFS;
	51	goto up;
	52	}
	53
	54	/*
	55	* ATTR_VOLUME and ATTR_DIR cannot be changed; this also
	56	* prevents the user from turning us into a VFAT
	57	* longname entry. Also, we obviously can't set
	58	* any of the NTFS attributes in the high 24 bits.
	59	*/
	60	attr &= 0xff & ~(ATTR_VOLUME \| ATTR_DIR);
	61	/* Merge in ATTR_VOLUME and ATTR_DIR */
	62	attr \|= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) \|
	63	(is_dir ? ATTR_DIR : 0);
	64	oldattr = fat_attr(inode);
	65
	66	/* Equivalent to a chmod() */
	67	ia.ia_valid = ATTR_MODE \| ATTR_CTIME;
	68	if (is_dir) {
	69	ia.ia_mode = MSDOS_MKMODE(attr,
	70	S_IRWXUGO & ~sbi->options.fs_dmask)
	71	\| S_IFDIR;
	72	} else {
	73	ia.ia_mode = MSDOS_MKMODE(attr,
	74	(S_IRUGO \| S_IWUGO \| (inode->i_mode & S_IXUGO))
	75	& ~sbi->options.fs_fmask)
	76	\| S_IFREG;
	77	}
	78
	79	/* The root directory has no attributes */
	80	if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
	81	err = -EINVAL;
	82	goto up;
	83	}
	84
	85	if (sbi->options.sys_immutable) {
	86	if ((attr \| oldattr) & ATTR_SYS) {
	87	if (!capable(CAP_LINUX_IMMUTABLE)) {
	88	err = -EPERM;
	89	goto up;
	90	}
	91	}
	92	}
	93
	94	/* This MUST be done before doing anything irreversible... */
dba32306	95	err = notify_change(filp->f_path.dentry, &ia);
1da177e4 LT	96	if (err)
	97	goto up;
	98
	99	if (sbi->options.sys_immutable) {
	100	if (attr & ATTR_SYS)
	101	inode->i_flags \|= S_IMMUTABLE;
	102	else
	103	inode->i_flags &= S_IMMUTABLE;
	104	}
	105
	106	MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED;
	107	mark_inode_dirty(inode);
	108	up:
1b1dcc1b	109	mutex_unlock(&inode->i_mutex);
1da177e4 LT	110	return err;
	111	}
	112	default:
	113	return -ENOTTY; /* Inappropriate ioctl for device */
	114	}
	115	}
	116
ae78bf9c CM	117	static int fat_file_release(struct inode inode, struct file filp)
	118	{
	119	if ((filp->f_mode & FMODE_WRITE) &&
	120	MSDOS_SB(inode->i_sb)->options.flush) {
	121	fat_flush_inodes(inode->i_sb, inode, NULL);
3fcfab16	122	congestion_wait(WRITE, HZ/10);
ae78bf9c CM	123	}
	124	return 0;
	125	}
	126
4b6f5d20	127	const struct file_operations fat_file_operations = {
1da177e4 LT	128	.llseek = generic_file_llseek,
	129	.read = do_sync_read,
	130	.write = do_sync_write,
1da177e4	131	.aio_read = generic_file_aio_read,
ef402268	132	.aio_write = generic_file_aio_write,
1da177e4	133	.mmap = generic_file_mmap,
ae78bf9c	134	.release = fat_file_release,
1da177e4 LT	135	.ioctl = fat_generic_ioctl,
	136	.fsync = file_fsync,
	137	.sendfile = generic_file_sendfile,
	138	};
	139
05eb0b51 OH	140	static int fat_cont_expand(struct inode *inode, loff_t size)
	141	{
	142	struct address_space *mapping = inode->i_mapping;
	143	loff_t start = inode->i_size, count = size - inode->i_size;
	144	int err;
	145
	146	err = generic_cont_expand_simple(inode, size);
	147	if (err)
	148	goto out;
	149
	150	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
	151	mark_inode_dirty(inode);
	152	if (IS_SYNC(inode))
	153	err = sync_page_range_nolock(inode, mapping, start, count);
	154	out:
	155	return err;
	156	}
	157
1da177e4 LT	158	int fat_notify_change(struct dentry dentry, struct iattr attr)
	159	{
	160	struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
	161	struct inode *inode = dentry->d_inode;
	162	int mask, error = 0;
	163
	164	lock_kernel();
	165
05eb0b51 OH	166	/*
	167	* Expand the file. Since inode_setattr() updates ->i_size
	168	* before calling the ->truncate(), but FAT needs to fill the
	169	* hole before it.
	170	*/
1da177e4 LT	171	if (attr->ia_valid & ATTR_SIZE) {
1da177e4 LT	172	if (attr->ia_size > inode->i_size) {
05eb0b51 OH	173	error = fat_cont_expand(inode, attr->ia_size);
	174	if (error \|\| attr->ia_valid == ATTR_SIZE)
	175	goto out;
	176	attr->ia_valid &= ~ATTR_SIZE;
1da177e4 LT	177	}
	178	}
	179
	180	error = inode_change_ok(inode, attr);
	181	if (error) {
	182	if (sbi->options.quiet)
	183	error = 0;
	184	goto out;
	185	}
	186	if (((attr->ia_valid & ATTR_UID) &&
	187	(attr->ia_uid != sbi->options.fs_uid)) \|\|
	188	((attr->ia_valid & ATTR_GID) &&
	189	(attr->ia_gid != sbi->options.fs_gid)) \|\|
	190	((attr->ia_valid & ATTR_MODE) &&
	191	(attr->ia_mode & ~MSDOS_VALID_MODE)))
	192	error = -EPERM;
	193
	194	if (error) {
	195	if (sbi->options.quiet)
	196	error = 0;
	197	goto out;
	198	}
	199	error = inode_setattr(inode, attr);
	200	if (error)
	201	goto out;
	202
	203	if (S_ISDIR(inode->i_mode))
	204	mask = sbi->options.fs_dmask;
	205	else
	206	mask = sbi->options.fs_fmask;
	207	inode->i_mode &= S_IFMT \| (S_IRWXUGO & ~mask);
	208	out:
	209	unlock_kernel();
	210	return error;
	211	}
	212
7c709d00	213	EXPORT_SYMBOL_GPL(fat_notify_change);
1da177e4 LT	214
	215	/* Free all clusters after the skip'th cluster. */
	216	static int fat_free(struct inode *inode, int skip)
	217	{
	218	struct super_block *sb = inode->i_sb;
	219	int err, wait, free_start, i_start, i_logstart;
	220
	221	if (MSDOS_I(inode)->i_start == 0)
	222	return 0;
	223
3b641407 OH	224	fat_cache_inval_inode(inode);
3b641407 OH	225
1da177e4	226	wait = IS_DIRSYNC(inode);
3b641407 OH	227	i_start = free_start = MSDOS_I(inode)->i_start;
	228	i_logstart = MSDOS_I(inode)->i_logstart;
	229
	230	/* First, we write the new file size. */
	231	if (!skip) {
	232	MSDOS_I(inode)->i_start = 0;
	233	MSDOS_I(inode)->i_logstart = 0;
	234	}
	235	MSDOS_I(inode)->i_attrs \|= ATTR_ARCH;
	236	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
	237	if (wait) {
	238	err = fat_sync_inode(inode);
	239	if (err) {
	240	MSDOS_I(inode)->i_start = i_start;
	241	MSDOS_I(inode)->i_logstart = i_logstart;
	242	return err;
	243	}
	244	} else
	245	mark_inode_dirty(inode);
	246
	247	/* Write a new EOF, and get the remaining cluster chain for freeing. */
1da177e4 LT	248	if (skip) {
	249	struct fat_entry fatent;
	250	int ret, fclus, dclus;
	251
	252	ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
	253	if (ret < 0)
	254	return ret;
	255	else if (ret == FAT_ENT_EOF)
	256	return 0;
	257
	258	fatent_init(&fatent);
	259	ret = fat_ent_read(inode, &fatent, dclus);
	260	if (ret == FAT_ENT_EOF) {
	261	fatent_brelse(&fatent);
	262	return 0;
	263	} else if (ret == FAT_ENT_FREE) {
	264	fat_fs_panic(sb,
	265	"%s: invalid cluster chain (i_pos %lld)",
	266	__FUNCTION__, MSDOS_I(inode)->i_pos);
	267	ret = -EIO;
	268	} else if (ret > 0) {
	269	err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
	270	if (err)
	271	ret = err;
	272	}
	273	fatent_brelse(&fatent);
	274	if (ret < 0)
	275	return ret;
	276
	277	free_start = ret;
1da177e4	278	}
1da177e4 LT	279	inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
	280
	281	/* Freeing the remained cluster chain */
	282	return fat_free_clusters(inode, free_start);
1da177e4 LT	283	}
	284
	285	void fat_truncate(struct inode *inode)
	286	{
	287	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
	288	const unsigned int cluster_size = sbi->cluster_size;
	289	int nr_clusters;
	290
	291	/*
	292	* This protects against truncating a file bigger than it was then
	293	* trying to write into the hole.
	294	*/
	295	if (MSDOS_I(inode)->mmu_private > inode->i_size)
	296	MSDOS_I(inode)->mmu_private = inode->i_size;
	297
	298	nr_clusters = (inode->i_size + (cluster_size - 1)) >> sbi->cluster_bits;
	299
	300	lock_kernel();
	301	fat_free(inode, nr_clusters);
	302	unlock_kernel();
ae78bf9c	303	fat_flush_inodes(inode->i_sb, inode, NULL);
1da177e4 LT	304	}
1da177e4 LT	305
da63fc7c OH	306	int fat_getattr(struct vfsmount mnt, struct dentry dentry, struct kstat *stat)
	307	{
	308	struct inode *inode = dentry->d_inode;
	309	generic_fillattr(inode, stat);
	310	stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
	311	return 0;
	312	}
	313	EXPORT_SYMBOL_GPL(fat_getattr);
	314
754661f1	315	const struct inode_operations fat_file_inode_operations = {
1da177e4 LT	316	.truncate = fat_truncate,
1da177e4 LT	317	.setattr = fat_notify_change,
da63fc7c	318	.getattr = fat_getattr,
1da177e4	319	};