[linux.git] / fs / sync.c

/*
 * High-level sync()-related operations
 */

#include <linux/kernel.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/writeback.h>
#include <linux/syscalls.h>
#include <linux/linkage.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/buffer_head.h>

#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
			SYNC_FILE_RANGE_WAIT_AFTER)

/*
 * sync everything.  Start out by waking pdflush, because that writes back
 * all queues in parallel.
 */
static void do_sync(unsigned long wait)
{
	wakeup_pdflush(0);
	sync_inodes(0);		/* All mappings, inodes and their blockdevs */
	DQUOT_SYNC(NULL);
	sync_supers();		/* Write the superblocks */
	sync_filesystems(0);	/* Start syncing the filesystems */
	sync_filesystems(wait);	/* Waitingly sync the filesystems */
	sync_inodes(wait);	/* Mappings, inodes and blockdevs, again. */
	if (!wait)
		printk("Emergency Sync complete\n");
	if (unlikely(laptop_mode))
		laptop_sync_completion();
}

asmlinkage long sys_sync(void)
{
	do_sync(1);
	return 0;
}

void emergency_sync(void)
{
	pdflush_operation(do_sync, 0);
}

/*
 * Generic function to fsync a file.
 *
 * filp may be NULL if called via the msync of a vma.
 */
int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
{
	struct inode * inode = dentry->d_inode;
	struct super_block * sb;
	int ret, err;

	/* sync the inode to buffers */
	ret = write_inode_now(inode, 0);

	/* sync the superblock to buffers */
	sb = inode->i_sb;
	lock_super(sb);
	if (sb->s_dirt && sb->s_op->write_super)
		sb->s_op->write_super(sb);
	unlock_super(sb);

	/* .. finally sync the buffers to disk */
	err = sync_blockdev(sb->s_bdev);
	if (!ret)
		ret = err;
	return ret;
}

/**
 * vfs_fsync - perform a fsync or fdatasync on a file
 * @file:		file to sync
 * @dentry:		dentry of @file
 * @data:		only perform a fdatasync operation
 *
 * Write back data and metadata for @file to disk.  If @datasync is
 * set only metadata needed to access modified file data is written.
 *
 * In case this function is called from nfsd @file may be %NULL and
 * only @dentry is set.  This can only happen when the filesystem
 * implements the export_operations API.
 */
int vfs_fsync(struct file *file, struct dentry *dentry, int datasync)
{
	const struct file_operations *fop;
	struct address_space *mapping;
	int err, ret;

	/*
	 * Get mapping and operations from the file in case we have
	 * as file, or get the default values for them in case we
	 * don't have a struct file available.  Damn nfsd..
	 */
	if (file) {
		mapping = file->f_mapping;
		fop = file->f_op;
	} else {
		mapping = dentry->d_inode->i_mapping;
		fop = dentry->d_inode->i_fop;
	}

	if (!fop || !fop->fsync) {
		ret = -EINVAL;
		goto out;
	}

	ret = filemap_fdatawrite(mapping);

	/*
	 * We need to protect against concurrent writers, which could cause
	 * livelocks in fsync_buffers_list().
	 */
	mutex_lock(&mapping->host->i_mutex);
	err = fop->fsync(file, dentry, datasync);
	if (!ret)
		ret = err;
	mutex_unlock(&mapping->host->i_mutex);
	err = filemap_fdatawait(mapping);
	if (!ret)
		ret = err;
out:
	return ret;
}
EXPORT_SYMBOL(vfs_fsync);

static int do_fsync(unsigned int fd, int datasync)
{
	struct file *file;
	int ret = -EBADF;

	file = fget(fd);
	if (file) {
		ret = vfs_fsync(file, file->f_path.dentry, datasync);
		fput(file);
	}
	return ret;
}

asmlinkage long sys_fsync(unsigned int fd)
{
	return do_fsync(fd, 0);
}

asmlinkage long sys_fdatasync(unsigned int fd)
{
	return do_fsync(fd, 1);
}

/*
 * sys_sync_file_range() permits finely controlled syncing over a segment of
 * a file in the range offset .. (offset+nbytes-1) inclusive.  If nbytes is
 * zero then sys_sync_file_range() will operate from offset out to EOF.
 *
 * The flag bits are:
 *
 * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
 * before performing the write.
 *
 * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
 * range which are not presently under writeback. Note that this may block for
 * significant periods due to exhaustion of disk request structures.
 *
 * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
 * after performing the write.
 *
 * Useful combinations of the flag bits are:
 *
 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
 * in the range which were dirty on entry to sys_sync_file_range() are placed
 * under writeout.  This is a start-write-for-data-integrity operation.
 *
 * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
 * are not presently under writeout.  This is an asynchronous flush-to-disk
 * operation.  Not suitable for data integrity operations.
 *
 * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
 * completion of writeout of all pages in the range.  This will be used after an
 * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
 * for that operation to complete and to return the result.
 *
 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
 * a traditional sync() operation.  This is a write-for-data-integrity operation
 * which will ensure that all pages in the range which were dirty on entry to
 * sys_sync_file_range() are committed to disk.
 *
 *
 * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
 * I/O errors or ENOSPC conditions and will return those to the caller, after
 * clearing the EIO and ENOSPC flags in the address_space.
 *
 * It should be noted that none of these operations write out the file's
 * metadata.  So unless the application is strictly performing overwrites of
 * already-instantiated disk blocks, there are no guarantees here that the data
 * will be available after a crash.
 */
SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
				unsigned int flags)
{
	int ret;
	struct file *file;
	loff_t endbyte;			/* inclusive */
	int fput_needed;
	umode_t i_mode;

	ret = -EINVAL;
	if (flags & ~VALID_FLAGS)
		goto out;

	endbyte = offset + nbytes;

	if ((s64)offset < 0)
		goto out;
	if ((s64)endbyte < 0)
		goto out;
	if (endbyte < offset)
		goto out;

	if (sizeof(pgoff_t) == 4) {
		if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
			/*
			 * The range starts outside a 32 bit machine's
			 * pagecache addressing capabilities.  Let it "succeed"
			 */
			ret = 0;
			goto out;
		}
		if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
			/*
			 * Out to EOF
			 */
			nbytes = 0;
		}
	}

	if (nbytes == 0)
		endbyte = LLONG_MAX;
	else
		endbyte--;		/* inclusive */

	ret = -EBADF;
	file = fget_light(fd, &fput_needed);
	if (!file)
		goto out;

	i_mode = file->f_path.dentry->d_inode->i_mode;
	ret = -ESPIPE;
	if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
			!S_ISLNK(i_mode))
		goto out_put;

	ret = do_sync_mapping_range(file->f_mapping, offset, endbyte, flags);
out_put:
	fput_light(file, fput_needed);
out:
	return ret;
}
#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
asmlinkage long SyS_sync_file_range(long fd, loff_t offset, loff_t nbytes,
				    long flags)
{
	return SYSC_sync_file_range((int) fd, offset, nbytes,
				    (unsigned int) flags);
}
SYSCALL_ALIAS(sys_sync_file_range, SyS_sync_file_range);
#endif

/* It would be nice if people remember that not all the world's an i386
   when they introduce new system calls */
SYSCALL_DEFINE(sync_file_range2)(int fd, unsigned int flags,
				 loff_t offset, loff_t nbytes)
{
	return sys_sync_file_range(fd, offset, nbytes, flags);
}
#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
asmlinkage long SyS_sync_file_range2(long fd, long flags,
				     loff_t offset, loff_t nbytes)
{
	return SYSC_sync_file_range2((int) fd, (unsigned int) flags,
				     offset, nbytes);
}
SYSCALL_ALIAS(sys_sync_file_range2, SyS_sync_file_range2);
#endif

/*
 * `endbyte' is inclusive
 */
int do_sync_mapping_range(struct address_space *mapping, loff_t offset,
			  loff_t endbyte, unsigned int flags)
{
	int ret;

	if (!mapping) {
		ret = -EINVAL;
		goto out;
	}

	ret = 0;
	if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
		ret = wait_on_page_writeback_range(mapping,
					offset >> PAGE_CACHE_SHIFT,
					endbyte >> PAGE_CACHE_SHIFT);
		if (ret < 0)
			goto out;
	}

	if (flags & SYNC_FILE_RANGE_WRITE) {
		ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
						WB_SYNC_ALL);
		if (ret < 0)
			goto out;
	}

	if (flags & SYNC_FILE_RANGE_WAIT_AFTER) {
		ret = wait_on_page_writeback_range(mapping,
					offset >> PAGE_CACHE_SHIFT,
					endbyte >> PAGE_CACHE_SHIFT);
	}
out:
	return ret;
}
EXPORT_SYMBOL_GPL(do_sync_mapping_range);
Commit	Line	Data
f79e2abb AM	1	/*
	2	* High-level sync()-related operations
	3	*/
	4
	5	#include <linux/kernel.h>
	6	#include <linux/file.h>
	7	#include <linux/fs.h>
	8	#include <linux/module.h>
914e2637	9	#include <linux/sched.h>
f79e2abb AM	10	#include <linux/writeback.h>
	11	#include <linux/syscalls.h>
	12	#include <linux/linkage.h>
	13	#include <linux/pagemap.h>
cf9a2ae8 DH	14	#include <linux/quotaops.h>
cf9a2ae8 DH	15	#include <linux/buffer_head.h>
f79e2abb AM	16
	17	#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE\|SYNC_FILE_RANGE_WRITE\| \
	18	SYNC_FILE_RANGE_WAIT_AFTER)
	19
cf9a2ae8 DH	20	/*
	21	* sync everything. Start out by waking pdflush, because that writes back
	22	* all queues in parallel.
	23	*/
	24	static void do_sync(unsigned long wait)
	25	{
	26	wakeup_pdflush(0);
	27	sync_inodes(0); /* All mappings, inodes and their blockdevs */
	28	DQUOT_SYNC(NULL);
	29	sync_supers(); /* Write the superblocks */
	30	sync_filesystems(0); /* Start syncing the filesystems */
	31	sync_filesystems(wait); /* Waitingly sync the filesystems */
	32	sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
	33	if (!wait)
	34	printk("Emergency Sync complete\n");
	35	if (unlikely(laptop_mode))
	36	laptop_sync_completion();
	37	}
	38
	39	asmlinkage long sys_sync(void)
	40	{
	41	do_sync(1);
	42	return 0;
	43	}
	44
	45	void emergency_sync(void)
	46	{
	47	pdflush_operation(do_sync, 0);
	48	}
	49
	50	/*
	51	* Generic function to fsync a file.
	52	*
	53	* filp may be NULL if called via the msync of a vma.
	54	*/
	55	int file_fsync(struct file filp, struct dentry dentry, int datasync)
	56	{
	57	struct inode * inode = dentry->d_inode;
	58	struct super_block * sb;
	59	int ret, err;
	60
	61	/* sync the inode to buffers */
	62	ret = write_inode_now(inode, 0);
	63
	64	/* sync the superblock to buffers */
	65	sb = inode->i_sb;
	66	lock_super(sb);
762873c2	67	if (sb->s_dirt && sb->s_op->write_super)
cf9a2ae8 DH	68	sb->s_op->write_super(sb);
	69	unlock_super(sb);
	70
	71	/* .. finally sync the buffers to disk */
	72	err = sync_blockdev(sb->s_bdev);
	73	if (!ret)
	74	ret = err;
	75	return ret;
	76	}
	77
4c728ef5 CH	78	/**
	79	* vfs_fsync - perform a fsync or fdatasync on a file
	80	* @file: file to sync
	81	* @dentry: dentry of @file
	82	* @data: only perform a fdatasync operation
	83	*
	84	* Write back data and metadata for @file to disk. If @datasync is
	85	* set only metadata needed to access modified file data is written.
	86	*
	87	* In case this function is called from nfsd @file may be %NULL and
	88	* only @dentry is set. This can only happen when the filesystem
	89	* implements the export_operations API.
	90	*/
	91	int vfs_fsync(struct file file, struct dentry dentry, int datasync)
cf9a2ae8	92	{
4c728ef5 CH	93	const struct file_operations *fop;
	94	struct address_space *mapping;
	95	int err, ret;
	96
	97	/*
	98	* Get mapping and operations from the file in case we have
	99	* as file, or get the default values for them in case we
	100	* don't have a struct file available. Damn nfsd..
	101	*/
	102	if (file) {
	103	mapping = file->f_mapping;
	104	fop = file->f_op;
	105	} else {
	106	mapping = dentry->d_inode->i_mapping;
	107	fop = dentry->d_inode->i_fop;
	108	}
cf9a2ae8	109
4c728ef5	110	if (!fop \|\| !fop->fsync) {
cf9a2ae8 DH	111	ret = -EINVAL;
	112	goto out;
	113	}
	114
	115	ret = filemap_fdatawrite(mapping);
	116
	117	/*
	118	* We need to protect against concurrent writers, which could cause
	119	* livelocks in fsync_buffers_list().
	120	*/
	121	mutex_lock(&mapping->host->i_mutex);
4c728ef5	122	err = fop->fsync(file, dentry, datasync);
cf9a2ae8 DH	123	if (!ret)
	124	ret = err;
	125	mutex_unlock(&mapping->host->i_mutex);
	126	err = filemap_fdatawait(mapping);
	127	if (!ret)
	128	ret = err;
	129	out:
	130	return ret;
	131	}
4c728ef5	132	EXPORT_SYMBOL(vfs_fsync);
cf9a2ae8	133
4c728ef5	134	static int do_fsync(unsigned int fd, int datasync)
cf9a2ae8 DH	135	{
	136	struct file *file;
	137	int ret = -EBADF;
	138
	139	file = fget(fd);
	140	if (file) {
4c728ef5	141	ret = vfs_fsync(file, file->f_path.dentry, datasync);
cf9a2ae8 DH	142	fput(file);
	143	}
	144	return ret;
	145	}
	146
	147	asmlinkage long sys_fsync(unsigned int fd)
	148	{
4c728ef5	149	return do_fsync(fd, 0);
cf9a2ae8 DH	150	}
	151
	152	asmlinkage long sys_fdatasync(unsigned int fd)
	153	{
4c728ef5	154	return do_fsync(fd, 1);
cf9a2ae8 DH	155	}
cf9a2ae8 DH	156
f79e2abb AM	157	/*
	158	* sys_sync_file_range() permits finely controlled syncing over a segment of
	159	* a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
	160	* zero then sys_sync_file_range() will operate from offset out to EOF.
	161	*
	162	* The flag bits are:
	163	*
	164	* SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
	165	* before performing the write.
	166	*
	167	* SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
cce77081 PM	168	* range which are not presently under writeback. Note that this may block for
cce77081 PM	169	* significant periods due to exhaustion of disk request structures.
f79e2abb AM	170	*
	171	* SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
	172	* after performing the write.
	173	*
	174	* Useful combinations of the flag bits are:
	175	*
	176	* SYNC_FILE_RANGE_WAIT_BEFORE\|SYNC_FILE_RANGE_WRITE: ensures that all pages
	177	* in the range which were dirty on entry to sys_sync_file_range() are placed
	178	* under writeout. This is a start-write-for-data-integrity operation.
	179	*
	180	* SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
	181	* are not presently under writeout. This is an asynchronous flush-to-disk
	182	* operation. Not suitable for data integrity operations.
	183	*
	184	* SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
	185	* completion of writeout of all pages in the range. This will be used after an
	186	* earlier SYNC_FILE_RANGE_WAIT_BEFORE\|SYNC_FILE_RANGE_WRITE operation to wait
	187	* for that operation to complete and to return the result.
	188	*
	189	* SYNC_FILE_RANGE_WAIT_BEFORE\|SYNC_FILE_RANGE_WRITE\|SYNC_FILE_RANGE_WAIT_AFTER:
	190	* a traditional sync() operation. This is a write-for-data-integrity operation
	191	* which will ensure that all pages in the range which were dirty on entry to
	192	* sys_sync_file_range() are committed to disk.
	193	*
	194	*
	195	* SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
	196	* I/O errors or ENOSPC conditions and will return those to the caller, after
	197	* clearing the EIO and ENOSPC flags in the address_space.
	198	*
	199	* It should be noted that none of these operations write out the file's
	200	* metadata. So unless the application is strictly performing overwrites of
	201	* already-instantiated disk blocks, there are no guarantees here that the data
	202	* will be available after a crash.
	203	*/
6673e0c3 HC	204	SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
6673e0c3 HC	205	unsigned int flags)
f79e2abb AM	206	{
	207	int ret;
	208	struct file *file;
	209	loff_t endbyte; /* inclusive */
	210	int fput_needed;
	211	umode_t i_mode;
	212
	213	ret = -EINVAL;
	214	if (flags & ~VALID_FLAGS)
	215	goto out;
	216
	217	endbyte = offset + nbytes;
	218
	219	if ((s64)offset < 0)
	220	goto out;
	221	if ((s64)endbyte < 0)
	222	goto out;
	223	if (endbyte < offset)
	224	goto out;
	225
	226	if (sizeof(pgoff_t) == 4) {
	227	if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
	228	/*
	229	* The range starts outside a 32 bit machine's
	230	* pagecache addressing capabilities. Let it "succeed"
	231	*/
	232	ret = 0;
	233	goto out;
	234	}
	235	if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
	236	/*
	237	* Out to EOF
	238	*/
	239	nbytes = 0;
	240	}
	241	}
	242
	243	if (nbytes == 0)
111ebb6e	244	endbyte = LLONG_MAX;
f79e2abb AM	245	else
	246	endbyte--; /* inclusive */
	247
	248	ret = -EBADF;
	249	file = fget_light(fd, &fput_needed);
	250	if (!file)
	251	goto out;
	252
0f7fc9e4	253	i_mode = file->f_path.dentry->d_inode->i_mode;
f79e2abb AM	254	ret = -ESPIPE;
	255	if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
	256	!S_ISLNK(i_mode))
	257	goto out_put;
	258
ef51c976	259	ret = do_sync_mapping_range(file->f_mapping, offset, endbyte, flags);
f79e2abb AM	260	out_put:
	261	fput_light(file, fput_needed);
	262	out:
	263	return ret;
	264	}
6673e0c3 HC	265	#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
	266	asmlinkage long SyS_sync_file_range(long fd, loff_t offset, loff_t nbytes,
	267	long flags)
	268	{
	269	return SYSC_sync_file_range((int) fd, offset, nbytes,
	270	(unsigned int) flags);
	271	}
	272	SYSCALL_ALIAS(sys_sync_file_range, SyS_sync_file_range);
	273	#endif
f79e2abb	274
edd5cd4a DW	275	/* It would be nice if people remember that not all the world's an i386
edd5cd4a DW	276	when they introduce new system calls */
6673e0c3 HC	277	SYSCALL_DEFINE(sync_file_range2)(int fd, unsigned int flags,
6673e0c3 HC	278	loff_t offset, loff_t nbytes)
edd5cd4a DW	279	{
	280	return sys_sync_file_range(fd, offset, nbytes, flags);
	281	}
6673e0c3 HC	282	#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
	283	asmlinkage long SyS_sync_file_range2(long fd, long flags,
	284	loff_t offset, loff_t nbytes)
	285	{
	286	return SYSC_sync_file_range2((int) fd, (unsigned int) flags,
	287	offset, nbytes);
	288	}
	289	SYSCALL_ALIAS(sys_sync_file_range2, SyS_sync_file_range2);
	290	#endif
edd5cd4a	291
f79e2abb AM	292	/*
	293	* `endbyte' is inclusive
	294	*/
5b04aa3a MF	295	int do_sync_mapping_range(struct address_space *mapping, loff_t offset,
5b04aa3a MF	296	loff_t endbyte, unsigned int flags)
f79e2abb AM	297	{
f79e2abb AM	298	int ret;
f79e2abb	299
f79e2abb AM	300	if (!mapping) {
	301	ret = -EINVAL;
	302	goto out;
	303	}
	304
	305	ret = 0;
	306	if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
	307	ret = wait_on_page_writeback_range(mapping,
	308	offset >> PAGE_CACHE_SHIFT,
	309	endbyte >> PAGE_CACHE_SHIFT);
	310	if (ret < 0)
	311	goto out;
	312	}
	313
	314	if (flags & SYNC_FILE_RANGE_WRITE) {
	315	ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
ee53a891	316	WB_SYNC_ALL);
f79e2abb AM	317	if (ret < 0)
	318	goto out;
	319	}
	320
	321	if (flags & SYNC_FILE_RANGE_WAIT_AFTER) {
	322	ret = wait_on_page_writeback_range(mapping,
	323	offset >> PAGE_CACHE_SHIFT,
	324	endbyte >> PAGE_CACHE_SHIFT);
	325	}
	326	out:
	327	return ret;
	328	}
5b04aa3a	329	EXPORT_SYMBOL_GPL(do_sync_mapping_range);