[linux.git] / fs / xfs / xfs_pnfs.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2014 Christoph Hellwig.
 */
#include <linux/iomap.h>
#include "xfs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_log.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_error.h"
#include "xfs_iomap.h"
#include "xfs_shared.h"
#include "xfs_bit.h"
#include "xfs_pnfs.h"

/*
 * Ensure that we do not have any outstanding pNFS layouts that can be used by
 * clients to directly read from or write to this inode.  This must be called
 * before every operation that can remove blocks from the extent map.
 * Additionally we call it during the write operation, where aren't concerned
 * about exposing unallocated blocks but just want to provide basic
 * synchronization between a local writer and pNFS clients.  mmap writes would
 * also benefit from this sort of synchronization, but due to the tricky locking
 * rules in the page fault path we don't bother.
 */
int
xfs_break_leased_layouts(
	struct inode		*inode,
	uint			*iolock,
	bool			*did_unlock)
{
	struct xfs_inode	*ip = XFS_I(inode);
	int			error;

	while ((error = break_layout(inode, false) == -EWOULDBLOCK)) {
		xfs_iunlock(ip, *iolock);
		*did_unlock = true;
		error = break_layout(inode, true);
		*iolock &= ~XFS_IOLOCK_SHARED;
		*iolock |= XFS_IOLOCK_EXCL;
		xfs_ilock(ip, *iolock);
	}

	return error;
}

/*
 * Get a unique ID including its location so that the client can identify
 * the exported device.
 */
int
xfs_fs_get_uuid(
	struct super_block	*sb,
	u8			*buf,
	u32			*len,
	u64			*offset)
{
	struct xfs_mount	*mp = XFS_M(sb);

	printk_once(KERN_NOTICE
"XFS (%s): using experimental pNFS feature, use at your own risk!\n",
		mp->m_fsname);

	if (*len < sizeof(uuid_t))
		return -EINVAL;

	memcpy(buf, &mp->m_sb.sb_uuid, sizeof(uuid_t));
	*len = sizeof(uuid_t);
	*offset = offsetof(struct xfs_dsb, sb_uuid);
	return 0;
}

/*
 * Get a layout for the pNFS client.
 */
int
xfs_fs_map_blocks(
	struct inode		*inode,
	loff_t			offset,
	u64			length,
	struct iomap		*iomap,
	bool			write,
	u32			*device_generation)
{
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	struct xfs_bmbt_irec	imap;
	xfs_fileoff_t		offset_fsb, end_fsb;
	loff_t			limit;
	int			bmapi_flags = XFS_BMAPI_ENTIRE;
	int			nimaps = 1;
	uint			lock_flags;
	int			error = 0;

	if (XFS_FORCED_SHUTDOWN(mp))
		return -EIO;

	/*
	 * We can't export inodes residing on the realtime device.  The realtime
	 * device doesn't have a UUID to identify it, so the client has no way
	 * to find it.
	 */
	if (XFS_IS_REALTIME_INODE(ip))
		return -ENXIO;

	/*
	 * The pNFS block layout spec actually supports reflink like
	 * functionality, but the Linux pNFS server doesn't implement it yet.
	 */
	if (xfs_is_reflink_inode(ip))
		return -ENXIO;

	/*
	 * Lock out any other I/O before we flush and invalidate the pagecache,
	 * and then hand out a layout to the remote system.  This is very
	 * similar to direct I/O, except that the synchronization is much more
	 * complicated.  See the comment near xfs_break_leased_layouts
	 * for a detailed explanation.
	 */
	xfs_ilock(ip, XFS_IOLOCK_EXCL);

	error = -EINVAL;
	limit = mp->m_super->s_maxbytes;
	if (!write)
		limit = max(limit, round_up(i_size_read(inode),
				     inode->i_sb->s_blocksize));
	if (offset > limit)
		goto out_unlock;
	if (offset > limit - length)
		length = limit - offset;

	error = filemap_write_and_wait(inode->i_mapping);
	if (error)
		goto out_unlock;
	error = invalidate_inode_pages2(inode->i_mapping);
	if (WARN_ON_ONCE(error))
		return error;

	end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + length);
	offset_fsb = XFS_B_TO_FSBT(mp, offset);

	lock_flags = xfs_ilock_data_map_shared(ip);
	error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
				&imap, &nimaps, bmapi_flags);
	xfs_iunlock(ip, lock_flags);

	if (error)
		goto out_unlock;

	if (write) {
		enum xfs_prealloc_flags	flags = 0;

		ASSERT(imap.br_startblock != DELAYSTARTBLOCK);

		if (!nimaps || imap.br_startblock == HOLESTARTBLOCK) {
			/*
			 * xfs_iomap_write_direct() expects to take ownership of
			 * the shared ilock.
			 */
			xfs_ilock(ip, XFS_ILOCK_SHARED);
			error = xfs_iomap_write_direct(ip, offset, length,
						       &imap, nimaps);
			if (error)
				goto out_unlock;

			/*
			 * Ensure the next transaction is committed
			 * synchronously so that the blocks allocated and
			 * handed out to the client are guaranteed to be
			 * present even after a server crash.
			 */
			flags |= XFS_PREALLOC_SET | XFS_PREALLOC_SYNC;
		}

		error = xfs_update_prealloc_flags(ip, flags);
		if (error)
			goto out_unlock;
	}
	xfs_iunlock(ip, XFS_IOLOCK_EXCL);

	error = xfs_bmbt_to_iomap(ip, iomap, &imap, false);
	*device_generation = mp->m_generation;
	return error;
out_unlock:
	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
	return error;
}

/*
 * Ensure the size update falls into a valid allocated block.
 */
static int
xfs_pnfs_validate_isize(
	struct xfs_inode	*ip,
	xfs_off_t		isize)
{
	struct xfs_bmbt_irec	imap;
	int			nimaps = 1;
	int			error = 0;

	xfs_ilock(ip, XFS_ILOCK_SHARED);
	error = xfs_bmapi_read(ip, XFS_B_TO_FSBT(ip->i_mount, isize - 1), 1,
				&imap, &nimaps, 0);
	xfs_iunlock(ip, XFS_ILOCK_SHARED);
	if (error)
		return error;

	if (imap.br_startblock == HOLESTARTBLOCK ||
	    imap.br_startblock == DELAYSTARTBLOCK ||
	    imap.br_state == XFS_EXT_UNWRITTEN)
		return -EIO;
	return 0;
}

/*
 * Make sure the blocks described by maps are stable on disk.  This includes
 * converting any unwritten extents, flushing the disk cache and updating the
 * time stamps.
 *
 * Note that we rely on the caller to always send us a timestamp update so that
 * we always commit a transaction here.  If that stops being true we will have
 * to manually flush the cache here similar to what the fsync code path does
 * for datasyncs on files that have no dirty metadata.
 */
int
xfs_fs_commit_blocks(
	struct inode		*inode,
	struct iomap		*maps,
	int			nr_maps,
	struct iattr		*iattr)
{
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	struct xfs_trans	*tp;
	bool			update_isize = false;
	int			error, i;
	loff_t			size;

	ASSERT(iattr->ia_valid & (ATTR_ATIME|ATTR_CTIME|ATTR_MTIME));

	xfs_ilock(ip, XFS_IOLOCK_EXCL);

	size = i_size_read(inode);
	if ((iattr->ia_valid & ATTR_SIZE) && iattr->ia_size > size) {
		update_isize = true;
		size = iattr->ia_size;
	}

	for (i = 0; i < nr_maps; i++) {
		u64 start, length, end;

		start = maps[i].offset;
		if (start > size)
			continue;

		end = start + maps[i].length;
		if (end > size)
			end = size;

		length = end - start;
		if (!length)
			continue;
	
		/*
		 * Make sure reads through the pagecache see the new data.
		 */
		error = invalidate_inode_pages2_range(inode->i_mapping,
					start >> PAGE_SHIFT,
					(end - 1) >> PAGE_SHIFT);
		WARN_ON_ONCE(error);

		error = xfs_iomap_write_unwritten(ip, start, length, false);
		if (error)
			goto out_drop_iolock;
	}

	if (update_isize) {
		error = xfs_pnfs_validate_isize(ip, size);
		if (error)
			goto out_drop_iolock;
	}

	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
	if (error)
		goto out_drop_iolock;

	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

	xfs_setattr_time(ip, iattr);
	if (update_isize) {
		i_size_write(inode, iattr->ia_size);
		ip->i_d.di_size = iattr->ia_size;
	}

	xfs_trans_set_sync(tp);
	error = xfs_trans_commit(tp);

out_drop_iolock:
	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
	return error;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
52785112 CH	2	/*
	3	* Copyright (c) 2014 Christoph Hellwig.
	4	*/
199a31c6	5	#include <linux/iomap.h>
52785112 CH	6	#include "xfs.h"
	7	#include "xfs_format.h"
	8	#include "xfs_log_format.h"
	9	#include "xfs_trans_resv.h"
	10	#include "xfs_sb.h"
	11	#include "xfs_mount.h"
	12	#include "xfs_inode.h"
	13	#include "xfs_trans.h"
	14	#include "xfs_log.h"
	15	#include "xfs_bmap.h"
	16	#include "xfs_bmap_util.h"
	17	#include "xfs_error.h"
	18	#include "xfs_iomap.h"
	19	#include "xfs_shared.h"
	20	#include "xfs_bit.h"
	21	#include "xfs_pnfs.h"
	22
781355c6 CH	23	/*
	24	* Ensure that we do not have any outstanding pNFS layouts that can be used by
	25	* clients to directly read from or write to this inode. This must be called
	26	* before every operation that can remove blocks from the extent map.
	27	* Additionally we call it during the write operation, where aren't concerned
	28	* about exposing unallocated blocks but just want to provide basic
	29	* synchronization between a local writer and pNFS clients. mmap writes would
	30	* also benefit from this sort of synchronization, but due to the tricky locking
	31	* rules in the page fault path we don't bother.
	32	*/
	33	int
69eb5fa1	34	xfs_break_leased_layouts(
781355c6	35	struct inode *inode,
69eb5fa1 DW	36	uint *iolock,
69eb5fa1 DW	37	bool *did_unlock)
781355c6 CH	38	{
	39	struct xfs_inode *ip = XFS_I(inode);
	40	int error;
	41
781355c6 CH	42	while ((error = break_layout(inode, false) == -EWOULDBLOCK)) {
781355c6 CH	43	xfs_iunlock(ip, *iolock);
69eb5fa1	44	*did_unlock = true;
781355c6	45	error = break_layout(inode, true);
c63a8eae DW	46	*iolock &= ~XFS_IOLOCK_SHARED;
c63a8eae DW	47	*iolock \|= XFS_IOLOCK_EXCL;
781355c6 CH	48	xfs_ilock(ip, *iolock);
	49	}
	50
	51	return error;
	52	}
	53
52785112 CH	54	/*
	55	* Get a unique ID including its location so that the client can identify
	56	* the exported device.
	57	*/
	58	int
	59	xfs_fs_get_uuid(
	60	struct super_block *sb,
	61	u8 *buf,
	62	u32 *len,
	63	u64 *offset)
	64	{
	65	struct xfs_mount *mp = XFS_M(sb);
	66
	67	printk_once(KERN_NOTICE
	68	"XFS (%s): using experimental pNFS feature, use at your own risk!\n",
	69	mp->m_fsname);
	70
	71	if (*len < sizeof(uuid_t))
	72	return -EINVAL;
	73
	74	memcpy(buf, &mp->m_sb.sb_uuid, sizeof(uuid_t));
	75	*len = sizeof(uuid_t);
	76	*offset = offsetof(struct xfs_dsb, sb_uuid);
	77	return 0;
	78	}
	79
52785112 CH	80	/*
	81	* Get a layout for the pNFS client.
	82	*/
	83	int
	84	xfs_fs_map_blocks(
	85	struct inode *inode,
	86	loff_t offset,
	87	u64 length,
	88	struct iomap *iomap,
	89	bool write,
	90	u32 *device_generation)
	91	{
	92	struct xfs_inode *ip = XFS_I(inode);
	93	struct xfs_mount *mp = ip->i_mount;
	94	struct xfs_bmbt_irec imap;
	95	xfs_fileoff_t offset_fsb, end_fsb;
	96	loff_t limit;
	97	int bmapi_flags = XFS_BMAPI_ENTIRE;
	98	int nimaps = 1;
	99	uint lock_flags;
	100	int error = 0;
	101
	102	if (XFS_FORCED_SHUTDOWN(mp))
	103	return -EIO;
	104
	105	/*
	106	* We can't export inodes residing on the realtime device. The realtime
	107	* device doesn't have a UUID to identify it, so the client has no way
	108	* to find it.
	109	*/
	110	if (XFS_IS_REALTIME_INODE(ip))
	111	return -ENXIO;
	112
46eeb521 DW	113	/*
	114	* The pNFS block layout spec actually supports reflink like
	115	* functionality, but the Linux pNFS server doesn't implement it yet.
	116	*/
	117	if (xfs_is_reflink_inode(ip))
	118	return -ENXIO;
	119
52785112 CH	120	/*
	121	* Lock out any other I/O before we flush and invalidate the pagecache,
	122	* and then hand out a layout to the remote system. This is very
	123	* similar to direct I/O, except that the synchronization is much more
69eb5fa1 DW	124	* complicated. See the comment near xfs_break_leased_layouts
69eb5fa1 DW	125	* for a detailed explanation.
52785112 CH	126	*/
	127	xfs_ilock(ip, XFS_IOLOCK_EXCL);
	128
	129	error = -EINVAL;
	130	limit = mp->m_super->s_maxbytes;
	131	if (!write)
	132	limit = max(limit, round_up(i_size_read(inode),
	133	inode->i_sb->s_blocksize));
	134	if (offset > limit)
	135	goto out_unlock;
	136	if (offset > limit - length)
	137	length = limit - offset;
	138
	139	error = filemap_write_and_wait(inode->i_mapping);
	140	if (error)
	141	goto out_unlock;
	142	error = invalidate_inode_pages2(inode->i_mapping);
	143	if (WARN_ON_ONCE(error))
	144	return error;
	145
	146	end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + length);
	147	offset_fsb = XFS_B_TO_FSBT(mp, offset);
	148
	149	lock_flags = xfs_ilock_data_map_shared(ip);
	150	error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
	151	&imap, &nimaps, bmapi_flags);
	152	xfs_iunlock(ip, lock_flags);
	153
	154	if (error)
	155	goto out_unlock;
	156
	157	if (write) {
	158	enum xfs_prealloc_flags flags = 0;
	159
	160	ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
	161
	162	if (!nimaps \|\| imap.br_startblock == HOLESTARTBLOCK) {
009c6e87 BF	163	/*
	164	* xfs_iomap_write_direct() expects to take ownership of
	165	* the shared ilock.
	166	*/
	167	xfs_ilock(ip, XFS_ILOCK_SHARED);
52785112 CH	168	error = xfs_iomap_write_direct(ip, offset, length,
	169	&imap, nimaps);
	170	if (error)
	171	goto out_unlock;
	172
	173	/*
	174	* Ensure the next transaction is committed
	175	* synchronously so that the blocks allocated and
	176	* handed out to the client are guaranteed to be
	177	* present even after a server crash.
	178	*/
	179	flags \|= XFS_PREALLOC_SET \| XFS_PREALLOC_SYNC;
	180	}
	181
	182	error = xfs_update_prealloc_flags(ip, flags);
	183	if (error)
	184	goto out_unlock;
	185	}
	186	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
	187
16be1433	188	error = xfs_bmbt_to_iomap(ip, iomap, &imap, false);
52785112 CH	189	*device_generation = mp->m_generation;
	190	return error;
	191	out_unlock:
	192	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
	193	return error;
	194	}
	195
	196	/*
	197	* Ensure the size update falls into a valid allocated block.
	198	*/
	199	static int
	200	xfs_pnfs_validate_isize(
	201	struct xfs_inode *ip,
	202	xfs_off_t isize)
	203	{
	204	struct xfs_bmbt_irec imap;
	205	int nimaps = 1;
	206	int error = 0;
	207
	208	xfs_ilock(ip, XFS_ILOCK_SHARED);
	209	error = xfs_bmapi_read(ip, XFS_B_TO_FSBT(ip->i_mount, isize - 1), 1,
	210	&imap, &nimaps, 0);
	211	xfs_iunlock(ip, XFS_ILOCK_SHARED);
	212	if (error)
	213	return error;
	214
	215	if (imap.br_startblock == HOLESTARTBLOCK \|\|
	216	imap.br_startblock == DELAYSTARTBLOCK \|\|
	217	imap.br_state == XFS_EXT_UNWRITTEN)
	218	return -EIO;
	219	return 0;
	220	}
	221
	222	/*
	223	* Make sure the blocks described by maps are stable on disk. This includes
	224	* converting any unwritten extents, flushing the disk cache and updating the
	225	* time stamps.
	226	*
	227	* Note that we rely on the caller to always send us a timestamp update so that
	228	* we always commit a transaction here. If that stops being true we will have
	229	* to manually flush the cache here similar to what the fsync code path does
	230	* for datasyncs on files that have no dirty metadata.
	231	*/
	232	int
	233	xfs_fs_commit_blocks(
	234	struct inode *inode,
	235	struct iomap *maps,
	236	int nr_maps,
	237	struct iattr *iattr)
	238	{
	239	struct xfs_inode *ip = XFS_I(inode);
	240	struct xfs_mount *mp = ip->i_mount;
	241	struct xfs_trans *tp;
	242	bool update_isize = false;
	243	int error, i;
	244	loff_t size;
	245
	246	ASSERT(iattr->ia_valid & (ATTR_ATIME\|ATTR_CTIME\|ATTR_MTIME));
	247
	248	xfs_ilock(ip, XFS_IOLOCK_EXCL);
	249
	250	size = i_size_read(inode);
	251	if ((iattr->ia_valid & ATTR_SIZE) && iattr->ia_size > size) {
	252	update_isize = true;
253	size = iattr->ia_size;
254	}
255
256	for (i = 0; i < nr_maps; i++) {
257	u64 start, length, end;
258
259	start = maps[i].offset;
260	if (start > size)
261	continue;
262
263	end = start + maps[i].length;
264	if (end > size)
265	end = size;
266
267	length = end - start;
268	if (!length)
269	continue;
270
271	/*
272	* Make sure reads through the pagecache see the new data.
273	*/
274	error = invalidate_inode_pages2_range(inode->i_mapping,
09cbfeaf KS	275	start >> PAGE_SHIFT,
09cbfeaf KS	276	(end - 1) >> PAGE_SHIFT);
52785112 CH	277	WARN_ON_ONCE(error);
52785112 CH	278
ee70daab	279	error = xfs_iomap_write_unwritten(ip, start, length, false);
52785112 CH	280	if (error)
	281	goto out_drop_iolock;
	282	}
	283
	284	if (update_isize) {
	285	error = xfs_pnfs_validate_isize(ip, size);
	286	if (error)
	287	goto out_drop_iolock;
	288	}
	289
253f4911 CH	290	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
253f4911 CH	291	if (error)
52785112 CH	292	goto out_drop_iolock;
	293
	294	xfs_ilock(ip, XFS_ILOCK_EXCL);
	295	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
	296	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	297
	298	xfs_setattr_time(ip, iattr);
	299	if (update_isize) {
	300	i_size_write(inode, iattr->ia_size);
	301	ip->i_d.di_size = iattr->ia_size;
	302	}
	303
	304	xfs_trans_set_sync(tp);
70393313	305	error = xfs_trans_commit(tp);
52785112 CH	306
	307	out_drop_iolock:
	308	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
	309	return error;
	310	}