xfs_file.c 40.3 KB
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/*
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 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
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 *
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 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
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 * published by the Free Software Foundation.
 *
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 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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 */
#include "xfs.h"
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#include "xfs_fs.h"
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#include "xfs_shared.h"
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#include "xfs_format.h"
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#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
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#include "xfs_mount.h"
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#include "xfs_da_format.h"
#include "xfs_da_btree.h"
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#include "xfs_inode.h"
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#include "xfs_trans.h"
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#include "xfs_inode_item.h"
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#include "xfs_bmap.h"
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#include "xfs_bmap_util.h"
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#include "xfs_error.h"
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#include "xfs_dir2.h"
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#include "xfs_dir2_priv.h"
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#include "xfs_ioctl.h"
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#include "xfs_trace.h"
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#include "xfs_log.h"
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#include "xfs_icache.h"
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#include "xfs_pnfs.h"
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#include "xfs_iomap.h"
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#include "xfs_reflink.h"
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#include <linux/dcache.h>
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#include <linux/falloc.h>
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#include <linux/pagevec.h>
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#include <linux/backing-dev.h>
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static const struct vm_operations_struct xfs_file_vm_ops;
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50
/*
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 * Clear the specified ranges to zero through either the pagecache or DAX.
 * Holes and unwritten extents will be left as-is as they already are zeroed.
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 */
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int
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xfs_zero_range(
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	struct xfs_inode	*ip,
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	xfs_off_t		pos,
	xfs_off_t		count,
	bool			*did_zero)
60
{
61
	return iomap_zero_range(VFS_I(ip), pos, count, NULL, &xfs_iomap_ops);
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}

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int
xfs_update_prealloc_flags(
	struct xfs_inode	*ip,
	enum xfs_prealloc_flags	flags)
{
	struct xfs_trans	*tp;
	int			error;

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	error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_writeid,
			0, 0, 0, &tp);
	if (error)
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		return error;

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

	if (!(flags & XFS_PREALLOC_INVISIBLE)) {
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		VFS_I(ip)->i_mode &= ~S_ISUID;
		if (VFS_I(ip)->i_mode & S_IXGRP)
			VFS_I(ip)->i_mode &= ~S_ISGID;
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		xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
	}

	if (flags & XFS_PREALLOC_SET)
		ip->i_d.di_flags |= XFS_DIFLAG_PREALLOC;
	if (flags & XFS_PREALLOC_CLEAR)
		ip->i_d.di_flags &= ~XFS_DIFLAG_PREALLOC;

	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	if (flags & XFS_PREALLOC_SYNC)
		xfs_trans_set_sync(tp);
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	return xfs_trans_commit(tp);
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}

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/*
 * Fsync operations on directories are much simpler than on regular files,
 * as there is no file data to flush, and thus also no need for explicit
 * cache flush operations, and there are no non-transaction metadata updates
 * on directories either.
 */
STATIC int
xfs_dir_fsync(
	struct file		*file,
	loff_t			start,
	loff_t			end,
	int			datasync)
{
	struct xfs_inode	*ip = XFS_I(file->f_mapping->host);
	struct xfs_mount	*mp = ip->i_mount;
	xfs_lsn_t		lsn = 0;

	trace_xfs_dir_fsync(ip);

	xfs_ilock(ip, XFS_ILOCK_SHARED);
	if (xfs_ipincount(ip))
		lsn = ip->i_itemp->ili_last_lsn;
	xfs_iunlock(ip, XFS_ILOCK_SHARED);

	if (!lsn)
		return 0;
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	return _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
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}

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STATIC int
xfs_file_fsync(
	struct file		*file,
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	loff_t			start,
	loff_t			end,
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	int			datasync)
{
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	struct inode		*inode = file->f_mapping->host;
	struct xfs_inode	*ip = XFS_I(inode);
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	struct xfs_mount	*mp = ip->i_mount;
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	int			error = 0;
	int			log_flushed = 0;
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	xfs_lsn_t		lsn = 0;
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	trace_xfs_file_fsync(ip);
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	error = filemap_write_and_wait_range(inode->i_mapping, start, end);
	if (error)
		return error;

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	if (XFS_FORCED_SHUTDOWN(mp))
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		return -EIO;
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	xfs_iflags_clear(ip, XFS_ITRUNCATED);

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	if (mp->m_flags & XFS_MOUNT_BARRIER) {
		/*
		 * If we have an RT and/or log subvolume we need to make sure
		 * to flush the write cache the device used for file data
		 * first.  This is to ensure newly written file data make
		 * it to disk before logging the new inode size in case of
		 * an extending write.
		 */
		if (XFS_IS_REALTIME_INODE(ip))
			xfs_blkdev_issue_flush(mp->m_rtdev_targp);
		else if (mp->m_logdev_targp != mp->m_ddev_targp)
			xfs_blkdev_issue_flush(mp->m_ddev_targp);
	}

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	/*
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	 * All metadata updates are logged, which means that we just have to
	 * flush the log up to the latest LSN that touched the inode. If we have
	 * concurrent fsync/fdatasync() calls, we need them to all block on the
	 * log force before we clear the ili_fsync_fields field. This ensures
	 * that we don't get a racing sync operation that does not wait for the
	 * metadata to hit the journal before returning. If we race with
	 * clearing the ili_fsync_fields, then all that will happen is the log
	 * force will do nothing as the lsn will already be on disk. We can't
	 * race with setting ili_fsync_fields because that is done under
	 * XFS_ILOCK_EXCL, and that can't happen because we hold the lock shared
	 * until after the ili_fsync_fields is cleared.
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	 */
	xfs_ilock(ip, XFS_ILOCK_SHARED);
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	if (xfs_ipincount(ip)) {
		if (!datasync ||
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		    (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
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			lsn = ip->i_itemp->ili_last_lsn;
	}
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186
	if (lsn) {
187
		error = _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, &log_flushed);
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		ip->i_itemp->ili_fsync_fields = 0;
	}
	xfs_iunlock(ip, XFS_ILOCK_SHARED);
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	/*
	 * If we only have a single device, and the log force about was
	 * a no-op we might have to flush the data device cache here.
	 * This can only happen for fdatasync/O_DSYNC if we were overwriting
	 * an already allocated file and thus do not have any metadata to
	 * commit.
	 */
	if ((mp->m_flags & XFS_MOUNT_BARRIER) &&
	    mp->m_logdev_targp == mp->m_ddev_targp &&
	    !XFS_IS_REALTIME_INODE(ip) &&
	    !log_flushed)
		xfs_blkdev_issue_flush(mp->m_ddev_targp);
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	return error;
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}

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STATIC ssize_t
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xfs_file_dio_aio_read(
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	struct kiocb		*iocb,
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	struct iov_iter		*to)
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{
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	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));
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	size_t			count = iov_iter_count(to);
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	ssize_t			ret;
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	trace_xfs_file_direct_read(ip, count, iocb->ki_pos);
218

219 220
	if (!count)
		return 0; /* skip atime */
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	file_accessed(iocb->ki_filp);

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	xfs_ilock(ip, XFS_IOLOCK_SHARED);
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	ret = iomap_dio_rw(iocb, to, &xfs_iomap_ops, NULL);
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	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
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	return ret;
}

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static noinline ssize_t
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xfs_file_dax_read(
	struct kiocb		*iocb,
	struct iov_iter		*to)
{
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	struct xfs_inode	*ip = XFS_I(iocb->ki_filp->f_mapping->host);
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	size_t			count = iov_iter_count(to);
	ssize_t			ret = 0;

	trace_xfs_file_dax_read(ip, count, iocb->ki_pos);

	if (!count)
		return 0; /* skip atime */

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	xfs_ilock(ip, XFS_IOLOCK_SHARED);
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	ret = dax_iomap_rw(iocb, to, &xfs_iomap_ops);
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	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
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	file_accessed(iocb->ki_filp);
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	return ret;
}

STATIC ssize_t
xfs_file_buffered_aio_read(
	struct kiocb		*iocb,
	struct iov_iter		*to)
{
	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));
	ssize_t			ret;

	trace_xfs_file_buffered_read(ip, iov_iter_count(to), iocb->ki_pos);
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	xfs_ilock(ip, XFS_IOLOCK_SHARED);
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	ret = generic_file_read_iter(iocb, to);
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	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
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	return ret;
}

STATIC ssize_t
xfs_file_read_iter(
	struct kiocb		*iocb,
	struct iov_iter		*to)
{
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	struct inode		*inode = file_inode(iocb->ki_filp);
	struct xfs_mount	*mp = XFS_I(inode)->i_mount;
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	ssize_t			ret = 0;

	XFS_STATS_INC(mp, xs_read_calls);

	if (XFS_FORCED_SHUTDOWN(mp))
		return -EIO;

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	if (IS_DAX(inode))
		ret = xfs_file_dax_read(iocb, to);
	else if (iocb->ki_flags & IOCB_DIRECT)
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		ret = xfs_file_dio_aio_read(iocb, to);
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	else
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		ret = xfs_file_buffered_aio_read(iocb, to);
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	if (ret > 0)
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		XFS_STATS_ADD(mp, xs_read_bytes, ret);
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	return ret;
}

/*
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 * Zero any on disk space between the current EOF and the new, larger EOF.
 *
 * This handles the normal case of zeroing the remainder of the last block in
 * the file and the unusual case of zeroing blocks out beyond the size of the
 * file.  This second case only happens with fixed size extents and when the
 * system crashes before the inode size was updated but after blocks were
 * allocated.
 *
 * Expects the iolock to be held exclusive, and will take the ilock internally.
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 */
int					/* error (positive) */
xfs_zero_eof(
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	struct xfs_inode	*ip,
	xfs_off_t		offset,		/* starting I/O offset */
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	xfs_fsize_t		isize,		/* current inode size */
	bool			*did_zeroing)
313
{
314
	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
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	ASSERT(offset > isize);

317
	trace_xfs_zero_eof(ip, isize, offset - isize);
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	return xfs_zero_range(ip, isize, offset - isize, did_zeroing);
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}

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/*
 * Common pre-write limit and setup checks.
 *
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 * Called with the iolocked held either shared and exclusive according to
 * @iolock, and returns with it held.  Might upgrade the iolock to exclusive
 * if called for a direct write beyond i_size.
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 */
STATIC ssize_t
xfs_file_aio_write_checks(
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	struct kiocb		*iocb,
	struct iov_iter		*from,
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	int			*iolock)
{
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	struct file		*file = iocb->ki_filp;
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	struct inode		*inode = file->f_mapping->host;
	struct xfs_inode	*ip = XFS_I(inode);
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	ssize_t			error = 0;
338
	size_t			count = iov_iter_count(from);
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	bool			drained_dio = false;
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341
restart:
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	error = generic_write_checks(iocb, from);
	if (error <= 0)
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		return error;

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	error = xfs_break_layouts(inode, iolock);
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	if (error)
		return error;

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	/*
	 * For changing security info in file_remove_privs() we need i_rwsem
	 * exclusively.
	 */
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	if (*iolock == XFS_IOLOCK_SHARED && !IS_NOSEC(inode)) {
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		xfs_iunlock(ip, *iolock);
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		*iolock = XFS_IOLOCK_EXCL;
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		xfs_ilock(ip, *iolock);
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		goto restart;
	}
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	/*
	 * If the offset is beyond the size of the file, we need to zero any
	 * blocks that fall between the existing EOF and the start of this
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	 * write.  If zeroing is needed and we are currently holding the
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	 * iolock shared, we need to update it to exclusive which implies
	 * having to redo all checks before.
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	 *
	 * We need to serialise against EOF updates that occur in IO
	 * completions here. We want to make sure that nobody is changing the
	 * size while we do this check until we have placed an IO barrier (i.e.
	 * hold the XFS_IOLOCK_EXCL) that prevents new IO from being dispatched.
	 * The spinlock effectively forms a memory barrier once we have the
	 * XFS_IOLOCK_EXCL so we are guaranteed to see the latest EOF value
	 * and hence be able to correctly determine if we need to run zeroing.
374
	 */
375
	spin_lock(&ip->i_flags_lock);
376
	if (iocb->ki_pos > i_size_read(inode)) {
377 378
		bool	zero = false;

379
		spin_unlock(&ip->i_flags_lock);
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		if (!drained_dio) {
			if (*iolock == XFS_IOLOCK_SHARED) {
382
				xfs_iunlock(ip, *iolock);
383
				*iolock = XFS_IOLOCK_EXCL;
384
				xfs_ilock(ip, *iolock);
385 386
				iov_iter_reexpand(from, count);
			}
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			/*
			 * We now have an IO submission barrier in place, but
			 * AIO can do EOF updates during IO completion and hence
			 * we now need to wait for all of them to drain. Non-AIO
			 * DIO will have drained before we are given the
			 * XFS_IOLOCK_EXCL, and so for most cases this wait is a
			 * no-op.
			 */
			inode_dio_wait(inode);
396
			drained_dio = true;
397 398
			goto restart;
		}
399
		error = xfs_zero_eof(ip, iocb->ki_pos, i_size_read(inode), &zero);
400 401
		if (error)
			return error;
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	} else
		spin_unlock(&ip->i_flags_lock);
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	/*
	 * Updating the timestamps will grab the ilock again from
	 * xfs_fs_dirty_inode, so we have to call it after dropping the
	 * lock above.  Eventually we should look into a way to avoid
	 * the pointless lock roundtrip.
	 */
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	if (likely(!(file->f_mode & FMODE_NOCMTIME))) {
		error = file_update_time(file);
		if (error)
			return error;
	}
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	/*
	 * If we're writing the file then make sure to clear the setuid and
	 * setgid bits if the process is not being run by root.  This keeps
	 * people from modifying setuid and setgid binaries.
	 */
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	if (!IS_NOSEC(inode))
		return file_remove_privs(file);
	return 0;
425 426
}

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static int
xfs_dio_write_end_io(
	struct kiocb		*iocb,
	ssize_t			size,
	unsigned		flags)
{
	struct inode		*inode = file_inode(iocb->ki_filp);
	struct xfs_inode	*ip = XFS_I(inode);
	loff_t			offset = iocb->ki_pos;
	bool			update_size = false;
	int			error = 0;

	trace_xfs_end_io_direct_write(ip, offset, size);

	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
		return -EIO;

	if (size <= 0)
		return size;

	/*
	 * We need to update the in-core inode size here so that we don't end up
	 * with the on-disk inode size being outside the in-core inode size. We
	 * have no other method of updating EOF for AIO, so always do it here
	 * if necessary.
	 *
	 * We need to lock the test/set EOF update as we can be racing with
	 * other IO completions here to update the EOF. Failing to serialise
	 * here can result in EOF moving backwards and Bad Things Happen when
	 * that occurs.
	 */
	spin_lock(&ip->i_flags_lock);
	if (offset + size > i_size_read(inode)) {
		i_size_write(inode, offset + size);
		update_size = true;
	}
	spin_unlock(&ip->i_flags_lock);

	if (flags & IOMAP_DIO_COW) {
		error = xfs_reflink_end_cow(ip, offset, size);
		if (error)
			return error;
	}

	if (flags & IOMAP_DIO_UNWRITTEN)
		error = xfs_iomap_write_unwritten(ip, offset, size);
	else if (update_size)
		error = xfs_setfilesize(ip, offset, size);

	return error;
}

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/*
 * xfs_file_dio_aio_write - handle direct IO writes
 *
 * Lock the inode appropriately to prepare for and issue a direct IO write.
483
 * By separating it from the buffered write path we remove all the tricky to
484 485
 * follow locking changes and looping.
 *
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 * If there are cached pages or we're extending the file, we need IOLOCK_EXCL
 * until we're sure the bytes at the new EOF have been zeroed and/or the cached
 * pages are flushed out.
 *
 * In most cases the direct IO writes will be done holding IOLOCK_SHARED
 * allowing them to be done in parallel with reads and other direct IO writes.
 * However, if the IO is not aligned to filesystem blocks, the direct IO layer
 * needs to do sub-block zeroing and that requires serialisation against other
 * direct IOs to the same block. In this case we need to serialise the
 * submission of the unaligned IOs so that we don't get racing block zeroing in
 * the dio layer.  To avoid the problem with aio, we also need to wait for
 * outstanding IOs to complete so that unwritten extent conversion is completed
 * before we try to map the overlapping block. This is currently implemented by
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 * hitting it with a big hammer (i.e. inode_dio_wait()).
500
 *
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 * Returns with locks held indicated by @iolock and errors indicated by
 * negative return values.
 */
STATIC ssize_t
xfs_file_dio_aio_write(
	struct kiocb		*iocb,
507
	struct iov_iter		*from)
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{
	struct file		*file = iocb->ki_filp;
	struct address_space	*mapping = file->f_mapping;
	struct inode		*inode = mapping->host;
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	ssize_t			ret = 0;
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	int			unaligned_io = 0;
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	int			iolock;
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	size_t			count = iov_iter_count(from);
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	struct xfs_buftarg      *target = XFS_IS_REALTIME_INODE(ip) ?
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					mp->m_rtdev_targp : mp->m_ddev_targp;

521
	/* DIO must be aligned to device logical sector size */
522
	if ((iocb->ki_pos | count) & target->bt_logical_sectormask)
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		return -EINVAL;
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525
	/*
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	 * Don't take the exclusive iolock here unless the I/O is unaligned to
	 * the file system block size.  We don't need to consider the EOF
	 * extension case here because xfs_file_aio_write_checks() will relock
	 * the inode as necessary for EOF zeroing cases and fill out the new
	 * inode size as appropriate.
531
	 */
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	if ((iocb->ki_pos & mp->m_blockmask) ||
	    ((iocb->ki_pos + count) & mp->m_blockmask)) {
		unaligned_io = 1;
535
		iolock = XFS_IOLOCK_EXCL;
536
	} else {
537
		iolock = XFS_IOLOCK_SHARED;
538
	}
539

540
	xfs_ilock(ip, iolock);
541

542
	ret = xfs_file_aio_write_checks(iocb, from, &iolock);
543
	if (ret)
544
		goto out;
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	count = iov_iter_count(from);
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547 548
	/*
	 * If we are doing unaligned IO, wait for all other IO to drain,
549 550
	 * otherwise demote the lock if we had to take the exclusive lock
	 * for other reasons in xfs_file_aio_write_checks.
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	 */
	if (unaligned_io)
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Christoph Hellwig 已提交
553
		inode_dio_wait(inode);
554
	else if (iolock == XFS_IOLOCK_EXCL) {
555
		xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);
556
		iolock = XFS_IOLOCK_SHARED;
557 558
	}

C
Christoph Hellwig 已提交
559
	trace_xfs_file_direct_write(ip, count, iocb->ki_pos);
560

561 562 563 564 565 566 567
	/* If this is a block-aligned directio CoW, remap immediately. */
	if (xfs_is_reflink_inode(ip) && !unaligned_io) {
		ret = xfs_reflink_allocate_cow_range(ip, iocb->ki_pos, count);
		if (ret)
			goto out;
	}

C
Christoph Hellwig 已提交
568
	ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, xfs_dio_write_end_io);
569
out:
570
	xfs_iunlock(ip, iolock);
571

572
	/*
573 574
	 * No fallback to buffered IO on errors for XFS, direct IO will either
	 * complete fully or fail.
575
	 */
576 577 578 579
	ASSERT(ret < 0 || ret == count);
	return ret;
}

580
static noinline ssize_t
581 582 583 584
xfs_file_dax_write(
	struct kiocb		*iocb,
	struct iov_iter		*from)
{
585
	struct inode		*inode = iocb->ki_filp->f_mapping->host;
586
	struct xfs_inode	*ip = XFS_I(inode);
587
	int			iolock = XFS_IOLOCK_EXCL;
588 589 590
	ssize_t			ret, error = 0;
	size_t			count;
	loff_t			pos;
591

592
	xfs_ilock(ip, iolock);
593 594 595 596
	ret = xfs_file_aio_write_checks(iocb, from, &iolock);
	if (ret)
		goto out;

597 598
	pos = iocb->ki_pos;
	count = iov_iter_count(from);
599

600
	trace_xfs_file_dax_write(ip, count, pos);
601
	ret = dax_iomap_rw(iocb, from, &xfs_iomap_ops);
602 603 604
	if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
		i_size_write(inode, iocb->ki_pos);
		error = xfs_setfilesize(ip, pos, ret);
605 606
	}
out:
607
	xfs_iunlock(ip, iolock);
608
	return error ? error : ret;
609 610
}

611
STATIC ssize_t
612
xfs_file_buffered_aio_write(
613
	struct kiocb		*iocb,
614
	struct iov_iter		*from)
615 616 617 618
{
	struct file		*file = iocb->ki_filp;
	struct address_space	*mapping = file->f_mapping;
	struct inode		*inode = mapping->host;
619
	struct xfs_inode	*ip = XFS_I(inode);
620 621
	ssize_t			ret;
	int			enospc = 0;
622
	int			iolock = XFS_IOLOCK_EXCL;
623

624
	xfs_ilock(ip, iolock);
625

626
	ret = xfs_file_aio_write_checks(iocb, from, &iolock);
627
	if (ret)
628
		goto out;
629 630

	/* We can write back this queue in page reclaim */
631
	current->backing_dev_info = inode_to_bdi(inode);
632 633

write_retry:
C
Christoph Hellwig 已提交
634
	trace_xfs_file_buffered_write(ip, iov_iter_count(from), iocb->ki_pos);
635
	ret = iomap_file_buffered_write(iocb, from, &xfs_iomap_ops);
636
	if (likely(ret >= 0))
637
		iocb->ki_pos += ret;
638

639
	/*
640 641 642 643 644 645 646
	 * If we hit a space limit, try to free up some lingering preallocated
	 * space before returning an error. In the case of ENOSPC, first try to
	 * write back all dirty inodes to free up some of the excess reserved
	 * metadata space. This reduces the chances that the eofblocks scan
	 * waits on dirty mappings. Since xfs_flush_inodes() is serialized, this
	 * also behaves as a filter to prevent too many eofblocks scans from
	 * running at the same time.
647
	 */
648 649 650 651
	if (ret == -EDQUOT && !enospc) {
		enospc = xfs_inode_free_quota_eofblocks(ip);
		if (enospc)
			goto write_retry;
652 653 654
		enospc = xfs_inode_free_quota_cowblocks(ip);
		if (enospc)
			goto write_retry;
655 656 657
	} else if (ret == -ENOSPC && !enospc) {
		struct xfs_eofblocks eofb = {0};

658
		enospc = 1;
D
Dave Chinner 已提交
659
		xfs_flush_inodes(ip->i_mount);
660 661 662
		eofb.eof_scan_owner = ip->i_ino; /* for locking */
		eofb.eof_flags = XFS_EOF_FLAGS_SYNC;
		xfs_icache_free_eofblocks(ip->i_mount, &eofb);
D
Dave Chinner 已提交
663
		goto write_retry;
664
	}
665

666
	current->backing_dev_info = NULL;
667
out:
668
	xfs_iunlock(ip, iolock);
669 670 671 672
	return ret;
}

STATIC ssize_t
A
Al Viro 已提交
673
xfs_file_write_iter(
674
	struct kiocb		*iocb,
A
Al Viro 已提交
675
	struct iov_iter		*from)
676 677 678 679 680 681
{
	struct file		*file = iocb->ki_filp;
	struct address_space	*mapping = file->f_mapping;
	struct inode		*inode = mapping->host;
	struct xfs_inode	*ip = XFS_I(inode);
	ssize_t			ret;
A
Al Viro 已提交
682
	size_t			ocount = iov_iter_count(from);
683

684
	XFS_STATS_INC(ip->i_mount, xs_write_calls);
685 686 687 688

	if (ocount == 0)
		return 0;

A
Al Viro 已提交
689 690
	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
		return -EIO;
691

692 693
	if (IS_DAX(inode))
		ret = xfs_file_dax_write(iocb, from);
694 695 696 697 698 699 700
	else if (iocb->ki_flags & IOCB_DIRECT) {
		/*
		 * Allow a directio write to fall back to a buffered
		 * write *only* in the case that we're doing a reflink
		 * CoW.  In all other directio scenarios we do not
		 * allow an operation to fall back to buffered mode.
		 */
A
Al Viro 已提交
701
		ret = xfs_file_dio_aio_write(iocb, from);
702 703 704 705
		if (ret == -EREMCHG)
			goto buffered;
	} else {
buffered:
A
Al Viro 已提交
706
		ret = xfs_file_buffered_aio_write(iocb, from);
707
	}
708

709
	if (ret > 0) {
710
		XFS_STATS_ADD(ip->i_mount, xs_write_bytes, ret);
711

712
		/* Handle various SYNC-type writes */
713
		ret = generic_write_sync(iocb, ret);
714
	}
715
	return ret;
716 717
}

718 719 720
#define	XFS_FALLOC_FL_SUPPORTED						\
		(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |		\
		 FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |	\
721
		 FALLOC_FL_INSERT_RANGE | FALLOC_FL_UNSHARE_RANGE)
722

723 724
STATIC long
xfs_file_fallocate(
725 726 727 728
	struct file		*file,
	int			mode,
	loff_t			offset,
	loff_t			len)
729
{
730 731 732
	struct inode		*inode = file_inode(file);
	struct xfs_inode	*ip = XFS_I(inode);
	long			error;
733
	enum xfs_prealloc_flags	flags = 0;
734
	uint			iolock = XFS_IOLOCK_EXCL;
735
	loff_t			new_size = 0;
736
	bool			do_file_insert = 0;
737

738 739
	if (!S_ISREG(inode->i_mode))
		return -EINVAL;
740
	if (mode & ~XFS_FALLOC_FL_SUPPORTED)
741 742
		return -EOPNOTSUPP;

743
	xfs_ilock(ip, iolock);
744
	error = xfs_break_layouts(inode, &iolock);
745 746 747
	if (error)
		goto out_unlock;

748 749 750
	xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
	iolock |= XFS_MMAPLOCK_EXCL;

751 752 753 754
	if (mode & FALLOC_FL_PUNCH_HOLE) {
		error = xfs_free_file_space(ip, offset, len);
		if (error)
			goto out_unlock;
755 756 757 758
	} else if (mode & FALLOC_FL_COLLAPSE_RANGE) {
		unsigned blksize_mask = (1 << inode->i_blkbits) - 1;

		if (offset & blksize_mask || len & blksize_mask) {
D
Dave Chinner 已提交
759
			error = -EINVAL;
760 761 762
			goto out_unlock;
		}

763 764 765 766 767
		/*
		 * There is no need to overlap collapse range with EOF,
		 * in which case it is effectively a truncate operation
		 */
		if (offset + len >= i_size_read(inode)) {
D
Dave Chinner 已提交
768
			error = -EINVAL;
769 770 771
			goto out_unlock;
		}

772 773 774 775 776
		new_size = i_size_read(inode) - len;

		error = xfs_collapse_file_space(ip, offset, len);
		if (error)
			goto out_unlock;
777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797
	} else if (mode & FALLOC_FL_INSERT_RANGE) {
		unsigned blksize_mask = (1 << inode->i_blkbits) - 1;

		new_size = i_size_read(inode) + len;
		if (offset & blksize_mask || len & blksize_mask) {
			error = -EINVAL;
			goto out_unlock;
		}

		/* check the new inode size does not wrap through zero */
		if (new_size > inode->i_sb->s_maxbytes) {
			error = -EFBIG;
			goto out_unlock;
		}

		/* Offset should be less than i_size */
		if (offset >= i_size_read(inode)) {
			error = -EINVAL;
			goto out_unlock;
		}
		do_file_insert = 1;
798
	} else {
799 800
		flags |= XFS_PREALLOC_SET;

801 802 803
		if (!(mode & FALLOC_FL_KEEP_SIZE) &&
		    offset + len > i_size_read(inode)) {
			new_size = offset + len;
D
Dave Chinner 已提交
804
			error = inode_newsize_ok(inode, new_size);
805 806 807
			if (error)
				goto out_unlock;
		}
808

809 810
		if (mode & FALLOC_FL_ZERO_RANGE)
			error = xfs_zero_file_space(ip, offset, len);
811 812 813 814 815 816
		else {
			if (mode & FALLOC_FL_UNSHARE_RANGE) {
				error = xfs_reflink_unshare(ip, offset, len);
				if (error)
					goto out_unlock;
			}
817 818
			error = xfs_alloc_file_space(ip, offset, len,
						     XFS_BMAPI_PREALLOC);
819
		}
820 821 822 823
		if (error)
			goto out_unlock;
	}

824
	if (file->f_flags & O_DSYNC)
825 826 827
		flags |= XFS_PREALLOC_SYNC;

	error = xfs_update_prealloc_flags(ip, flags);
828 829 830 831 832 833 834 835 836
	if (error)
		goto out_unlock;

	/* Change file size if needed */
	if (new_size) {
		struct iattr iattr;

		iattr.ia_valid = ATTR_SIZE;
		iattr.ia_size = new_size;
837
		error = xfs_vn_setattr_size(file_dentry(file), &iattr);
838 839
		if (error)
			goto out_unlock;
840 841
	}

842 843 844 845 846 847 848 849 850
	/*
	 * Perform hole insertion now that the file size has been
	 * updated so that if we crash during the operation we don't
	 * leave shifted extents past EOF and hence losing access to
	 * the data that is contained within them.
	 */
	if (do_file_insert)
		error = xfs_insert_file_space(ip, offset, len);

851
out_unlock:
852
	xfs_iunlock(ip, iolock);
D
Dave Chinner 已提交
853
	return error;
854 855
}

856 857 858 859 860 861 862 863 864 865 866
STATIC ssize_t
xfs_file_copy_range(
	struct file	*file_in,
	loff_t		pos_in,
	struct file	*file_out,
	loff_t		pos_out,
	size_t		len,
	unsigned int	flags)
{
	int		error;

867
	error = xfs_reflink_remap_range(file_in, pos_in, file_out, pos_out,
868
				     len, false);
869 870 871 872 873 874 875 876 877 878 879 880 881
	if (error)
		return error;
	return len;
}

STATIC int
xfs_file_clone_range(
	struct file	*file_in,
	loff_t		pos_in,
	struct file	*file_out,
	loff_t		pos_out,
	u64		len)
{
882
	return xfs_reflink_remap_range(file_in, pos_in, file_out, pos_out,
883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904
				     len, false);
}

#define XFS_MAX_DEDUPE_LEN	(16 * 1024 * 1024)
STATIC ssize_t
xfs_file_dedupe_range(
	struct file	*src_file,
	u64		loff,
	u64		len,
	struct file	*dst_file,
	u64		dst_loff)
{
	int		error;

	/*
	 * Limit the total length we will dedupe for each operation.
	 * This is intended to bound the total time spent in this
	 * ioctl to something sane.
	 */
	if (len > XFS_MAX_DEDUPE_LEN)
		len = XFS_MAX_DEDUPE_LEN;

905
	error = xfs_reflink_remap_range(src_file, loff, dst_file, dst_loff,
906 907 908 909
				     len, true);
	if (error)
		return error;
	return len;
910
}
911

L
Linus Torvalds 已提交
912
STATIC int
913
xfs_file_open(
L
Linus Torvalds 已提交
914
	struct inode	*inode,
915
	struct file	*file)
L
Linus Torvalds 已提交
916
{
917
	if (!(file->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
L
Linus Torvalds 已提交
918
		return -EFBIG;
919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940
	if (XFS_FORCED_SHUTDOWN(XFS_M(inode->i_sb)))
		return -EIO;
	return 0;
}

STATIC int
xfs_dir_open(
	struct inode	*inode,
	struct file	*file)
{
	struct xfs_inode *ip = XFS_I(inode);
	int		mode;
	int		error;

	error = xfs_file_open(inode, file);
	if (error)
		return error;

	/*
	 * If there are any blocks, read-ahead block 0 as we're almost
	 * certain to have the next operation be a read there.
	 */
941
	mode = xfs_ilock_data_map_shared(ip);
942
	if (ip->i_d.di_nextents > 0)
943
		xfs_dir3_data_readahead(ip, 0, -1);
944 945
	xfs_iunlock(ip, mode);
	return 0;
L
Linus Torvalds 已提交
946 947 948
}

STATIC int
949
xfs_file_release(
L
Linus Torvalds 已提交
950 951 952
	struct inode	*inode,
	struct file	*filp)
{
D
Dave Chinner 已提交
953
	return xfs_release(XFS_I(inode));
L
Linus Torvalds 已提交
954 955 956
}

STATIC int
957
xfs_file_readdir(
A
Al Viro 已提交
958 959
	struct file	*file,
	struct dir_context *ctx)
L
Linus Torvalds 已提交
960
{
A
Al Viro 已提交
961
	struct inode	*inode = file_inode(file);
962
	xfs_inode_t	*ip = XFS_I(inode);
C
Christoph Hellwig 已提交
963 964 965 966 967 968 969 970 971 972 973 974
	size_t		bufsize;

	/*
	 * The Linux API doesn't pass down the total size of the buffer
	 * we read into down to the filesystem.  With the filldir concept
	 * it's not needed for correct information, but the XFS dir2 leaf
	 * code wants an estimate of the buffer size to calculate it's
	 * readahead window and size the buffers used for mapping to
	 * physical blocks.
	 *
	 * Try to give it an estimate that's good enough, maybe at some
	 * point we can change the ->readdir prototype to include the
E
Eric Sandeen 已提交
975
	 * buffer size.  For now we use the current glibc buffer size.
C
Christoph Hellwig 已提交
976
	 */
E
Eric Sandeen 已提交
977
	bufsize = (size_t)min_t(loff_t, 32768, ip->i_d.di_size);
C
Christoph Hellwig 已提交
978

979
	return xfs_readdir(ip, ctx, bufsize);
L
Linus Torvalds 已提交
980 981
}

982 983
/*
 * This type is designed to indicate the type of offset we would like
984
 * to search from page cache for xfs_seek_hole_data().
985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040
 */
enum {
	HOLE_OFF = 0,
	DATA_OFF,
};

/*
 * Lookup the desired type of offset from the given page.
 *
 * On success, return true and the offset argument will point to the
 * start of the region that was found.  Otherwise this function will
 * return false and keep the offset argument unchanged.
 */
STATIC bool
xfs_lookup_buffer_offset(
	struct page		*page,
	loff_t			*offset,
	unsigned int		type)
{
	loff_t			lastoff = page_offset(page);
	bool			found = false;
	struct buffer_head	*bh, *head;

	bh = head = page_buffers(page);
	do {
		/*
		 * Unwritten extents that have data in the page
		 * cache covering them can be identified by the
		 * BH_Unwritten state flag.  Pages with multiple
		 * buffers might have a mix of holes, data and
		 * unwritten extents - any buffer with valid
		 * data in it should have BH_Uptodate flag set
		 * on it.
		 */
		if (buffer_unwritten(bh) ||
		    buffer_uptodate(bh)) {
			if (type == DATA_OFF)
				found = true;
		} else {
			if (type == HOLE_OFF)
				found = true;
		}

		if (found) {
			*offset = lastoff;
			break;
		}
		lastoff += bh->b_size;
	} while ((bh = bh->b_this_page) != head);

	return found;
}

/*
 * This routine is called to find out and return a data or hole offset
 * from the page cache for unwritten extents according to the desired
1041
 * type for xfs_seek_hole_data().
1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069
 *
 * The argument offset is used to tell where we start to search from the
 * page cache.  Map is used to figure out the end points of the range to
 * lookup pages.
 *
 * Return true if the desired type of offset was found, and the argument
 * offset is filled with that address.  Otherwise, return false and keep
 * offset unchanged.
 */
STATIC bool
xfs_find_get_desired_pgoff(
	struct inode		*inode,
	struct xfs_bmbt_irec	*map,
	unsigned int		type,
	loff_t			*offset)
{
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	struct pagevec		pvec;
	pgoff_t			index;
	pgoff_t			end;
	loff_t			endoff;
	loff_t			startoff = *offset;
	loff_t			lastoff = startoff;
	bool			found = false;

	pagevec_init(&pvec, 0);

1070
	index = startoff >> PAGE_SHIFT;
1071
	endoff = XFS_FSB_TO_B(mp, map->br_startoff + map->br_blockcount);
1072
	end = endoff >> PAGE_SHIFT;
1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199
	do {
		int		want;
		unsigned	nr_pages;
		unsigned int	i;

		want = min_t(pgoff_t, end - index, PAGEVEC_SIZE);
		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
					  want);
		/*
		 * No page mapped into given range.  If we are searching holes
		 * and if this is the first time we got into the loop, it means
		 * that the given offset is landed in a hole, return it.
		 *
		 * If we have already stepped through some block buffers to find
		 * holes but they all contains data.  In this case, the last
		 * offset is already updated and pointed to the end of the last
		 * mapped page, if it does not reach the endpoint to search,
		 * that means there should be a hole between them.
		 */
		if (nr_pages == 0) {
			/* Data search found nothing */
			if (type == DATA_OFF)
				break;

			ASSERT(type == HOLE_OFF);
			if (lastoff == startoff || lastoff < endoff) {
				found = true;
				*offset = lastoff;
			}
			break;
		}

		/*
		 * At lease we found one page.  If this is the first time we
		 * step into the loop, and if the first page index offset is
		 * greater than the given search offset, a hole was found.
		 */
		if (type == HOLE_OFF && lastoff == startoff &&
		    lastoff < page_offset(pvec.pages[0])) {
			found = true;
			break;
		}

		for (i = 0; i < nr_pages; i++) {
			struct page	*page = pvec.pages[i];
			loff_t		b_offset;

			/*
			 * At this point, the page may be truncated or
			 * invalidated (changing page->mapping to NULL),
			 * or even swizzled back from swapper_space to tmpfs
			 * file mapping. However, page->index will not change
			 * because we have a reference on the page.
			 *
			 * Searching done if the page index is out of range.
			 * If the current offset is not reaches the end of
			 * the specified search range, there should be a hole
			 * between them.
			 */
			if (page->index > end) {
				if (type == HOLE_OFF && lastoff < endoff) {
					*offset = lastoff;
					found = true;
				}
				goto out;
			}

			lock_page(page);
			/*
			 * Page truncated or invalidated(page->mapping == NULL).
			 * We can freely skip it and proceed to check the next
			 * page.
			 */
			if (unlikely(page->mapping != inode->i_mapping)) {
				unlock_page(page);
				continue;
			}

			if (!page_has_buffers(page)) {
				unlock_page(page);
				continue;
			}

			found = xfs_lookup_buffer_offset(page, &b_offset, type);
			if (found) {
				/*
				 * The found offset may be less than the start
				 * point to search if this is the first time to
				 * come here.
				 */
				*offset = max_t(loff_t, startoff, b_offset);
				unlock_page(page);
				goto out;
			}

			/*
			 * We either searching data but nothing was found, or
			 * searching hole but found a data buffer.  In either
			 * case, probably the next page contains the desired
			 * things, update the last offset to it so.
			 */
			lastoff = page_offset(page) + PAGE_SIZE;
			unlock_page(page);
		}

		/*
		 * The number of returned pages less than our desired, search
		 * done.  In this case, nothing was found for searching data,
		 * but we found a hole behind the last offset.
		 */
		if (nr_pages < want) {
			if (type == HOLE_OFF) {
				*offset = lastoff;
				found = true;
			}
			break;
		}

		index = pvec.pages[i - 1]->index + 1;
		pagevec_release(&pvec);
	} while (index <= end);

out:
	pagevec_release(&pvec);
	return found;
}

1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210
/*
 * caller must lock inode with xfs_ilock_data_map_shared,
 * can we craft an appropriate ASSERT?
 *
 * end is because the VFS-level lseek interface is defined such that any
 * offset past i_size shall return -ENXIO, but we use this for quota code
 * which does not maintain i_size, and we want to SEEK_DATA past i_size.
 */
loff_t
__xfs_seek_hole_data(
	struct inode		*inode,
1211
	loff_t			start,
1212
	loff_t			end,
1213
	int			whence)
1214 1215 1216 1217 1218
{
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	loff_t			uninitialized_var(offset);
	xfs_fileoff_t		fsbno;
1219
	xfs_filblks_t		lastbno;
1220 1221
	int			error;

1222
	if (start >= end) {
D
Dave Chinner 已提交
1223
		error = -ENXIO;
1224
		goto out_error;
1225 1226 1227 1228 1229 1230
	}

	/*
	 * Try to read extents from the first block indicated
	 * by fsbno to the end block of the file.
	 */
1231
	fsbno = XFS_B_TO_FSBT(mp, start);
1232
	lastbno = XFS_B_TO_FSB(mp, end);
1233

1234 1235 1236 1237
	for (;;) {
		struct xfs_bmbt_irec	map[2];
		int			nmap = 2;
		unsigned int		i;
1238

1239
		error = xfs_bmapi_read(ip, fsbno, lastbno - fsbno, map, &nmap,
1240 1241
				       XFS_BMAPI_ENTIRE);
		if (error)
1242
			goto out_error;
1243

1244 1245
		/* No extents at given offset, must be beyond EOF */
		if (nmap == 0) {
D
Dave Chinner 已提交
1246
			error = -ENXIO;
1247
			goto out_error;
1248 1249 1250 1251 1252 1253
		}

		for (i = 0; i < nmap; i++) {
			offset = max_t(loff_t, start,
				       XFS_FSB_TO_B(mp, map[i].br_startoff));

1254 1255 1256 1257 1258 1259 1260 1261 1262 1263
			/* Landed in the hole we wanted? */
			if (whence == SEEK_HOLE &&
			    map[i].br_startblock == HOLESTARTBLOCK)
				goto out;

			/* Landed in the data extent we wanted? */
			if (whence == SEEK_DATA &&
			    (map[i].br_startblock == DELAYSTARTBLOCK ||
			     (map[i].br_state == XFS_EXT_NORM &&
			      !isnullstartblock(map[i].br_startblock))))
1264 1265 1266
				goto out;

			/*
1267 1268
			 * Landed in an unwritten extent, try to search
			 * for hole or data from page cache.
1269 1270 1271
			 */
			if (map[i].br_state == XFS_EXT_UNWRITTEN) {
				if (xfs_find_get_desired_pgoff(inode, &map[i],
1272 1273
				      whence == SEEK_HOLE ? HOLE_OFF : DATA_OFF,
							&offset))
1274 1275 1276 1277 1278
					goto out;
			}
		}

		/*
1279 1280
		 * We only received one extent out of the two requested. This
		 * means we've hit EOF and didn't find what we are looking for.
1281
		 */
1282
		if (nmap == 1) {
1283 1284 1285 1286 1287 1288
			/*
			 * If we were looking for a hole, set offset to
			 * the end of the file (i.e., there is an implicit
			 * hole at the end of any file).
		 	 */
			if (whence == SEEK_HOLE) {
1289
				offset = end;
1290 1291 1292 1293 1294 1295
				break;
			}
			/*
			 * If we were looking for data, it's nowhere to be found
			 */
			ASSERT(whence == SEEK_DATA);
D
Dave Chinner 已提交
1296
			error = -ENXIO;
1297
			goto out_error;
1298 1299
		}

1300 1301 1302 1303
		ASSERT(i > 1);

		/*
		 * Nothing was found, proceed to the next round of search
1304
		 * if the next reading offset is not at or beyond EOF.
1305 1306 1307
		 */
		fsbno = map[i - 1].br_startoff + map[i - 1].br_blockcount;
		start = XFS_FSB_TO_B(mp, fsbno);
1308
		if (start >= end) {
1309
			if (whence == SEEK_HOLE) {
1310
				offset = end;
1311 1312 1313
				break;
			}
			ASSERT(whence == SEEK_DATA);
D
Dave Chinner 已提交
1314
			error = -ENXIO;
1315
			goto out_error;
1316
		}
1317 1318
	}

1319 1320
out:
	/*
1321
	 * If at this point we have found the hole we wanted, the returned
1322
	 * offset may be bigger than the file size as it may be aligned to
1323
	 * page boundary for unwritten extents.  We need to deal with this
1324 1325
	 * situation in particular.
	 */
1326
	if (whence == SEEK_HOLE)
1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359
		offset = min_t(loff_t, offset, end);

	return offset;

out_error:
	return error;
}

STATIC loff_t
xfs_seek_hole_data(
	struct file		*file,
	loff_t			start,
	int			whence)
{
	struct inode		*inode = file->f_mapping->host;
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	uint			lock;
	loff_t			offset, end;
	int			error = 0;

	if (XFS_FORCED_SHUTDOWN(mp))
		return -EIO;

	lock = xfs_ilock_data_map_shared(ip);

	end = i_size_read(inode);
	offset = __xfs_seek_hole_data(inode, start, end, whence);
	if (offset < 0) {
		error = offset;
		goto out_unlock;
	}

J
Jie Liu 已提交
1360
	offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
1361 1362

out_unlock:
1363
	xfs_iunlock(ip, lock);
1364 1365

	if (error)
D
Dave Chinner 已提交
1366
		return error;
1367 1368 1369 1370 1371 1372 1373
	return offset;
}

STATIC loff_t
xfs_file_llseek(
	struct file	*file,
	loff_t		offset,
1374
	int		whence)
1375
{
1376
	switch (whence) {
1377 1378 1379
	case SEEK_END:
	case SEEK_CUR:
	case SEEK_SET:
1380
		return generic_file_llseek(file, offset, whence);
1381
	case SEEK_HOLE:
1382
	case SEEK_DATA:
1383
		return xfs_seek_hole_data(file, offset, whence);
1384 1385 1386 1387 1388
	default:
		return -EINVAL;
	}
}

1389 1390 1391 1392 1393
/*
 * Locking for serialisation of IO during page faults. This results in a lock
 * ordering of:
 *
 * mmap_sem (MM)
1394
 *   sb_start_pagefault(vfs, freeze)
1395
 *     i_mmaplock (XFS - truncate serialisation)
1396 1397
 *       page_lock (MM)
 *         i_lock (XFS - extent map serialisation)
1398 1399
 */

1400 1401 1402 1403 1404
/*
 * mmap()d file has taken write protection fault and is being made writable. We
 * can set the page state up correctly for a writable page, which means we can
 * do correct delalloc accounting (ENOSPC checking!) and unwritten extent
 * mapping.
1405 1406
 */
STATIC int
1407
xfs_filemap_page_mkwrite(
1408 1409 1410
	struct vm_area_struct	*vma,
	struct vm_fault		*vmf)
{
1411
	struct inode		*inode = file_inode(vma->vm_file);
1412
	int			ret;
1413

1414
	trace_xfs_filemap_page_mkwrite(XFS_I(inode));
1415

1416
	sb_start_pagefault(inode->i_sb);
1417
	file_update_time(vma->vm_file);
1418
	xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
1419

1420
	if (IS_DAX(inode)) {
1421
		ret = dax_iomap_fault(vma, vmf, &xfs_iomap_ops);
1422
	} else {
1423
		ret = iomap_page_mkwrite(vma, vmf, &xfs_iomap_ops);
1424 1425 1426 1427 1428 1429 1430
		ret = block_page_mkwrite_return(ret);
	}

	xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
	sb_end_pagefault(inode->i_sb);

	return ret;
1431 1432
}

1433
STATIC int
1434
xfs_filemap_fault(
1435 1436 1437
	struct vm_area_struct	*vma,
	struct vm_fault		*vmf)
{
1438
	struct inode		*inode = file_inode(vma->vm_file);
1439
	int			ret;
1440

1441
	trace_xfs_filemap_fault(XFS_I(inode));
1442

1443
	/* DAX can shortcut the normal fault path on write faults! */
1444
	if ((vmf->flags & FAULT_FLAG_WRITE) && IS_DAX(inode))
1445
		return xfs_filemap_page_mkwrite(vma, vmf);
1446

1447
	xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
C
Christoph Hellwig 已提交
1448
	if (IS_DAX(inode))
1449
		ret = dax_iomap_fault(vma, vmf, &xfs_iomap_ops);
C
Christoph Hellwig 已提交
1450
	else
1451 1452
		ret = filemap_fault(vma, vmf);
	xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
1453

1454 1455 1456
	return ret;
}

1457 1458 1459 1460 1461 1462 1463
/*
 * Similar to xfs_filemap_fault(), the DAX fault path can call into here on
 * both read and write faults. Hence we need to handle both cases. There is no
 * ->pmd_mkwrite callout for huge pages, so we have a single function here to
 * handle both cases here. @flags carries the information on the type of fault
 * occuring.
 */
M
Matthew Wilcox 已提交
1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479
STATIC int
xfs_filemap_pmd_fault(
	struct vm_area_struct	*vma,
	unsigned long		addr,
	pmd_t			*pmd,
	unsigned int		flags)
{
	struct inode		*inode = file_inode(vma->vm_file);
	struct xfs_inode	*ip = XFS_I(inode);
	int			ret;

	if (!IS_DAX(inode))
		return VM_FAULT_FALLBACK;

	trace_xfs_filemap_pmd_fault(ip);

1480 1481 1482 1483 1484
	if (flags & FAULT_FLAG_WRITE) {
		sb_start_pagefault(inode->i_sb);
		file_update_time(vma->vm_file);
	}

M
Matthew Wilcox 已提交
1485
	xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
1486
	ret = dax_iomap_pmd_fault(vma, addr, pmd, flags, &xfs_iomap_ops);
M
Matthew Wilcox 已提交
1487 1488
	xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);

1489 1490
	if (flags & FAULT_FLAG_WRITE)
		sb_end_pagefault(inode->i_sb);
M
Matthew Wilcox 已提交
1491 1492 1493 1494

	return ret;
}

1495 1496 1497
/*
 * pfn_mkwrite was originally inteneded to ensure we capture time stamp
 * updates on write faults. In reality, it's need to serialise against
1498 1499
 * truncate similar to page_mkwrite. Hence we cycle the XFS_MMAPLOCK_SHARED
 * to ensure we serialise the fault barrier in place.
1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521
 */
static int
xfs_filemap_pfn_mkwrite(
	struct vm_area_struct	*vma,
	struct vm_fault		*vmf)
{

	struct inode		*inode = file_inode(vma->vm_file);
	struct xfs_inode	*ip = XFS_I(inode);
	int			ret = VM_FAULT_NOPAGE;
	loff_t			size;

	trace_xfs_filemap_pfn_mkwrite(ip);

	sb_start_pagefault(inode->i_sb);
	file_update_time(vma->vm_file);

	/* check if the faulting page hasn't raced with truncate */
	xfs_ilock(ip, XFS_MMAPLOCK_SHARED);
	size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
	if (vmf->pgoff >= size)
		ret = VM_FAULT_SIGBUS;
1522 1523
	else if (IS_DAX(inode))
		ret = dax_pfn_mkwrite(vma, vmf);
1524 1525
	xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
	sb_end_pagefault(inode->i_sb);
M
Matthew Wilcox 已提交
1526
	return ret;
1527

M
Matthew Wilcox 已提交
1528 1529
}

1530 1531
static const struct vm_operations_struct xfs_file_vm_ops = {
	.fault		= xfs_filemap_fault,
M
Matthew Wilcox 已提交
1532
	.pmd_fault	= xfs_filemap_pmd_fault,
1533 1534
	.map_pages	= filemap_map_pages,
	.page_mkwrite	= xfs_filemap_page_mkwrite,
1535
	.pfn_mkwrite	= xfs_filemap_pfn_mkwrite,
1536 1537 1538 1539 1540 1541 1542 1543 1544 1545
};

STATIC int
xfs_file_mmap(
	struct file	*filp,
	struct vm_area_struct *vma)
{
	file_accessed(filp);
	vma->vm_ops = &xfs_file_vm_ops;
	if (IS_DAX(file_inode(filp)))
M
Matthew Wilcox 已提交
1546
		vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
1547
	return 0;
1548 1549
}

1550
const struct file_operations xfs_file_operations = {
1551
	.llseek		= xfs_file_llseek,
A
Al Viro 已提交
1552
	.read_iter	= xfs_file_read_iter,
A
Al Viro 已提交
1553
	.write_iter	= xfs_file_write_iter,
1554
	.splice_read	= generic_file_splice_read,
A
Al Viro 已提交
1555
	.splice_write	= iter_file_splice_write,
1556
	.unlocked_ioctl	= xfs_file_ioctl,
L
Linus Torvalds 已提交
1557
#ifdef CONFIG_COMPAT
1558
	.compat_ioctl	= xfs_file_compat_ioctl,
L
Linus Torvalds 已提交
1559
#endif
1560 1561 1562 1563
	.mmap		= xfs_file_mmap,
	.open		= xfs_file_open,
	.release	= xfs_file_release,
	.fsync		= xfs_file_fsync,
1564
	.get_unmapped_area = thp_get_unmapped_area,
1565
	.fallocate	= xfs_file_fallocate,
1566 1567
	.copy_file_range = xfs_file_copy_range,
	.clone_file_range = xfs_file_clone_range,
1568
	.dedupe_file_range = xfs_file_dedupe_range,
L
Linus Torvalds 已提交
1569 1570
};

1571
const struct file_operations xfs_dir_file_operations = {
1572
	.open		= xfs_dir_open,
L
Linus Torvalds 已提交
1573
	.read		= generic_read_dir,
1574
	.iterate_shared	= xfs_file_readdir,
1575
	.llseek		= generic_file_llseek,
1576
	.unlocked_ioctl	= xfs_file_ioctl,
1577
#ifdef CONFIG_COMPAT
1578
	.compat_ioctl	= xfs_file_compat_ioctl,
1579
#endif
1580
	.fsync		= xfs_dir_fsync,
L
Linus Torvalds 已提交
1581
};