xfs_file.c 40.1 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 <linux/dcache.h>
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#include <linux/falloc.h>
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#include <linux/pagevec.h>
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static const struct vm_operations_struct xfs_file_vm_ops;
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/*
 * Locking primitives for read and write IO paths to ensure we consistently use
 * and order the inode->i_mutex, ip->i_lock and ip->i_iolock.
 */
static inline void
xfs_rw_ilock(
	struct xfs_inode	*ip,
	int			type)
{
	if (type & XFS_IOLOCK_EXCL)
		mutex_lock(&VFS_I(ip)->i_mutex);
	xfs_ilock(ip, type);
}

static inline void
xfs_rw_iunlock(
	struct xfs_inode	*ip,
	int			type)
{
	xfs_iunlock(ip, type);
	if (type & XFS_IOLOCK_EXCL)
		mutex_unlock(&VFS_I(ip)->i_mutex);
}

static inline void
xfs_rw_ilock_demote(
	struct xfs_inode	*ip,
	int			type)
{
	xfs_ilock_demote(ip, type);
	if (type & XFS_IOLOCK_EXCL)
		mutex_unlock(&VFS_I(ip)->i_mutex);
}

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/*
 *	xfs_iozero
 *
 *	xfs_iozero clears the specified range of buffer supplied,
 *	and marks all the affected blocks as valid and modified.  If
 *	an affected block is not allocated, it will be allocated.  If
 *	an affected block is not completely overwritten, and is not
 *	valid before the operation, it will be read from disk before
 *	being partially zeroed.
 */
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int
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xfs_iozero(
	struct xfs_inode	*ip,	/* inode			*/
	loff_t			pos,	/* offset in file		*/
	size_t			count)	/* size of data to zero		*/
{
	struct page		*page;
	struct address_space	*mapping;
	int			status;

	mapping = VFS_I(ip)->i_mapping;
	do {
		unsigned offset, bytes;
		void *fsdata;

		offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
		bytes = PAGE_CACHE_SIZE - offset;
		if (bytes > count)
			bytes = count;

		status = pagecache_write_begin(NULL, mapping, pos, bytes,
					AOP_FLAG_UNINTERRUPTIBLE,
					&page, &fsdata);
		if (status)
			break;

		zero_user(page, offset, bytes);

		status = pagecache_write_end(NULL, mapping, pos, bytes, bytes,
					page, fsdata);
		WARN_ON(status <= 0); /* can't return less than zero! */
		pos += bytes;
		count -= bytes;
		status = 0;
	} while (count);

	return (-status);
}

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

	tp = xfs_trans_alloc(ip->i_mount, XFS_TRANS_WRITEID);
	error = xfs_trans_reserve(tp, &M_RES(ip->i_mount)->tr_writeid, 0, 0);
	if (error) {
		xfs_trans_cancel(tp, 0);
		return error;
	}

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

	if (!(flags & XFS_PREALLOC_INVISIBLE)) {
		ip->i_d.di_mode &= ~S_ISUID;
		if (ip->i_d.di_mode & S_IXGRP)
			ip->i_d.di_mode &= ~S_ISGID;
		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);
	return xfs_trans_commit(tp, 0);
}

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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.
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	 */
	xfs_ilock(ip, XFS_ILOCK_SHARED);
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	if (xfs_ipincount(ip)) {
		if (!datasync ||
		    (ip->i_itemp->ili_fields & ~XFS_ILOG_TIMESTAMP))
			lsn = ip->i_itemp->ili_last_lsn;
	}
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	xfs_iunlock(ip, XFS_ILOCK_SHARED);
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	if (lsn)
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		error = _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, &log_flushed);

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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_read_iter(
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	struct kiocb		*iocb,
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	struct iov_iter		*to)
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{
	struct file		*file = iocb->ki_filp;
	struct inode		*inode = file->f_mapping->host;
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	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
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	size_t			size = iov_iter_count(to);
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	ssize_t			ret = 0;
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	int			ioflags = 0;
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	xfs_fsize_t		n;
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	loff_t			pos = iocb->ki_pos;
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	XFS_STATS_INC(xs_read_calls);

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	if (unlikely(iocb->ki_flags & IOCB_DIRECT))
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		ioflags |= XFS_IO_ISDIRECT;
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	if (file->f_mode & FMODE_NOCMTIME)
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		ioflags |= XFS_IO_INVIS;
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	if ((ioflags & XFS_IO_ISDIRECT) && !IS_DAX(inode)) {
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		xfs_buftarg_t	*target =
			XFS_IS_REALTIME_INODE(ip) ?
				mp->m_rtdev_targp : mp->m_ddev_targp;
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		/* DIO must be aligned to device logical sector size */
		if ((pos | size) & target->bt_logical_sectormask) {
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			if (pos == i_size_read(inode))
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				return 0;
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			return -EINVAL;
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		}
	}

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	n = mp->m_super->s_maxbytes - pos;
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	if (n <= 0 || size == 0)
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		return 0;

	if (n < size)
		size = n;

	if (XFS_FORCED_SHUTDOWN(mp))
		return -EIO;

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	/*
	 * Locking is a bit tricky here. If we take an exclusive lock
	 * for direct IO, we effectively serialise all new concurrent
	 * read IO to this file and block it behind IO that is currently in
	 * progress because IO in progress holds the IO lock shared. We only
	 * need to hold the lock exclusive to blow away the page cache, so
	 * only take lock exclusively if the page cache needs invalidation.
	 * This allows the normal direct IO case of no page cache pages to
	 * proceeed concurrently without serialisation.
	 */
	xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
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	if ((ioflags & XFS_IO_ISDIRECT) && inode->i_mapping->nrpages) {
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		xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
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		xfs_rw_ilock(ip, XFS_IOLOCK_EXCL);

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		if (inode->i_mapping->nrpages) {
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			ret = filemap_write_and_wait_range(
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							VFS_I(ip)->i_mapping,
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							pos, pos + size - 1);
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			if (ret) {
				xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL);
				return ret;
			}
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			/*
			 * Invalidate whole pages. This can return an error if
			 * we fail to invalidate a page, but this should never
			 * happen on XFS. Warn if it does fail.
			 */
			ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping,
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					pos >> PAGE_CACHE_SHIFT,
					(pos + size - 1) >> PAGE_CACHE_SHIFT);
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			WARN_ON_ONCE(ret);
			ret = 0;
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		}
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		xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
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	}
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	trace_xfs_file_read(ip, size, pos, ioflags);
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	ret = generic_file_read_iter(iocb, to);
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	if (ret > 0)
		XFS_STATS_ADD(xs_read_bytes, ret);

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	xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
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	return ret;
}

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STATIC ssize_t
xfs_file_splice_read(
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	struct file		*infilp,
	loff_t			*ppos,
	struct pipe_inode_info	*pipe,
	size_t			count,
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	unsigned int		flags)
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{
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	struct xfs_inode	*ip = XFS_I(infilp->f_mapping->host);
	int			ioflags = 0;
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	ssize_t			ret;

	XFS_STATS_INC(xs_read_calls);
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	if (infilp->f_mode & FMODE_NOCMTIME)
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		ioflags |= XFS_IO_INVIS;
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	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
		return -EIO;

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	xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
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	trace_xfs_file_splice_read(ip, count, *ppos, ioflags);

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	/* for dax, we need to avoid the page cache */
	if (IS_DAX(VFS_I(ip)))
		ret = default_file_splice_read(infilp, ppos, pipe, count, flags);
	else
		ret = generic_file_splice_read(infilp, ppos, pipe, count, flags);
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	if (ret > 0)
		XFS_STATS_ADD(xs_read_bytes, ret);

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	xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
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	return ret;
}

/*
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 * This routine is called to handle zeroing any space in the last block of the
 * file that is beyond the EOF.  We do this since the size is being increased
 * without writing anything to that block and we don't want to read the
 * garbage on the disk.
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 */
STATIC int				/* error (positive) */
xfs_zero_last_block(
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	struct xfs_inode	*ip,
	xfs_fsize_t		offset,
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	xfs_fsize_t		isize,
	bool			*did_zeroing)
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{
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	struct xfs_mount	*mp = ip->i_mount;
	xfs_fileoff_t		last_fsb = XFS_B_TO_FSBT(mp, isize);
	int			zero_offset = XFS_B_FSB_OFFSET(mp, isize);
	int			zero_len;
	int			nimaps = 1;
	int			error = 0;
	struct xfs_bmbt_irec	imap;
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	xfs_ilock(ip, XFS_ILOCK_EXCL);
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	error = xfs_bmapi_read(ip, last_fsb, 1, &imap, &nimaps, 0);
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	xfs_iunlock(ip, XFS_ILOCK_EXCL);
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	if (error)
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		return error;
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	ASSERT(nimaps > 0);
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	/*
	 * If the block underlying isize is just a hole, then there
	 * is nothing to zero.
	 */
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	if (imap.br_startblock == HOLESTARTBLOCK)
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		return 0;

	zero_len = mp->m_sb.sb_blocksize - zero_offset;
	if (isize + zero_len > offset)
		zero_len = offset - isize;
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	*did_zeroing = true;
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	return xfs_iozero(ip, isize, zero_len);
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}

/*
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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)
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{
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	struct xfs_mount	*mp = ip->i_mount;
	xfs_fileoff_t		start_zero_fsb;
	xfs_fileoff_t		end_zero_fsb;
	xfs_fileoff_t		zero_count_fsb;
	xfs_fileoff_t		last_fsb;
	xfs_fileoff_t		zero_off;
	xfs_fsize_t		zero_len;
	int			nimaps;
	int			error = 0;
	struct xfs_bmbt_irec	imap;

	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
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	ASSERT(offset > isize);

	/*
	 * First handle zeroing the block on which isize resides.
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	 *
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	 * We only zero a part of that block so it is handled specially.
	 */
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	if (XFS_B_FSB_OFFSET(mp, isize) != 0) {
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		error = xfs_zero_last_block(ip, offset, isize, did_zeroing);
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		if (error)
			return error;
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	}

	/*
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	 * Calculate the range between the new size and the old where blocks
	 * needing to be zeroed may exist.
	 *
	 * To get the block where the last byte in the file currently resides,
	 * we need to subtract one from the size and truncate back to a block
	 * boundary.  We subtract 1 in case the size is exactly on a block
	 * boundary.
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	 */
	last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
	start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
	end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
	ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
	if (last_fsb == end_zero_fsb) {
		/*
		 * The size was only incremented on its last block.
		 * We took care of that above, so just return.
		 */
		return 0;
	}

	ASSERT(start_zero_fsb <= end_zero_fsb);
	while (start_zero_fsb <= end_zero_fsb) {
		nimaps = 1;
		zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
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		xfs_ilock(ip, XFS_ILOCK_EXCL);
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		error = xfs_bmapi_read(ip, start_zero_fsb, zero_count_fsb,
					  &imap, &nimaps, 0);
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		xfs_iunlock(ip, XFS_ILOCK_EXCL);
		if (error)
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			return error;
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		ASSERT(nimaps > 0);

		if (imap.br_state == XFS_EXT_UNWRITTEN ||
		    imap.br_startblock == HOLESTARTBLOCK) {
			start_zero_fsb = imap.br_startoff + imap.br_blockcount;
			ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
			continue;
		}

		/*
		 * There are blocks we need to zero.
		 */
		zero_off = XFS_FSB_TO_B(mp, start_zero_fsb);
		zero_len = XFS_FSB_TO_B(mp, imap.br_blockcount);

		if ((zero_off + zero_len) > offset)
			zero_len = offset - zero_off;

		error = xfs_iozero(ip, zero_off, zero_len);
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		if (error)
			return error;
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		*did_zeroing = true;
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		start_zero_fsb = imap.br_startoff + imap.br_blockcount;
		ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
	}

	return 0;
}

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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;
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	size_t			count = iov_iter_count(from);
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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, true);
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	if (error)
		return error;

570 571 572
	/*
	 * 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
573
	 * write.  If zeroing is needed and we are currently holding the
574 575
	 * iolock shared, we need to update it to exclusive which implies
	 * having to redo all checks before.
576 577 578 579 580 581 582 583
	 *
	 * 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.
584
	 */
585
	spin_lock(&ip->i_flags_lock);
586
	if (iocb->ki_pos > i_size_read(inode)) {
587 588
		bool	zero = false;

589
		spin_unlock(&ip->i_flags_lock);
590
		if (*iolock == XFS_IOLOCK_SHARED) {
591
			xfs_rw_iunlock(ip, *iolock);
592
			*iolock = XFS_IOLOCK_EXCL;
593
			xfs_rw_ilock(ip, *iolock);
594
			iov_iter_reexpand(from, count);
595 596 597 598 599 600 601 602 603 604

			/*
			 * 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);
605 606
			goto restart;
		}
607
		error = xfs_zero_eof(ip, iocb->ki_pos, i_size_read(inode), &zero);
608 609
		if (error)
			return error;
610 611
	} else
		spin_unlock(&ip->i_flags_lock);
612

C
Christoph Hellwig 已提交
613 614 615 616 617 618
	/*
	 * 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.
	 */
619 620 621 622 623
	if (likely(!(file->f_mode & FMODE_NOCMTIME))) {
		error = file_update_time(file);
		if (error)
			return error;
	}
C
Christoph Hellwig 已提交
624

625 626 627 628 629 630 631 632
	/*
	 * 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.
	 */
	return file_remove_suid(file);
}

633 634 635 636
/*
 * xfs_file_dio_aio_write - handle direct IO writes
 *
 * Lock the inode appropriately to prepare for and issue a direct IO write.
637
 * By separating it from the buffered write path we remove all the tricky to
638 639
 * follow locking changes and looping.
 *
640 641 642 643 644 645 646 647 648 649 650 651 652
 * 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
C
Christoph Hellwig 已提交
653
 * hitting it with a big hammer (i.e. inode_dio_wait()).
654
 *
655 656 657 658 659 660
 * 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,
661
	struct iov_iter		*from)
662 663 664 665 666 667 668
{
	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;
669
	int			unaligned_io = 0;
670
	int			iolock;
671 672
	size_t			count = iov_iter_count(from);
	loff_t			pos = iocb->ki_pos;
673 674
	loff_t			end;
	struct iov_iter		data;
675 676 677
	struct xfs_buftarg	*target = XFS_IS_REALTIME_INODE(ip) ?
					mp->m_rtdev_targp : mp->m_ddev_targp;

678
	/* DIO must be aligned to device logical sector size */
679
	if (!IS_DAX(inode) && ((pos | count) & target->bt_logical_sectormask))
E
Eric Sandeen 已提交
680
		return -EINVAL;
681

682
	/* "unaligned" here means not aligned to a filesystem block */
683 684 685
	if ((pos & mp->m_blockmask) || ((pos + count) & mp->m_blockmask))
		unaligned_io = 1;

686 687 688 689 690 691 692 693
	/*
	 * We don't need to take an exclusive lock unless there page cache needs
	 * to be invalidated or unaligned IO is being executed. 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.
	 */
	if (unaligned_io || mapping->nrpages)
694
		iolock = XFS_IOLOCK_EXCL;
695
	else
696 697
		iolock = XFS_IOLOCK_SHARED;
	xfs_rw_ilock(ip, iolock);
698 699 700 701 702 703

	/*
	 * Recheck if there are cached pages that need invalidate after we got
	 * the iolock to protect against other threads adding new pages while
	 * we were waiting for the iolock.
	 */
704 705 706 707
	if (mapping->nrpages && iolock == XFS_IOLOCK_SHARED) {
		xfs_rw_iunlock(ip, iolock);
		iolock = XFS_IOLOCK_EXCL;
		xfs_rw_ilock(ip, iolock);
708
	}
709

710
	ret = xfs_file_aio_write_checks(iocb, from, &iolock);
711
	if (ret)
712
		goto out;
713 714
	count = iov_iter_count(from);
	pos = iocb->ki_pos;
715
	end = pos + count - 1;
716 717

	if (mapping->nrpages) {
718
		ret = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
719
						   pos, end);
720
		if (ret)
721
			goto out;
722 723 724 725 726 727
		/*
		 * Invalidate whole pages. This can return an error if
		 * we fail to invalidate a page, but this should never
		 * happen on XFS. Warn if it does fail.
		 */
		ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping,
728
					pos >> PAGE_CACHE_SHIFT,
729
					end >> PAGE_CACHE_SHIFT);
730 731
		WARN_ON_ONCE(ret);
		ret = 0;
732 733
	}

734 735 736 737 738
	/*
	 * If we are doing unaligned IO, wait for all other IO to drain,
	 * otherwise demote the lock if we had to flush cached pages
	 */
	if (unaligned_io)
C
Christoph Hellwig 已提交
739
		inode_dio_wait(inode);
740
	else if (iolock == XFS_IOLOCK_EXCL) {
741
		xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
742
		iolock = XFS_IOLOCK_SHARED;
743 744 745 746
	}

	trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0);

747
	data = *from;
748
	ret = mapping->a_ops->direct_IO(iocb, &data, pos);
749 750 751 752 753 754 755 756 757 758 759 760 761

	/* see generic_file_direct_write() for why this is necessary */
	if (mapping->nrpages) {
		invalidate_inode_pages2_range(mapping,
					      pos >> PAGE_CACHE_SHIFT,
					      end >> PAGE_CACHE_SHIFT);
	}

	if (ret > 0) {
		pos += ret;
		iov_iter_advance(from, ret);
		iocb->ki_pos = pos;
	}
762 763 764
out:
	xfs_rw_iunlock(ip, iolock);

765 766 767 768 769
	/*
	 * No fallback to buffered IO on errors for XFS. DAX can result in
	 * partial writes, but direct IO will either complete fully or fail.
	 */
	ASSERT(ret < 0 || ret == count || IS_DAX(VFS_I(ip)));
770 771 772
	return ret;
}

773
STATIC ssize_t
774
xfs_file_buffered_aio_write(
775
	struct kiocb		*iocb,
776
	struct iov_iter		*from)
777 778 779 780
{
	struct file		*file = iocb->ki_filp;
	struct address_space	*mapping = file->f_mapping;
	struct inode		*inode = mapping->host;
781
	struct xfs_inode	*ip = XFS_I(inode);
782 783
	ssize_t			ret;
	int			enospc = 0;
784
	int			iolock = XFS_IOLOCK_EXCL;
785

786
	xfs_rw_ilock(ip, iolock);
787

788
	ret = xfs_file_aio_write_checks(iocb, from, &iolock);
789
	if (ret)
790
		goto out;
791 792

	/* We can write back this queue in page reclaim */
793
	current->backing_dev_info = inode_to_bdi(inode);
794 795

write_retry:
796 797 798
	trace_xfs_file_buffered_write(ip, iov_iter_count(from),
				      iocb->ki_pos, 0);
	ret = generic_perform_write(file, from, iocb->ki_pos);
799
	if (likely(ret >= 0))
800
		iocb->ki_pos += ret;
801

802
	/*
803 804 805 806 807 808 809
	 * 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.
810
	 */
811 812 813 814 815 816 817
	if (ret == -EDQUOT && !enospc) {
		enospc = xfs_inode_free_quota_eofblocks(ip);
		if (enospc)
			goto write_retry;
	} else if (ret == -ENOSPC && !enospc) {
		struct xfs_eofblocks eofb = {0};

818
		enospc = 1;
D
Dave Chinner 已提交
819
		xfs_flush_inodes(ip->i_mount);
820 821 822
		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
823
		goto write_retry;
824
	}
825

826
	current->backing_dev_info = NULL;
827 828
out:
	xfs_rw_iunlock(ip, iolock);
829 830 831 832
	return ret;
}

STATIC ssize_t
A
Al Viro 已提交
833
xfs_file_write_iter(
834
	struct kiocb		*iocb,
A
Al Viro 已提交
835
	struct iov_iter		*from)
836 837 838 839 840 841
{
	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
842
	size_t			ocount = iov_iter_count(from);
843 844 845 846 847 848

	XFS_STATS_INC(xs_write_calls);

	if (ocount == 0)
		return 0;

A
Al Viro 已提交
849 850
	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
		return -EIO;
851

852
	if ((iocb->ki_flags & IOCB_DIRECT) || IS_DAX(inode))
A
Al Viro 已提交
853
		ret = xfs_file_dio_aio_write(iocb, from);
854
	else
A
Al Viro 已提交
855
		ret = xfs_file_buffered_aio_write(iocb, from);
856

857 858
	if (ret > 0) {
		ssize_t err;
859

860
		XFS_STATS_ADD(xs_write_bytes, ret);
861

862
		/* Handle various SYNC-type writes */
863
		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
864 865
		if (err < 0)
			ret = err;
866
	}
867
	return ret;
868 869
}

870 871 872 873 874
#define	XFS_FALLOC_FL_SUPPORTED						\
		(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |		\
		 FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |	\
		 FALLOC_FL_INSERT_RANGE)

875 876
STATIC long
xfs_file_fallocate(
877 878 879 880
	struct file		*file,
	int			mode,
	loff_t			offset,
	loff_t			len)
881
{
882 883 884
	struct inode		*inode = file_inode(file);
	struct xfs_inode	*ip = XFS_I(inode);
	long			error;
885
	enum xfs_prealloc_flags	flags = 0;
886
	uint			iolock = XFS_IOLOCK_EXCL;
887
	loff_t			new_size = 0;
888
	bool			do_file_insert = 0;
889

890 891
	if (!S_ISREG(inode->i_mode))
		return -EINVAL;
892
	if (mode & ~XFS_FALLOC_FL_SUPPORTED)
893 894
		return -EOPNOTSUPP;

895
	xfs_ilock(ip, iolock);
896
	error = xfs_break_layouts(inode, &iolock, false);
897 898 899
	if (error)
		goto out_unlock;

900 901 902
	xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
	iolock |= XFS_MMAPLOCK_EXCL;

903 904 905 906
	if (mode & FALLOC_FL_PUNCH_HOLE) {
		error = xfs_free_file_space(ip, offset, len);
		if (error)
			goto out_unlock;
907 908 909 910
	} 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
911
			error = -EINVAL;
912 913 914
			goto out_unlock;
		}

915 916 917 918 919
		/*
		 * 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
920
			error = -EINVAL;
921 922 923
			goto out_unlock;
		}

924 925 926 927 928
		new_size = i_size_read(inode) - len;

		error = xfs_collapse_file_space(ip, offset, len);
		if (error)
			goto out_unlock;
929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949
	} 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;
950
	} else {
951 952
		flags |= XFS_PREALLOC_SET;

953 954 955
		if (!(mode & FALLOC_FL_KEEP_SIZE) &&
		    offset + len > i_size_read(inode)) {
			new_size = offset + len;
D
Dave Chinner 已提交
956
			error = inode_newsize_ok(inode, new_size);
957 958 959
			if (error)
				goto out_unlock;
		}
960

961 962 963 964 965
		if (mode & FALLOC_FL_ZERO_RANGE)
			error = xfs_zero_file_space(ip, offset, len);
		else
			error = xfs_alloc_file_space(ip, offset, len,
						     XFS_BMAPI_PREALLOC);
966 967 968 969
		if (error)
			goto out_unlock;
	}

970
	if (file->f_flags & O_DSYNC)
971 972 973
		flags |= XFS_PREALLOC_SYNC;

	error = xfs_update_prealloc_flags(ip, flags);
974 975 976 977 978 979 980 981 982
	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;
983
		error = xfs_setattr_size(ip, &iattr);
984 985
		if (error)
			goto out_unlock;
986 987
	}

988 989 990 991 992 993 994 995 996
	/*
	 * 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);

997
out_unlock:
998
	xfs_iunlock(ip, iolock);
D
Dave Chinner 已提交
999
	return error;
1000 1001 1002
}


L
Linus Torvalds 已提交
1003
STATIC int
1004
xfs_file_open(
L
Linus Torvalds 已提交
1005
	struct inode	*inode,
1006
	struct file	*file)
L
Linus Torvalds 已提交
1007
{
1008
	if (!(file->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
L
Linus Torvalds 已提交
1009
		return -EFBIG;
1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031
	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.
	 */
1032
	mode = xfs_ilock_data_map_shared(ip);
1033
	if (ip->i_d.di_nextents > 0)
1034
		xfs_dir3_data_readahead(ip, 0, -1);
1035 1036
	xfs_iunlock(ip, mode);
	return 0;
L
Linus Torvalds 已提交
1037 1038 1039
}

STATIC int
1040
xfs_file_release(
L
Linus Torvalds 已提交
1041 1042 1043
	struct inode	*inode,
	struct file	*filp)
{
D
Dave Chinner 已提交
1044
	return xfs_release(XFS_I(inode));
L
Linus Torvalds 已提交
1045 1046 1047
}

STATIC int
1048
xfs_file_readdir(
A
Al Viro 已提交
1049 1050
	struct file	*file,
	struct dir_context *ctx)
L
Linus Torvalds 已提交
1051
{
A
Al Viro 已提交
1052
	struct inode	*inode = file_inode(file);
1053
	xfs_inode_t	*ip = XFS_I(inode);
C
Christoph Hellwig 已提交
1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065
	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
1066
	 * buffer size.  For now we use the current glibc buffer size.
C
Christoph Hellwig 已提交
1067
	 */
E
Eric Sandeen 已提交
1068
	bufsize = (size_t)min_t(loff_t, 32768, ip->i_d.di_size);
C
Christoph Hellwig 已提交
1069

1070
	return xfs_readdir(ip, ctx, bufsize);
L
Linus Torvalds 已提交
1071 1072
}

1073 1074
/*
 * This type is designed to indicate the type of offset we would like
1075
 * to search from page cache for xfs_seek_hole_data().
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
 */
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
1132
 * type for xfs_seek_hole_data().
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 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290
 *
 * 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);

	index = startoff >> PAGE_CACHE_SHIFT;
	endoff = XFS_FSB_TO_B(mp, map->br_startoff + map->br_blockcount);
	end = endoff >> PAGE_CACHE_SHIFT;
	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;
}

1291
STATIC loff_t
1292
xfs_seek_hole_data(
1293
	struct file		*file,
1294 1295
	loff_t			start,
	int			whence)
1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306
{
	struct inode		*inode = file->f_mapping->host;
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	loff_t			uninitialized_var(offset);
	xfs_fsize_t		isize;
	xfs_fileoff_t		fsbno;
	xfs_filblks_t		end;
	uint			lock;
	int			error;

1307 1308 1309
	if (XFS_FORCED_SHUTDOWN(mp))
		return -EIO;

1310
	lock = xfs_ilock_data_map_shared(ip);
1311 1312 1313

	isize = i_size_read(inode);
	if (start >= isize) {
D
Dave Chinner 已提交
1314
		error = -ENXIO;
1315 1316 1317 1318 1319 1320 1321
		goto out_unlock;
	}

	/*
	 * Try to read extents from the first block indicated
	 * by fsbno to the end block of the file.
	 */
1322
	fsbno = XFS_B_TO_FSBT(mp, start);
1323
	end = XFS_B_TO_FSB(mp, isize);
1324

1325 1326 1327 1328
	for (;;) {
		struct xfs_bmbt_irec	map[2];
		int			nmap = 2;
		unsigned int		i;
1329

1330 1331 1332 1333
		error = xfs_bmapi_read(ip, fsbno, end - fsbno, map, &nmap,
				       XFS_BMAPI_ENTIRE);
		if (error)
			goto out_unlock;
1334

1335 1336
		/* No extents at given offset, must be beyond EOF */
		if (nmap == 0) {
D
Dave Chinner 已提交
1337
			error = -ENXIO;
1338 1339 1340 1341 1342 1343 1344
			goto out_unlock;
		}

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

1345 1346 1347 1348 1349 1350 1351 1352 1353 1354
			/* 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))))
1355 1356 1357
				goto out;

			/*
1358 1359
			 * Landed in an unwritten extent, try to search
			 * for hole or data from page cache.
1360 1361 1362
			 */
			if (map[i].br_state == XFS_EXT_UNWRITTEN) {
				if (xfs_find_get_desired_pgoff(inode, &map[i],
1363 1364
				      whence == SEEK_HOLE ? HOLE_OFF : DATA_OFF,
							&offset))
1365 1366 1367 1368 1369
					goto out;
			}
		}

		/*
1370 1371
		 * 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.
1372
		 */
1373
		if (nmap == 1) {
1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386
			/*
			 * 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) {
				offset = isize;
				break;
			}
			/*
			 * If we were looking for data, it's nowhere to be found
			 */
			ASSERT(whence == SEEK_DATA);
D
Dave Chinner 已提交
1387
			error = -ENXIO;
1388 1389 1390
			goto out_unlock;
		}

1391 1392 1393 1394
		ASSERT(i > 1);

		/*
		 * Nothing was found, proceed to the next round of search
1395
		 * if the next reading offset is not at or beyond EOF.
1396 1397 1398 1399
		 */
		fsbno = map[i - 1].br_startoff + map[i - 1].br_blockcount;
		start = XFS_FSB_TO_B(mp, fsbno);
		if (start >= isize) {
1400 1401 1402 1403 1404
			if (whence == SEEK_HOLE) {
				offset = isize;
				break;
			}
			ASSERT(whence == SEEK_DATA);
D
Dave Chinner 已提交
1405
			error = -ENXIO;
1406 1407
			goto out_unlock;
		}
1408 1409
	}

1410 1411
out:
	/*
1412
	 * If at this point we have found the hole we wanted, the returned
1413
	 * offset may be bigger than the file size as it may be aligned to
1414
	 * page boundary for unwritten extents.  We need to deal with this
1415 1416
	 * situation in particular.
	 */
1417 1418
	if (whence == SEEK_HOLE)
		offset = min_t(loff_t, offset, isize);
J
Jie Liu 已提交
1419
	offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
1420 1421

out_unlock:
1422
	xfs_iunlock(ip, lock);
1423 1424

	if (error)
D
Dave Chinner 已提交
1425
		return error;
1426 1427 1428 1429 1430 1431 1432
	return offset;
}

STATIC loff_t
xfs_file_llseek(
	struct file	*file,
	loff_t		offset,
1433
	int		whence)
1434
{
1435
	switch (whence) {
1436 1437 1438
	case SEEK_END:
	case SEEK_CUR:
	case SEEK_SET:
1439
		return generic_file_llseek(file, offset, whence);
1440
	case SEEK_HOLE:
1441
	case SEEK_DATA:
1442
		return xfs_seek_hole_data(file, offset, whence);
1443 1444 1445 1446 1447
	default:
		return -EINVAL;
	}
}

1448 1449 1450 1451 1452
/*
 * Locking for serialisation of IO during page faults. This results in a lock
 * ordering of:
 *
 * mmap_sem (MM)
1453 1454 1455 1456
 *   sb_start_pagefault(vfs, freeze)
 *     i_mmap_lock (XFS - truncate serialisation)
 *       page_lock (MM)
 *         i_lock (XFS - extent map serialisation)
1457 1458
 */

1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469
/*
 * 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.
 */
STATIC int
xfs_filemap_page_mkwrite(
	struct vm_area_struct	*vma,
	struct vm_fault		*vmf)
{
1470
	struct inode		*inode = file_inode(vma->vm_file);
1471
	int			ret;
1472

1473
	trace_xfs_filemap_page_mkwrite(XFS_I(inode));
1474

1475
	sb_start_pagefault(inode->i_sb);
1476
	file_update_time(vma->vm_file);
1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499
	xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);

	if (IS_DAX(inode)) {
		ret = __dax_mkwrite(vma, vmf, xfs_get_blocks_direct,
				    xfs_end_io_dax_write);
	} else {
		ret = __block_page_mkwrite(vma, vmf, xfs_get_blocks);
		ret = block_page_mkwrite_return(ret);
	}

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

	return ret;
}

STATIC int
xfs_filemap_fault(
	struct vm_area_struct	*vma,
	struct vm_fault		*vmf)
{
	struct xfs_inode	*ip = XFS_I(file_inode(vma->vm_file));
	int			ret;
1500

1501 1502 1503 1504 1505
	trace_xfs_filemap_fault(ip);

	/* DAX can shortcut the normal fault path on write faults! */
	if ((vmf->flags & FAULT_FLAG_WRITE) && IS_DAX(VFS_I(ip)))
		return xfs_filemap_page_mkwrite(vma, vmf);
1506

1507 1508
	xfs_ilock(ip, XFS_MMAPLOCK_SHARED);
	ret = filemap_fault(vma, vmf);
1509 1510
	xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);

1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529
	return ret;
}

static const struct vm_operations_struct xfs_file_vm_ops = {
	.fault		= xfs_filemap_fault,
	.map_pages	= filemap_map_pages,
	.page_mkwrite	= xfs_filemap_page_mkwrite,
};

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)))
		vma->vm_flags |= VM_MIXEDMAP;
	return 0;
1530 1531
}

1532
const struct file_operations xfs_file_operations = {
1533
	.llseek		= xfs_file_llseek,
A
Al Viro 已提交
1534
	.read_iter	= xfs_file_read_iter,
A
Al Viro 已提交
1535
	.write_iter	= xfs_file_write_iter,
1536
	.splice_read	= xfs_file_splice_read,
A
Al Viro 已提交
1537
	.splice_write	= iter_file_splice_write,
1538
	.unlocked_ioctl	= xfs_file_ioctl,
L
Linus Torvalds 已提交
1539
#ifdef CONFIG_COMPAT
1540
	.compat_ioctl	= xfs_file_compat_ioctl,
L
Linus Torvalds 已提交
1541
#endif
1542 1543 1544 1545
	.mmap		= xfs_file_mmap,
	.open		= xfs_file_open,
	.release	= xfs_file_release,
	.fsync		= xfs_file_fsync,
1546
	.fallocate	= xfs_file_fallocate,
L
Linus Torvalds 已提交
1547 1548
};

1549
const struct file_operations xfs_dir_file_operations = {
1550
	.open		= xfs_dir_open,
L
Linus Torvalds 已提交
1551
	.read		= generic_read_dir,
A
Al Viro 已提交
1552
	.iterate	= xfs_file_readdir,
1553
	.llseek		= generic_file_llseek,
1554
	.unlocked_ioctl	= xfs_file_ioctl,
1555
#ifdef CONFIG_COMPAT
1556
	.compat_ioctl	= xfs_file_compat_ioctl,
1557
#endif
1558
	.fsync		= xfs_dir_fsync,
L
Linus Torvalds 已提交
1559
};