linux-stable/fs/xfs/xfs_iomap.h
Eryu Guan ee70daaba8 xfs: update i_size after unwritten conversion in dio completion
Since commit d531d91d69 ("xfs: always use unwritten extents for
direct I/O writes"), we start allocating unwritten extents for all
direct writes to allow appending aio in XFS.

But for dio writes that could extend file size we update the in-core
inode size first, then convert the unwritten extents to real
allocations at dio completion time in xfs_dio_write_end_io(). Thus a
racing direct read could see the new i_size and find the unwritten
extents first and read zeros instead of actual data, if the direct
writer also takes a shared iolock.

Fix it by updating the in-core inode size after the unwritten extent
conversion. To do this, introduce a new boolean argument to
xfs_iomap_write_unwritten() to tell if we want to update in-core
i_size or not.

Suggested-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-09-26 10:55:19 -07:00

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C

/*
* Copyright (c) 2003-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* 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.
*
* 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
*/
#ifndef __XFS_IOMAP_H__
#define __XFS_IOMAP_H__
#include <linux/iomap.h>
struct xfs_inode;
struct xfs_bmbt_irec;
int xfs_iomap_write_direct(struct xfs_inode *, xfs_off_t, size_t,
struct xfs_bmbt_irec *, int);
int xfs_iomap_write_allocate(struct xfs_inode *, int, xfs_off_t,
struct xfs_bmbt_irec *);
int xfs_iomap_write_unwritten(struct xfs_inode *, xfs_off_t, xfs_off_t, bool);
void xfs_bmbt_to_iomap(struct xfs_inode *, struct iomap *,
struct xfs_bmbt_irec *);
xfs_extlen_t xfs_eof_alignment(struct xfs_inode *ip, xfs_extlen_t extsize);
static inline xfs_filblks_t
xfs_aligned_fsb_count(
xfs_fileoff_t offset_fsb,
xfs_filblks_t count_fsb,
xfs_extlen_t extsz)
{
if (extsz) {
xfs_extlen_t align;
align = do_mod(offset_fsb, extsz);
if (align)
count_fsb += align;
align = do_mod(count_fsb, extsz);
if (align)
count_fsb += extsz - align;
}
return count_fsb;
}
extern const struct iomap_ops xfs_iomap_ops;
extern const struct iomap_ops xfs_xattr_iomap_ops;
#endif /* __XFS_IOMAP_H__*/