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xfs: update i_size after unwritten conversion in dio completion

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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>
This commit is contained in:
Eryu Guan
2017-09-21 11:26:18 -07:00
committed by Darrick J. Wong
parent 546e7be824
commit ee70daaba8
5 changed files with 28 additions and 19 deletions
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2
fs/xfs/xfs_pnfs.c
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@@ -274,7 +274,7 @@ xfs_fs_commit_blocks(
(end - 1) >> PAGE_SHIFT);
WARN_ON_ONCE(error);
error = xfs_iomap_write_unwritten(ip, start, length);
error = xfs_iomap_write_unwritten(ip, start, length, false);
if (error)
goto out_drop_iolock;
}