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[v3,2/4] ocfs2: fix races between hole punching and AIO+DIO

Message ID 20240408082041.20925-3-glass.su@suse.com (mailing list archive)
State New
Headers show
Series ocfs2 bugs fixes exposed by fstests | expand

Commit Message

Su Yue April 8, 2024, 8:20 a.m. UTC
After commit "ocfs2: return real error code in ocfs2_dio_wr_get_block",
fstests/generic/300 become from always failed to sometimes failed:

[  473.293420 ] run fstests generic/300

[  475.296983 ] JBD2: Ignoring recovery information on journal
[  475.302473 ] ocfs2: Mounting device (253,1) on (node local, slot 0)
with ordered data mode.
[  494.290998 ] OCFS2: ERROR (device dm-1): ocfs2_change_extent_flag:
Owner 5668 has an extent at cpos 78723 which can no longer be found
[  494.291609 ] On-disk corruption discovered. Please run fsck.ocfs2
once the filesystem is unmounted.
[  494.292018 ] OCFS2: File system is now read-only.
[  494.292224 ] (kworker/19:11,2628,19):ocfs2_mark_extent_written:5272
ERROR: status = -30
[  494.292602 ] (kworker/19:11,2628,19):ocfs2_dio_end_io_write:2374
ERROR: status = -3
fio: io_u error on file /mnt/scratch/racer: Read-only file system: write
offset=460849152, buflen=131072

In __blockdev_direct_IO, ocfs2_dio_wr_get_block is called to add
unwritten extents to a list. extents are also inserted into extent tree
in ocfs2_write_begin_nolock. Then another thread call fallocate to
puch a hole at one of the unwritten extent. The extent at cpos was
removed by ocfs2_remove_extent(). At end io worker thread,
ocfs2_search_extent_list found there is no such extent at the cpos.

    T1                        T2                T3
                              inode lock
                                insert extents
                              inode unlock
  inode lock
  lock ip_alloc_sem
  ocfs2_remove_inode_range inode
    ^---remove the extent at cpos 78723
  unlock ip_alloc_sem
  inode unlock
                                         lock ip_alloc_sem
                                           ^---failed to find extent
                                          unlock ip_alloc_sem

In most filesystems, fallocate is not compatible with racing with
AIO+DIO, so fix it by adding to wait for all dio before
fallocate/punch_hole like ext4.

Fixes: b25801038da5 ("ocfs2: Support xfs style space reservation ioctls")
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Su Yue <glass.su@suse.com>
 fs/ocfs2/file.c | 2 ++
 1 file changed, 2 insertions(+)
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diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 0da8e7bd3261..ccc57038a977 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1936,6 +1936,8 @@  static int __ocfs2_change_file_space(struct file *file, struct inode *inode,
+	/* Wait all existing dio workers, newcomers will block on i_rwsem */
+	inode_dio_wait(inode);
 	 * This prevents concurrent writes on other nodes