[merged mm-nonmm-stable] ocfs2-fix-races-between-hole-punching-and-aiodio.patch removed from -mm tree

[merged mm-nonmm-stable] ocfs2-fix-races-between-hole-punching-and-aiodio.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: ocfs2: fix races between hole punching and AIO+DIO
has been removed from the -mm tree.  Its filename was
     ocfs2-fix-races-between-hole-punching-and-aiodio.patch

This patch was dropped because it was merged into the mm-nonmm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Su Yue <glass.su@suse.com>
Subject: ocfs2: fix races between hole punching and AIO+DIO
Date: Mon, 8 Apr 2024 16:20:39 +0800

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
ocfs2_fallocate
 __ocfs2_change_file_space
  inode lock
  lock ip_alloc_sem
  ocfs2_remove_inode_range inode
   ocfs2_remove_btree_range
    ocfs2_remove_extent
    ^---remove the extent at cpos 78723
  ...
  unlock ip_alloc_sem
  inode unlock
                                       ocfs2_dio_end_io
                                        ocfs2_dio_end_io_write
                                         lock ip_alloc_sem
                                         ocfs2_mark_extent_written
                                          ocfs2_change_extent_flag
                                           ocfs2_search_extent_list
                                           ^---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.

Link: https://lkml.kernel.org/r/20240408082041.20925-3-glass.su@suse.com
Fixes: b25801038da5 ("ocfs2: Support xfs style space reservation ioctls")
Signed-off-by: Su Yue <glass.su@suse.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/ocfs2/file.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/ocfs2/file.c~ocfs2-fix-races-between-hole-punching-and-aiodio
+++ a/fs/ocfs2/file.c
@@ -1936,6 +1936,8 @@ static int __ocfs2_change_file_space(str
 
 	inode_lock(inode);
 
+	/* Wait all existing dio workers, newcomers will block on i_rwsem */
+	inode_dio_wait(inode);
 	/*
 	 * This prevents concurrent writes on other nodes
 	 */
_

Patches currently in -mm which might be from glass.su@suse.com are