The patch titled
Subject: ocfs2: fix races between hole punching and AIO+DIO
has been added to the -mm mm-nonmm-unstable branch. Its filename is
ocfs2-fix-races-between-hole-punching-and-aiodio.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ocfs2-fix-races-between-hole-punching-and-aiodio.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Su Yue <glass.su@xxxxxxxx>
Subject: ocfs2: fix races between hole punching and AIO+DIO
Date: Tue, 2 Apr 2024 09:46:49 +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/20240402014651.13723-3-glass.su@xxxxxxxx
Signed-off-by: Su Yue <glass.su@xxxxxxxx>
Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Cc: Changwei Ge <gechangwei@xxxxxxx>
Cc: Gang He <ghe@xxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Jun Piao <piaojun@xxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Mark Fasheh <mark@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxx are
ocfs2-update-inode-ctime-in-ocfs2_fileattr_set.patch
ocfs2-return-real-error-code-in-ocfs2_dio_wr_get_block.patch
ocfs2-fix-races-between-hole-punching-and-aiodio.patch
ocfs2-update-inode-fsync-transaction-id-in-ocfs2_unlink-and-ocfs2_link.patch
ocfs2-use-coarse-time-for-new-created-files.patch
