On 2023/3/29 9:02, Darrick J. Wong wrote:
On Tue, Mar 28, 2023 at 10:21:29PM +0800, Ye Bin wrote:
From: Ye Bin <yebin10@xxxxxxxxxx>
There's issue as follows:
XFS: Assertion failed: (bmv->bmv_iflags & BMV_IF_DELALLOC) != 0, file: fs/xfs/xfs_bmap_util.c, line: 329
------------[ cut here ]------------
kernel BUG at fs/xfs/xfs_message.c:102!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 14612 Comm: xfs_io Not tainted 6.3.0-rc2-next-20230315-00006-g2729d23ddb3b-dirty #422
RIP: 0010:assfail+0x96/0xa0
RSP: 0018:ffffc9000fa178c0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff888179a18000
RDX: 0000000000000000 RSI: ffff888179a18000 RDI: 0000000000000002
RBP: 0000000000000000 R08: ffffffff8321aab6 R09: 0000000000000000
R10: 0000000000000001 R11: ffffed1105f85139 R12: ffffffff8aacc4c0
R13: 0000000000000149 R14: ffff888269f58000 R15: 000000000000000c
FS: 00007f42f27a4740(0000) GS:ffff88882fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000b92388 CR3: 000000024f006000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
xfs_getbmap+0x1a5b/0x1e40
xfs_ioc_getbmap+0x1fd/0x5b0
xfs_file_ioctl+0x2cb/0x1d50
__x64_sys_ioctl+0x197/0x210
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Above issue may happen as follows:
ThreadA ThreadB
do_shared_fault
__do_fault
xfs_filemap_fault
__xfs_filemap_fault
filemap_fault
xfs_ioc_getbmap -> Without BMV_IF_DELALLOC flag
xfs_getbmap
xfs_ilock(ip, XFS_IOLOCK_SHARED);
filemap_write_and_wait
do_page_mkwrite
xfs_filemap_page_mkwrite
__xfs_filemap_fault
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
iomap_page_mkwrite
...
xfs_buffered_write_iomap_begin
xfs_bmapi_reserve_delalloc -> Allocate delay extent
xfs_ilock_data_map_shared(ip)
xfs_getbmap_report_one
ASSERT((bmv->bmv_iflags & BMV_IF_DELALLOC) != 0)
-> trigger BUG_ON
As xfs_filemap_page_mkwrite() only hold XFS_MMAPLOCK_SHARED lock, there's
small window mkwrite can produce delay extent after file write in xfs_getbmap().
To solve above issue, just skip delalloc extents.
Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
---
fs/xfs/xfs_bmap_util.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index a09dd2606479..d2a109ceb922 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -322,7 +322,8 @@ xfs_getbmap_report_one(
* extents.
*/
if (got->br_startoff < XFS_B_TO_FSB(ip->i_mount, XFS_ISIZE(ip)))
- ASSERT((bmv->bmv_iflags & BMV_IF_DELALLOC) != 0);
+ if (!(bmv->bmv_iflags & BMV_IF_DELALLOC))
+ return 0;
Why only hide the delalloc mapping if it's below EOF?
--D
There should be no concurrency issues with normal buffer writes. But
since we need
to skip here, we won't make any distinction. I will send another version.
p->bmv_oflags |= BMV_OF_DELALLOC;
p->bmv_block = -2;
--
2.31.1
.
