xfs: fix BUG_ON in xfs_getbmap()
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@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>