WSL2-Linux-Kernel/fs/ocfs2
Wengang Wang 8a8ad1c2f6 ocfs2: refcount: take rw_lock in ocfs2_reflink
This patch tries to fix this crash:

 #5 [ffff88003c1cd690] do_invalid_op at ffffffff810166d5
 #6 [ffff88003c1cd730] invalid_op at ffffffff8159b2de
    [exception RIP: ocfs2_direct_IO_get_blocks+359]
    RIP: ffffffffa05dfa27  RSP: ffff88003c1cd7e8  RFLAGS: 00010202
    RAX: 0000000000000000  RBX: ffff88003c1cdaa8  RCX: 0000000000000000
    RDX: 000000000000000c  RSI: ffff880027a95000  RDI: ffff88003c79b540
    RBP: ffff88003c1cd858   R8: 0000000000000000   R9: ffffffff815f6ba0
    R10: 00000000000001c9  R11: 00000000000001c9  R12: ffff88002d271500
    R13: 0000000000000001  R14: 0000000000000000  R15: 0000000000001000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #7 [ffff88003c1cd860] do_direct_IO at ffffffff811cd31b
 #8 [ffff88003c1cd950] direct_IO_iovec at ffffffff811cde9c
 #9 [ffff88003c1cd9b0] do_blockdev_direct_IO at ffffffff811ce764
#10 [ffff88003c1cdb80] __blockdev_direct_IO at ffffffff811ce7cc
#11 [ffff88003c1cdbb0] ocfs2_direct_IO at ffffffffa05df756 [ocfs2]
#12 [ffff88003c1cdbe0] generic_file_direct_write_iter at ffffffff8112f935
#13 [ffff88003c1cdc40] ocfs2_file_write_iter at ffffffffa0600ccc [ocfs2]
#14 [ffff88003c1cdd50] do_aio_write at ffffffff8119126c
#15 [ffff88003c1cddc0] aio_rw_vect_retry at ffffffff811d9bb4
#16 [ffff88003c1cddf0] aio_run_iocb at ffffffff811db880
#17 [ffff88003c1cde30] io_submit_one at ffffffff811dc238
#18 [ffff88003c1cde80] do_io_submit at ffffffff811dc437
#19 [ffff88003c1cdf70] sys_io_submit at ffffffff811dc530
#20 [ffff88003c1cdf80] system_call_fastpath at ffffffff8159a159

It crashes at
        BUG_ON(create && (ext_flags & OCFS2_EXT_REFCOUNTED));
in ocfs2_direct_IO_get_blocks.

ocfs2_direct_IO_get_blocks is expecting the OCFS2_EXT_REFCOUNTED be removed in
ocfs2_prepare_inode_for_write() if it was there. But no cluster lock is taken
during the time before (or inside) ocfs2_prepare_inode_for_write() and after
ocfs2_direct_IO_get_blocks().

It can happen in this case:

Node A(which crashes)				Node B
------------------------                 ---------------------------
ocfs2_file_aio_write
  ocfs2_prepare_inode_for_write
    ocfs2_inode_lock
    ...
    ocfs2_inode_unlock
  #no refcount found
....					ocfs2_reflink
                                          ocfs2_inode_lock
                                          ...
                                          ocfs2_inode_unlock
                                          #now, refcount flag set on extent

                                        ...
                                        flush change to disk

ocfs2_direct_IO_get_blocks
  ocfs2_get_clusters
    #extent map miss
    #buffer_head miss
    read extents from disk
  found refcount flag on extent
  crash..

Fix:
Take rw_lock in ocfs2_reflink path

Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-23 16:47:45 -07:00
..
cluster
dlm ocfs2: fix deadlock when two nodes are converting same lock from PR to EX and idletimeout closes conn 2014-06-23 16:47:45 -07:00
dlmfs
Kconfig
Makefile
acl.c
acl.h
alloc.c
alloc.h
aops.c
aops.h
blockcheck.c
blockcheck.h
buffer_head_io.c
buffer_head_io.h
dcache.c
dcache.h
dir.c
dir.h
dlmglue.c
dlmglue.h
export.c
export.h
extent_map.c
extent_map.h
file.c
file.h
heartbeat.c
heartbeat.h
inode.c
inode.h
ioctl.c
ioctl.h
journal.c
journal.h
localalloc.c
localalloc.h
locks.c
locks.h
mmap.c
mmap.h
move_extents.c
move_extents.h
namei.c
namei.h
ocfs1_fs_compat.h
ocfs2.h
ocfs2_fs.h
ocfs2_ioctl.h
ocfs2_lockid.h
ocfs2_lockingver.h
ocfs2_trace.h
quota.h
quota_global.c
quota_local.c
refcounttree.c ocfs2: refcount: take rw_lock in ocfs2_reflink 2014-06-23 16:47:45 -07:00
refcounttree.h
reservations.c
reservations.h
resize.c
resize.h
slot_map.c
slot_map.h
stack_o2cb.c
stack_user.c
stackglue.c
stackglue.h
suballoc.c
suballoc.h
super.c ocfs2: revert "ocfs2: fix NULL pointer dereference when dismount and ocfs2rec simultaneously" 2014-06-23 16:47:45 -07:00
super.h
symlink.c
symlink.h
sysfile.c
sysfile.h
uptodate.c
uptodate.h
xattr.c
xattr.h