On Wed, Jul 18, 2018 at 08:50:40AM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > > Christoph Hellwig reported seeing the following assertion in > generic/051: > > XFS: Assertion failed: tp->t_firstblock == NULLFSBLOCK, file: fs/xfs/libxfs5 > ------------[ cut here ]------------ > kernel BUG at fs/xfs/xfs_message.c:102! > invalid opcode: 0000 [#1] SMP PTI > CPU: 2 PID: 20757 Comm: fsstress Not tainted 4.18.0-rc4+ #3969 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-1 04/01/4 > RIP: 0010:assfail+0x23/0x30 > Code: c3 66 0f 1f 44 00 00 48 89 f1 41 89 d0 48 c7 c6 88 e0 8c 82 48 89 fa > RSP: 0018:ffff88012dc43c08 EFLAGS: 00010202 > RAX: 0000000000000000 RBX: ffff88012dc43ca0 RCX: 0000000000000000 > RDX: 00000000ffffffc0 RSI: 000000000000000a RDI: ffffffff828480eb > RBP: ffff88012aa92758 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: f000000000000000 R12: 0000000000000000 > R13: ffff88012dc43d48 R14: ffff88013092e7e8 R15: 0000000000000014 > FS: 00007f8d689b8e80(0000) GS:ffff88013fd00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f8d689c7000 CR3: 000000012ba6a000 CR4: 00000000000006e0 > Call Trace: > xfs_defer_init+0xff/0x160 > xfs_reflink_remap_extent+0x31b/0xa00 > xfs_reflink_remap_blocks+0xec/0x4a0 > xfs_reflink_remap_range+0x3a1/0x650 > xfs_file_dedupe_range+0x39/0x50 > vfs_dedupe_file_range+0x218/0x260 > do_vfs_ioctl+0x262/0x6a0 > ? __se_sys_newfstat+0x3c/0x60 > ksys_ioctl+0x35/0x60 > __x64_sys_ioctl+0x11/0x20 > do_syscall_64+0x4b/0x190 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The root cause of the assertion failure is that xfs_defer_finish doesn't > roll the transaction after processing all the deferred items. Therefore > it returns a dirty transaction to the caller, which leaves the caller at > risk of exceeding the transaction reservation if it logs more items. > > Brian Foster's patchset to move the defer_ops firstblock into the > transaction requires t_firstblock == NULLFSBLOCK upon defer_ops > initialization, which is how this was noticed at all. > > Reported-by: Christoph Hellwig <hch@xxxxxx> > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > --- Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx> I was about ready to post the embedded dfops series but this reminds me that this last roll should be optimized out in the xfs_defer_finish() -> xfs_trans_commit() case. Technically a commit of a clean transaction doesn't have to do anything, but that would at least avoid the unnecessary regrant that occurs during the roll. Hmm, I may just post the series as is for initial review and then tack on a patch for the last bit later.. Brian > fs/xfs/libxfs/xfs_defer.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > > diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c > index c3e5bffda4f5..3ba8bb308c3c 100644 > --- a/fs/xfs/libxfs/xfs_defer.c > +++ b/fs/xfs/libxfs/xfs_defer.c > @@ -424,6 +424,12 @@ xfs_defer_finish( > cleanup_fn(*tp, state, error); > } > > + /* > + * Roll the transaction once more to avoid returning to the caller > + * with a dirty transaction. > + */ > + if ((*tp)->t_flags & XFS_TRANS_DIRTY) > + error = xfs_defer_trans_roll(tp, dop); > out: > (*tp)->t_agfl_dfops = orig_dop; > if (error) > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
