xfs: up(ic_sema) if flushing data device fails

commit 471de20303dda0b67981e06d59cc6c4a83fd2a3c upstream.

We flush the data device cache before we issue external log IO. If
the flush fails, we shut down the log immediately and return. However,
the iclog->ic_sema is left in a decremented state so let's add an up().
Prior to this patch, xfs/438 would fail consistently when running with
an external log device:

sync
  -> xfs_log_force
  -> xlog_write_iclog
      -> down(&iclog->ic_sema)
      -> blkdev_issue_flush (fail causes us to intiate shutdown)
          -> xlog_force_shutdown
          -> return

unmount
  -> xfs_log_umount
      -> xlog_wait_iclog_completion
          -> down(&iclog->ic_sema) --------> HANG

There is a second early return / shutdown. Make sure the up() happens
for it as well. Also make sure we cleanup the iclog state,
xlog_state_done_syncing, before dropping the iclog lock.

Fixes: b5d721eaae47 ("xfs: external logs need to flush data device")
Fixes: 842a42d126b4 ("xfs: shutdown on failure to add page to log bio")
Fixes: 7d839e325af2 ("xfs: check return codes when flushing block devices")
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Acked-by: Chandan Babu R <chandanbabu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 51c100c..ee206fa 100644 (file)
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1893,9 +1893,7 @@ xlog_write_iclog(
                 * the buffer manually, the code needs to be kept in sync
                 * with the I/O completion path.
                 */
-               xlog_state_done_syncing(iclog);
-               up(&iclog->ic_sema);
-               return;
+               goto sync;
        }
 
        /*
@@ -1925,20 +1923,17 @@ xlog_write_iclog(
                 * avoid shutdown re-entering this path and erroring out again.
                 */
                if (log->l_targ != log->l_mp->m_ddev_targp &&
-                   blkdev_issue_flush(log->l_mp->m_ddev_targp->bt_bdev)) {
-                       xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
-                       return;
-               }
+                   blkdev_issue_flush(log->l_mp->m_ddev_targp->bt_bdev))
+                       goto shutdown;
        }
        if (iclog->ic_flags & XLOG_ICL_NEED_FUA)
                iclog->ic_bio.bi_opf |= REQ_FUA;
 
        iclog->ic_flags &= ~(XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA);
 
-       if (xlog_map_iclog_data(&iclog->ic_bio, iclog->ic_data, count)) {
-               xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
-               return;
-       }
+       if (xlog_map_iclog_data(&iclog->ic_bio, iclog->ic_data, count))
+               goto shutdown;
+
        if (is_vmalloc_addr(iclog->ic_data))
                flush_kernel_vmap_range(iclog->ic_data, count);
 
@@ -1959,6 +1954,12 @@ xlog_write_iclog(
        }
 
        submit_bio(&iclog->ic_bio);
+       return;
+shutdown:
+       xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
+sync:
+       xlog_state_done_syncing(iclog);
+       up(&iclog->ic_sema);
 }
 
 /*