xfs: restore shutdown check in mapped write fault path

XFS triggers an iomap warning in the write fault path due to a
!PageUptodate() page if a write fault happens to occur on a page
that recently failed writeback. The iomap writeback error handling
code can clear the Uptodate flag if no portion of the page is
submitted for I/O. This is reproduced by fstest generic/019, which
combines various forms of I/O with simulated disk failures that
inevitably lead to filesystem shutdown (which then unconditionally
fails page writeback).

This is a regression introduced by commit f150b4234397 ("xfs: split
the iomap ops for buffered vs direct writes") due to the removal of
a shutdown check and explicit error return in the ->iomap_begin()
path used by the write fault path. The explicit error return
historically translated to a SIGBUS, but now carries on with iomap
processing where it complains about the unexpected state. Restore
the shutdown check to xfs_buffered_write_iomap_begin() to restore
historical behavior.

Fixes: f150b4234397 ("xfs: split the iomap ops for buffered vs direct writes")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 70c341658c01101cc2e7ae2e4f391e88f4850ac0..6594f572096e688b3f013811a8ce9e3f5bd6474e 100644 (file)
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -860,6 +860,9 @@ xfs_buffered_write_iomap_begin(
        int                     allocfork = XFS_DATA_FORK;
        int                     error = 0;
 
+       if (XFS_FORCED_SHUTDOWN(mp))
+               return -EIO;
+
        /* we can't use delayed allocations when using extent size hints */
        if (xfs_get_extsz_hint(ip))
                return xfs_direct_write_iomap_begin(inode, offset, count,