ocfs2: fix data corruption after failed write

commit 90410bcf873cf05f54a32183afff0161f44f9715 upstream.

When buffered write fails to copy data into underlying page cache page,
ocfs2_write_end_nolock() just zeroes out and dirties the page.  This can
leave dirty page beyond EOF and if page writeback tries to write this page
before write succeeds and expands i_size, page gets into inconsistent
state where page dirty bit is clear but buffer dirty bits stay set
resulting in page data never getting written and so data copied to the
page is lost.  Fix the problem by invalidating page beyond EOF after
failed write.

Link: https://lkml.kernel.org/r/20230302153843.18499-1-jack@suse.cz
Fixes: 31a7abf11e72 ("fs: Don't invalidate page buffers in block_write_full_page()")
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ replace block_invalidate_folio to block_invalidatepage ]
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 7f66e33424750c3f3b6e64148cbb8855138808bd..91702ebffe84ccb2014603df30ce20f41d9fbd76 100644 (file)
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1990,11 +1990,25 @@ int ocfs2_write_end_nolock(struct address_space *mapping,
        }
 
        if (unlikely(copied < len) && wc->w_target_page) {
+               loff_t new_isize;
+
                if (!PageUptodate(wc->w_target_page))
                        copied = 0;
 
-               ocfs2_zero_new_buffers(wc->w_target_page, start+copied,
-                                      start+len);
+               new_isize = max_t(loff_t, i_size_read(inode), pos + copied);
+               if (new_isize > page_offset(wc->w_target_page))
+                       ocfs2_zero_new_buffers(wc->w_target_page, start+copied,
+                                              start+len);
+               else {
+                       /*
+                        * When page is fully beyond new isize (data copy
+                        * failed), do not bother zeroing the page. Invalidate
+                        * it instead so that writeback does not get confused
+                        * put page & buffer dirty bits into inconsistent
+                        * state.
+                        */
+                       block_invalidatepage(wc->w_target_page, 0, PAGE_SIZE);
+               }
        }
        if (wc->w_target_page)
                flush_dcache_page(wc->w_target_page);