From 47eb055ad3588fc96d34e9e1dd87b210ce62906b Mon Sep 17 00:00:00 2001 From: Jan Kara via Ocfs2-devel Date: Thu, 2 Mar 2023 16:38:43 +0100 Subject: [PATCH] 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: 6dbf7bb55598 ("fs: Don't invalidate page buffers in block_write_full_page()") Signed-off-by: Jan Kara Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Changwei Ge Cc: Gang He Cc: Jun Piao Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/aops.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 1d65f6e..0394505 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -1977,11 +1977,26 @@ 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_invalidate_folio(page_folio(wc->w_target_page), + 0, PAGE_SIZE); + } } if (wc->w_target_page) flush_dcache_page(wc->w_target_page); -- 2.7.4