FAILED: patch "[PATCH] ocfs2: fix data corruption after failed write" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x 90410bcf873cf05f54a32183afff0161f44f9715
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '[email protected]' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

90410bcf873c ("ocfs2: fix data corruption after failed write")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 90410bcf873cf05f54a32183afff0161f44f9715 Mon Sep 17 00:00:00 2001
From: Jan Kara via Ocfs2-devel <[email protected]>
Date: Thu, 2 Mar 2023 16:38:43 +0100
Subject: [PATCH] ocfs2: fix data corruption after failed write

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.

index 1d65f6ef00ca..0394505fdce3 100644
@@ -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);

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From: Jan Kara via Ocfs2-devel <[email protected]>

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.

---
 fs/ocfs2/aops.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

index b6948813eb06..1353db3f7f48 100644
@@ -2003,11 +2003,25 @@ 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);

2.24.4

Now queued up, thanks.

greg k-h