Ocfs2 devel - Mar 2023 - + ocfs2-fix-data-corruption-after-failed-write.patch added to mm-hotfixes-unstable branch

The patch titled
     Subject: ocfs2: fix data corruption after failed write
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     ocfs2-fix-data-corruption-after-failed-write.patch

This patch will shortly appear at
    
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ocfs2-fix-data-corruption-after-failed-write.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Jan Kara via Ocfs2-devel <ocfs2-devel at oss.oracle.com>
Subject: ocfs2: fix data corruption after failed write
Date: Thu, 2 Mar 2023 16:38:43 +0100

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 at suse.cz
Fixes: 6dbf7bb55598 ("fs: Don't invalidate page buffers in
block_write_full_page()")
Signed-off-by: Jan Kara <jack at suse.cz>
Reviewed-by: Joseph Qi <joseph.qi at linux.alibaba.com>
Cc: Mark Fasheh <mark at fasheh.com>
Cc: Joel Becker <jlbec at evilplan.org>
Cc: Junxiao Bi <junxiao.bi at oracle.com>
Cc: Changwei Ge <gechangwei at live.cn>
Cc: Gang He <ghe at suse.com>
Cc: Jun Piao <piaojun at huawei.com>
Cc: <stable at vger.kernel.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
---


--- a/fs/ocfs2/aops.c~ocfs2-fix-data-corruption-after-failed-write
+++ a/fs/ocfs2/aops.c
@@ -1977,11 +1977,26 @@ int ocfs2_write_end_nolock(struct addres
 	}
 
 	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);
_

Patches currently in -mm which might be from ocfs2-devel at oss.oracle.com are

ocfs2-fix-data-corruption-after-failed-write.patch