From 6dcc693bc57f198bd85a7881eb59a915366fae1e Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Thu, 1 Dec 2016 11:46:40 -0500
Subject: [PATCH] ext4: warn when page is dirtied without buffers
Warn when a page is dirtied without buffers (as that will likely lead to
a crash in ext4_writepages()) or when it gets newly dirtied without the
page being locked (as there is nothing that prevents buffers to get
stripped just before calling set_page_dirty() under memory pressure).
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/ext4/inode.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 861f848159e8..7d95b6174980 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3714,6 +3714,13 @@ static int ext4_journalled_set_page_dirty(struct page *page)
return __set_page_dirty_nobuffers(page);
}
+static int ext4_set_page_dirty(struct page *page)
+{
+ WARN_ON_ONCE(!PageLocked(page) && !PageDirty(page));
+ WARN_ON_ONCE(!page_has_buffers(page));
+ return __set_page_dirty_buffers(page);
+}
+
static const struct address_space_operations ext4_aops = {
.readpage = ext4_readpage,
.readpages = ext4_readpages,
@@ -3721,6 +3728,7 @@ static const struct address_space_operations ext4_aops = {
.writepages = ext4_writepages,
.write_begin = ext4_write_begin,
.write_end = ext4_write_end,
+ .set_page_dirty = ext4_set_page_dirty,
.bmap = ext4_bmap,
.invalidatepage = ext4_invalidatepage,
.releasepage = ext4_releasepage,
@@ -3753,6 +3761,7 @@ static const struct address_space_operations ext4_da_aops = {
.writepages = ext4_writepages,
.write_begin = ext4_da_write_begin,
.write_end = ext4_da_write_end,
+ .set_page_dirty = ext4_set_page_dirty,
.bmap = ext4_bmap,
.invalidatepage = ext4_da_invalidatepage,
.releasepage = ext4_releasepage,
--
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