linux-kernel - [PATCH] ceph: fix NULL vs IS_ERR() bug in ceph_zero_partial

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Message-ID: <685c1424.050a0220.baa8.d6a1@mx.google.com>
Date: Wed, 25 Jun 2025 10:22:11 -0500
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Xiubo Li <xiubli@...hat.com>
Cc: Ilya Dryomov <idryomov@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Matthew Wilcox (Oracle)" <willy@...radead.org>,
	ceph-devel@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: [PATCH] ceph: fix NULL vs IS_ERR() bug in ceph_zero_partial_page()

The filemap_lock_folio() never returns NULL.  It returns error pointers.
Update the checking to match.

Fixes: 483239f03149 ("ceph: convert ceph_zero_partial_page() to use a folio")
Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
---
 fs/ceph/file.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index d5c674d2ba8a..f6e63265c516 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -2536,12 +2536,13 @@ static inline void ceph_zero_partial_page(struct inode *inode,
 	struct folio *folio;
 
 	folio = filemap_lock_folio(inode->i_mapping, offset >> PAGE_SHIFT);
-	if (folio) {
-		folio_wait_writeback(folio);
-		folio_zero_range(folio, offset_in_folio(folio, offset), size);
-		folio_unlock(folio);
-		folio_put(folio);
-	}
+	if (IS_ERR(folio))
+		return;
+
+	folio_wait_writeback(folio);
+	folio_zero_range(folio, offset_in_folio(folio, offset), size);
+	folio_unlock(folio);
+	folio_put(folio);
 }
 
 static void ceph_zero_pagecache_range(struct inode *inode, loff_t offset,
-- 
2.47.2