[PATCH] gfs2: Fix error pointer dereference

[Ethan Tidmore]

The function __filemap_get_folio() can return an error pointer and is
not checked for one. Add check for error pointer.

Detected by Smatch:
fs/gfs2/meta_io.c:147 gfs2_getbuf() error:
'folio' dereferencing possible ERR_PTR()

Fixes: 0eb751791df86 ("gfs2: convert gfs2_getbuf() to folios")
Signed-off-by: Ethan Tidmore <ethantidmore06@xxxxxxxxx>
---
 fs/gfs2/meta_io.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 3c8e4553102d..9c0ba4c3cb29 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -144,6 +144,8 @@ struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
 		folio = __filemap_get_folio(mapping, index,
 				FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
 				mapping_gfp_mask(mapping) | __GFP_NOFAIL);
+		if (IS_ERR(folio))
+			return NULL;
 		bh = folio_buffers(folio);
 		if (!bh)
 			bh = create_empty_buffers(folio,
-- 
2.53.0