[PATCH v3 4/6] qnx6: release sb_buf on mmi_fs error path in qnx6_fill_super()

[Hui Peng <benquike@gmail.com>]

In qnx6_fill_super(), when standard qnx6 superblock detection fails, the
driver attempts to probe for an MMI variant via qnx6_mmi_fill_super(s,
silent). If qnx6_mmi_fill_super() fails, qnx6_fill_super() returns -EINVAL
directly without releasing sb_buf (which was allocated by sb_bread(sb, 1)
earlier), leaking the buffer head reference.

Call brelse(sb_buf) on the qnx6_mmi_fill_super() error path in
qnx6_fill_super().

Fixes: 5d026c724220 ("fs: initial qnx6fs addition")
Cc: stable@vger.kernel.org
Tested-by: Matthias Goergens <matthias.goergens@gmail.com>
Reviewed-by: Matthias Goergens <matthias.goergens@gmail.com>
Assisted-by: LLM
Signed-off-by: Hui Peng <benquike@gmail.com>
---
Changes in v3:
- Add Tested-by and Reviewed-by tags from Matthias Goergens.
- Update Fixes: tag SHA to 5d026c724220 ("fs: initial qnx6fs addition").

Changes in v2:
- Split out as patch 4/6 as requested by maintainers.

 fs/qnx6/inode.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/qnx6/inode.c b/fs/qnx6/inode.c
index 70438cf5efdf..49e29a918a2d 100644
--- a/fs/qnx6/inode.c
+++ b/fs/qnx6/inode.c
@@ -340,8 +340,10 @@ static int qnx6_fill_super(struct super_block *s, void *data, int silent)
 		}
 	}
 	if (!sb_buf) {
-		if (qnx6_mmi_fill_super(s, silent))
+		if (qnx6_mmi_fill_super(s, silent)) {
+			brelse(sb_buf);
 			return -EINVAL;
+		}
 		return 0;
 	}
 
-- 
2.55.0.1082.g2b9226bbc0-goog