Sender: Guenter Roeck <groeck7@gmail.com>
From:   Guenter Roeck <linux@roeck-us.net>
To:     Anton Altaparmakov <anton@tuxera.com>
Cc:     linux-ntfs-dev@lists.sourceforge.net, linux-kernel@vger.kernel.org,
        "David S . Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        Joel Stanley <joel@jms.id.au>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Guenter Roeck <linux@roeck-us.net>
Subject: [PATCH v3 2/3] fs: ntfs: Limit NTFS_RW to page sizes smaller than 64k
Date:   Sat, 27 Nov 2021 07:44:41 -0800
Message-Id: <20211127154442.3676290-3-linux@roeck-us.net>
In-Reply-To: <20211127154442.3676290-1-linux@roeck-us.net>
References: <20211127154442.3676290-1-linux@roeck-us.net>
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NTFS_RW code allocates page size dependent arrays on the stack. This
results in build failures if the page size is 64k or larger.

fs/ntfs/aops.c: In function 'ntfs_write_mst_block':
fs/ntfs/aops.c:1311:1: error:
	the frame size of 2240 bytes is larger than 2048 bytes

Since commit f22969a66041 ("powerpc/64s: Default to 64K pages for 64 bit
book3s") this affects ppc:allmodconfig builds, but other architectures
supporting page sizes of 64k or larger are also affected.

Increasing the maximum frame size for affected architectures just to
silence this error does not really help. The frame size would have to be
set to a really large value for 256k pages. Also, a large frame size could
potentially result in stack overruns in this code and elsewhere and is
therefore not desirable. Make NTFS_RW dependent on page sizes smaller than
64k instead.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: Use generic configuration flag
v2: More comprehensive dependencies

 fs/ntfs/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ntfs/Kconfig b/fs/ntfs/Kconfig
index 1667a7e590d8..f93e69a61283 100644
--- a/fs/ntfs/Kconfig
+++ b/fs/ntfs/Kconfig
@@ -52,6 +52,7 @@ config NTFS_DEBUG
 config NTFS_RW
 	bool "NTFS write support"
 	depends on NTFS_FS
+	depends on PAGE_SIZE_LESS_THAN_64KB
 	help
 	  This enables the partial, but safe, write support in the NTFS driver.
 
-- 
2.33.0