From bf43d84b185e2ff54598f8c58a5a8e63148b6e90 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Mon, 17 Aug 2009 23:48:51 -0400 Subject: [PATCH] ext4: reject too-large filesystems on 32-bit kernels ext4 will happily mount a > 16T filesystem on a 32-bit box, but this is not safe; writes to the block device will wrap past 16T and the page cache can't index past 16T (232 index * 4k pages). Adding another test to the existing "too many sectors" test should do the trick. Add a comment, a relevant return value, and fix the reference to the CONFIG_LBD(AF) option as well. Signed-off-by: Eric Sandeen Signed-off-by: "Theodore Ts'o" --- fs/ext4/super.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index fe3f376b7df2..de67c3657b83 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2550,12 +2550,19 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) goto failed_mount; } - if (ext4_blocks_count(es) > - (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) { + /* + * Test whether we have more sectors than will fit in sector_t, + * and whether the max offset is addressable by the page cache. + */ + if ((ext4_blocks_count(es) > + (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) || + (ext4_blocks_count(es) > + (pgoff_t)(~0ULL) >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits))) { ext4_msg(sb, KERN_ERR, "filesystem" - " too large to mount safely"); + " too large to mount safely on this system"); if (sizeof(sector_t) < 8) ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled"); + ret = -EFBIG; goto failed_mount; } -- 2.20.1