Commit bf43d84b authored by Eric Sandeen's avatar Eric Sandeen Committed by Theodore Ts'o

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: default avatarEric Sandeen <sandeen@redhat.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 0ccff1a4
...@@ -2550,12 +2550,19 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) ...@@ -2550,12 +2550,19 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
goto failed_mount; 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" ext4_msg(sb, KERN_ERR, "filesystem"
" too large to mount safely"); " too large to mount safely on this system");
if (sizeof(sector_t) < 8) if (sizeof(sector_t) < 8)
ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled"); ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
ret = -EFBIG;
goto failed_mount; goto failed_mount;
} }
......
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