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ext4: fix fencepost error in check for inode count overflow during resize

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commit 4f2f76f751 upstream.

ext4_resize_fs() has an off-by-one bug when checking whether growing of
a filesystem will not overflow inode count. As a result it allows a
filesystem with 8192 inodes per group to grow to 64TB which overflows
inode count to 0 and makes filesystem unusable. Fix it.

Cc: stable@vger.kernel.org
Fixes: 3f8a6411fb
Reported-by: Jaco Kroon <jaco@uls.co.za>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jan Kara
2018-05-25 12:51:25 -04:00
committed by Greg Kroah-Hartman
parent 2154254599
commit f3233cb248
1 changed files with 1 additions and 1 deletions
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2
fs/ext4/resize.c
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@ -1905,7 +1905,7 @@ retry:
return 0;
n_group = ext4_get_group_number(sb, n_blocks_count - 1);
if (n_group > (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
ext4_warning(sb, "resize would cause inodes_count overflow");
return -EINVAL;
}