| Date | Thu, 01 Jul 2010 10:27:02 -0700 | From | Greg KH <> | Subject | [13/23] ext4: check s_log_groups_per_flex in online resize code |
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2.6.27-stable review patch. If anyone has any objections, please let us know.
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From: Eric Sandeen <sandeen@redhat.com>
commit 42007efd569f1cf3bfb9a61da60ef6c2179508ca upstream.
If groups_per_flex < 2, sbi->s_flex_groups[] doesn't get filled out, and every other access to this first tests s_log_groups_per_flex; same thing needs to happen in resize or we'll wander off into a null pointer when doing an online resize of the file system.
Thanks to Christoph Biedl, who came up with the trivial testcase:
# truncate --size 128M fsfile # mkfs.ext3 -F fsfile # tune2fs -O extents,uninit_bg,dir_index,flex_bg,huge_file,dir_nlink,extra_isize fsfile # e2fsck -yDf -C0 fsfile # truncate --size 132M fsfile # losetup /dev/loop0 fsfile # mount /dev/loop0 mnt # resize2fs -p /dev/loop0
https://bugzilla.kernel.org/show_bug.cgi?id=13549
Reported-by: Alessandro Polverini <alex@nibbles.it> Test-case-by: Christoph Biedl <bugzilla.kernel.bpeb@manchmal.in-ulm.de> Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/ext4/resize.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -935,7 +935,8 @@ int ext4_group_add(struct super_block *s percpu_counter_add(&sbi->s_freeinodes_counter, EXT4_INODES_PER_GROUP(sb)); - if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) { + if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG) && + sbi->s_log_groups_per_flex) { ext4_group_t flex_group; flex_group = ext4_flex_group(sbi, input->group); sbi->s_flex_groups[flex_group].free_blocks +=
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