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| author | Eric Sandeen <sandeen@redhat.com> | 2010-05-16 01:00:00 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-07-05 11:08:45 -0700 |
| commit | 805fe57fb54f9f66256a2c0f81b11abeb83b0142 (patch) | |
| tree | 84b704c45ae914f21fbb3b0fed4e3f14a80b8ab6 | |
| parent | f5cdcd6bb088de9c8ce7b63a2487f7064305c03c (diff) | |
| download | lwn-805fe57fb54f9f66256a2c0f81b11abeb83b0142.tar.gz lwn-805fe57fb54f9f66256a2c0f81b11abeb83b0142.zip | |
ext4: check s_log_groups_per_flex in online resize code
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>
| -rw-r--r-- | fs/ext4/resize.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index 00704312f4f7..f7f5995efce6 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -935,7 +935,8 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input) 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 += |