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| author | Jan Kara <jack@suse.cz> | 2019-02-11 13:30:32 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2019-02-11 13:30:32 -0500 |
| commit | f96c3ac8dfc24b4e38fc4c2eba5fea2107b929d1 (patch) | |
| tree | c538d0bf978b614e228b40e293823807e3f2ef05 /fs/ext4/resize.c | |
| parent | 6e589291f4b1b700ca12baec5930592a0d51e63c (diff) | |
| download | linux-f96c3ac8dfc24b4e38fc4c2eba5fea2107b929d1.tar.bz2 | |
ext4: fix crash during online resizing
When computing maximum size of filesystem possible with given number of
group descriptor blocks, we forget to include s_first_data_block into
the number of blocks. Thus for filesystems with non-zero
s_first_data_block it can happen that computed maximum filesystem size
is actually lower than current filesystem size which confuses the code
and eventually leads to a BUG_ON in ext4_alloc_group_tables() hitting on
flex_gd->count == 0. The problem can be reproduced like:
truncate -s 100g /tmp/image
mkfs.ext4 -b 1024 -E resize=262144 /tmp/image 32768
mount -t ext4 -o loop /tmp/image /mnt
resize2fs /dev/loop0 262145
resize2fs /dev/loop0 300000
Fix the problem by properly including s_first_data_block into the
computed number of filesystem blocks.
Fixes: 1c6bd7173d66 "ext4: convert file system to meta_bg if needed..."
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4/resize.c')
| -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 48421de803b7..3d9b18505c0c 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1960,7 +1960,8 @@ retry: le16_to_cpu(es->s_reserved_gdt_blocks); n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb); n_blocks_count = (ext4_fsblk_t)n_group * - EXT4_BLOCKS_PER_GROUP(sb); + EXT4_BLOCKS_PER_GROUP(sb) + + le32_to_cpu(es->s_first_data_block); n_group--; /* set to last group number */ } |