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| author | Jan Kara <jack@suse.cz> | 2019-02-11 13:30:32 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-03-23 08:44:36 +0100 |
| commit | 8b710dc8a5e2a4c3202f61e6cfa3bae07c70fec9 (patch) | |
| tree | 38e6fb466cd89c3376979d401d17bec0dbf7ce43 | |
| parent | 0d97ba8b9a5fac7b577ab12b77819def430f1868 (diff) | |
| download | linux-stable-8b710dc8a5e2a4c3202f61e6cfa3bae07c70fec9.tar.gz linux-stable-8b710dc8a5e2a4c3202f61e6cfa3bae07c70fec9.tar.bz2 linux-stable-8b710dc8a5e2a4c3202f61e6cfa3bae07c70fec9.zip | |
ext4: fix crash during online resizing
commit f96c3ac8dfc24b4e38fc4c2eba5fea2107b929d1 upstream.
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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 2fc1564f62dd..4bd12247a9be 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1928,7 +1928,8 @@ 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 */ } |