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| author |   Tao Ma <boyu.mt@taobao.com> | 2011-03-03 22:58:37 +0800 |
|---|---|---|
| committer |   Jan Kara <jack@suse.cz> | 2011-03-04 00:34:15 +0100 |
| commit | 425fa41072b7dce3d88f392b335e561a770aa6c3 (patch) | |
| tree | 2af8bd9feeb23f1bd847159397360ca256a8bc1d /fs/ext3/balloc.c | |
| parent | jbd: Remove one to many n's in a word. (diff) | |
| download | linux-dev-425fa41072b7dce3d88f392b335e561a770aa6c3.tar.xz linux-dev-425fa41072b7dce3d88f392b335e561a770aa6c3.zip | |
ext3: Fix an overflow in ext3_trim_fs.
In a bs=4096 volume, if we call FITRIM with the following parameter as
fstrim_range(start = 102400, len = 134144000, minlen = 10240), with the
following code:
if (len >= EXT3_BLOCKS_PER_GROUP(sb))
len -= (EXT3_BLOCKS_PER_GROUP(sb) - first_block);
else
last_block = first_block + len;
So if len < EXT3_BLOCKS_PER_GROUP while first_block + len >
EXT3_BLOCKS_PER_GROUP, last_block will be set to an overflow value
which exceeds EXT3_BLOCKS_PER_GROUP.
This patch fixes it and adjusts len and last_block accordingly.
Cc: Lukas Czerner <lczerner@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/ext3/balloc.c')
| -rw-r--r-- | fs/ext3/balloc.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c index db1906b4e39c..153242187fce 100644 --- a/fs/ext3/balloc.c +++ b/fs/ext3/balloc.c @@ -2127,10 +2127,15 @@ int ext3_trim_fs(struct super_block *sb, struct fstrim_range *range) if (free_blocks < minlen) continue; - if (len >= EXT3_BLOCKS_PER_GROUP(sb)) - len -= (EXT3_BLOCKS_PER_GROUP(sb) - first_block); - else + /* + * For all the groups except the last one, last block will + * always be EXT3_BLOCKS_PER_GROUP(sb), so we only need to + * change it for the last group in which case first_block + + * len < EXT3_BLOCKS_PER_GROUP(sb). + */ + if (first_block + len < EXT3_BLOCKS_PER_GROUP(sb)) last_block = first_block + len; + len -= last_block - first_block; ret = ext3_trim_all_free(sb, group, first_block, last_block, minlen); |