korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-24 12:44:11 +08:00
Code Issues Packages Projects Releases Wiki Activity

ext3: fix start and len arguments handling in ext3_trim_fs()

Browse Source 
The overflow might happen when passing blocknr into
ext3_get_group_no_and_offset(), because it expects type ext3_fsblk_t
which might be smaller than uint64_t. This will most likely happen when
calling FITRIM with the default argument len = ULLONG_MAX.

Fix this by using "end" variable instead of "start+len" as it is easier
to get right and specifically check that the end is not beyond the end
of the file system, so we are sure that the result of
get_group_no_and_offset() will not overflow. Otherwise truncate it to
the size of the file system.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Lukas Czerner 2012-03-02 13:09:05 +01:00 committed by Jan Kara
parent a0391a3ae9
commit e703c20613
1 changed files with 39 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
fs/ext3/balloc.c
View File

@ -1973,7 +1973,7 @@ static ext3_grpblk_t ext3_trim_all_free(struct super_block *sb,
sbi = EXT3_SB(sb);
/* Walk through the whole group */
while (start < max) {
while (start <= max) {
start = bitmap_search_next_usable_block(start, bitmap_bh, max);
if (start < 0)
break;
@ -1983,7 +1983,7 @@ static ext3_grpblk_t ext3_trim_all_free(struct super_block *sb,
* Allocate contiguous free extents by setting bits in the
* block bitmap
*/
while (next < max
while (next <= max
&& claim_block(sb_bgl_lock(sbi, group),
next, bitmap_bh)) {
next++;
@ -2094,73 +2094,74 @@ err_out:
*/
int ext3_trim_fs(struct super_block *sb, struct fstrim_range *range)
{
ext3_grpblk_t last_block, first_block, free_blocks;
unsigned long first_group, last_group;
unsigned long group, ngroups;
ext3_grpblk_t last_block, first_block;
unsigned long group, first_group, last_group;
struct ext3_group_desc *gdp;
struct ext3_super_block *es = EXT3_SB(sb)->s_es;
uint64_t start, len, minlen, trimmed;
uint64_t start, minlen, end, trimmed = 0;
ext3_fsblk_t first_data_blk =
le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block);
ext3_fsblk_t max_blks = le32_to_cpu(es->s_blocks_count);
int ret = 0;
start = (range->start >> sb->s_blocksize_bits) +
le32_to_cpu(es->s_first_data_block);
len = range->len >> sb->s_blocksize_bits;
start = range->start >> sb->s_blocksize_bits;
end = start + (range->len >> sb->s_blocksize_bits) - 1;
minlen = range->minlen >> sb->s_blocksize_bits;
trimmed = 0;
if (unlikely(minlen > EXT3_BLOCKS_PER_GROUP(sb)))
if (unlikely(minlen > EXT3_BLOCKS_PER_GROUP(sb)) ||
unlikely(start >= max_blks))
return -EINVAL;
if (start >= max_blks)
return -EINVAL;
if (start + len > max_blks)
len = max_blks - start;
if (end >= max_blks)
end = max_blks - 1;
if (end <= first_data_blk)
goto out;
if (start < first_data_blk)
start = first_data_blk;
ngroups = EXT3_SB(sb)->s_groups_count;
smp_rmb();
/* Determine first and last group to examine based on start and len */
ext3_get_group_no_and_offset(sb, (ext3_fsblk_t) start,
&first_group, &first_block);
ext3_get_group_no_and_offset(sb, (ext3_fsblk_t) (start + len),
ext3_get_group_no_and_offset(sb, (ext3_fsblk_t) end,
&last_group, &last_block);
last_group = (last_group > ngroups - 1) ? ngroups - 1 : last_group;
last_block = EXT3_BLOCKS_PER_GROUP(sb);
if (first_group > last_group)
return -EINVAL;
/* end now represents the last block to discard in this group */
end = EXT3_BLOCKS_PER_GROUP(sb) - 1;
for (group = first_group; group <= last_group; group++) {
gdp = ext3_get_group_desc(sb, group, NULL);
if (!gdp)
break;
free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
if (free_blocks < minlen)
continue;
/*
* 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).
* always be EXT3_BLOCKS_PER_GROUP(sb)-1, so we only need to
* change it for the last group, note that last_block is
* already computed earlier by ext3_get_group_no_and_offset()
*/
if (first_block + len < EXT3_BLOCKS_PER_GROUP(sb))
last_block = first_block + len;
len -= last_block - first_block;
if (group == last_group)
end = last_block;
ret = ext3_trim_all_free(sb, group, first_block,
last_block, minlen);
if (ret < 0)
break;
if (le16_to_cpu(gdp->bg_free_blocks_count) >= minlen) {
ret = ext3_trim_all_free(sb, group, first_block,
end, minlen);
if (ret < 0)
break;
trimmed += ret;
}
trimmed += ret;
/*
* For every group except the first one, we are sure
* that the first block to discard will be block #0.
*/
first_block = 0;
}
if (ret >= 0)
if (ret > 0)
ret = 0;
range->len = trimmed * sb->s_blocksize;
out:
range->len = trimmed * sb->s_blocksize;
return ret;
}