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ext4: add two helper functions extent_logical_end() and pa_logical_end()

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commit 43bbddc067 upstream.

When we use lstart + len to calculate the end of free extent or prealloc
space, it may exceed the maximum value of 4294967295(0xffffffff) supported
by ext4_lblk_t and cause overflow, which may lead to various problems.

Therefore, we add two helper functions, extent_logical_end() and
pa_logical_end(), to limit the type of end to loff_t, and also convert
lstart to loff_t for calculation to avoid overflow.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20230724121059.11834-2-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Baokun Li 2023-10-28 14:47:47 +08:00 committed by Greg Kroah-Hartman
parent 9e78e7709f
commit 7a992726f7
2 changed files with 17 additions and 4 deletions
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7
fs/ext4/mballoc.c
View file

@ -4079,7 +4079,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
/* first, let's learn actual file size
* given current request is allocated */
size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
size = extent_logical_end(sbi, &ac->ac_o_ex);
size = size << bsbits;
if (size < i_size_read(ac->ac_inode))
size = i_size_read(ac->ac_inode);
@ -4419,8 +4419,7 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
/* all fields in this condition don't change,
* so we can skip locking for them */
if (ac->ac_o_ex.fe_logical < pa->pa_lstart ||
ac->ac_o_ex.fe_logical >= (pa->pa_lstart +
EXT4_C2B(sbi, pa->pa_len)))
ac->ac_o_ex.fe_logical >= pa_logical_end(sbi, pa))
continue;
/* non-extent files can't have physical blocks past 2^32 */
@ -5241,7 +5240,7 @@ static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
group_pa_eligible = sbi->s_mb_group_prealloc > 0;
inode_pa_eligible = true;
size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
size = extent_logical_end(sbi, &ac->ac_o_ex);
isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
>> bsbits;

14
fs/ext4/mballoc.h
View file

@ -219,6 +219,20 @@ static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
(fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
}
static inline loff_t extent_logical_end(struct ext4_sb_info *sbi,
struct ext4_free_extent *fex)
{
/* Use loff_t to avoid end exceeding ext4_lblk_t max. */
return (loff_t)fex->fe_logical + EXT4_C2B(sbi, fex->fe_len);
}
static inline loff_t pa_logical_end(struct ext4_sb_info *sbi,
struct ext4_prealloc_space *pa)
{
/* Use loff_t to avoid end exceeding ext4_lblk_t max. */
return (loff_t)pa->pa_lstart + EXT4_C2B(sbi, pa->pa_len);
}
typedef int (*ext4_mballoc_query_range_fn)(
struct super_block *sb,
ext4_group_t agno,