This is a note to let you know that I've just added the patch titled
ext4: add two helper functions extent_logical_end() and pa_logical_end()
to the 6.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-add-two-helper-functions-extent_logical_end-and.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit fe6f11874433799f3964a59aae0283140898d017
Author: Baokun Li <libaokun1@xxxxxxxxxx>
Date: Mon Jul 24 20:10:57 2023 +0800
ext4: add two helper functions extent_logical_end() and pa_logical_end()
[ Upstream commit 43bbddc067883d94de7a43d5756a295439fbe37d ]
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@xxxxxxxxxx>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230724121059.11834-2-libaokun1@xxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index a197ef71b7b02..627c813cf0759 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4433,7 +4433,7 @@ 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);
@@ -4767,7 +4767,6 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_locality_group *lg;
struct ext4_prealloc_space *tmp_pa = NULL, *cpa = NULL;
- loff_t tmp_pa_end;
struct rb_node *iter;
ext4_fsblk_t goal_block;
@@ -4863,9 +4862,7 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
* pa can possibly satisfy the request hence check if it overlaps
* original logical start and stop searching if it doesn't.
*/
- tmp_pa_end = (loff_t)tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len);
-
- if (ac->ac_o_ex.fe_logical >= tmp_pa_end) {
+ if (ac->ac_o_ex.fe_logical >= pa_logical_end(sbi, tmp_pa)) {
spin_unlock(&tmp_pa->pa_lock);
goto try_group_pa;
}
@@ -5770,7 +5767,7 @@ 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;
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index df6b5e7c22741..d7aeb5da7d867 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -233,6 +233,20 @@ 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,
