This is a note to let you know that I've just added the patch titled
ext4: avoid overlapping preallocations due to overflow
to the 6.1-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-avoid-overlapping-preallocations-due-to-overflow.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From stable-owner@xxxxxxxxxxxxxxx Sat Oct 28 08:43:23 2023
From: Baokun Li <libaokun1@xxxxxxxxxx>
Date: Sat, 28 Oct 2023 14:47:49 +0800
Subject: ext4: avoid overlapping preallocations due to overflow
To: <stable@xxxxxxxxxxxxxxx>
Cc: <gregkh@xxxxxxxxxxxxxxxxxxx>, <sashal@xxxxxxxxxx>, <tytso@xxxxxxx>, <jack@xxxxxxx>, <ritesh.list@xxxxxxxxx>, <patches@xxxxxxxxxxxxxxx>, <yangerkun@xxxxxxxxxx>, <libaokun1@xxxxxxxxxx>
Message-ID: <20231028064749.833278-3-libaokun1@xxxxxxxxxx>
From: Baokun Li <libaokun1@xxxxxxxxxx>
commit bedc5d34632c21b5adb8ca7143d4c1f794507e4c upstream.
Let's say we want to allocate 2 blocks starting from 4294966386, after
predicting the file size, start is aligned to 4294965248, len is changed
to 2048, then end = start + size = 0x100000000. Since end is of
type ext4_lblk_t, i.e. uint, end is truncated to 0.
This causes (pa->pa_lstart >= end) to always hold when checking if the
current extent to be allocated crosses already preallocated blocks, so the
resulting ac_g_ex may cross already preallocated blocks. Hence we convert
the end type to loff_t and use pa_logical_end() to avoid overflow.
Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230724121059.11834-4-libaokun1@xxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/mballoc.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4022,8 +4022,7 @@ ext4_mb_normalize_request(struct ext4_al
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_super_block *es = sbi->s_es;
int bsbits, max;
- ext4_lblk_t end;
- loff_t size, start_off;
+ loff_t size, start_off, end;
loff_t orig_size __maybe_unused;
ext4_lblk_t start;
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
@@ -4131,7 +4130,7 @@ ext4_mb_normalize_request(struct ext4_al
/* check we don't cross already preallocated blocks */
rcu_read_lock();
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
- ext4_lblk_t pa_end;
+ loff_t pa_end;
if (pa->pa_deleted)
continue;
@@ -4141,8 +4140,7 @@ ext4_mb_normalize_request(struct ext4_al
continue;
}
- pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
- pa->pa_len);
+ pa_end = pa_logical_end(EXT4_SB(ac->ac_sb), pa);
/* PA must not overlap original request */
BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end ||
@@ -4171,12 +4169,11 @@ ext4_mb_normalize_request(struct ext4_al
/* XXX: extra loop to check we really don't overlap preallocations */
rcu_read_lock();
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
- ext4_lblk_t pa_end;
+ loff_t pa_end;
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0) {
- pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
- pa->pa_len);
+ pa_end = pa_logical_end(EXT4_SB(ac->ac_sb), pa);
BUG_ON(!(start >= pa_end || end <= pa->pa_lstart));
}
spin_unlock(&pa->pa_lock);
Patches currently in stable-queue which might be from stable-owner@xxxxxxxxxxxxxxx are
queue-6.1/ext4-avoid-overlapping-preallocations-due-to-overflow.patch
queue-6.1/ext4-fix-bug-in-ext4_mb_new_inode_pa-due-to-overflow.patch
queue-6.1/ext4-add-two-helper-functions-extent_logical_end-and-pa_logical_end.patch
