On 8/25/21 9:38 AM, JeffleXu wrote:
>
>
> On 8/24/21 4:30 AM, Eric Whitney wrote:
>> * Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>:
>>> When ext4_insert_delayed block receives and recovers from an error from
>>> ext4_es_insert_delayed_block(), e.g., ENOMEM, it does not release the
>>> space it has reserved for that block insertion as it should. One effect
>>> of this bug is that s_dirtyclusters_counter is not decremented and
>>> remains incorrectly elevated until the file system has been unmounted.
>>> This can result in premature ENOSPC returns and apparent loss of free
>>> space.
>>>
>>> Another effect of this bug is that
>>> /sys/fs/ext4/<dev>/delayed_allocation_blocks can remain non-zero even
>>> after syncfs has been executed on the filesystem.
>>>
>>> Besides, add check for s_dirtyclusters_counter when inode is going to be
>>> evicted and freed. s_dirtyclusters_counter can still keep non-zero until
>>> inode is written back in .evict_inode(), and thus the check is delayed
>>> to .destroy_inode().
>>>
>>> Fixes: 51865fda28e5 ("ext4: let ext4 maintain extent status tree")
>>> Cc: <stable@xxxxxxxxxxxxxxx>
>>> Suggested-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
>>> Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
>>> ---
>>> changes since v1:
>>> - improve commit log suggested by Eric Whitney
>>> - update "Suggested-by" title for Gao Xian, who actually found this bug
>>> code
>>> - add check for s_dirtyclusters_counter in .destroy_inode()
>>> ---
>>> fs/ext4/inode.c | 5 +++++
>>> fs/ext4/super.c | 6 ++++++
>>> 2 files changed, 11 insertions(+)
>>>
>>> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
>>> index d8de607849df..73daf9443e5e 100644
>>> --- a/fs/ext4/inode.c
>>> +++ b/fs/ext4/inode.c
>>> @@ -1640,6 +1640,7 @@ static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
>>> struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
>>> int ret;
>>> bool allocated = false;
>>> + bool reserved = false;
>>>
>>> /*
>>> * If the cluster containing lblk is shared with a delayed,
>>> @@ -1656,6 +1657,7 @@ static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
>>> ret = ext4_da_reserve_space(inode);
>>> if (ret != 0) /* ENOSPC */
>>> goto errout;
>>> + reserved = true;
>>> } else { /* bigalloc */
>>> if (!ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk)) {
>>> if (!ext4_es_scan_clu(inode,
>>> @@ -1668,6 +1670,7 @@ static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
>>> ret = ext4_da_reserve_space(inode);
>>> if (ret != 0) /* ENOSPC */
>>> goto errout;
>>> + reserved = true;
>>> } else {
>>> allocated = true;
>>> }
>>> @@ -1678,6 +1681,8 @@ static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
>>> }
>>>
>>> ret = ext4_es_insert_delayed_block(inode, lblk, allocated);
>>> + if (ret && reserved)
>>> + ext4_da_release_space(inode, 1);
>>>
>>> errout:
>>> return ret;
>>> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
>>> index dfa09a277b56..61bf52b58fca 100644
>>> --- a/fs/ext4/super.c
>>> +++ b/fs/ext4/super.c
>>> @@ -1351,6 +1351,12 @@ static void ext4_destroy_inode(struct inode *inode)
>>> true);
>>> dump_stack();
>>> }
>>> +
>>> + if (EXT4_I(inode)->i_reserved_data_blocks)
>>> + ext4_msg(inode->i_sb, KERN_ERR,
>>> + "Inode %lu (%p): i_reserved_data_blocks (%u) not cleared!",
>>> + inode->i_ino, EXT4_I(inode),
>>> + EXT4_I(inode)->i_reserved_data_blocks);
>>> }
>>>
>>> static void init_once(void *foo)
>>> --
>>> 2.27.0
>>>
>>
>> Looks good, passed 4k xfstests-bld regression. Feel free to add:
>>
>> Reviewed-by: Eric Whitney <enwlinux@xxxxxxxxx>
>
>
> Hi tytso, it's a bug fix and it would be great if it could be merged to
> 5.15.
>
ping ...
--
Thanks,
Jeffle
