Re: [PATCH 3/8] staging: erofs: add error handling for xattr submodule

Chao Yu
2018-08-13T08:15:53Z

Hi Xiang,

On 2018/8/13 10:36, Gao Xiang wrote:
> Hi Chao,
>
> On 2018/8/13 10:00, Chao Yu wrote:
>> On 2018/8/12 22:01, Chao Yu wrote:
>>> From: Gao Xiang <gaoxiang25@huawei.com>
>>>
>>> This patch enhances the missing error handling code for
>>> xattr submodule, which improves the stability for the rare cases.
>>>
>>> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
>>> Reviewed-by: Chao Yu <yuchao0@huawei.com>
>>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>>> ---
>>> drivers/staging/erofs/internal.h | 6 +-
>>> drivers/staging/erofs/xattr.c | 120 ++++++++++++++++++++-----------
>>> 2 files changed, 83 insertions(+), 43 deletions(-)
>>>
>>> diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
>>> index a756abeff7e9..8951e01216e3 100644
>>> --- a/drivers/staging/erofs/internal.h
>>> +++ b/drivers/staging/erofs/internal.h
>>> @@ -485,10 +485,10 @@ struct erofs_map_blocks_iter {
>>>
>>>
>>> static inline struct page *
>>> -erofs_get_inline_page_nofail(struct inode *inode,
>>> - erofs_blk_t blkaddr)
>>> +erofs_get_inline_page(struct inode *inode,
>>> + erofs_blk_t blkaddr)
>>> {
>>> - return erofs_get_meta_page_nofail(inode->i_sb,
>>> + return erofs_get_meta_page(inode->i_sb,
>>> blkaddr, S_ISDIR(inode->i_mode));
>>> }
>>>
>>> diff --git a/drivers/staging/erofs/xattr.c b/drivers/staging/erofs/xattr.c
>>> index 2593c856b079..1b5815fc70db 100644
>>> --- a/drivers/staging/erofs/xattr.c
>>> +++ b/drivers/staging/erofs/xattr.c
>>> @@ -24,16 +24,25 @@ struct xattr_iter {
>>>
>>> static inline void xattr_iter_end(struct xattr_iter *it, bool atomic)
>>> {
>>> - /* only init_inode_xattrs use non-atomic once */
>>> + /* the only user of kunmap() is 'init_inode_xattrs' */
>>> if (unlikely(!atomic))
>>> kunmap(it->page);
>>> else
>>> kunmap_atomic(it->kaddr);
>>> +
>>> unlock_page(it->page);
>>> put_page(it->page);
>>> }
>>>
>>> -static void init_inode_xattrs(struct inode *inode)
>>> +static inline void xattr_iter_end_final(struct xattr_iter *it)
>>> +{
>>> + if (unlikely(it->page == NULL))
>>> + return;
>>> +
>>> + xattr_iter_end(it, true);
>>> +}
>>> +
>>> +static int init_inode_xattrs(struct inode *inode)
>>> {
>>> struct xattr_iter it;
>>> unsigned i;
>>> @@ -44,7 +53,7 @@ static void init_inode_xattrs(struct inode *inode)
>>> bool atomic_map;
>>>
>>> if (likely(inode_has_inited_xattr(inode)))
>>> - return;
>>> + return 0;
>>>
>>> vi = EROFS_V(inode);
>>> BUG_ON(!vi->xattr_isize);
>>> @@ -54,8 +63,9 @@ static void init_inode_xattrs(struct inode *inode)
>>> it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize);
>>> it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);
>>>
>>> - it.page = erofs_get_inline_page_nofail(inode, it.blkaddr);
>>> - BUG_ON(IS_ERR(it.page));
>>> + it.page = erofs_get_inline_page(inode, it.blkaddr);
>>> + if (IS_ERR(it.page))
>>> + return PTR_ERR(it.page);
>>>
>>> /* read in shared xattr array (non-atomic, see kmalloc below) */
>>> it.kaddr = kmap(it.page);
>>> @@ -64,9 +74,12 @@ static void init_inode_xattrs(struct inode *inode)
>>> ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);
>>>
>>> vi->xattr_shared_count = ih->h_shared_count;
>>> - vi->xattr_shared_xattrs = (unsigned *)kmalloc_array(
>>> - vi->xattr_shared_count, sizeof(unsigned),
>>> - GFP_KERNEL | __GFP_NOFAIL);
>>> + vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
>>> + sizeof(unsigned), GFP_KERNEL);
>>> + if (unlikely(vi->xattr_shared_xattrs == NULL)) {
>>> + xattr_iter_end(&it, atomic_map);
>>> + return -ENOMEM;
>>> + }
>>>
>>> /* let's skip ibody header */
>>> it.ofs += sizeof(struct erofs_xattr_ibody_header);
>>> @@ -77,9 +90,10 @@ static void init_inode_xattrs(struct inode *inode)
>>> BUG_ON(it.ofs != EROFS_BLKSIZ);
>>> xattr_iter_end(&it, atomic_map);
>>>
>>> - it.page = erofs_get_meta_page_nofail(sb,
>>> + it.page = erofs_get_meta_page(sb,
>>> ++it.blkaddr, S_ISDIR(inode->i_mode));
>>> - BUG_ON(IS_ERR(it.page));
>>> + if (IS_ERR(it.page))
>>> + return PTR_ERR(it.page);
>>>
>>> it.kaddr = kmap_atomic(it.page);
>>> atomic_map = true;
>>> @@ -92,6 +106,7 @@ static void init_inode_xattrs(struct inode *inode)
>>> xattr_iter_end(&it, atomic_map);
>>>
>>> inode_set_inited_xattr(inode);
>>> + return 0;
>>> }
>>>
>>> struct xattr_iter_handlers {
>>> @@ -101,19 +116,24 @@ struct xattr_iter_handlers {
>>> void (*value)(struct xattr_iter *, unsigned, char *, unsigned);
>>> };
>>>
>>> -static void xattr_iter_fixup(struct xattr_iter *it)
>>> +static inline int xattr_iter_fixup(struct xattr_iter *it)
>>> {
>>> - if (unlikely(it->ofs >= EROFS_BLKSIZ)) {
>>> - xattr_iter_end(it, true);
>>> + if (likely(it->ofs < EROFS_BLKSIZ))
>>> + return 0;
>>>
>>> - it->blkaddr += erofs_blknr(it->ofs);
>>> - it->page = erofs_get_meta_page_nofail(it->sb,
>>> - it->blkaddr, false);
>>> - BUG_ON(IS_ERR(it->page));
>>> + xattr_iter_end(it, true);
>>>
>>> - it->kaddr = kmap_atomic(it->page);
>>> - it->ofs = erofs_blkoff(it->ofs);
>>> + it->blkaddr += erofs_blknr(it->ofs);
>>> +
>>> + it->page = erofs_get_meta_page(it->sb, it->blkaddr, false);
>>> + if (IS_ERR(it->page)) {
>>> + it->page = NULL;
>>> + return PTR_ERR(it->page);
>> As LKP reported, we need to fix this as below:
>>
>> err = PTR_ERR(it->page);
>> it->page = NULL;
>> return err;
>>
>> Thanks,
>>
>
> I have seen this at
> https://lists.01.org/pipermail/kbuild-all/2018-August/051187.html
>
> I will fix it soon. Thanks for report.

I checked v2 patch, it looks good to me now. I will send v2 patchset later.

Thanks,

>
> Thanks,
> Gao Xiang
>
> .
>