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

Gao Xiang
2018-08-13T02:41:41Z

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.

Thanks,
Gao Xiang