On 2017/3/22 22:21, Jaegeuk Kim wrote:
> On 03/22, Chao Yu wrote:
>> On 2017/3/22 16:42, Chao Yu wrote:
>>> On 2017/3/22 0:18, Jaegeuk Kim wrote:
>>>> On 03/20, Kinglong Mee wrote:
>>>>> On 3/20/2017 11:08, Jaegeuk Kim wrote:
>>>>>> Hi Kinglong,
>>>>>>
>>>>>> On 03/18, Kinglong Mee wrote:
>>>>>>> It's better coping all valid xattr data includes the last zero.
>>>>>>
>>>>>> Why do we need this?
>>>>>>
>>>>>> The size of txattr_addr would be larger than the space we need.
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>>>
>>>>>>> Signed-off-by: Kinglong Mee <kinglong...@gmail.com>
>>>>>>> ---
>>>>>>> fs/f2fs/xattr.c | 4 ++--
>>>>>>> fs/f2fs/xattr.h | 4 ++--
>>>>>>> 2 files changed, 4 insertions(+), 4 deletions(-)
>>>>>>>
>>>>>>> diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
>>>>>>> index aff7619..41785c9 100644
>>>>>>> --- a/fs/f2fs/xattr.c
>>>>>>> +++ b/fs/f2fs/xattr.c
>>>>>>> @@ -249,7 +249,7 @@ static int lookup_all_xattrs(struct inode *inode,
>>>>>>> struct page *ipage,
>>>>>>> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>>>>>> void *cur_addr, *txattr_addr, *last_addr = NULL;
>>>>>>> nid_t xnid = F2FS_I(inode)->i_xattr_nid;
>>>>>>> - unsigned int size = xnid ? VALID_XATTR_BLOCK_SIZE : 0;
>>>>>
>>>>> Here maybe does not copy the last zero.
>>>>
>>>> The below kzalloc() will make it zero. Any problem?
>>>
>>> There is no problem without this change, but anyway, IMO, it needs to do
>>> cleanup
>>> as it can provider better readability making allocated size and copied size
>>> be
>>> consistent among lookup_all_xattrs, read_all_xattrs and write_all_xattrs.
>>>
>>> And since during allocation we have initialize memory with zero, so I
>>> prefer to
>>> not copy extra reserved xattr space.
>>>
>>> Jaegeuk, Kinglong, how about changing like below:
>>>
>>> ---
>>> fs/f2fs/xattr.c | 27 ++++++++++++---------------
>>> fs/f2fs/xattr.h | 3 ++-
>>> 2 files changed, 14 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
>>> index aff7619e3f96..308b06664068 100644
>>> --- a/fs/f2fs/xattr.c
>>> +++ b/fs/f2fs/xattr.c
>>> @@ -250,15 +250,13 @@ static int lookup_all_xattrs(struct inode *inode,
>>> struct
>>> page *ipage,
>>> void *cur_addr, *txattr_addr, *last_addr = NULL;
>>> nid_t xnid = F2FS_I(inode)->i_xattr_nid;
>>> unsigned int size = xnid ? VALID_XATTR_BLOCK_SIZE : 0;
>>> - unsigned int inline_size = 0;
>>> + unsigned int inline_size = inline_xattr_size(inode);
>>> int err = 0;
>>>
>>> - inline_size = inline_xattr_size(inode);
>>> -
>>> if (!size && !inline_size)
>>> return -ENODATA;
>>>
>>> - txattr_addr = kzalloc(inline_size + size + sizeof(__u32),
>>> + txattr_addr = kzalloc(inline_size + size + RESERVED_XATTR_SIZE,
>>> GFP_F2FS_ZERO);
>>> if (!txattr_addr)
>>> return -ENOMEM;
>>> @@ -328,13 +326,14 @@ static int read_all_xattrs(struct inode *inode, struct
>>> page *ipage,
>>> {
>>> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>> struct f2fs_xattr_header *header;
>>> - size_t size = PAGE_SIZE, inline_size = 0;
>>> + nid_t xnid = F2FS_I(inode)->i_xattr_nid;
>>> + unsigned int size = xnid ? VALID_XATTR_BLOCK_SIZE : 0;
>>
>> Here, always should assign size with VALID_XATTR_BLOCK_SIZE for enospc case
>> in
>> inline xattr space while adding new xattr entry.
>
> Do you mean any race condition? It seems setxattr is covered by i_mutex, but
> listxattr does not. But, given xnid, i_xattr_nid won't be used below, so it
> looks fine to go with xnid check.
To cover below case
- __f2fs_setxattr
- read_all_xattrs
- write_all_xattrs
- new_node_page
- memcpy
>
> Thanks,
>
>>
>> unsigned int size = VALID_XATTR_BLOCK_SIZE;
>>
>> Thanks,
>>
>>> + unsigned int inline_size = inline_xattr_size(inode);
>>> void *txattr_addr;
>>> int err;
>>>
>>> - inline_size = inline_xattr_size(inode);
>>> -
>>> - txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
>>> + txattr_addr = kzalloc(inline_size + size + RESERVED_XATTR_SIZE,
>>> + GFP_F2FS_ZERO);
>>> if (!txattr_addr)
>>> return -ENOMEM;
>>>
>>> @@ -358,19 +357,19 @@ static int read_all_xattrs(struct inode *inode, struct
>>> page *ipage,
>>> }
>>>
>>> /* read from xattr node block */
>>> - if (F2FS_I(inode)->i_xattr_nid) {
>>> + if (xnid) {
>>> struct page *xpage;
>>> void *xattr_addr;
>>>
>>> /* The inode already has an extended attribute block. */
>>> - xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
>>> + xpage = get_node_page(sbi, xnid);
>>> if (IS_ERR(xpage)) {
>>> err = PTR_ERR(xpage);
>>> goto fail;
>>> }
>>>
>>> xattr_addr = page_address(xpage);
>>> - memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
>>> + memcpy(txattr_addr + inline_size, xattr_addr, size);
>>> f2fs_put_page(xpage, 1);
>>> }
>>>
>>> @@ -392,14 +391,12 @@ static inline int write_all_xattrs(struct inode
>>> *inode,
>>> __u32 hsize,
>>> void *txattr_addr, struct page *ipage)
>>> {
>>> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>> - size_t inline_size = 0;
>>> + size_t inline_size = inline_xattr_size(inode);
>>> void *xattr_addr;
>>> struct page *xpage;
>>> nid_t new_nid = 0;
>>> int err;
>>>
>>> - inline_size = inline_xattr_size(inode);
>>> -
>>> if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
>>> if (!alloc_nid(sbi, &new_nid))
>>> return -ENOSPC;
>>> @@ -454,7 +451,7 @@ static inline int write_all_xattrs(struct inode *inode,
>>> __u32 hsize,
>>> }
>>>
>>> xattr_addr = page_address(xpage);
>>> - memcpy(xattr_addr, txattr_addr + inline_size, MAX_XATTR_BLOCK_SIZE);
And this needs to be kept to avoid remain random data in newly allocated xattr
node page.
Thanks,
>>> + memcpy(xattr_addr, txattr_addr + inline_size, VALID_XATTR_BLOCK_SIZE);
>>> set_page_dirty(xpage);
>>> f2fs_put_page(xpage, 1);
>>>
>>> diff --git a/fs/f2fs/xattr.h b/fs/f2fs/xattr.h
>>> index d5a94928c116..1e7db8d0806e 100644
>>> --- a/fs/f2fs/xattr.h
>>> +++ b/fs/f2fs/xattr.h
>>> @@ -73,7 +73,8 @@ struct f2fs_xattr_entry {
>>> !IS_XATTR_LAST_ENTRY(entry);\
>>> entry = XATTR_NEXT_ENTRY(entry))
>>> #define MAX_XATTR_BLOCK_SIZE (PAGE_SIZE - sizeof(struct node_footer))
>>> -#define VALID_XATTR_BLOCK_SIZE (MAX_XATTR_BLOCK_SIZE - sizeof(__u32))
>>> +#define RESERVED_XATTR_SIZE (sizeof(__u32))
>>> +#define VALID_XATTR_BLOCK_SIZE (MAX_XATTR_BLOCK_SIZE -
>>> RESERVED_XATTR_SIZE)
>>> #define MIN_OFFSET(i) XATTR_ALIGN(inline_xattr_size(i) +
>>> \
>>> VALID_XATTR_BLOCK_SIZE)
>>>
>
> .
>
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