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Message-ID: <19a1340f-0a0d-40a0-9d00-0faf171480f2@kernel.org>
Date: Thu, 28 Dec 2023 23:33:37 +0800
From: Chao Yu <chao@...nel.org>
To: Jaegeuk Kim <jaegeuk@...nel.org>
Cc: linux-f2fs-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/6] f2fs: fix to restrict condition of compress inode
conversion
On 2023/12/13 6:21, Jaegeuk Kim wrote:
> On 12/12, Chao Yu wrote:
>> On 2023/12/12 6:11, Jaegeuk Kim wrote:
>>> On 12/10, Chao Yu wrote:
>>>> This patch adds i_size check during compress inode conversion in order
>>>> to avoid .page_mkwrite races w/ conversion.
>>>
>>> Which race condition do you see?
>>
>> Something like:
>>
>> - f2fs_setflags_common
>> - check S_ISREG && F2FS_HAS_BLOCKS
>> - mkwrite
>> - f2fs_get_block_locked
>> : update metadata in old inode's disk layout
>
> Don't we need to prevent setting this for mmapped file?
Oh, we have used i_sem lock to prevent such race case, however
we missed f2fs_disable_compressed_file():
- f2fs_disable_compressed_file
- check inode_has_data
- f2fs_file_mmap
- mkwrite
- f2fs_get_block_locked
: update metadata in compressed
inode's disk layout
- fi->i_flags &= ~F2FS_COMPR_FL
- clear_inode_flag(inode, FI_COMPRESSED_FILE);
Thanks,
>
>> - set_compress_context
>>
>> Thanks,
>>
>>>
>>>>
>>>> Fixes: 4c8ff7095bef ("f2fs: support data compression")
>>>> Signed-off-by: Chao Yu <chao@...nel.org>
>>>> ---
>>>> fs/f2fs/f2fs.h | 8 +++++++-
>>>> fs/f2fs/file.c | 5 ++---
>>>> 2 files changed, 9 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index 65294e3b0bef..c9b8a1953913 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -4397,13 +4397,19 @@ static inline int set_compress_context(struct inode *inode)
>>>> #endif
>>>> }
>>>> +static inline bool inode_has_data(struct inode *inode)
>>>> +{
>>>> + return (S_ISREG(inode->i_mode) &&
>>>> + (F2FS_HAS_BLOCKS(inode) || i_size_read(inode)));
>>>> +}
>>>> +
>>>> static inline bool f2fs_disable_compressed_file(struct inode *inode)
>>>> {
>>>> struct f2fs_inode_info *fi = F2FS_I(inode);
>>>> if (!f2fs_compressed_file(inode))
>>>> return true;
>>>> - if (S_ISREG(inode->i_mode) && F2FS_HAS_BLOCKS(inode))
>>>> + if (inode_has_data(inode))
>>>> return false;
>>>> fi->i_flags &= ~F2FS_COMPR_FL;
>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>>> index 1a3c29a9a6a0..8af4b29c3e1a 100644
>>>> --- a/fs/f2fs/file.c
>>>> +++ b/fs/f2fs/file.c
>>>> @@ -1922,8 +1922,7 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
>>>> f2fs_down_write(&F2FS_I(inode)->i_sem);
>>>> if (!f2fs_may_compress(inode) ||
>>>> - (S_ISREG(inode->i_mode) &&
>>>> - F2FS_HAS_BLOCKS(inode))) {
>>>> + inode_has_data(inode)) {
>>>> f2fs_up_write(&F2FS_I(inode)->i_sem);
>>>> return -EINVAL;
>>>> }
>>>> @@ -3996,7 +3995,7 @@ static int f2fs_ioc_set_compress_option(struct file *filp, unsigned long arg)
>>>> goto out;
>>>> }
>>>> - if (F2FS_HAS_BLOCKS(inode)) {
>>>> + if (inode_has_data(inode)) {
>>>> ret = -EFBIG;
>>>> goto out;
>>>> }
>>>> --
>>>> 2.40.1
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