Messages in this thread | | | Date | Thu, 11 Jan 2024 11:07:24 +0800 | Subject | Re: [PATCH 5/6] f2fs: fix to restrict condition of compress inode conversion | From | Chao Yu <> |
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On 2024/1/3 6:54, Jaegeuk Kim wrote: > On 12/28, Chao Yu wrote: >> 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); > > So, needing i_sem for disabling it on mmapped file? It seems i_size would not > be enough?
Agreed, let me update the patch.
Thanks,
> >> >> Thanks, >> >>> >>>> - set_compress_context >>>> >>>> Thanks, >>>> >>>>> >>>>>> >>>>>> Fixes: 4c8ff7095bef ("f2fs: support data compression") >>>>>> Signed-off-by: Chao Yu <chao@kernel.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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