Messages in this thread | | | Date | Tue, 2 Jan 2024 14:54:31 -0800 | From | Jaegeuk Kim <> | Subject | Re: [PATCH 5/6] f2fs: fix to restrict condition of compress inode conversion |
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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?
> > 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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