Messages in this thread | | | From | Daeho Jeong <> | Date | Fri, 8 May 2020 16:10:19 +0900 | Subject | Re: [f2fs-dev] [PATCH] f2fs: remove race condition in releasing cblocks |
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Oops,
I will re-check it.
Thanks,
2020년 5월 8일 (금) 오후 4:09, Chao Yu <yuchao0@huawei.com>님이 작성: > > On 2020/5/8 14:58, Daeho Jeong wrote: > > I moved checking i_compr_blocks phrase after calling inode_lock() > > already, because we should check this after writing pages. > > > > So, if it fails to check i_compr_blocks, we need to call inode_unlock(). > > > > Am I missing something? > > After applying this patch, I get this: > > ret = mnt_want_write_file(filp); > if (ret) > return ret; > > if (!F2FS_I(inode)->i_compr_blocks) > goto out; > > f2fs_balance_fs(F2FS_I_SB(inode), true); > > inode_lock(inode); > > > > > 2020년 5월 8일 (금) 오후 3:50, Chao Yu <yuchao0@huawei.com>님이 작성: > >> > >> On 2020/5/8 12:25, Daeho Jeong wrote: > >>> From: Daeho Jeong <daehojeong@google.com> > >>> > >>> Now, if writing pages and releasing compress blocks occur > >>> simultaneously, and releasing cblocks is executed more than one time > >>> to a file, then total block count of filesystem and block count of the > >>> file could be incorrect and damaged. > >>> > >>> We have to execute releasing compress blocks only one time for a file > >>> without being interfered by writepages path. > >>> > >>> Signed-off-by: Daeho Jeong <daehojeong@google.com> > >>> --- > >>> fs/f2fs/file.c | 31 ++++++++++++++++++++++++------- > >>> 1 file changed, 24 insertions(+), 7 deletions(-) > >>> > >>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > >>> index 4aab4b42d8ba..a92bc51b9b28 100644 > >>> --- a/fs/f2fs/file.c > >>> +++ b/fs/f2fs/file.c > >>> @@ -3488,6 +3488,7 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg) > >>> pgoff_t page_idx = 0, last_idx; > >>> unsigned int released_blocks = 0; > >>> int ret; > >>> + int writecount; > >>> > >>> if (!f2fs_sb_has_compression(F2FS_I_SB(inode))) > >>> return -EOPNOTSUPP; > >> > >> Before inode_lock(), there is one case we may jump to out label, in > >> this case, we may unlock inode incorrectly. > >> > >> if (!F2FS_I(inode)->i_compr_blocks) > >> goto out; > >> > >>> - > >>> - inode_unlock(inode); > >>> out: > >>> + inode_unlock(inode); > >>> + > >>> mnt_drop_write_file(filp); > >> > >> Thanks, > > . > >
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