Messages in this thread Patch in this message | | | Date | Sat, 28 Jul 2018 22:51:05 -0700 | From | Jaegeuk Kim <> | Subject | Re: [f2fs-dev] [PATCH 1/3] f2fs: turn off atomic writes when deteting abnormal behaviors |
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On 07/27, Chao Yu wrote: > On 2018/7/27 17:17, Jaegeuk Kim wrote: > > On 07/23, Chao Yu wrote: > >> On 2018/7/23 21:03, Jaegeuk Kim wrote: > >>> On 07/16, Chao Yu wrote: > >>>> On 2018/7/15 9:11, Jaegeuk Kim wrote: > >>>>> In order to prevent abusing atomic writes by abnormal users, we've added a > >>>>> threshold, 20% over memory footprint, which disallows further atomic writes. > >>>>> Previously, however, SQLite doesn't know the files became normal, so that > >>>>> it could write stale data and commit on revoked normal database file. > >>>>> > >>>>> Once f2fs detects such the abnormal behavior, this patch simply disables > >>>>> all the atomic operations such as: > >>>>> - write_begin() gives EINVAL to avoid stale data writes, and SQLite will call > >>>>> F2FS_IOC_ABORT_VOLATILE_WRITE to notify aborting the transaction, > >>>>> - F2FS_IOC_START_ATOMIC_WRITE gives EINVAL for SQLite to fall back normal > >>>>> journal_mode, > >>>>> - F2FS_IOC_COMMIT_ATOMIC_WRITE gives EINVAL, if the file was revoked, so that > >>>>> Framework retries to submit the transaction given propagated SQLite error. > >>>>> > >>>>> Note that, this patch also turns off atomic operations, if foreground GC tries > >>>>> to move atomic files too frequently. > >>>> > >>>> Well, how about just keeping original implementation: shutdown atomic write for > >>>> those files which are really affect fggc? Since intention of the original > >>>> behavior is targeting to abnormal atomic write usage, e.g. open atomic_write > >>>> file for very long time, then fggc will be blocked each time when moving its > >>>> block. So shutdown it, fggc will recover. > >>> > >>> The point here is stopping sqlite to keep going wrong data writes even after > >>> we already revoked blocks. > >> > >> Yes, that's correct, what I mean is that if we can do that with smaller > >> granularity like just revoke blocks for file which is blocking fggc, it will > >> affect system/sqlite flow much less than forcing closing all atomic_write. > > > > How about this? > > Yes, it looks good to me. :) > > > > > From 64d2becb82a496c2e2c04abeed42efa3b401ee20 Mon Sep 17 00:00:00 2001 > > From: Jaegeuk Kim <jaegeuk@kernel.org> > > Date: Fri, 27 Jul 2018 18:15:11 +0900 > > Subject: [PATCH] f2fs: don't allow any writes on aborted atomic writes > > > > In order to prevent abusing atomic writes by abnormal users, we've added a > > threshold, 20% over memory footprint, which disallows further atomic writes. > > Previously, however, SQLite doesn't know the files became normal, so that > > it could write stale data and commit on revoked normal database file. > > > > Once f2fs detects such the abnormal behavior, this patch tries to avoid further > > writes in write_begin(). > > > > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> > > Reviewed-by: Chao Yu <yuchao0@huawei.com> > > Thanks, > > > --- > > fs/f2fs/data.c | 3 ++- > > fs/f2fs/file.c | 7 ++++++- > > 2 files changed, 8 insertions(+), 2 deletions(-) > > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > > index 22dd00c6e241..02ec2603725f 100644 > > --- a/fs/f2fs/data.c > > +++ b/fs/f2fs/data.c > > @@ -2295,7 +2295,8 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping, > > trace_f2fs_write_begin(inode, pos, len, flags); > > > > if (f2fs_is_atomic_file(inode) && > > - !f2fs_available_free_memory(sbi, INMEM_PAGES)) { > > + (is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST) || > > + !f2fs_available_free_memory(sbi, INMEM_PAGES))) {
if ((f2fs_is_atomic_file(inode) && !f2fs_available_free_memory(sbi, INMEM_PAGES)) || is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST)) {
-- Fixed wrong condition.
> > err = -ENOMEM; > > drop_atomic = true; > > goto fail; > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > > index ff2cb8fb6934..c2c47f3248c4 100644 > > --- a/fs/f2fs/file.c > > +++ b/fs/f2fs/file.c > > @@ -1708,8 +1708,11 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) > > > > down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); > > > > - if (f2fs_is_atomic_file(inode)) > > + if (f2fs_is_atomic_file(inode)) { > > + if (is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST)) > > + ret = -EINVAL; > > goto out; > > + } > > > > ret = f2fs_convert_inline_inode(inode); > > if (ret) > > @@ -1871,6 +1874,8 @@ static int f2fs_ioc_abort_volatile_write(struct file *filp) > > ret = f2fs_do_sync_file(filp, 0, LLONG_MAX, 0, true); > > } > > > > + clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST); > > + > > inode_unlock(inode); > > > > mnt_drop_write_file(filp); > >
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