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Date: Mon, 23 Jul 2018 22:03:46 +0900 From: Jaegeuk Kim <jaegeuk@...nel.org> To: Chao Yu <yuchao0@...wei.com> Cc: linux-kernel@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net Subject: Re: [PATCH 1/3] f2fs: turn off atomic writes when deteting abnormal behaviors 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 - F2FS_IOC_COMMIT_ATOMIC_WRITE gives EINVAL, if the file was revoked, so that 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. Thanks, > > Thanks, > > > > > Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org> > > --- > > fs/f2fs/data.c | 7 ++++--- > > fs/f2fs/f2fs.h | 4 ++-- > > fs/f2fs/file.c | 6 +++++- > > fs/f2fs/gc.c | 4 +--- > > fs/f2fs/segment.c | 21 +++++++++++---------- > > 5 files changed, 23 insertions(+), 19 deletions(-) > > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > > index 5e53d210e222..c9e75aa61c24 100644 > > --- a/fs/f2fs/data.c > > +++ b/fs/f2fs/data.c > > @@ -2247,8 +2247,9 @@ 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)) { > > - err = -ENOMEM; > > + (is_sbi_flag_set(sbi, SBI_DISABLE_ATOMIC_WRITE) || > > + !f2fs_available_free_memory(sbi, INMEM_PAGES))) { > > + err = -EINVAL; > > drop_atomic = true; > > goto fail; > > } > > @@ -2331,7 +2332,7 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping, > > f2fs_put_page(page, 1); > > f2fs_write_failed(mapping, pos + len); > > if (drop_atomic) > > - f2fs_drop_inmem_pages_all(sbi, false); > > + f2fs_disable_atomic_write(sbi); > > return err; > > } > > > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > > index 4d8b1de83143..1d5c8d543eda 100644 > > --- a/fs/f2fs/f2fs.h > > +++ b/fs/f2fs/f2fs.h > > @@ -621,7 +621,6 @@ enum { > > > > enum { > > GC_FAILURE_PIN, > > - GC_FAILURE_ATOMIC, > > MAX_GC_FAILURE > > }; > > > > @@ -1066,6 +1065,7 @@ enum { > > SBI_POR_DOING, /* recovery is doing or not */ > > SBI_NEED_SB_WRITE, /* need to recover superblock */ > > SBI_NEED_CP, /* need to checkpoint */ > > + SBI_DISABLE_ATOMIC_WRITE, /* turn off atomic write */ > > }; > > > > enum { > > @@ -2833,7 +2833,7 @@ void f2fs_destroy_node_manager_caches(void); > > */ > > bool f2fs_need_SSR(struct f2fs_sb_info *sbi); > > void f2fs_register_inmem_page(struct inode *inode, struct page *page); > > -void f2fs_drop_inmem_pages_all(struct f2fs_sb_info *sbi, bool gc_failure); > > +void f2fs_disable_atomic_write(struct f2fs_sb_info *sbi); > > void f2fs_drop_inmem_pages(struct inode *inode); > > void f2fs_drop_inmem_page(struct inode *inode, struct page *page); > > int f2fs_commit_inmem_pages(struct inode *inode); > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > > index 6880c6f78d58..b029a4ed3bb0 100644 > > --- a/fs/f2fs/file.c > > +++ b/fs/f2fs/file.c > > @@ -1682,6 +1682,9 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) > > if (!S_ISREG(inode->i_mode)) > > return -EINVAL; > > > > + if (is_sbi_flag_set(F2FS_I_SB(inode), SBI_DISABLE_ATOMIC_WRITE)) > > + return -EINVAL; > > + > > ret = mnt_want_write_file(filp); > > if (ret) > > return ret; > > @@ -1750,7 +1753,6 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp) > > ret = f2fs_do_sync_file(filp, 0, LLONG_MAX, 0, true); > > if (!ret) { > > clear_inode_flag(inode, FI_ATOMIC_FILE); > > - F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC] = 0; > > stat_dec_atomic_write(inode); > > } > > } else { > > @@ -1853,6 +1855,8 @@ 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); > > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > > index 9093be6e7a7d..6d762f3cdfc7 100644 > > --- a/fs/f2fs/gc.c > > +++ b/fs/f2fs/gc.c > > @@ -629,7 +629,6 @@ static void move_data_block(struct inode *inode, block_t bidx, > > goto out; > > > > if (f2fs_is_atomic_file(inode)) { > > - F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++; > > F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++; > > goto out; > > } > > @@ -745,7 +744,6 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type, > > goto out; > > > > if (f2fs_is_atomic_file(inode)) { > > - F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++; > > F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++; > > goto out; > > } > > @@ -1100,7 +1098,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, > > if (has_not_enough_free_secs(sbi, sec_freed, 0)) { > > if (skipped_round > MAX_SKIP_ATOMIC_COUNT && > > skipped_round * 2 >= round) > > - f2fs_drop_inmem_pages_all(sbi, true); > > + f2fs_disable_atomic_write(sbi); > > segno = NULL_SEGNO; > > goto gc_more; > > } > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > > index 9efce174c51a..05877a2f1894 100644 > > --- a/fs/f2fs/segment.c > > +++ b/fs/f2fs/segment.c > > @@ -274,11 +274,14 @@ static int __revoke_inmem_pages(struct inode *inode, > > return err; > > } > > > > -void f2fs_drop_inmem_pages_all(struct f2fs_sb_info *sbi, bool gc_failure) > > +void f2fs_disable_atomic_write(struct f2fs_sb_info *sbi) > > { > > struct list_head *head = &sbi->inode_list[ATOMIC_FILE]; > > struct inode *inode; > > struct f2fs_inode_info *fi; > > + > > + /* just turn it off */ > > + set_sbi_flag(sbi, SBI_DISABLE_ATOMIC_WRITE); > > next: > > spin_lock(&sbi->inode_lock[ATOMIC_FILE]); > > if (list_empty(head)) { > > @@ -290,17 +293,16 @@ void f2fs_drop_inmem_pages_all(struct f2fs_sb_info *sbi, bool gc_failure) > > spin_unlock(&sbi->inode_lock[ATOMIC_FILE]); > > > > if (inode) { > > - if (gc_failure) { > > - if (fi->i_gc_failures[GC_FAILURE_ATOMIC]) > > - goto drop; > > - goto skip; > > + inode_lock(inode); > > + /* need to check whether it was already revoked */ > > + if (f2fs_is_atomic_file(inode)) { > > + f2fs_drop_inmem_pages(inode); > > + set_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST); > > } > > -drop: > > - set_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST); > > - f2fs_drop_inmem_pages(inode); > > + inode_unlock(inode); > > iput(inode); > > } > > -skip: > > + > > congestion_wait(BLK_RW_ASYNC, HZ/50); > > cond_resched(); > > goto next; > > @@ -320,7 +322,6 @@ void f2fs_drop_inmem_pages(struct inode *inode) > > mutex_unlock(&fi->inmem_lock); > > > > clear_inode_flag(inode, FI_ATOMIC_FILE); > > - fi->i_gc_failures[GC_FAILURE_ATOMIC] = 0; > > stat_dec_atomic_write(inode); > > } > > > >
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