Messages in this thread | | | Subject | Re: [PATCH 3/5] f2fs: avoid stucking GC due to atomic write | From | Chao Yu <> | Date | Fri, 20 Apr 2018 11:22:18 +0800 |
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On 2018/4/20 11:12, Jaegeuk Kim wrote: > On 04/18, Chao Yu wrote: >> f2fs doesn't allow abuse on atomic write class interface, so except >> limiting in-mem pages' total memory usage capacity, we need to limit >> atomic-write usage as well when filesystem is seriously fragmented, >> otherwise we may run into infinite loop during foreground GC because >> target blocks in victim segment are belong to atomic opened file for >> long time. >> >> Now, we will detect failure due to atomic write in foreground GC, if >> the count exceeds threshold, we will drop all atomic written data in >> cache, by this, I expect it can keep our system running safely to >> prevent Dos attack. >> >> Signed-off-by: Chao Yu <yuchao0@huawei.com> >> --- >> fs/f2fs/f2fs.h | 1 + >> fs/f2fs/file.c | 5 +++++ >> fs/f2fs/gc.c | 27 +++++++++++++++++++++++---- >> fs/f2fs/gc.h | 3 +++ >> fs/f2fs/segment.c | 1 + >> fs/f2fs/segment.h | 2 ++ >> 6 files changed, 35 insertions(+), 4 deletions(-) >> >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >> index c1c3a1d11186..3453288d6a71 100644 >> --- a/fs/f2fs/f2fs.h >> +++ b/fs/f2fs/f2fs.h >> @@ -2249,6 +2249,7 @@ enum { >> FI_EXTRA_ATTR, /* indicate file has extra attribute */ >> FI_PROJ_INHERIT, /* indicate file inherits projectid */ >> FI_PIN_FILE, /* indicate file should not be gced */ >> + FI_ATOMIC_REVOKE_REQUEST,/* indicate atomic committed data has been dropped */ >> }; >> >> static inline void __mark_inode_dirty_flag(struct inode *inode, >> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >> index 7c90ded5a431..cddd9aee1bb2 100644 >> --- a/fs/f2fs/file.c >> +++ b/fs/f2fs/file.c >> @@ -1698,6 +1698,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) >> skip_flush: >> set_inode_flag(inode, FI_HOT_DATA); >> set_inode_flag(inode, FI_ATOMIC_FILE); >> + clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST); >> f2fs_update_time(F2FS_I_SB(inode), REQ_TIME); >> >> F2FS_I(inode)->inmem_task = current; >> @@ -1746,6 +1747,10 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp) >> ret = f2fs_do_sync_file(filp, 0, LLONG_MAX, 1, false); >> } >> err_out: >> + if (is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST)) { >> + clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST); >> + ret = -EINVAL; >> + } >> up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); >> inode_unlock(inode); >> mnt_drop_write_file(filp); >> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c >> index bfb7a4a3a929..495876ca62b6 100644 >> --- a/fs/f2fs/gc.c >> +++ b/fs/f2fs/gc.c >> @@ -135,6 +135,8 @@ int start_gc_thread(struct f2fs_sb_info *sbi) >> gc_th->gc_urgent = 0; >> gc_th->gc_wake= 0; >> >> + gc_th->atomic_file = 0; >> + >> sbi->gc_thread = gc_th; >> init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head); >> sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi, >> @@ -603,7 +605,7 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, >> * This can be used to move blocks, aka LBAs, directly on disk. >> */ >> static void move_data_block(struct inode *inode, block_t bidx, >> - unsigned int segno, int off) >> + int gc_type, unsigned int segno, int off) >> { >> struct f2fs_io_info fio = { >> .sbi = F2FS_I_SB(inode), >> @@ -630,8 +632,10 @@ static void move_data_block(struct inode *inode, block_t bidx, >> if (!check_valid_map(F2FS_I_SB(inode), segno, off)) >> goto out; >> >> - if (f2fs_is_atomic_file(inode)) >> + if (f2fs_is_atomic_file(inode)) { >> + F2FS_I_SB(inode)->gc_thread->atomic_file++; >> goto out; >> + } >> >> if (f2fs_is_pinned_file(inode)) { >> f2fs_pin_file_control(inode, true); >> @@ -737,8 +741,10 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type, >> if (!check_valid_map(F2FS_I_SB(inode), segno, off)) >> goto out; >> >> - if (f2fs_is_atomic_file(inode)) >> + if (f2fs_is_atomic_file(inode)) { >> + F2FS_I_SB(inode)->gc_thread->atomic_file++; >> goto out; >> + } >> if (f2fs_is_pinned_file(inode)) { >> if (gc_type == FG_GC) >> f2fs_pin_file_control(inode, true); >> @@ -900,7 +906,8 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, >> start_bidx = start_bidx_of_node(nofs, inode) >> + ofs_in_node; >> if (f2fs_encrypted_file(inode)) >> - move_data_block(inode, start_bidx, segno, off); >> + move_data_block(inode, start_bidx, gc_type, >> + segno, off); >> else >> move_data_page(inode, start_bidx, gc_type, >> segno, off); >> @@ -1017,6 +1024,8 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, >> .ilist = LIST_HEAD_INIT(gc_list.ilist), >> .iroot = RADIX_TREE_INIT(GFP_NOFS), >> }; >> + unsigned int last_atomic_file = sbi->gc_thread->atomic_file; >> + unsigned int skipped_round = 0, round = 0; >> >> trace_f2fs_gc_begin(sbi->sb, sync, background, >> get_pages(sbi, F2FS_DIRTY_NODES), >> @@ -1068,11 +1077,21 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, >> sec_freed++; >> total_freed += seg_freed; >> >> + if (gc_type == FG_GC) { >> + if (sbi->gc_thread->atomic_file > last_atomic_file) >> + skipped_round++; >> + last_atomic_file = sbi->gc_thread->atomic_file; > > How about resetting ->atomic_file to zero?
Since we will show this stat number through sysfs entry, it'd better to keep its data?
Thanks,
> >> + round++; >> + } >> + >> if (gc_type == FG_GC) >> sbi->cur_victim_sec = NULL_SEGNO; >> >> if (!sync) { >> if (has_not_enough_free_secs(sbi, sec_freed, 0)) { >> + if (skipped_round > MAX_SKIP_ATOMIC_COUNT && >> + skipped_round * 2 >= round) >> + drop_inmem_pages_all(sbi); >> segno = NULL_SEGNO; >> goto gc_more; >> } >> diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h >> index b0045d4c8d1e..bc1d21d46ae7 100644 >> --- a/fs/f2fs/gc.h >> +++ b/fs/f2fs/gc.h >> @@ -39,6 +39,9 @@ struct f2fs_gc_kthread { >> unsigned int gc_idle; >> unsigned int gc_urgent; >> unsigned int gc_wake; >> + >> + /* for stuck statistic */ >> + unsigned int atomic_file; >> }; >> >> struct gc_inode_list { >> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >> index d809f731bfd1..831cefa088bc 100644 >> --- a/fs/f2fs/segment.c >> +++ b/fs/f2fs/segment.c >> @@ -287,6 +287,7 @@ void drop_inmem_pages_all(struct f2fs_sb_info *sbi) >> spin_unlock(&sbi->inode_lock[ATOMIC_FILE]); >> >> if (inode) { >> + set_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST); >> drop_inmem_pages(inode); >> iput(inode); >> } >> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h >> index 492ad0c86fa9..7702b054689c 100644 >> --- a/fs/f2fs/segment.h >> +++ b/fs/f2fs/segment.h >> @@ -215,6 +215,8 @@ struct segment_allocation { >> #define IS_DUMMY_WRITTEN_PAGE(page) \ >> (page_private(page) == (unsigned long)DUMMY_WRITTEN_PAGE) >> >> +#define MAX_SKIP_ATOMIC_COUNT 16 >> + >> struct inmem_pages { >> struct list_head list; >> struct page *page; >> -- >> 2.15.0.55.gc2ece9dc4de6 > > . >
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