Messages in this thread Patch in this message | | | Subject | Re: [PATCH v3] f2fs: submit cached bio to avoid endless PageWriteback | From | Chao Yu <> | Date | Tue, 18 Sep 2018 10:14:21 +0800 |
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On 2018/9/18 10:02, Jaegeuk Kim wrote: > On 09/18, Chao Yu wrote: >> On 2018/9/18 9:37, Jaegeuk Kim wrote: >>> On 09/18, Chao Yu wrote: >>>> On 2018/9/18 9:04, Jaegeuk Kim wrote: >>>>> On 09/13, Chao Yu wrote: >>>>>> From: Chao Yu <yuchao0@huawei.com> >>>>>> >>>>>> When migrating encrypted block from background GC thread, we only add >>>>>> them into f2fs inner bio cache, but forget to submit the cached bio, it >>>>>> may cause potential deadlock when we are waiting page writebacked, fix >>>>>> it. >>>>>> >>>>>> Signed-off-by: Chao Yu <yuchao0@huawei.com> >>>>>> --- >>>>>> v3: >>>>>> clean up codes suggested by Jaegeuk. >>>>>> fs/f2fs/f2fs.h | 2 +- >>>>>> fs/f2fs/gc.c | 71 +++++++++++++++++++++++++++++++++++--------------- >>>>>> fs/f2fs/node.c | 13 ++++++--- >>>>>> 3 files changed, 61 insertions(+), 25 deletions(-) >>>>>> >>>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >>>>>> index b676b82312e0..917b2ca76aac 100644 >>>>>> --- a/fs/f2fs/f2fs.h >>>>>> +++ b/fs/f2fs/f2fs.h >>>>>> @@ -2869,7 +2869,7 @@ struct page *f2fs_new_node_page(struct dnode_of_data *dn, unsigned int ofs); >>>>>> void f2fs_ra_node_page(struct f2fs_sb_info *sbi, nid_t nid); >>>>>> struct page *f2fs_get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid); >>>>>> struct page *f2fs_get_node_page_ra(struct page *parent, int start); >>>>>> -void f2fs_move_node_page(struct page *node_page, int gc_type); >>>>>> +int f2fs_move_node_page(struct page *node_page, int gc_type); >>>>>> int f2fs_fsync_node_pages(struct f2fs_sb_info *sbi, struct inode *inode, >>>>>> struct writeback_control *wbc, bool atomic, >>>>>> unsigned int *seq_id); >>>>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c >>>>>> index a4c1a419611d..f57622cfe058 100644 >>>>>> --- a/fs/f2fs/gc.c >>>>>> +++ b/fs/f2fs/gc.c >>>>>> @@ -461,7 +461,7 @@ static int check_valid_map(struct f2fs_sb_info *sbi, >>>>>> * On validity, copy that node with cold status, otherwise (invalid node) >>>>>> * ignore that. >>>>>> */ >>>>>> -static void gc_node_segment(struct f2fs_sb_info *sbi, >>>>>> +static int gc_node_segment(struct f2fs_sb_info *sbi, >>>>>> struct f2fs_summary *sum, unsigned int segno, int gc_type) >>>>>> { >>>>>> struct f2fs_summary *entry; >>>>>> @@ -469,6 +469,7 @@ static void gc_node_segment(struct f2fs_sb_info *sbi, >>>>>> int off; >>>>>> int phase = 0; >>>>>> bool fggc = (gc_type == FG_GC); >>>>>> + int submitted = 0; >>>>>> >>>>>> start_addr = START_BLOCK(sbi, segno); >>>>>> >>>>>> @@ -482,10 +483,11 @@ static void gc_node_segment(struct f2fs_sb_info *sbi, >>>>>> nid_t nid = le32_to_cpu(entry->nid); >>>>>> struct page *node_page; >>>>>> struct node_info ni; >>>>>> + int err; >>>>>> >>>>>> /* stop BG_GC if there is not enough free sections. */ >>>>>> if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) >>>>>> - return; >>>>>> + return submitted; >>>>>> >>>>>> if (check_valid_map(sbi, segno, off) == 0) >>>>>> continue; >>>>>> @@ -522,7 +524,9 @@ static void gc_node_segment(struct f2fs_sb_info *sbi, >>>>>> continue; >>>>>> } >>>>>> >>>>>> - f2fs_move_node_page(node_page, gc_type); >>>>>> + err = f2fs_move_node_page(node_page, gc_type); >>>>>> + if (!err && gc_type == FG_GC) >>>>>> + submitted++; >>>>>> stat_inc_node_blk_count(sbi, 1, gc_type); >>>>>> } >>>>>> >>>>>> @@ -531,6 +535,7 @@ static void gc_node_segment(struct f2fs_sb_info *sbi, >>>>>> >>>>>> if (fggc) >>>>>> atomic_dec(&sbi->wb_sync_req[NODE]); >>>>>> + return submitted; >>>>>> } >>>>>> >>>>>> /* >>>>>> @@ -666,7 +671,7 @@ static int ra_data_block(struct inode *inode, pgoff_t index) >>>>>> * Move data block via META_MAPPING while keeping locked data page. >>>>>> * This can be used to move blocks, aka LBAs, directly on disk. >>>>>> */ >>>>>> -static void move_data_block(struct inode *inode, block_t bidx, >>>>>> +static int move_data_block(struct inode *inode, block_t bidx, >>>>>> int gc_type, unsigned int segno, int off) >>>>> >>>>> We don't need to submit IOs in this case. >>>> >>>> Actually, previously, we missed to submit IOs for encrypted block only in >>>> BGGC, so we fix to submit for this case, all other codes are cleanups. Right? >>> >>> The move_data_block migrates encrypted blocks all the time with meta page IOs. >>> I don't know what you're saying about BGGC. >> >> In move_data_block(), we use f2fs_submit_page_write() to add encrypted page >> in to sbi->write_io[META].bio cache, so before exit GC, we need to submit >> this cache by f2fs_submit_merged_write(), otherwise bio with encrypted page >> will be cached in sbi->write_io[META].bio for long time, since we only >> submmit this bio cache in foreground GC. >> >> if (gc_type == FG_GC) >> f2fs_submit_merged_write(sbi, >> (type == SUM_TYPE_NODE) ? NODE : DATA); > > Does this issue pending META IOs? I think META won't block any NODE/DATA > pages. Moreover checkpoint or reading the moved block make the IOs be flushed, > so it doesn't hurt the consistency.
I just guess below endless waiting for page writeback is cased by this case
-000|__switch_to()
-001|__schedule()
-002|need_resched(inline)
-002|schedule()
-003|schedule_timeout()
-004|get_current(inline)
-004|io_schedule_timeout()
-005|bit_wait_io()
-006|__wait_on_bit()
-007|wait_on_page_bit()
-008|PageWriteback(inline)
-008|wait_on_page_writeback(inline)
-008|__filemap_fdatawait_range()
-009|filemap_fdatawait_keep_errors()
-010|sync_inodes_sb()
-011|__sync_filesystem(inline)
-011|sync_filesystem()
-012|generic_shutdown_super()
-013|kill_block_super()
-014|kill_f2fs_super()
-015|deactivate_locked_super()
-016|deactivate_super()
-017|mnt_free_id(inline)
-017|cleanup_mnt()
-018|__cleanup_mnt()
-019|task_work_run()
-020|do_notify_resume()
-021|work_pending(asm)
-->|exception
-022|NUX:0x539E58(asm)
---|end of frame
> >> >>> >>>> >>>> Thanks, >>>> >>>>> >>>>>> { >>>>>> struct f2fs_io_info fio = { >>>>>> @@ -685,25 +690,29 @@ static void move_data_block(struct inode *inode, block_t bidx, >>>>>> struct node_info ni; >>>>>> struct page *page, *mpage; >>>>>> block_t newaddr; >>>>>> - int err; >>>>>> + int err = 0; >>>>>> bool lfs_mode = test_opt(fio.sbi, LFS); >>>>>> >>>>>> /* do not read out */ >>>>>> page = f2fs_grab_cache_page(inode->i_mapping, bidx, false); >>>>>> if (!page) >>>>>> - return; >>>>>> + return -ENOMEM; >>>>>> >>>>>> - if (!check_valid_map(F2FS_I_SB(inode), segno, off)) >>>>>> + if (!check_valid_map(F2FS_I_SB(inode), segno, off)) { >>>>>> + err = -ENOENT; >>>>>> 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]++; >>>>>> + err = -EAGAIN; >>>>>> goto out; >>>>>> } >>>>>> >>>>>> if (f2fs_is_pinned_file(inode)) { >>>>>> f2fs_pin_file_control(inode, true); >>>>>> + err = -EAGAIN; >>>>>> goto out; >>>>>> } >>>>>> >>>>>> @@ -714,6 +723,7 @@ static void move_data_block(struct inode *inode, block_t bidx, >>>>>> >>>>>> if (unlikely(dn.data_blkaddr == NULL_ADDR)) { >>>>>> ClearPageUptodate(page); >>>>>> + err = -ENOENT; >>>>>> goto put_out; >>>>>> } >>>>>> >>>>>> @@ -796,6 +806,7 @@ static void move_data_block(struct inode *inode, block_t bidx, >>>>>> fio.new_blkaddr = newaddr; >>>>>> f2fs_submit_page_write(&fio); >>>>>> if (fio.retry) { >>>>>> + err = -EAGAIN; >>>>>> if (PageWriteback(fio.encrypted_page)) >>>>>> end_page_writeback(fio.encrypted_page); >>>>>> goto put_page_out; >>>>>> @@ -819,34 +830,42 @@ static void move_data_block(struct inode *inode, block_t bidx, >>>>>> f2fs_put_dnode(&dn); >>>>>> out: >>>>>> f2fs_put_page(page, 1); >>>>>> + return err; >>>>>> } >>>>>> >>>>>> -static void move_data_page(struct inode *inode, block_t bidx, int gc_type, >>>>>> +static int move_data_page(struct inode *inode, block_t bidx, int gc_type, >>>>>> unsigned int segno, int off) >>>>>> { >>>>>> struct page *page; >>>>>> + int err = 0; >>>>>> >>>>>> page = f2fs_get_lock_data_page(inode, bidx, true); >>>>>> if (IS_ERR(page)) >>>>>> - return; >>>>>> + return PTR_ERR(page); >>>>>> >>>>>> - if (!check_valid_map(F2FS_I_SB(inode), segno, off)) >>>>>> + if (!check_valid_map(F2FS_I_SB(inode), segno, off)) { >>>>>> + err = -ENOENT; >>>>>> 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]++; >>>>>> + err = -EAGAIN; >>>>>> goto out; >>>>>> } >>>>>> if (f2fs_is_pinned_file(inode)) { >>>>>> if (gc_type == FG_GC) >>>>>> f2fs_pin_file_control(inode, true); >>>>>> + err = -EAGAIN; >>>>>> goto out; >>>>>> } >>>>>> >>>>>> if (gc_type == BG_GC) { >>>>>> - if (PageWriteback(page)) >>>>>> + if (PageWriteback(page)) { >>>>>> + err = -EAGAIN; >>>>>> goto out; >>>>>> + } >>>>>> set_page_dirty(page); >>>>>> set_cold_data(page); >>>>>> } else { >>>>>> @@ -864,7 +883,6 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type, >>>>>> .io_type = FS_GC_DATA_IO, >>>>>> }; >>>>>> bool is_dirty = PageDirty(page); >>>>>> - int err; >>>>>> >>>>>> retry: >>>>>> set_page_dirty(page); >>>>>> @@ -889,6 +907,7 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type, >>>>>> } >>>>>> out: >>>>>> f2fs_put_page(page, 1); >>>>>> + return err; >>>>>> } >>>>>> >>>>>> /* >>>>>> @@ -898,7 +917,7 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type, >>>>>> * If the parent node is not valid or the data block address is different, >>>>>> * the victim data block is ignored. >>>>>> */ >>>>>> -static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, >>>>>> +static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, >>>>>> struct gc_inode_list *gc_list, unsigned int segno, int gc_type) >>>>>> { >>>>>> struct super_block *sb = sbi->sb; >>>>>> @@ -906,6 +925,7 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, >>>>>> block_t start_addr; >>>>>> int off; >>>>>> int phase = 0; >>>>>> + int submitted = 0; >>>>>> >>>>>> start_addr = START_BLOCK(sbi, segno); >>>>>> >>>>>> @@ -922,7 +942,7 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, >>>>>> >>>>>> /* stop BG_GC if there is not enough free sections. */ >>>>>> if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) >>>>>> - return; >>>>>> + return submitted; >>>>>> >>>>>> if (check_valid_map(sbi, segno, off) == 0) >>>>>> continue; >>>>>> @@ -994,6 +1014,7 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, >>>>>> if (inode) { >>>>>> struct f2fs_inode_info *fi = F2FS_I(inode); >>>>>> bool locked = false; >>>>>> + int err; >>>>>> >>>>>> if (S_ISREG(inode->i_mode)) { >>>>>> if (!down_write_trylock(&fi->i_gc_rwsem[READ])) >>>>>> @@ -1013,12 +1034,16 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, >>>>>> start_bidx = f2fs_start_bidx_of_node(nofs, inode) >>>>>> + ofs_in_node; >>>>>> if (f2fs_post_read_required(inode)) >>>>>> - move_data_block(inode, start_bidx, gc_type, >>>>>> - segno, off); >>>>>> + err = move_data_block(inode, start_bidx, >>>>>> + gc_type, segno, off); >>>>>> else >>>>>> - move_data_page(inode, start_bidx, gc_type, >>>>>> + err = move_data_page(inode, start_bidx, gc_type, >>>>>> segno, off); >>>>>> >>>>>> + if (!err && (gc_type == FG_GC || >>>>>> + f2fs_post_read_required(inode))) >>>>>> + submitted++; >>>>>> + >>>>>> if (locked) { >>>>>> up_write(&fi->i_gc_rwsem[WRITE]); >>>>>> up_write(&fi->i_gc_rwsem[READ]); >>>>>> @@ -1030,6 +1055,8 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, >>>>>> >>>>>> if (++phase < 5) >>>>>> goto next_step; >>>>>> + >>>>>> + return submitted; >>>>>> } >>>>>> >>>>>> static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim, >>>>>> @@ -1057,6 +1084,7 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi, >>>>>> int seg_freed = 0; >>>>>> unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ? >>>>>> SUM_TYPE_DATA : SUM_TYPE_NODE; >>>>>> + int submitted = 0; >>>>>> >>>>>> /* readahead multi ssa blocks those have contiguous address */ >>>>>> if (sbi->segs_per_sec > 1) >>>>>> @@ -1100,10 +1128,11 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi, >>>>>> * - lock_page(sum_page) >>>>>> */ >>>>>> if (type == SUM_TYPE_NODE) >>>>>> - gc_node_segment(sbi, sum->entries, segno, gc_type); >>>>>> - else >>>>>> - gc_data_segment(sbi, sum->entries, gc_list, segno, >>>>>> + submitted += gc_node_segment(sbi, sum->entries, segno, >>>>>> gc_type); >>>>>> + else >>>>>> + submitted += gc_data_segment(sbi, sum->entries, gc_list, >>>>>> + segno, gc_type); >>>>>> >>>>>> stat_inc_seg_count(sbi, type, gc_type); >>>>>> >>>>>> @@ -1114,7 +1143,7 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi, >>>>>> f2fs_put_page(sum_page, 0); >>>>>> } >>>>>> >>>>>> - if (gc_type == FG_GC) >>>>>> + if (submitted) >>>>>> f2fs_submit_merged_write(sbi, >>>>>> (type == SUM_TYPE_NODE) ? NODE : DATA); >>>>>> >>>>>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c >>>>>> index fa2381c0bc47..214dd6326b4b 100644 >>>>>> --- a/fs/f2fs/node.c >>>>>> +++ b/fs/f2fs/node.c >>>>>> @@ -1584,8 +1584,10 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted, >>>>>> return AOP_WRITEPAGE_ACTIVATE; >>>>>> } >>>>>> >>>>>> -void f2fs_move_node_page(struct page *node_page, int gc_type) >>>>>> +int f2fs_move_node_page(struct page *node_page, int gc_type) >>>>>> { >>>>>> + int err = 0; >>>>>> + >>>>>> if (gc_type == FG_GC) { >>>>>> struct writeback_control wbc = { >>>>>> .sync_mode = WB_SYNC_ALL, >>>>>> @@ -1597,12 +1599,16 @@ void f2fs_move_node_page(struct page *node_page, int gc_type) >>>>>> f2fs_wait_on_page_writeback(node_page, NODE, true); >>>>>> >>>>>> f2fs_bug_on(F2FS_P_SB(node_page), PageWriteback(node_page)); >>>>>> - if (!clear_page_dirty_for_io(node_page)) >>>>>> + if (!clear_page_dirty_for_io(node_page)) { >>>>>> + err = -EAGAIN; >>>>>> goto out_page; >>>>>> + } >>>>>> >>>>>> if (__write_node_page(node_page, false, NULL, >>>>>> - &wbc, false, FS_GC_NODE_IO, NULL)) >>>>>> + &wbc, false, FS_GC_NODE_IO, NULL)) { >>>>>> + err = -EAGAIN; >>>>>> unlock_page(node_page); >>>>>> + } >>>>>> goto release_page; >>>>>> } else { >>>>>> /* set page dirty and write it */ >>>>>> @@ -1613,6 +1619,7 @@ void f2fs_move_node_page(struct page *node_page, int gc_type) >>>>>> unlock_page(node_page); >>>>>> release_page: >>>>>> f2fs_put_page(node_page, 0); >>>>>> + return err; >>>>>> } >>>>>> >>>>>> static int f2fs_write_node_page(struct page *page, >>>>>> -- >>>>>> 2.18.0 >>>>> >>>>> . >>>>> >>> >>> . >>> > > . >
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