From: Chao Yu yuchao0@huawei.com
[ Upstream commit 493720a4854343b7c3fe100cda6a3a2c3f8d4b5d ]
Lei Li reported a issue: if foreground operations are frequent, background checkpoint may be always skipped due to below check, result in losing more data after sudden power-cut.
f2fs_balance_fs_bg() ... if (!is_idle(sbi, REQ_TIME) && (!excess_dirty_nats(sbi) && !excess_dirty_nodes(sbi))) return;
E.g: cp_interval = 5 second idle_interval = 2 second foreground operation interval = 1 second (append 1 byte per second into file)
In such case, no matter when it calls f2fs_balance_fs_bg(), is_idle(, REQ_TIME) returns false, result in skipping background checkpoint.
This patch changes as below to make trigger condition being more reasonable: - trigger sync_fs() if dirty_{nats,nodes} and prefree segs exceeds threshold; - skip triggering sync_fs() if there is any background inflight IO or there is foreground operation recently and meanwhile cp_rwsem is being held by someone;
Reported-by: Lei Li noctis.akm@gmail.com Signed-off-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Stable-dep-of: d80afefb17e0 ("f2fs: fix to account FS_CP_DATA_IO correctly") Signed-off-by: Sasha Levin sashal@kernel.org --- fs/f2fs/f2fs.h | 19 +++++++++++++------ fs/f2fs/segment.c | 47 +++++++++++++++++++++++++++-------------------- 2 files changed, 40 insertions(+), 26 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index dbe9fcef07e3..70fec13d35b7 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -2426,24 +2426,31 @@ static inline void *f2fs_kmem_cache_alloc(struct kmem_cache *cachep, return entry; }
-static inline bool is_idle(struct f2fs_sb_info *sbi, int type) +static inline bool is_inflight_io(struct f2fs_sb_info *sbi, int type) { - if (sbi->gc_mode == GC_URGENT_HIGH) - return true; - if (get_pages(sbi, F2FS_RD_DATA) || get_pages(sbi, F2FS_RD_NODE) || get_pages(sbi, F2FS_RD_META) || get_pages(sbi, F2FS_WB_DATA) || get_pages(sbi, F2FS_WB_CP_DATA) || get_pages(sbi, F2FS_DIO_READ) || get_pages(sbi, F2FS_DIO_WRITE)) - return false; + return true;
if (type != DISCARD_TIME && SM_I(sbi) && SM_I(sbi)->dcc_info && atomic_read(&SM_I(sbi)->dcc_info->queued_discard)) - return false; + return true;
if (SM_I(sbi) && SM_I(sbi)->fcc_info && atomic_read(&SM_I(sbi)->fcc_info->queued_flush)) + return true; + return false; +} + +static inline bool is_idle(struct f2fs_sb_info *sbi, int type) +{ + if (sbi->gc_mode == GC_URGENT_HIGH) + return true; + + if (is_inflight_io(sbi, type)) return false;
if (sbi->gc_mode == GC_URGENT_LOW && diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 19224e7d2ad0..173161f1ced0 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -536,31 +536,38 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi, bool from_bg) else f2fs_build_free_nids(sbi, false, false);
- if (!is_idle(sbi, REQ_TIME) && - (!excess_dirty_nats(sbi) && !excess_dirty_nodes(sbi))) + if (excess_dirty_nats(sbi) || excess_dirty_nodes(sbi) || + excess_prefree_segs(sbi)) + goto do_sync; + + /* there is background inflight IO or foreground operation recently */ + if (is_inflight_io(sbi, REQ_TIME) || + (!f2fs_time_over(sbi, REQ_TIME) && rwsem_is_locked(&sbi->cp_rwsem))) return;
+ /* exceed periodical checkpoint timeout threshold */ + if (f2fs_time_over(sbi, CP_TIME)) + goto do_sync; + /* checkpoint is the only way to shrink partial cached entries */ - if (!f2fs_available_free_memory(sbi, NAT_ENTRIES) || - !f2fs_available_free_memory(sbi, INO_ENTRIES) || - excess_prefree_segs(sbi) || - excess_dirty_nats(sbi) || - excess_dirty_nodes(sbi) || - f2fs_time_over(sbi, CP_TIME)) { - if (test_opt(sbi, DATA_FLUSH) && from_bg) { - struct blk_plug plug; - - mutex_lock(&sbi->flush_lock); - - blk_start_plug(&plug); - f2fs_sync_dirty_inodes(sbi, FILE_INODE); - blk_finish_plug(&plug); + if (f2fs_available_free_memory(sbi, NAT_ENTRIES) || + f2fs_available_free_memory(sbi, INO_ENTRIES)) + return;
- mutex_unlock(&sbi->flush_lock); - } - f2fs_sync_fs(sbi->sb, true); - stat_inc_bg_cp_count(sbi->stat_info); +do_sync: + if (test_opt(sbi, DATA_FLUSH) && from_bg) { + struct blk_plug plug; + + mutex_lock(&sbi->flush_lock); + + blk_start_plug(&plug); + f2fs_sync_dirty_inodes(sbi, FILE_INODE); + blk_finish_plug(&plug); + + mutex_unlock(&sbi->flush_lock); } + f2fs_sync_fs(sbi->sb, true); + stat_inc_bg_cp_count(sbi->stat_info); }
static int __submit_flush_wait(struct f2fs_sb_info *sbi,