Commits
Jaegeuk Kim committed 743b620cb05
f2fs: avoid infinite GC loop due to stale atomic files If committing atomic pages is failed when doing f2fs_do_sync_file(), we can get commited pages but atomic_file being still set like: - inmem: 0, atomic IO: 4 (Max. 10), volatile IO: 0 (Max. 0) If GC selects this block, we can get an infinite loop like this: f2fs_submit_page_bio: dev = (253,7), ino = 2, page_index = 0x2359a8, oldaddr = 0x2359a8, newaddr = 0x2359a8, rw = READ(), type = COLD_DATA f2fs_submit_read_bio: dev = (253,7)/(253,7), rw = READ(), DATA, sector = 18533696, size = 4096 f2fs_get_victim: dev = (253,7), type = No TYPE, policy = (Foreground GC, LFS-mode, Greedy), victim = 4355, cost = 1, ofs_unit = 1, pre_victim_secno = 4355, prefree = 0, free = 234 f2fs_iget: dev = (253,7), ino = 6247, pino = 5845, i_mode = 0x81b0, i_size = 319488, i_nlink = 1, i_blocks = 624, i_advise = 0x2c f2fs_submit_page_bio: dev = (253,7), ino = 2, page_index = 0x2359a8, oldaddr = 0x2359a8, newaddr = 0x2359a8, rw = READ(), type = COLD_DATA f2fs_submit_read_bio: dev = (253,7)/(253,7), rw = READ(), DATA, sector = 18533696, size = 4096 f2fs_get_victim: dev = (253,7), type = No TYPE, policy = (Foreground GC, LFS-mode, Greedy), victim = 4355, cost = 1, ofs_unit = 1, pre_victim_secno = 4355, prefree = 0, free = 234 f2fs_iget: dev = (253,7), ino = 6247, pino = 5845, i_mode = 0x81b0, i_size = 319488, i_nlink = 1, i_blocks = 624, i_advise = 0x2c In that moment, we can observe: [Before] Try to move 5084219 blocks (BG: 384508) - data blocks : 4962373 (274483) - node blocks : 121846 (110025) Skipped : atomic write 4534686 (10) [After] Try to move 5088973 blocks (BG: 384508) - data blocks : 4967127 (274483) - node blocks : 121846 (110025) Skipped : atomic write 4539440 (10) So, refactor atomic_write flow like this: 1. start_atomic_write - add inmem_list and set atomic_file 2. write() - register it in inmem_pages 3. commit_atomic_write - if no error, f2fs_drop_inmem_pages() - f2fs_commit_inmme_pages() failed : __revoked_inmem_pages() was done - f2fs_do_sync_file failed : abort_atomic_write later 4. abort_atomic_write - f2fs_drop_inmem_pages 5. f2fs_drop_inmem_pages - clear atomic_file - remove inmem_list Based on this change, when GC fails to move block in atomic_file, f2fs_drop_inmem_pages_all() can call f2fs_drop_inmem_pages(). Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>