1What: /sys/fs/f2fs/<disk>/gc_max_sleep_time 2Date: July 2013 3Contact: "Namjae Jeon" <namjae.jeon@samsung.com> 4Description: Controls the maximum sleep time for gc_thread. Time 5 is in milliseconds. 6 7What: /sys/fs/f2fs/<disk>/gc_min_sleep_time 8Date: July 2013 9Contact: "Namjae Jeon" <namjae.jeon@samsung.com> 10Description: Controls the minimum sleep time for gc_thread. Time 11 is in milliseconds. 12 13What: /sys/fs/f2fs/<disk>/gc_no_gc_sleep_time 14Date: July 2013 15Contact: "Namjae Jeon" <namjae.jeon@samsung.com> 16Description: Controls the default sleep time for gc_thread. Time 17 is in milliseconds. 18 19What: /sys/fs/f2fs/<disk>/gc_idle 20Date: July 2013 21Contact: "Namjae Jeon" <namjae.jeon@samsung.com> 22Description: Controls the victim selection policy for garbage collection. 23 Setting gc_idle = 0(default) will disable this option. Setting: 24 25 =========== =============================================== 26 gc_idle = 1 will select the Cost Benefit approach & setting 27 gc_idle = 2 will select the greedy approach & setting 28 gc_idle = 3 will select the age-threshold based approach. 29 =========== =============================================== 30 31What: /sys/fs/f2fs/<disk>/reclaim_segments 32Date: October 2013 33Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com> 34Description: This parameter controls the number of prefree segments to be 35 reclaimed. If the number of prefree segments is larger than 36 the number of segments in the proportion to the percentage 37 over total volume size, f2fs tries to conduct checkpoint to 38 reclaim the prefree segments to free segments. 39 By default, 5% over total # of segments. 40 41What: /sys/fs/f2fs/<disk>/main_blkaddr 42Date: November 2019 43Contact: "Ramon Pantin" <pantin@google.com> 44Description: Shows first block address of MAIN area. 45 46What: /sys/fs/f2fs/<disk>/ipu_policy 47Date: November 2013 48Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com> 49Description: Controls the in-place-update policy. 50 updates in f2fs. User can set: 51 52 ===== =============== =================================================== 53 value policy description 54 0x00 DISABLE disable IPU(=default option in LFS mode) 55 0x01 FORCE all the time 56 0x02 SSR if SSR mode is activated 57 0x04 UTIL if FS utilization is over threshold 58 0x08 SSR_UTIL if SSR mode is activated and FS utilization is over 59 threshold 60 0x10 FSYNC activated in fsync path only for high performance 61 flash storages. IPU will be triggered only if the 62 # of dirty pages over min_fsync_blocks. 63 (=default option) 64 0x20 ASYNC do IPU given by asynchronous write requests 65 0x40 NOCACHE disable IPU bio cache 66 0x80 HONOR_OPU_WRITE use OPU write prior to IPU write if inode has 67 FI_OPU_WRITE flag 68 ===== =============== =================================================== 69 70 Refer segment.h for details. 71 72What: /sys/fs/f2fs/<disk>/min_ipu_util 73Date: November 2013 74Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com> 75Description: Controls the FS utilization condition for the in-place-update 76 policies. It is used by F2FS_IPU_UTIL and F2FS_IPU_SSR_UTIL policies. 77 78What: /sys/fs/f2fs/<disk>/min_fsync_blocks 79Date: September 2014 80Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 81Description: Controls the dirty page count condition for the in-place-update 82 policies. 83 84What: /sys/fs/f2fs/<disk>/min_seq_blocks 85Date: August 2018 86Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 87Description: Controls the dirty page count condition for batched sequential 88 writes in writepages. 89 90What: /sys/fs/f2fs/<disk>/min_hot_blocks 91Date: March 2017 92Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 93Description: Controls the dirty page count condition for redefining hot data. 94 95What: /sys/fs/f2fs/<disk>/min_ssr_sections 96Date: October 2017 97Contact: "Chao Yu" <yuchao0@huawei.com> 98Description: Controls the free section threshold to trigger SSR allocation. 99 If this is large, SSR mode will be enabled early. 100 101What: /sys/fs/f2fs/<disk>/max_small_discards 102Date: November 2013 103Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com> 104Description: Controls the issue rate of discard commands that consist of small 105 blocks less than 2MB. The candidates to be discarded are cached during 106 checkpoint, and issued by issue_discard thread after checkpoint. 107 It is enabled by default. 108 109What: /sys/fs/f2fs/<disk>/max_ordered_discard 110Date: October 2022 111Contact: "Yangtao Li" <frank.li@vivo.com> 112Description: Controls the maximum ordered discard, the unit size is one block(4KB). 113 Set it to 16 by default. 114 115What: /sys/fs/f2fs/<disk>/max_discard_request 116Date: December 2021 117Contact: "Konstantin Vyshetsky" <vkon@google.com> 118Description: Controls the number of discards a thread will issue at a time. 119 Higher number will allow the discard thread to finish its work 120 faster, at the cost of higher latency for incoming I/O. 121 122What: /sys/fs/f2fs/<disk>/min_discard_issue_time 123Date: December 2021 124Contact: "Konstantin Vyshetsky" <vkon@google.com> 125Description: Controls the interval the discard thread will wait between 126 issuing discard requests when there are discards to be issued and 127 no I/O aware interruptions occur. 128 129What: /sys/fs/f2fs/<disk>/mid_discard_issue_time 130Date: December 2021 131Contact: "Konstantin Vyshetsky" <vkon@google.com> 132Description: Controls the interval the discard thread will wait between 133 issuing discard requests when there are discards to be issued and 134 an I/O aware interruption occurs. 135 136What: /sys/fs/f2fs/<disk>/max_discard_issue_time 137Date: December 2021 138Contact: "Konstantin Vyshetsky" <vkon@google.com> 139Description: Controls the interval the discard thread will wait when there are 140 no discard operations to be issued. 141 142What: /sys/fs/f2fs/<disk>/discard_granularity 143Date: July 2017 144Contact: "Chao Yu" <yuchao0@huawei.com> 145Description: Controls discard granularity of inner discard thread. Inner thread 146 will not issue discards with size that is smaller than granularity. 147 The unit size is one block(4KB), now only support configuring 148 in range of [1, 512]. Default value is 16. 149 For small devices, default value is 1. 150 151What: /sys/fs/f2fs/<disk>/umount_discard_timeout 152Date: January 2019 153Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 154Description: Set timeout to issue discard commands during umount. 155 Default: 5 secs 156 157What: /sys/fs/f2fs/<disk>/pending_discard 158Date: November 2021 159Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 160Description: Shows the number of pending discard commands in the queue. 161 162What: /sys/fs/f2fs/<disk>/max_victim_search 163Date: January 2014 164Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com> 165Description: Controls the number of trials to find a victim segment 166 when conducting SSR and cleaning operations. The default value 167 is 4096 which covers 8GB block address range. 168 169What: /sys/fs/f2fs/<disk>/migration_granularity 170Date: October 2018 171Contact: "Chao Yu" <yuchao0@huawei.com> 172Description: Controls migration granularity of garbage collection on large 173 section, it can let GC move partial segment{s} of one section 174 in one GC cycle, so that dispersing heavy overhead GC to 175 multiple lightweight one. 176 177What: /sys/fs/f2fs/<disk>/dir_level 178Date: March 2014 179Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com> 180Description: Controls the directory level for large directory. If a 181 directory has a number of files, it can reduce the file lookup 182 latency by increasing this dir_level value. Otherwise, it 183 needs to decrease this value to reduce the space overhead. 184 The default value is 0. 185 186What: /sys/fs/f2fs/<disk>/ram_thresh 187Date: March 2014 188Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com> 189Description: Controls the memory footprint used by free nids and cached 190 nat entries. By default, 1 is set, which indicates 191 10 MB / 1 GB RAM. 192 193What: /sys/fs/f2fs/<disk>/cp_interval 194Date: October 2015 195Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 196Description: Controls the checkpoint timing, set to 60 seconds by default. 197 198What: /sys/fs/f2fs/<disk>/idle_interval 199Date: January 2016 200Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 201Description: Controls the idle timing of system, if there is no FS operation 202 during given interval. 203 Set to 5 seconds by default. 204 205What: /sys/fs/f2fs/<disk>/discard_idle_interval 206Date: September 2018 207Contact: "Chao Yu" <yuchao0@huawei.com> 208Contact: "Sahitya Tummala" <quic_stummala@quicinc.com> 209Description: Controls the idle timing of discard thread given 210 this time interval. 211 Default is 5 secs. 212 213What: /sys/fs/f2fs/<disk>/gc_idle_interval 214Date: September 2018 215Contact: "Chao Yu" <yuchao0@huawei.com> 216Contact: "Sahitya Tummala" <quic_stummala@quicinc.com> 217Description: Controls the idle timing for gc path. Set to 5 seconds by default. 218 219What: /sys/fs/f2fs/<disk>/iostat_enable 220Date: August 2017 221Contact: "Chao Yu" <yuchao0@huawei.com> 222Description: Controls to enable/disable IO stat. 223 224What: /sys/fs/f2fs/<disk>/ra_nid_pages 225Date: October 2015 226Contact: "Chao Yu" <chao2.yu@samsung.com> 227Description: Controls the count of nid pages to be readaheaded. 228 When building free nids, F2FS reads NAT blocks ahead for 229 speed up. Default is 0. 230 231What: /sys/fs/f2fs/<disk>/dirty_nats_ratio 232Date: January 2016 233Contact: "Chao Yu" <chao2.yu@samsung.com> 234Description: Controls dirty nat entries ratio threshold, if current 235 ratio exceeds configured threshold, checkpoint will 236 be triggered for flushing dirty nat entries. 237 238What: /sys/fs/f2fs/<disk>/lifetime_write_kbytes 239Date: January 2016 240Contact: "Shuoran Liu" <liushuoran@huawei.com> 241Description: Shows total written kbytes issued to disk. 242 243What: /sys/fs/f2fs/<disk>/features 244Date: July 2017 245Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 246Description: <deprecated: should use /sys/fs/f2fs/<disk>/feature_list/> 247 Shows all enabled features in current device. 248 Supported features: 249 encryption, blkzoned, extra_attr, projquota, inode_checksum, 250 flexible_inline_xattr, quota_ino, inode_crtime, lost_found, 251 verity, sb_checksum, casefold, readonly, compression, pin_file. 252 253What: /sys/fs/f2fs/<disk>/feature_list/ 254Date: June 2021 255Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 256Description: Expand /sys/fs/f2fs/<disk>/features to meet sysfs rule. 257 Supported on-disk features: 258 encryption, block_zoned (aka blkzoned), extra_attr, 259 project_quota (aka projquota), inode_checksum, 260 flexible_inline_xattr, quota_ino, inode_crtime, lost_found, 261 verity, sb_checksum, casefold, readonly, compression. 262 Note that, pin_file is moved into /sys/fs/f2fs/features/. 263 264What: /sys/fs/f2fs/features/ 265Date: July 2017 266Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 267Description: Shows all enabled kernel features. 268 Supported features: 269 encryption, block_zoned, extra_attr, project_quota, 270 inode_checksum, flexible_inline_xattr, quota_ino, 271 inode_crtime, lost_found, verity, sb_checksum, 272 casefold, readonly, compression, test_dummy_encryption_v2, 273 atomic_write, pin_file, encrypted_casefold, linear_lookup. 274 275What: /sys/fs/f2fs/<disk>/inject_rate 276Date: May 2016 277Contact: "Sheng Yong" <shengyong1@huawei.com> 278Description: Controls the injection rate of arbitrary faults. 279 280What: /sys/fs/f2fs/<disk>/inject_type 281Date: May 2016 282Contact: "Sheng Yong" <shengyong1@huawei.com> 283Description: Controls the injection type of arbitrary faults. 284 285What: /sys/fs/f2fs/<disk>/dirty_segments 286Date: October 2017 287Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 288Description: Shows the number of dirty segments. 289 290What: /sys/fs/f2fs/<disk>/reserved_blocks 291Date: June 2017 292Contact: "Chao Yu" <yuchao0@huawei.com> 293Description: Controls target reserved blocks in system, the threshold 294 is soft, it could exceed current available user space. 295 296What: /sys/fs/f2fs/<disk>/current_reserved_blocks 297Date: October 2017 298Contact: "Yunlong Song" <yunlong.song@huawei.com> 299Contact: "Chao Yu" <yuchao0@huawei.com> 300Description: Shows current reserved blocks in system, it may be temporarily 301 smaller than target_reserved_blocks, but will gradually 302 increase to target_reserved_blocks when more free blocks are 303 freed by user later. 304 305What: /sys/fs/f2fs/<disk>/gc_urgent 306Date: August 2017 307Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 308Description: Do background GC aggressively when set. Set to 0 by default. 309 gc urgent high(1): does GC forcibly in a period of given 310 gc_urgent_sleep_time and ignores I/O idling check. uses greedy 311 GC approach and turns SSR mode on. 312 gc urgent low(2): lowers the bar of checking I/O idling in 313 order to process outstanding discard commands and GC a 314 little bit aggressively. always uses cost benefit GC approach, 315 and will override age-threshold GC approach if ATGC is enabled 316 at the same time. 317 gc urgent mid(3): does GC forcibly in a period of given 318 gc_urgent_sleep_time and executes a mid level of I/O idling check. 319 always uses cost benefit GC approach, and will override 320 age-threshold GC approach if ATGC is enabled at the same time. 321 322What: /sys/fs/f2fs/<disk>/gc_urgent_sleep_time 323Date: August 2017 324Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 325Description: Controls sleep time of GC urgent mode. Set to 500ms by default. 326 327What: /sys/fs/f2fs/<disk>/readdir_ra 328Date: November 2017 329Contact: "Sheng Yong" <shengyong1@huawei.com> 330Description: Controls readahead inode block in readdir. Enabled by default. 331 332What: /sys/fs/f2fs/<disk>/gc_pin_file_thresh 333Date: January 2018 334Contact: Jaegeuk Kim <jaegeuk@kernel.org> 335Description: This indicates how many GC can be failed for the pinned 336 file. If it exceeds this, F2FS doesn't guarantee its pinning 337 state. 2048 trials is set by default, and 65535 as maximum. 338 339What: /sys/fs/f2fs/<disk>/extension_list 340Date: February 2018 341Contact: "Chao Yu" <yuchao0@huawei.com> 342Description: Used to control configure extension list: 343 - Query: cat /sys/fs/f2fs/<disk>/extension_list 344 - Add: echo '[h/c]extension' > /sys/fs/f2fs/<disk>/extension_list 345 - Del: echo '[h/c]!extension' > /sys/fs/f2fs/<disk>/extension_list 346 - [h] means add/del hot file extension 347 - [c] means add/del cold file extension 348 349What: /sys/fs/f2fs/<disk>/unusable 350Date: April 2019 351Contact: "Daniel Rosenberg" <drosen@google.com> 352Description: If checkpoint=disable, it displays the number of blocks that 353 are unusable. 354 If checkpoint=enable it displays the number of blocks that 355 would be unusable if checkpoint=disable were to be set. 356 357What: /sys/fs/f2fs/<disk>/encoding 358Date: July 2019 359Contact: "Daniel Rosenberg" <drosen@google.com> 360Description: Displays name and version of the encoding set for the filesystem. 361 If no encoding is set, displays (none) 362 363What: /sys/fs/f2fs/<disk>/free_segments 364Date: September 2019 365Contact: "Hridya Valsaraju" <hridya@google.com> 366Description: Number of free segments in disk. 367 368What: /sys/fs/f2fs/<disk>/cp_foreground_calls 369Date: September 2019 370Contact: "Hridya Valsaraju" <hridya@google.com> 371Description: Number of checkpoint operations performed on demand. Available when 372 CONFIG_F2FS_STAT_FS=y. 373 374What: /sys/fs/f2fs/<disk>/cp_background_calls 375Date: September 2019 376Contact: "Hridya Valsaraju" <hridya@google.com> 377Description: Number of checkpoint operations performed in the background to 378 free segments. Available when CONFIG_F2FS_STAT_FS=y. 379 380What: /sys/fs/f2fs/<disk>/gc_foreground_calls 381Date: September 2019 382Contact: "Hridya Valsaraju" <hridya@google.com> 383Description: Number of garbage collection operations performed on demand. 384 Available when CONFIG_F2FS_STAT_FS=y. 385 386What: /sys/fs/f2fs/<disk>/gc_background_calls 387Date: September 2019 388Contact: "Hridya Valsaraju" <hridya@google.com> 389Description: Number of garbage collection operations triggered in background. 390 Available when CONFIG_F2FS_STAT_FS=y. 391 392What: /sys/fs/f2fs/<disk>/moved_blocks_foreground 393Date: September 2019 394Contact: "Hridya Valsaraju" <hridya@google.com> 395Description: Number of blocks moved by garbage collection in foreground. 396 Available when CONFIG_F2FS_STAT_FS=y. 397 398What: /sys/fs/f2fs/<disk>/moved_blocks_background 399Date: September 2019 400Contact: "Hridya Valsaraju" <hridya@google.com> 401Description: Number of blocks moved by garbage collection in background. 402 Available when CONFIG_F2FS_STAT_FS=y. 403 404What: /sys/fs/f2fs/<disk>/avg_vblocks 405Date: September 2019 406Contact: "Hridya Valsaraju" <hridya@google.com> 407Description: Average number of valid blocks. 408 Available when CONFIG_F2FS_STAT_FS=y. 409 410What: /sys/fs/f2fs/<disk>/defrag_blocks 411Date: February 2026 412Contact: "Jinbao Liu" <liujinbao1@xiaomi.com> 413Description: Number of blocks moved by defragment. 414 Available when CONFIG_F2FS_STAT_FS=y. 415 416What: /sys/fs/f2fs/<disk>/mounted_time_sec 417Date: February 2020 418Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 419Description: Show the mounted time in secs of this partition. 420 421What: /sys/fs/f2fs/<disk>/data_io_flag 422Date: April 2020 423Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 424Description: Give a way to attach REQ_META|FUA to data writes 425 given temperature-based bits. Now the bits indicate: 426 427 +-------------------+-------------------+ 428 | REQ_META | REQ_FUA | 429 +------+------+-----+------+------+-----+ 430 | 5 | 4 | 3 | 2 | 1 | 0 | 431 +------+------+-----+------+------+-----+ 432 | Cold | Warm | Hot | Cold | Warm | Hot | 433 +------+------+-----+------+------+-----+ 434 435What: /sys/fs/f2fs/<disk>/node_io_flag 436Date: June 2020 437Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 438Description: Give a way to attach REQ_META|FUA to node writes 439 given temperature-based bits. Now the bits indicate: 440 441 +-------------------+-------------------+ 442 | REQ_META | REQ_FUA | 443 +------+------+-----+------+------+-----+ 444 | 5 | 4 | 3 | 2 | 1 | 0 | 445 +------+------+-----+------+------+-----+ 446 | Cold | Warm | Hot | Cold | Warm | Hot | 447 +------+------+-----+------+------+-----+ 448 449What: /sys/fs/f2fs/<disk>/iostat_period_ms 450Date: April 2020 451Contact: "Daeho Jeong" <daehojeong@google.com> 452Description: Give a way to change iostat_period time. 3secs by default. 453 The new iostat trace gives stats gap given the period. 454What: /sys/fs/f2fs/<disk>/max_io_bytes 455Date: December 2020 456Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 457Description: This gives a control to limit the bio size in f2fs. 458 Default is zero, which will follow underlying block layer limit, 459 whereas, if it has a certain bytes value, f2fs won't submit a 460 bio larger than that size. 461 462What: /sys/fs/f2fs/<disk>/stat/sb_status 463Date: December 2020 464Contact: "Chao Yu" <yuchao0@huawei.com> 465Description: Show status of f2fs superblock in real time. 466 467 ====== ===================== ================================= 468 value sb status macro description 469 0x1 SBI_IS_DIRTY dirty flag for checkpoint 470 0x2 SBI_IS_CLOSE specify unmounting 471 0x4 SBI_NEED_FSCK need fsck.f2fs to fix 472 0x8 SBI_POR_DOING recovery is doing or not 473 0x10 SBI_NEED_SB_WRITE need to recover superblock 474 0x20 SBI_NEED_CP need to checkpoint 475 0x40 SBI_IS_SHUTDOWN shutdown by ioctl 476 0x80 SBI_IS_RECOVERED recovered orphan/data 477 0x100 SBI_CP_DISABLED CP was disabled last mount 478 0x200 SBI_CP_DISABLED_QUICK CP was disabled quickly 479 0x400 SBI_QUOTA_NEED_FLUSH need to flush quota info in CP 480 0x800 SBI_QUOTA_SKIP_FLUSH skip flushing quota in current CP 481 0x1000 SBI_QUOTA_NEED_REPAIR quota file may be corrupted 482 0x2000 SBI_IS_RESIZEFS resizefs is in process 483 0x4000 SBI_IS_FREEZING freefs is in process 484 ====== ===================== ================================= 485 486What: /sys/fs/f2fs/<disk>/stat/cp_status 487Date: September 2022 488Contact: "Chao Yu" <chao.yu@oppo.com> 489Description: Show status of f2fs checkpoint in real time. 490 491 =============================== ============================== 492 cp flag value 493 CP_UMOUNT_FLAG 0x00000001 494 CP_ORPHAN_PRESENT_FLAG 0x00000002 495 CP_COMPACT_SUM_FLAG 0x00000004 496 CP_ERROR_FLAG 0x00000008 497 CP_FSCK_FLAG 0x00000010 498 CP_FASTBOOT_FLAG 0x00000020 499 CP_CRC_RECOVERY_FLAG 0x00000040 500 CP_NAT_BITS_FLAG 0x00000080 501 CP_TRIMMED_FLAG 0x00000100 502 CP_NOCRC_RECOVERY_FLAG 0x00000200 503 CP_LARGE_NAT_BITMAP_FLAG 0x00000400 504 CP_QUOTA_NEED_FSCK_FLAG 0x00000800 505 CP_DISABLED_FLAG 0x00001000 506 CP_DISABLED_QUICK_FLAG 0x00002000 507 CP_RESIZEFS_FLAG 0x00004000 508 =============================== ============================== 509 510What: /sys/fs/f2fs/<disk>/stat/issued_discard 511Date: December 2023 512Contact: "Zhiguo Niu" <zhiguo.niu@unisoc.com> 513Description: Shows the number of issued discard. 514 515What: /sys/fs/f2fs/<disk>/stat/queued_discard 516Date: December 2023 517Contact: "Zhiguo Niu" <zhiguo.niu@unisoc.com> 518Description: Shows the number of queued discard. 519 520What: /sys/fs/f2fs/<disk>/stat/undiscard_blks 521Date: December 2023 522Contact: "Zhiguo Niu" <zhiguo.niu@unisoc.com> 523Description: Shows the total number of undiscard blocks. 524 525What: /sys/fs/f2fs/<disk>/ckpt_thread_ioprio 526Date: January 2021 527Contact: "Daeho Jeong" <daehojeong@google.com> 528Description: Give a way to change checkpoint merge daemon's io priority. 529 Its default value is "rt,3", which means "RT" I/O class and 530 I/O priority "3". We can select the class between "rt" and "be", 531 and set the I/O priority within valid range of it. "," delimiter 532 is necessary in between I/O class and priority number. 533 534What: /sys/fs/f2fs/<disk>/ovp_segments 535Date: March 2021 536Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 537Description: Shows the number of overprovision segments. 538 539What: /sys/fs/f2fs/<disk>/compr_written_block 540Date: March 2021 541Contact: "Daeho Jeong" <daehojeong@google.com> 542Description: Show the block count written after compression since mount. Note 543 that when the compressed blocks are deleted, this count doesn't 544 decrease. If you write "0" here, you can initialize 545 compr_written_block and compr_saved_block to "0". 546 547What: /sys/fs/f2fs/<disk>/compr_saved_block 548Date: March 2021 549Contact: "Daeho Jeong" <daehojeong@google.com> 550Description: Show the saved block count with compression since mount. Note 551 that when the compressed blocks are deleted, this count doesn't 552 decrease. If you write "0" here, you can initialize 553 compr_written_block and compr_saved_block to "0". 554 555What: /sys/fs/f2fs/<disk>/compr_new_inode 556Date: March 2021 557Contact: "Daeho Jeong" <daehojeong@google.com> 558Description: Show the count of inode newly enabled for compression since mount. 559 Note that when the compression is disabled for the files, this count 560 doesn't decrease. If you write "0" here, you can initialize 561 compr_new_inode to "0". 562 563What: /sys/fs/f2fs/<disk>/atgc_candidate_ratio 564Date: May 2021 565Contact: "Chao Yu" <yuchao0@huawei.com> 566Description: When ATGC is on, it controls candidate ratio in order to limit total 567 number of potential victim in all candidates, the value should be in 568 range of [0, 100], by default it was initialized as 20(%). 569 570What: /sys/fs/f2fs/<disk>/atgc_candidate_count 571Date: May 2021 572Contact: "Chao Yu" <yuchao0@huawei.com> 573Description: When ATGC is on, it controls candidate count in order to limit total 574 number of potential victim in all candidates, by default it was 575 initialized as 10 (sections). 576 577What: /sys/fs/f2fs/<disk>/atgc_age_weight 578Date: May 2021 579Contact: "Chao Yu" <yuchao0@huawei.com> 580Description: When ATGC is on, it controls age weight to balance weight proportion 581 in between aging and valid blocks, the value should be in range of 582 [0, 100], by default it was initialized as 60(%). 583 584What: /sys/fs/f2fs/<disk>/atgc_age_threshold 585Date: May 2021 586Contact: "Chao Yu" <yuchao0@huawei.com> 587Description: When ATGC is on, it controls age threshold to bypass GCing young 588 candidates whose age is not beyond the threshold, by default it was 589 initialized as 604800 seconds (equals to 7 days). 590 591What: /sys/fs/f2fs/<disk>/atgc_enabled 592Date: Feb 2024 593Contact: "Jinbao Liu" <liujinbao1@xiaomi.com> 594Description: It represents whether ATGC is on or off. The value is 1 which 595 indicates that ATGC is on, and 0 indicates that it is off. 596 597What: /sys/fs/f2fs/<disk>/gc_reclaimed_segments 598Date: July 2021 599Contact: "Daeho Jeong" <daehojeong@google.com> 600Description: Show how many segments have been reclaimed by GC during a specific 601 GC mode (0: GC normal, 1: GC idle CB, 2: GC idle greedy, 602 3: GC idle AT, 4: GC urgent high, 5: GC urgent low 6: GC urgent mid) 603 You can re-initialize this value to "0". 604 605What: /sys/fs/f2fs/<disk>/gc_segment_mode 606Date: July 2021 607Contact: "Daeho Jeong" <daehojeong@google.com> 608Description: You can control for which gc mode the "gc_reclaimed_segments" node shows. 609 Refer to the description of the modes in "gc_reclaimed_segments". 610 611What: /sys/fs/f2fs/<disk>/seq_file_ra_mul 612Date: July 2021 613Contact: "Daeho Jeong" <daehojeong@google.com> 614Description: You can control the multiplier value of bdi device readahead window size 615 between 2 (default) and 256 for POSIX_FADV_SEQUENTIAL advise option. 616 617What: /sys/fs/f2fs/<disk>/max_fragment_chunk 618Date: August 2021 619Contact: "Daeho Jeong" <daehojeong@google.com> 620Description: With "mode=fragment:block" mount options, we can scatter block allocation. 621 f2fs will allocate 1..<max_fragment_chunk> blocks in a chunk and make a hole 622 in the length of 1..<max_fragment_hole> by turns. This value can be set 623 between 1..512 and the default value is 4. 624 625What: /sys/fs/f2fs/<disk>/max_fragment_hole 626Date: August 2021 627Contact: "Daeho Jeong" <daehojeong@google.com> 628Description: With "mode=fragment:block" mount options, we can scatter block allocation. 629 f2fs will allocate 1..<max_fragment_chunk> blocks in a chunk and make a hole 630 in the length of 1..<max_fragment_hole> by turns. This value can be set 631 between 1..512 and the default value is 4. 632 633What: /sys/fs/f2fs/<disk>/gc_remaining_trials 634Date: October 2022 635Contact: "Yangtao Li" <frank.li@vivo.com> 636Description: You can set the trial count limit for GC urgent and idle mode with this value. 637 If GC thread gets to the limit, the mode will turn back to GC normal mode. 638 By default, the value is zero, which means there is no limit like before. 639 640What: /sys/fs/f2fs/<disk>/max_roll_forward_node_blocks 641Date: January 2022 642Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 643Description: Controls max # of node block writes to be used for roll forward 644 recovery. This can limit the roll forward recovery time. 645 646What: /sys/fs/f2fs/<disk>/unusable_blocks_per_sec 647Date: June 2022 648Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 649Description: Shows the number of unusable blocks in a section which was defined by 650 the zone capacity reported by underlying zoned device. 651 652What: /sys/fs/f2fs/<disk>/max_open_zones 653Date: November 2025 654Contact: "Yongpeng Yang" <yangyongpeng@xiaomi.com> 655Description: Shows the max number of zones that F2FS can write concurrently when a zoned 656 device is mounted. 657 658What: /sys/fs/f2fs/<disk>/current_atomic_write 659Date: July 2022 660Contact: "Daeho Jeong" <daehojeong@google.com> 661Description: Show the total current atomic write block count, which is not committed yet. 662 This is a read-only entry. 663 664What: /sys/fs/f2fs/<disk>/peak_atomic_write 665Date: July 2022 666Contact: "Daeho Jeong" <daehojeong@google.com> 667Description: Show the peak value of total current atomic write block count after boot. 668 If you write "0" here, you can initialize to "0". 669 670What: /sys/fs/f2fs/<disk>/committed_atomic_block 671Date: July 2022 672Contact: "Daeho Jeong" <daehojeong@google.com> 673Description: Show the accumulated total committed atomic write block count after boot. 674 If you write "0" here, you can initialize to "0". 675 676What: /sys/fs/f2fs/<disk>/revoked_atomic_block 677Date: July 2022 678Contact: "Daeho Jeong" <daehojeong@google.com> 679Description: Show the accumulated total revoked atomic write block count after boot. 680 If you write "0" here, you can initialize to "0". 681 682What: /sys/fs/f2fs/<disk>/gc_mode 683Date: October 2022 684Contact: "Yangtao Li" <frank.li@vivo.com> 685Description: Show the current gc_mode as a string. 686 This is a read-only entry. 687 688What: /sys/fs/f2fs/<disk>/discard_urgent_util 689Date: November 2022 690Contact: "Yangtao Li" <frank.li@vivo.com> 691Description: When space utilization exceeds this, do background DISCARD aggressively. 692 Does DISCARD forcibly in a period of given min_discard_issue_time when the number 693 of discards is not 0 and set discard granularity to 1. 694 Default: 80 695 696What: /sys/fs/f2fs/<disk>/hot_data_age_threshold 697Date: November 2022 698Contact: "Ping Xiong" <xiongping1@xiaomi.com> 699Description: When DATA SEPARATION is on, it controls the age threshold to indicate 700 the data blocks as hot. By default it was initialized as 262144 blocks 701 (equals to 1GB). 702 703What: /sys/fs/f2fs/<disk>/warm_data_age_threshold 704Date: November 2022 705Contact: "Ping Xiong" <xiongping1@xiaomi.com> 706Description: When DATA SEPARATION is on, it controls the age threshold to indicate 707 the data blocks as warm. By default it was initialized as 2621440 blocks 708 (equals to 10GB). 709 710What: /sys/fs/f2fs/<disk>/fault_rate 711Date: May 2016 712Contact: "Sheng Yong" <shengyong@oppo.com> 713Contact: "Chao Yu" <chao@kernel.org> 714Description: Enable fault injection in all supported types with 715 specified injection rate. 716 717What: /sys/fs/f2fs/<disk>/fault_type 718Date: May 2016 719Contact: "Sheng Yong" <shengyong@oppo.com> 720Contact: "Chao Yu" <chao@kernel.org> 721Description: Support configuring fault injection type, should be 722 enabled with fault_injection option, fault type value 723 is shown below, it supports single or combined type. 724 725 =========================== ========== 726 Type_Name Type_Value 727 =========================== ========== 728 FAULT_KMALLOC 0x00000001 729 FAULT_KVMALLOC 0x00000002 730 FAULT_PAGE_ALLOC 0x00000004 731 FAULT_PAGE_GET 0x00000008 732 FAULT_ALLOC_BIO 0x00000010 (obsolete) 733 FAULT_ALLOC_NID 0x00000020 734 FAULT_ORPHAN 0x00000040 735 FAULT_BLOCK 0x00000080 736 FAULT_DIR_DEPTH 0x00000100 737 FAULT_EVICT_INODE 0x00000200 738 FAULT_TRUNCATE 0x00000400 739 FAULT_READ_IO 0x00000800 740 FAULT_CHECKPOINT 0x00001000 741 FAULT_DISCARD 0x00002000 (obsolete) 742 FAULT_WRITE_IO 0x00004000 743 FAULT_SLAB_ALLOC 0x00008000 744 FAULT_DQUOT_INIT 0x00010000 745 FAULT_LOCK_OP 0x00020000 746 FAULT_BLKADDR_VALIDITY 0x00040000 747 FAULT_BLKADDR_CONSISTENCE 0x00080000 748 FAULT_NO_SEGMENT 0x00100000 749 FAULT_INCONSISTENT_FOOTER 0x00200000 750 FAULT_ATOMIC_TIMEOUT 0x00400000 (1000ms) 751 FAULT_VMALLOC 0x00800000 752 FAULT_LOCK_TIMEOUT 0x01000000 (1000ms) 753 FAULT_SKIP_WRITE 0x02000000 754 =========================== ========== 755 756What: /sys/fs/f2fs/<disk>/discard_io_aware_gran 757Date: January 2023 758Contact: "Yangtao Li" <frank.li@vivo.com> 759Description: Controls background discard granularity of inner discard thread 760 when is not in idle. Inner thread will not issue discards with size that 761 is smaller than granularity. The unit size is one block(4KB), now only 762 support configuring in range of [0, 512]. 763 Default: 512 764 765What: /sys/fs/f2fs/<disk>/last_age_weight 766Date: January 2023 767Contact: "Ping Xiong" <xiongping1@xiaomi.com> 768Description: When DATA SEPARATION is on, it controls the weight of last data block age. 769 770What: /sys/fs/f2fs/<disk>/compress_watermark 771Date: February 2023 772Contact: "Yangtao Li" <frank.li@vivo.com> 773Description: When compress cache is on, it controls free memory watermark 774 in order to limit caching compress page. If free memory is lower 775 than watermark, then deny caching compress page. The value should be in 776 range of (0, 100], by default it was initialized as 20(%). 777 778What: /sys/fs/f2fs/<disk>/compress_percent 779Date: February 2023 780Contact: "Yangtao Li" <frank.li@vivo.com> 781Description: When compress cache is on, it controls cached page 782 percent(compress pages / free_ram) in order to limit caching compress page. 783 If cached page percent exceed threshold, then deny caching compress page. 784 The value should be in range of (0, 100], by default it was initialized 785 as 20(%). 786 787What: /sys/fs/f2fs/<disk>/discard_io_aware 788Date: November 2023 789Contact: "Chao Yu" <chao@kernel.org> 790Description: It controls to enable/disable IO aware feature for background discard. 791 By default, the value is 1 which indicates IO aware is on. 792 793What: /sys/fs/f2fs/<disk>/blkzone_alloc_policy 794Date: July 2024 795Contact: "Yuanhong Liao" <liaoyuanhong@vivo.com> 796Description: The zone UFS we are currently using consists of two parts: 797 conventional zones and sequential zones. It can be used to control which part 798 to prioritize for writes, with a default value of 0. 799 800 ======================== ========================================= 801 value description 802 blkzone_alloc_policy = 0 Prioritize writing to sequential zones 803 blkzone_alloc_policy = 1 Only allow writing to sequential zones 804 blkzone_alloc_policy = 2 Prioritize writing to conventional zones 805 ======================== ========================================= 806 807What: /sys/fs/f2fs/<disk>/migration_window_granularity 808Date: September 2024 809Contact: "Daeho Jeong" <daehojeong@google.com> 810Description: Controls migration window granularity of garbage collection on large 811 section. it can control the scanning window granularity for GC migration 812 in a unit of segment, while migration_granularity controls the number 813 of segments which can be migrated at the same turn. 814 815What: /sys/fs/f2fs/<disk>/reserved_segments 816Date: September 2024 817Contact: "Daeho Jeong" <daehojeong@google.com> 818Description: In order to fine tune GC behavior, we can control the number of 819 reserved segments. 820 821What: /sys/fs/f2fs/<disk>/gc_no_zoned_gc_percent 822Date: September 2024 823Contact: "Daeho Jeong" <daehojeong@google.com> 824Description: If the percentage of free sections over total sections is above this 825 number, F2FS do not garbage collection for zoned devices through the 826 background GC thread. the default number is "60". 827 828What: /sys/fs/f2fs/<disk>/gc_boost_zoned_gc_percent 829Date: September 2024 830Contact: "Daeho Jeong" <daehojeong@google.com> 831Description: If the percentage of free sections over total sections is under this 832 number, F2FS boosts garbage collection for zoned devices through the 833 background GC thread. the default number is "25". 834 835What: /sys/fs/f2fs/<disk>/gc_valid_thresh_ratio 836Date: September 2024 837Contact: "Daeho Jeong" <daehojeong@google.com> 838Description: It controls the valid block ratio threshold not to trigger excessive GC 839 for zoned devices. The initial value of it is 95(%). F2FS will stop the 840 background GC thread from initiating GC for sections having valid blocks 841 exceeding the ratio. 842 843What: /sys/fs/f2fs/<disk>/max_read_extent_count 844Date: November 2024 845Contact: "Chao Yu" <chao@kernel.org> 846Description: It controls max read extent count for per-inode, the value of threshold 847 is 10240 by default. 848 849What: /sys/fs/f2fs/tuning/reclaim_caches_kb 850Date: February 2025 851Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 852Description: It reclaims the given KBs of file-backed pages registered by 853 ioctl(F2FS_IOC_DONATE_RANGE). 854 For example, writing N tries to drop N KBs spaces in LRU. 855 856What: /sys/fs/f2fs/<disk>/carve_out 857Date: March 2025 858Contact: "Daeho Jeong" <daehojeong@google.com> 859Description: For several zoned storage devices, vendors will provide extra space which 860 was used for device level GC than specs and F2FS can use this space for 861 filesystem level GC. To do that, we can reserve the space using 862 reserved_blocks. However, it is not enough, since this extra space should 863 not be shown to users. So, with this new sysfs node, we can hide the space 864 by subtracting reserved_blocks from total bytes. 865 866What: /sys/fs/f2fs/<disk>/encoding_flags 867Date: April 2025 868Contact: "Chao Yu" <chao@kernel.org> 869Description: This is a read-only entry to show the value of sb.s_encoding_flags, the 870 value is hexadecimal. 871 872 ============================ ========== 873 Flag_Name Flag_Value 874 ============================ ========== 875 SB_ENC_STRICT_MODE_FL 0x00000001 876 SB_ENC_NO_COMPAT_FALLBACK_FL 0x00000002 877 ============================ ========== 878 879What: /sys/fs/f2fs/<disk>/reserved_pin_section 880Date: June 2025 881Contact: "Chao Yu" <chao@kernel.org> 882Description: This threshold is used to control triggering garbage collection while 883 fallocating on pinned file, so, it can guarantee there is enough free 884 reserved section before preallocating on pinned file. 885 By default, the value is ovp_sections, especially, for zoned ufs, the 886 value is 1. 887 888What: /sys/fs/f2fs/<disk>/gc_boost_gc_multiple 889Date: June 2025 890Contact: "Daeho Jeong" <daehojeong@google.com> 891Description: Set a multiplier for the background GC migration window when F2FS GC is 892 boosted. The range should be from 1 to the segment count in a section. 893 Default: 5 894 895What: /sys/fs/f2fs/<disk>/gc_boost_gc_greedy 896Date: June 2025 897Contact: "Daeho Jeong" <daehojeong@google.com> 898Description: Control GC algorithm for boost GC. 0: cost benefit, 1: greedy 899 Default: 1 900 901What: /sys/fs/f2fs/<disk>/effective_lookup_mode 902Date: August 2025 903Contact: "Daniel Lee" <chullee@google.com> 904Description: 905 This is a read-only entry to show the effective directory lookup mode 906 F2FS is currently using for casefolded directories. 907 This considers both the "lookup_mode" mount option and the on-disk 908 encoding flag, SB_ENC_NO_COMPAT_FALLBACK_FL. 909 910 Possible values are: 911 - "perf": Hash-only lookup. 912 - "compat": Hash-based lookup with a linear search fallback enabled 913 - "auto:perf": lookup_mode is auto and fallback is disabled on-disk 914 - "auto:compat": lookup_mode is auto and fallback is enabled on-disk 915 916What: /sys/fs/f2fs/<disk>/bggc_io_aware 917Date: August 2025 918Contact: "Liao Yuanhong" <liaoyuanhong@vivo.com> 919Description: Used to adjust the BG_GC priority when pending IO, with a default value 920 of 0. Specifically, for ZUFS, the default value is 1. 921 922 ================== ====================================================== 923 value description 924 bggc_io_aware = 0 skip background GC if there is any kind of pending IO 925 bggc_io_aware = 1 skip background GC if there is pending read IO 926 bggc_io_aware = 2 don't aware IO for background GC 927 ================== ====================================================== 928 929What: /sys/fs/f2fs/<disk>/allocate_section_hint 930Date: August 2025 931Contact: "Liao Yuanhong" <liaoyuanhong@vivo.com> 932Description: Indicates the hint section between the first device and others in multi-devices 933 setup. It defaults to the end of the first device in sections. For a single storage 934 device, it defaults to the total number of sections. It can be manually set to match 935 scenarios where multi-devices are mapped to the same dm device. 936 937What: /sys/fs/f2fs/<disk>/allocate_section_policy 938Date: August 2025 939Contact: "Liao Yuanhong" <liaoyuanhong@vivo.com> 940Description: Controls write priority in multi-devices setups. A value of 0 means normal writing. 941 A value of 1 prioritizes writing to devices before the allocate_section_hint. A value of 2 942 prioritizes writing to devices after the allocate_section_hint. The default is 0. 943 944 =========================== ========================================================== 945 value description 946 allocate_section_policy = 0 Normal writing 947 allocate_section_policy = 1 Prioritize writing to section before allocate_section_hint 948 allocate_section_policy = 2 Prioritize writing to section after allocate_section_hint 949 =========================== ========================================================== 950 951What: /sys/fs/f2fs/<disk>/max_lock_elapsed_time 952Date: December 2025 953Contact: "Chao Yu" <chao@kernel.org> 954Description: This is a threshold, once a thread enters critical region that lock covers, total 955 elapsed time exceeds this threshold, f2fs will print tracepoint to dump information 956 of related context. This sysfs entry can be used to control the value of threshold, 957 by default, the value is 500 ms. 958 959What: /sys/fs/f2fs/<disk>/inject_timeout_type 960Date: December 2025 961Contact: "Chao Yu" <chao@kernel.org> 962Description: This sysfs entry can be used to change type of injected timeout: 963 ========== =============================== 964 Flag_Value Flag_Description 965 ========== =============================== 966 0x00000000 No timeout (default) 967 0x00000001 Simulate running time 968 0x00000002 Simulate IO type sleep time 969 0x00000003 Simulate Non-IO type sleep time 970 0x00000004 Simulate runnable time 971 ========== =============================== 972 973What: /sys/fs/f2fs/<disk>/adjust_lock_priority 974Date: January 2026 975Contact: "Chao Yu" <chao@kernel.org> 976Description: This sysfs entry can be used to enable/disable to adjust priority for task 977 which is in critical region covered by lock. 978 ========== ================== 979 Flag_Value Flag_Description 980 ========== ================== 981 0x00000000 Disabled (default) 982 0x00000001 cp_rwsem 983 0x00000002 node_change 984 0x00000004 node_write 985 0x00000008 gc_lock 986 0x00000010 cp_global 987 0x00000020 io_rwsem 988 ========== ================== 989 990What: /sys/fs/f2fs/<disk>/lock_duration_priority 991Date: January 2026 992Contact: "Chao Yu" <chao@kernel.org> 993Description: f2fs can tune priority of thread which has entered into critical region covered by 994 f2fs rwsemphore lock. This sysfs entry can be used to control priority value, the 995 range is [100,139], by default the value is 120. 996 997What: /sys/fs/f2fs/<disk>/critical_task_priority 998Date: February 2026 999Contact: "Chao Yu" <chao@kernel.org> 1000Description: It can be used to tune priority of f2fs critical task, e.g. f2fs_ckpt, f2fs_gc 1001 threads, limitation as below: 1002 - it requires user has CAP_SYS_NICE capability. 1003 - the range is [100, 139], by default the value is 100. 1004