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 fserror. 275 276What: /sys/fs/f2fs/<disk>/inject_rate 277Date: May 2016 278Contact: "Sheng Yong" <shengyong1@huawei.com> 279Description: Controls the injection rate of arbitrary faults. 280 281What: /sys/fs/f2fs/<disk>/inject_type 282Date: May 2016 283Contact: "Sheng Yong" <shengyong1@huawei.com> 284Description: Controls the injection type of arbitrary faults. 285 286What: /sys/fs/f2fs/<disk>/dirty_segments 287Date: October 2017 288Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 289Description: Shows the number of dirty segments. 290 291What: /sys/fs/f2fs/<disk>/reserved_blocks 292Date: June 2017 293Contact: "Chao Yu" <yuchao0@huawei.com> 294Description: Controls target reserved blocks in system, the threshold 295 is soft, it could exceed current available user space. 296 297What: /sys/fs/f2fs/<disk>/current_reserved_blocks 298Date: October 2017 299Contact: "Yunlong Song" <yunlong.song@huawei.com> 300Contact: "Chao Yu" <yuchao0@huawei.com> 301Description: Shows current reserved blocks in system, it may be temporarily 302 smaller than target_reserved_blocks, but will gradually 303 increase to target_reserved_blocks when more free blocks are 304 freed by user later. 305 306What: /sys/fs/f2fs/<disk>/gc_urgent 307Date: August 2017 308Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 309Description: Do background GC aggressively when set. Set to 0 by default. 310 gc urgent high(1): does GC forcibly in a period of given 311 gc_urgent_sleep_time and ignores I/O idling check. uses greedy 312 GC approach and turns SSR mode on. 313 gc urgent low(2): lowers the bar of checking I/O idling in 314 order to process outstanding discard commands and GC a 315 little bit aggressively. always uses cost benefit GC approach, 316 and will override age-threshold GC approach if ATGC is enabled 317 at the same time. 318 gc urgent mid(3): does GC forcibly in a period of given 319 gc_urgent_sleep_time and executes a mid level of I/O idling check. 320 always uses cost benefit GC approach, and will override 321 age-threshold GC approach if ATGC is enabled at the same time. 322 323What: /sys/fs/f2fs/<disk>/gc_urgent_sleep_time 324Date: August 2017 325Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 326Description: Controls sleep time of GC urgent mode. Set to 500ms by default. 327 328What: /sys/fs/f2fs/<disk>/readdir_ra 329Date: November 2017 330Contact: "Sheng Yong" <shengyong1@huawei.com> 331Description: Controls readahead inode block in readdir. Enabled by default. 332 333What: /sys/fs/f2fs/<disk>/gc_pin_file_thresh 334Date: January 2018 335Contact: Jaegeuk Kim <jaegeuk@kernel.org> 336Description: This indicates how many GC can be failed for the pinned 337 file. If it exceeds this, F2FS doesn't guarantee its pinning 338 state. 2048 trials is set by default, and 65535 as maximum. 339 340What: /sys/fs/f2fs/<disk>/extension_list 341Date: February 2018 342Contact: "Chao Yu" <yuchao0@huawei.com> 343Description: Used to control configure extension list: 344 - Query: cat /sys/fs/f2fs/<disk>/extension_list 345 - Add: echo '[h/c]extension' > /sys/fs/f2fs/<disk>/extension_list 346 - Del: echo '[h/c]!extension' > /sys/fs/f2fs/<disk>/extension_list 347 - [h] means add/del hot file extension 348 - [c] means add/del cold file extension 349 350What: /sys/fs/f2fs/<disk>/unusable 351Date: April 2019 352Contact: "Daniel Rosenberg" <drosen@google.com> 353Description: If checkpoint=disable, it displays the number of blocks that 354 are unusable. 355 If checkpoint=enable it displays the number of blocks that 356 would be unusable if checkpoint=disable were to be set. 357 358What: /sys/fs/f2fs/<disk>/encoding 359Date: July 2019 360Contact: "Daniel Rosenberg" <drosen@google.com> 361Description: Displays name and version of the encoding set for the filesystem. 362 If no encoding is set, displays (none) 363 364What: /sys/fs/f2fs/<disk>/free_segments 365Date: September 2019 366Contact: "Hridya Valsaraju" <hridya@google.com> 367Description: Number of free segments in disk. 368 369What: /sys/fs/f2fs/<disk>/cp_foreground_calls 370Date: September 2019 371Contact: "Hridya Valsaraju" <hridya@google.com> 372Description: Number of checkpoint operations performed on demand. Available when 373 CONFIG_F2FS_STAT_FS=y. 374 375What: /sys/fs/f2fs/<disk>/cp_background_calls 376Date: September 2019 377Contact: "Hridya Valsaraju" <hridya@google.com> 378Description: Number of checkpoint operations performed in the background to 379 free segments. Available when CONFIG_F2FS_STAT_FS=y. 380 381What: /sys/fs/f2fs/<disk>/gc_foreground_calls 382Date: September 2019 383Contact: "Hridya Valsaraju" <hridya@google.com> 384Description: Number of garbage collection operations performed on demand. 385 Available when CONFIG_F2FS_STAT_FS=y. 386 387What: /sys/fs/f2fs/<disk>/gc_background_calls 388Date: September 2019 389Contact: "Hridya Valsaraju" <hridya@google.com> 390Description: Number of garbage collection operations triggered in background. 391 Available when CONFIG_F2FS_STAT_FS=y. 392 393What: /sys/fs/f2fs/<disk>/moved_blocks_foreground 394Date: September 2019 395Contact: "Hridya Valsaraju" <hridya@google.com> 396Description: Number of blocks moved by garbage collection in foreground. 397 Available when CONFIG_F2FS_STAT_FS=y. 398 399What: /sys/fs/f2fs/<disk>/moved_blocks_background 400Date: September 2019 401Contact: "Hridya Valsaraju" <hridya@google.com> 402Description: Number of blocks moved by garbage collection in background. 403 Available when CONFIG_F2FS_STAT_FS=y. 404 405What: /sys/fs/f2fs/<disk>/avg_vblocks 406Date: September 2019 407Contact: "Hridya Valsaraju" <hridya@google.com> 408Description: Average number of valid blocks. 409 Available when CONFIG_F2FS_STAT_FS=y. 410 411What: /sys/fs/f2fs/<disk>/defrag_blocks 412Date: February 2026 413Contact: "Jinbao Liu" <liujinbao1@xiaomi.com> 414Description: Number of blocks moved by defragment. 415 Available when CONFIG_F2FS_STAT_FS=y. 416 417What: /sys/fs/f2fs/<disk>/mounted_time_sec 418Date: February 2020 419Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 420Description: Show the mounted time in secs of this partition. 421 422What: /sys/fs/f2fs/<disk>/data_io_flag 423Date: April 2020 424Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 425Description: Give a way to attach REQ_META|FUA to data writes 426 given temperature-based bits. Now the bits indicate: 427 428 +-------------------+-------------------+ 429 | REQ_META | REQ_FUA | 430 +------+------+-----+------+------+-----+ 431 | 5 | 4 | 3 | 2 | 1 | 0 | 432 +------+------+-----+------+------+-----+ 433 | Cold | Warm | Hot | Cold | Warm | Hot | 434 +------+------+-----+------+------+-----+ 435 436What: /sys/fs/f2fs/<disk>/node_io_flag 437Date: June 2020 438Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 439Description: Give a way to attach REQ_META|FUA to node writes 440 given temperature-based bits. Now the bits indicate: 441 442 +-------------------+-------------------+ 443 | REQ_META | REQ_FUA | 444 +------+------+-----+------+------+-----+ 445 | 5 | 4 | 3 | 2 | 1 | 0 | 446 +------+------+-----+------+------+-----+ 447 | Cold | Warm | Hot | Cold | Warm | Hot | 448 +------+------+-----+------+------+-----+ 449 450What: /sys/fs/f2fs/<disk>/iostat_period_ms 451Date: April 2020 452Contact: "Daeho Jeong" <daehojeong@google.com> 453Description: Give a way to change iostat_period time. 3secs by default. 454 The new iostat trace gives stats gap given the period. 455What: /sys/fs/f2fs/<disk>/max_io_bytes 456Date: December 2020 457Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 458Description: This gives a control to limit the bio size in f2fs. 459 Default is zero, which will follow underlying block layer limit, 460 whereas, if it has a certain bytes value, f2fs won't submit a 461 bio larger than that size. 462 463What: /sys/fs/f2fs/<disk>/stat/sb_status 464Date: December 2020 465Contact: "Chao Yu" <yuchao0@huawei.com> 466Description: Show status of f2fs superblock in real time. 467 468 ====== ===================== ================================= 469 value sb status macro description 470 0x1 SBI_IS_DIRTY dirty flag for checkpoint 471 0x2 SBI_IS_CLOSE specify unmounting 472 0x4 SBI_NEED_FSCK need fsck.f2fs to fix 473 0x8 SBI_POR_DOING recovery is doing or not 474 0x10 SBI_NEED_SB_WRITE need to recover superblock 475 0x20 SBI_NEED_CP need to checkpoint 476 0x40 SBI_IS_SHUTDOWN shutdown by ioctl 477 0x80 SBI_IS_RECOVERED recovered orphan/data 478 0x100 SBI_CP_DISABLED CP was disabled last mount 479 0x200 SBI_CP_DISABLED_QUICK CP was disabled quickly 480 0x400 SBI_QUOTA_NEED_FLUSH need to flush quota info in CP 481 0x800 SBI_QUOTA_SKIP_FLUSH skip flushing quota in current CP 482 0x1000 SBI_QUOTA_NEED_REPAIR quota file may be corrupted 483 0x2000 SBI_IS_RESIZEFS resizefs is in process 484 0x4000 SBI_IS_FREEZING freefs is in process 485 ====== ===================== ================================= 486 487What: /sys/fs/f2fs/<disk>/stat/cp_status 488Date: September 2022 489Contact: "Chao Yu" <chao.yu@oppo.com> 490Description: Show status of f2fs checkpoint in real time. 491 492 =============================== ============================== 493 cp flag value 494 CP_UMOUNT_FLAG 0x00000001 495 CP_ORPHAN_PRESENT_FLAG 0x00000002 496 CP_COMPACT_SUM_FLAG 0x00000004 497 CP_ERROR_FLAG 0x00000008 498 CP_FSCK_FLAG 0x00000010 499 CP_FASTBOOT_FLAG 0x00000020 500 CP_CRC_RECOVERY_FLAG 0x00000040 501 CP_NAT_BITS_FLAG 0x00000080 502 CP_TRIMMED_FLAG 0x00000100 503 CP_NOCRC_RECOVERY_FLAG 0x00000200 504 CP_LARGE_NAT_BITMAP_FLAG 0x00000400 505 CP_QUOTA_NEED_FSCK_FLAG 0x00000800 506 CP_DISABLED_FLAG 0x00001000 507 CP_DISABLED_QUICK_FLAG 0x00002000 508 CP_RESIZEFS_FLAG 0x00004000 509 =============================== ============================== 510 511What: /sys/fs/f2fs/<disk>/stat/issued_discard 512Date: December 2023 513Contact: "Zhiguo Niu" <zhiguo.niu@unisoc.com> 514Description: Shows the number of issued discard. 515 516What: /sys/fs/f2fs/<disk>/stat/queued_discard 517Date: December 2023 518Contact: "Zhiguo Niu" <zhiguo.niu@unisoc.com> 519Description: Shows the number of queued discard. 520 521What: /sys/fs/f2fs/<disk>/stat/undiscard_blks 522Date: December 2023 523Contact: "Zhiguo Niu" <zhiguo.niu@unisoc.com> 524Description: Shows the total number of undiscard blocks. 525 526What: /sys/fs/f2fs/<disk>/ckpt_thread_ioprio 527Date: January 2021 528Contact: "Daeho Jeong" <daehojeong@google.com> 529Description: Give a way to change checkpoint merge daemon's io priority. 530 Its default value is "rt,3", which means "RT" I/O class and 531 I/O priority "3". We can select the class between "rt" and "be", 532 and set the I/O priority within valid range of it. "," delimiter 533 is necessary in between I/O class and priority number. 534 535What: /sys/fs/f2fs/<disk>/ovp_segments 536Date: March 2021 537Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 538Description: Shows the number of overprovision segments. 539 540What: /sys/fs/f2fs/<disk>/compr_written_block 541Date: March 2021 542Contact: "Daeho Jeong" <daehojeong@google.com> 543Description: Show the block count written after compression since mount. Note 544 that when the compressed blocks are deleted, this count doesn't 545 decrease. If you write "0" here, you can initialize 546 compr_written_block and compr_saved_block to "0". 547 548What: /sys/fs/f2fs/<disk>/compr_saved_block 549Date: March 2021 550Contact: "Daeho Jeong" <daehojeong@google.com> 551Description: Show the saved block count with compression since mount. Note 552 that when the compressed blocks are deleted, this count doesn't 553 decrease. If you write "0" here, you can initialize 554 compr_written_block and compr_saved_block to "0". 555 556What: /sys/fs/f2fs/<disk>/compr_new_inode 557Date: March 2021 558Contact: "Daeho Jeong" <daehojeong@google.com> 559Description: Show the count of inode newly enabled for compression since mount. 560 Note that when the compression is disabled for the files, this count 561 doesn't decrease. If you write "0" here, you can initialize 562 compr_new_inode to "0". 563 564What: /sys/fs/f2fs/<disk>/atgc_candidate_ratio 565Date: May 2021 566Contact: "Chao Yu" <yuchao0@huawei.com> 567Description: When ATGC is on, it controls candidate ratio in order to limit total 568 number of potential victim in all candidates, the value should be in 569 range of [0, 100], by default it was initialized as 20(%). 570 571What: /sys/fs/f2fs/<disk>/atgc_candidate_count 572Date: May 2021 573Contact: "Chao Yu" <yuchao0@huawei.com> 574Description: When ATGC is on, it controls candidate count in order to limit total 575 number of potential victim in all candidates, by default it was 576 initialized as 10 (sections). 577 578What: /sys/fs/f2fs/<disk>/atgc_age_weight 579Date: May 2021 580Contact: "Chao Yu" <yuchao0@huawei.com> 581Description: When ATGC is on, it controls age weight to balance weight proportion 582 in between aging and valid blocks, the value should be in range of 583 [0, 100], by default it was initialized as 60(%). 584 585What: /sys/fs/f2fs/<disk>/atgc_age_threshold 586Date: May 2021 587Contact: "Chao Yu" <yuchao0@huawei.com> 588Description: When ATGC is on, it controls age threshold to bypass GCing young 589 candidates whose age is not beyond the threshold, by default it was 590 initialized as 604800 seconds (equals to 7 days). 591 592What: /sys/fs/f2fs/<disk>/atgc_enabled 593Date: Feb 2024 594Contact: "Jinbao Liu" <liujinbao1@xiaomi.com> 595Description: It represents whether ATGC is on or off. The value is 1 which 596 indicates that ATGC is on, and 0 indicates that it is off. 597 598What: /sys/fs/f2fs/<disk>/gc_reclaimed_segments 599Date: July 2021 600Contact: "Daeho Jeong" <daehojeong@google.com> 601Description: Show how many segments have been reclaimed by GC during a specific 602 GC mode (0: GC normal, 1: GC idle CB, 2: GC idle greedy, 603 3: GC idle AT, 4: GC urgent high, 5: GC urgent low 6: GC urgent mid) 604 You can re-initialize this value to "0". 605 606What: /sys/fs/f2fs/<disk>/gc_segment_mode 607Date: July 2021 608Contact: "Daeho Jeong" <daehojeong@google.com> 609Description: You can control for which gc mode the "gc_reclaimed_segments" node shows. 610 Refer to the description of the modes in "gc_reclaimed_segments". 611 612What: /sys/fs/f2fs/<disk>/seq_file_ra_mul 613Date: July 2021 614Contact: "Daeho Jeong" <daehojeong@google.com> 615Description: You can control the multiplier value of bdi device readahead window size 616 between 2 (default) and 256 for POSIX_FADV_SEQUENTIAL advise option. 617 618What: /sys/fs/f2fs/<disk>/max_fragment_chunk 619Date: August 2021 620Contact: "Daeho Jeong" <daehojeong@google.com> 621Description: With "mode=fragment:block" mount options, we can scatter block allocation. 622 f2fs will allocate 1..<max_fragment_chunk> blocks in a chunk and make a hole 623 in the length of 1..<max_fragment_hole> by turns. This value can be set 624 between 1..512 and the default value is 4. 625 626What: /sys/fs/f2fs/<disk>/max_fragment_hole 627Date: August 2021 628Contact: "Daeho Jeong" <daehojeong@google.com> 629Description: With "mode=fragment:block" mount options, we can scatter block allocation. 630 f2fs will allocate 1..<max_fragment_chunk> blocks in a chunk and make a hole 631 in the length of 1..<max_fragment_hole> by turns. This value can be set 632 between 1..512 and the default value is 4. 633 634What: /sys/fs/f2fs/<disk>/gc_remaining_trials 635Date: October 2022 636Contact: "Yangtao Li" <frank.li@vivo.com> 637Description: You can set the trial count limit for GC urgent and idle mode with this value. 638 If GC thread gets to the limit, the mode will turn back to GC normal mode. 639 By default, the value is zero, which means there is no limit like before. 640 641What: /sys/fs/f2fs/<disk>/max_roll_forward_node_blocks 642Date: January 2022 643Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 644Description: Controls max # of node block writes to be used for roll forward 645 recovery. This can limit the roll forward recovery time. 646 647What: /sys/fs/f2fs/<disk>/unusable_blocks_per_sec 648Date: June 2022 649Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 650Description: Shows the number of unusable blocks in a section which was defined by 651 the zone capacity reported by underlying zoned device. 652 653What: /sys/fs/f2fs/<disk>/max_open_zones 654Date: November 2025 655Contact: "Yongpeng Yang" <yangyongpeng@xiaomi.com> 656Description: Shows the max number of zones that F2FS can write concurrently when a zoned 657 device is mounted. 658 659What: /sys/fs/f2fs/<disk>/current_atomic_write 660Date: July 2022 661Contact: "Daeho Jeong" <daehojeong@google.com> 662Description: Show the total current atomic write block count, which is not committed yet. 663 This is a read-only entry. 664 665What: /sys/fs/f2fs/<disk>/peak_atomic_write 666Date: July 2022 667Contact: "Daeho Jeong" <daehojeong@google.com> 668Description: Show the peak value of total current atomic write block count after boot. 669 If you write "0" here, you can initialize to "0". 670 671What: /sys/fs/f2fs/<disk>/committed_atomic_block 672Date: July 2022 673Contact: "Daeho Jeong" <daehojeong@google.com> 674Description: Show the accumulated total committed atomic write block count after boot. 675 If you write "0" here, you can initialize to "0". 676 677What: /sys/fs/f2fs/<disk>/revoked_atomic_block 678Date: July 2022 679Contact: "Daeho Jeong" <daehojeong@google.com> 680Description: Show the accumulated total revoked atomic write block count after boot. 681 If you write "0" here, you can initialize to "0". 682 683What: /sys/fs/f2fs/<disk>/gc_mode 684Date: October 2022 685Contact: "Yangtao Li" <frank.li@vivo.com> 686Description: Show the current gc_mode as a string. 687 This is a read-only entry. 688 689What: /sys/fs/f2fs/<disk>/discard_urgent_util 690Date: November 2022 691Contact: "Yangtao Li" <frank.li@vivo.com> 692Description: When space utilization exceeds this, do background DISCARD aggressively. 693 Does DISCARD forcibly in a period of given min_discard_issue_time when the number 694 of discards is not 0 and set discard granularity to 1. 695 Default: 80 696 697What: /sys/fs/f2fs/<disk>/hot_data_age_threshold 698Date: November 2022 699Contact: "Ping Xiong" <xiongping1@xiaomi.com> 700Description: When DATA SEPARATION is on, it controls the age threshold to indicate 701 the data blocks as hot. By default it was initialized as 262144 blocks 702 (equals to 1GB). 703 704What: /sys/fs/f2fs/<disk>/warm_data_age_threshold 705Date: November 2022 706Contact: "Ping Xiong" <xiongping1@xiaomi.com> 707Description: When DATA SEPARATION is on, it controls the age threshold to indicate 708 the data blocks as warm. By default it was initialized as 2621440 blocks 709 (equals to 10GB). 710 711What: /sys/fs/f2fs/<disk>/fault_rate 712Date: May 2016 713Contact: "Sheng Yong" <shengyong@oppo.com> 714Contact: "Chao Yu" <chao@kernel.org> 715Description: Enable fault injection in all supported types with 716 specified injection rate. 717 718What: /sys/fs/f2fs/<disk>/fault_type 719Date: May 2016 720Contact: "Sheng Yong" <shengyong@oppo.com> 721Contact: "Chao Yu" <chao@kernel.org> 722Description: Support configuring fault injection type, should be 723 enabled with fault_injection option, fault type value 724 is shown below, it supports single or combined type. 725 726 =========================== ========== 727 Type_Name Type_Value 728 =========================== ========== 729 FAULT_KMALLOC 0x00000001 730 FAULT_KVMALLOC 0x00000002 731 FAULT_PAGE_ALLOC 0x00000004 732 FAULT_PAGE_GET 0x00000008 733 FAULT_ALLOC_BIO 0x00000010 (obsolete) 734 FAULT_ALLOC_NID 0x00000020 735 FAULT_ORPHAN 0x00000040 736 FAULT_BLOCK 0x00000080 737 FAULT_DIR_DEPTH 0x00000100 738 FAULT_EVICT_INODE 0x00000200 739 FAULT_TRUNCATE 0x00000400 740 FAULT_READ_IO 0x00000800 741 FAULT_CHECKPOINT 0x00001000 742 FAULT_DISCARD 0x00002000 (obsolete) 743 FAULT_WRITE_IO 0x00004000 744 FAULT_SLAB_ALLOC 0x00008000 745 FAULT_DQUOT_INIT 0x00010000 746 FAULT_LOCK_OP 0x00020000 747 FAULT_BLKADDR_VALIDITY 0x00040000 748 FAULT_BLKADDR_CONSISTENCE 0x00080000 749 FAULT_NO_SEGMENT 0x00100000 750 FAULT_INCONSISTENT_FOOTER 0x00200000 751 FAULT_ATOMIC_TIMEOUT 0x00400000 (1000ms) 752 FAULT_VMALLOC 0x00800000 753 FAULT_LOCK_TIMEOUT 0x01000000 (1000ms) 754 FAULT_SKIP_WRITE 0x02000000 755 =========================== ========== 756 757What: /sys/fs/f2fs/<disk>/discard_io_aware_gran 758Date: January 2023 759Contact: "Yangtao Li" <frank.li@vivo.com> 760Description: Controls background discard granularity of inner discard thread 761 when is not in idle. Inner thread will not issue discards with size that 762 is smaller than granularity. The unit size is one block(4KB), now only 763 support configuring in range of [0, 512]. 764 Default: 512 765 766What: /sys/fs/f2fs/<disk>/last_age_weight 767Date: January 2023 768Contact: "Ping Xiong" <xiongping1@xiaomi.com> 769Description: When DATA SEPARATION is on, it controls the weight of last data block age. 770 771What: /sys/fs/f2fs/<disk>/compress_watermark 772Date: February 2023 773Contact: "Yangtao Li" <frank.li@vivo.com> 774Description: When compress cache is on, it controls free memory watermark 775 in order to limit caching compress page. If free memory is lower 776 than watermark, then deny caching compress page. The value should be in 777 range of (0, 100], by default it was initialized as 20(%). 778 779What: /sys/fs/f2fs/<disk>/compress_percent 780Date: February 2023 781Contact: "Yangtao Li" <frank.li@vivo.com> 782Description: When compress cache is on, it controls cached page 783 percent(compress pages / free_ram) in order to limit caching compress page. 784 If cached page percent exceed threshold, then deny caching compress page. 785 The value should be in range of (0, 100], by default it was initialized 786 as 20(%). 787 788What: /sys/fs/f2fs/<disk>/discard_io_aware 789Date: November 2023 790Contact: "Chao Yu" <chao@kernel.org> 791Description: It controls to enable/disable IO aware feature for background discard. 792 By default, the value is 1 which indicates IO aware is on. 793 794What: /sys/fs/f2fs/<disk>/blkzone_alloc_policy 795Date: July 2024 796Contact: "Yuanhong Liao" <liaoyuanhong@vivo.com> 797Description: The zone UFS we are currently using consists of two parts: 798 conventional zones and sequential zones. It can be used to control which part 799 to prioritize for writes, with a default value of 0. 800 801 ======================== ========================================= 802 value description 803 blkzone_alloc_policy = 0 Prioritize writing to sequential zones 804 blkzone_alloc_policy = 1 Only allow writing to sequential zones 805 blkzone_alloc_policy = 2 Prioritize writing to conventional zones 806 ======================== ========================================= 807 808What: /sys/fs/f2fs/<disk>/migration_window_granularity 809Date: September 2024 810Contact: "Daeho Jeong" <daehojeong@google.com> 811Description: Controls migration window granularity of garbage collection on large 812 section. it can control the scanning window granularity for GC migration 813 in a unit of segment, while migration_granularity controls the number 814 of segments which can be migrated at the same turn. 815 816What: /sys/fs/f2fs/<disk>/reserved_segments 817Date: September 2024 818Contact: "Daeho Jeong" <daehojeong@google.com> 819Description: In order to fine tune GC behavior, we can control the number of 820 reserved segments. 821 822What: /sys/fs/f2fs/<disk>/gc_no_zoned_gc_percent 823Date: September 2024 824Contact: "Daeho Jeong" <daehojeong@google.com> 825Description: If the percentage of free sections over total sections is above this 826 number, F2FS do not garbage collection for zoned devices through the 827 background GC thread. the default number is "60". 828 829What: /sys/fs/f2fs/<disk>/gc_boost_zoned_gc_percent 830Date: September 2024 831Contact: "Daeho Jeong" <daehojeong@google.com> 832Description: If the percentage of free sections over total sections is under this 833 number, F2FS boosts garbage collection for zoned devices through the 834 background GC thread. the default number is "25". 835 836What: /sys/fs/f2fs/<disk>/gc_valid_thresh_ratio 837Date: September 2024 838Contact: "Daeho Jeong" <daehojeong@google.com> 839Description: It controls the valid block ratio threshold not to trigger excessive GC 840 for zoned devices. The initial value of it is 95(%). F2FS will stop the 841 background GC thread from initiating GC for sections having valid blocks 842 exceeding the ratio. 843 844What: /sys/fs/f2fs/<disk>/max_read_extent_count 845Date: November 2024 846Contact: "Chao Yu" <chao@kernel.org> 847Description: It controls max read extent count for per-inode, the value of threshold 848 is 10240 by default. 849 850What: /sys/fs/f2fs/tuning/reclaim_caches_kb 851Date: February 2025 852Contact: "Jaegeuk Kim" <jaegeuk@kernel.org> 853Description: It reclaims the given KBs of file-backed pages registered by 854 ioctl(F2FS_IOC_DONATE_RANGE). 855 For example, writing N tries to drop N KBs spaces in LRU. 856 857What: /sys/fs/f2fs/<disk>/carve_out 858Date: March 2025 859Contact: "Daeho Jeong" <daehojeong@google.com> 860Description: For several zoned storage devices, vendors will provide extra space which 861 was used for device level GC than specs and F2FS can use this space for 862 filesystem level GC. To do that, we can reserve the space using 863 reserved_blocks. However, it is not enough, since this extra space should 864 not be shown to users. So, with this new sysfs node, we can hide the space 865 by subtracting reserved_blocks from total bytes. 866 867What: /sys/fs/f2fs/<disk>/encoding_flags 868Date: April 2025 869Contact: "Chao Yu" <chao@kernel.org> 870Description: This is a read-only entry to show the value of sb.s_encoding_flags, the 871 value is hexadecimal. 872 873 ============================ ========== 874 Flag_Name Flag_Value 875 ============================ ========== 876 SB_ENC_STRICT_MODE_FL 0x00000001 877 SB_ENC_NO_COMPAT_FALLBACK_FL 0x00000002 878 ============================ ========== 879 880What: /sys/fs/f2fs/<disk>/reserved_pin_section 881Date: June 2025 882Contact: "Chao Yu" <chao@kernel.org> 883Description: This threshold is used to control triggering garbage collection while 884 fallocating on pinned file, so, it can guarantee there is enough free 885 reserved section before preallocating on pinned file. 886 By default, the value is ovp_sections, especially, for zoned ufs, the 887 value is 1. 888 889What: /sys/fs/f2fs/<disk>/gc_boost_gc_multiple 890Date: June 2025 891Contact: "Daeho Jeong" <daehojeong@google.com> 892Description: Set a multiplier for the background GC migration window when F2FS GC is 893 boosted. The range should be from 1 to the segment count in a section. 894 Default: 5 895 896What: /sys/fs/f2fs/<disk>/gc_boost_gc_greedy 897Date: June 2025 898Contact: "Daeho Jeong" <daehojeong@google.com> 899Description: Control GC algorithm for boost GC. 0: cost benefit, 1: greedy 900 Default: 1 901 902What: /sys/fs/f2fs/<disk>/effective_lookup_mode 903Date: August 2025 904Contact: "Daniel Lee" <chullee@google.com> 905Description: 906 This is a read-only entry to show the effective directory lookup mode 907 F2FS is currently using for casefolded directories. 908 This considers both the "lookup_mode" mount option and the on-disk 909 encoding flag, SB_ENC_NO_COMPAT_FALLBACK_FL. 910 911 Possible values are: 912 - "perf": Hash-only lookup. 913 - "compat": Hash-based lookup with a linear search fallback enabled 914 - "auto:perf": lookup_mode is auto and fallback is disabled on-disk 915 - "auto:compat": lookup_mode is auto and fallback is enabled on-disk 916 917What: /sys/fs/f2fs/<disk>/bggc_io_aware 918Date: August 2025 919Contact: "Liao Yuanhong" <liaoyuanhong@vivo.com> 920Description: Used to adjust the BG_GC priority when pending IO, with a default value 921 of 0. Specifically, for ZUFS, the default value is 1. 922 923 ================== ====================================================== 924 value description 925 bggc_io_aware = 0 skip background GC if there is any kind of pending IO 926 bggc_io_aware = 1 skip background GC if there is pending read IO 927 bggc_io_aware = 2 don't aware IO for background GC 928 ================== ====================================================== 929 930What: /sys/fs/f2fs/<disk>/allocate_section_hint 931Date: August 2025 932Contact: "Liao Yuanhong" <liaoyuanhong@vivo.com> 933Description: Indicates the hint section between the first device and others in multi-devices 934 setup. It defaults to the end of the first device in sections. For a single storage 935 device, it defaults to the total number of sections. It can be manually set to match 936 scenarios where multi-devices are mapped to the same dm device. 937 938What: /sys/fs/f2fs/<disk>/allocate_section_policy 939Date: August 2025 940Contact: "Liao Yuanhong" <liaoyuanhong@vivo.com> 941Description: Controls write priority in multi-devices setups. A value of 0 means normal writing. 942 A value of 1 prioritizes writing to devices before the allocate_section_hint. A value of 2 943 prioritizes writing to devices after the allocate_section_hint. The default is 0. 944 945 =========================== ========================================================== 946 value description 947 allocate_section_policy = 0 Normal writing 948 allocate_section_policy = 1 Prioritize writing to section before allocate_section_hint 949 allocate_section_policy = 2 Prioritize writing to section after allocate_section_hint 950 =========================== ========================================================== 951 952What: /sys/fs/f2fs/<disk>/max_lock_elapsed_time 953Date: December 2025 954Contact: "Chao Yu" <chao@kernel.org> 955Description: This is a threshold, once a thread enters critical region that lock covers, total 956 elapsed time exceeds this threshold, f2fs will print tracepoint to dump information 957 of related context. This sysfs entry can be used to control the value of threshold, 958 by default, the value is 500 ms. 959 960What: /sys/fs/f2fs/<disk>/inject_timeout_type 961Date: December 2025 962Contact: "Chao Yu" <chao@kernel.org> 963Description: This sysfs entry can be used to change type of injected timeout: 964 ========== =============================== 965 Flag_Value Flag_Description 966 ========== =============================== 967 0x00000000 No timeout (default) 968 0x00000001 Simulate running time 969 0x00000002 Simulate IO type sleep time 970 0x00000003 Simulate Non-IO type sleep time 971 0x00000004 Simulate runnable time 972 ========== =============================== 973 974What: /sys/fs/f2fs/<disk>/adjust_lock_priority 975Date: January 2026 976Contact: "Chao Yu" <chao@kernel.org> 977Description: This sysfs entry can be used to enable/disable to adjust priority for task 978 which is in critical region covered by lock. 979 ========== ================== 980 Flag_Value Flag_Description 981 ========== ================== 982 0x00000000 Disabled (default) 983 0x00000001 cp_rwsem 984 0x00000002 node_change 985 0x00000004 node_write 986 0x00000008 gc_lock 987 0x00000010 cp_global 988 0x00000020 io_rwsem 989 0x00000040 nat_tree_lock 990 ========== ================== 991 992What: /sys/fs/f2fs/<disk>/lock_duration_priority 993Date: January 2026 994Contact: "Chao Yu" <chao@kernel.org> 995Description: f2fs can tune priority of thread which has entered into critical region covered by 996 f2fs rwsemphore lock. This sysfs entry can be used to control priority value, the 997 range is [100,139], by default the value is 120. 998 999What: /sys/fs/f2fs/<disk>/critical_task_priority 1000Date: February 2026 1001Contact: "Chao Yu" <chao@kernel.org> 1002Description: It can be used to tune priority of f2fs critical task, e.g. f2fs_ckpt, f2fs_gc 1003 threads, limitation as below: 1004 - it requires user has CAP_SYS_NICE capability. 1005 - the range is [100, 139], by default the value is 120. 1006 1007What: /sys/fs/f2fs/<disk>/max_atc_write_bio_size 1008Date: June 2026 1009Contact: Bart Van Assche <bvanassche@acm.org> 1010Description: Every time a write operation completes f2fs_write_end_io() is 1011 called. This function may be called from an atomic context, 1012 e.g. from inside an interrupt handler. This attribute controls 1013 the maximum size of a write bio that is completed in atomic 1014 (atc) context. The default value for this attribute is UINT_MAX 1015 which means that this functionality is disabled by default. 1016 1017What: /sys/fs/f2fs/<disk>/pinned_area_max_secno 1018Date: August 2026 1019Contact: "Daeho Jeong" <daehojeong@google.com> 1020Description: This is a read-only entry to show the upper bound section number 1021 for pinned files. Pinned files will only be allocated within 1022 sections 0 to pinned_area_max_secno - 1. 1023