diff options
Diffstat (limited to 'Documentation/filesystems/f2fs.rst')
| -rw-r--r-- | Documentation/filesystems/f2fs.rst | 94 |
1 files changed, 15 insertions, 79 deletions
diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst index d7b84695f56a..17df9a02ccff 100644 --- a/Documentation/filesystems/f2fs.rst +++ b/Documentation/filesystems/f2fs.rst @@ -198,6 +198,7 @@ fault_type=%d Support configuring fault injection type, should be FAULT_WRITE_IO 0x000004000 FAULT_SLAB_ALLOC 0x000008000 FAULT_DQUOT_INIT 0x000010000 + FAULT_LOCK_OP 0x000020000 =================== =========== mode=%s Control block allocation mode which supports "adaptive" and "lfs". In "lfs" mode, there should be no random @@ -234,12 +235,6 @@ offgrpjquota Turn off group journalled quota. offprjjquota Turn off project journalled quota. quota Enable plain user disk quota accounting. noquota Disable all plain disk quota option. -whint_mode=%s Control which write hints are passed down to block - layer. This supports "off", "user-based", and - "fs-based". In "off" mode (default), f2fs does not pass - down hints. In "user-based" mode, f2fs tries to pass - down hints given by users. And in "fs-based" mode, f2fs - passes down hints with its policy. alloc_mode=%s Adjust block allocation policy, which supports "reuse" and "default". fsync_mode=%s Control the policy of fsync. Currently supports "posix", @@ -291,9 +286,8 @@ compress_algorithm=%s:%d Control compress algorithm and its compress level, now, algorithm level range lz4 3 - 16 zstd 1 - 22 -compress_log_size=%u Support configuring compress cluster size, the size will - be 4KB * (1 << %u), 16KB is minimum size, also it's - default size. +compress_log_size=%u Support configuring compress cluster size. The size will + be 4KB * (1 << %u). The default and minimum sizes are 16KB. compress_extension=%s Support adding specified extension, so that f2fs can enable compression on those corresponding files, e.g. if all files with '.ext' has high compression rate, we can set the '.ext' @@ -341,6 +335,11 @@ discard_unit=%s Control discard unit, the argument can be "block", "segment" default, it is helpful for large sized SMR or ZNS devices to reduce memory cost by getting rid of fs metadata supports small discard. +memory=%s Control memory mode. This supports "normal" and "low" modes. + "low" mode is introduced to support low memory devices. + Because of the nature of low memory devices, in this mode, f2fs + will try to save memory sometimes by sacrificing performance. + "normal" mode is the default mode and same as before. ======================== ============================================================ Debugfs Entries @@ -750,70 +749,6 @@ In order to identify whether the data in the victim segment are valid or not, F2FS manages a bitmap. Each bit represents the validity of a block, and the bitmap is composed of a bit stream covering whole blocks in main area. -Write-hint Policy ------------------ - -1) whint_mode=off. F2FS only passes down WRITE_LIFE_NOT_SET. - -2) whint_mode=user-based. F2FS tries to pass down hints given by -users. - -===================== ======================== =================== -User F2FS Block -===================== ======================== =================== -N/A META WRITE_LIFE_NOT_SET -N/A HOT_NODE " -N/A WARM_NODE " -N/A COLD_NODE " -ioctl(COLD) COLD_DATA WRITE_LIFE_EXTREME -extension list " " - --- buffered io -WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME -WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT -WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_NOT_SET -WRITE_LIFE_NONE " " -WRITE_LIFE_MEDIUM " " -WRITE_LIFE_LONG " " - --- direct io -WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME -WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT -WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_NOT_SET -WRITE_LIFE_NONE " WRITE_LIFE_NONE -WRITE_LIFE_MEDIUM " WRITE_LIFE_MEDIUM -WRITE_LIFE_LONG " WRITE_LIFE_LONG -===================== ======================== =================== - -3) whint_mode=fs-based. F2FS passes down hints with its policy. - -===================== ======================== =================== -User F2FS Block -===================== ======================== =================== -N/A META WRITE_LIFE_MEDIUM; -N/A HOT_NODE WRITE_LIFE_NOT_SET -N/A WARM_NODE " -N/A COLD_NODE WRITE_LIFE_NONE -ioctl(COLD) COLD_DATA WRITE_LIFE_EXTREME -extension list " " - --- buffered io -WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME -WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT -WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_LONG -WRITE_LIFE_NONE " " -WRITE_LIFE_MEDIUM " " -WRITE_LIFE_LONG " " - --- direct io -WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME -WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT -WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_NOT_SET -WRITE_LIFE_NONE " WRITE_LIFE_NONE -WRITE_LIFE_MEDIUM " WRITE_LIFE_MEDIUM -WRITE_LIFE_LONG " WRITE_LIFE_LONG -===================== ======================== =================== - Fallocate(2) Policy ------------------- @@ -887,10 +822,11 @@ Compression implementation Instead, the main goal is to reduce data writes to flash disk as much as possible, resulting in extending disk life time as well as relaxing IO congestion. Alternatively, we've added ioctl(F2FS_IOC_RELEASE_COMPRESS_BLOCKS) - interface to reclaim compressed space and show it to user after putting the - immutable bit. Immutable bit, after release, it doesn't allow writing/mmaping - on the file, until reserving compressed space via - ioctl(F2FS_IOC_RESERVE_COMPRESS_BLOCKS) or truncating filesize to zero. + interface to reclaim compressed space and show it to user after setting a + special flag to the inode. Once the compressed space is released, the flag + will block writing data to the file until either the compressed space is + reserved via ioctl(F2FS_IOC_RESERVE_COMPRESS_BLOCKS) or the file size is + truncated to zero. Compress metadata layout:: @@ -899,12 +835,12 @@ Compress metadata layout:: | cluster 1 | cluster 2 | ......... | cluster N | +-----------------------------------------------+ . . . . - . . . . + . . . . . Compressed Cluster . . Normal Cluster . +----------+---------+---------+---------+ +---------+---------+---------+---------+ |compr flag| block 1 | block 2 | block 3 | | block 1 | block 2 | block 3 | block 4 | +----------+---------+---------+---------+ +---------+---------+---------+---------+ - . . + . . . . . . +-------------+-------------+----------+----------------------------+ |