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Diffstat (limited to 'Documentation/filesystems/f2fs.rst')
| -rw-r--r-- | Documentation/filesystems/f2fs.rst | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst index 09de6ebbbdfa..d7b84695f56a 100644 --- a/Documentation/filesystems/f2fs.rst +++ b/Documentation/filesystems/f2fs.rst @@ -197,10 +197,29 @@ fault_type=%d Support configuring fault injection type, should be FAULT_DISCARD 0x000002000 FAULT_WRITE_IO 0x000004000 FAULT_SLAB_ALLOC 0x000008000 + FAULT_DQUOT_INIT 0x000010000 =================== =========== mode=%s Control block allocation mode which supports "adaptive" and "lfs". In "lfs" mode, there should be no random writes towards main area. + "fragment:segment" and "fragment:block" are newly added here. + These are developer options for experiments to simulate filesystem + fragmentation/after-GC situation itself. The developers use these + modes to understand filesystem fragmentation/after-GC condition well, + and eventually get some insights to handle them better. + In "fragment:segment", f2fs allocates a new segment in ramdom + position. With this, we can simulate the after-GC condition. + In "fragment:block", we can scatter block allocation with + "max_fragment_chunk" and "max_fragment_hole" sysfs nodes. + We added some randomness to both chunk and hole size to make + it close to realistic IO pattern. So, in this mode, f2fs will allocate + 1..<max_fragment_chunk> blocks in a chunk and make a hole in the + length of 1..<max_fragment_hole> by turns. With this, the newly + allocated blocks will be scattered throughout the whole partition. + Note that "fragment:block" implicitly enables "fragment:segment" + option for more randomness. + Please, use these options for your experiments and we strongly + recommend to re-format the filesystem after using these options. io_bits=%u Set the bit size of write IO requests. It should be set with "mode=lfs". usrquota Enable plain user disk quota accounting. @@ -283,7 +302,7 @@ compress_extension=%s Support adding specified extension, so that f2fs can enab For other files, we can still enable compression via ioctl. Note that, there is one reserved special extension '*', it can be set to enable compression for all files. -nocompress_extension=%s Support adding specified extension, so that f2fs can disable +nocompress_extension=%s Support adding specified extension, so that f2fs can disable compression on those corresponding files, just contrary to compression extension. If you know exactly which files cannot be compressed, you can use this. The same extension name can't appear in both compress and nocompress |