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Diffstat (limited to 'Documentation/filesystems/f2fs.rst')
| -rw-r--r-- | Documentation/filesystems/f2fs.rst | 126 |
1 files changed, 102 insertions, 24 deletions
diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst index efc3493fd6f8..440e4ae74e44 100644 --- a/Documentation/filesystems/f2fs.rst +++ b/Documentation/filesystems/f2fs.rst @@ -182,31 +182,34 @@ fault_type=%d Support configuring fault injection type, should be enabled with fault_injection option, fault type value is shown below, it supports single or combined type. - =========================== =========== + =========================== ========== Type_Name Type_Value - =========================== =========== - FAULT_KMALLOC 0x000000001 - FAULT_KVMALLOC 0x000000002 - FAULT_PAGE_ALLOC 0x000000004 - FAULT_PAGE_GET 0x000000008 - FAULT_ALLOC_BIO 0x000000010 (obsolete) - FAULT_ALLOC_NID 0x000000020 - FAULT_ORPHAN 0x000000040 - FAULT_BLOCK 0x000000080 - FAULT_DIR_DEPTH 0x000000100 - FAULT_EVICT_INODE 0x000000200 - FAULT_TRUNCATE 0x000000400 - FAULT_READ_IO 0x000000800 - FAULT_CHECKPOINT 0x000001000 - FAULT_DISCARD 0x000002000 - FAULT_WRITE_IO 0x000004000 - FAULT_SLAB_ALLOC 0x000008000 - FAULT_DQUOT_INIT 0x000010000 - FAULT_LOCK_OP 0x000020000 - FAULT_BLKADDR_VALIDITY 0x000040000 - FAULT_BLKADDR_CONSISTENCE 0x000080000 - FAULT_NO_SEGMENT 0x000100000 - =========================== =========== + =========================== ========== + FAULT_KMALLOC 0x00000001 + FAULT_KVMALLOC 0x00000002 + FAULT_PAGE_ALLOC 0x00000004 + FAULT_PAGE_GET 0x00000008 + FAULT_ALLOC_BIO 0x00000010 (obsolete) + FAULT_ALLOC_NID 0x00000020 + FAULT_ORPHAN 0x00000040 + FAULT_BLOCK 0x00000080 + FAULT_DIR_DEPTH 0x00000100 + FAULT_EVICT_INODE 0x00000200 + FAULT_TRUNCATE 0x00000400 + FAULT_READ_IO 0x00000800 + FAULT_CHECKPOINT 0x00001000 + FAULT_DISCARD 0x00002000 + FAULT_WRITE_IO 0x00004000 + FAULT_SLAB_ALLOC 0x00008000 + FAULT_DQUOT_INIT 0x00010000 + FAULT_LOCK_OP 0x00020000 + FAULT_BLKADDR_VALIDITY 0x00040000 + FAULT_BLKADDR_CONSISTENCE 0x00080000 + FAULT_NO_SEGMENT 0x00100000 + FAULT_INCONSISTENT_FOOTER 0x00200000 + FAULT_TIMEOUT 0x00400000 (1000ms) + FAULT_VMALLOC 0x00800000 + =========================== ========== mode=%s Control block allocation mode which supports "adaptive" and "lfs". In "lfs" mode, there should be no random writes towards main area. @@ -365,6 +368,8 @@ errors=%s Specify f2fs behavior on critical errors. This supports modes: pending node write drop keep N/A pending meta write keep keep N/A ====================== =============== =============== ======== +nat_bits Enable nat_bits feature to enhance full/empty nat blocks access, + by default it's disabled. ======================== ============================================================ Debugfs Entries @@ -774,6 +779,35 @@ 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 +----------------- + +F2FS sets the whint all the time with the below policy. + +===================== ======================== =================== +User F2FS Block +===================== ======================== =================== +N/A META WRITE_LIFE_NONE|REQ_META +N/A HOT_NODE WRITE_LIFE_NONE +N/A WARM_NODE WRITE_LIFE_MEDIUM +N/A COLD_NODE WRITE_LIFE_LONG +ioctl(COLD) COLD_DATA WRITE_LIFE_EXTREME +extension list " " + +-- buffered io +N/A COLD_DATA WRITE_LIFE_EXTREME +N/A HOT_DATA WRITE_LIFE_SHORT +N/A WARM_DATA WRITE_LIFE_NOT_SET + +-- 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 ------------------- @@ -914,3 +948,47 @@ NVMe Zoned Namespace devices can start before the zone-capacity and span across zone-capacity boundary. Such spanning segments are also considered as usable segments. All blocks past the zone-capacity are considered unusable in these segments. + +Device aliasing feature +----------------------- + +f2fs can utilize a special file called a "device aliasing file." This file allows +the entire storage device to be mapped with a single, large extent, not using +the usual f2fs node structures. This mapped area is pinned and primarily intended +for holding the space. + +Essentially, this mechanism allows a portion of the f2fs area to be temporarily +reserved and used by another filesystem or for different purposes. Once that +external usage is complete, the device aliasing file can be deleted, releasing +the reserved space back to F2FS for its own use. + +<use-case> + +# ls /dev/vd* +/dev/vdb (32GB) /dev/vdc (32GB) +# mkfs.ext4 /dev/vdc +# mkfs.f2fs -c /dev/vdc@vdc.file /dev/vdb +# mount /dev/vdb /mnt/f2fs +# ls -l /mnt/f2fs +vdc.file +# df -h +/dev/vdb 64G 33G 32G 52% /mnt/f2fs + +# mount -o loop /dev/vdc /mnt/ext4 +# df -h +/dev/vdb 64G 33G 32G 52% /mnt/f2fs +/dev/loop7 32G 24K 30G 1% /mnt/ext4 +# umount /mnt/ext4 + +# f2fs_io getflags /mnt/f2fs/vdc.file +get a flag on /mnt/f2fs/vdc.file ret=0, flags=nocow(pinned),immutable +# f2fs_io setflags noimmutable /mnt/f2fs/vdc.file +get a flag on noimmutable ret=0, flags=800010 +set a flag on /mnt/f2fs/vdc.file ret=0, flags=noimmutable +# rm /mnt/f2fs/vdc.file +# df -h +/dev/vdb 64G 753M 64G 2% /mnt/f2fs + +So, the key idea is, user can do any file operations on /dev/vdc, and +reclaim the space after the use, while the space is counted as /data. +That doesn't require modifying partition size and filesystem format. |