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629 lines
17 KiB
629 lines
17 KiB
/*
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* fs/logfs/logfs_abi.h
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*
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* As should be obvious for Linux kernel code, license is GPLv2
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*
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* Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
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*
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* Public header for logfs.
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*/
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#ifndef FS_LOGFS_LOGFS_ABI_H
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#define FS_LOGFS_LOGFS_ABI_H
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/* For out-of-kernel compiles */
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#ifndef BUILD_BUG_ON
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#define BUILD_BUG_ON(condition) /**/
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#endif
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#define SIZE_CHECK(type, size) \
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static inline void check_##type(void) \
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{ \
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BUILD_BUG_ON(sizeof(struct type) != (size)); \
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}
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/*
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* Throughout the logfs code, we're constantly dealing with blocks at
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* various positions or offsets. To remove confusion, we stricly
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* distinguish between a "position" - the logical position within a
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* file and an "offset" - the physical location within the device.
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*
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* Any usage of the term offset for a logical location or position for
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* a physical one is a bug and should get fixed.
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*/
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/*
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* Block are allocated in one of several segments depending on their
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* level. The following levels are used:
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* 0 - regular data block
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* 1 - i1 indirect blocks
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* 2 - i2 indirect blocks
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* 3 - i3 indirect blocks
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* 4 - i4 indirect blocks
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* 5 - i5 indirect blocks
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* 6 - ifile data blocks
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* 7 - ifile i1 indirect blocks
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* 8 - ifile i2 indirect blocks
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* 9 - ifile i3 indirect blocks
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* 10 - ifile i4 indirect blocks
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* 11 - ifile i5 indirect blocks
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* Potential levels to be used in the future:
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* 12 - gc recycled blocks, long-lived data
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* 13 - replacement blocks, short-lived data
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*
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* Levels 1-11 are necessary for robust gc operations and help separate
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* short-lived metadata from longer-lived file data. In the future,
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* file data should get separated into several segments based on simple
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* heuristics. Old data recycled during gc operation is expected to be
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* long-lived. New data is of uncertain life expectancy. New data
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* used to replace older blocks in existing files is expected to be
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* short-lived.
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*/
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/* Magic numbers. 64bit for superblock, 32bit for statfs f_type */
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#define LOGFS_MAGIC 0x7a3a8e5cb9d5bf67ull
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#define LOGFS_MAGIC_U32 0xc97e8168u
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/*
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* Various blocksize related macros. Blocksize is currently fixed at 4KiB.
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* Sooner or later that should become configurable and the macros replaced
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* by something superblock-dependent. Pointers in indirect blocks are and
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* will remain 64bit.
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*
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* LOGFS_BLOCKSIZE - self-explaining
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* LOGFS_BLOCK_FACTOR - number of pointers per indirect block
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* LOGFS_BLOCK_BITS - log2 of LOGFS_BLOCK_FACTOR, used for shifts
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*/
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#define LOGFS_BLOCKSIZE (4096ull)
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#define LOGFS_BLOCK_FACTOR (LOGFS_BLOCKSIZE / sizeof(u64))
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#define LOGFS_BLOCK_BITS (9)
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/*
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* Number of blocks at various levels of indirection. There are 16 direct
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* block pointers plus a single indirect pointer.
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*/
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#define I0_BLOCKS (16)
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#define I1_BLOCKS LOGFS_BLOCK_FACTOR
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#define I2_BLOCKS (LOGFS_BLOCK_FACTOR * I1_BLOCKS)
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#define I3_BLOCKS (LOGFS_BLOCK_FACTOR * I2_BLOCKS)
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#define I4_BLOCKS (LOGFS_BLOCK_FACTOR * I3_BLOCKS)
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#define I5_BLOCKS (LOGFS_BLOCK_FACTOR * I4_BLOCKS)
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#define INDIRECT_INDEX I0_BLOCKS
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#define LOGFS_EMBEDDED_FIELDS (I0_BLOCKS + 1)
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/*
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* Sizes at which files require another level of indirection. Files smaller
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* than LOGFS_EMBEDDED_SIZE can be completely stored in the inode itself,
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* similar like ext2 fast symlinks.
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*
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* Data at a position smaller than LOGFS_I0_SIZE is accessed through the
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* direct pointers, else through the 1x indirect pointer and so forth.
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*/
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#define LOGFS_EMBEDDED_SIZE (LOGFS_EMBEDDED_FIELDS * sizeof(u64))
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#define LOGFS_I0_SIZE (I0_BLOCKS * LOGFS_BLOCKSIZE)
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#define LOGFS_I1_SIZE (I1_BLOCKS * LOGFS_BLOCKSIZE)
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#define LOGFS_I2_SIZE (I2_BLOCKS * LOGFS_BLOCKSIZE)
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#define LOGFS_I3_SIZE (I3_BLOCKS * LOGFS_BLOCKSIZE)
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#define LOGFS_I4_SIZE (I4_BLOCKS * LOGFS_BLOCKSIZE)
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#define LOGFS_I5_SIZE (I5_BLOCKS * LOGFS_BLOCKSIZE)
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/*
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* Each indirect block pointer must have this flag set, if all block pointers
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* behind it are set, i.e. there is no hole hidden in the shadow of this
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* indirect block pointer.
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*/
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#define LOGFS_FULLY_POPULATED (1ULL << 63)
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#define pure_ofs(ofs) (ofs & ~LOGFS_FULLY_POPULATED)
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/*
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* LogFS needs to separate data into levels. Each level is defined as the
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* maximal possible distance from the master inode (inode of the inode file).
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* Data blocks reside on level 0, 1x indirect block on level 1, etc.
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* Inodes reside on level 6, indirect blocks for the inode file on levels 7-11.
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* This effort is necessary to guarantee garbage collection to always make
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* progress.
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*
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* LOGFS_MAX_INDIRECT is the maximal indirection through indirect blocks,
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* LOGFS_MAX_LEVELS is one more for the actual data level of a file. It is
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* the maximal number of levels for one file.
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* LOGFS_NO_AREAS is twice that, as the inode file and regular files are
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* effectively stacked on top of each other.
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*/
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#define LOGFS_MAX_INDIRECT (5)
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#define LOGFS_MAX_LEVELS (LOGFS_MAX_INDIRECT + 1)
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#define LOGFS_NO_AREAS (2 * LOGFS_MAX_LEVELS)
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/* Maximum size of filenames */
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#define LOGFS_MAX_NAMELEN (255)
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/* Number of segments in the primary journal. */
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#define LOGFS_JOURNAL_SEGS (16)
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/* Maximum number of free/erased/etc. segments in journal entries */
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#define MAX_CACHED_SEGS (64)
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/*
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* LOGFS_OBJECT_HEADERSIZE is the size of a single header in the object store,
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* LOGFS_MAX_OBJECTSIZE the size of the largest possible object, including
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* its header,
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* LOGFS_SEGMENT_RESERVE is the amount of space reserved for each segment for
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* its segment header and the padded space at the end when no further objects
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* fit.
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*/
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#define LOGFS_OBJECT_HEADERSIZE (0x1c)
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#define LOGFS_SEGMENT_HEADERSIZE (0x18)
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#define LOGFS_MAX_OBJECTSIZE (LOGFS_OBJECT_HEADERSIZE + LOGFS_BLOCKSIZE)
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#define LOGFS_SEGMENT_RESERVE \
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(LOGFS_SEGMENT_HEADERSIZE + LOGFS_MAX_OBJECTSIZE - 1)
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/*
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* Segment types:
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* SEG_SUPER - Data or indirect block
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* SEG_JOURNAL - Inode
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* SEG_OSTORE - Dentry
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*/
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enum {
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SEG_SUPER = 0x01,
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SEG_JOURNAL = 0x02,
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SEG_OSTORE = 0x03,
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};
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/**
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* struct logfs_segment_header - per-segment header in the ostore
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*
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* @crc: crc32 of header (there is no data)
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* @pad: unused, must be 0
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* @type: segment type, see above
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* @level: GC level for all objects in this segment
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* @segno: segment number
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* @ec: erase count for this segment
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* @gec: global erase count at time of writing
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*/
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struct logfs_segment_header {
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__be32 crc;
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__be16 pad;
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__u8 type;
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__u8 level;
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__be32 segno;
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__be32 ec;
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__be64 gec;
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};
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SIZE_CHECK(logfs_segment_header, LOGFS_SEGMENT_HEADERSIZE);
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#define LOGFS_FEATURES_INCOMPAT (0ull)
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#define LOGFS_FEATURES_RO_COMPAT (0ull)
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#define LOGFS_FEATURES_COMPAT (0ull)
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/**
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* struct logfs_disk_super - on-medium superblock
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*
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* @ds_magic: magic number, must equal LOGFS_MAGIC
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* @ds_crc: crc32 of structure starting with the next field
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* @ds_ifile_levels: maximum number of levels for ifile
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* @ds_iblock_levels: maximum number of levels for regular files
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* @ds_data_levels: number of separate levels for data
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* @pad0: reserved, must be 0
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* @ds_feature_incompat: incompatible filesystem features
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* @ds_feature_ro_compat: read-only compatible filesystem features
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* @ds_feature_compat: compatible filesystem features
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* @ds_flags: flags
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* @ds_segment_shift: log2 of segment size
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* @ds_block_shift: log2 of block size
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* @ds_write_shift: log2 of write size
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* @pad1: reserved, must be 0
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* @ds_journal_seg: segments used by primary journal
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* @ds_root_reserve: bytes reserved for the superuser
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* @ds_speed_reserve: bytes reserved to speed up GC
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* @ds_bad_seg_reserve: number of segments reserved to handle bad blocks
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* @pad2: reserved, must be 0
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* @pad3: reserved, must be 0
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*
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* Contains only read-only fields. Read-write fields like the amount of used
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* space is tracked in the dynamic superblock, which is stored in the journal.
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*/
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struct logfs_disk_super {
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struct logfs_segment_header ds_sh;
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__be64 ds_magic;
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__be32 ds_crc;
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__u8 ds_ifile_levels;
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__u8 ds_iblock_levels;
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__u8 ds_data_levels;
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__u8 ds_segment_shift;
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__u8 ds_block_shift;
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__u8 ds_write_shift;
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__u8 pad0[6];
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__be64 ds_filesystem_size;
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__be32 ds_segment_size;
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__be32 ds_bad_seg_reserve;
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__be64 ds_feature_incompat;
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__be64 ds_feature_ro_compat;
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__be64 ds_feature_compat;
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__be64 ds_feature_flags;
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__be64 ds_root_reserve;
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__be64 ds_speed_reserve;
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__be32 ds_journal_seg[LOGFS_JOURNAL_SEGS];
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__be64 ds_super_ofs[2];
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__be64 pad3[8];
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};
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SIZE_CHECK(logfs_disk_super, 256);
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/*
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* Object types:
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* OBJ_BLOCK - Data or indirect block
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* OBJ_INODE - Inode
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* OBJ_DENTRY - Dentry
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*/
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enum {
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OBJ_BLOCK = 0x04,
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OBJ_INODE = 0x05,
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OBJ_DENTRY = 0x06,
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};
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/**
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* struct logfs_object_header - per-object header in the ostore
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*
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* @crc: crc32 of header, excluding data_crc
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* @len: length of data
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* @type: object type, see above
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* @compr: compression type
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* @ino: inode number
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* @bix: block index
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* @data_crc: crc32 of payload
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*/
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struct logfs_object_header {
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__be32 crc;
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__be16 len;
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__u8 type;
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__u8 compr;
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__be64 ino;
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__be64 bix;
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__be32 data_crc;
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} __attribute__((packed));
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SIZE_CHECK(logfs_object_header, LOGFS_OBJECT_HEADERSIZE);
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/*
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* Reserved inode numbers:
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* LOGFS_INO_MASTER - master inode (for inode file)
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* LOGFS_INO_ROOT - root directory
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* LOGFS_INO_SEGFILE - per-segment used bytes and erase count
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*/
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enum {
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LOGFS_INO_MAPPING = 0x00,
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LOGFS_INO_MASTER = 0x01,
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LOGFS_INO_ROOT = 0x02,
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LOGFS_INO_SEGFILE = 0x03,
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LOGFS_RESERVED_INOS = 0x10,
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};
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/*
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* Inode flags. High bits should never be written to the medium. They are
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* reserved for in-memory usage.
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* Low bits should either remain in sync with the corresponding FS_*_FL or
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* reuse slots that obviously don't make sense for logfs.
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*
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* LOGFS_IF_DIRTY Inode must be written back
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* LOGFS_IF_ZOMBIE Inode has been deleted
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* LOGFS_IF_STILLBORN -ENOSPC happened when creating inode
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*/
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#define LOGFS_IF_COMPRESSED 0x00000004 /* == FS_COMPR_FL */
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#define LOGFS_IF_DIRTY 0x20000000
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#define LOGFS_IF_ZOMBIE 0x40000000
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#define LOGFS_IF_STILLBORN 0x80000000
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/* Flags available to chattr */
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#define LOGFS_FL_USER_VISIBLE (LOGFS_IF_COMPRESSED)
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#define LOGFS_FL_USER_MODIFIABLE (LOGFS_IF_COMPRESSED)
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/* Flags inherited from parent directory on file/directory creation */
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#define LOGFS_FL_INHERITED (LOGFS_IF_COMPRESSED)
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/**
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* struct logfs_disk_inode - on-medium inode
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*
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* @di_mode: file mode
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* @di_pad: reserved, must be 0
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* @di_flags: inode flags, see above
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* @di_uid: user id
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* @di_gid: group id
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* @di_ctime: change time
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* @di_mtime: modify time
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* @di_refcount: reference count (aka nlink or link count)
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* @di_generation: inode generation, for nfs
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* @di_used_bytes: number of bytes used
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* @di_size: file size
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* @di_data: data pointers
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*/
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struct logfs_disk_inode {
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__be16 di_mode;
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__u8 di_height;
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__u8 di_pad;
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__be32 di_flags;
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__be32 di_uid;
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__be32 di_gid;
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__be64 di_ctime;
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__be64 di_mtime;
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__be64 di_atime;
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__be32 di_refcount;
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__be32 di_generation;
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__be64 di_used_bytes;
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__be64 di_size;
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__be64 di_data[LOGFS_EMBEDDED_FIELDS];
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};
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SIZE_CHECK(logfs_disk_inode, 200);
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#define INODE_POINTER_OFS \
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(offsetof(struct logfs_disk_inode, di_data) / sizeof(__be64))
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#define INODE_USED_OFS \
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(offsetof(struct logfs_disk_inode, di_used_bytes) / sizeof(__be64))
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#define INODE_SIZE_OFS \
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(offsetof(struct logfs_disk_inode, di_size) / sizeof(__be64))
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#define INODE_HEIGHT_OFS (0)
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/**
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* struct logfs_disk_dentry - on-medium dentry structure
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*
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* @ino: inode number
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* @namelen: length of file name
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* @type: file type, identical to bits 12..15 of mode
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* @name: file name
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*/
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/* FIXME: add 6 bytes of padding to remove the __packed */
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struct logfs_disk_dentry {
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__be64 ino;
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__be16 namelen;
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__u8 type;
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__u8 name[LOGFS_MAX_NAMELEN];
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} __attribute__((packed));
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SIZE_CHECK(logfs_disk_dentry, 266);
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#define RESERVED 0xffffffff
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#define BADSEG 0xffffffff
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/**
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* struct logfs_segment_entry - segment file entry
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*
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* @ec_level: erase count and level
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* @valid: number of valid bytes
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*
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* Segment file contains one entry for every segment. ec_level contains the
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* erasecount in the upper 28 bits and the level in the lower 4 bits. An
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* ec_level of BADSEG (-1) identifies bad segments. valid contains the number
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* of valid bytes or RESERVED (-1 again) if the segment is used for either the
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* superblock or the journal, or when the segment is bad.
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*/
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struct logfs_segment_entry {
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__be32 ec_level;
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__be32 valid;
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};
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SIZE_CHECK(logfs_segment_entry, 8);
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/**
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* struct logfs_journal_header - header for journal entries (JEs)
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*
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* @h_crc: crc32 of journal entry
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* @h_len: length of compressed journal entry,
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* not including header
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* @h_datalen: length of uncompressed data
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* @h_type: JE type
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* @h_compr: compression type
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* @h_pad: reserved
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*/
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struct logfs_journal_header {
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__be32 h_crc;
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__be16 h_len;
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__be16 h_datalen;
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__be16 h_type;
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__u8 h_compr;
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__u8 h_pad[5];
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};
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SIZE_CHECK(logfs_journal_header, 16);
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|
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/*
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* Life expectency of data.
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* VIM_DEFAULT - default vim
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* VIM_SEGFILE - for segment file only - very short-living
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* VIM_GC - GC'd data - likely long-living
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*/
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enum logfs_vim {
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VIM_DEFAULT = 0,
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VIM_SEGFILE = 1,
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};
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/**
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* struct logfs_je_area - wbuf header
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*
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* @segno: segment number of area
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* @used_bytes: number of bytes already used
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* @gc_level: GC level
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* @vim: life expectancy of data
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*
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* "Areas" are segments currently being used for writing. There is at least
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* one area per GC level. Several may be used to separate long-living from
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* short-living data. If an area with unknown vim is encountered, it can
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* simply be closed.
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* The write buffer immediately follow this header.
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*/
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struct logfs_je_area {
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__be32 segno;
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__be32 used_bytes;
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__u8 gc_level;
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__u8 vim;
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} __attribute__((packed));
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SIZE_CHECK(logfs_je_area, 10);
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#define MAX_JOURNAL_HEADER \
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(sizeof(struct logfs_journal_header) + sizeof(struct logfs_je_area))
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|
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/**
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* struct logfs_je_dynsb - dynamic superblock
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*
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* @ds_gec: global erase count
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* @ds_sweeper: current position of GC "sweeper"
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* @ds_rename_dir: source directory ino (see dir.c documentation)
|
|
* @ds_rename_pos: position of source dd (see dir.c documentation)
|
|
* @ds_victim_ino: victims of incomplete dir operation (see dir.c)
|
|
* @ds_victim_ino: parent inode of victim (see dir.c)
|
|
* @ds_used_bytes: number of used bytes
|
|
*/
|
|
struct logfs_je_dynsb {
|
|
__be64 ds_gec;
|
|
__be64 ds_sweeper;
|
|
|
|
__be64 ds_rename_dir;
|
|
__be64 ds_rename_pos;
|
|
|
|
__be64 ds_victim_ino;
|
|
__be64 ds_victim_parent; /* XXX */
|
|
|
|
__be64 ds_used_bytes;
|
|
__be32 ds_generation;
|
|
__be32 pad;
|
|
};
|
|
|
|
SIZE_CHECK(logfs_je_dynsb, 64);
|
|
|
|
/**
|
|
* struct logfs_je_anchor - anchor of filesystem tree, aka master inode
|
|
*
|
|
* @da_size: size of inode file
|
|
* @da_last_ino: last created inode
|
|
* @da_used_bytes: number of bytes used
|
|
* @da_data: data pointers
|
|
*/
|
|
struct logfs_je_anchor {
|
|
__be64 da_size;
|
|
__be64 da_last_ino;
|
|
|
|
__be64 da_used_bytes;
|
|
u8 da_height;
|
|
u8 pad[7];
|
|
|
|
__be64 da_data[LOGFS_EMBEDDED_FIELDS];
|
|
};
|
|
|
|
SIZE_CHECK(logfs_je_anchor, 168);
|
|
|
|
/**
|
|
* struct logfs_je_spillout - spillout entry (from 1st to 2nd journal)
|
|
*
|
|
* @so_segment: segments used for 2nd journal
|
|
*
|
|
* Length of the array is given by h_len field in the header.
|
|
*/
|
|
struct logfs_je_spillout {
|
|
__be64 so_segment[0];
|
|
};
|
|
|
|
SIZE_CHECK(logfs_je_spillout, 0);
|
|
|
|
/**
|
|
* struct logfs_je_journal_ec - erase counts for all journal segments
|
|
*
|
|
* @ec: erase count
|
|
*
|
|
* Length of the array is given by h_len field in the header.
|
|
*/
|
|
struct logfs_je_journal_ec {
|
|
__be32 ec[0];
|
|
};
|
|
|
|
SIZE_CHECK(logfs_je_journal_ec, 0);
|
|
|
|
/**
|
|
* struct logfs_je_free_segments - list of free segmetns with erase count
|
|
*/
|
|
struct logfs_je_free_segments {
|
|
__be32 segno;
|
|
__be32 ec;
|
|
};
|
|
|
|
SIZE_CHECK(logfs_je_free_segments, 8);
|
|
|
|
/**
|
|
* struct logfs_seg_alias - list of segment aliases
|
|
*/
|
|
struct logfs_seg_alias {
|
|
__be32 old_segno;
|
|
__be32 new_segno;
|
|
};
|
|
|
|
SIZE_CHECK(logfs_seg_alias, 8);
|
|
|
|
/**
|
|
* struct logfs_obj_alias - list of object aliases
|
|
*/
|
|
struct logfs_obj_alias {
|
|
__be64 ino;
|
|
__be64 bix;
|
|
__be64 val;
|
|
u8 level;
|
|
u8 pad[5];
|
|
__be16 child_no;
|
|
};
|
|
|
|
SIZE_CHECK(logfs_obj_alias, 32);
|
|
|
|
/**
|
|
* Compression types.
|
|
*
|
|
* COMPR_NONE - uncompressed
|
|
* COMPR_ZLIB - compressed with zlib
|
|
*/
|
|
enum {
|
|
COMPR_NONE = 0,
|
|
COMPR_ZLIB = 1,
|
|
};
|
|
|
|
/*
|
|
* Journal entries come in groups of 16. First group contains unique
|
|
* entries, next groups contain one entry per level
|
|
*
|
|
* JE_FIRST - smallest possible journal entry number
|
|
*
|
|
* JEG_BASE - base group, containing unique entries
|
|
* JE_COMMIT - commit entry, validates all previous entries
|
|
* JE_DYNSB - dynamic superblock, anything that ought to be in the
|
|
* superblock but cannot because it is read-write data
|
|
* JE_ANCHOR - anchor aka master inode aka inode file's inode
|
|
* JE_ERASECOUNT erasecounts for all journal segments
|
|
* JE_SPILLOUT - unused
|
|
* JE_SEG_ALIAS - aliases segments
|
|
* JE_AREA - area description
|
|
*
|
|
* JE_LAST - largest possible journal entry number
|
|
*/
|
|
enum {
|
|
JE_FIRST = 0x01,
|
|
|
|
JEG_BASE = 0x00,
|
|
JE_COMMIT = 0x02,
|
|
JE_DYNSB = 0x03,
|
|
JE_ANCHOR = 0x04,
|
|
JE_ERASECOUNT = 0x05,
|
|
JE_SPILLOUT = 0x06,
|
|
JE_OBJ_ALIAS = 0x0d,
|
|
JE_AREA = 0x0e,
|
|
|
|
JE_LAST = 0x0e,
|
|
};
|
|
|
|
#endif
|
|
|