bmap: Initial scaffolding for on-disk block map
This is pretty exploratory work, so I'm going to try to be less thorough in commit messages until the dust settles. --- New tag for gbmapdelta: LFS3_TAG_GBMAPDELTA 0x0104 v--- ---1 ---- -1rr New tags for in-bmap block types: LFS3_TAG_BMRANGE 0x033u v--- --11 --11 uuuu LFS3_TAG_BMFREE 0x0330 v--- --11 --11 ---- LFS3_TAG_BMINFLIGHT 0x0331 v--- --11 --11 ---1 LFS3_TAG_BMINUSE 0x0332 v--- --11 --11 --1- LFS3_TAG_BMBAD 0x0333 v--- --11 --11 --11 LFS3_TAG_BMERASED 0x0334 v--- --11 --11 -1-- New gstate decoding for gbmap: .---+- -+- -+- -+- -. cursor: 1 leb128 <=5 bytes | cursor | known: 1 leb128 <=5 bytes +---+- -+- -+- -+- -+ block: 1 leb128 <=5 bytes | known | trunk: 1 leb128 <=4 bytes +---+- -+- -+- -+- -+ cksum: 1 le32 4 bytes | block | total: 23 bytes +---+- -+- -+- -+- -' | trunk | +---+- -+- -+- -+ | cksum | '---+---+---+---' New bmap node revdbg string: vvv---- -111111- -11---1- -11---1- (62 62 7e v0 bb~r) bmap node New mount/format/info flags (still unsure about these): LFS3_M_BMAPMODE 0x03000000 On-disk block map mode LFS3_M_BMAPNONE 0x00000000 Don't use the bmap LFS3_M_BMAPCACHE 0x01000000 Use the bmap to cache lookahead scans LFS3_M_BMAPSLOW 0x02000000 Use the slow bmap algorithm LFS3_M_BMAPFAST 0x03000000 Use the fast bmap algorithm New gbmap wcompat flag: LFS3_WCOMPAT_GBMAP 0x00002000 Global block-map in use
This commit is contained in:
Christopher Haster
@@ -191,6 +191,15 @@ enum lfs3_type {
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#define LFS3_F_CKMETA 0x00001000 // Check metadata checksums
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#define LFS3_F_CKDATA 0x00002000 // Check metadata + data checksums
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#ifdef LFS3_BMAP
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#define LFS3_F_BMAPMODE 0x03000000 // On-disk block map mode
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#define LFS3_F_BMAPNONE 0x00000000 // Don't use the bmap
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#define LFS3_F_BMAPCACHE \
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0x01000000 // Use the bmap to cache lookahead scans
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#define LFS3_F_BMAPSLOW 0x02000000 // Use the slow bmap algorithm
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#define LFS3_F_BMAPFAST 0x03000000 // Use the fast bmap algorithm
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#endif
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#endif
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// Filesystem mount flags
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@@ -237,6 +246,16 @@ enum lfs3_type {
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#define LFS3_M_CKMETA 0x00001000 // Check metadata checksums
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#define LFS3_M_CKDATA 0x00002000 // Check metadata + data checksums
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#ifdef LFS3_BMAP
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#define LFS3_M_BMAPMODE 0x03000000 // On-disk block map mode
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#define LFS3_M_BMAPNONE 0x00000000 // Don't use the bmap
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#define LFS3_M_BMAPCACHE \
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0x01000000 // Use the bmap to cache lookahead scans
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#define LFS3_M_BMAPSLOW 0x02000000 // Use the slow bmap algorithm
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#define LFS3_M_BMAPFAST 0x03000000 // Use the fast bmap algorithm
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#endif
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// Filesystem info flags
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#define LFS3_I_RDONLY 0x00000001 // Mounted read only
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#define LFS3_I_FLUSH 0x00000040 // Mounted with LFS3_M_FLUSH
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@@ -277,9 +296,20 @@ enum lfs3_type {
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#define LFS3_I_CKMETA 0x00001000 // Metadata checksums not checked recently
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#define LFS3_I_CKDATA 0x00002000 // Data checksums not checked recently
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#ifdef LFS3_BMAP
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#define LFS3_I_BMAPMODE 0x03000000 // On-disk block map mode
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#define LFS3_I_BMAPNONE 0x00000000 // Mounted with LFS3_M_BMAPNONE
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#define LFS3_I_BMAPCACHE \
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0x01000000 // Mounted with LFS3_M_BMAPCACHE
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#define LFS3_I_BMAPSLOW 0x02000000 // Mounted with LFS3_M_BMAPSLOW
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#define LFS3_I_BMAPFAST 0x03000000 // Mounted with LFS3_M_BMAPFAST
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#endif
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// internally used flags, don't use these
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#ifdef LFS3_REVDBG
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#define LFS3_i_INMTREE 0x08000000 // Committing to mtree
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#define LFS3_i_INMODE 0x00030000
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#define LFS3_i_INMTREE 0x00010000 // Committing to mtree
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#define LFS3_i_INBMAP 0x00020000 // Committing to bmap
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#endif
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@@ -427,13 +457,20 @@ struct lfs3_cfg {
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lfs3_size_t file_cache_size;
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// Size of the lookahead buffer in bytes. A larger lookahead buffer
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// increases the number of blocks found during an allocation pass. The
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// increases the number of blocks found during an allocation scan. The
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// lookahead buffer is stored as a compact bitmap, so each byte of RAM
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// can track 8 blocks.
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#ifndef LFS3_RDONLY
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lfs3_size_t lookahead_size;
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#endif
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// Size of the treediff buffer in bytes. A larger treediff buffer speeds
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// up tree diffing in BMAPSLOW and BMAPFAST modes. The treediff buffer
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// also uses a compact bitmap, and sizes >block_count/8 have no effect.
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#if !defined(LFS3_RDONLY) && defined(LFS3_BMAP)
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lfs3_size_t treediff_size;
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#endif
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// Flags indicating what gc work to do during lfs3_gc calls.
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#ifdef LFS3_GC
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uint32_t gc_flags;
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@@ -482,6 +519,12 @@ struct lfs3_cfg {
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void *lookahead_buffer;
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#endif
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// Optional statically allocated treediff buffer. Must be treediff_size.
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// By default lfs3_malloc is used to allocate this buffer.
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#if !defined(LFS3_RDONLY) && defined(LFS3_BMAP)
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void *treediff_buffer;
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#endif
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// Optional upper limit on length of file names in bytes. No downside for
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// larger names except the size of the info struct which is controlled by
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// the LFS3_NAME_MAX define. Defaults to LFS3_NAME_MAX when zero. Stored in
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@@ -784,6 +827,8 @@ typedef struct lfs3_trv {
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lfs3_sblock_t blocks[2];
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} lfs3_trv_t;
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// littlefs global state
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// grm encoding:
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// .- -+- -+- -+- -+- -. mids: 2 leb128s <=2x5 bytes
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// ' mids ' total: <=10 bytes
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@@ -797,6 +842,26 @@ typedef struct lfs3_grm {
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lfs3_smid_t queue[2];
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} lfs3_grm_t;
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// gbmap encoding:
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// .---+- -+- -+- -+- -. cursor: 1 leb128 <=5 bytes
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// | cursor | known: 1 leb128 <=5 bytes
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// +---+- -+- -+- -+- -+ block: 1 leb128 <=5 bytes
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// | known | trunk: 1 leb128 <=4 bytes
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// +---+- -+- -+- -+- -+ cksum: 1 le32 4 bytes
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// | block | total: 23 bytes
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// +---+- -+- -+- -+- -'
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// | trunk |
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// +---+- -+- -+- -+
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// | cksum |
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// '---+---+---+---'
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#define LFS3_GBMAP_DSIZE (5+5+5+4+4)
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typedef struct lfs3_gbmap {
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lfs3_block_t cursor;
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lfs3_block_t known;
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lfs3_btree_t b;
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} lfs3_gbmap_t;
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// The littlefs filesystem type
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typedef struct lfs3 {
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@@ -857,6 +922,12 @@ typedef struct lfs3 {
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} lookahead;
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#endif
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#if !defined(LFS3_RDONLY) && !defined(LFS3_2BONLY) && defined(LFS3_BMAP)
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struct lfs3_treediff {
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uint8_t *buffer;
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} treediff;
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#endif
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#if !defined(LFS3_RDONLY) && !defined(LFS3_2BONLY)
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const lfs3_data_t *graft;
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lfs3_ssize_t graft_count;
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@@ -877,6 +948,12 @@ typedef struct lfs3 {
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// TODO can we actually get rid of grm_d when LFS3_RDONLY?
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uint8_t grm_d[LFS3_GRM_DSIZE];
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#if !defined(LFS3_RDONLY) && !defined(LFS3_2BONLY) && defined(LFS3_BMAP)
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lfs3_gbmap_t gbmap;
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uint8_t gbmap_p[LFS3_GBMAP_DSIZE];
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uint8_t gbmap_d[LFS3_GBMAP_DSIZE];
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#endif
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// optional incremental gc state
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#ifdef LFS3_GC
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struct {
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