* [PATCH 1/5] btrfs: lz4: import lz4/lz4hc C and header files
2012-06-23 8:05 [PATCH 0/5] btrfs: lz4/lz4hc compression Andrew Mahone
@ 2012-06-23 8:05 ` Andrew Mahone
2012-06-23 8:05 ` [PATCH 2/5] btrfs: lz4: add incompat flags and compression types Andrew Mahone
` (4 subsequent siblings)
5 siblings, 0 replies; 10+ messages in thread
From: Andrew Mahone @ 2012-06-23 8:05 UTC (permalink / raw)
To: linux-btrfs; +Cc: Andrew Mahone
Signed-off-by: Andrew Mahone <andrew.mahone@gmail.com>
---
fs/btrfs/lz4.c | 843 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/btrfs/lz4.h | 128 +++++++++
fs/btrfs/lz4hc.c | 685 ++++++++++++++++++++++++++++++++++++++++++++
fs/btrfs/lz4hc.h | 58 ++++
4 files changed, 1714 insertions(+)
create mode 100644 fs/btrfs/lz4.c
create mode 100644 fs/btrfs/lz4.h
create mode 100644 fs/btrfs/lz4hc.c
create mode 100644 fs/btrfs/lz4hc.h
diff --git a/fs/btrfs/lz4.c b/fs/btrfs/lz4.c
new file mode 100644
index 0000000..87d18fe
--- /dev/null
+++ b/fs/btrfs/lz4.c
@@ -0,0 +1,843 @@
+/*
+ LZ4 - Fast LZ compression algorithm
+ Copyright (C) 2011-2012, Yann Collet.
+ BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are
+ met:
+
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above
+ copyright notice, this list of conditions and the following disclaimer
+ in the documentation and/or other materials provided with the
+ distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+/*
+ * With authors permission dual licensed as BSD/GPL for linux kernel
+ *
+ * Origin: http://lz4.googlecode.com/svn/trunk
+ * Revision: 62
+ */
+
+//**************************************
+// Tuning parameters
+//**************************************
+// COMPRESSIONLEVEL :
+// Increasing this value improves compression ratio
+// Lowering this value reduces memory usage
+// Reduced memory usage typically improves speed, due to cache effect (ex : L1 32KB for Intel, L1 64KB for AMD)
+// Memory usage formula : N->2^(N+2) Bytes (examples : 12 -> 16KB ; 17 -> 512KB)
+#define COMPRESSIONLEVEL 12
+
+// NOTCOMPRESSIBLE_CONFIRMATION :
+// Decreasing this value will make the algorithm skip faster data segments considered "incompressible"
+// This may decrease compression ratio dramatically, but will be faster on incompressible data
+// Increasing this value will make the algorithm search more before declaring a segment "incompressible"
+// This could improve compression a bit, but will be slower on incompressible data
+// The default value (6) is recommended
+#define NOTCOMPRESSIBLE_CONFIRMATION 6
+
+// LZ4_COMPRESSMIN :
+// Compression function will *fail* if it is not successful at compressing input by at least LZ4_COMPRESSMIN bytes
+// Since the compression function stops working prematurely, it results in a speed gain
+// The output however is unusable. Compression function result will be zero.
+// Default : 0 = disabled
+#define LZ4_COMPRESSMIN 0
+
+// BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE :
+// This will provide a boost to performance for big endian cpu, but the resulting compressed stream will be incompatible with little-endian CPU.
+// You can set this option to 1 in situations where data will stay within closed environment
+// This option is useless on Little_Endian CPU (such as x86)
+//#define BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE 1
+
+
+
+//**************************************
+// CPU Feature Detection
+//**************************************
+// 32 or 64 bits ?
+#if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) || defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || defined(__LP64__) || defined(_LP64) ) // Detects 64 bits mode
+#define LZ4_ARCH64 1
+#else
+#define LZ4_ARCH64 0
+#endif
+
+// Little Endian or Big Endian ?
+#if (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN) || defined(_ARCH_PPC) || defined(__PPC__) || defined(__PPC) || defined(PPC) || defined(__powerpc__) || defined(__powerpc) || defined(powerpc) || ((defined(__BYTE_ORDER__)&&(__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))) )
+#define LZ4_BIG_ENDIAN 1
+#else
+// Little Endian assumed. PDP Endian and other very rare endian format are unsupported.
+#endif
+
+// Unaligned memory access is automatically enabled for "common" CPU, such as x86.
+// For others CPU, the compiler will be more cautious, and insert extra code to ensure aligned access is respected
+// If you know your target CPU supports unaligned memory access, you may want to force this option manually to improve performance
+#if defined(__ARM_FEATURE_UNALIGNED)
+#define LZ4_FORCE_UNALIGNED_ACCESS 1
+#endif
+
+// Uncomment this parameter if your target system or compiler does not support hardware bit count
+//#define LZ4_FORCE_SW_BITCOUNT
+
+
+
+//**************************************
+// Compiler Options
+//**************************************
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L // C99
+/* "restrict" is a known keyword */
+#else
+#define restrict // Disable restrict
+#endif
+
+#define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
+
+#ifdef _MSC_VER // Visual Studio
+#define inline __forceinline // Visual is not C99, but supports some kind of inline
+#include <intrin.h> // _BitScanForward
+#endif
+
+#ifdef _MSC_VER
+#define lz4_bswap16(x) _byteswap_ushort(x)
+#else
+#define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)))
+#endif
+
+#if (GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__)
+# define expect(expr,value) (__builtin_expect ((expr),(value)) )
+#else
+# define expect(expr,value) (expr)
+#endif
+
+
+//**************************************
+// Includes
+//**************************************
+#ifdef __KERNEL__
+#include <linux/string.h>
+#include <linux/bug.h>
+#define malloc(size) ({ BUG(); (void*)0; })
+#define free(ptr) ({ BUG(); (void*)0; })
+#else
+#include <stdlib.h> // for malloc
+#include <string.h> // for memset
+#include "lz4.h"
+#endif
+
+
+//**************************************
+// Basic Types
+//**************************************
+#if defined(_MSC_VER) // Visual Studio does not support 'stdint' natively
+#define BYTE unsigned __int8
+#define U16 unsigned __int16
+#define U32 unsigned __int32
+#define S32 __int32
+#define U64 unsigned __int64
+#else
+#ifdef __KERNEL__
+#include <asm/byteorder.h>
+#include <linux/types.h>
+#define BYTE u8
+#define U16 u16
+#define U32 u32
+#define S32 s32
+#define U64 u64
+
+#else
+#include <stdint.h>
+#define BYTE uint8_t
+#define U16 uint16_t
+#define U32 uint32_t
+#define S32 int32_t
+#define U64 uint64_t
+#endif // __KERNEL__
+#endif
+
+#ifndef LZ4_FORCE_UNALIGNED_ACCESS
+#pragma pack(push, 1)
+#endif
+
+typedef struct _U16_S { U16 v; } U16_S;
+typedef struct _U32_S { U32 v; } U32_S;
+typedef struct _U64_S { U64 v; } U64_S;
+
+#ifndef LZ4_FORCE_UNALIGNED_ACCESS
+#pragma pack(pop)
+#endif
+
+#define A64(x) (((U64_S *)(x))->v)
+#define A32(x) (((U32_S *)(x))->v)
+#define A16(x) (((U16_S *)(x))->v)
+
+
+//**************************************
+// Constants
+//**************************************
+#define MINMATCH 4
+
+#define HASH_LOG COMPRESSIONLEVEL
+#define HASHTABLESIZE (1 << HASH_LOG)
+#define HASH_MASK (HASHTABLESIZE - 1)
+
+#define SKIPSTRENGTH (NOTCOMPRESSIBLE_CONFIRMATION>2?NOTCOMPRESSIBLE_CONFIRMATION:2)
+#define STACKLIMIT 13
+#define HEAPMODE (HASH_LOG>STACKLIMIT) // Defines if memory is allocated into the stack (local variable), or into the heap (malloc()).
+#define COPYLENGTH 8
+#define LASTLITERALS 5
+#define MFLIMIT (COPYLENGTH+MINMATCH)
+#define MINLENGTH (MFLIMIT+1)
+
+#define MAXD_LOG 16
+#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
+
+#define ML_BITS 4
+#define ML_MASK ((1U<<ML_BITS)-1)
+#define RUN_BITS (8-ML_BITS)
+#define RUN_MASK ((1U<<RUN_BITS)-1)
+
+/*
+ * Disable on-stack context allocation for linux kernel
+ */
+#undef STACKLIMIT
+#define STACKLIMIT 0
+
+
+//**************************************
+// Architecture-specific macros
+//**************************************
+#if LZ4_ARCH64 // 64-bit
+#define STEPSIZE 8
+#define UARCH U64
+#define AARCH A64
+#define LZ4_COPYSTEP(s,d) A64(d) = A64(s); d+=8; s+=8;
+#define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d)
+#define LZ4_SECURECOPY(s,d,e) if (d<e) LZ4_WILDCOPY(s,d,e)
+#define HTYPE U32
+#define INITBASE(base) const BYTE* const base = ip
+#else // 32-bit
+#define STEPSIZE 4
+#define UARCH U32
+#define AARCH A32
+#define LZ4_COPYSTEP(s,d) A32(d) = A32(s); d+=4; s+=4;
+#define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d); LZ4_COPYSTEP(s,d);
+#define LZ4_SECURECOPY LZ4_WILDCOPY
+#define HTYPE const BYTE*
+#define INITBASE(base) const int base = 0
+#endif
+
+#if (defined(LZ4_BIG_ENDIAN) && !defined(BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE))
+#define LZ4_READ_LITTLEENDIAN_16(d,s,p) { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }
+#define LZ4_WRITE_LITTLEENDIAN_16(p,i) { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p+=2; }
+#else // Little Endian
+#define LZ4_READ_LITTLEENDIAN_16(d,s,p) { d = (s) - A16(p); }
+#define LZ4_WRITE_LITTLEENDIAN_16(p,v) { A16(p) = v; p+=2; }
+#endif
+
+
+//**************************************
+// Local structures
+//**************************************
+struct refTables
+{
+ HTYPE hashTable[HASHTABLESIZE];
+};
+
+
+//**************************************
+// Macros
+//**************************************
+#define LZ4_HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASH_LOG))
+#define LZ4_HASH_VALUE(p) LZ4_HASH_FUNCTION(A32(p))
+#define LZ4_WILDCOPY(s,d,e) do { LZ4_COPYPACKET(s,d) } while (d<e);
+#define LZ4_BLINDCOPY(s,d,l) { BYTE* e=(d)+l; LZ4_WILDCOPY(s,d,e); d=e; }
+
+
+//****************************
+// Private functions
+//****************************
+#if LZ4_ARCH64
+
+inline static int LZ4_NbCommonBytes (register U64 val)
+{
+#if defined(LZ4_BIG_ENDIAN)
+ #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ unsigned long r = 0;
+ _BitScanReverse64( &r, val );
+ return (int)(r>>3);
+ #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ return (__builtin_clzll(val) >> 3);
+ #else
+ int r;
+ if (!(val>>32)) { r=4; } else { r=0; val>>=32; }
+ if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
+ r += (!val);
+ return r;
+ #endif
+#else
+ #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ unsigned long r = 0;
+ _BitScanForward64( &r, val );
+ return (int)(r>>3);
+ #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ return (__builtin_ctzll(val) >> 3);
+ #else
+ static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };
+ return DeBruijnBytePos[((U64)((val & -val) * 0x0218A392CDABBD3F)) >> 58];
+ #endif
+#endif
+}
+
+#else
+
+inline static int LZ4_NbCommonBytes (register U32 val)
+{
+#if defined(LZ4_BIG_ENDIAN)
+ #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ unsigned long r = 0;
+ _BitScanReverse( &r, val );
+ return (int)(r>>3);
+ #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ return (__builtin_clz(val) >> 3);
+ #else
+ int r;
+ if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
+ r += (!val);
+ return r;
+ #endif
+#else
+ #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ unsigned long r = 0;
+ _BitScanForward( &r, val );
+ return (int)(r>>3);
+ #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ return (__builtin_ctz(val) >> 3);
+ #else
+ static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
+ return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
+ #endif
+#endif
+}
+
+#endif
+
+
+//****************************
+// Public functions
+//****************************
+
+int LZ4_compressBound(int isize)
+{
+ return (isize + (isize/255) + 16);
+}
+
+
+
+//******************************
+// Compression functions
+//******************************
+
+int LZ4_compressCtx(void** ctx,
+ const char* source,
+ char* dest,
+ int isize)
+{
+#if HEAPMODE
+ struct refTables *srt = (struct refTables *) (*ctx);
+ HTYPE* HashTable;
+#else
+ HTYPE HashTable[HASHTABLESIZE] = {0};
+#endif
+
+ const BYTE* ip = (BYTE*) source;
+ INITBASE(base);
+ const BYTE* anchor = ip;
+ const BYTE* const iend = ip + isize;
+ const BYTE* const mflimit = iend - MFLIMIT;
+#define matchlimit (iend - LASTLITERALS)
+
+ BYTE* op = (BYTE*) dest;
+
+ int len, length;
+ const int skipStrength = SKIPSTRENGTH;
+ U32 forwardH;
+
+
+ // Init
+ if (isize<MINLENGTH) goto _last_literals;
+#if HEAPMODE
+ if (*ctx == NULL)
+ {
+ srt = (struct refTables *) malloc ( sizeof(struct refTables) );
+ *ctx = (void*) srt;
+ }
+ HashTable = (HTYPE*)(srt->hashTable);
+ memset((void*)HashTable, 0, sizeof(srt->hashTable));
+#else
+ (void) ctx;
+#endif
+
+
+ // First Byte
+ HashTable[LZ4_HASH_VALUE(ip)] = ip - base;
+ ip++; forwardH = LZ4_HASH_VALUE(ip);
+
+ // Main Loop
+ for ( ; ; )
+ {
+ int findMatchAttempts = (1U << skipStrength) + 3;
+ const BYTE* forwardIp = ip;
+ const BYTE* ref;
+ BYTE* token;
+
+ // Find a match
+ do {
+ U32 h = forwardH;
+ int step = findMatchAttempts++ >> skipStrength;
+ ip = forwardIp;
+ forwardIp = ip + step;
+
+ if (unlikely(forwardIp > mflimit)) { goto _last_literals; }
+
+ forwardH = LZ4_HASH_VALUE(forwardIp);
+ ref = base + HashTable[h];
+ HashTable[h] = ip - base;
+
+ } while ((ref < ip - MAX_DISTANCE) || (A32(ref) != A32(ip)));
+
+ // Catch up
+ while ((ip>anchor) && (ref>(BYTE*)source) && unlikely(ip[-1]==ref[-1])) { ip--; ref--; }
+
+ // Encode Literal length
+ length = ip - anchor;
+ token = op++;
+ if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *op++ = 255; *op++ = (BYTE)len; }
+ else *token = (length<<ML_BITS);
+
+ // Copy Literals
+ LZ4_BLINDCOPY(anchor, op, length);
+
+_next_match:
+ // Encode Offset
+ LZ4_WRITE_LITTLEENDIAN_16(op,ip-ref);
+
+ // Start Counting
+ ip+=MINMATCH; ref+=MINMATCH; // MinMatch verified
+ anchor = ip;
+ while (likely(ip<matchlimit-(STEPSIZE-1)))
+ {
+ UARCH diff = AARCH(ref) ^ AARCH(ip);
+ if (!diff) { ip+=STEPSIZE; ref+=STEPSIZE; continue; }
+ ip += LZ4_NbCommonBytes(diff);
+ goto _endCount;
+ }
+ if (LZ4_ARCH64) if ((ip<(matchlimit-3)) && (A32(ref) == A32(ip))) { ip+=4; ref+=4; }
+ if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; }
+ if ((ip<matchlimit) && (*ref == *ip)) ip++;
+_endCount:
+
+ // Encode MatchLength
+ len = (ip - anchor);
+ if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *op++ = 255; *op++ = 255; } if (len > 254) { len-=255; *op++ = 255; } *op++ = (BYTE)len; }
+ else *token += len;
+
+ // Test end of chunk
+ if (ip > mflimit) { anchor = ip; break; }
+
+ // Fill table
+ HashTable[LZ4_HASH_VALUE(ip-2)] = ip - 2 - base;
+
+ // Test next position
+ ref = base + HashTable[LZ4_HASH_VALUE(ip)];
+ HashTable[LZ4_HASH_VALUE(ip)] = ip - base;
+ if ((ref > ip - (MAX_DISTANCE + 1)) && (A32(ref) == A32(ip))) { token = op++; *token=0; goto _next_match; }
+
+ // Prepare next loop
+ anchor = ip++;
+ forwardH = LZ4_HASH_VALUE(ip);
+ }
+
+_last_literals:
+ // Encode Last Literals
+ {
+ int lastRun = iend - anchor;
+ if ((LZ4_COMPRESSMIN>0) && (((op - (BYTE*)dest) + lastRun + 1 + ((lastRun-15)/255)) > isize - LZ4_COMPRESSMIN)) return 0;
+ if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; }
+ else *op++ = (lastRun<<ML_BITS);
+ memcpy(op, anchor, iend - anchor);
+ op += iend-anchor;
+ }
+
+ // End
+ return (int) (((char*)op)-dest);
+}
+
+
+
+// Note : this function is valid only if isize < LZ4_64KLIMIT
+#define LZ4_64KLIMIT ((1<<16) + (MFLIMIT-1))
+#define HASHLOG64K (HASH_LOG+1)
+#define HASH64KTABLESIZE (1U<<HASHLOG64K)
+#define LZ4_HASH64K_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASHLOG64K))
+#define LZ4_HASH64K_VALUE(p) LZ4_HASH64K_FUNCTION(A32(p))
+int LZ4_compress64kCtx(void** ctx,
+ const char* source,
+ char* dest,
+ int isize)
+{
+#if HEAPMODE
+ struct refTables *srt = (struct refTables *) (*ctx);
+ U16* HashTable;
+#else
+ U16 HashTable[HASH64KTABLESIZE] = {0};
+#endif
+
+ const BYTE* ip = (BYTE*) source;
+ const BYTE* anchor = ip;
+ const BYTE* const base = ip;
+ const BYTE* const iend = ip + isize;
+ const BYTE* const mflimit = iend - MFLIMIT;
+#define matchlimit (iend - LASTLITERALS)
+
+ BYTE* op = (BYTE*) dest;
+
+ int len, length;
+ const int skipStrength = SKIPSTRENGTH;
+ U32 forwardH;
+
+
+ // Init
+ if (isize<MINLENGTH) goto _last_literals;
+#if HEAPMODE
+ if (*ctx == NULL)
+ {
+ srt = (struct refTables *) malloc ( sizeof(struct refTables) );
+ *ctx = (void*) srt;
+ }
+ HashTable = (U16*)(srt->hashTable);
+ memset((void*)HashTable, 0, sizeof(srt->hashTable));
+#else
+ (void) ctx;
+#endif
+
+
+ // First Byte
+ ip++; forwardH = LZ4_HASH64K_VALUE(ip);
+
+ // Main Loop
+ for ( ; ; )
+ {
+ int findMatchAttempts = (1U << skipStrength) + 3;
+ const BYTE* forwardIp = ip;
+ const BYTE* ref;
+ BYTE* token;
+
+ // Find a match
+ do {
+ U32 h = forwardH;
+ int step = findMatchAttempts++ >> skipStrength;
+ ip = forwardIp;
+ forwardIp = ip + step;
+
+ if (forwardIp > mflimit) { goto _last_literals; }
+
+ forwardH = LZ4_HASH64K_VALUE(forwardIp);
+ ref = base + HashTable[h];
+ HashTable[h] = ip - base;
+
+ } while (A32(ref) != A32(ip));
+
+ // Catch up
+ while ((ip>anchor) && (ref>(BYTE*)source) && (ip[-1]==ref[-1])) { ip--; ref--; }
+
+ // Encode Literal length
+ length = ip - anchor;
+ token = op++;
+ if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *op++ = 255; *op++ = (BYTE)len; }
+ else *token = (length<<ML_BITS);
+
+ // Copy Literals
+ LZ4_BLINDCOPY(anchor, op, length);
+
+_next_match:
+ // Encode Offset
+ LZ4_WRITE_LITTLEENDIAN_16(op,ip-ref);
+
+ // Start Counting
+ ip+=MINMATCH; ref+=MINMATCH; // MinMatch verified
+ anchor = ip;
+ while (ip<matchlimit-(STEPSIZE-1))
+ {
+ UARCH diff = AARCH(ref) ^ AARCH(ip);
+ if (!diff) { ip+=STEPSIZE; ref+=STEPSIZE; continue; }
+ ip += LZ4_NbCommonBytes(diff);
+ goto _endCount;
+ }
+ if (LZ4_ARCH64) if ((ip<(matchlimit-3)) && (A32(ref) == A32(ip))) { ip+=4; ref+=4; }
+ if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; }
+ if ((ip<matchlimit) && (*ref == *ip)) ip++;
+_endCount:
+
+ // Encode MatchLength
+ len = (ip - anchor);
+ if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *op++ = 255; *op++ = 255; } if (len > 254) { len-=255; *op++ = 255; } *op++ = (BYTE)len; }
+ else *token += len;
+
+ // Test end of chunk
+ if (ip > mflimit) { anchor = ip; break; }
+
+ // Fill table
+ HashTable[LZ4_HASH64K_VALUE(ip-2)] = ip - 2 - base;
+
+ // Test next position
+ ref = base + HashTable[LZ4_HASH64K_VALUE(ip)];
+ HashTable[LZ4_HASH64K_VALUE(ip)] = ip - base;
+ if (A32(ref) == A32(ip)) { token = op++; *token=0; goto _next_match; }
+
+ // Prepare next loop
+ anchor = ip++;
+ forwardH = LZ4_HASH64K_VALUE(ip);
+ }
+
+_last_literals:
+ // Encode Last Literals
+ {
+ int lastRun = iend - anchor;
+ if ((LZ4_COMPRESSMIN>0) && (((op - (BYTE*)dest) + lastRun + 1 + ((lastRun-15)/255)) > isize - LZ4_COMPRESSMIN)) return 0;
+ if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; }
+ else *op++ = (lastRun<<ML_BITS);
+ memcpy(op, anchor, iend - anchor);
+ op += iend-anchor;
+ }
+
+ // End
+ return (int) (((char*)op)-dest);
+}
+
+
+
+int LZ4_compress(const char* source,
+ char* dest,
+ int isize)
+{
+#if HEAPMODE
+ void* ctx = malloc(sizeof(struct refTables));
+ int result;
+ if (isize < LZ4_64KLIMIT)
+ result = LZ4_compress64kCtx(&ctx, source, dest, isize);
+ else result = LZ4_compressCtx(&ctx, source, dest, isize);
+ free(ctx);
+ return result;
+#else
+ if (isize < (int)LZ4_64KLIMIT) return LZ4_compress64kCtx(NULL, source, dest, isize);
+ return LZ4_compressCtx(NULL, source, dest, isize);
+#endif
+}
+
+
+
+
+//****************************
+// Decompression functions
+//****************************
+
+// Note : The decoding functions LZ4_uncompress() and LZ4_uncompress_unknownOutputSize()
+// are safe against "buffer overflow" attack type.
+// They will never write nor read outside of the provided output buffers.
+// LZ4_uncompress_unknownOutputSize() also insures that it will never read outside of the input buffer.
+// A corrupted input will produce an error result, a negative int, indicating the position of the error within input stream.
+
+int LZ4_uncompress(const char* source,
+ char* dest,
+ int osize)
+{
+ // Local Variables
+ const BYTE* restrict ip = (const BYTE*) source;
+ const BYTE* restrict ref;
+
+ BYTE* restrict op = (BYTE*) dest;
+ BYTE* const oend = op + osize;
+ BYTE* cpy;
+
+ BYTE token;
+
+ int len, length;
+ size_t dec[] ={0, 3, 2, 3, 0, 0, 0, 0};
+
+
+ // Main Loop
+ while (1)
+ {
+ // get runlength
+ token = *ip++;
+ if ((length=(token>>ML_BITS)) == RUN_MASK) { for (;(len=*ip++)==255;length+=255){} length += len; }
+
+ // copy literals
+ cpy = op+length;
+ if (unlikely(cpy>oend-COPYLENGTH))
+ {
+ if (cpy > oend) goto _output_error;
+ memcpy(op, ip, length);
+ ip += length;
+ break; // Necessarily EOF
+ }
+ LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy;
+
+ // get offset
+ LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;
+ if (ref < (BYTE* const)dest) goto _output_error;
+
+ // get matchlength
+ if ((length=(token&ML_MASK)) == ML_MASK) { for (;*ip==255;length+=255) {ip++;} length += *ip++; }
+
+ // copy repeated sequence
+ if (unlikely(op-ref<STEPSIZE))
+ {
+#if LZ4_ARCH64
+ size_t dec2table[]={0, 0, 0, -1, 0, 1, 2, 3};
+ size_t dec2 = dec2table[op-ref];
+#else
+ const int dec2 = 0;
+#endif
+ *op++ = *ref++;
+ *op++ = *ref++;
+ *op++ = *ref++;
+ *op++ = *ref++;
+ ref -= dec[op-ref];
+ A32(op)=A32(ref); op += STEPSIZE-4;
+ ref -= dec2;
+ } else { LZ4_COPYSTEP(ref,op); }
+ cpy = op + length - (STEPSIZE-4);
+ if (cpy>oend-COPYLENGTH)
+ {
+ if (cpy > oend) goto _output_error;
+ LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH));
+ while(op<cpy) *op++=*ref++;
+ op=cpy;
+ if (op == oend) break; // Check EOF (should never happen, since last 5 bytes are supposed to be literals)
+ continue;
+ }
+ LZ4_SECURECOPY(ref, op, cpy);
+ op=cpy; // correction
+ }
+
+ // end of decoding
+ return (int) (((char*)ip)-source);
+
+ // write overflow error detected
+_output_error:
+ return (int) (-(((char*)ip)-source));
+}
+
+
+int LZ4_uncompress_unknownOutputSize(
+ const char* source,
+ char* dest,
+ int isize,
+ int maxOutputSize)
+{
+ // Local Variables
+ const BYTE* restrict ip = (const BYTE*) source;
+ const BYTE* const iend = ip + isize;
+ const BYTE* restrict ref;
+
+ BYTE* restrict op = (BYTE*) dest;
+ BYTE* const oend = op + maxOutputSize;
+ BYTE* cpy;
+
+ size_t dec[] ={0, 3, 2, 3, 0, 0, 0, 0};
+
+
+ // Main Loop
+ while (ip<iend)
+ {
+ BYTE token;
+ int length;
+
+ // get runlength
+ token = *ip++;
+ if ((length=(token>>ML_BITS)) == RUN_MASK) { int s=255; while ((ip<iend) && (s==255)) { s=*ip++; length += s; } }
+
+ // copy literals
+ cpy = op+length;
+ if ((cpy>oend-COPYLENGTH) || (ip+length>iend-COPYLENGTH))
+ {
+ if (cpy > oend) goto _output_error;
+ if (ip+length > iend) goto _output_error;
+ memcpy(op, ip, length);
+ op += length;
+ ip += length;
+ if (ip<iend) goto _output_error;
+ break; // Necessarily EOF, due to parsing restrictions
+ }
+ LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy;
+
+ // get offset
+ LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;
+ if (ref < (BYTE* const)dest) goto _output_error;
+
+ // get matchlength
+ if ((length=(token&ML_MASK)) == ML_MASK) { while (ip<iend) { int s = *ip++; length +=s; if (s==255) continue; break; } }
+
+ // copy repeated sequence
+ if (unlikely(op-ref<STEPSIZE))
+ {
+#if LZ4_ARCH64
+ size_t dec2table[]={0, 0, 0, -1, 0, 1, 2, 3};
+ size_t dec2 = dec2table[op-ref];
+#else
+ const int dec2 = 0;
+#endif
+ *op++ = *ref++;
+ *op++ = *ref++;
+ *op++ = *ref++;
+ *op++ = *ref++;
+ ref -= dec[op-ref];
+ A32(op)=A32(ref); op += STEPSIZE-4;
+ ref -= dec2;
+ } else { LZ4_COPYSTEP(ref,op); }
+ cpy = op + length - (STEPSIZE-4);
+ if (cpy>oend-COPYLENGTH)
+ {
+ if (cpy > oend) goto _output_error;
+ LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH));
+ while(op<cpy) *op++=*ref++;
+ op=cpy;
+ if (op == oend) break; // Check EOF (should never happen, since last 5 bytes are supposed to be literals)
+ continue;
+ }
+ LZ4_SECURECOPY(ref, op, cpy);
+ op=cpy; // correction
+ }
+
+ // end of decoding
+ return (int) (((char*)op)-dest);
+
+ // write overflow error detected
+_output_error:
+ return (int) (-(((char*)ip)-source));
+}
+
+int LZ4_context_size(void)
+{
+ return sizeof(struct refTables);
+}
+int LZ4_context64k_size(void)
+{
+ return sizeof(struct refTables);
+}
+
diff --git a/fs/btrfs/lz4.h b/fs/btrfs/lz4.h
new file mode 100644
index 0000000..dcd8f44
--- /dev/null
+++ b/fs/btrfs/lz4.h
@@ -0,0 +1,128 @@
+/*
+ LZ4 - Fast LZ compression algorithm
+ Header File
+ Copyright (C) 2011, Yann Collet.
+ BSD License
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are
+ met:
+
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above
+ copyright notice, this list of conditions and the following disclaimer
+ in the documentation and/or other materials provided with the
+ distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/*
+ * With authors permission dual licensed as BSD/GPL for linux kernel
+ *
+ * Origin: http://lz4.googlecode.com/svn/trunk
+ * Revision: 62
+ */
+#pragma once
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+
+//****************************
+// Simple Functions
+//****************************
+
+int LZ4_compress (const char* source, char* dest, int isize);
+int LZ4_uncompress (const char* source, char* dest, int osize);
+
+/*
+LZ4_compress() :
+ isize : is the input size. Max supported value is ~1.9GB
+ return : the number of bytes written in buffer dest
+ or 0 if the compression fails (if LZ4_COMPRESSMIN is set)
+ note : destination buffer must be already allocated.
+ destination buffer must be sized to handle worst cases situations (input data not compressible)
+ worst case size evaluation is provided by function LZ4_compressBound()
+
+LZ4_uncompress() :
+ osize : is the output size, therefore the original size
+ return : the number of bytes read in the source buffer
+ If the source stream is malformed, the function will stop decoding and return a negative result, indicating the byte position of the faulty instruction
+ This function never writes beyond dest + osize, and is therefore protected against malicious data packets
+ note : destination buffer must be already allocated
+*/
+
+
+//****************************
+// Advanced Functions
+//****************************
+
+int LZ4_compressBound(int isize);
+
+/*
+LZ4_compressBound() :
+ Provides the maximum size that LZ4 may output in a "worst case" scenario (input data not compressible)
+ primarily useful for memory allocation of output buffer.
+
+ isize : is the input size. Max supported value is ~1.9GB
+ return : maximum output size in a "worst case" scenario
+ note : this function is limited by "int" range (2^31-1)
+*/
+
+
+int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize);
+
+/*
+LZ4_uncompress_unknownOutputSize() :
+ isize : is the input size, therefore the compressed size
+ maxOutputSize : is the size of the destination buffer (which must be already allocated)
+ return : the number of bytes decoded in the destination buffer (necessarily <= maxOutputSize)
+ If the source stream is malformed, the function will stop decoding and return a negative result, indicating the byte position of the faulty instruction
+ This function never writes beyond dest + maxOutputSize, and is therefore protected against malicious data packets
+ note : This version is slightly slower than LZ4_uncompress()
+*/
+
+
+int LZ4_compressCtx(void** ctx, const char* source, char* dest, int isize);
+
+/*
+LZ4_compressCtx() :
+ This function explicitly handles the CTX memory structure.
+ It avoids allocating/deallocating memory between each call, improving performance when malloc is heavily invoked.
+ This function is only useful when memory is allocated into the heap (HASH_LOG value beyond STACK_LIMIT)
+ Performance difference will be noticeable only when repetitively calling the compression function over many small segments.
+ Note : by default, memory is allocated into the stack, therefore "malloc" is not invoked.
+LZ4_compress64kCtx() :
+ Same as LZ4_compressCtx(), but specific to small inputs (<64KB).
+ isize *Must* be <64KB, otherwise the output will be corrupted.
+
+ On first call : provide a *ctx=NULL; It will be automatically allocated.
+ On next calls : reuse the same ctx pointer.
+ Use different pointers for different threads when doing multi-threading.
+
+*/
+
+int LZ4_compress64kCtx(void** ctx,
+ const char* source,
+ char* dest,
+ int isize);
+
+int LZ4_context_size(void);
+int LZ4_context64k_size(void);
+
+#if defined (__cplusplus)
+}
+#endif
diff --git a/fs/btrfs/lz4hc.c b/fs/btrfs/lz4hc.c
new file mode 100644
index 0000000..f69c77a
--- /dev/null
+++ b/fs/btrfs/lz4hc.c
@@ -0,0 +1,685 @@
+/*
+ LZ4 HC - High Compression Mode of LZ4
+ Copyright (C) 2011-2012, Yann Collet.
+ L-GPL v3 License
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License along
+ with this program; if not, see <http://www.gnu.org/licenses/>,
+ or write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+ You can contact the author at :
+ - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
+ - LZ4-HC source repository : http://code.google.com/p/lz4hc/
+*/
+
+
+
+//**************************************
+// CPU Feature Detection
+//**************************************
+// 32 or 64 bits ?
+#if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) || defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || defined(__LP64__) || defined(_LP64) ) // Detects 64 bits mode
+#define LZ4_ARCH64 1
+#else
+#define LZ4_ARCH64 0
+#endif
+
+// Little Endian or Big Endian ?
+#if (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN) || defined(_ARCH_PPC) || defined(__PPC__) || defined(__PPC) || defined(PPC) || defined(__powerpc__) || defined(__powerpc) || defined(powerpc) || ((defined(__BYTE_ORDER__)&&(__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))) )
+#define LZ4_BIG_ENDIAN 1
+#else
+// Little Endian assumed. PDP Endian and other very rare endian format are unsupported.
+#endif
+
+// Unaligned memory access is automatically enabled for "common" CPU, such as x86.
+// For others CPU, the compiler will be more cautious, and insert extra code to ensure aligned access is respected
+// If you know your target CPU supports unaligned memory access, you may want to force this option manually to improve performance
+#if defined(__ARM_FEATURE_UNALIGNED)
+#define LZ4_FORCE_UNALIGNED_ACCESS 1
+#endif
+
+
+//**************************************
+// Compiler Options
+//**************************************
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L // C99
+ /* "restrict" is a known keyword */
+#else
+#define restrict // Disable restrict
+#endif
+
+#ifdef _MSC_VER
+#define inline __forceinline // Visual is not C99, but supports some kind of inline
+#endif
+
+#ifdef _MSC_VER // Visual Studio
+#define bswap16(x) _byteswap_ushort(x)
+#else
+#define bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)))
+#endif
+
+
+//**************************************
+// Includes
+//**************************************
+#ifdef __KERNEL__
+#include <linux/string.h>
+#include <linux/bug.h>
+#define calloc(x,size) ({ BUG(); (void*)0; })
+#define malloc(size) ({ BUG(); (void*)0; })
+#define free(ptr) ({ BUG(); (void*)0; })
+#else
+#include <stdlib.h> // calloc, free
+#include <string.h> // memset, memcpy
+#include "lz4hc.h"
+#endif
+
+#define ALLOCATOR(s) calloc(1,s)
+#define FREEMEM free
+#define MEM_INIT memset
+
+
+//**************************************
+// Basic Types
+//**************************************
+#if defined(_MSC_VER) // Visual Studio does not support 'stdint' natively
+#define BYTE unsigned __int8
+#define U16 unsigned __int16
+#define U32 unsigned __int32
+#define S32 __int32
+#define U64 unsigned __int64
+#else
+#ifdef __KERNEL__
+#include <asm/byteorder.h>
+#include <linux/types.h>
+#define BYTE u8
+#define U16 u16
+#define U32 u32
+#define S32 s32
+#define U64 u64
+
+#else
+#include <stdint.h>
+#define BYTE uint8_t
+#define U16 uint16_t
+#define U32 uint32_t
+#define S32 int32_t
+#define U64 uint64_t
+#endif // __KERNEL__
+#endif
+
+#ifndef LZ4_FORCE_UNALIGNED_ACCESS
+#pragma pack(push, 1)
+#endif
+
+typedef struct _U16_S { U16 v; } U16_S;
+typedef struct _U32_S { U32 v; } U32_S;
+typedef struct _U64_S { U64 v; } U64_S;
+
+#ifndef LZ4_FORCE_UNALIGNED_ACCESS
+#pragma pack(pop)
+#endif
+
+#define A64(x) (((U64_S *)(x))->v)
+#define A32(x) (((U32_S *)(x))->v)
+#define A16(x) (((U16_S *)(x))->v)
+
+
+//**************************************
+// Constants
+//**************************************
+#define MINMATCH 4
+
+#define DICTIONARY_LOGSIZE 16
+#define MAXD (1<<DICTIONARY_LOGSIZE)
+#define MAXD_MASK ((U32)(MAXD - 1))
+#define MAX_DISTANCE (MAXD - 1)
+
+#define HASH_LOG (DICTIONARY_LOGSIZE-1)
+#define HASHTABLESIZE (1 << HASH_LOG)
+#define HASH_MASK (HASHTABLESIZE - 1)
+
+#define MAX_NB_ATTEMPTS 256
+
+#define ML_BITS 4
+#define ML_MASK (size_t)((1U<<ML_BITS)-1)
+#define RUN_BITS (8-ML_BITS)
+#define RUN_MASK ((1U<<RUN_BITS)-1)
+
+#define COPYLENGTH 8
+#define LASTLITERALS 5
+#define MFLIMIT (COPYLENGTH+MINMATCH)
+#define MINLENGTH (MFLIMIT+1)
+#define OPTIMAL_ML (int)((ML_MASK-1)+MINMATCH)
+
+
+//**************************************
+// Architecture-specific macros
+//**************************************
+#if LZ4_ARCH64 // 64-bit
+#define STEPSIZE 8
+#define LZ4_COPYSTEP(s,d) A64(d) = A64(s); d+=8; s+=8;
+#define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d)
+#define UARCH U64
+#define AARCH A64
+#define HTYPE U32
+#define INITBASE(b,s) const BYTE* const b = s
+#else // 32-bit
+#define STEPSIZE 4
+#define LZ4_COPYSTEP(s,d) A32(d) = A32(s); d+=4; s+=4;
+#define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d); LZ4_COPYSTEP(s,d);
+#define UARCH U32
+#define AARCH A32
+#define HTYPE const BYTE*
+#define INITBASE(b,s) const int b = 0
+#endif
+
+#if defined(LZ4_BIG_ENDIAN)
+#define LZ4_READ_LITTLEENDIAN_16(d,s,p) { U16 v = A16(p); v = bswap16(v); d = (s) - v; }
+#define LZ4_WRITE_LITTLEENDIAN_16(p,i) { U16 v = (U16)(i); v = bswap16(v); A16(p) = v; p+=2; }
+#else // Little Endian
+#define LZ4_READ_LITTLEENDIAN_16(d,s,p) { d = (s) - A16(p); }
+#define LZ4_WRITE_LITTLEENDIAN_16(p,v) { A16(p) = v; p+=2; }
+#endif
+
+
+//************************************************************
+// Local Types
+//************************************************************
+typedef struct
+{
+ const BYTE* base;
+ HTYPE hashTable[HASHTABLESIZE];
+ U16 chainTable[MAXD];
+ const BYTE* nextToUpdate;
+} LZ4HC_Data_Structure;
+
+
+//**************************************
+// Macros
+//**************************************
+#define LZ4_WILDCOPY(s,d,e) do { LZ4_COPYPACKET(s,d) } while (d<e);
+#define LZ4_BLINDCOPY(s,d,l) { BYTE* e=d+l; LZ4_WILDCOPY(s,d,e); d=e; }
+#define HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASH_LOG))
+#define HASH_VALUE(p) HASH_FUNCTION(*(U32*)(p))
+#define HASH_POINTER(p) (HashTable[HASH_VALUE(p)] + base)
+#define DELTANEXT(p) chainTable[(size_t)(p) & MAXD_MASK]
+#define GETNEXT(p) ((p) - (size_t)DELTANEXT(p))
+#define ADD_HASH(p) { size_t delta = (p) - HASH_POINTER(p); if (delta>MAX_DISTANCE) delta = MAX_DISTANCE; DELTANEXT(p) = (U16)delta; HashTable[HASH_VALUE(p)] = (p) - base; }
+
+
+//**************************************
+// Private functions
+//**************************************
+#if LZ4_ARCH64
+
+inline static int LZ4_NbCommonBytes (register U64 val)
+{
+#if defined(LZ4_BIG_ENDIAN)
+ #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ unsigned long r = 0;
+ _BitScanReverse64( &r, val );
+ return (int)(r>>3);
+ #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ return (__builtin_clzll(val) >> 3);
+ #else
+ int r;
+ if (!(val>>32)) { r=4; } else { r=0; val>>=32; }
+ if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
+ r += (!val);
+ return r;
+ #endif
+#else
+ #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ unsigned long r = 0;
+ _BitScanForward64( &r, val );
+ return (int)(r>>3);
+ #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ return (__builtin_ctzll(val) >> 3);
+ #else
+ static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };
+ return DeBruijnBytePos[((U64)((val & -val) * 0x0218A392CDABBD3F)) >> 58];
+ #endif
+#endif
+}
+
+#else
+
+inline static int LZ4_NbCommonBytes (register U32 val)
+{
+#if defined(LZ4_BIG_ENDIAN)
+ #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ unsigned long r = 0;
+ _BitScanReverse( &r, val );
+ return (int)(r>>3);
+ #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ return (__builtin_clz(val) >> 3);
+ #else
+ int r;
+ if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
+ r += (!val);
+ return r;
+ #endif
+#else
+ #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ unsigned long r = 0;
+ _BitScanForward( &r, val );
+ return (int)(r>>3);
+ #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
+ return (__builtin_ctz(val) >> 3);
+ #else
+ static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
+ return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
+ #endif
+#endif
+}
+
+#endif
+
+
+inline static int LZ4HC_Init (LZ4HC_Data_Structure* hc4, const BYTE* base)
+{
+ MEM_INIT((void*)hc4->hashTable, 0, sizeof(hc4->hashTable));
+ MEM_INIT(hc4->chainTable, 0xFF, sizeof(hc4->chainTable));
+ hc4->nextToUpdate = base + LZ4_ARCH64;
+ hc4->base = base;
+ return 1;
+}
+
+
+inline static void* LZ4HC_Create (const BYTE* base)
+{
+ void* hc4 = ALLOCATOR(sizeof(LZ4HC_Data_Structure));
+
+ LZ4HC_Init (hc4, base);
+ return hc4;
+}
+
+
+inline static int LZ4HC_Free (void** LZ4HC_Data)
+{
+ FREEMEM(*LZ4HC_Data);
+ *LZ4HC_Data = NULL;
+ return (1);
+}
+
+
+inline static void LZ4HC_Insert (LZ4HC_Data_Structure* hc4, const BYTE* ip)
+{
+ U16* chainTable = hc4->chainTable;
+ HTYPE* HashTable = hc4->hashTable;
+ INITBASE(base,hc4->base);
+
+ while(hc4->nextToUpdate < ip)
+ {
+ ADD_HASH(hc4->nextToUpdate);
+ hc4->nextToUpdate++;
+ }
+}
+
+
+inline static int LZ4HC_InsertAndFindBestMatch (LZ4HC_Data_Structure* hc4, const BYTE* ip, const BYTE* const matchlimit, const BYTE** matchpos)
+{
+ U16* const chainTable = hc4->chainTable;
+ HTYPE* const HashTable = hc4->hashTable;
+ const BYTE* ref;
+ INITBASE(base,hc4->base);
+ int nbAttempts=MAX_NB_ATTEMPTS;
+ int ml=0;
+
+ // HC4 match finder
+ LZ4HC_Insert(hc4, ip);
+ ref = HASH_POINTER(ip);
+ while ((ref > (ip-MAX_DISTANCE)) && (nbAttempts))
+ {
+ nbAttempts--;
+ if (*(ref+ml) == *(ip+ml))
+ if (*(U32*)ref == *(U32*)ip)
+ {
+ const BYTE* reft = ref+MINMATCH;
+ const BYTE* ipt = ip+MINMATCH;
+
+ while (ipt<matchlimit-(STEPSIZE-1))
+ {
+ UARCH diff = AARCH(reft) ^ AARCH(ipt);
+ if (!diff) { ipt+=STEPSIZE; reft+=STEPSIZE; continue; }
+ ipt += LZ4_NbCommonBytes(diff);
+ goto _endCount;
+ }
+ if (LZ4_ARCH64) if ((ipt<(matchlimit-3)) && (A32(reft) == A32(ipt))) { ipt+=4; reft+=4; }
+ if ((ipt<(matchlimit-1)) && (A16(reft) == A16(ipt))) { ipt+=2; reft+=2; }
+ if ((ipt<matchlimit) && (*reft == *ipt)) ipt++;
+_endCount:
+
+ if (ipt-ip > ml) { ml = ipt-ip; *matchpos = ref; }
+ }
+ ref = GETNEXT(ref);
+ }
+
+ return ml;
+}
+
+
+inline static int LZ4HC_InsertAndGetWiderMatch (LZ4HC_Data_Structure* hc4, const BYTE* ip, const BYTE* startLimit, const BYTE* matchlimit, int longest, const BYTE** matchpos, const BYTE** startpos)
+{
+ U16* const chainTable = hc4->chainTable;
+ HTYPE* const HashTable = hc4->hashTable;
+ INITBASE(base,hc4->base);
+ const BYTE* ref;
+ int nbAttempts = MAX_NB_ATTEMPTS;
+ int delta = ip-startLimit;
+
+ // First Match
+ LZ4HC_Insert(hc4, ip);
+ ref = HASH_POINTER(ip);
+
+ while ((ref > ip-MAX_DISTANCE) && (ref >= hc4->base) && (nbAttempts))
+ {
+ nbAttempts--;
+ if (*(startLimit + longest) == *(ref - delta + longest))
+ if (*(U32*)ref == *(U32*)ip)
+ {
+ const BYTE* reft = ref+MINMATCH;
+ const BYTE* ipt = ip+MINMATCH;
+ const BYTE* startt = ip;
+
+ while (ipt<matchlimit-(STEPSIZE-1))
+ {
+ UARCH diff = AARCH(reft) ^ AARCH(ipt);
+ if (!diff) { ipt+=STEPSIZE; reft+=STEPSIZE; continue; }
+ ipt += LZ4_NbCommonBytes(diff);
+ goto _endCount;
+ }
+ if (LZ4_ARCH64) if ((ipt<(matchlimit-3)) && (A32(reft) == A32(ipt))) { ipt+=4; reft+=4; }
+ if ((ipt<(matchlimit-1)) && (A16(reft) == A16(ipt))) { ipt+=2; reft+=2; }
+ if ((ipt<matchlimit) && (*reft == *ipt)) ipt++;
+_endCount:
+
+ reft = ref;
+ while ((startt>startLimit) && (reft > hc4->base) && (startt[-1] == reft[-1])) {startt--; reft--;}
+
+ if ((ipt-startt) > longest)
+ {
+ longest = ipt-startt;
+ *matchpos = reft;
+ *startpos = startt;
+ }
+ }
+ ref = GETNEXT(ref);
+ }
+
+ return longest;
+}
+
+
+inline static int LZ4_encodeSequence(const BYTE** ip, BYTE** op, const BYTE** anchor, int ml, const BYTE* ref)
+{
+ int length, len;
+ BYTE* token;
+
+ // Encode Literal length
+ length = *ip - *anchor;
+ token = (*op)++;
+ if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *(*op)++ = 255; *(*op)++ = (BYTE)len; }
+ else *token = (length<<ML_BITS);
+
+ // Copy Literals
+ LZ4_BLINDCOPY(*anchor, *op, length);
+
+ // Encode Offset
+ LZ4_WRITE_LITTLEENDIAN_16(*op,*ip-ref);
+
+ // Encode MatchLength
+ len = (int)(ml-MINMATCH);
+ if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *(*op)++ = 255; *(*op)++ = 255; } if (len > 254) { len-=255; *(*op)++ = 255; } *(*op)++ = (BYTE)len; }
+ else *token += len;
+
+ // Prepare next loop
+ *ip += ml;
+ *anchor = *ip;
+
+ return 0;
+}
+
+
+//****************************
+// Compression CODE
+//****************************
+
+int LZ4_compressHCCtx(LZ4HC_Data_Structure* ctx,
+ const char* source,
+ char* dest,
+ int isize)
+{
+ const BYTE* ip = (const BYTE*) source;
+ const BYTE* anchor = ip;
+ const BYTE* const iend = ip + isize;
+ const BYTE* const mflimit = iend - MFLIMIT;
+ const BYTE* const matchlimit = (iend - LASTLITERALS);
+
+ BYTE* op = (BYTE*) dest;
+
+ int ml, ml2, ml3, ml0;
+ const BYTE* ref=NULL;
+ const BYTE* start2=NULL;
+ const BYTE* ref2=NULL;
+ const BYTE* start3=NULL;
+ const BYTE* ref3=NULL;
+ const BYTE* start0;
+ const BYTE* ref0;
+
+ ip++;
+
+ // Main Loop
+ while (ip < mflimit)
+ {
+ ml = LZ4HC_InsertAndFindBestMatch (ctx, ip, matchlimit, (&ref));
+ if (!ml) { ip++; continue; }
+
+ // saved, in case we would skip too much
+ start0 = ip;
+ ref0 = ref;
+ ml0 = ml;
+
+_Search2:
+ if (ip+ml < mflimit)
+ ml2 = LZ4HC_InsertAndGetWiderMatch(ctx, ip + ml - 2, ip + 1, matchlimit, ml, &ref2, &start2);
+ else ml2=ml;
+
+ if (ml2 == ml) // No better match
+ {
+ LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
+ continue;
+ }
+
+ if (start0 < ip)
+ {
+ if (start2 < ip + ml0) // empirical
+ {
+ ip = start0;
+ ref = ref0;
+ ml = ml0;
+ }
+ }
+
+ // Here, start0==ip
+ if ((start2 - ip) < 3) // First Match too small : removed
+ {
+ ml = ml2;
+ ip = start2;
+ ref =ref2;
+ goto _Search2;
+ }
+
+_Search3:
+ // Currently we have :
+ // ml2 > ml1, and
+ // ip1+3 <= ip2 (usually < ip1+ml1)
+ if ((start2 - ip) < OPTIMAL_ML)
+ {
+ int correction;
+ int new_ml = ml;
+ if (new_ml > OPTIMAL_ML) new_ml = OPTIMAL_ML;
+ if (ip+new_ml > start2 + ml2 - MINMATCH) new_ml = start2 - ip + ml2 - MINMATCH;
+ correction = new_ml - (start2 - ip);
+ if (correction > 0)
+ {
+ start2 += correction;
+ ref2 += correction;
+ ml2 -= correction;
+ }
+ }
+ // Now, we have start2 = ip+new_ml, with new_ml=min(ml, OPTIMAL_ML=18)
+
+ if (start2 + ml2 < mflimit)
+ ml3 = LZ4HC_InsertAndGetWiderMatch(ctx, start2 + ml2 - 3, start2, matchlimit, ml2, &ref3, &start3);
+ else ml3=ml2;
+
+ if (ml3 == ml2) // No better match : 2 sequences to encode
+ {
+ // ip & ref are known; Now for ml
+ if (start2 < ip+ml)
+ {
+ if ((start2 - ip) < OPTIMAL_ML)
+ {
+ int correction;
+ if (ml > OPTIMAL_ML) ml = OPTIMAL_ML;
+ if (ip+ml > start2 + ml2 - MINMATCH) ml = start2 - ip + ml2 - MINMATCH;
+ correction = ml - (start2 - ip);
+ if (correction > 0)
+ {
+ start2 += correction;
+ ref2 += correction;
+ ml2 -= correction;
+ }
+ }
+ else
+ {
+ ml = start2 - ip;
+ }
+ }
+ // Now, encode 2 sequences
+ LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
+ ip = start2;
+ LZ4_encodeSequence(&ip, &op, &anchor, ml2, ref2);
+ continue;
+ }
+
+ if (start3 < ip+ml+3) // Not enough space for match 2 : remove it
+ {
+ if (start3 >= (ip+ml)) // can write Seq1 immediately ==> Seq2 is removed, so Seq3 becomes Seq1
+ {
+ if (start2 < ip+ml)
+ {
+ int correction = (ip+ml) - start2;
+ start2 += correction;
+ ref2 += correction;
+ ml2 -= correction;
+ if (ml2 < MINMATCH)
+ {
+ start2 = start3;
+ ref2 = ref3;
+ ml2 = ml3;
+ }
+ }
+
+ LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
+ ip = start3;
+ ref = ref3;
+ ml = ml3;
+
+ start0 = start2;
+ ref0 = ref2;
+ ml0 = ml2;
+ goto _Search2;
+ }
+
+ start2 = start3;
+ ref2 = ref3;
+ ml2 = ml3;
+ goto _Search3;
+ }
+
+ // OK, now we have 3 ascending matches; let's write at least the first one
+ // ip & ref are known; Now for ml
+ if (start2 < ip+ml)
+ {
+ if ((start2 - ip) < (int)ML_MASK)
+ {
+ int correction;
+ if (ml > OPTIMAL_ML) ml = OPTIMAL_ML;
+ if (ip + ml > start2 + ml2 - MINMATCH) ml = start2 - ip + ml2 - MINMATCH;
+ correction = ml - (start2 - ip);
+ if (correction > 0)
+ {
+ start2 += correction;
+ ref2 += correction;
+ ml2 -= correction;
+ }
+ }
+ else
+ {
+ ml = start2 - ip;
+ }
+ }
+ LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);
+
+ ip = start2;
+ ref = ref2;
+ ml = ml2;
+
+ start2 = start3;
+ ref2 = ref3;
+ ml2 = ml3;
+
+ goto _Search3;
+
+ }
+
+ // Encode Last Literals
+ {
+ int lastRun = iend - anchor;
+ if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; }
+ else *op++ = (lastRun<<ML_BITS);
+ memcpy(op, anchor, iend - anchor);
+ op += iend-anchor;
+ }
+
+ // End
+ return (int) (((char*)op)-dest);
+}
+
+
+int LZ4_compressHC(const char* source,
+ char* dest,
+ int isize)
+{
+ void* ctx = LZ4HC_Create((const BYTE*)source);
+ int result = LZ4_compressHCCtx(ctx, source, dest, isize);
+ LZ4HC_Free (&ctx);
+
+ return result;
+}
+
+int LZ4_contextHC_size(void)
+{
+ return sizeof(LZ4HC_Data_Structure);
+}
+
+void LZ4_contextHC_init(void *ctx, const void *base)
+{
+ LZ4HC_Init(ctx, base);
+}
+
+
diff --git a/fs/btrfs/lz4hc.h b/fs/btrfs/lz4hc.h
new file mode 100644
index 0000000..23ab176
--- /dev/null
+++ b/fs/btrfs/lz4hc.h
@@ -0,0 +1,58 @@
+/*
+ LZ4 HC - High Compression Mode of LZ4
+ Copyright (C) 2011-2012, Yann Collet.
+ L-GPL v3 License
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License along
+ with this program; if not, see <http://www.gnu.org/licenses/>,
+ or write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+ You can contact the author at :
+ - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
+ - LZ4-HC source repository : http://code.google.com/p/lz4hc/
+*/
+#pragma once
+
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+
+int LZ4_compressHC (const char* source, char* dest, int isize);
+
+/*
+LZ4_compressHC :
+ return : the number of bytes in compressed buffer dest
+ note : destination buffer must be already allocated.
+ To avoid any problem, size it to handle worst cases situations (input data not compressible)
+ Worst case size evaluation is provided by function LZ4_compressBound() (see "lz4.h")
+*/
+
+
+/* Note :
+Decompression functions are provided within regular LZ4 source code (see "lz4.h") (BSD license)
+*/
+
+int LZ4_compressHCCtx(void* ctx,
+ const char* source,
+ char* dest,
+ int isize);
+
+int LZ4_contextHC_size(void);
+void LZ4_contextHC_init(void *ctx, const void *base);
+
+#if defined (__cplusplus)
+}
+#endif
--
1.7.11
^ permalink raw reply related [flat|nested] 10+ messages in thread* [PATCH 3/5] btrfs: lz4: add lz4_wrapper implementing btrfs compression interface
2012-06-23 8:05 [PATCH 0/5] btrfs: lz4/lz4hc compression Andrew Mahone
2012-06-23 8:05 ` [PATCH 1/5] btrfs: lz4: import lz4/lz4hc C and header files Andrew Mahone
2012-06-23 8:05 ` [PATCH 2/5] btrfs: lz4: add incompat flags and compression types Andrew Mahone
@ 2012-06-23 8:05 ` Andrew Mahone
2012-06-23 8:05 ` [PATCH 4/5] btrfs: lz4: add lz4 files in Makefile Andrew Mahone
` (2 subsequent siblings)
5 siblings, 0 replies; 10+ messages in thread
From: Andrew Mahone @ 2012-06-23 8:05 UTC (permalink / raw)
To: linux-btrfs; +Cc: Andrew Mahone
Signed-off-by: Andrew Mahone <andrew.mahone@gmail.com>
---
fs/btrfs/lz4_wrapper.c | 419 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 419 insertions(+)
create mode 100644 fs/btrfs/lz4_wrapper.c
diff --git a/fs/btrfs/lz4_wrapper.c b/fs/btrfs/lz4_wrapper.c
new file mode 100644
index 0000000..60854de
--- /dev/null
+++ b/fs/btrfs/lz4_wrapper.c
@@ -0,0 +1,419 @@
+/*
+ * Copyright (C) 2008 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/sched.h>
+#include <linux/pagemap.h>
+#include <linux/bio.h>
+#include <linux/highmem.h>
+#include <asm/unaligned.h>
+#include "lz4.h"
+#include "lz4hc.h"
+#include "compression.h"
+
+#define LZ4_HDR_VER 0
+#define LZ4_HDR_LEN (sizeof(__le32))
+
+struct workspace {
+ void *mem; /* work memory for compression */
+ void *buf; /* general-purpose memory for compression */
+ struct list_head list;
+};
+
+static void lz4_free_workspace(struct list_head *ws)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+
+ vfree(workspace->buf);
+ vfree(workspace->mem);
+ kfree(workspace);
+}
+
+static struct list_head *lz4_alloc_workspace_generic(int hi)
+{
+ struct workspace *workspace;
+
+ workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
+ if (!workspace)
+ return ERR_PTR(-ENOMEM);
+
+ if (hi)
+ workspace->mem = vmalloc(LZ4_contextHC_size());
+ else
+ workspace->mem = vmalloc(LZ4_context64k_size());
+ workspace->buf = vmalloc(PAGE_CACHE_SIZE);
+ if (!workspace->mem || !workspace->buf)
+ goto fail;
+
+ INIT_LIST_HEAD(&workspace->list);
+
+ return &workspace->list;
+fail:
+ printk(KERN_WARNING "lz4 workspace alloc failed\n");
+ lz4_free_workspace(&workspace->list);
+ return ERR_PTR(-ENOMEM);
+}
+
+static struct list_head *lz4_alloc_workspace(void)
+{
+ return lz4_alloc_workspace_generic(0);
+}
+
+static struct list_head *lz4hc_alloc_workspace(void)
+{
+ return lz4_alloc_workspace_generic(1);
+}
+
+static inline void write_header(char *buf, size_t len, unsigned char ver)
+{
+ __le32 dlen;
+
+ len &= (1<<24) - 1;
+ len |= ver << 24;
+ dlen = cpu_to_le32(len);
+ memcpy(buf, &dlen, LZ4_HDR_LEN);
+}
+
+static inline void read_header(char *buf, size_t *len, unsigned char *ver)
+{
+ __le32 dlen;
+ u32 val;
+
+ memcpy(&dlen, buf, LZ4_HDR_LEN);
+ val = le32_to_cpu(dlen);
+ *len = val & ((1 << 24) -1);
+ *ver = val >> 24;
+}
+
+#define COUNT_PAGES(length) (PAGE_CACHE_ALIGN((length)) >> PAGE_CACHE_SHIFT)
+
+static int lz4_compress_pages_generic(struct list_head *ws,
+ struct address_space *mapping,
+ u64 start, unsigned long len,
+ struct page **pages,
+ unsigned long nr_dest_pages,
+ unsigned long *out_pages,
+ unsigned long *total_in,
+ unsigned long *total_out,
+ unsigned long max_out, int hi)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ int nr_in_pages = PAGE_CACHE_ALIGN(len) >> PAGE_CACHE_SHIFT;
+ /* FIXME: wasteful by 1 page up to 512k */
+ unsigned long nr_out_pages = COUNT_PAGES(LZ4_compressBound(len + LZ4_HDR_LEN));
+ /* Maximum of 1M chunk: 4096 / 2 / 8 * 4096 */
+ struct page **in_vmap = (struct page**)workspace->buf;
+ struct page **out_vmap = (void*)in_vmap + PAGE_CACHE_SIZE / 2;
+ char *data_in;
+ char *data_out;
+ char *data_out_start;
+ int i;
+ int ret;
+ unsigned out_len;
+
+ {static int xxx=0;if(!xxx){xxx=1;printk(KERN_DEBUG "lz4: using vmap, max_out %ld\n", max_out);}}
+
+ ret = find_get_pages_contig(mapping, start >> PAGE_CACHE_SHIFT,
+ nr_in_pages, in_vmap);
+ if (ret != nr_in_pages) {
+ printk(KERN_WARNING "btrfs: failed to find all input pages for lz4 compression\n");
+ return -1;
+ }
+ data_in = vmap(in_vmap, nr_in_pages, VM_MAP, PAGE_KERNEL);
+ if (!data_in) {
+ printk(KERN_WARNING "btrfs: vmap for lz4 compression input buffer failed.\n");
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < nr_out_pages; i++) {
+ out_vmap[i] = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+ if (!out_vmap[i]) {
+ vunmap(data_in);
+ printk(KERN_WARNING "btrfs: alloc_page for lz4 compression output buffer failed\n");
+ ret = -ENOMEM;
+ goto free_out_pages;
+ }
+
+ }
+ data_out = vmap(out_vmap, nr_out_pages, VM_MAP, PAGE_KERNEL);
+ if (!data_out) {
+ vunmap(data_in);
+ printk(KERN_WARNING "btrfs: vmap for lz4 compression output buffer failed.\n");
+ ret = -ENOMEM;
+ goto free_out_pages;
+ }
+ data_out_start = data_out + LZ4_HDR_LEN;
+ invalidate_kernel_vmap_range(data_in, nr_in_pages << PAGE_CACHE_SHIFT);
+
+ if (hi) {
+ LZ4_contextHC_init(workspace->mem, data_in);
+ out_len = LZ4_compressHCCtx(workspace->mem, data_in,
+ data_out_start, len);
+ if (out_len < 0) {
+ printk(KERN_ERR "btrfs: lz4 compression HC error\n");
+ ret = -1;
+ flush_kernel_vmap_range(data_out, nr_out_pages << PAGE_CACHE_SHIFT);
+ vunmap(data_in);
+ vunmap(data_out);
+ goto free_out_pages;
+ }
+ } else if (len < 64 * 1024) {
+ out_len = LZ4_compress64kCtx(&workspace->mem, data_in,
+ data_out_start, len);
+ if (out_len < 0) {
+ printk(KERN_ERR "btrfs: lz4 compression 64k error\n");
+ ret = -1;
+ flush_kernel_vmap_range(data_out, nr_out_pages << PAGE_CACHE_SHIFT);
+ vunmap(data_in);
+ vunmap(data_out);
+ goto free_out_pages;
+ }
+ } else {
+ out_len = LZ4_compressCtx(&workspace->mem, data_in,
+ data_out_start, len);
+ if (out_len < 0) {
+ printk(KERN_ERR "btrfs: lz4 compression error\n");
+ ret = -1;
+ flush_kernel_vmap_range(data_out, nr_out_pages << PAGE_CACHE_SHIFT);
+ vunmap(data_in);
+ vunmap(data_out);
+ goto free_out_pages;
+ }
+ }
+
+ write_header(data_out, len, LZ4_HDR_VER);
+
+ *total_out = out_len + LZ4_HDR_LEN;
+ *total_in = len;
+ *out_pages = COUNT_PAGES(*total_out);
+
+ ret = 0;
+ if (*out_pages > nr_dest_pages) {
+ vunmap(data_in);
+ for (i = 0; i < nr_in_pages; i++)
+ page_cache_release(in_vmap[i]);
+ flush_kernel_vmap_range(data_out, nr_out_pages << PAGE_CACHE_SHIFT);
+ vunmap(data_out);
+ ret = -1;
+ goto free_out_pages;
+ }
+
+ vunmap(data_in);
+ for (i = 0; i < nr_in_pages; i++)
+ page_cache_release(in_vmap[i]);
+
+ flush_kernel_vmap_range(data_out, nr_out_pages << PAGE_CACHE_SHIFT);
+ vunmap(data_out);
+ for (i = 0; i < min(*out_pages, nr_dest_pages); i++)
+ pages[i] = out_vmap[i];
+ for (; i < nr_out_pages; i++)
+ __free_pages(out_vmap[i], 0);
+
+ return ret;
+
+free_out_pages:
+ for (i = 0; i < nr_out_pages; i++)
+ if(out_vmap[i])
+ page_cache_release(out_vmap[i]);
+ else
+ break;
+ *out_pages = 0;
+ return ret;
+}
+
+static int lz4_compress_pages(struct list_head *ws,
+ struct address_space *mapping,
+ u64 start, unsigned long len,
+ struct page **pages,
+ unsigned long nr_dest_pages,
+ unsigned long *out_pages,
+ unsigned long *total_in,
+ unsigned long *total_out,
+ unsigned long max_out)
+{
+ return lz4_compress_pages_generic(ws, mapping, start, len, pages,
+ nr_dest_pages, out_pages, total_in, total_out,
+ max_out, 0);
+}
+
+static int lz4hc_compress_pages(struct list_head *ws,
+ struct address_space *mapping,
+ u64 start, unsigned long len,
+ struct page **pages,
+ unsigned long nr_dest_pages,
+ unsigned long *out_pages,
+ unsigned long *total_in,
+ unsigned long *total_out,
+ unsigned long max_out)
+{
+ return lz4_compress_pages_generic(ws, mapping, start, len, pages,
+ nr_dest_pages, out_pages, total_in, total_out,
+ max_out, 1);
+}
+
+static int lz4_decompress_biovec(struct list_head *ws,
+ struct page **pages_in,
+ u64 disk_start,
+ struct bio_vec *bvec,
+ int vcnt,
+ size_t srclen)
+{
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
+ PAGE_CACHE_SIZE;
+ int ret;
+ size_t orig_len;
+ unsigned char ver;
+
+ struct page **out_vmap = (struct page**)workspace->buf;
+ struct page **extra_pages = workspace->buf + PAGE_CACHE_SIZE / 2;
+ char *data_in_start;
+ char *data_in = NULL;
+ char *data_out = NULL;
+ int i, j, extra_pages_used = 0;
+
+ data_in = vmap(pages_in, total_pages_in, VM_MAP, PAGE_KERNEL);
+ if (!data_in) {
+ printk(KERN_WARNING "btrfs: vmap for lz4 decompression output buffer failed.\n");
+ return -ENOMEM;
+ }
+ invalidate_kernel_vmap_range(data_in, total_pages_in << PAGE_CACHE_SHIFT);
+ data_in_start = data_in + LZ4_HDR_LEN;
+ read_header(data_in, &orig_len, &ver);
+ if (ver != LZ4_HDR_VER) {
+ printk(KERN_ERR "btrfs: invalid lz4 header version %hhu\n", ver);
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ for (i = 0, j = 0; i < COUNT_PAGES(orig_len); i++) {
+ if (j < vcnt && page_offset(bvec[j].bv_page) - disk_start == i << PAGE_CACHE_SHIFT) {
+ out_vmap[i] = bvec[j].bv_page;
+ j++;
+ } else {
+ out_vmap[i] = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+ if (out_vmap[i] == NULL) {
+ printk(KERN_ERR "btrfs: extra page allocation for lz4 decompression "
+ "failed\n");
+ ret = -ENOMEM;
+ goto fail;
+ }
+ extra_pages[extra_pages_used++] = out_vmap[i];
+ }
+ }
+
+ data_out = vmap(out_vmap, COUNT_PAGES(orig_len),
+ VM_MAP, PAGE_KERNEL);
+ if (!data_out) {
+ printk(KERN_WARNING "btrfs: vmap for lz4 decompression output buffer failed.\n");
+ ret = -ENOMEM;
+ goto fail;
+ }
+
+ ret = LZ4_uncompress(data_in_start, data_out, orig_len);
+ if (ret < 0) {
+ printk(KERN_ERR "btrfs: lz4 decompress error\n");
+ ret = -EIO;
+ goto fail;
+ }
+
+ flush_kernel_vmap_range(data_out, orig_len);
+ vunmap(data_in);
+ vunmap(data_out);
+ for (i = 0; i < extra_pages_used ; i++)
+ __free_page(extra_pages[i]);
+ for (i = 0; i < vcnt; i++)
+ flush_dcache_page(bvec[i].bv_page);
+
+ return 0;
+
+fail:
+ if (data_in)
+ vunmap(data_in);
+ if (data_out)
+ vunmap(data_out);
+ for (i = 0; i < extra_pages_used; i++)
+ __free_page(extra_pages[i]);
+ return ret;
+}
+
+static int lz4_decompress(struct list_head *ws, unsigned char *data_in,
+ struct page *dest_page,
+ unsigned long start_byte,
+ size_t srclen, size_t destlen)
+{
+ size_t out_len;
+ unsigned char ver;
+ int ret = 0;
+ char *kaddr = NULL;
+ unsigned long bytes;
+
+ if (srclen < LZ4_HDR_LEN)
+ return -EIO;
+
+ kaddr = kmap_atomic(dest_page);
+ if (!kaddr) {
+ printk(KERN_ERR "btrfs: kmap_atomic failed in lz4_decompress\n");
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ read_header(data_in, &out_len, &ver);
+ data_in += LZ4_HDR_LEN;
+ if (ver != LZ4_HDR_VER) {
+ printk(KERN_ERR "btrfs: lz4 unknown container version found\n");
+ return -EIO;
+ }
+ ret = LZ4_uncompress(data_in, kaddr, out_len);
+ if (ret < 0) {
+ ret = -EIO;
+ goto out;
+ }
+ else
+ ret = 0;
+
+ if (start_byte) {
+ bytes = min_t(unsigned long, destlen, out_len - start_byte);
+ memmove(kaddr, kaddr + start_byte, bytes);
+ }
+
+out:
+ if (kaddr)
+ kunmap_atomic(kaddr);
+ return ret;
+}
+
+struct btrfs_compress_op btrfs_lz4_compress = {
+ .alloc_workspace = lz4_alloc_workspace,
+ .free_workspace = lz4_free_workspace,
+ .compress_pages = lz4_compress_pages,
+ .decompress_biovec = lz4_decompress_biovec,
+ .decompress = lz4_decompress,
+};
+
+struct btrfs_compress_op btrfs_lz4hc_compress = {
+ .alloc_workspace = lz4hc_alloc_workspace,
+ .free_workspace = lz4_free_workspace,
+ .compress_pages = lz4hc_compress_pages,
+ .decompress_biovec = lz4_decompress_biovec,
+ .decompress = lz4_decompress,
+};
--
1.7.11
^ permalink raw reply related [flat|nested] 10+ messages in thread