PSARC 2007/569 lofi(7D) compression support
6618343 lofi compression support

*** 89,98 ****
--- 89,102 ----
   *
   *      li.li_minor = 0;
   *      ioctl(ld, LOFI_GET_MAXMINOR, &li);
   *      maxminor = li.li_minor;
   *
+  *      strcpy(li.li_filename, "somefilename");
+  *      li.li_minor = 0;
+  *      ioctl(ld, LOFI_CHECK_COMPRESSED, &li);
+  *
   * If the 'li_force' flag is set for any of the LOFI_UNMAP_* commands, then if
   * the device is busy, the underlying vnode will be closed, and any subsequent
   * operations will fail.  It will behave as if the device had been forcibly
   * removed, so the DKIOCSTATE ioctl will return DKIO_DEV_GONE.  When the device
   * is last closed, it will be torn down.
*** 103,113 ****
   */
  
  struct lofi_ioctl {
          uint32_t        li_minor;
          boolean_t       li_force;
!         char    li_filename[MAXPATHLEN + 1];
  };
  
  #define LOFI_IOC_BASE           (('L' << 16) | ('F' << 8))
  
  #define LOFI_MAP_FILE           (LOFI_IOC_BASE | 0x01)
--- 107,118 ----
   */
  
  struct lofi_ioctl {
          uint32_t        li_minor;
          boolean_t       li_force;
!         char    li_filename[MAXPATHLEN];
!         char    li_algorithm[MAXPATHLEN];
  };
  
  #define LOFI_IOC_BASE           (('L' << 16) | ('F' << 8))
  
  #define LOFI_MAP_FILE           (LOFI_IOC_BASE | 0x01)
*** 115,132 ****
--- 120,142 ----
  #define LOFI_UNMAP_FILE         (LOFI_IOC_BASE | 0x03)
  #define LOFI_UNMAP_FILE_MINOR   (LOFI_IOC_BASE | 0x04)
  #define LOFI_GET_FILENAME       (LOFI_IOC_BASE | 0x05)
  #define LOFI_GET_MINOR          (LOFI_IOC_BASE | 0x06)
  #define LOFI_GET_MAXMINOR       (LOFI_IOC_BASE | 0x07)
+ #define LOFI_CHECK_COMPRESSED   (LOFI_IOC_BASE | 0x08)
  
  /*
   * file types that might be usable with lofi, maybe. Only regular
   * files are documented though.
   */
  #define S_ISLOFIABLE(mode) \
          (S_ISREG(mode) || S_ISBLK(mode) || S_ISCHR(mode))
  
+ #define SEGHDR          1
+ #define COMPRESSED      1
+ #define UNCOMPRESSED    0
+ 
  #if defined(_KERNEL)
  
  /*
   * We limit the maximum number of active lofi devices to 128, which seems very
   * large. You can tune this by changing lofi_max_files in /etc/system.
*** 156,169 ****
          kstat_t         *ls_kstat;
          kmutex_t        ls_kstat_lock;
          struct dk_geom  ls_dkg;
          struct vtoc     ls_vtoc;
          struct dk_cinfo ls_ci;
  };
  
! #endif
  
  #ifdef  __cplusplus
  }
  #endif
  
  #endif  /* _SYS_LOFI_H */
--- 166,251 ----
          kstat_t         *ls_kstat;
          kmutex_t        ls_kstat_lock;
          struct dk_geom  ls_dkg;
          struct vtoc     ls_vtoc;
          struct dk_cinfo ls_ci;
+ 
+         /* the following fields are required for compression support */
+ 
+         /*
+          * index into lofi_compress_table for the compression algorithm
+          * used
+          */
+         int             ls_comp_algorithm_index;
+         uint32_t        ls_comp_algorithm_len;
+         /* size of an uncompressed segment */
+         uint32_t        ls_uncomp_seg_sz;
+         /* number of index entries */
+         uint32_t        ls_comp_index_sz;
+         /* exponent for byte shift, power of 2 */
+         uint32_t        ls_comp_seg_shift;
+         /*
+          * size of the last uncompressed segment (the file may
+          * not be an exact multiple of the segment size ls_uncomp_seg_sz)
+          */
+         uint32_t        ls_uncomp_last_seg_sz;
+         /*
+          * the offset in the file where the header ends and the
+          * actual compressed data begins. The segment offsets in
+          * the index do not account for the header so this value must
+          * be added
+          */
+         uint64_t        ls_comp_offbase;
+         /*
+          * the array holding the segment index. This is a pointer
+          * into ls_comp_index_data
+          */
+         uint64_t        *ls_comp_seg_index;
+         /*
+          * holds the index pages loaded from the file. This is aligned
+          * on a disk block boundary so lsecomp_seg_index above is used
+          * to point to the actual array
+          */
+         caddr_t         ls_comp_index_data;
+         /* size of ls_comp_index_data */
+         uint32_t        ls_comp_index_data_sz;
+         /*
+          * incase of compressed files, ls_vp_size above is
+          * tweaked to represent the actual uncompressed file
+          * size so that fake_disk_geometry gives the correct
+          * values. However we need the actual compressed file
+          * size while faulting in pages from the compressed
+          * file in lofi_mapped_rdwr
+          */
+         u_offset_t      ls_vp_comp_size;
  };
  
! #endif  /* _KERNEL */
  
+ /*
+  * Common signature for all lofi compress functions
+  */
+ typedef int lofi_compress_func_t(void *src, size_t srclen, void *dst,
+         size_t *destlen, int level);
+ 
+ /*
+  * Information about each compression function
+  */
+ typedef struct lofi_compress_info {
+         lofi_compress_func_t    *l_decompress;
+         lofi_compress_func_t    *l_compress;
+         int                     l_level;
+         char                    *l_name;        /* algorithm name */
+ } lofi_compress_info_t;
+ 
+ enum lofi_compress {
+         LOFI_COMPRESS_GZIP = 0,
+         LOFI_COMPRESS_GZIP_6 = 1,
+         LOFI_COMPRESS_GZIP_9 = 2,
+         LOFI_COMPRESS_FUNCTIONS
+ };
+ 
  #ifdef  __cplusplus
  }
  #endif
  
  #endif  /* _SYS_LOFI_H */