reactos/drivers/filesystems/ext2_new/inc/linux/ext4_ext.h

   1 #ifndef _LINUX_EXT4_EXT
   2 #define _LINUX_EXT4_EXT
   3
   4 /*
   5  * This is the extent tail on-disk structure.
   6  * All other extent structures are 12 bytes long.  It turns out that
   7  * block_size % 12 >= 4 for at least all powers of 2 greater than 512, which
   8  * covers all valid ext4 block sizes.  Therefore, this tail structure can be
   9  * crammed into the end of the block without having to rebalance the tree.
  10  */
  11 struct ext4_extent_tail {
  12         uint32_t et_checksum; /* crc32c(uuid+inum+extent_block) */
  13 };
  14
  15 /*
  16  * This is the extent on-disk structure.
  17  * It's used at the bottom of the tree.
  18  */
  19 typedef struct ext4_extent {
  20     uint32_t ee_block; /* first logical block extent covers */
  21     uint16_t ee_len; /* number of blocks covered by extent */
  22     uint16_t ee_start_hi; /* high 16 bits of physical block */
  23     uint32_t ee_start_lo; /* low 32 bits of physical block */
  24 } __attribute__ ((__packed__)) EXT4_EXTENT;
  25
  26 /*
  27  * This is index on-disk structure.
  28  * It's used at all the levels except the bottom.
  29  */
  30 typedef struct ext4_extent_idx {
  31     uint32_t  ei_block;       /* index covers logical blocks from 'block' */
  32     uint32_t  ei_leaf_lo;     /* pointer to the physical block of the next *
  33                                  * level. leaf or next index could be there */
  34     uint16_t  ei_leaf_hi;     /* high 16 bits of physical block */
  35     uint16_t   ei_unused;
  36 }__attribute__ ((__packed__)) EXT4_EXTENT_IDX;
  37
  38 /*
  39  * Each block (leaves and indexes), even inode-stored has header.
  40  */
  41 typedef struct ext4_extent_header {
  42     uint16_t  eh_magic;       /* probably will support different formats */
  43     uint16_t  eh_entries;     /* number of valid entries */
  44     uint16_t  eh_max;         /* capacity of store in entries */
  45     uint16_t  eh_depth;       /* has tree real underlying blocks? */
  46     uint32_t  eh_generation;  /* generation of the tree */
  47 }__attribute__ ((__packed__)) EXT4_EXTENT_HEADER;
  48
  49
  50 #define EXT4_EXT_MAGIC          0xf30a
  51 #define get_ext4_header(i)      ((struct ext4_extent_header *) (i)->i_block)
  52
  53 #define EXT4_EXTENT_TAIL_OFFSET(hdr)                                           \
  54         (sizeof(struct ext4_extent_header) +                                   \
  55          (sizeof(struct ext4_extent) * (hdr)->eh_max))
  56
  57 static inline struct ext4_extent_tail *
  58 find_ext4_extent_tail(struct ext4_extent_header *eh)
  59 {
  60         return (struct ext4_extent_tail *)(((char *)eh) +
  61                                            EXT4_EXTENT_TAIL_OFFSET(eh));
  62 }
  63
  64 /*
  65  * Array of ext4_ext_path contains path to some extent.
  66  * Creation/lookup routines use it for traversal/splitting/etc.
  67  * Truncate uses it to simulate recursive walking.
  68  */
  69 struct ext4_ext_path
  70 {
  71         ext4_fsblk_t p_block;
  72         int p_depth;
  73         int p_maxdepth;
  74         struct ext4_extent *p_ext;
  75         struct ext4_extent_idx *p_idx;
  76         struct ext4_extent_header *p_hdr;
  77         struct buffer_head *p_bh;
  78 };
  79
  80 /*
  81  * structure for external API
  82  */
  83
  84 /*
  85  * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
  86  * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
  87  * MSB of ee_len field in the extent datastructure to signify if this
  88  * particular extent is an initialized extent or an uninitialized (i.e.
  89  * preallocated).
  90  * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an
  91  * uninitialized extent.
  92  * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
  93  * uninitialized one. In other words, if MSB of ee_len is set, it is an
  94  * uninitialized extent with only one special scenario when ee_len = 0x8000.
  95  * In this case we can not have an uninitialized extent of zero length and
  96  * thus we make it as a special case of initialized extent with 0x8000 length.
  97  * This way we get better extent-to-group alignment for initialized extents.
  98  * Hence, the maximum number of blocks we can have in an *initialized*
  99  * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767).
 100  */
 101 #define EXT_INIT_MAX_LEN (1UL << 15)
 102 #define EXT_UNWRITTEN_MAX_LEN   (EXT_INIT_MAX_LEN - 1)
 103
 104 #define EXT_EXTENT_SIZE sizeof(struct ext4_extent)
 105 #define EXT_INDEX_SIZE sizeof(struct ext4_extent_idx)
 106
 107 #define EXT_FIRST_EXTENT(__hdr__)                                              \
 108         ((struct ext4_extent *)(((char *)(__hdr__)) +                          \
 109                                 sizeof(struct ext4_extent_header)))
 110 #define EXT_FIRST_INDEX(__hdr__)                                               \
 111         ((struct ext4_extent_idx *)(((char *)(__hdr__)) +                      \
 112                                     sizeof(struct ext4_extent_header)))
 113 #define EXT_HAS_FREE_INDEX(__path__)                                           \
 114         ((__path__)->p_hdr->eh_entries < (__path__)->p_hdr->eh_max)
 115 #define EXT_LAST_EXTENT(__hdr__)                                               \
 116         (EXT_FIRST_EXTENT((__hdr__)) + (__hdr__)->eh_entries - 1)
 117 #define EXT_LAST_INDEX(__hdr__)                                                \
 118         (EXT_FIRST_INDEX((__hdr__)) + (__hdr__)->eh_entries - 1)
 119 #define EXT_MAX_EXTENT(__hdr__)                                                \
 120         (EXT_FIRST_EXTENT((__hdr__)) + (__hdr__)->eh_max - 1)
 121 #define EXT_MAX_INDEX(__hdr__)                                                 \
 122         (EXT_FIRST_INDEX((__hdr__)) + (__hdr__)->eh_max - 1)
 123
 124 static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
 125 {
 126         return get_ext4_header(inode);
 127 }
 128
 129 static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
 130 {
 131         return (struct ext4_extent_header *)bh->b_data;
 132 }
 133
 134 static inline unsigned short ext_depth(struct inode *inode)
 135 {
 136         return ext_inode_hdr(inode)->eh_depth;
 137 }
 138
 139 static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext)
 140 {
 141         /* We can not have an uninitialized extent of zero length! */
 142         ext->ee_len |= EXT_INIT_MAX_LEN;
 143 }
 144
 145 static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext)
 146 {
 147         /* Extent with ee_len of 0x8000 is treated as an initialized extent */
 148         return (ext->ee_len > EXT_INIT_MAX_LEN);
 149 }
 150
 151 static inline uint16_t ext4_ext_get_actual_len(struct ext4_extent *ext)
 152 {
 153         return (ext->ee_len <= EXT_INIT_MAX_LEN
 154                     ? ext->ee_len
 155                     : (ext->ee_len - EXT_INIT_MAX_LEN));
 156 }
 157
 158 static inline void ext4_ext_mark_initialized(struct ext4_extent *ext)
 159 {
 160         ext->ee_len = ext4_ext_get_actual_len(ext);
 161 }
 162
 163 static inline void ext4_ext_mark_unwritten(struct ext4_extent *ext)
 164 {
 165         /* We can not have an unwritten extent of zero length! */
 166         ext->ee_len |= EXT_INIT_MAX_LEN;
 167 }
 168
 169 static inline int ext4_ext_is_unwritten(struct ext4_extent *ext)
 170 {
 171         /* Extent with ee_len of 0x8000 is treated as an initialized extent */
 172         return (ext->ee_len > EXT_INIT_MAX_LEN);
 173 }
 174
 175 /*
 176  * ext4_ext_pblock:
 177  * combine low and high parts of physical block number into ext4_fsblk_t
 178  */
 179 static inline ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex)
 180 {
 181         ext4_fsblk_t block;
 182
 183         block = ex->ee_start_lo;
 184         block |= ((ext4_fsblk_t)ex->ee_start_hi << 31) << 1;
 185         return block;
 186 }
 187
 188 /*
 189  * ext4_idx_pblock:
 190  * combine low and high parts of a leaf physical block number into ext4_fsblk_t
 191  */
 192 static inline ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_idx *ix)
 193 {
 194         ext4_fsblk_t block;
 195
 196         block = ix->ei_leaf_lo;
 197         block |= ((ext4_fsblk_t)ix->ei_leaf_hi << 31) << 1;
 198         return block;
 199 }
 200
 201 /*
 202  * ext4_ext_store_pblock:
 203  * stores a large physical block number into an extent struct,
 204  * breaking it into parts
 205  */
 206 static inline void ext4_ext_store_pblock(struct ext4_extent *ex,
 207                                          ext4_fsblk_t pb)
 208 {
 209         ex->ee_start_lo = (uint32_t)(pb & 0xffffffff);
 210         ex->ee_start_hi = (uint16_t)((pb >> 31) >> 1) & 0xffff;
 211 }
 212
 213 /*
 214  * ext4_idx_store_pblock:
 215  * stores a large physical block number into an index struct,
 216  * breaking it into parts
 217  */
 218 static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix,
 219                                          ext4_fsblk_t pb)
 220 {
 221         ix->ei_leaf_lo = (uint32_t)(pb & 0xffffffff);
 222         ix->ei_leaf_hi = (uint16_t)((pb >> 31) >> 1) & 0xffff;
 223 }
 224
 225 #define ext4_ext_dirty(icb, handle, inode, path)                                           \
 226         __ext4_ext_dirty("", __LINE__, (icb), (handle), (inode), (path))
 227
 228 #define INODE_HAS_EXTENT(i) ((i)->i_flags & EXT2_EXTENTS_FL)
 229
 230 static inline uint64_t ext_to_block(EXT4_EXTENT *extent)
 231 {
 232     uint64_t block;
 233
 234     block = (uint64_t)extent->ee_start_lo;
 235     block |= ((uint64_t) extent->ee_start_hi << 31) << 1;
 236
 237     return block;
 238 }
 239
 240 static inline uint64_t idx_to_block(EXT4_EXTENT_IDX *idx)
 241 {
 242     uint64_t block;
 243
 244     block = (uint64_t)idx->ei_leaf_lo;
 245     block |= ((uint64_t) idx->ei_leaf_hi << 31) << 1;
 246
 247     return block;
 248 }
 249
 250
 251 int ext4_ext_get_blocks(void *icb, handle_t *handle, struct inode *inode, ext4_fsblk_t iblock,
 252                         unsigned long max_blocks, struct buffer_head *bh_result,
 253                         int create, int flags);
 254 int ext4_ext_tree_init(void *icb, handle_t *handle, struct inode *inode);
 255 int ext4_ext_remove_space(void *icb, struct inode *inode, unsigned long start);
 256
 257 #endif  /* _LINUX_EXT4_EXT */