1 /* VTreeFS - extra.c - per-inode storage of arbitrary extra data */ 2 3 #include "inc.h" 4 5 /* 6 * Right now, we maintain the extra data (if requested) as a separate buffer, 7 * so that we don't have to make the inode structure variable in size. Later, 8 * if for example the maximum node name length becomes a runtime setting, we 9 * could reconsider this. 10 */ 11 static char *extra_ptr = NULL; 12 static size_t extra_size = 0; /* per inode */ 13 14 /* 15 * Initialize memory to store extra data. 16 */ 17 int 18 init_extra(unsigned int nr_inodes, size_t inode_extra) 19 { 20 21 if (extra_size == 0) 22 return OK; 23 24 if ((extra_ptr = malloc(nr_inodes * inode_extra)) == NULL) 25 return ENOMEM; 26 27 extra_size = inode_extra; 28 29 return OK; 30 } 31 32 /* 33 * Initialize the extra data for the given inode to zero. 34 */ 35 void 36 clear_inode_extra(struct inode * node) 37 { 38 39 if (extra_size == 0) 40 return; 41 42 memset(&extra_ptr[node->i_num * extra_size], 0, extra_size); 43 } 44 45 /* 46 * Retrieve a pointer to the extra data for the given inode. 47 */ 48 void * 49 get_inode_extra(const struct inode * node) 50 { 51 52 if (extra_size == 0) 53 return NULL; 54 55 return (void *)&extra_ptr[node->i_num * extra_size]; 56 } 57