Add primary cache management feature to libminixfs as mfs and ext2 currently do separately, remove cache code from mfs and ext2, and make them use the libminixfs interface. This makes all fields of the buf struct private to libminixfs and FS clients aren't supposed to access them at all. Only the opaque 'void *data' field (the FS block contents, used to be called bp) is to be accessed by the FS client. The main purpose is to implement the interface to the 2ndary vm cache just once, get rid of some code duplication, and add a little abstraction to reduce the code inertia of the whole caching business. Some minor sanity checking and prohibition done by mfs in this code as removed from the generic primary cache code as a result: - checking all inodes are not in use when allocating/resizing the cache - checking readonly filesystems aren't written to - checking the superblock isn't written to on mounted filesystems The minixfslib code relies on fs_blockstats() in the client filesystem to return some FS usage information.
372 lines
9.7 KiB
C
372 lines
9.7 KiB
C
#include "inc.h"
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#include <string.h>
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#include <minix/com.h>
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#include <minix/vfsif.h>
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#include "buf.h"
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static char *get_name(char *name, char string[NAME_MAX+1]);
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static int parse_path(ino_t dir_ino, ino_t root_ino, int flags, struct
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dir_record **res_inop, size_t *offsetp);
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/*===========================================================================*
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* fs_lookup *
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*===========================================================================*/
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int fs_lookup() {
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cp_grant_id_t grant;
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int r, len, flags;
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size_t offset;
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ino_t dir_ino, root_ino;
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struct dir_record *dir;
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grant = fs_m_in.REQ_GRANT;
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len = fs_m_in.REQ_PATH_LEN; /* including terminating nul */
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dir_ino = fs_m_in.REQ_DIR_INO;
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root_ino = fs_m_in.REQ_ROOT_INO;
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flags = fs_m_in.REQ_FLAGS;
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caller_uid = fs_m_in.REQ_UID;
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caller_gid = fs_m_in.REQ_GID;
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/* Check length. */
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if(len > sizeof(user_path)) return(E2BIG); /* too big for buffer */
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if(len < 1) return(EINVAL); /* too small */
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/* Copy the pathname and set up caller's user and group id */
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r = sys_safecopyfrom(VFS_PROC_NR, grant, 0, (vir_bytes) user_path,
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(phys_bytes) len);
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if (r != OK) {
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printf("ISOFS %s:%d sys_safecopyfrom failed: %d\n",
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__FILE__, __LINE__, r);
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return(r);
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}
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/* Verify this is a null-terminated path. */
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if(user_path[len-1] != '\0') return(EINVAL);
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/* Lookup inode */
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dir = NULL;
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offset = 0;
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r = parse_path(dir_ino, root_ino, flags, &dir, &offset);
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if (r == ELEAVEMOUNT) {
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/* Report offset and the error */
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fs_m_out.RES_OFFSET = offset;
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fs_m_out.RES_SYMLOOP = 0;
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return(r);
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}
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if (r != OK && r != EENTERMOUNT) return(r);
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fs_m_out.RES_INODE_NR = ID_DIR_RECORD(dir);
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fs_m_out.RES_MODE = dir->d_mode;
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fs_m_out.RES_FILE_SIZE_LO = dir->d_file_size;
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fs_m_out.RES_SYMLOOP = 0;
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fs_m_out.RES_UID = SYS_UID; /* root */
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fs_m_out.RES_GID = SYS_GID; /* operator */
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if (r == EENTERMOUNT) {
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fs_m_out.RES_OFFSET = offset;
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release_dir_record(dir);
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}
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return(r);
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}
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/* The search dir actually performs the operation of searching for the
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* compoent ``string" in ldir_ptr. It returns the response and the number of
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* the inode in numb. */
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/*===========================================================================*
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* search_dir *
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*===========================================================================*/
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int search_dir(ldir_ptr,string,numb)
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register struct dir_record *ldir_ptr; /* dir record parent */
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char string[NAME_MAX]; /* component to search for */
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ino_t *numb; /* pointer to new dir record */
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{
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struct dir_record *dir_tmp;
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register struct buf *bp;
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int pos;
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char* comma_pos = NULL;
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char tmp_string[NAME_MAX];
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/* This function search a particular element (in string) in a inode and
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* return its number */
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/* Initialize the tmp array */
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memset(tmp_string,'\0',NAME_MAX);
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if ((ldir_ptr->d_mode & I_TYPE) != I_DIRECTORY) {
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return(ENOTDIR);
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}
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if (strcmp(string,".") == 0) {
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*numb = ID_DIR_RECORD(ldir_ptr);
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return OK;
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}
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if (strcmp(string,"..") == 0 && ldir_ptr->loc_extent_l == v_pri.dir_rec_root->loc_extent_l) {
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*numb = ROOT_INO_NR;
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/* *numb = ID_DIR_RECORD(ldir_ptr); */
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return OK;
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}
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/* Read the dir's content */
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pos = ldir_ptr->ext_attr_rec_length;
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bp = get_block(ldir_ptr->loc_extent_l);
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if (bp == NULL)
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return EINVAL;
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while (pos < v_pri.logical_block_size_l) {
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if ((dir_tmp = get_free_dir_record()) == NULL) {
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put_block(bp);
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return EINVAL;
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}
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if (create_dir_record(dir_tmp,b_data(bp) + pos,
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ldir_ptr->loc_extent_l*v_pri.logical_block_size_l + pos) == EINVAL)
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return EINVAL;
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if (dir_tmp->length == 0) {
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release_dir_record(dir_tmp);
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put_block(bp);
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return EINVAL;
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}
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memcpy(tmp_string,dir_tmp->file_id,dir_tmp->length_file_id);
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comma_pos = strchr(tmp_string,';');
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if (comma_pos != NULL)
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*comma_pos = 0;
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else
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tmp_string[dir_tmp->length_file_id] = 0;
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if (tmp_string[strlen(tmp_string) - 1] == '.')
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tmp_string[strlen(tmp_string) - 1] = '\0';
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if (strcmp(tmp_string,string) == 0 ||
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(dir_tmp->file_id[0] == 1 && strcmp(string,"..") == 0)) {
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/* If the element is found or we are searchig for... */
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if (dir_tmp->loc_extent_l == dir_records->loc_extent_l) {
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/* In this case the inode is a root because the parent
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* points to the same location than the inode. */
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*numb = 1;
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release_dir_record(dir_tmp);
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put_block(bp);
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return OK;
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}
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if (dir_tmp->ext_attr_rec_length != 0) {
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dir_tmp->ext_attr = get_free_ext_attr();
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create_ext_attr(dir_tmp->ext_attr,b_data(bp));
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}
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*numb = ID_DIR_RECORD(dir_tmp);
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release_dir_record(dir_tmp);
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put_block(bp);
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return OK;
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}
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pos += dir_tmp->length;
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release_dir_record(dir_tmp);
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}
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put_block(bp);
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return EINVAL;
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}
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/*===========================================================================*
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* parse_path *
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*===========================================================================*/
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static int parse_path(dir_ino, root_ino, flags, res_inop, offsetp)
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ino_t dir_ino;
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ino_t root_ino;
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int flags;
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struct dir_record **res_inop;
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size_t *offsetp;
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{
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int r;
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char string[NAME_MAX+1];
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char *cp, *ncp;
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struct dir_record *start_dir, *old_dir;
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/* Find starting inode inode according to the request message */
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if ((start_dir = get_dir_record(dir_ino)) == NULL) {
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printf("ISOFS: couldn't find starting inode %lu\n", dir_ino);
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return(ENOENT);
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}
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cp = user_path;
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/* Scan the path component by component. */
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while (TRUE) {
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if (cp[0] == '\0') {
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/* Empty path */
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*res_inop= start_dir;
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*offsetp += cp-user_path;
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/* Return EENTERMOUNT if we are at a mount point */
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if (start_dir->d_mountpoint)
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return EENTERMOUNT;
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return OK;
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}
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if (cp[0] == '/') {
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/* Special case code. If the remaining path consists of just
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* slashes, we need to look up '.'
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*/
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while(cp[0] == '/')
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cp++;
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if (cp[0] == '\0') {
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strlcpy(string, ".", NAME_MAX + 1);
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ncp = cp;
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}
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else
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ncp = get_name(cp, string);
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} else
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/* Just get the first component */
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ncp = get_name(cp, string);
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/* Special code for '..'. A process is not allowed to leave a chrooted
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* environment. A lookup of '..' at the root of a mounted filesystem
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* has to return ELEAVEMOUNT.
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*/
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if (strcmp(string, "..") == 0) {
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/* This condition is not necessary since it will never be the root filesystem */
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/* if (start_dir == dir_records) { */
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/* cp = ncp; */
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/* continue; /\* Just ignore the '..' at a process' */
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/* * root. */
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/* *\/ */
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/* } */
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if (start_dir == dir_records) {
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/* Climbing up mountpoint */
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release_dir_record(start_dir);
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*res_inop = NULL;
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*offsetp += cp-user_path;
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return ELEAVEMOUNT;
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}
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} else {
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/* Only check for a mount point if we are not looking for '..'. */
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if (start_dir->d_mountpoint) {
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*res_inop= start_dir;
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*offsetp += cp-user_path;
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return EENTERMOUNT;
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}
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}
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/* There is more path. Keep parsing. */
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old_dir = start_dir;
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r = advance(old_dir, string, &start_dir);
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if (r != OK) {
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release_dir_record(old_dir);
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return r;
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}
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release_dir_record(old_dir);
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cp = ncp;
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}
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}
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/*===========================================================================*
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* advance *
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*===========================================================================*/
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int advance(dirp, string, resp)
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struct dir_record *dirp; /* inode for directory to be searched */
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char string[NAME_MAX]; /* component name to look for */
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struct dir_record **resp; /* resulting inode */
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{
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/* Given a directory and a component of a path, look up the component in
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* the directory, find the inode, open it, and return a pointer to its inode
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* slot.
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*/
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register struct dir_record *rip = NULL;
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int r;
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ino_t numb;
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/* If 'string' is empty, yield same inode straight away. */
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if (string[0] == '\0') {
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return ENOENT;
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}
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/* Check for NULL. */
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if (dirp == NULL) {
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return EINVAL;
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}
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/* If 'string' is not present in the directory, signal error. */
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if ( (r = search_dir(dirp, string, &numb)) != OK) {
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return r;
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}
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/* The component has been found in the directory. Get inode. */
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if ( (rip = get_dir_record((int) numb)) == NULL) {
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return(err_code);
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}
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*resp= rip;
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return OK;
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}
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/*===========================================================================*
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* get_name *
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*===========================================================================*/
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static char *get_name(path_name, string)
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char *path_name; /* path name to parse */
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char string[NAME_MAX+1]; /* component extracted from 'old_name' */
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{
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/* Given a pointer to a path name in fs space, 'path_name', copy the first
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* component to 'string' (truncated if necessary, always nul terminated).
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* A pointer to the string after the first component of the name as yet
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* unparsed is returned. Roughly speaking,
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* 'get_name' = 'path_name' - 'string'.
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*
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* This routine follows the standard convention that /usr/ast, /usr//ast,
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* //usr///ast and /usr/ast/ are all equivalent.
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*/
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size_t len;
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char *cp, *ep;
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cp= path_name;
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/* Skip leading slashes */
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while (cp[0] == '/')
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cp++;
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/* Find the end of the first component */
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ep= cp;
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while(ep[0] != '\0' && ep[0] != '/')
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ep++;
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len= ep-cp;
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/* Truncate the amount to be copied if it exceeds NAME_MAX */
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if (len > NAME_MAX)
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len= NAME_MAX;
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/* Special case of the string at cp is empty */
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if (len == 0)
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{
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/* Return "." */
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strlcpy(string, ".", NAME_MAX + 1);
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}
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else
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{
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memcpy(string, cp, len);
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string[len]= '\0';
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}
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return ep;
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}
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