b1d068470b
isofs now uses an in-memory directory listing built on-the-fly instead of parsing the ISO 9660 data structures over and over for almost every request. This yields huge performance improvements. The directory listing is allocated dynamically, but Minix servers aren't normally supposed to do that because critical servers would crash if the system runs out of memory. isofs is quite frugal, won't allocate memory after having the whole directory tree cached and is not that critical (its most important job is to serve as a root file system during installation). The benefits and elegance of this scheme far outweights this small problem in practice. Change-Id: I13d070388c07d274cbee0645cbc50295c447c5b6
77 lines
1.9 KiB
C
77 lines
1.9 KiB
C
#include "inc.h"
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static int search_dir(
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struct inode *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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/*
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* The search_dir function performs the operation of searching for the
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* component ``string" in ldir_ptr. It returns the response and the
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* number of the inode in numb.
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*/
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int r, i;
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/*
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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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*/
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if ((ldir_ptr->i_stat.st_mode & S_IFMT) != S_IFDIR)
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return ENOTDIR;
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r = read_directory(ldir_ptr);
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if (r != OK)
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return r;
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if (strcmp(".", string) == 0) {
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*numb = ldir_ptr->i_stat.st_ino;
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return OK;
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}
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/* Walk the directory listing. */
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for (i = 0; i < ldir_ptr->dir_size; i++) {
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if (strcmp(string, ldir_ptr->dir_contents[i].name) == 0) {
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*numb = ldir_ptr->dir_contents[i].i_node->i_stat.st_ino;
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return OK;
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}
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}
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return ENOENT;
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}
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int fs_lookup(ino_t dir_nr, char *name, struct fsdriver_node *node,
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int *is_mountpt)
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{
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/* Given a directory and a component of a path, look up the component
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* in the directory, find the inode, open it, and return its details.
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*/
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struct inode *dirp, *rip;
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ino_t ino_nr;
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int r;
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/* Find the starting inode. */
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if ((dirp = get_inode(dir_nr)) == NULL)
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return EINVAL;
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/* Look up the directory entry. */
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if ((r = search_dir(dirp, name, &ino_nr)) != OK)
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return r;
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/* The component has been found in the directory. Get the inode. */
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if ((rip = open_inode(ino_nr)) == NULL)
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return EIO; /* FIXME: this could have multiple causes */
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/* Return its details to the caller. */
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node->fn_ino_nr = rip->i_stat.st_ino;
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node->fn_mode = rip->i_stat.st_mode;
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node->fn_size = rip->i_stat.st_size;
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node->fn_uid = rip->i_stat.st_uid;
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node->fn_gid = rip->i_stat.st_gid;
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node->fn_dev = rip->i_stat.st_rdev;
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*is_mountpt = rip->i_mountpoint;
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return OK;
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}
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