sanchayanmaity/minix
1
0
Fork 0
Code Issues Pull requests Packages Projects Releases Wiki Activity
minix/servers/iso9660fs/inode.c
Ben Gras bd3cde4571 Move primary cache code to libminixfs. 
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.
2012-10-23 19:48:38 +02:00

297 lines
8.8 KiB
C
Raw Blame History

/* This file contains all the function that handle the dir records
* (inodes) for the ISO9660 filesystem.*/
#include "inc.h"
#include "buf.h"
#include <minix/vfsif.h>
/*===========================================================================*
* fs_putnode *
*===========================================================================*/
int fs_putnode()
{
/* Find the inode specified by the request message and decrease its counter. */
int count;
struct dir_record *dir = NULL;
dir = get_dir_record(fs_m_in.REQ_INODE_NR);
release_dir_record(dir);
count = fs_m_in.REQ_COUNT;
if (count <= 0) return(EINVAL);
if (count > dir->d_count) {
printf("put_inode: count too high: %d > %d\n", count, dir->d_count);
return(EINVAL);
}
if (dir->d_count > 1)
dir->d_count = dir->d_count - count + 1;/*Keep at least one reference*/
release_dir_record(dir); /* Actual inode release, might be last reference */
return(OK);
}
/*===========================================================================*
* release_dir_record *
*===========================================================================*/
int release_dir_record(dir)
struct dir_record *dir;
{
/* Release a dir record (decrement the counter) */
if (dir == NULL)
return(EINVAL);
if (--dir->d_count == 0) {
if (dir->ext_attr != NULL)
dir->ext_attr->count = 0;
dir->ext_attr = NULL;
dir->d_mountpoint = FALSE;
dir->d_prior = NULL;
if (dir->d_next != NULL)
release_dir_record(dir);
dir->d_next = NULL;
}
return(OK);
}
/*===========================================================================*
* get_free_dir_record *
*===========================================================================*/
struct dir_record *get_free_dir_record(void)
{
/* Get a free dir record */
struct dir_record *dir;
for(dir = dir_records; dir < &dir_records[NR_ATTR_RECS]; dir++) {
if (dir->d_count == 0) { /* The record is free */
dir->d_count = 1; /* Set count to 1 */
dir->ext_attr = NULL;
return(dir);
}
}
return(NULL);
}
/*===========================================================================*
* get_dir_record *
*===========================================================================*/
struct dir_record *get_dir_record(id_dir_record)
ino_t id_dir_record;
{
struct dir_record *dir = NULL;
u32_t address;
int i;
/* Search through the cache if the inode is still present */
for(i = 0; i < NR_DIR_RECORDS && dir == NULL; ++i) {
if (dir_records[i].d_ino_nr == id_dir_record
&& dir_records[i].d_count > 0) {
dir = dir_records + i;
dir->d_count++;
}
}
if (dir == NULL) {
address = (u32_t)id_dir_record;
dir = load_dir_record_from_disk(address);
}
if (dir == NULL) return(NULL);
return(dir);
}
/*===========================================================================*
* get_free_ext_attr *
*===========================================================================*/
struct ext_attr_rec *get_free_ext_attr(void) {
/* Get a free extended attribute structure */
struct ext_attr_rec *dir;
for(dir = ext_attr_recs; dir < &ext_attr_recs[NR_ATTR_RECS]; dir++) {
if (dir->count == 0) { /* The record is free */
dir->count = 1;
return(dir);
}
}
return(NULL);
}
/*===========================================================================*
* create_ext_attr *
*===========================================================================*/
int create_ext_attr(struct ext_attr_rec *ext,char *buffer)
{
/* Fill an extent structure from the data read on the device */
if (ext == NULL) return(EINVAL);
/* In input we have a stream of bytes that are physically read from the
* device. This stream of data is copied to the data structure. */
memcpy(&ext->own_id,buffer,sizeof(u32_t));
memcpy(&ext->group_id,buffer + 4,sizeof(u32_t));
memcpy(&ext->permissions,buffer + 8,sizeof(u16_t));
memcpy(&ext->file_cre_date,buffer + 10,ISO9660_SIZE_VOL_CRE_DATE);
memcpy(&ext->file_mod_date,buffer + 27,ISO9660_SIZE_VOL_MOD_DATE);
memcpy(&ext->file_exp_date,buffer + 44,ISO9660_SIZE_VOL_EXP_DATE);
memcpy(&ext->file_eff_date,buffer + 61,ISO9660_SIZE_VOL_EFF_DATE);
memcpy(&ext->rec_format,buffer + 78,sizeof(u8_t));
memcpy(&ext->rec_attrs,buffer + 79,sizeof(u8_t));
memcpy(&ext->rec_length,buffer + 80,sizeof(u32_t));
memcpy(&ext->system_id,buffer + 84,ISO9660_SIZE_SYS_ID);
memcpy(&ext->system_use,buffer + 116,ISO9660_SIZE_SYSTEM_USE);
memcpy(&ext->ext_attr_rec_ver,buffer + 180,sizeof(u8_t));
memcpy(&ext->len_esc_seq,buffer + 181,sizeof(u8_t));
return(OK);
}
/*===========================================================================*
* create_ext_attr *
*===========================================================================*/
int create_dir_record(dir,buffer,address)
struct dir_record *dir;
char *buffer;
u32_t address;
{
/* Fills a dir record structure from the data read on the device */
/* If the flag assign id is active it will return the id associated;
* otherwise it will return OK. */
short size;
size = buffer[0];
if (dir == NULL) return(EINVAL);
/* The data structure dir record is filled with the stream of data
* that is read. */
dir->length = size;
dir->ext_attr_rec_length = *((u8_t*)buffer + 1);
memcpy(&dir->loc_extent_l,buffer + 2,sizeof(u32_t));
memcpy(&dir->loc_extent_m,buffer + 6,sizeof(u32_t));
memcpy(&dir->data_length_l,buffer + 10,sizeof(u32_t));
memcpy(&dir->data_length_m,buffer + 14,sizeof(u32_t));
memcpy(dir->rec_date,buffer + 18, sizeof(dir->rec_date));
dir->file_flags = *((u8_t*)buffer + 25);
dir->file_unit_size = *((u8_t*)buffer + 26);
dir->inter_gap_size = *((u8_t*)buffer + 27);
dir->vol_seq_number = *((u8_t*)buffer + 28);
dir->length_file_id = *((u8_t*)buffer + 32);
memcpy(dir->file_id,buffer + 33,dir->length_file_id);
dir->ext_attr = NULL;
/* set memory attrs */
if ((dir->file_flags & D_TYPE) == D_DIRECTORY)
dir->d_mode = I_DIRECTORY;
else
dir->d_mode = I_REGULAR;
/* Set permission to read only. Equal for all users. */
dir->d_mode |= R_BIT | X_BIT;
dir->d_mode |= R_BIT << 3 | X_BIT << 3;
dir->d_mode |= R_BIT << 6 | X_BIT << 6;
dir->d_mountpoint = FALSE;
dir->d_next = NULL;
dir->d_prior = NULL;
dir->d_file_size = dir->data_length_l;
/* Set physical address of the dir record */
dir->d_phy_addr = address;
dir->d_ino_nr = (ino_t) address; /* u32_t e ino_t are the same datatype so
* the cast is safe */
return(OK);
}
/*===========================================================================*
* load_dir_record_from_disk *
*===========================================================================*/
struct dir_record *load_dir_record_from_disk(address)
u32_t address;
{
/* This function load a particular dir record from a specific address
* on the device */
int block_nr, offset, block_size, new_pos;
struct buf *bp;
struct dir_record *dir, *dir_next, *dir_parent, *dir_tmp;
char name[NAME_MAX + 1];
char old_name[NAME_MAX + 1];
u32_t new_address, size;
block_size = v_pri.logical_block_size_l; /* Block size */
block_nr = address / block_size; /* Block number from the address */
offset = address % block_size; /* Offset starting from the block */
bp = get_block(block_nr); /* Read the block from the device */
if (bp == NULL)
return(NULL);
dir = get_free_dir_record(); /* Get a free record */
if (dir == NULL)
return(NULL);
/* Fill the dir record with the data read from the device */
create_dir_record(dir,b_data(bp) + offset, address);
/* In case the file is composed of more file sections, load also the
* next section into the structure */
new_pos = offset + dir->length;
dir_parent = dir;
new_address = address + dir->length;
while (new_pos < block_size) {
dir_next = get_free_dir_record();
create_dir_record(dir_next, b_data(bp) + new_pos, new_address);
if (dir_next->length > 0) {
strncpy(name,dir_next->file_id,dir_next->length_file_id);
name[dir_next->length_file_id] = '\0';
strncpy(old_name, dir_parent->file_id,
dir_parent->length_file_id);
old_name[dir_parent->length_file_id] = '\0';
if (strcmp(name, old_name) == 0) {
dir_parent->d_next = dir_next;
dir_next->d_prior = dir_parent;
/* Link the dir records */
dir_tmp = dir_next;
size = dir_tmp->data_length_l;
/* Update the file size */
while (dir_tmp->d_prior != NULL) {
dir_tmp = dir_tmp->d_prior;
size += dir_tmp->data_length_l;
dir_tmp->d_file_size = size;
}
new_pos += dir_parent->length;
new_address += dir_next->length;
dir_parent = dir_next;
} else { /* This is another inode. */
release_dir_record(dir_next);
new_pos = block_size;
}
} else { /* record not valid */
release_dir_record(dir_next);
new_pos = block_size; /* Exit from the while */
}
}
put_block(bp); /* Release the block read. */
return(dir);
}
Reference in a new issue View git blame Copy permalink