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.
255 lines
6.9 KiB
C
255 lines
6.9 KiB
C
/* Created (MFS based):
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* February 2010 (Evgeniy Ivanov)
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*/
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#include "fs.h"
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#include "buf.h"
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#include "inode.h"
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#include "super.h"
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/*===========================================================================*
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* no_sys *
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*===========================================================================*/
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int no_sys()
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{
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/* Somebody has used an illegal system call number */
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printf("no_sys: invalid call %d\n", req_nr);
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return(EINVAL);
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}
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/*===========================================================================*
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* conv2 *
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*===========================================================================*/
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unsigned conv2(norm, w)
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int norm; /* TRUE if no swap, FALSE for byte swap */
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int w; /* promotion of 16-bit word to be swapped */
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{
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/* Possibly swap a 16-bit word between 8086 and 68000 byte order. */
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if (norm) return( (unsigned) w & 0xFFFF);
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return( ((w&BYTE) << 8) | ( (w>>8) & BYTE));
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}
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/*===========================================================================*
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* conv4 *
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*===========================================================================*/
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long conv4(norm, x)
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int norm; /* TRUE if no swap, FALSE for byte swap */
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long x; /* 32-bit long to be byte swapped */
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{
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/* Possibly swap a 32-bit long between 8086 and 68000 byte order. */
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unsigned lo, hi;
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long l;
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if (norm) return(x); /* byte order was already ok */
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lo = conv2(FALSE, (int) x & 0xFFFF); /* low-order half, byte swapped */
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hi = conv2(FALSE, (int) (x>>16) & 0xFFFF); /* high-order half, swapped */
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l = ( (long) lo <<16) | hi;
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return(l);
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}
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/*===========================================================================*
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* clock_time *
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*===========================================================================*/
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time_t clock_time()
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{
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/* This routine returns the time in seconds since 1.1.1970. MINIX is an
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* astrophysically naive system that assumes the earth rotates at a constant
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* rate and that such things as leap seconds do not exist.
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*/
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register int k;
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clock_t uptime;
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time_t boottime;
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if ( (k=getuptime2(&uptime, &boottime)) != OK)
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panic("clock_time: getuptme2 failed: %d", k);
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return( (time_t) (boottime + (uptime/sys_hz())));
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}
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/*===========================================================================*
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* mfs_min *
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*===========================================================================*/
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int min(unsigned int l, unsigned int r)
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{
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if(r >= l) return(l);
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return(r);
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}
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/*===========================================================================*
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* mfs_nul *
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*===========================================================================*/
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void mfs_nul_f(char *file, int line, char *str, unsigned int len,
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unsigned int maxlen)
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{
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if(len < maxlen && str[len-1] != '\0') {
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printf("ext2 %s:%d string (length %d, maxlen %d) not null-terminated\n",
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file, line, len, maxlen);
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}
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}
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#define MYASSERT(c) if(!(c)) { printf("ext2:%s:%d: sanity check: %s failed\n", \
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file, line, #c); panic("sanity check " #c " failed: %d", __LINE__); }
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/*===========================================================================*
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* sanity_check *
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*===========================================================================*/
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void sanitycheck(char *file, int line)
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{
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MYASSERT(SELF_E > 0);
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if(superblock->s_dev != NO_DEV) {
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MYASSERT(superblock->s_dev == fs_dev);
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MYASSERT(superblock->s_block_size == lmfs_fs_block_size());
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} else {
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MYASSERT(_MIN_BLOCK_SIZE == lmfs_fs_block_size());
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}
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}
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/*===========================================================================*
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* ansi_strcmp *
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*===========================================================================*/
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int ansi_strcmp(register const char* ansi_s, register const char *s2,
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register size_t ansi_s_length)
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{
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/* Compare non null-terminated string ansi_s (length=ansi_s_length)
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* with C-string s2.
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* It returns 0 if strings are equal, otherwise -1 is returned.
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*/
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if (ansi_s_length) {
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do {
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if (*s2 == '\0')
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return -1;
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if (*ansi_s++ != *s2++)
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return -1;
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} while (--ansi_s_length > 0);
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if (*s2 == '\0')
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return 0;
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else
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return -1;
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}
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return 0;
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}
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/*===========================================================================*
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* setbit *
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*===========================================================================*/
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bit_t setbit(bitchunk_t *bitmap, bit_t max_bits, unsigned int word)
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{
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/* Find free bit in bitmap and set. Return number of the bit,
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* if failed return -1.
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*/
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bitchunk_t *wptr, *wlim;
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bit_t b = -1;
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/* TODO: do we need to add 1? I saw a situation, when it was
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* required, and since we check bit number with max_bits it
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* should be safe.
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*/
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wlim = &bitmap[FS_BITMAP_CHUNKS(max_bits >> 3)];
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/* Iterate over the words in block. */
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for (wptr = &bitmap[word]; wptr < wlim; wptr++) {
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bit_t i;
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bitchunk_t k;
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/* Does this word contain a free bit? */
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if (*wptr == (bitchunk_t) ~0)
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continue;
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/* Find and allocate the free bit. */
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k = (int) *wptr;
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for (i = 0; (k & (1 << i)) != 0; ++i) {}
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/* Bit number from the start of the bit map. */
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b = (wptr - &bitmap[0]) * FS_BITCHUNK_BITS + i;
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/* Don't allocate bits beyond the end of the map. */
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if (b >= max_bits) {
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b = -1;
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continue;
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}
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/* Allocate bit number. */
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k |= 1 << i;
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*wptr = (int) k;
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break;
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}
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return b;
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}
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/*===========================================================================*
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* setbyte *
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*===========================================================================*/
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bit_t setbyte(bitchunk_t *bitmap, bit_t max_bits)
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{
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/* Find free byte in bitmap and set it. Return number of the starting bit,
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* if failed return -1.
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*/
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unsigned char *wptr, *wlim;
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bit_t b = -1;
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wptr = (unsigned char*) &bitmap[0];
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/* TODO: do we need to add 1? I saw a situation, when it was
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* required, and since we check bit number with max_bits it
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* should be safe.
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*/
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wlim = &wptr[(max_bits >> 3)];
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/* Iterate over the words in block. */
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for ( ; wptr < wlim; wptr++) {
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/* Is it a free byte? */
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if (*wptr | 0)
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continue;
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/* Bit number from the start of the bit map. */
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b = (wptr - (unsigned char*) &bitmap[0]) * CHAR_BIT;
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/* Don't allocate bits beyond the end of the map. */
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if (b + CHAR_BIT >= max_bits) {
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b = -1;
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continue;
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}
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/* Allocate byte number. */
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*wptr = (unsigned char) ~0;
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break;
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}
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return b;
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}
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/*===========================================================================*
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* unsetbit *
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*===========================================================================*/
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int unsetbit(bitchunk_t *bitmap, bit_t bit)
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{
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/* Unset specified bit. If requested bit is already free return -1,
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* otherwise return 0.
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*/
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unsigned int word; /* bit_returned word in bitmap */
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bitchunk_t k, mask;
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word = bit / FS_BITCHUNK_BITS;
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bit = bit % FS_BITCHUNK_BITS; /* index in word */
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mask = 1 << bit;
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k = (int) bitmap[word];
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if (!(k & mask))
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return -1;
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k &= ~mask;
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bitmap[word] = (int) k;
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return 0;
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}
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