6c46a77d95
- The lmfs_get_block*(3) API calls may now return an error. The idea is to encourage a next generation of file system services to do a better job at dealing with block read errors than the MFS-derived implementations do. These existing file systems have been changed to panic immediately upon getting a block read error, in order to let unchecked errors cause corruption. Note that libbdev already retries failing I/O operations a few times first. - The libminixfs block device I/O module (bio.c) now deals properly with end-of-file conditions on block devices. Since a device or partition size may not be a multiple of the root file system's block size, support for partial block retrival has been added, with a new internal lmfs_get_partial_block(3) call. A new test program, test85, tests the new handling of EOF conditions when reading, writing, and memory-mapping a block device. Change-Id: I05e35b6b8851488328a2679da635ebba0c6d08ce
97 lines
1.9 KiB
C
97 lines
1.9 KiB
C
#include "inc.h"
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static struct dir_extent dir_extents[NR_DIR_EXTENT_RECORDS];
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struct dir_extent* alloc_extent(void)
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{
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/* Return a free extent from the pool. */
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int i;
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struct dir_extent *extent;
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for (i = 0; i < NR_DIR_EXTENT_RECORDS; i++) {
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extent = &dir_extents[i];
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if (extent->in_use == 0) {
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memset(extent, 0, sizeof(*extent));
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extent->in_use = 1;
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return extent;
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}
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}
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panic("No free extents in cache");
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}
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void free_extent(struct dir_extent *e)
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{
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if (e == NULL)
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return;
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if (e->in_use == 0)
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panic("Trying to free unused extent");
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free_extent(e->next);
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e->in_use = 0;
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}
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struct buf* read_extent_block(struct dir_extent *e, size_t block)
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{
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struct buf *bp;
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size_t block_id;
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int r;
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block_id = get_extent_absolute_block_id(e, block);
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if (block_id == 0 || block_id >= v_pri.volume_space_size_l)
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return NULL;
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/* Not all callers deal well with failure, so panic on I/O error. */
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if ((r = lmfs_get_block(&bp, fs_dev, block_id, NORMAL)) != OK)
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panic("ISOFS: error getting block (%llu,%zu): %d",
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fs_dev, block_id, r);
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return bp;
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}
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size_t get_extent_absolute_block_id(struct dir_extent *e, size_t block)
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{
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size_t extent_offset = 0;
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if (e == NULL)
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return 0;
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/* Retrieve the extent on which the block lies. */
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while(block > extent_offset + e->length) {
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if (e->next == NULL)
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return 0;
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extent_offset += e->length;
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e = e->next;
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}
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return e->location + block - extent_offset;
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}
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time_t date7_to_time_t(const u8_t *date)
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{
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/* This function converts from the ISO 9660 7-byte time format to a
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* time_t.
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*/
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struct tm ltime;
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signed char time_zone = (signed char)date[6];
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ltime.tm_year = date[0];
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ltime.tm_mon = date[1] - 1;
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ltime.tm_mday = date[2];
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ltime.tm_hour = date[3];
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ltime.tm_min = date[4];
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ltime.tm_sec = date[5];
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ltime.tm_isdst = 0;
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/* Offset from Greenwich Mean Time */
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if (time_zone >= -52 && time_zone <= 52)
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ltime.tm_hour += time_zone;
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return mktime(<ime);
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}
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