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-rw-r--r--fs/fat/misc.c225
1 files changed, 225 insertions, 0 deletions
diff --git a/fs/fat/misc.c b/fs/fat/misc.c
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index 0000000..2a0df21
--- /dev/null
+++ b/fs/fat/misc.c
@@ -0,0 +1,225 @@
+/*
+ * linux/fs/fat/misc.c
+ *
+ * Written 1992,1993 by Werner Almesberger
+ * 22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980
+ * and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru)
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/msdos_fs.h>
+#include <linux/buffer_head.h>
+
+/*
+ * fat_fs_panic reports a severe file system problem and sets the file system
+ * read-only. The file system can be made writable again by remounting it.
+ */
+void fat_fs_panic(struct super_block *s, const char *fmt, ...)
+{
+ va_list args;
+
+ printk(KERN_ERR "FAT: Filesystem panic (dev %s)\n", s->s_id);
+
+ printk(KERN_ERR " ");
+ va_start(args, fmt);
+ vprintk(fmt, args);
+ va_end(args);
+ printk("\n");
+
+ if (!(s->s_flags & MS_RDONLY)) {
+ s->s_flags |= MS_RDONLY;
+ printk(KERN_ERR " File system has been set read-only\n");
+ }
+}
+
+EXPORT_SYMBOL(fat_fs_panic);
+
+/* Flushes the number of free clusters on FAT32 */
+/* XXX: Need to write one per FSINFO block. Currently only writes 1 */
+void fat_clusters_flush(struct super_block *sb)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct buffer_head *bh;
+ struct fat_boot_fsinfo *fsinfo;
+
+ if (sbi->fat_bits != 32)
+ return;
+
+ bh = sb_bread(sb, sbi->fsinfo_sector);
+ if (bh == NULL) {
+ printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n");
+ return;
+ }
+
+ fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
+ /* Sanity check */
+ if (!IS_FSINFO(fsinfo)) {
+ printk(KERN_ERR "FAT: Did not find valid FSINFO signature.\n"
+ " Found signature1 0x%08x signature2 0x%08x"
+ " (sector = %lu)\n",
+ le32_to_cpu(fsinfo->signature1),
+ le32_to_cpu(fsinfo->signature2),
+ sbi->fsinfo_sector);
+ } else {
+ if (sbi->free_clusters != -1)
+ fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
+ if (sbi->prev_free != -1)
+ fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
+ mark_buffer_dirty(bh);
+ if (sb->s_flags & MS_SYNCHRONOUS)
+ sync_dirty_buffer(bh);
+ }
+ brelse(bh);
+}
+
+/*
+ * fat_chain_add() adds a new cluster to the chain of clusters represented
+ * by inode.
+ */
+int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int ret, new_fclus, last;
+
+ /*
+ * We must locate the last cluster of the file to add this new
+ * one (new_dclus) to the end of the link list (the FAT).
+ */
+ last = new_fclus = 0;
+ if (MSDOS_I(inode)->i_start) {
+ int fclus, dclus;
+
+ ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
+ if (ret < 0)
+ return ret;
+ new_fclus = fclus + 1;
+ last = dclus;
+ }
+
+ /* add new one to the last of the cluster chain */
+ if (last) {
+ struct fat_entry fatent;
+
+ fatent_init(&fatent);
+ ret = fat_ent_read(inode, &fatent, last);
+ if (ret >= 0) {
+ int wait = inode_needs_sync(inode);
+ ret = fat_ent_write(inode, &fatent, new_dclus, wait);
+ fatent_brelse(&fatent);
+ }
+ if (ret < 0)
+ return ret;
+// fat_cache_add(inode, new_fclus, new_dclus);
+ } else {
+ MSDOS_I(inode)->i_start = new_dclus;
+ MSDOS_I(inode)->i_logstart = new_dclus;
+ /*
+ * Since generic_osync_inode() synchronize later if
+ * this is not directory, we don't here.
+ */
+ if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
+ ret = fat_sync_inode(inode);
+ if (ret)
+ return ret;
+ } else
+ mark_inode_dirty(inode);
+ }
+ if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
+ fat_fs_panic(sb, "clusters badly computed (%d != %lu)",
+ new_fclus, inode->i_blocks >> (sbi->cluster_bits - 9));
+ fat_cache_inval_inode(inode);
+ }
+ inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
+
+ return 0;
+}
+
+extern struct timezone sys_tz;
+
+/* Linear day numbers of the respective 1sts in non-leap years. */
+static int day_n[] = {
+ /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
+ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 0
+};
+
+/* Convert a MS-DOS time/date pair to a UNIX date (seconds since 1 1 70). */
+int date_dos2unix(unsigned short time, unsigned short date)
+{
+ int month, year, secs;
+
+ /*
+ * first subtract and mask after that... Otherwise, if
+ * date == 0, bad things happen
+ */
+ month = ((date >> 5) - 1) & 15;
+ year = date >> 9;
+ secs = (time & 31)*2+60*((time >> 5) & 63)+(time >> 11)*3600+86400*
+ ((date & 31)-1+day_n[month]+(year/4)+year*365-((year & 3) == 0 &&
+ month < 2 ? 1 : 0)+3653);
+ /* days since 1.1.70 plus 80's leap day */
+ secs += sys_tz.tz_minuteswest*60;
+ return secs;
+}
+
+/* Convert linear UNIX date to a MS-DOS time/date pair. */
+void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date)
+{
+ int day, year, nl_day, month;
+
+ unix_date -= sys_tz.tz_minuteswest*60;
+
+ /* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
+ if (unix_date < 315532800)
+ unix_date = 315532800;
+
+ *time = cpu_to_le16((unix_date % 60)/2+(((unix_date/60) % 60) << 5)+
+ (((unix_date/3600) % 24) << 11));
+ day = unix_date/86400-3652;
+ year = day/365;
+ if ((year+3)/4+365*year > day)
+ year--;
+ day -= (year+3)/4+365*year;
+ if (day == 59 && !(year & 3)) {
+ nl_day = day;
+ month = 2;
+ } else {
+ nl_day = (year & 3) || day <= 59 ? day : day-1;
+ for (month = 0; month < 12; month++) {
+ if (day_n[month] > nl_day)
+ break;
+ }
+ }
+ *date = cpu_to_le16(nl_day-day_n[month-1]+1+(month << 5)+(year << 9));
+}
+
+EXPORT_SYMBOL(fat_date_unix2dos);
+
+int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
+{
+ int i, e, err = 0;
+
+ for (i = 0; i < nr_bhs; i++) {
+ lock_buffer(bhs[i]);
+ if (test_clear_buffer_dirty(bhs[i])) {
+ get_bh(bhs[i]);
+ bhs[i]->b_end_io = end_buffer_write_sync;
+ e = submit_bh(WRITE, bhs[i]);
+ if (!err && e)
+ err = e;
+ } else
+ unlock_buffer(bhs[i]);
+ }
+ for (i = 0; i < nr_bhs; i++) {
+ wait_on_buffer(bhs[i]);
+ if (buffer_eopnotsupp(bhs[i])) {
+ clear_buffer_eopnotsupp(bhs[i]);
+ err = -EOPNOTSUPP;
+ } else if (!err && !buffer_uptodate(bhs[i]))
+ err = -EIO;
+ }
+ return err;
+}
+
+EXPORT_SYMBOL(fat_sync_bhs);
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