patch-2.1.112 linux/fs/ufs/cylinder.c

• Lines: 213
• Date: Sun Jul 26 01:20:22 1998
• Orig file: v2.1.111/linux/fs/ufs/cylinder.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.111/linux/fs/ufs/cylinder.c linux/fs/ufs/cylinder.c
@@ -0,0 +1,212 @@
+/*
+ *  linux/fs/ufs/cylinder.c
+ *
+ * Copyright (C) 1998
+ * Daniel Pirkl <daniel.pirkl@email.cz>
+ * Charles University, Faculty of Mathematics and Physics
+ *
+ *  ext2 - inode (block) bitmap caching inspired
+ */
+
+#include <linux/fs.h>
+#include <linux/ufs_fs.h>
+#include <linux/sched.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/locks.h>
+
+#include <asm/bitops.h>
+#include <asm/byteorder.h>
+
+#include "swab.h"
+#include "util.h"
+
+#undef UFS_CYLINDER_DEBUG
+#undef UFS_CYLINDER_DEBUG_MORE
+
+#ifdef UFS_CYLINDER_DEBUG
+#define UFSD(x) printk("(%s, %d), %s:", __FILE__, __LINE__, __FUNCTION__); printk x;
+#else
+#define UFSD(x)
+#endif
+
+
+/*
+ * Read cylinder group into cache. The memory space for ufs_cg_private_info
+ * structure is already allocated during ufs_read_super.
+ */
+static void ufs_read_cylinder (struct super_block * sb,
+	unsigned cgno, unsigned bitmap_nr)
+{
+	struct ufs_sb_private_info * uspi;
+	struct ufs_cg_private_info * ucpi;
+	struct ufs_cylinder_group * ucg;
+	unsigned i, j;
+	unsigned swab;
+
+	UFSD(("ENTER, cgno %u, bitmap_nr %u\n", cgno, bitmap_nr))
+	swab = sb->u.ufs_sb.s_swab;	
+	uspi = sb->u.ufs_sb.s_uspi;
+	ucpi = sb->u.ufs_sb.s_ucpi[bitmap_nr];
+	ucg = (struct ufs_cylinder_group *)sb->u.ufs_sb.s_ucg[cgno]->b_data;
+
+#ifdef UFS_CYLINDER_DEBUG_MORE
+	ufs_print_cylinder_stuff (ucg, swab);
+#endif
+
+	UCPI_UBH->fragment = ufs_cgcmin(cgno);
+	UCPI_UBH->count = uspi->s_cgsize >> sb->s_blocksize_bits;
+	/*
+	 * We have already the first fragment of cylinder group block in buffer
+	 */
+	UCPI_UBH->bh[0] = sb->u.ufs_sb.s_ucg[cgno];
+	for (i = 1; i < UCPI_UBH->count; i++)
+		if (!(UCPI_UBH->bh[i] = bread (sb->s_dev, UCPI_UBH->fragment + i, sb->s_blocksize)))
+			goto failed;
+	sb->u.ufs_sb.s_cgno[bitmap_nr] = cgno;
+			
+	ucpi->c_cgx = SWAB32(ucg->cg_cgx);
+	ucpi->c_ncyl = SWAB16(ucg->cg_ncyl);
+	ucpi->c_niblk = SWAB16(ucg->cg_niblk);
+	ucpi->c_ndblk = SWAB32(ucg->cg_ndblk);
+	ucpi->c_rotor = SWAB32(ucg->cg_rotor);
+	ucpi->c_frotor = SWAB32(ucg->cg_frotor);
+	ucpi->c_irotor = SWAB32(ucg->cg_irotor);
+	ucpi->c_btotoff = SWAB32(ucg->cg_btotoff);
+	ucpi->c_boff = SWAB32(ucg->cg_boff);
+	ucpi->c_iusedoff = SWAB32(ucg->cg_iusedoff);
+	ucpi->c_freeoff = SWAB32(ucg->cg_freeoff);
+	ucpi->c_nextfreeoff = SWAB32(ucg->cg_nextfreeoff);
+	
+	UFSD(("EXIT\n"))
+	return;	
+	
+failed:
+	for (j = 1; j < i; j++)
+		brelse (sb->u.ufs_sb.s_ucg[j]);
+	sb->u.ufs_sb.s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
+	ufs_error (sb, "ufs_read_cylinder", "can't read cylinder group block %u", cgno);
+}
+
+/*
+ * Remove cylinder group from cache, does'n release memory
+ * allocated for cylinder group (this is done at ufs_put_super only).
+ */
+void ufs_put_cylinder (struct super_block * sb, unsigned bitmap_nr)
+{
+	struct ufs_sb_private_info * uspi; 
+	struct ufs_cg_private_info * ucpi;
+	struct ufs_cylinder_group * ucg;
+	unsigned i;
+	unsigned swab;
+
+	UFSD(("ENTER, bitmap_nr %u\n", bitmap_nr))
+
+	swab = sb->u.ufs_sb.s_swab;
+	uspi = sb->u.ufs_sb.s_uspi;
+	if (sb->u.ufs_sb.s_cgno[bitmap_nr] == UFS_CGNO_EMPTY) {
+		UFSD(("EXIT\n"))
+		return;
+	}
+	ucpi = sb->u.ufs_sb.s_ucpi[bitmap_nr];
+	ucg = ubh_get_ucg(UCPI_UBH);
+
+	if (uspi->s_ncg > UFS_MAX_GROUP_LOADED && bitmap_nr >= sb->u.ufs_sb.s_cg_loaded) {
+		ufs_panic (sb, "ufs_put_cylinder", "internal error");
+		return;
+	}
+	/*
+	 * rotor is not so important data, so we put it to disk 
+	 * at the end of working with cylinder
+	 */
+	ucg->cg_rotor = SWAB32(ucpi->c_rotor);
+	ucg->cg_frotor = SWAB32(ucpi->c_frotor);
+	ucg->cg_irotor = SWAB32(ucpi->c_irotor);
+	ubh_mark_buffer_dirty (UCPI_UBH, 1);
+	for (i = 1; i < UCPI_UBH->count; i++) {
+		brelse (UCPI_UBH->bh[i]);
+	}
+
+	sb->u.ufs_sb.s_cgno[bitmap_nr] = UFS_CGNO_EMPTY;
+	UFSD(("EXIT\n"))
+}
+
+/*
+ * Find cylinder group in cache and return it as pointer.
+ * If cylinder group is not in cache, we will load it from disk.
+ *
+ * The cache is managed by LRU alghoritm. 
+ */
+struct ufs_cg_private_info * ufs_load_cylinder (
+	struct super_block * sb, unsigned cgno)
+{
+	struct ufs_sb_private_info * uspi;
+	struct ufs_cg_private_info * ucpi;
+	unsigned cg, i, j;
+
+	UFSD(("ENTER, cgno %u\n", cgno))
+
+	uspi = sb->u.ufs_sb.s_uspi;
+	if (cgno >= uspi->s_ncg) {
+		ufs_panic (sb, "ufs_load_cylinder", "internal error, high number of cg");
+		return NULL;
+	}
+	/*
+	 * Cylinder group number cg it in cache and it was last used
+	 */
+	if (sb->u.ufs_sb.s_cgno[0] == cgno) {
+		UFSD(("EXIT\n"))
+		return sb->u.ufs_sb.s_ucpi[0];
+	}
+	/*
+	 * Number of cylinder groups is not higher than UFS_MAX_GROUP_LOADED
+	 */
+	if (uspi->s_ncg <= UFS_MAX_GROUP_LOADED) {
+		if (sb->u.ufs_sb.s_cgno[cgno] != UFS_CGNO_EMPTY) {
+			if (sb->u.ufs_sb.s_cgno[cgno] != cgno) {
+				ufs_panic (sb, "ufs_load_cylinder", "internal error, wrog number of cg in cache");
+				UFSD(("EXIT (FAILED)\n"))
+				return NULL;
+			}
+			else {
+				UFSD(("EXIT\n"))
+				return sb->u.ufs_sb.s_ucpi[cgno];
+			}
+		} else {
+			ufs_read_cylinder (sb, cgno, cgno);
+			UFSD(("EXIT\n"))
+			return sb->u.ufs_sb.s_ucpi[cgno];
+		}
+	}
+	/*
+	 * Cylinder group number cg is in cache but it was not last used, 
+	 * we will move to the first position
+	 */
+	for (i = 0; i < sb->u.ufs_sb.s_cg_loaded && sb->u.ufs_sb.s_cgno[i] != cgno; i++);
+	if (i < sb->u.ufs_sb.s_cg_loaded && sb->u.ufs_sb.s_cgno[i] == cgno) {
+		cg = sb->u.ufs_sb.s_cgno[i];
+		ucpi = sb->u.ufs_sb.s_ucpi[i];
+		for (j = i; j > 0; j--) {
+			sb->u.ufs_sb.s_cgno[j] = sb->u.ufs_sb.s_cgno[j-1];
+			sb->u.ufs_sb.s_ucpi[j] = sb->u.ufs_sb.s_ucpi[j-1];
+		}
+		sb->u.ufs_sb.s_cgno[0] = cg;
+		sb->u.ufs_sb.s_ucpi[0] = ucpi;
+	/*
+	 * Cylinder group number cg is not in cache, we will read it from disk
+	 * and put it to the first possition
+	 */
+	} else {
+		if (sb->u.ufs_sb.s_cg_loaded < UFS_MAX_GROUP_LOADED)
+			sb->u.ufs_sb.s_cg_loaded++;
+		else
+			ufs_put_cylinder (sb, UFS_MAX_GROUP_LOADED-1);
+		for (j = sb->u.ufs_sb.s_cg_loaded - 1; j > 0; j--) {
+			sb->u.ufs_sb.s_cgno[j] = sb->u.ufs_sb.s_cgno[j-1];
+			sb->u.ufs_sb.s_ucpi[j] = sb->u.ufs_sb.s_ucpi[j-1];
+		}
+		ufs_read_cylinder (sb, cgno, 0);
+	}
+	UFSD(("EXIT\n"))
+	return sb->u.ufs_sb.s_ucpi[0];
+}