1 files changed, 582 insertions, 0 deletions

diff --git a/sys/gnu/fs/ext2fs/ext2_linux_balloc.c b/sys/gnu/fs/ext2fs/ext2_linux_balloc.c
new file mode 100644
index 0000000..25b9891
--- /dev/null
+++ b/sys/gnu/fs/ext2fs/ext2_linux_balloc.c
@@ -0,0 +1,582 @@
+/*
+ *  modified for Lites 1.1
+ *
+ *  Aug 1995, Godmar Back (gback@cs.utah.edu)
+ *  University of Utah, Department of Computer Science
+ */
+/*
+ *  linux/fs/ext2/balloc.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  Enhanced block allocation by Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
+ */
+
+/*
+ * The free blocks are managed by bitmaps.  A file system contains several
+ * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
+ * block for inodes, N blocks for the inode table and data blocks.
+ *
+ * The file system contains group descriptors which are located after the
+ * super block.  Each descriptor contains the number of the bitmap block and
+ * the free blocks count in the block.  The descriptors are loaded in memory
+ * when a file system is mounted (see ext2_read_super).
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/buf.h>
+#include <sys/proc.h>
+#include <sys/mount.h>
+#include <sys/vnode.h>
+
+#include <ufs/ufs/quota.h>
+#include <ufs/ufs/ufsmount.h>
+#include <gnu/ext2fs/ext2_extern.h>
+#include <gnu/ext2fs/ext2_fs.h>
+#include <gnu/ext2fs/ext2_fs_sb.h>
+#include <gnu/ext2fs/fs.h>
+#include <sys/stat.h>
+
+#ifdef i386
+#include <gnu/ext2fs/i386-bitops.h>
+#else
+#error Provide an bitops.h file, please !
+#endif
+
+unsigned long ext2_count_free __P((struct buffer_head *, unsigned int));
+
+#define in_range(b, first, len)		((b) >= (first) && (b) <= (first) + (len) - 1)
+
+/* got rid of get_group_desc since it can already be found in 
+ * ext2_linux_ialloc.c
+ */
+
+static void read_block_bitmap (struct mount * mp,
+			       unsigned int block_group,
+			       unsigned long bitmap_nr)
+{
+	struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
+	struct ext2_group_desc * gdp;
+	struct buffer_head * bh;
+	int    error;
+	
+	gdp = get_group_desc (mp, block_group, NULL);
+	if(error = bread (VFSTOUFS(mp)->um_devvp, 
+		fsbtodb(sb, gdp->bg_block_bitmap),sb->s_blocksize, NOCRED, &bh))
+		panic ( "read_block_bitmap: "
+			    "Cannot read block bitmap - "
+			    "block_group = %d, block_bitmap = %lu",
+			    block_group, (unsigned long) gdp->bg_block_bitmap);
+	sb->s_block_bitmap_number[bitmap_nr] = block_group;
+	sb->s_block_bitmap[bitmap_nr] = bh;
+}
+
+/*
+ * load_block_bitmap loads the block bitmap for a blocks group
+ *
+ * It maintains a cache for the last bitmaps loaded.  This cache is managed
+ * with a LRU algorithm.
+ *
+ * Notes:
+ * 1/ There is one cache per mounted file system.
+ * 2/ If the file system contains less than EXT2_MAX_GROUP_LOADED groups,
+ *    this function reads the bitmap without maintaining a LRU cache.
+ */
+static int load__block_bitmap (struct mount * mp,
+			       unsigned int block_group)
+{
+	int i, j;
+	struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
+	unsigned long block_bitmap_number;
+	struct buffer_head * block_bitmap;
+	int error;
+
+	if (block_group >= sb->s_groups_count)
+		panic ( "load_block_bitmap: "
+			    "block_group >= groups_count - "
+			    "block_group = %d, groups_count = %lu",
+			    block_group, sb->s_groups_count);
+
+	if (sb->s_groups_count <= EXT2_MAX_GROUP_LOADED) {
+		if (sb->s_block_bitmap[block_group]) {
+			if (sb->s_block_bitmap_number[block_group] !=
+			    block_group)
+				panic ( "load_block_bitmap: "
+					    "block_group != block_bitmap_number");
+			else
+				return block_group;
+		} else {
+			read_block_bitmap (mp, block_group, block_group);
+			return block_group;
+		}
+	}
+
+	for (i = 0; i < sb->s_loaded_block_bitmaps &&
+		    sb->s_block_bitmap_number[i] != block_group; i++)
+		;
+	if (i < sb->s_loaded_block_bitmaps &&
+  	    sb->s_block_bitmap_number[i] == block_group) {
+		block_bitmap_number = sb->s_block_bitmap_number[i];
+		block_bitmap = sb->s_block_bitmap[i];
+		for (j = i; j > 0; j--) {
+			sb->s_block_bitmap_number[j] =
+				sb->s_block_bitmap_number[j - 1];
+			sb->s_block_bitmap[j] =
+				sb->s_block_bitmap[j - 1];
+		}
+		sb->s_block_bitmap_number[0] = block_bitmap_number;
+		sb->s_block_bitmap[0] = block_bitmap;
+	} else {
+		if (sb->s_loaded_block_bitmaps < EXT2_MAX_GROUP_LOADED)
+			sb->s_loaded_block_bitmaps++;
+		else
+			brelse (sb->s_block_bitmap[EXT2_MAX_GROUP_LOADED - 1]);
+		for (j = sb->s_loaded_block_bitmaps - 1; j > 0;  j--) {
+			sb->s_block_bitmap_number[j] =
+				sb->s_block_bitmap_number[j - 1];
+			sb->s_block_bitmap[j] =
+				sb->s_block_bitmap[j - 1];
+		}
+		read_block_bitmap (mp, block_group, 0);
+	}
+	return 0;
+}
+
+static inline int load_block_bitmap (struct mount * mp,
+				     unsigned int block_group)
+{
+	struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
+	if (sb->s_loaded_block_bitmaps > 0 &&
+	    sb->s_block_bitmap_number[0] == block_group)
+		return 0;
+	
+	if (sb->s_groups_count <= EXT2_MAX_GROUP_LOADED && 
+	    sb->s_block_bitmap_number[block_group] == block_group &&
+	    sb->s_block_bitmap[block_group]) 
+		return block_group;
+
+	return load__block_bitmap (mp, block_group);
+}
+
+void ext2_free_blocks (struct mount * mp, unsigned long block,
+		       unsigned long count)
+{
+	struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
+	struct buffer_head * bh;
+	struct buffer_head * bh2;
+	unsigned long block_group;
+	unsigned long bit;
+	unsigned long i;
+	int bitmap_nr;
+	struct ext2_group_desc * gdp;
+	struct ext2_super_block * es = sb->s_es;
+
+	if (!sb) {
+		printf ("ext2_free_blocks: nonexistent device");
+		return;
+	}
+	lock_super (VFSTOUFS(mp)->um_devvp);
+	if (block < es->s_first_data_block || 
+	    (block + count) > es->s_blocks_count) {
+		printf ( "ext2_free_blocks: "
+			    "Freeing blocks not in datazone - "
+			    "block = %lu, count = %lu", block, count);
+		unlock_super (VFSTOUFS(mp)->um_devvp);
+		return;
+	}
+
+	ext2_debug ("freeing blocks %lu to %lu\n", block, block+count-1);
+
+	block_group = (block - es->s_first_data_block) /
+		      EXT2_BLOCKS_PER_GROUP(sb);
+	bit = (block - es->s_first_data_block) % EXT2_BLOCKS_PER_GROUP(sb);
+	if (bit + count > EXT2_BLOCKS_PER_GROUP(sb))
+		panic ( "ext2_free_blocks: "
+			    "Freeing blocks across group boundary - "
+			    "Block = %lu, count = %lu",
+			    block, count);
+	bitmap_nr = load_block_bitmap (mp, block_group);
+	bh = sb->s_block_bitmap[bitmap_nr];
+	gdp = get_group_desc (mp, block_group, &bh2);
+
+	if (/* test_opt (sb, CHECK_STRICT) && 	assume always strict ! */
+	    (in_range (gdp->bg_block_bitmap, block, count) ||
+	     in_range (gdp->bg_inode_bitmap, block, count) ||
+	     in_range (block, gdp->bg_inode_table,
+		       sb->s_itb_per_group) ||
+	     in_range (block + count - 1, gdp->bg_inode_table,
+		       sb->s_itb_per_group)))
+		panic ( "ext2_free_blocks: "
+			    "Freeing blocks in system zones - "
+			    "Block = %lu, count = %lu",
+			    block, count);
+
+	for (i = 0; i < count; i++) {
+		if (!clear_bit (bit + i, bh->b_data))
+			printf ("ext2_free_blocks: "
+				      "bit already cleared for block %lu", 
+				      block);
+		else {
+			gdp->bg_free_blocks_count++;
+			es->s_free_blocks_count++;
+		}
+	}
+
+	mark_buffer_dirty(bh2);
+	mark_buffer_dirty(bh, 1);
+/****
+	if (sb->s_flags & MS_SYNCHRONOUS) {
+		ll_rw_block (WRITE, 1, &bh);
+		wait_on_buffer (bh);
+	}
+****/
+	sb->s_dirt = 1;
+	unlock_super (VFSTOUFS(mp)->um_devvp);
+	return;
+}
+
+/*
+ * ext2_new_block uses a goal block to assist allocation.  If the goal is
+ * free, or there is a free block within 32 blocks of the goal, that block
+ * is allocated.  Otherwise a forward search is made for a free block; within 
+ * each block group the search first looks for an entire free byte in the block
+ * bitmap, and then for any free bit if that fails.
+ */
+int ext2_new_block (struct mount * mp, unsigned long goal,
+		    long * prealloc_count,
+		    long * prealloc_block)
+{
+	struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
+	struct buffer_head * bh;
+	struct buffer_head * bh2;
+	char * p, * r;
+	int i, j, k, tmp;
+	int bitmap_nr;
+	struct ext2_group_desc * gdp;
+	struct ext2_super_block * es = sb->s_es;
+
+#ifdef EXT2FS_DEBUG
+	static int goal_hits = 0, goal_attempts = 0;
+#endif
+	if (!sb) {
+		printf ("ext2_new_block: nonexistent device");
+		return 0;
+	}
+	lock_super (VFSTOUFS(mp)->um_devvp);
+
+        ext2_debug ("goal=%lu.\n", goal);
+
+repeat:
+	/*
+	 * First, test whether the goal block is free.
+	 */
+	if (goal < es->s_first_data_block || goal >= es->s_blocks_count)
+		goal = es->s_first_data_block;
+	i = (goal - es->s_first_data_block) / EXT2_BLOCKS_PER_GROUP(sb);
+	gdp = get_group_desc (mp, i, &bh2);
+	if (gdp->bg_free_blocks_count > 0) {
+		j = ((goal - es->s_first_data_block) % EXT2_BLOCKS_PER_GROUP(sb));
+#ifdef EXT2FS_DEBUG
+		if (j)
+			goal_attempts++;
+#endif
+		bitmap_nr = load_block_bitmap (mp, i);
+		bh = sb->s_block_bitmap[bitmap_nr];
+
+		ext2_debug ("goal is at %d:%d.\n", i, j); 
+
+		if (!test_bit(j, bh->b_data)) {
+#ifdef EXT2FS_DEBUG
+			goal_hits++;
+			ext2_debug ("goal bit allocated.\n");
+#endif
+			goto got_block;
+		}
+		if (j) {
+			/*
+			 * The goal was occupied; search forward for a free 
+			 * block within the next XX blocks.
+			 *
+			 * end_goal is more or less random, but it has to be
+			 * less than EXT2_BLOCKS_PER_GROUP. Aligning up to the
+			 * next 64-bit boundary is simple..
+			 */
+			int end_goal = (j + 63) & ~63;
+			j = find_next_zero_bit(bh->b_data, end_goal, j);
+			if (j < end_goal)
+				goto got_block;
+		}
+	
+		ext2_debug ("Bit not found near goal\n");
+
+		/*
+		 * There has been no free block found in the near vicinity
+		 * of the goal: do a search forward through the block groups,
+		 * searching in each group first for an entire free byte in
+		 * the bitmap and then for any free bit.
+		 * 
+		 * Search first in the remainder of the current group; then,
+		 * cyclicly search through the rest of the groups.
+		 */
+		p = ((char *) bh->b_data) + (j >> 3);
+		r = memscan(p, 0, (EXT2_BLOCKS_PER_GROUP(sb) - j + 7) >> 3);
+		k = (r - ((char *) bh->b_data)) << 3;
+		if (k < EXT2_BLOCKS_PER_GROUP(sb)) {
+			j = k;
+			goto search_back;
+		}
+		k = find_next_zero_bit ((unsigned long *) bh->b_data, 
+					EXT2_BLOCKS_PER_GROUP(sb),
+					j);
+		if (k < EXT2_BLOCKS_PER_GROUP(sb)) {
+			j = k;
+			goto got_block;
+		}
+	}
+
+	ext2_debug ("Bit not found in block group %d.\n", i); 
+
+	/*
+	 * Now search the rest of the groups.  We assume that 
+	 * i and gdp correctly point to the last group visited.
+	 */
+	for (k = 0; k < sb->s_groups_count; k++) {
+		i++;
+		if (i >= sb->s_groups_count)
+			i = 0;
+		gdp = get_group_desc (mp, i, &bh2);
+		if (gdp->bg_free_blocks_count > 0)
+			break;
+	}
+	if (k >= sb->s_groups_count) {
+		unlock_super (VFSTOUFS(mp)->um_devvp);
+		return 0;
+	}
+	bitmap_nr = load_block_bitmap (mp, i);
+	bh = sb->s_block_bitmap[bitmap_nr];
+	r = memscan(bh->b_data, 0, EXT2_BLOCKS_PER_GROUP(sb) >> 3);
+	j = (r - bh->b_data) << 3;
+
+	if (j < EXT2_BLOCKS_PER_GROUP(sb))
+		goto search_back;
+	else
+		j = find_first_zero_bit ((unsigned long *) bh->b_data,
+					 EXT2_BLOCKS_PER_GROUP(sb));
+	if (j >= EXT2_BLOCKS_PER_GROUP(sb)) {
+		printf ( "ext2_new_block: "
+			 "Free blocks count corrupted for block group %d", i);
+		unlock_super (VFSTOUFS(mp)->um_devvp);
+		return 0;
+	}
+
+search_back:
+	/* 
+	 * We have succeeded in finding a free byte in the block
+	 * bitmap.  Now search backwards up to 7 bits to find the
+	 * start of this group of free blocks.
+	 */
+	for (k = 0; k < 7 && j > 0 && !test_bit (j - 1, bh->b_data); k++, j--);
+	
+got_block:
+
+	ext2_debug ("using block group %d(%d)\n", i, gdp->bg_free_blocks_count);
+
+	tmp = j + i * EXT2_BLOCKS_PER_GROUP(sb) + es->s_first_data_block;
+
+	if (/* test_opt (sb, CHECK_STRICT) && we are always strict. */
+	    (tmp == gdp->bg_block_bitmap ||
+	     tmp == gdp->bg_inode_bitmap ||
+	     in_range (tmp, gdp->bg_inode_table, sb->s_itb_per_group)))
+		panic ( "ext2_new_block: "
+			    "Allocating block in system zone - "
+			    "%dth block = %u in group %u", j, tmp, i);
+
+	if (set_bit (j, bh->b_data)) {
+		printf ( "ext2_new_block: "
+			 "bit already set for block %d", j);
+		goto repeat;
+	}
+
+	ext2_debug ("found bit %d\n", j);
+
+	/*
+	 * Do block preallocation now if required.
+	 */
+#ifdef EXT2_PREALLOCATE
+	if (prealloc_block) {
+		*prealloc_count = 0;
+		*prealloc_block = tmp + 1;
+		for (k = 1;
+		     k < 8 && (j + k) < EXT2_BLOCKS_PER_GROUP(sb); k++) {
+			if (set_bit (j + k, bh->b_data))
+				break;
+			(*prealloc_count)++;
+		}	
+		gdp->bg_free_blocks_count -= *prealloc_count;
+		es->s_free_blocks_count -= *prealloc_count;
+		ext2_debug ("Preallocated a further %lu bits.\n",
+			    *prealloc_count); 
+	}
+#endif
+
+	j = tmp;
+
+	mark_buffer_dirty(bh);
+/****
+	if (sb->s_flags & MS_SYNCHRONOUS) {
+		ll_rw_block (WRITE, 1, &bh);
+		wait_on_buffer (bh);
+	}
+****/
+	if (j >= es->s_blocks_count) {
+		printf ( "ext2_new_block: "
+			    "block >= blocks count - "
+			    "block_group = %d, block=%d", i, j);
+		unlock_super (VFSTOUFS(mp)->um_devvp);
+		return 0;
+	}
+
+	ext2_debug ("allocating block %d. "
+		    "Goal hits %d of %d.\n", j, goal_hits, goal_attempts);
+
+	gdp->bg_free_blocks_count--;
+	mark_buffer_dirty(bh2, 1);
+	es->s_free_blocks_count--;
+	sb->s_dirt = 1;
+	unlock_super (VFSTOUFS(mp)->um_devvp);
+	return j;
+}
+
+unsigned long ext2_count_free_blocks (struct mount * mp)
+{
+	struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
+#ifdef EXT2FS_DEBUG
+	struct ext2_super_block * es;
+	unsigned long desc_count, bitmap_count, x;
+	int bitmap_nr;
+	struct ext2_group_desc * gdp;
+	int i;
+	
+	lock_super (VFSTOUFS(mp)->um_devvp);
+	es = sb->s_es;
+	desc_count = 0;
+	bitmap_count = 0;
+	gdp = NULL;
+	for (i = 0; i < sb->s_groups_count; i++) {
+		gdp = get_group_desc (mp, i, NULL);
+		desc_count += gdp->bg_free_blocks_count;
+		bitmap_nr = load_block_bitmap (mp, i);
+		x = ext2_count_free (sb->s_block_bitmap[bitmap_nr],
+				     sb->s_blocksize);
+		ext2_debug ("group %d: stored = %d, counted = %lu\n",
+			i, gdp->bg_free_blocks_count, x);
+		bitmap_count += x;
+	}
+	ext2_debug( "stored = %lu, computed = %lu, %lu\n",
+	       es->s_free_blocks_count, desc_count, bitmap_count);
+	unlock_super (VFSTOUFS(mp)->um_devvp);
+	return bitmap_count;
+#else
+	return sb->s_es->s_free_blocks_count;
+#endif
+}
+
+
+static inline int block_in_use (unsigned long block,
+				struct ext2_sb_info * sb,
+				unsigned char * map)
+{
+	return test_bit ((block - sb->s_es->s_first_data_block) %
+			 EXT2_BLOCKS_PER_GROUP(sb), map);
+}
+
+void ext2_check_blocks_bitmap (struct mount * mp)
+{
+	struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
+	struct buffer_head * bh;
+	struct ext2_super_block * es;
+	unsigned long desc_count, bitmap_count, x;
+	unsigned long desc_blocks;
+	int bitmap_nr;
+	struct ext2_group_desc * gdp;
+	int i, j;
+
+	lock_super (VFSTOUFS(mp)->um_devvp);
+	es = sb->s_es;
+	desc_count = 0;
+	bitmap_count = 0;
+	gdp = NULL;
+	desc_blocks = (sb->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
+		      EXT2_DESC_PER_BLOCK(sb);
+	for (i = 0; i < sb->s_groups_count; i++) {
+		gdp = get_group_desc (mp, i, NULL);
+		desc_count += gdp->bg_free_blocks_count;
+		bitmap_nr = load_block_bitmap (mp, i);
+		bh = sb->s_block_bitmap[bitmap_nr];
+
+		if (!test_bit (0, bh->b_data))
+			printf ( "ext2_check_blocks_bitmap: "
+				    "Superblock in group %d is marked free", i);
+
+		for (j = 0; j < desc_blocks; j++)
+			if (!test_bit (j + 1, bh->b_data))
+				printf ("ext2_check_blocks_bitmap: "
+					    "Descriptor block #%d in group "
+					    "%d is marked free", j, i);
+
+		if (!block_in_use (gdp->bg_block_bitmap, sb, bh->b_data))
+			printf ("ext2_check_blocks_bitmap: "
+				    "Block bitmap for group %d is marked free",
+				    i);
+
+		if (!block_in_use (gdp->bg_inode_bitmap, sb, bh->b_data))
+			printf ("ext2_check_blocks_bitmap: "
+				    "Inode bitmap for group %d is marked free",
+				    i);
+
+		for (j = 0; j < sb->s_itb_per_group; j++)
+			if (!block_in_use (gdp->bg_inode_table + j, sb, bh->b_data))
+				printf ("ext2_check_blocks_bitmap: "
+					    "Block #%d of the inode table in "
+					    "group %d is marked free", j, i);
+
+		x = ext2_count_free (bh, sb->s_blocksize);
+		if (gdp->bg_free_blocks_count != x)
+			printf ("ext2_check_blocks_bitmap: "
+				    "Wrong free blocks count for group %d, "
+				    "stored = %d, counted = %lu", i,
+				    gdp->bg_free_blocks_count, x);
+		bitmap_count += x;
+	}
+	if (es->s_free_blocks_count != bitmap_count)
+		printf ("ext2_check_blocks_bitmap: "
+			    "Wrong free blocks count in super block, "
+			    "stored = %lu, counted = %lu",
+			    (unsigned long) es->s_free_blocks_count, bitmap_count);
+	unlock_super (VFSTOUFS(mp)->um_devvp);
+}
+
+/*
+ *  this function is taken from 
+ *  linux/fs/ext2/bitmap.c
+ */
+
+static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
+
+unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars)
+{
+        unsigned int i;
+        unsigned long sum = 0;
+
+        if (!map)
+                return (0);
+        for (i = 0; i < numchars; i++)
+                sum += nibblemap[map->b_data[i] & 0xf] +
+                        nibblemap[(map->b_data[i] >> 4) & 0xf];
+        return (sum);
+}
+