Initial revision

1 files changed, 555 insertions, 0 deletions

diff --git a/ext2fs/ialloc.c b/ext2fs/ialloc.c
new file mode 100644
index 00000000..9102d02b
--- /dev/null
+++ b/ext2fs/ialloc.c
@@ -0,0 +1,555 @@
+/*
+ *  linux/fs/ext2/ialloc.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)
+ *
+ *  BSD ufs-inspired inode and directory allocation by 
+ *  Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
+ */
+
+/*
+ * ialloc.c contains the inodes allocation and deallocation routines
+ */
+
+/*
+ * The free inodes 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 <linux/fs.h>
+#include <linux/ext2_fs.h>
+#include <linux/sched.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/locks.h>
+
+#include <asm/bitops.h>
+
+static struct ext2_group_desc * get_group_desc (struct super_block * sb,
+						unsigned int block_group,
+						struct buffer_head ** bh)
+{
+	unsigned long group_desc;
+	unsigned long desc;
+	struct ext2_group_desc * gdp;
+
+	if (block_group >= sb->u.ext2_sb.s_groups_count)
+		ext2_panic (sb, "get_group_desc",
+			    "block_group >= groups_count - "
+			    "block_group = %d, groups_count = %lu",
+			    block_group, sb->u.ext2_sb.s_groups_count);
+
+	group_desc = block_group / EXT2_DESC_PER_BLOCK(sb);
+	desc = block_group % EXT2_DESC_PER_BLOCK(sb);
+	if (!sb->u.ext2_sb.s_group_desc[group_desc])
+		ext2_panic (sb, "get_group_desc",
+			    "Group descriptor not loaded - "
+			    "block_group = %d, group_desc = %lu, desc = %lu",
+			     block_group, group_desc, desc);
+	gdp = (struct ext2_group_desc *) 
+		sb->u.ext2_sb.s_group_desc[group_desc]->b_data;
+	if (bh)
+		*bh = sb->u.ext2_sb.s_group_desc[group_desc];
+	return gdp + desc;
+}
+
+static void read_inode_bitmap (struct super_block * sb,
+			       unsigned long block_group,
+			       unsigned int bitmap_nr)
+{
+	struct ext2_group_desc * gdp;
+	struct buffer_head * bh;
+
+	gdp = get_group_desc (sb, block_group, NULL);
+	bh = bread (sb->s_dev, gdp->bg_inode_bitmap, sb->s_blocksize);
+	if (!bh)
+		ext2_panic (sb, "read_inode_bitmap",
+			    "Cannot read inode bitmap - "
+			    "block_group = %lu, inode_bitmap = %lu",
+			    block_group, (unsigned long) gdp->bg_inode_bitmap);
+	sb->u.ext2_sb.s_inode_bitmap_number[bitmap_nr] = block_group;
+	sb->u.ext2_sb.s_inode_bitmap[bitmap_nr] = bh;
+}
+
+/*
+ * load_inode_bitmap loads the inode 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_inode_bitmap (struct super_block * sb,
+			      unsigned int block_group)
+{
+	int i, j;
+	unsigned long inode_bitmap_number;
+	struct buffer_head * inode_bitmap;
+
+	if (block_group >= sb->u.ext2_sb.s_groups_count)
+		ext2_panic (sb, "load_inode_bitmap",
+			    "block_group >= groups_count - "
+			    "block_group = %d, groups_count = %lu",
+			     block_group, sb->u.ext2_sb.s_groups_count);
+	if (sb->u.ext2_sb.s_loaded_inode_bitmaps > 0 &&
+	    sb->u.ext2_sb.s_inode_bitmap_number[0] == block_group)
+		return 0;
+	if (sb->u.ext2_sb.s_groups_count <= EXT2_MAX_GROUP_LOADED) {
+		if (sb->u.ext2_sb.s_inode_bitmap[block_group]) {
+			if (sb->u.ext2_sb.s_inode_bitmap_number[block_group] != block_group)
+				ext2_panic (sb, "load_inode_bitmap",
+					    "block_group != inode_bitmap_number");
+			else
+				return block_group;
+		} else {
+			read_inode_bitmap (sb, block_group, block_group);
+			return block_group;
+		}
+	}
+
+	for (i = 0; i < sb->u.ext2_sb.s_loaded_inode_bitmaps &&
+		    sb->u.ext2_sb.s_inode_bitmap_number[i] != block_group;
+	     i++)
+		;
+	if (i < sb->u.ext2_sb.s_loaded_inode_bitmaps &&
+  	    sb->u.ext2_sb.s_inode_bitmap_number[i] == block_group) {
+		inode_bitmap_number = sb->u.ext2_sb.s_inode_bitmap_number[i];
+		inode_bitmap = sb->u.ext2_sb.s_inode_bitmap[i];
+		for (j = i; j > 0; j--) {
+			sb->u.ext2_sb.s_inode_bitmap_number[j] =
+				sb->u.ext2_sb.s_inode_bitmap_number[j - 1];
+			sb->u.ext2_sb.s_inode_bitmap[j] =
+				sb->u.ext2_sb.s_inode_bitmap[j - 1];
+		}
+		sb->u.ext2_sb.s_inode_bitmap_number[0] = inode_bitmap_number;
+		sb->u.ext2_sb.s_inode_bitmap[0] = inode_bitmap;
+	} else {
+		if (sb->u.ext2_sb.s_loaded_inode_bitmaps < EXT2_MAX_GROUP_LOADED)
+			sb->u.ext2_sb.s_loaded_inode_bitmaps++;
+		else
+			brelse (sb->u.ext2_sb.s_inode_bitmap[EXT2_MAX_GROUP_LOADED - 1]);
+		for (j = sb->u.ext2_sb.s_loaded_inode_bitmaps - 1; j > 0; j--) {
+			sb->u.ext2_sb.s_inode_bitmap_number[j] =
+				sb->u.ext2_sb.s_inode_bitmap_number[j - 1];
+			sb->u.ext2_sb.s_inode_bitmap[j] =
+				sb->u.ext2_sb.s_inode_bitmap[j - 1];
+		}
+		read_inode_bitmap (sb, block_group, 0);
+	}
+	return 0;
+}
+
+/*
+ * This function sets the deletion time for the inode
+ *
+ * This may be used one day by an 'undelete' program
+ */
+static void set_inode_dtime (struct inode * inode,
+			     struct ext2_group_desc * gdp)
+{
+	unsigned long inode_block;
+	struct buffer_head * bh;
+	struct ext2_inode * raw_inode;
+
+	inode_block = gdp->bg_inode_table + (((inode->i_ino - 1) %
+			EXT2_INODES_PER_GROUP(inode->i_sb)) /
+			EXT2_INODES_PER_BLOCK(inode->i_sb));
+	bh = bread (inode->i_sb->s_dev, inode_block, inode->i_sb->s_blocksize);
+	if (!bh)
+		ext2_panic (inode->i_sb, "set_inode_dtime",
+			    "Cannot load inode table block - "
+			    "inode=%lu, inode_block=%lu",
+			    inode->i_ino, inode_block);
+	raw_inode = ((struct ext2_inode *) bh->b_data) +
+			(((inode->i_ino - 1) %
+			EXT2_INODES_PER_GROUP(inode->i_sb)) %
+			EXT2_INODES_PER_BLOCK(inode->i_sb));
+	raw_inode->i_links_count = 0;
+	raw_inode->i_dtime = CURRENT_TIME;
+	mark_buffer_dirty(bh, 1);
+	if (IS_SYNC(inode)) {
+		ll_rw_block (WRITE, 1, &bh);
+		wait_on_buffer (bh);
+	}
+	brelse (bh);
+}
+
+void ext2_free_inode (struct inode * inode)
+{
+	struct super_block * sb;
+	struct buffer_head * bh;
+	struct buffer_head * bh2;
+	unsigned long block_group;
+	unsigned long bit;
+	int bitmap_nr;
+	struct ext2_group_desc * gdp;
+	struct ext2_super_block * es;
+
+	if (!inode)
+		return;
+	if (!inode->i_dev) {
+		printk ("ext2_free_inode: inode has no device\n");
+		return;
+	}
+	if (inode->i_count > 1) {
+		printk ("ext2_free_inode: inode has count=%d\n",
+			inode->i_count);
+		return;
+	}
+	if (inode->i_nlink) {
+		printk ("ext2_free_inode: inode has nlink=%d\n",
+			inode->i_nlink);
+		return;
+	}
+	if (!inode->i_sb) {
+		printk("ext2_free_inode: inode on nonexistent device\n");
+		return;
+	}
+
+	ext2_debug ("freeing inode %lu\n", inode->i_ino);
+
+	sb = inode->i_sb;
+	lock_super (sb);
+	if (inode->i_ino < EXT2_FIRST_INO ||
+	    inode->i_ino > sb->u.ext2_sb.s_es->s_inodes_count) {
+		ext2_error (sb, "free_inode",
+			    "reserved inode or nonexistent inode");
+		unlock_super (sb);
+		return;
+	}
+	es = sb->u.ext2_sb.s_es;
+	block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(sb);
+	bit = (inode->i_ino - 1) % EXT2_INODES_PER_GROUP(sb);
+	bitmap_nr = load_inode_bitmap (sb, block_group);
+	bh = sb->u.ext2_sb.s_inode_bitmap[bitmap_nr];
+	if (!clear_bit (bit, bh->b_data))
+		ext2_warning (sb, "ext2_free_inode",
+			      "bit already cleared for inode %lu", inode->i_ino);
+	else {
+		gdp = get_group_desc (sb, block_group, &bh2);
+		gdp->bg_free_inodes_count++;
+		if (S_ISDIR(inode->i_mode))
+			gdp->bg_used_dirs_count--;
+		mark_buffer_dirty(bh2, 1);
+		es->s_free_inodes_count++;
+		mark_buffer_dirty(sb->u.ext2_sb.s_sbh, 1);
+		set_inode_dtime (inode, gdp);
+	}
+	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;
+	clear_inode (inode);
+	unlock_super (sb);
+}
+
+/*
+ * This function increments the inode version number
+ *
+ * This may be used one day by the NFS server
+ */
+static void inc_inode_version (struct inode * inode,
+			       struct ext2_group_desc *gdp,
+			       int mode)
+{
+	unsigned long inode_block;
+	struct buffer_head * bh;
+	struct ext2_inode * raw_inode;
+
+	inode_block = gdp->bg_inode_table + (((inode->i_ino - 1) %
+			EXT2_INODES_PER_GROUP(inode->i_sb)) /
+			EXT2_INODES_PER_BLOCK(inode->i_sb));
+	bh = bread (inode->i_sb->s_dev, inode_block, inode->i_sb->s_blocksize);
+	if (!bh) {
+		ext2_error (inode->i_sb, "inc_inode_version",
+			    "Cannot load inode table block - "
+			    "inode=%lu, inode_block=%lu\n",
+			    inode->i_ino, inode_block);
+		inode->u.ext2_i.i_version = 1;
+		return;
+	}
+	raw_inode = ((struct ext2_inode *) bh->b_data) +
+			(((inode->i_ino - 1) %
+			EXT2_INODES_PER_GROUP(inode->i_sb)) %
+			EXT2_INODES_PER_BLOCK(inode->i_sb));
+	raw_inode->i_version++;
+	inode->u.ext2_i.i_version = raw_inode->i_version;
+	mark_buffer_dirty(bh, 1);
+	brelse (bh);
+}
+
+/*
+ * There are two policies for allocating an inode.  If the new inode is
+ * a directory, then a forward search is made for a block group with both
+ * free space and a low directory-to-inode ratio; if that fails, then of
+ * the groups with above-average free space, that group with the fewest
+ * directories already is chosen.
+ *
+ * For other inodes, search forward from the parent directory\'s block
+ * group to find a free inode.
+ */
+struct inode * ext2_new_inode (const struct inode * dir, int mode)
+{
+	struct super_block * sb;
+	struct buffer_head * bh;
+	struct buffer_head * bh2;
+	int i, j, avefreei;
+	struct inode * inode;
+	int bitmap_nr;
+	struct ext2_group_desc * gdp;
+	struct ext2_group_desc * tmp;
+	struct ext2_super_block * es;
+
+	if (!dir || !(inode = get_empty_inode ()))
+		return NULL;
+	sb = dir->i_sb;
+	inode->i_sb = sb;
+	inode->i_flags = sb->s_flags;
+	lock_super (sb);
+	es = sb->u.ext2_sb.s_es;
+repeat:
+	gdp = NULL; i=0;
+	
+	if (S_ISDIR(mode)) {
+		avefreei = es->s_free_inodes_count /
+			sb->u.ext2_sb.s_groups_count;
+/* I am not yet convinced that this next bit is necessary.
+		i = dir->u.ext2_i.i_block_group;
+		for (j = 0; j < sb->u.ext2_sb.s_groups_count; j++) {
+			tmp = get_group_desc (sb, i, &bh2);
+			if ((tmp->bg_used_dirs_count << 8) < 
+			    tmp->bg_free_inodes_count) {
+				gdp = tmp;
+				break;
+			}
+			else
+			i = ++i % sb->u.ext2_sb.s_groups_count;
+		}
+*/
+		if (!gdp) {
+			for (j = 0; j < sb->u.ext2_sb.s_groups_count; j++) {
+				tmp = get_group_desc (sb, j, &bh2);
+				if (tmp->bg_free_inodes_count &&
+					tmp->bg_free_inodes_count >= avefreei) {
+					if (!gdp || 
+					    (tmp->bg_free_blocks_count >
+					     gdp->bg_free_blocks_count)) {
+						i = j;
+						gdp = tmp;
+					}
+				}
+			}
+		}
+	}
+	else 
+	{
+		/*
+		 * Try to place the inode in its parent directory
+		 */
+		i = dir->u.ext2_i.i_block_group;
+		tmp = get_group_desc (sb, i, &bh2);
+		if (tmp->bg_free_inodes_count)
+			gdp = tmp;
+		else
+		{
+			/*
+			 * Use a quadratic hash to find a group with a
+			 * free inode
+			 */
+			for (j = 1; j < sb->u.ext2_sb.s_groups_count; j <<= 1) {
+				i += j;
+				if (i >= sb->u.ext2_sb.s_groups_count)
+					i -= sb->u.ext2_sb.s_groups_count;
+				tmp = get_group_desc (sb, i, &bh2);
+				if (tmp->bg_free_inodes_count) {
+					gdp = tmp;
+					break;
+				}
+			}
+		}
+		if (!gdp) {
+			/*
+			 * That failed: try linear search for a free inode
+			 */
+			i = dir->u.ext2_i.i_block_group + 1;
+			for (j = 2; j < sb->u.ext2_sb.s_groups_count; j++) {
+				if (++i >= sb->u.ext2_sb.s_groups_count)
+					i = 0;
+				tmp = get_group_desc (sb, i, &bh2);
+				if (tmp->bg_free_inodes_count) {
+					gdp = tmp;
+					break;
+				}
+			}
+		}
+	}
+
+	if (!gdp) {
+		unlock_super (sb);
+		iput(inode);
+		return NULL;
+	}
+	bitmap_nr = load_inode_bitmap (sb, i);
+	bh = sb->u.ext2_sb.s_inode_bitmap[bitmap_nr];
+	if ((j = find_first_zero_bit ((unsigned long *) bh->b_data,
+				      EXT2_INODES_PER_GROUP(sb))) <
+	    EXT2_INODES_PER_GROUP(sb)) {
+		if (set_bit (j, bh->b_data)) {
+			ext2_warning (sb, "ext2_new_inode",
+				      "bit already set for inode %d", j);
+			goto repeat;
+		}
+		mark_buffer_dirty(bh, 1);
+		if (sb->s_flags & MS_SYNCHRONOUS) {
+			ll_rw_block (WRITE, 1, &bh);
+			wait_on_buffer (bh);
+		}
+	} else {
+		if (gdp->bg_free_inodes_count != 0) {
+			ext2_error (sb, "ext2_new_inode",
+				    "Free inodes count corrupted in group %d",
+				    i);
+			unlock_super (sb);
+			iput (inode);
+			return NULL;
+		}
+		goto repeat;
+	}
+	j += i * EXT2_INODES_PER_GROUP(sb) + 1;
+	if (j < EXT2_FIRST_INO || j > es->s_inodes_count) {
+		ext2_error (sb, "ext2_new_inode",
+			    "reserved inode or inode > inodes count - "
+			    "block_group = %d,inode=%d", i, j);
+		unlock_super (sb);
+		iput (inode);
+		return NULL;
+	}
+	gdp->bg_free_inodes_count--;
+	if (S_ISDIR(mode))
+		gdp->bg_used_dirs_count++;
+	mark_buffer_dirty(bh2, 1);
+	es->s_free_inodes_count--;
+	mark_buffer_dirty(sb->u.ext2_sb.s_sbh, 1);
+	sb->s_dirt = 1;
+	inode->i_mode = mode;
+	inode->i_sb = sb;
+	inode->i_count = 1;
+	inode->i_nlink = 1;
+	inode->i_dev = sb->s_dev;
+	inode->i_uid = current->fsuid;
+	if (test_opt (sb, GRPID))
+		inode->i_gid = dir->i_gid;
+	else if (dir->i_mode & S_ISGID) {
+		inode->i_gid = dir->i_gid;
+		if (S_ISDIR(mode))
+			mode |= S_ISGID;
+	} else
+		inode->i_gid = current->fsgid;
+	inode->i_dirt = 1;
+	inode->i_ino = j;
+	inode->i_blksize = sb->s_blocksize;
+	inode->i_blocks = 0;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+	inode->u.ext2_i.i_flags = dir->u.ext2_i.i_flags;
+	if (S_ISLNK(mode))
+		inode->u.ext2_i.i_flags &= ~(EXT2_IMMUTABLE_FL | EXT2_APPEND_FL);
+	inode->u.ext2_i.i_faddr = 0;
+	inode->u.ext2_i.i_frag_no = 0;
+	inode->u.ext2_i.i_frag_size = 0;
+	inode->u.ext2_i.i_file_acl = 0;
+	inode->u.ext2_i.i_dir_acl = 0;
+	inode->u.ext2_i.i_dtime = 0;
+	inode->u.ext2_i.i_block_group = i;
+	inode->i_op = NULL;
+	if (inode->u.ext2_i.i_flags & EXT2_SYNC_FL)
+		inode->i_flags |= MS_SYNCHRONOUS;
+	insert_inode_hash(inode);
+	inc_inode_version (inode, gdp, mode);
+
+	ext2_debug ("allocating inode %lu\n", inode->i_ino);
+
+	unlock_super (sb);
+	return inode;
+}
+
+unsigned long ext2_count_free_inodes (struct super_block * sb)
+{
+#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 (sb);
+	es = sb->u.ext2_sb.s_es;
+	desc_count = 0;
+	bitmap_count = 0;
+	gdp = NULL;
+	for (i = 0; i < sb->u.ext2_sb.s_groups_count; i++) {
+		gdp = get_group_desc (sb, i, NULL);
+		desc_count += gdp->bg_free_inodes_count;
+		bitmap_nr = load_inode_bitmap (sb, i);
+		x = ext2_count_free (sb->u.ext2_sb.s_inode_bitmap[bitmap_nr],
+				     EXT2_INODES_PER_GROUP(sb) / 8);
+		printk ("group %d: stored = %d, counted = %lu\n",
+			i, gdp->bg_free_inodes_count, x);
+		bitmap_count += x;
+	}
+	printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",
+		es->s_free_inodes_count, desc_count, bitmap_count);
+	unlock_super (sb);
+	return desc_count;
+#else
+	return sb->u.ext2_sb.s_es->s_free_inodes_count;
+#endif
+}
+
+void ext2_check_inodes_bitmap (struct super_block * sb)
+{
+	struct ext2_super_block * es;
+	unsigned long desc_count, bitmap_count, x;
+	int bitmap_nr;
+	struct ext2_group_desc * gdp;
+	int i;
+
+	lock_super (sb);
+	es = sb->u.ext2_sb.s_es;
+	desc_count = 0;
+	bitmap_count = 0;
+	gdp = NULL;
+	for (i = 0; i < sb->u.ext2_sb.s_groups_count; i++) {
+		gdp = get_group_desc (sb, i, NULL);
+		desc_count += gdp->bg_free_inodes_count;
+		bitmap_nr = load_inode_bitmap (sb, i);
+		x = ext2_count_free (sb->u.ext2_sb.s_inode_bitmap[bitmap_nr],
+				     EXT2_INODES_PER_GROUP(sb) / 8);
+		if (gdp->bg_free_inodes_count != x)
+			ext2_error (sb, "ext2_check_inodes_bitmap",
+				    "Wrong free inodes count in group %d, "
+				    "stored = %d, counted = %lu", i,
+				    gdp->bg_free_inodes_count, x);
+		bitmap_count += x;
+	}
+	if (es->s_free_inodes_count != bitmap_count)
+		ext2_error (sb, "ext2_check_inodes_bitmap",
+			    "Wrong free inodes count in super block, "
+			    "stored = %lu, counted = %lu",
+			    (unsigned long) es->s_free_inodes_count, bitmap_count);
+	unlock_super (sb);
+}