Initial import

1 files changed, 239 insertions, 0 deletions

diff --git a/fs/sysv/balloc.c b/fs/sysv/balloc.c
new file mode 100644
index 000000000..921c053fc
--- /dev/null
+++ b/fs/sysv/balloc.c
@@ -0,0 +1,239 @@
+/*
+ *  linux/fs/sysv/balloc.c
+ *
+ *  minix/bitmap.c
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext/freelists.c
+ *  Copyright (C) 1992  Remy Card (card@masi.ibp.fr)
+ *
+ *  xenix/alloc.c
+ *  Copyright (C) 1992  Doug Evans
+ *
+ *  coh/alloc.c
+ *  Copyright (C) 1993  Pascal Haible, Bruno Haible
+ *
+ *  sysv/balloc.c
+ *  Copyright (C) 1993  Bruno Haible
+ *
+ *  This file contains code for allocating/freeing blocks.
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/string.h>
+#include "sysv.h"
+
+/* We don't trust the value of
+   sb->sv_sbd2->s_tfree = *sb->sv_free_blocks
+   but we nevertheless keep it up to date. */
+
+static inline sysv_zone_t *get_chunk(struct super_block *sb, struct buffer_head *bh)
+{
+	char *bh_data = bh->b_data;
+
+	if (SYSV_SB(sb)->s_type == FSTYPE_SYSV4)
+		return (sysv_zone_t*)(bh_data+4);
+	else
+		return (sysv_zone_t*)(bh_data+2);
+}
+
+/* NOTE NOTE NOTE: nr is a block number _as_ _stored_ _on_ _disk_ */
+
+void sysv_free_block(struct super_block * sb, sysv_zone_t nr)
+{
+	struct sysv_sb_info * sbi = SYSV_SB(sb);
+	struct buffer_head * bh;
+	sysv_zone_t *blocks = sbi->s_bcache;
+	unsigned count;
+	unsigned block = fs32_to_cpu(sbi, nr);
+
+	/*
+	 * This code does not work at all for AFS (it has a bitmap
+	 * free list).  As AFS is supposed to be read-only no one
+	 * should call this for an AFS filesystem anyway...
+	 */
+	if (sbi->s_type == FSTYPE_AFS)
+		return;
+
+	if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) {
+		printk("sysv_free_block: trying to free block not in datazone\n");
+		return;
+	}
+
+	mutex_lock(&sbi->s_lock);
+	count = fs16_to_cpu(sbi, *sbi->s_bcache_count);
+
+	if (count > sbi->s_flc_size) {
+		printk("sysv_free_block: flc_count > flc_size\n");
+		mutex_unlock(&sbi->s_lock);
+		return;
+	}
+	/* If the free list head in super-block is full, it is copied
+	 * into this block being freed, ditto if it's completely empty
+	 * (applies only on Coherent).
+	 */
+	if (count == sbi->s_flc_size || count == 0) {
+		block += sbi->s_block_base;
+		bh = sb_getblk(sb, block);
+		if (!bh) {
+			printk("sysv_free_block: getblk() failed\n");
+			mutex_unlock(&sbi->s_lock);
+			return;
+		}
+		memset(bh->b_data, 0, sb->s_blocksize);
+		*(__fs16*)bh->b_data = cpu_to_fs16(sbi, count);
+		memcpy(get_chunk(sb,bh), blocks, count * sizeof(sysv_zone_t));
+		mark_buffer_dirty(bh);
+		set_buffer_uptodate(bh);
+		brelse(bh);
+		count = 0;
+	}
+	sbi->s_bcache[count++] = nr;
+
+	*sbi->s_bcache_count = cpu_to_fs16(sbi, count);
+	fs32_add(sbi, sbi->s_free_blocks, 1);
+	dirty_sb(sb);
+	mutex_unlock(&sbi->s_lock);
+}
+
+sysv_zone_t sysv_new_block(struct super_block * sb)
+{
+	struct sysv_sb_info *sbi = SYSV_SB(sb);
+	unsigned int block;
+	sysv_zone_t nr;
+	struct buffer_head * bh;
+	unsigned count;
+
+	mutex_lock(&sbi->s_lock);
+	count = fs16_to_cpu(sbi, *sbi->s_bcache_count);
+
+	if (count == 0) /* Applies only to Coherent FS */
+		goto Enospc;
+	nr = sbi->s_bcache[--count];
+	if (nr == 0)  /* Applies only to Xenix FS, SystemV FS */
+		goto Enospc;
+
+	block = fs32_to_cpu(sbi, nr);
+
+	*sbi->s_bcache_count = cpu_to_fs16(sbi, count);
+
+	if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) {
+		printk("sysv_new_block: new block %d is not in data zone\n",
+			block);
+		goto Enospc;
+	}
+
+	if (count == 0) { /* the last block continues the free list */
+		unsigned count;
+
+		block += sbi->s_block_base;
+		if (!(bh = sb_bread(sb, block))) {
+			printk("sysv_new_block: cannot read free-list block\n");
+			/* retry this same block next time */
+			*sbi->s_bcache_count = cpu_to_fs16(sbi, 1);
+			goto Enospc;
+		}
+		count = fs16_to_cpu(sbi, *(__fs16*)bh->b_data);
+		if (count > sbi->s_flc_size) {
+			printk("sysv_new_block: free-list block with >flc_size entries\n");
+			brelse(bh);
+			goto Enospc;
+		}
+		*sbi->s_bcache_count = cpu_to_fs16(sbi, count);
+		memcpy(sbi->s_bcache, get_chunk(sb, bh),
+				count * sizeof(sysv_zone_t));
+		brelse(bh);
+	}
+	/* Now the free list head in the superblock is valid again. */
+	fs32_add(sbi, sbi->s_free_blocks, -1);
+	dirty_sb(sb);
+	mutex_unlock(&sbi->s_lock);
+	return nr;
+
+Enospc:
+	mutex_unlock(&sbi->s_lock);
+	return 0;
+}
+
+unsigned long sysv_count_free_blocks(struct super_block * sb)
+{
+	struct sysv_sb_info * sbi = SYSV_SB(sb);
+	int sb_count;
+	int count;
+	struct buffer_head * bh = NULL;
+	sysv_zone_t *blocks;
+	unsigned block;
+	int n;
+
+	/*
+	 * This code does not work at all for AFS (it has a bitmap
+	 * free list).  As AFS is supposed to be read-only we just
+	 * lie and say it has no free block at all.
+	 */
+	if (sbi->s_type == FSTYPE_AFS)
+		return 0;
+
+	mutex_lock(&sbi->s_lock);
+	sb_count = fs32_to_cpu(sbi, *sbi->s_free_blocks);
+
+	if (0)
+		goto trust_sb;
+
+	/* this causes a lot of disk traffic ... */
+	count = 0;
+	n = fs16_to_cpu(sbi, *sbi->s_bcache_count);
+	blocks = sbi->s_bcache;
+	while (1) {
+		sysv_zone_t zone;
+		if (n > sbi->s_flc_size)
+			goto E2big;
+		zone = 0;
+		while (n && (zone = blocks[--n]) != 0)
+			count++;
+		if (zone == 0)
+			break;
+
+		block = fs32_to_cpu(sbi, zone);
+		if (bh)
+			brelse(bh);
+
+		if (block < sbi->s_firstdatazone || block >= sbi->s_nzones)
+			goto Einval;
+		block += sbi->s_block_base;
+		bh = sb_bread(sb, block);
+		if (!bh)
+			goto Eio;
+		n = fs16_to_cpu(sbi, *(__fs16*)bh->b_data);
+		blocks = get_chunk(sb, bh);
+	}
+	if (bh)
+		brelse(bh);
+	if (count != sb_count)
+		goto Ecount;
+done:
+	mutex_unlock(&sbi->s_lock);
+	return count;
+
+Einval:
+	printk("sysv_count_free_blocks: new block %d is not in data zone\n",
+		block);
+	goto trust_sb;
+Eio:
+	printk("sysv_count_free_blocks: cannot read free-list block\n");
+	goto trust_sb;
+E2big:
+	printk("sysv_count_free_blocks: >flc_size entries in free-list block\n");
+	if (bh)
+		brelse(bh);
+trust_sb:
+	count = sb_count;
+	goto done;
+Ecount:
+	printk("sysv_count_free_blocks: free block count was %d, "
+		"correcting to %d\n", sb_count, count);
+	if (!(sb->s_flags & MS_RDONLY)) {
+		*sbi->s_free_blocks = cpu_to_fs32(sbi, count);
+		dirty_sb(sb);
+	}
+	goto done;
+}