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-rw-r--r--fs/sysv/balloc.c239
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;
+}
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