--- /dev/null
+/*
+ * linux/fs/sysv/ialloc.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/ialloc.c
+ * Copyright (C) 1993 Bruno Haible
+ *
+ * This file contains code for allocating/freeing inodes.
+ */
+
+#include <linux/kernel.h>
+#include <linux/stddef.h>
+#include <linux/sched.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/buffer_head.h>
+#include <linux/writeback.h>
+#include "sysv.h"
+
+/* We don't trust the value of
+ sb->sv_sbd2->s_tinode = *sb->sv_sb_total_free_inodes
+ but we nevertheless keep it up to date. */
+
+/* An inode on disk is considered free if both i_mode == 0 and i_nlink == 0. */
+
+/* return &sb->sv_sb_fic_inodes[i] = &sbd->s_inode[i]; */
+static inline sysv_ino_t *
+sv_sb_fic_inode(struct super_block * sb, unsigned int i)
+{
+ struct sysv_sb_info *sbi = SYSV_SB(sb);
+
+ if (sbi->s_bh1 == sbi->s_bh2)
+ return &sbi->s_sb_fic_inodes[i];
+ else {
+ /* 512 byte Xenix FS */
+ unsigned int offset = offsetof(struct xenix_super_block, s_inode[i]);
+ if (offset < 512)
+ return (sysv_ino_t*)(sbi->s_sbd1 + offset);
+ else
+ return (sysv_ino_t*)(sbi->s_sbd2 + offset);
+ }
+}
+
+struct sysv_inode *
+sysv_raw_inode(struct super_block *sb, unsigned ino, struct buffer_head **bh)
+{
+ struct sysv_sb_info *sbi = SYSV_SB(sb);
+ struct sysv_inode *res;
+ int block = sbi->s_firstinodezone + sbi->s_block_base;
+
+ block += (ino-1) >> sbi->s_inodes_per_block_bits;
+ *bh = sb_bread(sb, block);
+ if (!*bh)
+ return NULL;
+ res = (struct sysv_inode *)(*bh)->b_data;
+ return res + ((ino-1) & sbi->s_inodes_per_block_1);
+}
+
+static int refill_free_cache(struct super_block *sb)
+{
+ struct sysv_sb_info *sbi = SYSV_SB(sb);
+ struct buffer_head * bh;
+ struct sysv_inode * raw_inode;
+ int i = 0, ino;
+
+ ino = SYSV_ROOT_INO+1;
+ raw_inode = sysv_raw_inode(sb, ino, &bh);
+ if (!raw_inode)
+ goto out;
+ while (ino <= sbi->s_ninodes) {
+ if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0) {
+ *sv_sb_fic_inode(sb,i++) = cpu_to_fs16(SYSV_SB(sb), ino);
+ if (i == sbi->s_fic_size)
+ break;
+ }
+ if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
+ brelse(bh);
+ raw_inode = sysv_raw_inode(sb, ino, &bh);
+ if (!raw_inode)
+ goto out;
+ } else
+ raw_inode++;
+ }
+ brelse(bh);
+out:
+ return i;
+}
+
+void sysv_free_inode(struct inode * inode)
+{
+ struct super_block *sb = inode->i_sb;
+ struct sysv_sb_info *sbi = SYSV_SB(sb);
+ unsigned int ino;
+ struct buffer_head * bh;
+ struct sysv_inode * raw_inode;
+ unsigned count;
+
+ sb = inode->i_sb;
+ ino = inode->i_ino;
+ if (ino <= SYSV_ROOT_INO || ino > sbi->s_ninodes) {
+ printk("sysv_free_inode: inode 0,1,2 or nonexistent inode\n");
+ return;
+ }
+ raw_inode = sysv_raw_inode(sb, ino, &bh);
+ if (!raw_inode) {
+ printk("sysv_free_inode: unable to read inode block on device "
+ "%s\n", inode->i_sb->s_id);
+ return;
+ }
+ mutex_lock(&sbi->s_lock);
+ count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
+ if (count < sbi->s_fic_size) {
+ *sv_sb_fic_inode(sb,count++) = cpu_to_fs16(sbi, ino);
+ *sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
+ }
+ fs16_add(sbi, sbi->s_sb_total_free_inodes, 1);
+ dirty_sb(sb);
+ memset(raw_inode, 0, sizeof(struct sysv_inode));
+ mark_buffer_dirty(bh);
+ mutex_unlock(&sbi->s_lock);
+ brelse(bh);
+}
+
+struct inode * sysv_new_inode(const struct inode * dir, umode_t mode)
+{
+ struct super_block *sb = dir->i_sb;
+ struct sysv_sb_info *sbi = SYSV_SB(sb);
+ struct inode *inode;
+ sysv_ino_t ino;
+ unsigned count;
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_NONE
+ };
+
+ inode = new_inode(sb);
+ if (!inode)
+ return ERR_PTR(-ENOMEM);
+
+ mutex_lock(&sbi->s_lock);
+ count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
+ if (count == 0 || (*sv_sb_fic_inode(sb,count-1) == 0)) {
+ count = refill_free_cache(sb);
+ if (count == 0) {
+ iput(inode);
+ mutex_unlock(&sbi->s_lock);
+ return ERR_PTR(-ENOSPC);
+ }
+ }
+ /* Now count > 0. */
+ ino = *sv_sb_fic_inode(sb,--count);
+ *sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
+ fs16_add(sbi, sbi->s_sb_total_free_inodes, -1);
+ dirty_sb(sb);
+ inode_init_owner(inode, dir, mode);
+ inode->i_ino = fs16_to_cpu(sbi, ino);
+ inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
+ inode->i_blocks = 0;
+ memset(SYSV_I(inode)->i_data, 0, sizeof(SYSV_I(inode)->i_data));
+ SYSV_I(inode)->i_dir_start_lookup = 0;
+ insert_inode_hash(inode);
+ mark_inode_dirty(inode);
+
+ sysv_write_inode(inode, &wbc); /* ensure inode not allocated again */
+ mark_inode_dirty(inode); /* cleared by sysv_write_inode() */
+ /* That's it. */
+ mutex_unlock(&sbi->s_lock);
+ return inode;
+}
+
+unsigned long sysv_count_free_inodes(struct super_block * sb)
+{
+ struct sysv_sb_info *sbi = SYSV_SB(sb);
+ struct buffer_head * bh;
+ struct sysv_inode * raw_inode;
+ int ino, count, sb_count;
+
+ mutex_lock(&sbi->s_lock);
+
+ sb_count = fs16_to_cpu(sbi, *sbi->s_sb_total_free_inodes);
+
+ if (0)
+ goto trust_sb;
+
+ /* this causes a lot of disk traffic ... */
+ count = 0;
+ ino = SYSV_ROOT_INO+1;
+ raw_inode = sysv_raw_inode(sb, ino, &bh);
+ if (!raw_inode)
+ goto Eio;
+ while (ino <= sbi->s_ninodes) {
+ if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
+ count++;
+ if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
+ brelse(bh);
+ raw_inode = sysv_raw_inode(sb, ino, &bh);
+ if (!raw_inode)
+ goto Eio;
+ } else
+ raw_inode++;
+ }
+ brelse(bh);
+ if (count != sb_count)
+ goto Einval;
+out:
+ mutex_unlock(&sbi->s_lock);
+ return count;
+
+Einval:
+ printk("sysv_count_free_inodes: "
+ "free inode count was %d, correcting to %d\n",
+ sb_count, count);
+ if (!(sb->s_flags & MS_RDONLY)) {
+ *sbi->s_sb_total_free_inodes = cpu_to_fs16(SYSV_SB(sb), count);
+ dirty_sb(sb);
+ }
+ goto out;
+
+Eio:
+ printk("sysv_count_free_inodes: unable to read inode table\n");
+trust_sb:
+ count = sb_count;
+ goto out;
+}
Code Review / kvmfornfv.git / blobdiff