diff options
Diffstat (limited to 'fs/sysv/ialloc.c')
| -rw-r--r-- | fs/sysv/ialloc.c | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/fs/sysv/ialloc.c b/fs/sysv/ialloc.c new file mode 100644 index 0000000..9b585d1 --- /dev/null +++ b/fs/sysv/ialloc.c @@ -0,0 +1,240 @@ +/* + * 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 "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); + clear_inode(inode); + if (!raw_inode) { + printk("sysv_free_inode: unable to read inode block on device " + "%s\n", inode->i_sb->s_id); + return; + } + lock_super(sb); + 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); + unlock_super(sb); + brelse(bh); +} + +struct inode * sysv_new_inode(const struct inode * dir, mode_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; + + inode = new_inode(sb); + if (!inode) + return ERR_PTR(-ENOMEM); + + lock_super(sb); + 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); + unlock_super(sb); + 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); + + 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_uid = current->fsuid; + inode->i_ino = fs16_to_cpu(sbi, ino); + inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC; + inode->i_blocks = inode->i_blksize = 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); + + inode->i_mode = mode; /* for sysv_write_inode() */ + sysv_write_inode(inode, 0); /* ensure inode not allocated again */ + mark_inode_dirty(inode); /* cleared by sysv_write_inode() */ + /* That's it. */ + unlock_super(sb); + 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; + + lock_super(sb); + + 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: + unlock_super(sb); + 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; +} |
