754661f143
Many struct inode_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
361 lines
8.5 KiB
C
361 lines
8.5 KiB
C
/*
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* fs/bfs/dir.c
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* BFS directory operations.
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* Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
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* Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
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*/
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#include <linux/time.h>
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#include <linux/string.h>
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#include <linux/fs.h>
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#include <linux/smp_lock.h>
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#include <linux/buffer_head.h>
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#include <linux/sched.h>
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#include "bfs.h"
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#undef DEBUG
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#ifdef DEBUG
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#define dprintf(x...) printf(x)
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#else
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#define dprintf(x...)
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#endif
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static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino);
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static struct buffer_head * bfs_find_entry(struct inode * dir,
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const unsigned char * name, int namelen, struct bfs_dirent ** res_dir);
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static int bfs_readdir(struct file * f, void * dirent, filldir_t filldir)
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{
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struct inode * dir = f->f_path.dentry->d_inode;
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struct buffer_head * bh;
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struct bfs_dirent * de;
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unsigned int offset;
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int block;
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lock_kernel();
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if (f->f_pos & (BFS_DIRENT_SIZE-1)) {
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printf("Bad f_pos=%08lx for %s:%08lx\n", (unsigned long)f->f_pos,
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dir->i_sb->s_id, dir->i_ino);
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unlock_kernel();
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return -EBADF;
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}
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while (f->f_pos < dir->i_size) {
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offset = f->f_pos & (BFS_BSIZE-1);
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block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS);
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bh = sb_bread(dir->i_sb, block);
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if (!bh) {
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f->f_pos += BFS_BSIZE - offset;
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continue;
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}
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do {
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de = (struct bfs_dirent *)(bh->b_data + offset);
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if (de->ino) {
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int size = strnlen(de->name, BFS_NAMELEN);
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if (filldir(dirent, de->name, size, f->f_pos, le16_to_cpu(de->ino), DT_UNKNOWN) < 0) {
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brelse(bh);
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unlock_kernel();
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return 0;
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}
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}
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offset += BFS_DIRENT_SIZE;
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f->f_pos += BFS_DIRENT_SIZE;
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} while (offset < BFS_BSIZE && f->f_pos < dir->i_size);
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brelse(bh);
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}
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unlock_kernel();
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return 0;
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}
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const struct file_operations bfs_dir_operations = {
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.read = generic_read_dir,
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.readdir = bfs_readdir,
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.fsync = file_fsync,
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};
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extern void dump_imap(const char *, struct super_block *);
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static int bfs_create(struct inode * dir, struct dentry * dentry, int mode,
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struct nameidata *nd)
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{
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int err;
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struct inode * inode;
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struct super_block * s = dir->i_sb;
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struct bfs_sb_info * info = BFS_SB(s);
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unsigned long ino;
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inode = new_inode(s);
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if (!inode)
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return -ENOSPC;
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lock_kernel();
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ino = find_first_zero_bit(info->si_imap, info->si_lasti);
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if (ino > info->si_lasti) {
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unlock_kernel();
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iput(inode);
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return -ENOSPC;
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}
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set_bit(ino, info->si_imap);
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info->si_freei--;
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inode->i_uid = current->fsuid;
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inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
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inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
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inode->i_blocks = 0;
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inode->i_op = &bfs_file_inops;
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inode->i_fop = &bfs_file_operations;
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inode->i_mapping->a_ops = &bfs_aops;
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inode->i_mode = mode;
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inode->i_ino = ino;
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BFS_I(inode)->i_dsk_ino = ino;
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BFS_I(inode)->i_sblock = 0;
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BFS_I(inode)->i_eblock = 0;
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insert_inode_hash(inode);
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mark_inode_dirty(inode);
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dump_imap("create",s);
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err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, inode->i_ino);
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if (err) {
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inode_dec_link_count(inode);
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iput(inode);
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unlock_kernel();
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return err;
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}
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unlock_kernel();
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d_instantiate(dentry, inode);
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return 0;
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}
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static struct dentry * bfs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
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{
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struct inode * inode = NULL;
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struct buffer_head * bh;
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struct bfs_dirent * de;
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if (dentry->d_name.len > BFS_NAMELEN)
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return ERR_PTR(-ENAMETOOLONG);
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lock_kernel();
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bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
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if (bh) {
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unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
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brelse(bh);
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inode = iget(dir->i_sb, ino);
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if (!inode) {
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unlock_kernel();
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return ERR_PTR(-EACCES);
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}
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}
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unlock_kernel();
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d_add(dentry, inode);
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return NULL;
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}
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static int bfs_link(struct dentry * old, struct inode * dir, struct dentry * new)
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{
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struct inode * inode = old->d_inode;
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int err;
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lock_kernel();
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err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, inode->i_ino);
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if (err) {
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unlock_kernel();
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return err;
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}
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inc_nlink(inode);
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inode->i_ctime = CURRENT_TIME_SEC;
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mark_inode_dirty(inode);
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atomic_inc(&inode->i_count);
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d_instantiate(new, inode);
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unlock_kernel();
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return 0;
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}
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static int bfs_unlink(struct inode * dir, struct dentry * dentry)
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{
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int error = -ENOENT;
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struct inode * inode;
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struct buffer_head * bh;
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struct bfs_dirent * de;
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inode = dentry->d_inode;
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lock_kernel();
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bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
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if (!bh || le16_to_cpu(de->ino) != inode->i_ino)
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goto out_brelse;
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if (!inode->i_nlink) {
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printf("unlinking non-existent file %s:%lu (nlink=%d)\n", inode->i_sb->s_id,
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inode->i_ino, inode->i_nlink);
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inode->i_nlink = 1;
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}
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de->ino = 0;
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mark_buffer_dirty(bh);
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dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
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mark_inode_dirty(dir);
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inode->i_ctime = dir->i_ctime;
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inode_dec_link_count(inode);
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error = 0;
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out_brelse:
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brelse(bh);
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unlock_kernel();
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return error;
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}
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static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry,
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struct inode * new_dir, struct dentry * new_dentry)
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{
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struct inode * old_inode, * new_inode;
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struct buffer_head * old_bh, * new_bh;
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struct bfs_dirent * old_de, * new_de;
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int error = -ENOENT;
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old_bh = new_bh = NULL;
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old_inode = old_dentry->d_inode;
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if (S_ISDIR(old_inode->i_mode))
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return -EINVAL;
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lock_kernel();
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old_bh = bfs_find_entry(old_dir,
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old_dentry->d_name.name,
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old_dentry->d_name.len, &old_de);
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if (!old_bh || le16_to_cpu(old_de->ino) != old_inode->i_ino)
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goto end_rename;
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error = -EPERM;
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new_inode = new_dentry->d_inode;
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new_bh = bfs_find_entry(new_dir,
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new_dentry->d_name.name,
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new_dentry->d_name.len, &new_de);
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if (new_bh && !new_inode) {
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brelse(new_bh);
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new_bh = NULL;
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}
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if (!new_bh) {
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error = bfs_add_entry(new_dir,
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new_dentry->d_name.name,
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new_dentry->d_name.len, old_inode->i_ino);
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if (error)
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goto end_rename;
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}
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old_de->ino = 0;
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old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
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mark_inode_dirty(old_dir);
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if (new_inode) {
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new_inode->i_ctime = CURRENT_TIME_SEC;
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inode_dec_link_count(new_inode);
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}
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mark_buffer_dirty(old_bh);
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error = 0;
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end_rename:
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unlock_kernel();
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brelse(old_bh);
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brelse(new_bh);
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return error;
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}
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const struct inode_operations bfs_dir_inops = {
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.create = bfs_create,
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.lookup = bfs_lookup,
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.link = bfs_link,
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.unlink = bfs_unlink,
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.rename = bfs_rename,
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};
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static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino)
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{
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struct buffer_head * bh;
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struct bfs_dirent * de;
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int block, sblock, eblock, off, eoff;
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int i;
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dprintf("name=%s, namelen=%d\n", name, namelen);
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if (!namelen)
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return -ENOENT;
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if (namelen > BFS_NAMELEN)
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return -ENAMETOOLONG;
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sblock = BFS_I(dir)->i_sblock;
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eblock = BFS_I(dir)->i_eblock;
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eoff = dir->i_size % BFS_BSIZE;
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for (block=sblock; block<=eblock; block++) {
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bh = sb_bread(dir->i_sb, block);
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if(!bh)
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return -ENOSPC;
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for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) {
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de = (struct bfs_dirent *)(bh->b_data + off);
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if (block==eblock && off>=eoff) {
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/* Do not read/interpret the garbage in the end of eblock. */
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de->ino = 0;
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}
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if (!de->ino) {
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if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) {
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dir->i_size += BFS_DIRENT_SIZE;
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dir->i_ctime = CURRENT_TIME_SEC;
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}
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dir->i_mtime = CURRENT_TIME_SEC;
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mark_inode_dirty(dir);
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de->ino = cpu_to_le16((u16)ino);
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for (i=0; i<BFS_NAMELEN; i++)
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de->name[i] = (i < namelen) ? name[i] : 0;
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mark_buffer_dirty(bh);
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brelse(bh);
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return 0;
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}
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}
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brelse(bh);
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}
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return -ENOSPC;
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}
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static inline int bfs_namecmp(int len, const unsigned char * name, const char * buffer)
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{
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if (len < BFS_NAMELEN && buffer[len])
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return 0;
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return !memcmp(name, buffer, len);
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}
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static struct buffer_head * bfs_find_entry(struct inode * dir,
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const unsigned char * name, int namelen, struct bfs_dirent ** res_dir)
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{
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unsigned long block, offset;
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struct buffer_head * bh;
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struct bfs_dirent * de;
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*res_dir = NULL;
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if (namelen > BFS_NAMELEN)
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return NULL;
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bh = NULL;
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block = offset = 0;
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while (block * BFS_BSIZE + offset < dir->i_size) {
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if (!bh) {
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bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
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if (!bh) {
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block++;
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continue;
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}
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}
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de = (struct bfs_dirent *)(bh->b_data + offset);
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offset += BFS_DIRENT_SIZE;
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if (le16_to_cpu(de->ino) && bfs_namecmp(namelen, name, de->name)) {
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*res_dir = de;
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return bh;
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}
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if (offset < bh->b_size)
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continue;
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brelse(bh);
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bh = NULL;
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offset = 0;
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block++;
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}
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brelse(bh);
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return NULL;
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}
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