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alistair23-linux/fs/bfs/dir.c
Arjan van de Ven 4b6f5d20b0 [PATCH] Make most file operations structs in fs/ const 
This is a conversion to make the various file_operations structs in fs/
const.  Basically a regexp job, with a few manual fixups

The goal is both to increase correctness (harder to accidentally write to
shared datastructures) and reducing the false sharing of cachelines with
things that get dirty in .data (while .rodata is nicely read only and thus
cache clean)

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 09:16:06 -08:00

364 lines
8.6 KiB
C
Raw Blame History

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