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/*
* linux/fs/ext2/namei.c
*
* Rewrite to pagecache. Almost all code had been changed, so blame me
* if the things go wrong. Please, send bug reports to viro@math.psu.edu
*
* Stuff here is basically a glue between the VFS and generic UNIXish
* filesystem that keeps everything in pagecache. All knowledge of the
* directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
* and it's easier to debug that way. In principle we might want to
* generalize that a bit and turn it into a library. Or not.
*
* The only non-static object here is ext2_dir_inode_operations.
*
* TODO: get rid of kmap() use, add readahead.
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/namei.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
*/
#include <linux/fs.h>
#include <linux/ext2_fs.h>
#include <linux/pagemap.h>
/*
* Couple of helper functions - make the code slightly cleaner.
*/
static inline void ext2_inc_count(struct inode *inode)
{
inode->i_nlink++;
mark_inode_dirty(inode);
}
static inline void ext2_dec_count(struct inode *inode)
{
inode->i_nlink--;
mark_inode_dirty(inode);
}
static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
{
int err = ext2_add_link(dentry, inode);
if (!err) {
d_instantiate(dentry, inode);
return 0;
}
ext2_dec_count(inode);
iput(inode);
return err;
}
/*
* Methods themselves.
*/
static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry)
{
struct inode * inode;
ino_t ino;
if (dentry->d_name.len > EXT2_NAME_LEN)
return ERR_PTR(-ENAMETOOLONG);
ino = ext2_inode_by_name(dir, dentry);
inode = NULL;
if (ino) {
inode = iget(dir->i_sb, ino);
if (!inode)
return ERR_PTR(-EACCES);
}
d_add(dentry, inode);
return NULL;
}
/*
* By the time this is called, we already have created
* the directory cache entry for the new file, but it
* is so far negative - it has no inode.
*
* If the create succeeds, we fill in the inode information
* with d_instantiate().
*/
static int ext2_create (struct inode * dir, struct dentry * dentry, int mode)
{
struct inode * inode = ext2_new_inode (dir, mode);
int err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
inode->i_op = &ext2_file_inode_operations;
inode->i_fop = &ext2_file_operations;
inode->i_mapping->a_ops = &ext2_aops;
mark_inode_dirty(inode);
err = ext2_add_nondir(dentry, inode);
}
return err;
}
static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, int rdev)
{
struct inode * inode = ext2_new_inode (dir, mode);
int err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
init_special_inode(inode, mode, rdev);
mark_inode_dirty(inode);
err = ext2_add_nondir(dentry, inode);
}
return err;
}
static int ext2_symlink (struct inode * dir, struct dentry * dentry,
const char * symname)
{
struct super_block * sb = dir->i_sb;
int err = -ENAMETOOLONG;
unsigned l = strlen(symname)+1;
struct inode * inode;
if (l > sb->s_blocksize)
goto out;
inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out;
if (l > sizeof (inode->u.ext2_i.i_data)) {
/* slow symlink */
inode->i_op = &page_symlink_inode_operations;
inode->i_mapping->a_ops = &ext2_aops;
err = block_symlink(inode, symname, l);
if (err)
goto out_fail;
} else {
/* fast symlink */
inode->i_op = &ext2_fast_symlink_inode_operations;
memcpy((char*)&inode->u.ext2_i.i_data,symname,l);
inode->i_size = l-1;
}
mark_inode_dirty(inode);
err = ext2_add_nondir(dentry, inode);
out:
return err;
out_fail:
ext2_dec_count(inode);
iput (inode);
goto out;
}
static int ext2_link (struct dentry * old_dentry, struct inode * dir,
struct dentry *dentry)
{
struct inode *inode = old_dentry->d_inode;
if (S_ISDIR(inode->i_mode))
return -EPERM;
if (inode->i_nlink >= EXT2_LINK_MAX)
return -EMLINK;
inode->i_ctime = CURRENT_TIME;
ext2_inc_count(inode);
atomic_inc(&inode->i_count);
return ext2_add_nondir(dentry, inode);
}
static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
{
struct inode * inode;
int err = -EMLINK;
if (dir->i_nlink >= EXT2_LINK_MAX)
goto out;
ext2_inc_count(dir);
inode = ext2_new_inode (dir, S_IFDIR | mode);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_dir;
inode->i_op = &ext2_dir_inode_operations;
inode->i_fop = &ext2_dir_operations;
inode->i_mapping->a_ops = &ext2_aops;
ext2_inc_count(inode);
err = ext2_make_empty(inode, dir);
if (err)
goto out_fail;
err = ext2_add_link(dentry, inode);
if (err)
goto out_fail;
d_instantiate(dentry, inode);
out:
return err;
out_fail:
ext2_dec_count(inode);
ext2_dec_count(inode);
iput(inode);
out_dir:
ext2_dec_count(dir);
goto out;
}
static int ext2_unlink(struct inode * dir, struct dentry *dentry)
{
struct inode * inode = dentry->d_inode;
struct ext2_dir_entry_2 * de;
struct page * page;
int err = -ENOENT;
de = ext2_find_entry (dir, dentry, &page);
if (!de)
goto out;
err = ext2_delete_entry (de, page);
if (err)
goto out;
inode->i_ctime = dir->i_ctime;
ext2_dec_count(inode);
err = 0;
out:
return err;
}
static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
{
struct inode * inode = dentry->d_inode;
int err = -ENOTEMPTY;
if (ext2_empty_dir(inode)) {
err = ext2_unlink(dir, dentry);
if (!err) {
inode->i_size = 0;
ext2_dec_count(inode);
ext2_dec_count(dir);
}
}
return err;
}
static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry )
{
struct inode * old_inode = old_dentry->d_inode;
struct inode * new_inode = new_dentry->d_inode;
struct page * dir_page = NULL;
struct ext2_dir_entry_2 * dir_de = NULL;
struct page * old_page;
struct ext2_dir_entry_2 * old_de;
int err = -ENOENT;
old_de = ext2_find_entry (old_dir, old_dentry, &old_page);
if (!old_de)
goto out;
if (S_ISDIR(old_inode->i_mode)) {
err = -EIO;
dir_de = ext2_dotdot(old_inode, &dir_page);
if (!dir_de)
goto out_old;
}
if (new_inode) {
struct page *new_page;
struct ext2_dir_entry_2 *new_de;
err = -ENOTEMPTY;
if (dir_de && !ext2_empty_dir (new_inode))
goto out_dir;
err = -ENOENT;
new_de = ext2_find_entry (new_dir, new_dentry, &new_page);
if (!new_de)
goto out_dir;
ext2_inc_count(old_inode);
ext2_set_link(new_dir, new_de, new_page, old_inode);
new_inode->i_ctime = CURRENT_TIME;
if (dir_de)
new_inode->i_nlink--;
ext2_dec_count(new_inode);
} else {
if (dir_de) {
err = -EMLINK;
if (new_dir->i_nlink >= EXT2_LINK_MAX)
goto out_dir;
}
ext2_inc_count(old_inode);
err = ext2_add_link(new_dentry, old_inode);
if (err) {
ext2_dec_count(old_inode);
goto out_dir;
}
if (dir_de)
ext2_inc_count(new_dir);
}
ext2_delete_entry (old_de, old_page);
ext2_dec_count(old_inode);
if (dir_de) {
ext2_set_link(old_inode, dir_de, dir_page, new_dir);
ext2_dec_count(old_dir);
}
return 0;
out_dir:
if (dir_de) {
kunmap(dir_page);
page_cache_release(dir_page);
}
out_old:
kunmap(old_page);
page_cache_release(old_page);
out:
return err;
}
struct inode_operations ext2_dir_inode_operations = {
create: ext2_create,
lookup: ext2_lookup,
link: ext2_link,
unlink: ext2_unlink,
symlink: ext2_symlink,
mkdir: ext2_mkdir,
rmdir: ext2_rmdir,
mknod: ext2_mknod,
rename: ext2_rename,
};
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