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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@parcelfarce.linux.theplanet.co.uk
*
* 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/pagemap.h>
#include <linux/quotaops.h>
#include "ext2.h"
#include "xattr.h"
#include "acl.h"
#include "xip.h"
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);
unlock_new_inode(inode);
return 0;
}
inode_dec_link_count(inode);
unlock_new_inode(inode);
iput(inode);
return err;
}
/*
* Methods themselves.
*/
static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
{
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->d_name);
inode = NULL;
if (ino) {
inode = ext2_iget(dir->i_sb, ino);
if (unlikely(IS_ERR(inode))) {
if (PTR_ERR(inode) == -ESTALE) {
ext2_error(dir->i_sb, __func__,
"deleted inode referenced: %lu",
(unsigned long) ino);
return ERR_PTR(-EIO);
} else {
return ERR_CAST(inode);
}
}
}
return d_splice_alias(inode, dentry);
}
struct dentry *ext2_get_parent(struct dentry *child)
{
struct qstr dotdot = {.name = "..", .len = 2};
unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot);
if (!ino)
return ERR_PTR(-ENOENT);
return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino));
}
/*
* 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 nameidata *nd)
{
struct inode *inode;
dquot_initialize(dir);
inode = ext2_new_inode(dir, mode);
if (IS_ERR(inode))
return PTR_ERR(inode);
inode->i_op = &ext2_file_inode_operations;
if (ext2_use_xip(inode->i_sb)) {
inode->i_mapping->a_ops = &ext2_aops_xip;
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
inode->i_fop = &ext2_file_operations;
} else {
inode->i_mapping->a_ops = &ext2_aops;
inode->i_fop = &ext2_file_operations;
}
mark_inode_dirty(inode);
return ext2_add_nondir(dentry, inode);
}
static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
{
struct inode * inode;
int err;
if (!new_valid_dev(rdev))
return -EINVAL;
dquot_initialize(dir);
inode = ext2_new_inode (dir, mode);
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
init_special_inode(inode, inode->i_mode, rdev);
#ifdef CONFIG_EXT2_FS_XATTR
inode->i_op = &ext2_special_inode_operations;
#endif
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;
dquot_initialize(dir);
inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out;
if (l > sizeof (EXT2_I(inode)->i_data)) {
/* slow symlink */
inode->i_op = &ext2_symlink_inode_operations;
if (test_opt(inode->i_sb, NOBH))
inode->i_mapping->a_ops = &ext2_nobh_aops;
else
inode->i_mapping->a_ops = &ext2_aops;
err = page_symlink(inode, symname, l);
if (err)
goto out_fail;
} else {
/* fast symlink */
inode->i_op = &ext2_fast_symlink_inode_operations;
memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
inode->i_size = l-1;
}
mark_inode_dirty(inode);
err = ext2_add_nondir(dentry, inode);
out:
return err;
out_fail:
inode_dec_link_count(inode);
unlock_new_inode(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;
int err;
if (inode->i_nlink >= EXT2_LINK_MAX)
return -EMLINK;
dquot_initialize(dir);
inode->i_ctime = CURRENT_TIME_SEC;
inode_inc_link_count(inode);
atomic_inc(&inode->i_count);
err = ext2_add_link(dentry, inode);
if (!err) {
d_instantiate(dentry, inode);
return 0;
}
inode_dec_link_count(inode);
iput(inode);
return err;
}
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;
dquot_initialize(dir);
inode_inc_link_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;
if (test_opt(inode->i_sb, NOBH))
inode->i_mapping->a_ops = &ext2_nobh_aops;
else
inode->i_mapping->a_ops = &ext2_aops;
inode_inc_link_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);
unlock_new_inode(inode);
out:
return err;
out_fail:
inode_dec_link_count(inode);
inode_dec_link_count(inode);
unlock_new_inode(inode);
iput(inode);
out_dir:
inode_dec_link_count
|