102 lines
2.6 KiB
C
102 lines
2.6 KiB
C
/* fs/fat/nfs.c
|
|
*
|
|
* This software is licensed under the terms of the GNU General Public
|
|
* License version 2, as published by the Free Software Foundation, and
|
|
* may be copied, distributed, and modified under those terms.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
*/
|
|
|
|
#include <linux/exportfs.h>
|
|
#include "fat.h"
|
|
|
|
/**
|
|
* Look up a directory inode given its starting cluster.
|
|
*/
|
|
static struct inode *fat_dget(struct super_block *sb, int i_logstart)
|
|
{
|
|
struct msdos_sb_info *sbi = MSDOS_SB(sb);
|
|
struct hlist_head *head;
|
|
struct hlist_node *_p;
|
|
struct msdos_inode_info *i;
|
|
struct inode *inode = NULL;
|
|
|
|
head = sbi->dir_hashtable + fat_dir_hash(i_logstart);
|
|
spin_lock(&sbi->dir_hash_lock);
|
|
hlist_for_each_entry(i, _p, head, i_dir_hash) {
|
|
BUG_ON(i->vfs_inode.i_sb != sb);
|
|
if (i->i_logstart != i_logstart)
|
|
continue;
|
|
inode = igrab(&i->vfs_inode);
|
|
if (inode)
|
|
break;
|
|
}
|
|
spin_unlock(&sbi->dir_hash_lock);
|
|
return inode;
|
|
}
|
|
|
|
static struct inode *fat_nfs_get_inode(struct super_block *sb,
|
|
u64 ino, u32 generation)
|
|
{
|
|
struct inode *inode;
|
|
|
|
if ((ino < MSDOS_ROOT_INO) || (ino == MSDOS_FSINFO_INO))
|
|
return NULL;
|
|
|
|
inode = ilookup(sb, ino);
|
|
if (inode && generation && (inode->i_generation != generation)) {
|
|
iput(inode);
|
|
inode = NULL;
|
|
}
|
|
|
|
return inode;
|
|
}
|
|
|
|
/**
|
|
* Map a NFS file handle to a corresponding dentry.
|
|
* The dentry may or may not be connected to the filesystem root.
|
|
*/
|
|
struct dentry *fat_fh_to_dentry(struct super_block *sb, struct fid *fid,
|
|
int fh_len, int fh_type)
|
|
{
|
|
return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
|
|
fat_nfs_get_inode);
|
|
}
|
|
|
|
/*
|
|
* Find the parent for a file specified by NFS handle.
|
|
* This requires that the handle contain the i_ino of the parent.
|
|
*/
|
|
struct dentry *fat_fh_to_parent(struct super_block *sb, struct fid *fid,
|
|
int fh_len, int fh_type)
|
|
{
|
|
return generic_fh_to_parent(sb, fid, fh_len, fh_type,
|
|
fat_nfs_get_inode);
|
|
}
|
|
|
|
/*
|
|
* Find the parent for a directory that is not currently connected to
|
|
* the filesystem root.
|
|
*
|
|
* On entry, the caller holds child_dir->d_inode->i_mutex.
|
|
*/
|
|
struct dentry *fat_get_parent(struct dentry *child_dir)
|
|
{
|
|
struct super_block *sb = child_dir->d_sb;
|
|
struct buffer_head *bh = NULL;
|
|
struct msdos_dir_entry *de;
|
|
struct inode *parent_inode = NULL;
|
|
|
|
if (!fat_get_dotdot_entry(child_dir->d_inode, &bh, &de)) {
|
|
int parent_logstart = fat_get_start(MSDOS_SB(sb), de);
|
|
parent_inode = fat_dget(sb, parent_logstart);
|
|
}
|
|
brelse(bh);
|
|
|
|
return d_obtain_alias(parent_inode);
|
|
}
|