Contributors: 18
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Namjae Jeon |
861 |
62.21% |
3 |
7.50% |
| Steven J. Magnani |
345 |
24.93% |
2 |
5.00% |
| Linus Torvalds (pre-git) |
53 |
3.83% |
8 |
20.00% |
| OGAWA Hirofumi |
41 |
2.96% |
6 |
15.00% |
| Christoph Hellwig |
19 |
1.37% |
6 |
15.00% |
| David Teigland |
12 |
0.87% |
1 |
2.50% |
| Neil Brown |
11 |
0.79% |
1 |
2.50% |
| Alexey Fisher |
8 |
0.58% |
2 |
5.00% |
| David M. Grimes |
7 |
0.51% |
1 |
2.50% |
| Al Viro |
6 |
0.43% |
1 |
2.50% |
| Amir Goldstein |
5 |
0.36% |
1 |
2.50% |
| Linus Torvalds |
5 |
0.36% |
2 |
5.00% |
| David Howells |
4 |
0.29% |
1 |
2.50% |
| Thomas Gleixner |
2 |
0.14% |
1 |
2.50% |
| Bo Liu |
2 |
0.14% |
1 |
2.50% |
| Chris Mason |
1 |
0.07% |
1 |
2.50% |
| Art Haas |
1 |
0.07% |
1 |
2.50% |
| Dave Hansen |
1 |
0.07% |
1 |
2.50% |
| Total |
1384 |
|
40 |
|
// SPDX-License-Identifier: GPL-2.0-only
/* fs/fat/nfs.c
*/
#include <linux/exportfs.h>
#include "fat.h"
struct fat_fid {
u32 i_gen;
u32 i_pos_low;
u16 i_pos_hi;
u16 parent_i_pos_hi;
u32 parent_i_pos_low;
u32 parent_i_gen;
};
#define FAT_FID_SIZE_WITHOUT_PARENT 3
#define FAT_FID_SIZE_WITH_PARENT (sizeof(struct fat_fid)/sizeof(u32))
/*
* 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 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, 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_ilookup(struct super_block *sb, u64 ino, loff_t i_pos)
{
if (MSDOS_SB(sb)->options.nfs == FAT_NFS_NOSTALE_RO)
return fat_iget(sb, i_pos);
else {
if ((ino < MSDOS_ROOT_INO) || (ino == MSDOS_FSINFO_INO))
return NULL;
return ilookup(sb, ino);
}
}
static struct inode *__fat_nfs_get_inode(struct super_block *sb,
u64 ino, u32 generation, loff_t i_pos)
{
struct inode *inode = fat_ilookup(sb, ino, i_pos);
if (inode && generation && (inode->i_generation != generation)) {
iput(inode);
inode = NULL;
}
if (inode == NULL && MSDOS_SB(sb)->options.nfs == FAT_NFS_NOSTALE_RO) {
struct buffer_head *bh = NULL;
struct msdos_dir_entry *de ;
sector_t blocknr;
int offset;
fat_get_blknr_offset(MSDOS_SB(sb), i_pos, &blocknr, &offset);
bh = sb_bread(sb, blocknr);
if (!bh) {
fat_msg(sb, KERN_ERR,
"unable to read block(%llu) for building NFS inode",
(llu)blocknr);
return inode;
}
de = (struct msdos_dir_entry *)bh->b_data;
/* If a file is deleted on server and client is not updated
* yet, we must not build the inode upon a lookup call.
*/
if (IS_FREE(de[offset].name))
inode = NULL;
else
inode = fat_build_inode(sb, &de[offset], i_pos);
brelse(bh);
}
return inode;
}
static struct inode *fat_nfs_get_inode(struct super_block *sb,
u64 ino, u32 generation)
{
return __fat_nfs_get_inode(sb, ino, generation, 0);
}
static int
fat_encode_fh_nostale(struct inode *inode, __u32 *fh, int *lenp,
struct inode *parent)
{
int len = *lenp;
struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
struct fat_fid *fid = (struct fat_fid *) fh;
loff_t i_pos;
int type = FILEID_FAT_WITHOUT_PARENT;
if (parent) {
if (len < FAT_FID_SIZE_WITH_PARENT) {
*lenp = FAT_FID_SIZE_WITH_PARENT;
return FILEID_INVALID;
}
} else {
if (len < FAT_FID_SIZE_WITHOUT_PARENT) {
*lenp = FAT_FID_SIZE_WITHOUT_PARENT;
return FILEID_INVALID;
}
}
i_pos = fat_i_pos_read(sbi, inode);
*lenp = FAT_FID_SIZE_WITHOUT_PARENT;
fid->i_gen = inode->i_generation;
fid->i_pos_low = i_pos & 0xFFFFFFFF;
fid->i_pos_hi = (i_pos >> 32) & 0xFFFF;
if (parent) {
i_pos = fat_i_pos_read(sbi, parent);
fid->parent_i_pos_hi = (i_pos >> 32) & 0xFFFF;
fid->parent_i_pos_low = i_pos & 0xFFFFFFFF;
fid->parent_i_gen = parent->i_generation;
type = FILEID_FAT_WITH_PARENT;
*lenp = FAT_FID_SIZE_WITH_PARENT;
}
return type;
}
/*
* Map a NFS file handle to a corresponding dentry.
* The dentry may or may not be connected to the filesystem root.
*/
static 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);
}
static struct dentry *fat_fh_to_dentry_nostale(struct super_block *sb,
struct fid *fh, int fh_len,
int fh_type)
{
struct inode *inode = NULL;
struct fat_fid *fid = (struct fat_fid *)fh;
loff_t i_pos;
switch (fh_type) {
case FILEID_FAT_WITHOUT_PARENT:
if (fh_len < FAT_FID_SIZE_WITHOUT_PARENT)
return NULL;
break;
case FILEID_FAT_WITH_PARENT:
if (fh_len < FAT_FID_SIZE_WITH_PARENT)
return NULL;
break;
default:
return NULL;
}
i_pos = fid->i_pos_hi;
i_pos = (i_pos << 32) | (fid->i_pos_low);
inode = __fat_nfs_get_inode(sb, 0, fid->i_gen, i_pos);
return d_obtain_alias(inode);
}
/*
* Find the parent for a file specified by NFS handle.
* This requires that the handle contain the i_ino of the parent.
*/
static 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);
}
static struct dentry *fat_fh_to_parent_nostale(struct super_block *sb,
struct fid *fh, int fh_len,
int fh_type)
{
struct inode *inode = NULL;
struct fat_fid *fid = (struct fat_fid *)fh;
loff_t i_pos;
if (fh_len < FAT_FID_SIZE_WITH_PARENT)
return NULL;
switch (fh_type) {
case FILEID_FAT_WITH_PARENT:
i_pos = fid->parent_i_pos_hi;
i_pos = (i_pos << 32) | (fid->parent_i_pos_low);
inode = __fat_nfs_get_inode(sb, 0, fid->parent_i_gen, i_pos);
break;
}
return d_obtain_alias(inode);
}
/*
* Rebuild the parent for a directory that is not connected
* to the filesystem root
*/
static
struct inode *fat_rebuild_parent(struct super_block *sb, int parent_logstart)
{
int search_clus, clus_to_match;
struct msdos_dir_entry *de;
struct inode *parent = NULL;
struct inode *dummy_grand_parent = NULL;
struct fat_slot_info sinfo;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
sector_t blknr = fat_clus_to_blknr(sbi, parent_logstart);
struct buffer_head *parent_bh = sb_bread(sb, blknr);
if (!parent_bh) {
fat_msg(sb, KERN_ERR,
"unable to read cluster of parent directory");
return NULL;
}
de = (struct msdos_dir_entry *) parent_bh->b_data;
clus_to_match = fat_get_start(sbi, &de[0]);
search_clus = fat_get_start(sbi, &de[1]);
dummy_grand_parent = fat_dget(sb, search_clus);
if (!dummy_grand_parent) {
dummy_grand_parent = new_inode(sb);
if (!dummy_grand_parent) {
brelse(parent_bh);
return parent;
}
dummy_grand_parent->i_ino = iunique(sb, MSDOS_ROOT_INO);
fat_fill_inode(dummy_grand_parent, &de[1]);
MSDOS_I(dummy_grand_parent)->i_pos = -1;
}
if (!fat_scan_logstart(dummy_grand_parent, clus_to_match, &sinfo))
parent = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
brelse(parent_bh);
iput(dummy_grand_parent);
return parent;
}
/*
* Find the parent for a directory that is not currently connected to
* the filesystem root.
*
* On entry, the caller holds d_inode(child_dir)->i_mutex.
*/
static 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;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
if (!fat_get_dotdot_entry(d_inode(child_dir), &bh, &de)) {
int parent_logstart = fat_get_start(sbi, de);
parent_inode = fat_dget(sb, parent_logstart);
if (!parent_inode && sbi->options.nfs == FAT_NFS_NOSTALE_RO)
parent_inode = fat_rebuild_parent(sb, parent_logstart);
}
brelse(bh);
return d_obtain_alias(parent_inode);
}
const struct export_operations fat_export_ops = {
.encode_fh = generic_encode_ino32_fh,
.fh_to_dentry = fat_fh_to_dentry,
.fh_to_parent = fat_fh_to_parent,
.get_parent = fat_get_parent,
};
const struct export_operations fat_export_ops_nostale = {
.encode_fh = fat_encode_fh_nostale,
.fh_to_dentry = fat_fh_to_dentry_nostale,
.fh_to_parent = fat_fh_to_parent_nostale,
.get_parent = fat_get_parent,
};