linux_dsm_epyc7002/fs/affs/namei.c
Linus Torvalds 8387ff2577 vfs: make the string hashes salt the hash
We always mixed in the parent pointer into the dentry name hash, but we
did it late at lookup time.  It turns out that we can simplify that
lookup-time action by salting the hash with the parent pointer early
instead of late.

A few other users of our string hashes also wanted to mix in their own
pointers into the hash, and those are updated to use the same mechanism.

Hash users that don't have any particular initial salt can just use the
NULL pointer as a no-salt.

Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: George Spelvin <linux@sciencehorizons.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-10 20:21:46 -07:00

464 lines
11 KiB
C

/*
* linux/fs/affs/namei.c
*
* (c) 1996 Hans-Joachim Widmaier - Rewritten
*
* (C) 1993 Ray Burr - Modified for Amiga FFS filesystem.
*
* (C) 1991 Linus Torvalds - minix filesystem
*/
#include "affs.h"
typedef int (*toupper_t)(int);
static int affs_toupper(int ch);
static int affs_hash_dentry(const struct dentry *, struct qstr *);
static int affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
unsigned int len, const char *str, const struct qstr *name);
static int affs_intl_toupper(int ch);
static int affs_intl_hash_dentry(const struct dentry *, struct qstr *);
static int affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
unsigned int len, const char *str, const struct qstr *name);
const struct dentry_operations affs_dentry_operations = {
.d_hash = affs_hash_dentry,
.d_compare = affs_compare_dentry,
};
const struct dentry_operations affs_intl_dentry_operations = {
.d_hash = affs_intl_hash_dentry,
.d_compare = affs_intl_compare_dentry,
};
/* Simple toupper() for DOS\1 */
static int
affs_toupper(int ch)
{
return ch >= 'a' && ch <= 'z' ? ch -= ('a' - 'A') : ch;
}
/* International toupper() for DOS\3 ("international") */
static int
affs_intl_toupper(int ch)
{
return (ch >= 'a' && ch <= 'z') || (ch >= 0xE0
&& ch <= 0xFE && ch != 0xF7) ?
ch - ('a' - 'A') : ch;
}
static inline toupper_t
affs_get_toupper(struct super_block *sb)
{
return affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL) ?
affs_intl_toupper : affs_toupper;
}
/*
* Note: the dentry argument is the parent dentry.
*/
static inline int
__affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr, toupper_t toupper, bool notruncate)
{
const u8 *name = qstr->name;
unsigned long hash;
int retval;
u32 len;
retval = affs_check_name(qstr->name, qstr->len, notruncate);
if (retval)
return retval;
hash = init_name_hash(dentry);
len = min(qstr->len, AFFSNAMEMAX);
for (; len > 0; name++, len--)
hash = partial_name_hash(toupper(*name), hash);
qstr->hash = end_name_hash(hash);
return 0;
}
static int
affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
{
return __affs_hash_dentry(dentry, qstr, affs_toupper,
affs_nofilenametruncate(dentry));
}
static int
affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
{
return __affs_hash_dentry(dentry, qstr, affs_intl_toupper,
affs_nofilenametruncate(dentry));
}
static inline int __affs_compare_dentry(unsigned int len,
const char *str, const struct qstr *name, toupper_t toupper,
bool notruncate)
{
const u8 *aname = str;
const u8 *bname = name->name;
/*
* 'str' is the name of an already existing dentry, so the name
* must be valid. 'name' must be validated first.
*/
if (affs_check_name(name->name, name->len, notruncate))
return 1;
/*
* If the names are longer than the allowed 30 chars,
* the excess is ignored, so their length may differ.
*/
if (len >= AFFSNAMEMAX) {
if (name->len < AFFSNAMEMAX)
return 1;
len = AFFSNAMEMAX;
} else if (len != name->len)
return 1;
for (; len > 0; len--)
if (toupper(*aname++) != toupper(*bname++))
return 1;
return 0;
}
static int
affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
unsigned int len, const char *str, const struct qstr *name)
{
return __affs_compare_dentry(len, str, name, affs_toupper,
affs_nofilenametruncate(parent));
}
static int
affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
unsigned int len, const char *str, const struct qstr *name)
{
return __affs_compare_dentry(len, str, name, affs_intl_toupper,
affs_nofilenametruncate(parent));
}
/*
* NOTE! unlike strncmp, affs_match returns 1 for success, 0 for failure.
*/
static inline int
affs_match(struct dentry *dentry, const u8 *name2, toupper_t toupper)
{
const u8 *name = dentry->d_name.name;
int len = dentry->d_name.len;
if (len >= AFFSNAMEMAX) {
if (*name2 < AFFSNAMEMAX)
return 0;
len = AFFSNAMEMAX;
} else if (len != *name2)
return 0;
for (name2++; len > 0; len--)
if (toupper(*name++) != toupper(*name2++))
return 0;
return 1;
}
int
affs_hash_name(struct super_block *sb, const u8 *name, unsigned int len)
{
toupper_t toupper = affs_get_toupper(sb);
u32 hash;
hash = len = min(len, AFFSNAMEMAX);
for (; len > 0; len--)
hash = (hash * 13 + toupper(*name++)) & 0x7ff;
return hash % AFFS_SB(sb)->s_hashsize;
}
static struct buffer_head *
affs_find_entry(struct inode *dir, struct dentry *dentry)
{
struct super_block *sb = dir->i_sb;
struct buffer_head *bh;
toupper_t toupper = affs_get_toupper(sb);
u32 key;
pr_debug("%s(\"%pd\")\n", __func__, dentry);
bh = affs_bread(sb, dir->i_ino);
if (!bh)
return ERR_PTR(-EIO);
key = be32_to_cpu(AFFS_HEAD(bh)->table[affs_hash_name(sb, dentry->d_name.name, dentry->d_name.len)]);
for (;;) {
affs_brelse(bh);
if (key == 0)
return NULL;
bh = affs_bread(sb, key);
if (!bh)
return ERR_PTR(-EIO);
if (affs_match(dentry, AFFS_TAIL(sb, bh)->name, toupper))
return bh;
key = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
}
}
struct dentry *
affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
struct super_block *sb = dir->i_sb;
struct buffer_head *bh;
struct inode *inode = NULL;
pr_debug("%s(\"%pd\")\n", __func__, dentry);
affs_lock_dir(dir);
bh = affs_find_entry(dir, dentry);
affs_unlock_dir(dir);
if (IS_ERR(bh))
return ERR_CAST(bh);
if (bh) {
u32 ino = bh->b_blocknr;
/* store the real header ino in d_fsdata for faster lookups */
dentry->d_fsdata = (void *)(long)ino;
switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
//link to dirs disabled
//case ST_LINKDIR:
case ST_LINKFILE:
ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
}
affs_brelse(bh);
inode = affs_iget(sb, ino);
if (IS_ERR(inode))
return ERR_CAST(inode);
}
d_add(dentry, inode);
return NULL;
}
int
affs_unlink(struct inode *dir, struct dentry *dentry)
{
pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
d_inode(dentry)->i_ino, dentry);
return affs_remove_header(dentry);
}
int
affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
{
struct super_block *sb = dir->i_sb;
struct inode *inode;
int error;
pr_debug("%s(%lu,\"%pd\",0%ho)\n",
__func__, dir->i_ino, dentry, mode);
inode = affs_new_inode(dir);
if (!inode)
return -ENOSPC;
inode->i_mode = mode;
mode_to_prot(inode);
mark_inode_dirty(inode);
inode->i_op = &affs_file_inode_operations;
inode->i_fop = &affs_file_operations;
inode->i_mapping->a_ops = affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS) ?
&affs_aops_ofs : &affs_aops;
error = affs_add_entry(dir, inode, dentry, ST_FILE);
if (error) {
clear_nlink(inode);
iput(inode);
return error;
}
return 0;
}
int
affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
struct inode *inode;
int error;
pr_debug("%s(%lu,\"%pd\",0%ho)\n",
__func__, dir->i_ino, dentry, mode);
inode = affs_new_inode(dir);
if (!inode)
return -ENOSPC;
inode->i_mode = S_IFDIR | mode;
mode_to_prot(inode);
inode->i_op = &affs_dir_inode_operations;
inode->i_fop = &affs_dir_operations;
error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
if (error) {
clear_nlink(inode);
mark_inode_dirty(inode);
iput(inode);
return error;
}
return 0;
}
int
affs_rmdir(struct inode *dir, struct dentry *dentry)
{
pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
d_inode(dentry)->i_ino, dentry);
return affs_remove_header(dentry);
}
int
affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
{
struct super_block *sb = dir->i_sb;
struct buffer_head *bh;
struct inode *inode;
char *p;
int i, maxlen, error;
char c, lc;
pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
__func__, dir->i_ino, dentry, symname);
maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
inode = affs_new_inode(dir);
if (!inode)
return -ENOSPC;
inode->i_op = &affs_symlink_inode_operations;
inode_nohighmem(inode);
inode->i_data.a_ops = &affs_symlink_aops;
inode->i_mode = S_IFLNK | 0777;
mode_to_prot(inode);
error = -EIO;
bh = affs_bread(sb, inode->i_ino);
if (!bh)
goto err;
i = 0;
p = (char *)AFFS_HEAD(bh)->table;
lc = '/';
if (*symname == '/') {
struct affs_sb_info *sbi = AFFS_SB(sb);
while (*symname == '/')
symname++;
spin_lock(&sbi->symlink_lock);
while (sbi->s_volume[i]) /* Cannot overflow */
*p++ = sbi->s_volume[i++];
spin_unlock(&sbi->symlink_lock);
}
while (i < maxlen && (c = *symname++)) {
if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
*p++ = '/';
i++;
symname += 2;
lc = '/';
} else if (c == '.' && lc == '/' && *symname == '/') {
symname++;
lc = '/';
} else {
*p++ = c;
lc = c;
i++;
}
if (lc == '/')
while (*symname == '/')
symname++;
}
*p = 0;
mark_buffer_dirty_inode(bh, inode);
affs_brelse(bh);
mark_inode_dirty(inode);
error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
if (error)
goto err;
return 0;
err:
clear_nlink(inode);
mark_inode_dirty(inode);
iput(inode);
return error;
}
int
affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
{
struct inode *inode = d_inode(old_dentry);
pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
dentry);
return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
}
int
affs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
struct super_block *sb = old_dir->i_sb;
struct buffer_head *bh = NULL;
int retval;
pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
retval = affs_check_name(new_dentry->d_name.name,
new_dentry->d_name.len,
affs_nofilenametruncate(old_dentry));
if (retval)
return retval;
/* Unlink destination if it already exists */
if (d_really_is_positive(new_dentry)) {
retval = affs_remove_header(new_dentry);
if (retval)
return retval;
}
bh = affs_bread(sb, d_inode(old_dentry)->i_ino);
if (!bh)
return -EIO;
/* Remove header from its parent directory. */
affs_lock_dir(old_dir);
retval = affs_remove_hash(old_dir, bh);
affs_unlock_dir(old_dir);
if (retval)
goto done;
/* And insert it into the new directory with the new name. */
affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
affs_fix_checksum(sb, bh);
affs_lock_dir(new_dir);
retval = affs_insert_hash(new_dir, bh);
affs_unlock_dir(new_dir);
/* TODO: move it back to old_dir, if error? */
done:
mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
affs_brelse(bh);
return retval;
}