Commit 26fe5750 authored by Linus Torvalds's avatar Linus Torvalds

vfs: make it possible to access the dentry hash/len as one 64-bit entry

This allows comparing hash and len in one operation on 64-bit
architectures.  Right now only __d_lookup_rcu() takes advantage of this,
since that is the case we care most about.

The use of anonymous struct/unions hides the alternate 64-bit approach
from most users, the exception being a few cases where we initialize a
'struct qstr' with a static initializer.  This makes the problematic
cases use a new QSTR_INIT() helper function for that (but initializing
just the name pointer with a "{ .name = xyzzy }" initializer remains
valid, as does just copying another qstr structure).
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ee983e89
......@@ -1502,7 +1502,7 @@ struct dentry *d_make_root(struct inode *root_inode)
struct dentry *res = NULL;
if (root_inode) {
static const struct qstr name = { .name = "/", .len = 1 };
static const struct qstr name = QSTR_INIT("/", 1);
res = __d_alloc(root_inode->i_sb, &name);
if (res)
......@@ -1816,10 +1816,9 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent,
const struct qstr *name,
unsigned *seqp, struct inode *inode)
{
unsigned int len = name->len;
unsigned int hash = name->hash;
u64 hashlen = name->hash_len;
const unsigned char *str = name->name;
struct hlist_bl_head *b = d_hash(parent, hash);
struct hlist_bl_head *b = d_hash(parent, hashlen_hash(hashlen));
struct hlist_bl_node *node;
struct dentry *dentry;
......@@ -1846,9 +1845,6 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent,
hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
unsigned seq;
if (dentry->d_name.hash != hash)
continue;
seqretry:
/*
* The dentry sequence count protects us from concurrent
......@@ -1871,6 +1867,8 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent,
*seqp = seq;
if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) {
if (dentry->d_name.hash != hashlen_hash(hashlen))
continue;
switch (slow_dentry_cmp(parent, inode, dentry, seq, name)) {
case D_COMP_OK:
return dentry;
......@@ -1881,9 +1879,9 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent,
}
}
if (dentry->d_name.len != len)
if (dentry->d_name.hash_len != hashlen)
continue;
if (!dentry_cmp(dentry, str, len))
if (!dentry_cmp(dentry, str, hashlen_len(hashlen)))
return dentry;
}
return NULL;
......
......@@ -79,7 +79,7 @@ static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, str
struct dentry *ext2_get_parent(struct dentry *child)
{
struct qstr dotdot = {.name = "..", .len = 2};
struct qstr dotdot = QSTR_INIT("..", 2);
unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot);
if (!ino)
return ERR_PTR(-ENOENT);
......
......@@ -1045,7 +1045,7 @@ static struct dentry *ext3_lookup(struct inode * dir, struct dentry *dentry, str
struct dentry *ext3_get_parent(struct dentry *child)
{
unsigned long ino;
struct qstr dotdot = {.name = "..", .len = 2};
struct qstr dotdot = QSTR_INIT("..", 2);
struct ext3_dir_entry_2 * de;
struct buffer_head *bh;
......
......@@ -1052,10 +1052,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, stru
struct dentry *ext4_get_parent(struct dentry *child)
{
__u32 ino;
static const struct qstr dotdot = {
.name = "..",
.len = 2,
};
static const struct qstr dotdot = QSTR_INIT("..", 2);
struct ext4_dir_entry_2 * de;
struct buffer_head *bh;
......
......@@ -821,7 +821,7 @@ static struct gfs2_leaf *new_leaf(struct inode *inode, struct buffer_head **pbh,
struct buffer_head *bh;
struct gfs2_leaf *leaf;
struct gfs2_dirent *dent;
struct qstr name = { .name = "", .len = 0, .hash = 0 };
struct qstr name = { .name = "" };
error = gfs2_alloc_blocks(ip, &bn, &n, 0, NULL);
if (error)
......
......@@ -68,7 +68,7 @@ struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct na
int dcache_dir_open(struct inode *inode, struct file *file)
{
static struct qstr cursor_name = {.len = 1, .name = "."};
static struct qstr cursor_name = QSTR_INIT(".", 1);
file->private_data = d_alloc(file->f_path.dentry, &cursor_name);
......@@ -225,7 +225,7 @@ struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
struct dentry *dentry;
struct inode *root;
struct qstr d_name = {.name = name, .len = strlen(name)};
struct qstr d_name = QSTR_INIT(name, strlen(name));
if (IS_ERR(s))
return ERR_CAST(s);
......
......@@ -477,10 +477,7 @@ int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry)
static
void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
{
struct qstr filename = {
.len = entry->len,
.name = entry->name,
};
struct qstr filename = QSTR_INIT(entry->name, entry->len);
struct dentry *dentry;
struct dentry *alias;
struct inode *dir = parent->d_inode;
......
......@@ -398,8 +398,7 @@ nfs3_proc_remove(struct inode *dir, struct qstr *name)
{
struct nfs_removeargs arg = {
.fh = NFS_FH(dir),
.name.len = name->len,
.name.name = name->name,
.name = *name,
};
struct nfs_removeres res;
struct rpc_message msg = {
......
......@@ -2782,8 +2782,7 @@ static int _nfs4_proc_remove(struct inode *dir, struct qstr *name)
struct nfs_server *server = NFS_SERVER(dir);
struct nfs_removeargs args = {
.fh = NFS_FH(dir),
.name.len = name->len,
.name.name = name->name,
.name = *name,
.bitmask = server->attr_bitmask,
};
struct nfs_removeres res = {
......
......@@ -335,8 +335,7 @@ nfs_proc_remove(struct inode *dir, struct qstr *name)
{
struct nfs_removeargs arg = {
.fh = NFS_FH(dir),
.name.len = name->len,
.name.name = name->name,
.name = *name,
};
struct rpc_message msg = {
.rpc_proc = &nfs_procedures[NFSPROC_REMOVE],
......
......@@ -441,7 +441,7 @@ static struct dentry *nilfs_get_parent(struct dentry *child)
{
unsigned long ino;
struct inode *inode;
struct qstr dotdot = {.name = "..", .len = 2};
struct qstr dotdot = QSTR_INIT("..", 2);
struct nilfs_root *root;
ino = nilfs_inode_by_name(child->d_inode, &dotdot);
......
......@@ -2361,7 +2361,7 @@ int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
* by passing 'ubifs_tnc_remove_nm()' the same key but
* an unmatchable name.
*/
struct qstr noname = { .len = 0, .name = "" };
struct qstr noname = { .name = "" };
err = dbg_check_tnc(c, 0);
mutex_unlock(&c->tnc_mutex);
......
......@@ -298,7 +298,7 @@ int ubifs_setxattr(struct dentry *dentry, const char *name,
{
struct inode *inode, *host = dentry->d_inode;
struct ubifs_info *c = host->i_sb->s_fs_info;
struct qstr nm = { .name = name, .len = strlen(name) };
struct qstr nm = QSTR_INIT(name, strlen(name));
struct ubifs_dent_node *xent;
union ubifs_key key;
int err, type;
......@@ -361,7 +361,7 @@ ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
{
struct inode *inode, *host = dentry->d_inode;
struct ubifs_info *c = host->i_sb->s_fs_info;
struct qstr nm = { .name = name, .len = strlen(name) };
struct qstr nm = QSTR_INIT(name, strlen(name));
struct ubifs_inode *ui;
struct ubifs_dent_node *xent;
union ubifs_key key;
......@@ -524,7 +524,7 @@ int ubifs_removexattr(struct dentry *dentry, const char *name)
{
struct inode *inode, *host = dentry->d_inode;
struct ubifs_info *c = host->i_sb->s_fs_info;
struct qstr nm = { .name = name, .len = strlen(name) };
struct qstr nm = QSTR_INIT(name, strlen(name));
struct ubifs_dent_node *xent;
union ubifs_key key;
int err;
......
......@@ -1193,7 +1193,7 @@ static struct dentry *udf_get_parent(struct dentry *child)
{
struct kernel_lb_addr tloc;
struct inode *inode = NULL;
struct qstr dotdot = {.name = "..", .len = 2};
struct qstr dotdot = QSTR_INIT("..", 2);
struct fileIdentDesc cfi;
struct udf_fileident_bh fibh;
......
......@@ -146,10 +146,7 @@ static struct dentry *ufs_fh_to_parent(struct super_block *sb, struct fid *fid,
static struct dentry *ufs_get_parent(struct dentry *child)
{
struct qstr dot_dot = {
.name = "..",
.len = 2,
};
struct qstr dot_dot = QSTR_INIT("..", 2);
ino_t ino;
ino = ufs_inode_by_name(child->d_inode, &dot_dot);
......
......@@ -25,6 +25,13 @@ struct vfsmount;
#define IS_ROOT(x) ((x) == (x)->d_parent)
/* The hash is always the low bits of hash_len */
#ifdef __LITTLE_ENDIAN
#define HASH_LEN_DECLARE u32 hash; u32 len;
#else
#define HASH_LEN_DECLARE u32 len; u32 hash;
#endif
/*
* "quick string" -- eases parameter passing, but more importantly
* saves "metadata" about the string (ie length and the hash).
......@@ -33,11 +40,19 @@ struct vfsmount;
* dentry.
*/
struct qstr {
unsigned int hash;
unsigned int len;
union {
struct {
HASH_LEN_DECLARE;
};
u64 hash_len;
};
const unsigned char *name;
};
#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
#define hashlen_hash(hashlen) ((u32) (hashlen))
#define hashlen_len(hashlen) ((u32)((hashlen) >> 32))
struct dentry_stat_t {
int nr_dentry;
int nr_unused;
......
......@@ -127,9 +127,7 @@ static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
{
static uint32_t clntid;
char name[15];
struct qstr q = {
.name = name,
};
struct qstr q = { .name = name };
struct dentry *dir, *dentry;
int error;
......
......@@ -1059,12 +1059,9 @@ static const struct rpc_filelist files[] = {
struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
const unsigned char *dir_name)
{
struct qstr dir = {
.name = dir_name,
.len = strlen(dir_name),
.hash = full_name_hash(dir_name, strlen(dir_name)),
};
struct qstr dir = QSTR_INIT(dir_name, strlen(dir_name));
dir.hash = full_name_hash(dir.name, dir.len);
return d_lookup(sb->s_root, &dir);
}
EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);
......
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