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namei: shift nameidata down into filename_parentat()

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2015-05-09 11:19:16 -04:00
parent abc9f5beb1
commit 391172c46e
1 changed files with 43 additions and 41 deletions
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84
fs/namei.c
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@ -2146,7 +2146,8 @@ static int filename_lookup(int dfd, struct filename *name, unsigned flags,
/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
static int path_parentat(int dfd, const struct filename *name,
unsigned int flags, struct nameidata *nd)
unsigned int flags, struct nameidata *nd,
struct path *parent)
{
const char *s = path_init(dfd, name, flags, nd);
int err;
@ -2155,26 +2156,34 @@ static int path_parentat(int dfd, const struct filename *name,
err = link_path_walk(s, nd);
if (!err)
err = complete_walk(nd);
if (err)
terminate_walk(nd);
if (!err) {
*parent = nd->path;
nd->path.mnt = NULL;
nd->path.dentry = NULL;
}
terminate_walk(nd);
path_cleanup(nd);
return err;
}
static int filename_parentat(int dfd, struct filename *name,
unsigned int flags, struct nameidata *nd)
unsigned int flags, struct path *parent,
struct qstr *last, int *type)
{
int retval;
struct nameidata *saved_nd = set_nameidata(nd);
struct nameidata nd, *saved_nd = set_nameidata(&nd);
retval = path_parentat(dfd, name, flags | LOOKUP_RCU, nd);
retval = path_parentat(dfd, name, flags | LOOKUP_RCU, &nd, parent);
if (unlikely(retval == -ECHILD))
retval = path_parentat(dfd, name, flags, nd);
retval = path_parentat(dfd, name, flags, &nd, parent);
if (unlikely(retval == -ESTALE))
retval = path_parentat(dfd, name, flags | LOOKUP_REVAL, nd);
if (likely(!retval))
audit_inode(name, nd->path.dentry, LOOKUP_PARENT);
retval = path_parentat(dfd, name, flags | LOOKUP_REVAL,
&nd, parent);
if (likely(!retval)) {
*last = nd.last;
*type = nd.last_type;
audit_inode(name, parent->dentry, LOOKUP_PARENT);
}
restore_nameidata(saved_nd);
return retval;
}
@ -2183,31 +2192,30 @@ static int filename_parentat(int dfd, struct filename *name,
struct dentry *kern_path_locked(const char *name, struct path *path)
{
struct filename *filename = getname_kernel(name);
struct nameidata nd;
struct qstr last;
int type;
struct dentry *d;
int err;
if (IS_ERR(filename))
return ERR_CAST(filename);
err = filename_parentat(AT_FDCWD, filename, 0, &nd);
err = filename_parentat(AT_FDCWD, filename, 0, path, &last, &type);
if (err) {
d = ERR_PTR(err);
goto out;
}
if (nd.last_type != LAST_NORM) {
path_put(&nd.path);
if (type != LAST_NORM) {
path_put(path);
d = ERR_PTR(-EINVAL);
goto out;
}
mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
d = __lookup_hash(&nd.last, nd.path.dentry, 0);
mutex_lock_nested(&path->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
d = __lookup_hash(&last, path->dentry, 0);
if (IS_ERR(d)) {
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
goto out;
mutex_unlock(&path->dentry->d_inode->i_mutex);
path_put(path);
}
*path = nd.path;
out:
putname(filename);
return d;
@ -2317,7 +2325,6 @@ user_path_parent(int dfd, const char __user *path,
int *type,
unsigned int flags)
{
struct nameidata nd;
struct filename *s = getname(path);
int error;
@ -2327,15 +2334,11 @@ user_path_parent(int dfd, const char __user *path,
if (IS_ERR(s))
return s;
error = filename_parentat(dfd, s, flags, &nd);
error = filename_parentat(dfd, s, flags, parent, last, type);
if (error) {
putname(s);
return ERR_PTR(error);
s = ERR_PTR(error);
}
*parent = nd.path;
*last = nd.last;
*type = nd.last_type;
return s;
}
@ -3394,7 +3397,8 @@ static struct dentry *filename_create(int dfd, struct filename *name,
struct path *path, unsigned int lookup_flags)
{
struct dentry *dentry = ERR_PTR(-EEXIST);
struct nameidata nd;
struct qstr last;
int type;
int err2;
int error;
bool is_dir = (lookup_flags & LOOKUP_DIRECTORY);
@ -3405,7 +3409,7 @@ static struct dentry *filename_create(int dfd, struct filename *name,
*/
lookup_flags &= LOOKUP_REVAL;
error = filename_parentat(dfd, name, lookup_flags, &nd);
error = filename_parentat(dfd, name, lookup_flags, path, &last, &type);
if (error)
return ERR_PTR(error);
@ -3413,18 +3417,17 @@ static struct dentry *filename_create(int dfd, struct filename *name,
* Yucky last component or no last component at all?
* (foo/., foo/.., /////)
*/
if (nd.last_type != LAST_NORM)
if (type != LAST_NORM)
goto out;
nd.flags &= ~LOOKUP_PARENT;
nd.flags |= LOOKUP_CREATE | LOOKUP_EXCL;
/* don't fail immediately if it's r/o, at least try to report other errors */
err2 = mnt_want_write(nd.path.mnt);
err2 = mnt_want_write(path->mnt);
/*
* Do the final lookup.
*/
mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
dentry = __lookup_hash(&nd.last, nd.path.dentry, nd.flags);
lookup_flags |= LOOKUP_CREATE | LOOKUP_EXCL;
mutex_lock_nested(&path->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
dentry = __lookup_hash(&last, path->dentry, lookup_flags);
if (IS_ERR(dentry))
goto unlock;
@ -3438,7 +3441,7 @@ static struct dentry *filename_create(int dfd, struct filename *name,
* all is fine. Let's be bastards - you had / on the end, you've
* been asking for (non-existent) directory. -ENOENT for you.
*/
if (unlikely(!is_dir && nd.last.name[nd.last.len])) {
if (unlikely(!is_dir && last.name[last.len])) {
error = -ENOENT;
goto fail;
}
@ -3446,17 +3449,16 @@ static struct dentry *filename_create(int dfd, struct filename *name,
error = err2;
goto fail;
}
*path = nd.path;
return dentry;
fail:
dput(dentry);
dentry = ERR_PTR(error);
unlock:
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
mutex_unlock(&path->dentry->d_inode->i_mutex);
if (!err2)
mnt_drop_write(nd.path.mnt);
mnt_drop_write(path->mnt);
out:
path_put(&nd.path);
path_put(path);
return dentry;
}