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namei: saner calling conventions for filename_parentat()

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a) make it reject ERR_PTR() for name
b) make it putname(name) on all other failure exits
c) make it return name on success

again, simplifies the callers

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2015-05-12 17:32:54 -04:00
parent 181c37b6e4
commit 5c31b6cedb
1 changed files with 22 additions and 38 deletions
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60
fs/namei.c
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@ -2166,13 +2166,16 @@ static int path_parentat(int dfd, const struct filename *name,
return err; return err;
} }
static int filename_parentat(int dfd, struct filename *name, static struct filename *filename_parentat(int dfd, struct filename *name,
unsigned int flags, struct path *parent, unsigned int flags, struct path *parent,
struct qstr *last, int *type) struct qstr *last, int *type)
{ {
int retval; int retval;
struct nameidata nd, *saved_nd = set_nameidata(&nd); struct nameidata nd, *saved_nd;
if (IS_ERR(name))
return name;
saved_nd = set_nameidata(&nd);
retval = path_parentat(dfd, name, flags | LOOKUP_RCU, &nd, parent); retval = path_parentat(dfd, name, flags | LOOKUP_RCU, &nd, parent);
if (unlikely(retval == -ECHILD)) if (unlikely(retval == -ECHILD))
retval = path_parentat(dfd, name, flags, &nd, parent); retval = path_parentat(dfd, name, flags, &nd, parent);
@ -2183,32 +2186,30 @@ static int filename_parentat(int dfd, struct filename *name,
*last = nd.last; *last = nd.last;
*type = nd.last_type; *type = nd.last_type;
audit_inode(name, parent->dentry, LOOKUP_PARENT); audit_inode(name, parent->dentry, LOOKUP_PARENT);
} else {
putname(name);
name = ERR_PTR(retval);
} }
restore_nameidata(saved_nd); restore_nameidata(saved_nd);
return retval; return name;
} }
/* does lookup, returns the object with parent locked */ /* does lookup, returns the object with parent locked */
struct dentry *kern_path_locked(const char *name, struct path *path) struct dentry *kern_path_locked(const char *name, struct path *path)
{ {
struct filename *filename = getname_kernel(name); struct filename *filename;
struct dentry *d;
struct qstr last; struct qstr last;
int type; int type;
struct dentry *d;
int err;
filename = filename_parentat(AT_FDCWD, getname_kernel(name), 0, path,
&last, &type);
if (IS_ERR(filename)) if (IS_ERR(filename))
return ERR_CAST(filename); return ERR_CAST(filename);
if (unlikely(type != LAST_NORM)) {
err = filename_parentat(AT_FDCWD, filename, 0, path, &last, &type);
if (err) {
d = ERR_PTR(err);
goto out;
}
if (type != LAST_NORM) {
path_put(path); path_put(path);
d = ERR_PTR(-EINVAL); putname(filename);
goto out; return ERR_PTR(-EINVAL);
} }
mutex_lock_nested(&path->dentry->d_inode->i_mutex, I_MUTEX_PARENT); mutex_lock_nested(&path->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
d = __lookup_hash(&last, path->dentry, 0); d = __lookup_hash(&last, path->dentry, 0);
@ -2216,7 +2217,6 @@ struct dentry *kern_path_locked(const char *name, struct path *path)
mutex_unlock(&path->dentry->d_inode->i_mutex); mutex_unlock(&path->dentry->d_inode->i_mutex);
path_put(path); path_put(path);
} }
out:
putname(filename); putname(filename);
return d; return d;
} }
@ -2325,21 +2325,9 @@ user_path_parent(int dfd, const char __user *path,
int *type, int *type,
unsigned int flags) unsigned int flags)
{ {
struct filename *s = getname(path);
int error;
/* only LOOKUP_REVAL is allowed in extra flags */ /* only LOOKUP_REVAL is allowed in extra flags */
flags &= LOOKUP_REVAL; return filename_parentat(dfd, getname(path), flags & LOOKUP_REVAL,
parent, last, type);
if (IS_ERR(s))
return s;
error = filename_parentat(dfd, s, flags, parent, last, type);
if (error) {
putname(s);
s = ERR_PTR(error);
}
return s;
} }
/** /**
@ -3403,25 +3391,21 @@ static struct dentry *filename_create(int dfd, struct filename *name,
int error; int error;
bool is_dir = (lookup_flags & LOOKUP_DIRECTORY); bool is_dir = (lookup_flags & LOOKUP_DIRECTORY);
if (IS_ERR(name))
return ERR_CAST(name);
/* /*
* Note that only LOOKUP_REVAL and LOOKUP_DIRECTORY matter here. Any * Note that only LOOKUP_REVAL and LOOKUP_DIRECTORY matter here. Any
* other flags passed in are ignored! * other flags passed in are ignored!
*/ */
lookup_flags &= LOOKUP_REVAL; lookup_flags &= LOOKUP_REVAL;
error = filename_parentat(dfd, name, lookup_flags, path, &last, &type); name = filename_parentat(dfd, name, lookup_flags, path, &last, &type);
if (error) { if (IS_ERR(name))
putname(name); return ERR_CAST(name);
return ERR_PTR(error);
}
/* /*
* Yucky last component or no last component at all? * Yucky last component or no last component at all?
* (foo/., foo/.., /////) * (foo/., foo/.., /////)
*/ */
if (type != LAST_NORM) if (unlikely(type != LAST_NORM))
goto out; goto out;
/* don't fail immediately if it's r/o, at least try to report other errors */ /* don't fail immediately if it's r/o, at least try to report other errors */