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Subject[PATCH 08/21] namei: pass the struct path to store the result down into path_lookupat()
Date
From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 72 +++++++++++++++++++++++++++++---------------------------------
1 file changed, 34 insertions(+), 38 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index ffa2e13..937ec33 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2084,8 +2084,8 @@ static inline int lookup_last(struct nameidata *nd)
}

/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
-static int path_lookupat(int dfd, const struct filename *name,
- unsigned int flags, struct nameidata *nd)
+static int path_lookupat(int dfd, const struct filename *name, unsigned flags,
+ struct nameidata *nd, struct path *path)
{
const char *s = path_init(dfd, name, flags, nd);
int err;
@@ -2106,27 +2106,31 @@ static int path_lookupat(int dfd, const struct filename *name,
if (!err && nd->flags & LOOKUP_DIRECTORY)
if (!d_can_lookup(nd->path.dentry))
err = -ENOTDIR;
- if (err)
- terminate_walk(nd);
-
+ if (!err) {
+ *path = nd->path;
+ nd->path.mnt = NULL;
+ nd->path.dentry = NULL;
+ }
+ terminate_walk(nd);
path_cleanup(nd);
return err;
}

-static int filename_lookup(int dfd, struct filename *name,
- unsigned int flags, struct nameidata *nd)
+static int filename_lookup(int dfd, struct filename *name, unsigned flags,
+ struct nameidata *nd, struct path *path)
{
int retval;
struct nameidata *saved_nd = set_nameidata(nd);

- retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd);
+ retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd, path);
if (unlikely(retval == -ECHILD))
- retval = path_lookupat(dfd, name, flags, nd);
+ retval = path_lookupat(dfd, name, flags, nd, path);
if (unlikely(retval == -ESTALE))
- retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL, nd);
+ retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL,
+ nd, path);

if (likely(!retval))
- audit_inode(name, nd->path.dentry, flags & LOOKUP_PARENT);
+ audit_inode(name, path->dentry, flags & LOOKUP_PARENT);
restore_nameidata(saved_nd);
return retval;
}
@@ -2207,10 +2211,8 @@ int kern_path(const char *name, unsigned int flags, struct path *path)
int res = PTR_ERR(filename);

if (!IS_ERR(filename)) {
- res = filename_lookup(AT_FDCWD, filename, flags, &nd);
+ res = filename_lookup(AT_FDCWD, filename, flags, &nd, path);
putname(filename);
- if (!res)
- *path = nd.path;
}
return res;
}
@@ -2239,9 +2241,7 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
nd.root.dentry = dentry;
nd.root.mnt = mnt;
err = filename_lookup(AT_FDCWD, filename,
- flags | LOOKUP_ROOT, &nd);
- if (!err)
- *path = nd.path;
+ flags | LOOKUP_ROOT, &nd, path);
putname(filename);
}
return err;
@@ -2309,10 +2309,8 @@ int user_path_at_empty(int dfd, const char __user *name, unsigned flags,

BUG_ON(flags & LOOKUP_PARENT);

- err = filename_lookup(dfd, tmp, flags, &nd);
+ err = filename_lookup(dfd, tmp, flags, &nd, path);
putname(tmp);
- if (!err)
- *path = nd.path;
}
return err;
}
@@ -3259,44 +3257,42 @@ static int do_tmpfile(int dfd, struct filename *pathname,
struct file *file, int *opened)
{
static const struct qstr name = QSTR_INIT("/", 1);
- struct dentry *dentry, *child;
+ struct dentry *child;
struct inode *dir;
+ struct path path;
int error = path_lookupat(dfd, pathname,
- flags | LOOKUP_DIRECTORY, nd);
+ flags | LOOKUP_DIRECTORY, nd, &path);
if (unlikely(error))
return error;
- error = mnt_want_write(nd->path.mnt);
+ error = mnt_want_write(path.mnt);
if (unlikely(error))
goto out;
+ dir = path.dentry->d_inode;
/* we want directory to be writable */
- error = inode_permission(nd->inode, MAY_WRITE | MAY_EXEC);
+ error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
if (error)
goto out2;
- dentry = nd->path.dentry;
- dir = dentry->d_inode;
if (!dir->i_op->tmpfile) {
error = -EOPNOTSUPP;
goto out2;
}
- child = d_alloc(dentry, &name);
+ child = d_alloc(path.dentry, &name);
if (unlikely(!child)) {
error = -ENOMEM;
goto out2;
}
- nd->flags &= ~LOOKUP_DIRECTORY;
- nd->flags |= op->intent;
- dput(nd->path.dentry);
- nd->path.dentry = child;
- error = dir->i_op->tmpfile(dir, nd->path.dentry, op->mode);
+ dput(path.dentry);
+ path.dentry = child;
+ error = dir->i_op->tmpfile(dir, child, op->mode);
if (error)
goto out2;
- audit_inode(pathname, nd->path.dentry, 0);
+ audit_inode(pathname, child, 0);
/* Don't check for other permissions, the inode was just created */
- error = may_open(&nd->path, MAY_OPEN, op->open_flag);
+ error = may_open(&path, MAY_OPEN, op->open_flag);
if (error)
goto out2;
- file->f_path.mnt = nd->path.mnt;
- error = finish_open(file, nd->path.dentry, NULL, opened);
+ file->f_path.mnt = path.mnt;
+ error = finish_open(file, child, NULL, opened);
if (error)
goto out2;
error = open_check_o_direct(file);
@@ -3309,9 +3305,9 @@ static int do_tmpfile(int dfd, struct filename *pathname,
spin_unlock(&inode->i_lock);
}
out2:
- mnt_drop_write(nd->path.mnt);
+ mnt_drop_write(path.mnt);
out:
- path_put(&nd->path);
+ path_put(&path);
return error;
}

--
2.1.4


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