name: shift nameidata down into user_path_walk()
that avoids having nameidata on stack during the calls of ->rmdir()/->unlink() and *two* of those during the calls of ->rename(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
parent
6a9f40d610
commit
f5beed755b
124
fs/namei.c
124
fs/namei.c
@ -2211,9 +2211,13 @@ EXPORT_SYMBOL(user_path_at);
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* path-walking is complete.
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*/
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static struct filename *
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user_path_parent(int dfd, const char __user *path, struct nameidata *nd,
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user_path_parent(int dfd, const char __user *path,
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struct path *parent,
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struct qstr *last,
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int *type,
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unsigned int flags)
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{
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struct nameidata nd;
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struct filename *s = getname(path);
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int error;
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@ -2223,11 +2227,14 @@ user_path_parent(int dfd, const char __user *path, struct nameidata *nd,
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if (IS_ERR(s))
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return s;
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error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, nd);
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error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, &nd);
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if (error) {
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putname(s);
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return ERR_PTR(error);
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}
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*parent = nd.path;
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*last = nd.last;
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*type = nd.last_type;
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return s;
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}
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@ -3630,14 +3637,17 @@ static long do_rmdir(int dfd, const char __user *pathname)
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int error = 0;
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struct filename *name;
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struct dentry *dentry;
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struct nameidata nd;
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struct path path;
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struct qstr last;
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int type;
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unsigned int lookup_flags = 0;
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retry:
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name = user_path_parent(dfd, pathname, &nd, lookup_flags);
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name = user_path_parent(dfd, pathname,
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&path, &last, &type, lookup_flags);
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if (IS_ERR(name))
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return PTR_ERR(name);
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switch(nd.last_type) {
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switch (type) {
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case LAST_DOTDOT:
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error = -ENOTEMPTY;
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goto exit1;
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@ -3649,13 +3659,12 @@ retry:
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goto exit1;
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}
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nd.flags &= ~LOOKUP_PARENT;
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error = mnt_want_write(nd.path.mnt);
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error = mnt_want_write(path.mnt);
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if (error)
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goto exit1;
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mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
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dentry = __lookup_hash(&nd.last, nd.path.dentry, nd.flags);
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mutex_lock_nested(&path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
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dentry = __lookup_hash(&last, path.dentry, lookup_flags);
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error = PTR_ERR(dentry);
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if (IS_ERR(dentry))
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goto exit2;
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@ -3663,17 +3672,17 @@ retry:
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error = -ENOENT;
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goto exit3;
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}
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error = security_path_rmdir(&nd.path, dentry);
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error = security_path_rmdir(&path, dentry);
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if (error)
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goto exit3;
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error = vfs_rmdir(nd.path.dentry->d_inode, dentry);
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error = vfs_rmdir(path.dentry->d_inode, dentry);
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exit3:
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dput(dentry);
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exit2:
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mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
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mnt_drop_write(nd.path.mnt);
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mutex_unlock(&path.dentry->d_inode->i_mutex);
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mnt_drop_write(path.mnt);
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exit1:
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path_put(&nd.path);
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path_put(&path);
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putname(name);
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if (retry_estale(error, lookup_flags)) {
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lookup_flags |= LOOKUP_REVAL;
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@ -3756,43 +3765,45 @@ static long do_unlinkat(int dfd, const char __user *pathname)
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int error;
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struct filename *name;
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struct dentry *dentry;
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struct nameidata nd;
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struct path path;
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struct qstr last;
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int type;
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struct inode *inode = NULL;
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struct inode *delegated_inode = NULL;
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unsigned int lookup_flags = 0;
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retry:
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name = user_path_parent(dfd, pathname, &nd, lookup_flags);
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name = user_path_parent(dfd, pathname,
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&path, &last, &type, lookup_flags);
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if (IS_ERR(name))
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return PTR_ERR(name);
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error = -EISDIR;
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if (nd.last_type != LAST_NORM)
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if (type != LAST_NORM)
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goto exit1;
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nd.flags &= ~LOOKUP_PARENT;
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error = mnt_want_write(nd.path.mnt);
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error = mnt_want_write(path.mnt);
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if (error)
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goto exit1;
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retry_deleg:
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mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
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dentry = __lookup_hash(&nd.last, nd.path.dentry, nd.flags);
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mutex_lock_nested(&path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
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dentry = __lookup_hash(&last, path.dentry, lookup_flags);
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error = PTR_ERR(dentry);
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if (!IS_ERR(dentry)) {
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/* Why not before? Because we want correct error value */
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if (nd.last.name[nd.last.len])
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if (last.name[last.len])
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goto slashes;
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inode = dentry->d_inode;
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if (d_is_negative(dentry))
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goto slashes;
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ihold(inode);
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error = security_path_unlink(&nd.path, dentry);
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error = security_path_unlink(&path, dentry);
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if (error)
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goto exit2;
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error = vfs_unlink(nd.path.dentry->d_inode, dentry, &delegated_inode);
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error = vfs_unlink(path.dentry->d_inode, dentry, &delegated_inode);
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exit2:
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dput(dentry);
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}
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mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
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mutex_unlock(&path.dentry->d_inode->i_mutex);
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if (inode)
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iput(inode); /* truncate the inode here */
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inode = NULL;
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@ -3801,9 +3812,9 @@ exit2:
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if (!error)
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goto retry_deleg;
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}
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mnt_drop_write(nd.path.mnt);
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mnt_drop_write(path.mnt);
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exit1:
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path_put(&nd.path);
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path_put(&path);
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putname(name);
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if (retry_estale(error, lookup_flags)) {
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lookup_flags |= LOOKUP_REVAL;
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@ -4233,14 +4244,15 @@ EXPORT_SYMBOL(vfs_rename);
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SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
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int, newdfd, const char __user *, newname, unsigned int, flags)
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{
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struct dentry *old_dir, *new_dir;
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struct dentry *old_dentry, *new_dentry;
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struct dentry *trap;
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struct nameidata oldnd, newnd;
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struct path old_path, new_path;
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struct qstr old_last, new_last;
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int old_type, new_type;
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struct inode *delegated_inode = NULL;
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struct filename *from;
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struct filename *to;
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unsigned int lookup_flags = 0;
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unsigned int lookup_flags = 0, target_flags = LOOKUP_RENAME_TARGET;
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bool should_retry = false;
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int error;
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@ -4254,47 +4266,45 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
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if ((flags & RENAME_WHITEOUT) && !capable(CAP_MKNOD))
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return -EPERM;
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if (flags & RENAME_EXCHANGE)
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target_flags = 0;
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retry:
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from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags);
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from = user_path_parent(olddfd, oldname,
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&old_path, &old_last, &old_type, lookup_flags);
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if (IS_ERR(from)) {
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error = PTR_ERR(from);
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goto exit;
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}
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to = user_path_parent(newdfd, newname, &newnd, lookup_flags);
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to = user_path_parent(newdfd, newname,
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&new_path, &new_last, &new_type, lookup_flags);
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if (IS_ERR(to)) {
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error = PTR_ERR(to);
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goto exit1;
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}
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error = -EXDEV;
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if (oldnd.path.mnt != newnd.path.mnt)
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if (old_path.mnt != new_path.mnt)
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goto exit2;
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old_dir = oldnd.path.dentry;
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error = -EBUSY;
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if (oldnd.last_type != LAST_NORM)
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if (old_type != LAST_NORM)
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goto exit2;
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new_dir = newnd.path.dentry;
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if (flags & RENAME_NOREPLACE)
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error = -EEXIST;
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if (newnd.last_type != LAST_NORM)
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if (new_type != LAST_NORM)
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goto exit2;
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error = mnt_want_write(oldnd.path.mnt);
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error = mnt_want_write(old_path.mnt);
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if (error)
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goto exit2;
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oldnd.flags &= ~LOOKUP_PARENT;
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newnd.flags &= ~LOOKUP_PARENT;
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if (!(flags & RENAME_EXCHANGE))
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newnd.flags |= LOOKUP_RENAME_TARGET;
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retry_deleg:
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trap = lock_rename(new_dir, old_dir);
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trap = lock_rename(new_path.dentry, old_path.dentry);
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old_dentry = __lookup_hash(&oldnd.last, oldnd.path.dentry, oldnd.flags);
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old_dentry = __lookup_hash(&old_last, old_path.dentry, lookup_flags);
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error = PTR_ERR(old_dentry);
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if (IS_ERR(old_dentry))
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goto exit3;
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@ -4302,7 +4312,7 @@ retry_deleg:
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error = -ENOENT;
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if (d_is_negative(old_dentry))
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goto exit4;
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new_dentry = __lookup_hash(&newnd.last, newnd.path.dentry, newnd.flags);
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new_dentry = __lookup_hash(&new_last, new_path.dentry, lookup_flags | target_flags);
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error = PTR_ERR(new_dentry);
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if (IS_ERR(new_dentry))
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goto exit4;
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@ -4316,16 +4326,16 @@ retry_deleg:
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if (!d_is_dir(new_dentry)) {
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error = -ENOTDIR;
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if (newnd.last.name[newnd.last.len])
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if (new_last.name[new_last.len])
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goto exit5;
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}
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}
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/* unless the source is a directory trailing slashes give -ENOTDIR */
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if (!d_is_dir(old_dentry)) {
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error = -ENOTDIR;
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if (oldnd.last.name[oldnd.last.len])
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if (old_last.name[old_last.len])
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goto exit5;
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if (!(flags & RENAME_EXCHANGE) && newnd.last.name[newnd.last.len])
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if (!(flags & RENAME_EXCHANGE) && new_last.name[new_last.len])
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goto exit5;
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}
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/* source should not be ancestor of target */
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@ -4338,32 +4348,32 @@ retry_deleg:
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if (new_dentry == trap)
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goto exit5;
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error = security_path_rename(&oldnd.path, old_dentry,
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&newnd.path, new_dentry, flags);
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error = security_path_rename(&old_path, old_dentry,
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&new_path, new_dentry, flags);
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if (error)
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goto exit5;
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error = vfs_rename(old_dir->d_inode, old_dentry,
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new_dir->d_inode, new_dentry,
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error = vfs_rename(old_path.dentry->d_inode, old_dentry,
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new_path.dentry->d_inode, new_dentry,
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&delegated_inode, flags);
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exit5:
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dput(new_dentry);
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exit4:
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dput(old_dentry);
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exit3:
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unlock_rename(new_dir, old_dir);
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unlock_rename(new_path.dentry, old_path.dentry);
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if (delegated_inode) {
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error = break_deleg_wait(&delegated_inode);
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if (!error)
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goto retry_deleg;
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}
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mnt_drop_write(oldnd.path.mnt);
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mnt_drop_write(old_path.mnt);
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exit2:
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if (retry_estale(error, lookup_flags))
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should_retry = true;
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path_put(&newnd.path);
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path_put(&new_path);
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putname(to);
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exit1:
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path_put(&oldnd.path);
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path_put(&old_path);
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putname(from);
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if (should_retry) {
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should_retry = false;
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