1 files changed, 121 insertions, 43 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 44856b70ea3b..507ca0d7878d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1835,6 +1835,20 @@ static struct dentry *lookup_slow(const struct qstr *name,
 	return res;
 }
 
+static struct dentry *lookup_slow_killable(const struct qstr *name,
+					   struct dentry *dir,
+					   unsigned int flags)
+{
+	struct inode *inode = dir->d_inode;
+	struct dentry *res;
+
+	if (inode_lock_shared_killable(inode))
+		return ERR_PTR(-EINTR);
+	res = __lookup_slow(name, dir, flags);
+	inode_unlock_shared(inode);
+	return res;
+}
+
 static inline int may_lookup(struct mnt_idmap *idmap,
 			     struct nameidata *restrict nd)
 {
@@ -2752,7 +2766,8 @@ static int filename_parentat(int dfd, struct filename *name,
 }
 
 /* does lookup, returns the object with parent locked */
-static struct dentry *__kern_path_locked(int dfd, struct filename *name, struct path *path)
+static struct dentry *__start_removing_path(int dfd, struct filename *name,
+					   struct path *path)
 {
 	struct path parent_path __free(path_put) = {};
 	struct dentry *d;
@@ -2764,18 +2779,42 @@ static struct dentry *__kern_path_locked(int dfd, struct filename *name, struct
 		return ERR_PTR(error);
 	if (unlikely(type != LAST_NORM))
 		return ERR_PTR(-EINVAL);
+	/* don't fail immediately if it's r/o, at least try to report other errors */
+	error = mnt_want_write(parent_path.mnt);
 	inode_lock_nested(parent_path.dentry->d_inode, I_MUTEX_PARENT);
 	d = lookup_one_qstr_excl(&last, parent_path.dentry, 0);
-	if (IS_ERR(d)) {
-		inode_unlock(parent_path.dentry->d_inode);
-		return d;
-	}
+	if (IS_ERR(d))
+		goto unlock;
+	if (error)
+		goto fail;
 	path->dentry = no_free_ptr(parent_path.dentry);
 	path->mnt = no_free_ptr(parent_path.mnt);
 	return d;
+
+fail:
+	dput(d);
+	d = ERR_PTR(error);
+unlock:
+	inode_unlock(parent_path.dentry->d_inode);
+	if (!error)
+		mnt_drop_write(parent_path.mnt);
+	return d;
 }
 
-struct dentry *kern_path_locked_negative(const char *name, struct path *path)
+/**
+ * kern_path_parent: lookup path returning parent and target
+ * @name: path name
+ * @path: path to store parent in
+ *
+ * The path @name should end with a normal component, not "." or ".." or "/".
+ * A lookup is performed and if successful the parent information
+ * is store in @parent and the dentry is returned.
+ *
+ * The dentry maybe negative, the parent will be positive.
+ *
+ * Returns:  dentry or error.
+ */
+struct dentry *kern_path_parent(const char *name, struct path *path)
 {
 	struct path parent_path __free(path_put) = {};
 	struct filename *filename __free(putname) = getname_kernel(name);
@@ -2788,35 +2827,35 @@ struct dentry *kern_path_locked_negative(const char *name, struct path *path)
 		return ERR_PTR(error);
 	if (unlikely(type != LAST_NORM))
 		return ERR_PTR(-EINVAL);
-	inode_lock_nested(parent_path.dentry->d_inode, I_MUTEX_PARENT);
-	d = lookup_one_qstr_excl(&last, parent_path.dentry, LOOKUP_CREATE);
-	if (IS_ERR(d)) {
-		inode_unlock(parent_path.dentry->d_inode);
+
+	d = lookup_noperm_unlocked(&last, parent_path.dentry);
+	if (IS_ERR(d))
 		return d;
-	}
 	path->dentry = no_free_ptr(parent_path.dentry);
 	path->mnt = no_free_ptr(parent_path.mnt);
 	return d;
 }
 
-struct dentry *kern_path_locked(const char *name, struct path *path)
+struct dentry *start_removing_path(const char *name, struct path *path)
 {
 	struct filename *filename = getname_kernel(name);
-	struct dentry *res = __kern_path_locked(AT_FDCWD, filename, path);
+	struct dentry *res = __start_removing_path(AT_FDCWD, filename, path);
 
 	putname(filename);
 	return res;
 }
 
-struct dentry *user_path_locked_at(int dfd, const char __user *name, struct path *path)
+struct dentry *start_removing_user_path_at(int dfd,
+					   const char __user *name,
+					   struct path *path)
 {
 	struct filename *filename = getname(name);
-	struct dentry *res = __kern_path_locked(dfd, filename, path);
+	struct dentry *res = __start_removing_path(dfd, filename, path);
 
 	putname(filename);
 	return res;
 }
-EXPORT_SYMBOL(user_path_locked_at);
+EXPORT_SYMBOL(start_removing_user_path_at);
 
 int kern_path(const char *name, unsigned int flags, struct path *path)
 {
@@ -3019,6 +3058,47 @@ struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap, struct qstr *name,
 EXPORT_SYMBOL(lookup_one_unlocked);
 
 /**
+ * lookup_one_positive_killable - lookup single pathname component
+ * @idmap:	idmap of the mount the lookup is performed from
+ * @name:	qstr olding pathname component to lookup
+ * @base:	base directory to lookup from
+ *
+ * This helper will yield ERR_PTR(-ENOENT) on negatives. The helper returns
+ * known positive or ERR_PTR(). This is what most of the users want.
+ *
+ * Note that pinned negative with unlocked parent _can_ become positive at any
+ * time, so callers of lookup_one_unlocked() need to be very careful; pinned
+ * positives have >d_inode stable, so this one avoids such problems.
+ *
+ * This can be used for in-kernel filesystem clients such as file servers.
+ *
+ * It should be called without the parent i_rwsem held, and will take
+ * the i_rwsem itself if necessary.  If a fatal signal is pending or
+ * delivered, it will return %-EINTR if the lock is needed.
+ */
+struct dentry *lookup_one_positive_killable(struct mnt_idmap *idmap,
+					    struct qstr *name,
+					    struct dentry *base)
+{
+	int err;
+	struct dentry *ret;
+
+	err = lookup_one_common(idmap, name, base);
+	if (err)
+		return ERR_PTR(err);
+
+	ret = lookup_dcache(name, base, 0);
+	if (!ret)
+		ret = lookup_slow_killable(name, base, 0);
+	if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) {
+		dput(ret);
+		ret = ERR_PTR(-ENOENT);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(lookup_one_positive_killable);
+
+/**
  * lookup_one_positive_unlocked - lookup single pathname component
  * @idmap:	idmap of the mount the lookup is performed from
  * @name:	qstr holding pathname component to lookup
@@ -4122,7 +4202,6 @@ static struct dentry *filename_create(int dfd, struct filename *name,
 	unsigned int reval_flag = lookup_flags & LOOKUP_REVAL;
 	unsigned int create_flags = LOOKUP_CREATE | LOOKUP_EXCL;
 	int type;
-	int err2;
 	int error;
 
 	error = filename_parentat(dfd, name, reval_flag, path, &last, &type);
@@ -4137,7 +4216,7 @@ static struct dentry *filename_create(int dfd, struct filename *name,
 		goto out;
 
 	/* don't fail immediately if it's r/o, at least try to report other errors */
-	err2 = mnt_want_write(path->mnt);
+	error = mnt_want_write(path->mnt);
 	/*
 	 * Do the final lookup.  Suppress 'create' if there is a trailing
 	 * '/', and a directory wasn't requested.
@@ -4150,25 +4229,24 @@ static struct dentry *filename_create(int dfd, struct filename *name,
 	if (IS_ERR(dentry))
 		goto unlock;
 
-	if (unlikely(err2)) {
-		error = err2;
+	if (unlikely(error))
 		goto fail;
-	}
+
 	return dentry;
 fail:
 	dput(dentry);
 	dentry = ERR_PTR(error);
 unlock:
 	inode_unlock(path->dentry->d_inode);
-	if (!err2)
+	if (!error)
 		mnt_drop_write(path->mnt);
 out:
 	path_put(path);
 	return dentry;
 }
 
-struct dentry *kern_path_create(int dfd, const char *pathname,
-				struct path *path, unsigned int lookup_flags)
+struct dentry *start_creating_path(int dfd, const char *pathname,
+				   struct path *path, unsigned int lookup_flags)
 {
 	struct filename *filename = getname_kernel(pathname);
 	struct dentry *res = filename_create(dfd, filename, path, lookup_flags);
@@ -4176,9 +4254,9 @@ struct dentry *kern_path_create(int dfd, const char *pathname,
 	putname(filename);
 	return res;
 }
-EXPORT_SYMBOL(kern_path_create);
+EXPORT_SYMBOL(start_creating_path);
 
-void done_path_create(struct path *path, struct dentry *dentry)
+void end_creating_path(struct path *path, struct dentry *dentry)
 {
 	if (!IS_ERR(dentry))
 		dput(dentry);
@@ -4186,10 +4264,11 @@ void done_path_create(struct path *path, struct dentry *dentry)
 	mnt_drop_write(path->mnt);
 	path_put(path);
 }
-EXPORT_SYMBOL(done_path_create);
+EXPORT_SYMBOL(end_creating_path);
 
-inline struct dentry *user_path_create(int dfd, const char __user *pathname,
-				struct path *path, unsigned int lookup_flags)
+inline struct dentry *start_creating_user_path(
+	int dfd, const char __user *pathname,
+	struct path *path, unsigned int lookup_flags)
 {
 	struct filename *filename = getname(pathname);
 	struct dentry *res = filename_create(dfd, filename, path, lookup_flags);
@@ -4197,7 +4276,7 @@ inline struct dentry *user_path_create(int dfd, const char __user *pathname,
 	putname(filename);
 	return res;
 }
-EXPORT_SYMBOL(user_path_create);
+EXPORT_SYMBOL(start_creating_user_path);
 
 /**
  * vfs_mknod - create device node or file
@@ -4305,7 +4384,7 @@ retry:
 			break;
 	}
 out2:
-	done_path_create(&path, dentry);
+	end_creating_path(&path, dentry);
 	if (retry_estale(error, lookup_flags)) {
 		lookup_flags |= LOOKUP_REVAL;
 		goto retry;
@@ -4409,7 +4488,7 @@ retry:
 		if (IS_ERR(dentry))
 			error = PTR_ERR(dentry);
 	}
-	done_path_create(&path, dentry);
+	end_creating_path(&path, dentry);
 	if (retry_estale(error, lookup_flags)) {
 		lookup_flags |= LOOKUP_REVAL;
 		goto retry;
@@ -4763,7 +4842,7 @@ retry:
 	if (!error)
 		error = vfs_symlink(mnt_idmap(path.mnt), path.dentry->d_inode,
 				    dentry, from->name);
-	done_path_create(&path, dentry);
+	end_creating_path(&path, dentry);
 	if (retry_estale(error, lookup_flags)) {
 		lookup_flags |= LOOKUP_REVAL;
 		goto retry;
@@ -4932,7 +5011,7 @@ retry:
 	error = vfs_link(old_path.dentry, idmap, new_path.dentry->d_inode,
 			 new_dentry, &delegated_inode);
 out_dput:
-	done_path_create(&new_path, new_dentry);
+	end_creating_path(&new_path, new_dentry);
 	if (delegated_inode) {
 		error = break_deleg_wait(&delegated_inode);
 		if (!error) {
@@ -5032,20 +5111,20 @@ int vfs_rename(struct renamedata *rd)
 	if (source == target)
 		return 0;
 
-	error = may_delete(rd->old_mnt_idmap, old_dir, old_dentry, is_dir);
+	error = may_delete(rd->mnt_idmap, old_dir, old_dentry, is_dir);
 	if (error)
 		return error;
 
 	if (!target) {
-		error = may_create(rd->new_mnt_idmap, new_dir, new_dentry);
+		error = may_create(rd->mnt_idmap, new_dir, new_dentry);
 	} else {
 		new_is_dir = d_is_dir(new_dentry);
 
 		if (!(flags & RENAME_EXCHANGE))
-			error = may_delete(rd->new_mnt_idmap, new_dir,
+			error = may_delete(rd->mnt_idmap, new_dir,
 					   new_dentry, is_dir);
 		else
-			error = may_delete(rd->new_mnt_idmap, new_dir,
+			error = may_delete(rd->mnt_idmap, new_dir,
 					   new_dentry, new_is_dir);
 	}
 	if (error)
@@ -5060,13 +5139,13 @@ int vfs_rename(struct renamedata *rd)
 	 */
 	if (new_dir != old_dir) {
 		if (is_dir) {
-			error = inode_permission(rd->old_mnt_idmap, source,
+			error = inode_permission(rd->mnt_idmap, source,
 						 MAY_WRITE);
 			if (error)
 				return error;
 		}
 		if ((flags & RENAME_EXCHANGE) && new_is_dir) {
-			error = inode_permission(rd->new_mnt_idmap, target,
+			error = inode_permission(rd->mnt_idmap, target,
 						 MAY_WRITE);
 			if (error)
 				return error;
@@ -5134,7 +5213,7 @@ int vfs_rename(struct renamedata *rd)
 		if (error)
 			goto out;
 	}
-	error = old_dir->i_op->rename(rd->new_mnt_idmap, old_dir, old_dentry,
+	error = old_dir->i_op->rename(rd->mnt_idmap, old_dir, old_dentry,
 				      new_dir, new_dentry, flags);
 	if (error)
 		goto out;
@@ -5277,10 +5356,9 @@ retry_deleg:
 
 	rd.old_parent	   = old_path.dentry;
 	rd.old_dentry	   = old_dentry;
-	rd.old_mnt_idmap   = mnt_idmap(old_path.mnt);
+	rd.mnt_idmap	   = mnt_idmap(old_path.mnt);
 	rd.new_parent	   = new_path.dentry;
 	rd.new_dentry	   = new_dentry;
-	rd.new_mnt_idmap   = mnt_idmap(new_path.mnt);
 	rd.delegated_inode = &delegated_inode;
 	rd.flags	   = flags;
 	error = vfs_rename(&rd);