Commit 40dbd071 authored by Al Viro's avatar Al Viro
Browse files

ext4: don't access the source subdirectory content on same-directory rename 



We can't really afford locking the source on same-directory rename;
currently vfs_rename() tries to do that, but it will have to be changed.
The logics in ext4 is lazy and goes looking for ".." in source even in
same-directory case.  It's not hard to get rid of that, leaving that
behaviour only for cross-directory case; that VFS can get locks safely
(and will keep doing that after the coming changes).

Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 7307b73f

fs/ext4/namei.c

+13 −8
Original line number Diff line number Diff line
@@ -3591,10 +3591,14 @@ struct ext4_renament { 
	int dir_inlined;

};



static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)

static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent, bool is_cross)

{

	int retval;



	ent->is_dir = true;

	if (!is_cross)

		return 0;



	ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,

					      &retval, &ent->parent_de,

					      &ent->dir_inlined);
@@ -3612,6 +3616,9 @@ static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent, 
{

	int retval;



	if (!ent->dir_bh)

		return 0;



	ent->parent_de->inode = cpu_to_le32(dir_ino);

	BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");

	if (!ent->dir_inlined) {
@@ -3900,7 +3907,7 @@ static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir, 
			if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))

				goto end_rename;

		}

		retval = ext4_rename_dir_prepare(handle, &old);

		retval = ext4_rename_dir_prepare(handle, &old, new.dir != old.dir);

		if (retval)

			goto end_rename;

	}
@@ -3964,7 +3971,7 @@ static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir, 
	}

	inode_set_mtime_to_ts(old.dir, inode_set_ctime_current(old.dir));

	ext4_update_dx_flag(old.dir);

	if (old.dir_bh) {

	if (old.is_dir) {

		retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);

		if (retval)

			goto end_rename;
@@ -3987,7 +3994,7 @@ static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir, 
	if (unlikely(retval))

		goto end_rename;



	if (S_ISDIR(old.inode->i_mode)) {

	if (old.is_dir) {

		/*

		 * We disable fast commits here that's because the

		 * replay code is not yet capable of changing dot dot
@@ -4114,14 +4121,12 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry, 
		ext4_handle_sync(handle);



	if (S_ISDIR(old.inode->i_mode)) {

		old.is_dir = true;

		retval = ext4_rename_dir_prepare(handle, &old);

		retval = ext4_rename_dir_prepare(handle, &old, new.dir != old.dir);

		if (retval)

			goto end_rename;

	}

	if (S_ISDIR(new.inode->i_mode)) {

		new.is_dir = true;

		retval = ext4_rename_dir_prepare(handle, &new);

		retval = ext4_rename_dir_prepare(handle, &new, new.dir != old.dir);

		if (retval)

			goto end_rename;

	}