Commit 90636e45 authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: create libxfs helper to remove an existing inode/name from a directory 



Create a new libxfs function to remove a (name, inode) entry from a
directory.  The upcoming metadata directory feature will need this to
create a metadata directory tree.

Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 1964435d

fs/xfs/libxfs/xfs_dir2.c

+81 −0
Original line number Diff line number Diff line
@@ -874,3 +874,84 @@ xfs_dir_add_child( 


	return 0;

}



/*

 * Given a directory @dp, a child @ip, and a @name, remove the (@name, @ip)

 * entry from the directory.  Both inodes must have the ILOCK held.

 */

int

xfs_dir_remove_child(

	struct xfs_trans	*tp,

	unsigned int		resblks,

	struct xfs_dir_update	*du)

{

	struct xfs_inode	*dp = du->dp;

	const struct xfs_name	*name = du->name;

	struct xfs_inode	*ip = du->ip;

	int			error;



	xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);

	xfs_assert_ilocked(dp, XFS_ILOCK_EXCL);



	/*

	 * If we're removing a directory perform some additional validation.

	 */

	if (S_ISDIR(VFS_I(ip)->i_mode)) {

		ASSERT(VFS_I(ip)->i_nlink >= 2);

		if (VFS_I(ip)->i_nlink != 2)

			return -ENOTEMPTY;

		if (!xfs_dir_isempty(ip))

			return -ENOTEMPTY;



		/* Drop the link from ip's "..".  */

		error = xfs_droplink(tp, dp);

		if (error)

			return error;



		/* Drop the "." link from ip to self.  */

		error = xfs_droplink(tp, ip);

		if (error)

			return error;



		/*

		 * Point the unlinked child directory's ".." entry to the root

		 * directory to eliminate back-references to inodes that may

		 * get freed before the child directory is closed.  If the fs

		 * gets shrunk, this can lead to dirent inode validation errors.

		 */

		if (dp->i_ino != tp->t_mountp->m_sb.sb_rootino) {

			error = xfs_dir_replace(tp, ip, &xfs_name_dotdot,

					tp->t_mountp->m_sb.sb_rootino, 0);

			if (error)

				return error;

		}

	} else {

		/*

		 * When removing a non-directory we need to log the parent

		 * inode here.  For a directory this is done implicitly

		 * by the xfs_droplink call for the ".." entry.

		 */

		xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);

	}

	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);



	/* Drop the link from dp to ip. */

	error = xfs_droplink(tp, ip);

	if (error)

		return error;



	error = xfs_dir_removename(tp, dp, name, ip->i_ino, resblks);

	if (error) {

		ASSERT(error != -ENOENT);

		return error;

	}



	/* Remove parent pointer. */

	if (du->ppargs) {

		error = xfs_parent_removename(tp, du->ppargs, dp, name, ip);

		if (error)

			return error;

	}



	return 0;

}

fs/xfs/libxfs/xfs_dir2.h

+2 −0
Original line number Diff line number Diff line
@@ -322,5 +322,7 @@ int xfs_dir_create_child(struct xfs_trans *tp, unsigned int resblks, 
		struct xfs_dir_update *du);

int xfs_dir_add_child(struct xfs_trans *tp, unsigned int resblks,

		struct xfs_dir_update *du);

int xfs_dir_remove_child(struct xfs_trans *tp, unsigned int resblks,

		struct xfs_dir_update *du);



#endif	/* __XFS_DIR2_H__ */

fs/xfs/xfs_inode.c

+9 −65
Original line number Diff line number Diff line
@@ -2040,13 +2040,17 @@ xfs_remove( 
	struct xfs_name		*name,

	struct xfs_inode	*ip)

{

	struct xfs_dir_update	du = {

		.dp		= dp,

		.name		= name,

		.ip		= ip,

	};

	struct xfs_mount	*mp = dp->i_mount;

	struct xfs_trans	*tp = NULL;

	int			is_dir = S_ISDIR(VFS_I(ip)->i_mode);

	int			dontcare;

	int                     error = 0;

	uint			resblks;

	struct xfs_parent_args	*ppargs;



	trace_xfs_remove(dp, name);
@@ -2063,7 +2067,7 @@ xfs_remove( 
	if (error)

		goto std_return;



	error = xfs_parent_start(mp, &ppargs);

	error = xfs_parent_start(mp, &du.ppargs);

	if (error)

		goto std_return;
@@ -2086,70 +2090,10 @@ xfs_remove( 
		goto out_parent;

	}



	/*

	 * If we're removing a directory perform some additional validation.

	 */

	if (is_dir) {

		ASSERT(VFS_I(ip)->i_nlink >= 2);

		if (VFS_I(ip)->i_nlink != 2) {

			error = -ENOTEMPTY;

			goto out_trans_cancel;

		}

		if (!xfs_dir_isempty(ip)) {

			error = -ENOTEMPTY;

			goto out_trans_cancel;

		}



		/* Drop the link from ip's "..".  */

		error = xfs_droplink(tp, dp);

		if (error)

			goto out_trans_cancel;



		/* Drop the "." link from ip to self.  */

		error = xfs_droplink(tp, ip);

		if (error)

			goto out_trans_cancel;



		/*

		 * Point the unlinked child directory's ".." entry to the root

		 * directory to eliminate back-references to inodes that may

		 * get freed before the child directory is closed.  If the fs

		 * gets shrunk, this can lead to dirent inode validation errors.

		 */

		if (dp->i_ino != tp->t_mountp->m_sb.sb_rootino) {

			error = xfs_dir_replace(tp, ip, &xfs_name_dotdot,

					tp->t_mountp->m_sb.sb_rootino, 0);

			if (error)

				goto out_trans_cancel;

		}

	} else {

		/*

		 * When removing a non-directory we need to log the parent

		 * inode here.  For a directory this is done implicitly

		 * by the xfs_droplink call for the ".." entry.

		 */

		xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);

	}

	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);



	/* Drop the link from dp to ip. */

	error = xfs_droplink(tp, ip);

	error = xfs_dir_remove_child(tp, resblks, &du);

	if (error)

		goto out_trans_cancel;



	error = xfs_dir_removename(tp, dp, name, ip->i_ino, resblks);

	if (error) {

		ASSERT(error != -ENOENT);

		goto out_trans_cancel;

	}



	/* Remove parent pointer. */

	if (ppargs) {

		error = xfs_parent_removename(tp, ppargs, dp, name, ip);

		if (error)

			goto out_trans_cancel;

	}



	/*

	 * Drop the link from dp to ip, and if ip was a directory, remove the

	 * '.' and '..' references since we freed the directory.
@@ -2173,7 +2117,7 @@ xfs_remove( 


	xfs_iunlock(ip, XFS_ILOCK_EXCL);

	xfs_iunlock(dp, XFS_ILOCK_EXCL);

	xfs_parent_finish(mp, ppargs);

	xfs_parent_finish(mp, du.ppargs);

	return 0;



 out_trans_cancel:
@@ -2182,7 +2126,7 @@ xfs_remove( 
	xfs_iunlock(ip, XFS_ILOCK_EXCL);

	xfs_iunlock(dp, XFS_ILOCK_EXCL);

 out_parent:

	xfs_parent_finish(mp, ppargs);

	xfs_parent_finish(mp, du.ppargs);

 std_return:

	return error;

}