Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 30ee052e authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dave Chinner
Browse files

xfs: optimize inline symlinks 



By overallocating the in-core inode fork data buffer and zero
terminating the link target in xfs_init_local_fork we can avoid
the memory allocation in ->follow_link.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent bfe8804d

fs/xfs/libxfs/xfs_inode_fork.c

+18 −4
Original line number Diff line number Diff line
@@ -239,19 +239,33 @@ xfs_init_local_fork( 
	int			size)

{

	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);

	int			real_size = 0;

	int			mem_size = size, real_size = 0;

	bool			zero_terminate;



	/*

	 * If we are using the local fork to store a symlink body we need to

	 * zero-terminate it so that we can pass it back to the VFS directly.

	 * Overallocate the in-memory fork by one for that and add a zero

	 * to terminate it below.

	 */

	zero_terminate = S_ISLNK(VFS_I(ip)->i_mode);

	if (zero_terminate)

		mem_size++;



	if (size == 0)

		ifp->if_u1.if_data = NULL;

	else if (size <= sizeof(ifp->if_u2.if_inline_data))

	else if (mem_size <= sizeof(ifp->if_u2.if_inline_data))

		ifp->if_u1.if_data = ifp->if_u2.if_inline_data;

	else {

		real_size = roundup(size, 4);

		real_size = roundup(mem_size, 4);

		ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP | KM_NOFS);

	}



	if (size)

	if (size) {

		memcpy(ifp->if_u1.if_data, data, size);

		if (zero_terminate)

			ifp->if_u1.if_data[size] = '\0';

	}



	ifp->if_bytes = size;

	ifp->if_real_bytes = real_size;

fs/xfs/xfs_inode_item.c

+2 −2
Original line number Diff line number Diff line
@@ -210,7 +210,7 @@ xfs_inode_item_format_data_fork( 
			 */

			data_bytes = roundup(ip->i_df.if_bytes, 4);

			ASSERT(ip->i_df.if_real_bytes == 0 ||

			       ip->i_df.if_real_bytes == data_bytes);

			       ip->i_df.if_real_bytes >= data_bytes);

			ASSERT(ip->i_df.if_u1.if_data != NULL);

			ASSERT(ip->i_d.di_size > 0);

			xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_ILOCAL,
@@ -305,7 +305,7 @@ xfs_inode_item_format_attr_fork( 
			 */

			data_bytes = roundup(ip->i_afp->if_bytes, 4);

			ASSERT(ip->i_afp->if_real_bytes == 0 ||

			       ip->i_afp->if_real_bytes == data_bytes);

			       ip->i_afp->if_real_bytes >= data_bytes);

			ASSERT(ip->i_afp->if_u1.if_data != NULL);

			xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_IATTR_LOCAL,

					ip->i_afp->if_u1.if_data,

fs/xfs/xfs_iops.c

+26 −3
Original line number Diff line number Diff line
@@ -446,6 +446,16 @@ xfs_vn_get_link( 
	return ERR_PTR(error);

}



STATIC const char *

xfs_vn_get_link_inline(

	struct dentry		*dentry,

	struct inode		*inode,

	struct delayed_call	*done)

{

	ASSERT(XFS_I(inode)->i_df.if_flags & XFS_IFINLINE);

	return XFS_I(inode)->i_df.if_u1.if_data;

}



STATIC int

xfs_vn_getattr(

	struct vfsmount		*mnt,
@@ -1171,6 +1181,18 @@ static const struct inode_operations xfs_symlink_inode_operations = { 
	.update_time		= xfs_vn_update_time,

};



static const struct inode_operations xfs_inline_symlink_inode_operations = {

	.readlink		= generic_readlink,

	.get_link		= xfs_vn_get_link_inline,

	.getattr		= xfs_vn_getattr,

	.setattr		= xfs_vn_setattr,

	.setxattr		= generic_setxattr,

	.getxattr		= generic_getxattr,

	.removexattr		= generic_removexattr,

	.listxattr		= xfs_vn_listxattr,

	.update_time		= xfs_vn_update_time,

};



STATIC void

xfs_diflags_to_iflags(

	struct inode		*inode,
@@ -1282,9 +1304,10 @@ xfs_setup_iops( 
		inode->i_fop = &xfs_dir_file_operations;

		break;

	case S_IFLNK:

		if (ip->i_df.if_flags & XFS_IFINLINE)

			inode->i_op = &xfs_inline_symlink_inode_operations;

		else

			inode->i_op = &xfs_symlink_inode_operations;

		if (!(ip->i_df.if_flags & XFS_IFINLINE))

			inode->i_mapping->a_ops = &xfs_address_space_operations;

		break;

	default:

		inode->i_op = &xfs_inode_operations;

fs/xfs/xfs_symlink.c

+3 −6
Original line number Diff line number Diff line
@@ -131,6 +131,8 @@ xfs_readlink( 


	trace_xfs_readlink(ip);



	ASSERT(!(ip->i_df.if_flags & XFS_IFINLINE));



	if (XFS_FORCED_SHUTDOWN(mp))

		return -EIO;
@@ -150,12 +152,7 @@ xfs_readlink( 
	}





	if (ip->i_df.if_flags & XFS_IFINLINE) {

		memcpy(link, ip->i_df.if_u1.if_data, pathlen);

		link[pathlen] = '\0';

	} else {

	error = xfs_readlink_bmap(ip, link);

	}



 out:

	xfs_iunlock(ip, XFS_ILOCK_SHARED);