xfs: create libxfs helper to link a new inode into a directory

Create a new libxfs function to link a newly created inode into a
directory.  The upcoming metadata directory feature will need this to
create a metadata directory tree.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/libxfs/xfs_dir2.c

@@ -19,6 +19,9 @@
 #include "xfs_error.h"
 #include "xfs_trace.h"
 #include "xfs_health.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_trans_space.h"
+#include "xfs_parent.h"
 
 const struct xfs_name xfs_name_dotdot = {
 	.name	= (const unsigned char *)"..",
@@ -756,3 +759,53 @@ xfs_dir2_compname(
 		return xfs_ascii_ci_compname(args, name, len);
 	return xfs_da_compname(args, name, len);
 }
+
+/*
+ * Given a directory @dp, a newly allocated inode @ip, and a @name, link @ip
+ * into @dp under the given @name.  If @ip is a directory, it will be
+ * initialized.  Both inodes must have the ILOCK held and the transaction must
+ * have sufficient blocks reserved.
+ */
+int
+xfs_dir_create_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);
+
+	error = xfs_dir_createname(tp, dp, name, ip->i_ino, resblks);
+	if (error) {
+		ASSERT(error != -ENOSPC);
+		return error;
+	}
+
+	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
+	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
+
+	if (S_ISDIR(VFS_I(ip)->i_mode)) {
+		error = xfs_dir_init(tp, ip, dp);
+		if (error)
+			return error;
+
+		xfs_bumplink(tp, dp);
+	}
+
+	/*
+	 * If we have parent pointers, we need to add the attribute containing
+	 * the parent information now.
+	 */
+	if (du->ppargs) {
+		error = xfs_parent_addname(tp, du->ppargs, dp, name, ip);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}

fs/xfs/libxfs/xfs_dir2.h

@@ -309,4 +309,16 @@ static inline unsigned char xfs_ascii_ci_xfrm(unsigned char c)
 	return c;
 }
 
+struct xfs_parent_args;
+
+struct xfs_dir_update {
+	struct xfs_inode	*dp;
+	const struct xfs_name	*name;
+	struct xfs_inode	*ip;
+	struct xfs_parent_args	*ppargs;
+};
+
+int xfs_dir_create_child(struct xfs_trans *tp, unsigned int resblks,
+		struct xfs_dir_update *du);
+
 #endif	/* __XFS_DIR2_H__ */

fs/xfs/xfs_inode.c

@@ -714,14 +714,16 @@ xfs_create(
 	struct xfs_inode	**ipp)
 {
 	struct xfs_inode	*dp = args->pip;
+	struct xfs_dir_update	du = {
+		.dp		= dp,
+		.name		= name,
+	};
 	struct xfs_mount	*mp = dp->i_mount;
-	struct xfs_inode	*ip = NULL;
 	struct xfs_trans	*tp = NULL;
 	struct xfs_dquot	*udqp;
 	struct xfs_dquot	*gdqp;
 	struct xfs_dquot	*pdqp;
 	struct xfs_trans_res	*tres;
-	struct xfs_parent_args	*ppargs;
 	xfs_ino_t		ino;
 	bool			unlock_dp_on_error = false;
 	bool			is_dir = S_ISDIR(args->mode);
@@ -748,7 +750,7 @@ xfs_create(
 		tres = &M_RES(mp)->tr_create;
 	}
 
-	error = xfs_parent_start(mp, &ppargs);
+	error = xfs_parent_start(mp, &du.ppargs);
 	if (error)
 		goto out_release_dquots;
 
@@ -779,7 +781,7 @@ xfs_create(
 	 */
 	error = xfs_dialloc(&tp, dp->i_ino, args->mode, &ino);
 	if (!error)
-		error = xfs_icreate(tp, ino, args, &ip);
+		error = xfs_icreate(tp, ino, args, &du.ip);
 	if (error)
 		goto out_trans_cancel;
 
@@ -792,38 +794,15 @@ xfs_create(
 	 */
 	xfs_trans_ijoin(tp, dp, 0);
 
-	error = xfs_dir_createname(tp, dp, name, ip->i_ino,
-					resblks - XFS_IALLOC_SPACE_RES(mp));
-	if (error) {
-		ASSERT(error != -ENOSPC);
+	error = xfs_dir_create_child(tp, resblks, &du);
+	if (error)
 		goto out_trans_cancel;
-	}
-	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
-	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
-
-	if (is_dir) {
-		error = xfs_dir_init(tp, ip, dp);
-		if (error)
-			goto out_trans_cancel;
-
-		xfs_bumplink(tp, dp);
-	}
-
-	/*
-	 * If we have parent pointers, we need to add the attribute containing
-	 * the parent information now.
-	 */
-	if (ppargs) {
-		error = xfs_parent_addname(tp, ppargs, dp, name, ip);
-		if (error)
-			goto out_trans_cancel;
-	}
 
 	/*
 	 * Create ip with a reference from dp, and add '.' and '..' references
 	 * if it's a directory.
 	 */
-	xfs_dir_update_hook(dp, ip, 1, name);
+	xfs_dir_update_hook(dp, du.ip, 1, name);
 
 	/*
 	 * If this is a synchronous mount, make sure that the
@@ -838,7 +817,7 @@ xfs_create(
 	 * These ids of the inode couldn't have changed since the new
 	 * inode has been locked ever since it was created.
 	 */
-	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
+	xfs_qm_vop_create_dqattach(tp, du.ip, udqp, gdqp, pdqp);
 
 	error = xfs_trans_commit(tp);
 	if (error)
@@ -848,10 +827,10 @@ xfs_create(
 	xfs_qm_dqrele(gdqp);
 	xfs_qm_dqrele(pdqp);
 
-	*ipp = ip;
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	*ipp = du.ip;
+	xfs_iunlock(du.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:
@@ -862,13 +841,13 @@ xfs_create(
 	 * setup of the inode and release the inode.  This prevents recursive
 	 * transactions and deadlocks from xfs_inactive.
 	 */
-	if (ip) {
-		xfs_iunlock(ip, XFS_ILOCK_EXCL);
-		xfs_finish_inode_setup(ip);
-		xfs_irele(ip);
+	if (du.ip) {
+		xfs_iunlock(du.ip, XFS_ILOCK_EXCL);
+		xfs_finish_inode_setup(du.ip);
+		xfs_irele(du.ip);
 	}
  out_parent:
-	xfs_parent_finish(mp, ppargs);
+	xfs_parent_finish(mp, du.ppargs);
  out_release_dquots:
 	xfs_qm_dqrele(udqp);
 	xfs_qm_dqrele(gdqp);

fs/xfs/xfs_symlink.c

@@ -95,8 +95,11 @@ xfs_symlink(
 		.pip		= dp,
 		.mode		= S_IFLNK | (mode & ~S_IFMT),
 	};
+	struct xfs_dir_update	du = {
+		.dp		= dp,
+		.name		= link_name,
+	};
 	struct xfs_trans	*tp = NULL;
-	struct xfs_inode	*ip = NULL;
 	int			error = 0;
 	int			pathlen;
 	bool                    unlock_dp_on_error = false;
@@ -106,7 +109,6 @@ xfs_symlink(
 	struct xfs_dquot	*pdqp;
 	uint			resblks;
 	xfs_ino_t		ino;
-	struct xfs_parent_args	*ppargs;
 
 	*ipp = NULL;
 
@@ -140,7 +142,7 @@ xfs_symlink(
 		fs_blocks = xfs_symlink_blocks(mp, pathlen);
 	resblks = xfs_symlink_space_res(mp, link_name->len, fs_blocks);
 
-	error = xfs_parent_start(mp, &ppargs);
+	error = xfs_parent_start(mp, &du.ppargs);
 	if (error)
 		goto out_release_dquots;
 
@@ -165,7 +167,7 @@ xfs_symlink(
 	 */
 	error = xfs_dialloc(&tp, dp->i_ino, S_IFLNK, &ino);
 	if (!error)
-		error = xfs_icreate(tp, ino, &args, &ip);
+		error = xfs_icreate(tp, ino, &args, &du.ip);
 	if (error)
 		goto out_trans_cancel;
 
@@ -181,33 +183,24 @@ xfs_symlink(
 	/*
 	 * Also attach the dquot(s) to it, if applicable.
 	 */
-	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
+	xfs_qm_vop_create_dqattach(tp, du.ip, udqp, gdqp, pdqp);
 
 	resblks -= XFS_IALLOC_SPACE_RES(mp);
-	error = xfs_symlink_write_target(tp, ip, ip->i_ino, target_path,
+	error = xfs_symlink_write_target(tp, du.ip, du.ip->i_ino, target_path,
 			pathlen, fs_blocks, resblks);
 	if (error)
 		goto out_trans_cancel;
 	resblks -= fs_blocks;
-	i_size_write(VFS_I(ip), ip->i_disk_size);
+	i_size_write(VFS_I(du.ip), du.ip->i_disk_size);
 
 	/*
 	 * Create the directory entry for the symlink.
 	 */
-	error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks);
+	error = xfs_dir_create_child(tp, resblks, &du);
 	if (error)
 		goto out_trans_cancel;
-	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
-	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
-
-	/* Add parent pointer for the new symlink. */
-	if (ppargs) {
-		error = xfs_parent_addname(tp, ppargs, dp, link_name, ip);
-		if (error)
-			goto out_trans_cancel;
-	}
 
-	xfs_dir_update_hook(dp, ip, 1, link_name);
+	xfs_dir_update_hook(dp, du.ip, 1, link_name);
 
 	/*
 	 * If this is a synchronous mount, make sure that the
@@ -225,10 +218,10 @@ xfs_symlink(
 	xfs_qm_dqrele(gdqp);
 	xfs_qm_dqrele(pdqp);
 
-	*ipp = ip;
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	*ipp = du.ip;
+	xfs_iunlock(du.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:
@@ -239,13 +232,13 @@ xfs_symlink(
 	 * setup of the inode and release the inode.  This prevents recursive
 	 * transactions and deadlocks from xfs_inactive.
 	 */
-	if (ip) {
-		xfs_iunlock(ip, XFS_ILOCK_EXCL);
-		xfs_finish_inode_setup(ip);
-		xfs_irele(ip);
+	if (du.ip) {
+		xfs_iunlock(du.ip, XFS_ILOCK_EXCL);
+		xfs_finish_inode_setup(du.ip);
+		xfs_irele(du.ip);
 	}
 out_parent:
-	xfs_parent_finish(mp, ppargs);
+	xfs_parent_finish(mp, du.ppargs);
 out_release_dquots:
 	xfs_qm_dqrele(udqp);
 	xfs_qm_dqrele(gdqp);