[PATCH 21/26] xfs: create libxfs helper to remove an existing inode/name from a directory

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Darrick J. Wong <djwong@xxxxxxxxxx>

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: Darrick J. Wong <djwong@xxxxxxxxxx>
---
 libxfs/xfs_dir2.c |   73 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 libxfs/xfs_dir2.h |    3 ++
 2 files changed, 76 insertions(+)


diff --git a/libxfs/xfs_dir2.c b/libxfs/xfs_dir2.c
index 8755ef615f8..a0853d766f2 100644
--- a/libxfs/xfs_dir2.c
+++ b/libxfs/xfs_dir2.c
@@ -876,3 +876,76 @@ xfs_dir_link_existing_child(
 	xfs_bumplink(tp, ip);
 	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,
+	uint				resblks,
+	struct xfs_inode		*dp,
+	struct xfs_name			*name,
+	struct xfs_inode		*ip)
+{
+	int				error;
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+	ASSERT(xfs_isilocked(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;
+	}
+
+	return 0;
+}
diff --git a/libxfs/xfs_dir2.h b/libxfs/xfs_dir2.h
index 4afade8b087..e35deb273d8 100644
--- a/libxfs/xfs_dir2.h
+++ b/libxfs/xfs_dir2.h
@@ -259,5 +259,8 @@ int xfs_dir_create_new_child(struct xfs_trans *tp, uint resblks,
 int xfs_dir_link_existing_child(struct xfs_trans *tp, uint resblks,
 		struct xfs_inode *dp, struct xfs_name *name,
 		struct xfs_inode *ip);
+int xfs_dir_remove_child(struct xfs_trans *tp, uint resblks,
+		struct xfs_inode *dp, struct xfs_name *name,
+		struct xfs_inode *ip);
 
 #endif	/* __XFS_DIR2_H__ */




[Index of Archives]     [XFS Filesystem Development (older mail)]     [Linux Filesystem Development]     [Linux Audio Users]     [Yosemite Trails]     [Linux Kernel]     [Linux RAID]     [Linux SCSI]


  Powered by Linux