From: Darrick J. Wong <djwong@xxxxxxxxxx>
Source kernel commit: 90636e4531a8bfb5ef37d38a76eb97e5f5793deb
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>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
libxfs/xfs_dir2.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++
libxfs/xfs_dir2.h | 2 +
2 files changed, 83 insertions(+)
diff --git a/libxfs/xfs_dir2.c b/libxfs/xfs_dir2.c
index 802b9a1b3..e46f7f489 100644
--- a/libxfs/xfs_dir2.c
+++ b/libxfs/xfs_dir2.c
@@ -873,3 +873,84 @@ 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;
+}
diff --git a/libxfs/xfs_dir2.h b/libxfs/xfs_dir2.h
index 4f9711509..c89916d1c 100644
--- a/libxfs/xfs_dir2.h
+++ b/libxfs/xfs_dir2.h
@@ -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__ */
