libfrog: add directory tree structure scrubber to scrub library

Make it so that scrub clients can detect corruptions within the
directory tree structure itself.  Update the documentation for the scrub
ioctl to mention this new functionality.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/libfrog/scrub.c b/libfrog/scrub.c
index baaa4b4d9402c7996b83e9c74dd54e266f7dbb9c..a2146e228f5b6dbdf7e9aa4d4a2d22dc79078f16 100644 (file)
--- a/libfrog/scrub.c
+++ b/libfrog/scrub.c
@@ -149,6 +149,11 @@ const struct xfrog_scrub_descr xfrog_scrubbers[XFS_SCRUB_TYPE_NR] = {
                .descr  = "retained health records",
                .group  = XFROG_SCRUB_GROUP_NONE,
        },
+       [XFS_SCRUB_TYPE_DIRTREE] = {
+               .name   = "dirtree",
+               .descr  = "directory tree structure",
+               .group  = XFROG_SCRUB_GROUP_INODE,
+       },
 };
 #undef DEP
 

diff --git a/man/man2/ioctl_xfs_scrub_metadata.2 b/man/man2/ioctl_xfs_scrub_metadata.2
index 75ae52bb5847a394bc6dd6e50abb6d091fe1dbf8..44aa139b297a3b02565b61842d575d028a5937e5 100644 (file)
--- a/man/man2/ioctl_xfs_scrub_metadata.2
+++ b/man/man2/ioctl_xfs_scrub_metadata.2
@@ -148,6 +148,20 @@ that points back to the subdirectory.
 The inode to examine can be specified in the same manner as
 .BR XFS_SCRUB_TYPE_INODE "."
 
+.TP
+.B XFS_SCRUB_TYPE_DIRTREE
+This scrubber looks for problems in the directory tree structure such as loops
+and directories accessible through more than one path.
+Problems are detected by walking parent pointers upwards towards the root.
+Loops are detected by comparing the parent directory at each step against the
+directories already examined.
+Directories with multiple paths are detected by counting the parent pointers
+attached to a directory.
+Non-directories do not have links pointing away from the directory tree root
+and can be skipped.
+The directory to examine can be specified in the same manner as
+.BR XFS_SCRUB_TYPE_INODE "."
+
 .TP
 .B XFS_SCRUB_TYPE_SYMLINK
 Examine the target of a symbolic link for obvious pathname problems.